# Petition for Writ of Certiorari — Eimco Corp. v. Peterson Filters & Engineering Co.

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## Record

- **Collection:** Supreme Court brief
- **Document type:** Petition for Writ of Certiorari
- **Published:** January 1, 1969
- **Citation:** 395 U.S. 963

## Text

; coi : e3 r
stantial public interest which has not, been but should be
* settled by this Court. |

Constitutional Reaves and Statutes Involved

This case involves the patent clause of the Consti-
tution of the United States, Article I, Section 8, Clause
8 (A1), and 35 U.S.C. §§102(a) and -(b) and 103 (A1).

Statement of the Case

This is an action for infringement of United States
Patent No. 3,077,990 issued February 19, 1963, to J. G.
P@terson for ‘‘Filter Medium Guide.’’ The District
Court’s jurisdiction was properly based on 28 U.S.C.
-§1338(a). oF aes

Petitioner was defendant and respondents were plain-
tiffs in the District Court.

i

The District Court adjudged the two claims of the
patent to be valid and infringed by petitioner, and the
Court of Appeals affirmed. |

2. See Borg-Warner Corporation v. Paragon Gear Works, Inc., .
355 F.2d 400 (1st Cir. 1965) ; Powder Power Tool Corp. v. Powder
Actuated Tool Co., 230 F.2d 409 (7th Cir. 1956) ; Keating v. Stear-
nes Imperial Co., 347 F.2d 444 (7th Cir. 1965) ; Parke, Davis & Co.
v. American Cyanamid Co., 207 F.2d 571 (6th Cir. 1953).

i) |

Subject Matter Involved

The patent in suit relates to an apparatus to stretch,
tension and maintain the alignment of a filter medium,
sometimes called web or belt, used on rotary drum vacuum
belt filters having a discharge section spaced from the
drum. Filters of this type are sometimes referred to as
belt discharge filters. For convenience, Exhibit C (R. 780),
an illustrative isometric drawing of one of petitioner’s belt
discharge filters is included in the Appendix hereto (A53).

Belt Discharge Filters

Belt discharge filters. utilize a cylindrical filter drum
having closed ends but having perforations in the cylin- ;
drical or ‘‘deck’’ surface. The drum may vary in size.
In operation, the cylindrical deck surface is covered for the
greater part of its periphery by an endless filter belt. The
perforated deck is connected by ‘pipes to an automatic
rotary valve. The drum is positioned with respect to a
tank containing a slurry of liquids and solids so that, as
the drum rotates, a portion thereof, covered by the filter
belt, is immersed in the slurry. By means of the rotary
valve, a vacuum i8 pulled on the underside of the filter
drum so immersed and for a short period thereafter. The
liquid phase of the slurry is thus drawn through the filter
belt to the interior of the drum, and thence directed to
settling tanks. The solid material (sometimes called cake)
is deposited on the surface of the belt (R. 1493- ates

As the drum rotates, the filter elt, on which the cake
has been deposited, leaves the slurry and, as the drum
continues its rotation, the filter belt is withdrawn from the

Sons.
6 ‘“
drum and passes over a discharge roller where an abrupt
change in the direction of travel of the filter belt causes

the cake to fall off the belt (R. 1494).

,

The filter belt then passes (a) directly to the return roll
*(two-roll system), or (b) over one or more wash or idler
rollers, and thence to. the return roll (three and five roll

“systems). From the return roll the belt passes directly -

back to the drum, where it again engages the perforated
deck of the drum for a repetition of the filtering cycle (R.
1494).

Filter apparatus as described above was, admittedly,
not the invention of Peterson but constitutes the environ-
ment in which the Peterson apparatus was intended to be
used.

Filter Beit Alignment Problems

In normal operation of a belt discharge filter, the belt
sometimes tends to track, laterally to one side or the other
of the drum. In such cases, if the mistracking is not cor-
rected, the, belt will mistrack onto the filter drum ‘and some
of the perforated area of the drum that should be covered
by the belt when the drum is immersed in the slurry will
be exposed to the slurry. When this occurs, the filtraté
will be contaminated and eventually the filter will’ become
inoperative (R. 930).

Mistracking occurs for many reasons, such .as inac-
curacies in the manufacture of the belt (R. 1501) or the

filter drum (R. 930), misalignment of one or more of the ©
rolls of the filter apparatus, variations in the load of filter |

7

cake carried by the belt, or incomplete discharge of filter
cake from the belt (R. 977).

Over the years, a varfety of devices have been and still
are used by the filter industry to correct for misalignment
of the filter belt (R. 1450- 1452).

a

The Peterson Patent

The Peterson patent in suit (Ex. 1, R. 656, A48-52) dis-
closes and claims one type of filter belt aligning. device.
The claimed device is, essentially, a combination of ap-
paratus comprising the following components: (a) the re-
turn roller of the filter apparatus (over which the filter
belt passes Just prior to returning to the drum and an
essential component of any belt discharge filter); (b) a
filter belt having beaded edges; (c) two pairs of guide
wheels or roilers, one pair to coact with each of the beaded
edges of the filter belt; (d) mounting means for mounting
the pairs of guide’ wheels or rollers adjacent each end of
the return roller; and (e) adjustable spring or other re-
silient means (as distinguished from an adjustable. manual-
ly operated tensioning rod or a weight system, also dis-
closed is the patent) associated with each of the pairs of

guide wheels or rollers to impart a tensioning force to each

of the pairs of guide. wheels to urge such guide wheels lat-
erally outwardly of the path of travel of the belt so as
to maintain the belt stretched and in alignment.

The Issue Concerning Obviousness

The patent specification and drivinws (A48- 52) disclose,
and the original application claimed (Ex. 2, R. 669-672)

three alternative ‘‘embodiments’’ of the Peterson ‘‘inven-

FOTN T TI sete Deeg

Se Ce a ne nee Rn eed ee ee
c we

iE

8

tion”, each embodiment differing from the others only by

_ the employment of a different méchanical expedient for in-

ducing a tensioning force or pressure to urge each of the
two pairs of guide wheels against the beaded edges of
the belt and laterally outwardly of the path of travel of the
belt. These expedients included (a) a system of weights
(A49, Figure 5, application claim 9, R. 671); (b) a system
employing a manually operated threaded tensioning rod,
adjusted by a hand wheel connected to the rod (A48, Figure
2, application claim 10, Ex. 2, R. 671); and (c) a system
of springs (A48-49, Figures 3; 4 and 6, application claims
3, 8 and 12, R. 669, 671, 672).°

The manually operable tensioning rod system in sub-
stantially the same form as shown in Figure 2 of the Peter-

son patent is disclosed in prior art Swiss patent (Ex. U,

R. 794) where it serves to apply a tensioning force to op- -
positely disposed pairs of guide wheels coacting with beaded

edges of a web or belt to guide and align the web or belt.

The prior art Warner patent (Ex. Z, R. 794) shows a
system of weights and pulleys substantially similar to those
shown in the Peterson patent to apply a -tensioning force
to roller members in a web stretching device.

"The record does not show what motivated Peterson to
select springs or other resilient means—to the exclusion of
the other alternative expedients. disclosed, in his patent

- and originally claimed ‘as species of the same genus—to

provide the tensioning force for his guide wheels.in the
claims that issued in his patent since neither the Swiss

3. Original claims 1, 2, 4 through 7 and 11 were generic to all
three of the illustrated expedients for imparting a tensioning force
to the guide wheels. -

9

patent nor the Warner patent, referred to, were. brought
to the attention of the Patent Office (but were before the
courts below).

However, because the prior art did nak disclose the. use
of springs, or other resilient means (District Court, A26-
27; Court of Appeals, A6), to apply a tensioning force to
guide wheels ceacting with beaded edges of’a belt to ten-
sion and center the belt, both courts below held (District
Court, A27-28; Court of Appeals, A8-11) that this single
point of difference between the prior art and the combina- -
tion claimed by Peterson. was sufficient to justify the hold-
ing that the claimed combination satisfied the nonobvious
requirements of §103.

In reaching this holding, the courts below have either
confused the ‘‘novelty’’ requirements of §§102(a) and (b)
with the ‘‘nonobvious”’ | requirements of §103, or have
ignored the mandate of this Court in Graham v. John Deere
Co., supra, for determining nonobviousness of the claimed
subject matter. In either case, the decisions below are in
clear conflict with the decision of this Court i in Graham v.
John Deere Co., supra.

- The Issue Concerning the Scope of the Patent Claims

Claims 1 through 10 of the claims submitted with the -
Peterson application as filed specified that the ‘guide
rollers’’ of the claimed combination be mounted ‘‘adjacent
the drum’? of the filter apparatus (R. 669-671).

These ten original claims, along with original claims

_ 11 and 12 which positioned the guide wheels as “juxta-_

~

10
posed the return roller’? (R. 672), were rejected in the
second Patent Office Action (Ex. 2, R. 683, 684) on the
grounds (1) that they were ‘‘indefinite’’ and ‘‘somewhat
misdescriptive’’ and (2) were ‘‘fairly met’’ by. cited prior.
art. : |

“fhe applicant forthwith canceled original claims 1
through 12 and submitted in their stead application claims
18 and 19 (Patent claims 1 and 2 as issued). These
substituted claims are identical in substance—apart from
form—to canceled original claims’ 3 and 8 except that
patent claims 1 and. 2 specify that the guide wheels be
mounted ‘‘adjacent each end of. the return roller’’ of the
filter apparatus, whereas original claims 3 and 8 positioned
the guide wheels ‘‘adjacent the drum.’ This modification ®
of. the claims was deliberately made. The remarks accom-
panying the amendment contained the statement:

‘*Claim 18 is written along the lines of Claim 11
pointing out more particularly that the filter medium
rollers are placed adjacent a return roller and have
placed between them .the filter medium with the edge
bead on the outside.’’? (Emphasis added) (R. 685-688)

At the trial, respondents’ expert testified (R. 1263-1264,
1409) that ‘‘adjacent each end of the return roller’’ as’
used in the Peterson patent claims meant positioned along
the edges of the belt at a point where no other: element
of the filter apparatus intervened between the guide wheels
and the return roller.» While neither of the courts below

4. Application claim 3 is dependent upon and must be read: with
application claim 1. Application claim 8 is dependent upon and must

_be-read with application claim 7. .
Fal

5. In the courts below petitioner contended that the phrase
“adjacent each end of the return roller” meant, in addition, Jaterally
adjacent the ends of such roller as shown in the Peterson patent _
Figures 2, 3, 4, 5 and 6. e ;

11

stated specifically what was meant by the limitation ‘‘ad-

jacent each end of the return roller’’ in the patent claims, ;

both adopted the testimony of respondents’ expert and
held that petitioner’s device positioned at a point about
midway between the return roller and the: next preced-
ing wash roller,® position A or the sketch below, was mount-
ed “adjacent cach end of the return roller’? and infringed
the Peterson claims literally ; but that petitioner’s devices
‘mounted at positions B and C did not infringe in terms ei-
ther claim since petitioner’s devices, at these positions, were
not mounted ‘‘adjacent each end of the return roller’’ be-
cause other rollers in the filter system intervened between

the guide wheels and the return roller (A12, 35). Indeed, .

when mounted at position C, petitioner’s apparatus was
‘‘adjacent the drum’’ (according to the definition ascribed
to the word ‘‘adjacent’’ by respondents’ expert). and hence
directly within the scope of canceled original claims 3
and 8.

,

6. For convenience, petitioner has reproduced below a schematic
diagram that depicts a basic three-roll belt discharge filter (based on

Ex. B,-R: 779) and shows (1) the relationship of the drum, discharge.
roller, wash roller and return roller as normally used in such filters, :

and (2) three different positions designated A, B and C at which pe-
titioner’s accused web guiding mechanisms have been installed. Peti-
tioner’s devives, installed at position C, have been mounted at sev-
eral locations along the path of travel of the web designated generally
by the bracket associated with the letter C on the sketch.

ROLL

ONE TINNED AEE,

le

12

Both courts below nevertheless held that because pe-

» titioner’s devices, mounted at positions A, B or C, served

to align the belt, all three were equivalents an::, under the
doctrine of equivalents, were encompassed by and _ in-
fringed the Peterson patent claims (A12-15, 35-36).

- This, the decisions of the courts below have accorded
the Peterson claims a construction that enables Peterson
to recapture the precise subject matter of ‘eaneeled orig-
inal claims 3 and 8.

-Petitigner submits that in so holding, the decisions of
the courts below either (1) conflict directly with the decision
of this Court in Exhibit Supply Co., supra, or (2) raise an

_ important question of patent law as to the extent to which

the file wrapper estoppel rule applies to claims submitted
in lieu of canceled claims where the canceled elaims were
rejected both on prior art and for informalities in claim
language, a question which has not been but should be
settled by this Court.

In any event the decisions below impose limitations on
the file wrapper estoppel rule that conflict directly with
the applicable decisions of the Courts of Appeals for the
First, Sixth and Seventh Circuits.

13

Reasons for Granting the Writ .

1. The Poenewen of the Court of Appeals upholds the
' monopoly of a patent which fails completely to meet
the “nonobvious” requirement of 35 U.S.C. §103.

This Court,.in Graham v. John Deere Co., 383 U.S. 1
( 1966), stated that 30 U.S.C. §103 (A1), was not intended
by Congress to change the general level of patentable in- |
vention for subject matter sought to be patented and not
identically disclosed in the prior art, but was intended to
impose on the courts, in such instances, the directive to
inquire into the obviousness of the subject matter sought
to be patented as a prerequisite to nn. (383 U.S.
at p. 17). .

The Court then said (383 U. S. at p. 17): :

‘‘While the ultimate question of patent validity is
one of law, A. & P. Tea Co. v. Supermarket Corp., su-
pra; at 155, the §103 condition, which is but-one of three |
conditions, each of which must be satisfied, lends itself”
to several basic factual inquiries. Under §103, the
scope and content of the prior art are to be determined ;
differences between the prior art and the claims at |
issue are to be ascertained; and the level of ordinary _
skill in the pertinent art resolved. Against this back-
ground, the obviousness or nonobviousness of the sub-
“ject matter is determined.- Such secondary considera-
tions as commercial success, long felt but unsolved
needs, failure of others, ete., might be utilized to give
light to the circumstances’ surrounding the origin of the.
‘subject matter sought to be patented. As indicia of
obviousness or nonobviousness, these inquiries may
have relevancy. wl

14

and coutinued with the admonition that (383 U.S. at p. 18) :-

‘strict observance of the requirements laid down here
will ‘result in that uniformity and definiteness which
Congress called for in the 1952 Act.’’

In. this case, it is immaterial whether the subject matter ©

of the claims of the Peterson patent in suit is tested against
the nonobviousness requirements of §103 as set forth in
Graham or against the judicial precedent for §103 as ex-
pressed in A. & P. Tea Co. v. Supermarket Corp., 340 U.S.
147 (1950) ; Altoona Theatres v. American Tri-Ergon Corp.,
294 U.S. 477, 486 (1935) ; Sinclair Co. v. Interchemical Corp.,
325 U.S. 327 (1945), and Lincoln Co. v. Stewart-Warner
Corp., 303 U.S. 545 (1938), among others.

In either case, the combination of the Peterson claims
fails completely to satisfy the tests steadfastly adhered
to by this Court since’ Hotchkiss v. Greenwood, 11 How.
248 (1850) as justification of a private grant on the public
domain. |

The web aligning und tensioning apparatus of the Peter-
son claims, at best, required a very low order of skill for
a mechanic working in the filter field. See, for example,
the unequivocal statement of patentee Peterson (R. 964,
965) that ‘‘* * * at the time of this concept I wasn’t in-
telligent enough to know that the cloth had to slide at that
time on the return roller * * *’’—as the belt passed over
the return roller when the guide wheels were positioned

at the end of the return roller as in Figure 2 (A48) of
the patent. | |

The prior art Clark patent (Ex. K, R. 786) disclosed

a belt discharge filter, including a drum, discharge roller, —

15

wash roller and return roller which employed a filter belt
with beaded edges. The use of guide wheels coacting with
the beaded edges of a belt and one of the three expedients
disclosed by Peterson for imparting a tensioning ‘force to
such guide wheels (the tensioning rod system) to cause them
to coact with the beaded edges of the belt to tension and
center the belt are shown in the Swiss patent (Ex. U, R.
794). The Warner patent disclosed another of Peterson’s
expedients for imparting tension to the guide wheels
(weights and pulleys) in a slightly different environment
(Ex. Z, R. 794).

Thus, as each of the courts below held (A6, 26-27), the
only feature of the apparatus claimed in the Peterson
patent claims not shown in the prior art discussed above is
the use of springs or other resilient means to impart the
tensioning force to the guide wheels—and that feature is
shown in the patent as an alternative expedient to the prior
art tensioning rod and weight systems which Peterson
originally claimed as species of his inventive concept.

In the circumstances, the comments of the Court in
Technograph Printed Circwits Ltd. v. Bendix Aviation
Corp., 218 F.Supp. 1 (Md. 1963), affirmed, per curiam,
327 F.2d 497 (4th Cir. 1964), seem particularly apt. There
it-was said of the Kisler patent in suit in that ease (218
F.Supp. at p. 24):

‘“The case * * * is that of one who thought his inven-
tion was a pioneering one, and who therefore initially
claimed more than he himself later realized could be
claimed; and who therefore disclosed in his specifica-
tions a number of equivalents. Many if not all of these

a |

ws Neher arcnpe

16
were clearly within the prior art. If in fact they, or
any one of them, is within the prior art, and they are

equivalents, there is no invention in the substitution of
one for any other.’’

In the present case there can be no valid contention that
the substitution of springs for weights or springs for manu-
ally operated tensioning rods involved invention.

All three of these mechanical expedients were shown as
permissible alternatives and within the concept of the in-
vention for which Peterson originally filed application for
patent (Ex. 2, R. 657).

No function other than that inherent in the spring is
served by the spring means claimed. Weights and springs
have been judicially recognized as mechanical equivalents

in a machine since at least as early as 1879 (Imhaeuser v. .

Buerk, 101 U.S. 647, 656 (1879)). Indeed, as was caid in
Kenney Mfg. Co. v. J. L. Mott Iron Works, 137 F. 431, 433
(S.D.N.Y. 1905), ‘‘the interchangeable use of weights and
springs is the stock: illustration for equivalents.’? The
use of tensioning rods is but another equally available and
well known mechanjcal, expedient and was recognized as
such by Peterson in his patent (A48-52). Each of these
expedients is endowed with its own inherent advantages
and disadvantages; and all were equally well known in the
mechanical arts long before Peterson entered the field.
The selection of one in the place of another was wholly
dependent on the extent to which the inherent function-
ing of the expedient selected met the requirements of the
mechanic.

17

There is no suggestion in the record of this case of any
problems incident to the adoption or use of springs in the

Peterson combination. Indeed, the Peterson patent clearly

indicates the absence of such problems.

Nor is there any indication that Peterson’s use of
springs in his claimed combination served to make available
an apparatus that satisfied any long-felt but unsolved prob-
lem. ‘On the’ contrary, the record shows-by wholly uncon-
troverted testimony that (notwithstanding the complete
lack 0° wy use by either respondent of any device such as

disclosed by the Peterson patent, A28-29) when a desire -

was voiced for spring-biased guide wheel mechanisms to

align filter belts, such device was immediately forthcom-.

ing, produced by petitioner’s engineers prior to the issu-
ance of the Peterson patent and without benefit of the dis-
closures of that patent (R. 1454-1462)..

In tbe circumstances, Peterson’s selection of spring
means for his claimed combination in lieu of the manually
operated tensioning rod or weight disclosed in the. prior
art‘ and shown as alternatives in his patent certainly was
no less obvious than was: ae

(1) Graham’s inverting .and fnodifying the coupling
of a chisel plow shank with respect to the hinge’ plate
to effect free flexing of the shank, which this Court held
did not meet the nonobvious requirements of §103 in
Graham v. John Deere Co., supra. |

(2) Gessler’s selection of known ingredients (each
endowed with its own inherent characteristics) to eom-
pound a quick drying ink which this Court held to be

ag

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Pou

18

unpatentable in Sinclair Co. v. Interchemical Corp., 325
U.S. 327 (1945).

(3) Vogt’s selection of a flywheel to assure accuracy
and precision of film movement in apparatus for reecord-
ing and reproducing talking pictures, which the Court
held to fall short of patentable invention in Altoona The-
atres v. American Tri-Ergon Corp., 294 US. 477 (1935).

(4) Turnham’ ’s eashier’s counter and movable frame,
held to be unpatentable in 4. & P. Tea Co. v. sa dbl
Corp., 340 U.S. 147 (1950) ; or

(5) Butler’s utilization of an improved coupler in an
old combination of elements comprising a lubricating ap-
paratus, which this Court held to be an aggregation. of
known elements, each serving its intended function and,
hence, failing to reach the dignity of a patentable inven-|
tion, in Lincoln Co. v. Stewart-Warner Corp., 303 U.S. 545.
(19388). .

In each of the last two cited cases (A. & P. Tea Co.,
supra, and Lincoln Co., supra), as here, the District ‘Court
had found the patent in suit valid and its judgment was
affirmed by the Court of Appeals. This Court, in each
‘instanee, considered carefully the ‘‘combinations’’ of the
patents there in suit and concluded that they failed to meet
this Court’s requirements for patentable invention. The
Court said, in A. & P. Tea Co. (340 U.S. at pp. 152, 153-
154): | e

‘Courts should scrutinize’ combination patent
claims with a care proportioned to the difficulty and

- 19

improbability of finding invention in an assembly of —

old elements. The function of a patent is to add to
the sum of useful knowledge. Patents cannot be sus-
tained when, on the contrary, their effect is to sub-
‘tract from former resources freely available to skilled
artisans. A patent for a combination which only
unites old elements with no change in theiy respective
functions, such as is presented here, obviously with-
draws what already is known into the field of its
monopoly and diminishes the resources available to
skillful men. This patentee has added nothing to
the total stock of knowledge, but has merely brought
together segments of prior art and claims them in
congregation as a monopoly. ;

* * *

‘“The questions of general importancé considered here
are not contingent upon resolving conflicting testi-
mony, for the facts.are little in‘dispute. We set
aside no finding of fact as to invention, for none has
been made except as to the extension of the counter,
‘which cannot stand as a matter of law. The defect
that we find in this judgment is that a standard of
invention appears to have been used that is less ex-
acting than that required where a combination is made
up entirely of old components.’’

In the present ease, neither Peterson nor either of
the courts below has suggested that Peterson’ invented
the spring or any particular apparatus for adapting a
spring to the other elements of his claimed combina-
tion, all of which were per se old. In the Peterson
claimed combination, the spring is used for the same pur-
pose for which all springs are ,used in machines, to impart
a tensioning force or pressure to a component of the ap-
paratus, and neither Peterson nor either of the courts be-

PERO SH LPL I |
ee on .

20

_low has suggested any change in the respective functions
of any of the components of the claimed combination. The
Peterson patent adds nothing to the sum of. useful knowl-
edge. By holding such a patent valid, the decisions of the
courts below serve only to diminish the resources available
to skillful men. }

_ ‘The decisions below are in- conflict with the controlling
decisions of this Court. The petition should be granted
to allow this Court to make it unequivocally clear that the
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Constitutional Provision and Statutes Involved

Constitution

ARTICLE 1 |

Section 8. The Congress shall have the Power * * * |

To promote the Progress of Science and useful Arts,
by securing for limited Times to Authors and Inventors
the exclusive Right to their respective Writings and Dis-

coveries; * * *,

Statutes
35 UNITED STaTEs CopE

.§102. Conditions for patentability; novelty and loss of
right to patent

_ A person shall be entitled to a patent unless—

(a) the invention was known or used by others in this
country, or patented or described in a printed’ publication
in this or a foreign country, before the invention thereof
by the applicant for patent, or

(b) the invention‘was patented or described in a printed
publication in this or a foreign country or in public use or
on sale in this country, more than one year prior to the
date of the application for patént in the United States, * * *.

_ §103. Conditions for patentability; non-obvious - subject
| matter J

A patent may not be obtained though the invention is not
identically disclosed or described as set forth in section 102
of this title, if the differences between the subject matter
sought to be patented and the prior art are such-that the
subject matter as a whole would have been obvious at the
time the invention was made to a person having ordinary
skill in the art to which said subject matter pertains. Pat-
_ entability shall not be negatived by the manner in which

7 ® ”

A2

Opinion of United States Court of Appeals

UNITED STATES COURT,OF APPEALS

TENTH CIRCUIT

- DecemMBER TERM—1968

No. 9806

Tue Eimco Corporation,
: Appellant,

- - Vv.

Prererson FILTERS AND ENGINEERING Company and KoMLINE-
SANDERSON E\NGINEERING CORPORATION,

Appellees.

APPEAL FROM THE Unitrep States District Court .
ror tHe District or Utau, CentTRAL Division
(No. 33-66 Civil) , gi

rt

Before:

Pickett, Lewis and Hickey, Cireuit Judges

A3

,

Opinion of the United States Court of Appeals

Pickett, Circuit Judge |

This is a patent infringement suit in which the appel-
lees, Peterson Filters and Engineering Company and
Komline-Sanderson Engineering Corporation, allege in-
fringement of Patent No. 3077990 and seek damages,
together with injunctive relief prohibiting further infringe-
ment.’ The objects of the patent are to overeome tracking
and wrinkling problems encountered in the operation of
a rotating endless filter belt. The trial court rejected a
defense of ‘invalidity and held the patent valid and in-
fringed. | ;

The patent discloses a device for the alignment of

filter belts on an apparatus which is used in the sanitation
and industrial fields to separate liquid from solids. In
operation the filter belt is a part 5f a rotary drum filter
machine, the drum being positioned in a tank containing
the fluid to be separated and referred to in this litiga-
tion.as ‘‘slurry’’. The drum is cylindrical in shape, with
closed ends and a perforated surface. Spaced from the
drum surface is a cleaning section consisting. of a dis-

charge roller and other rollers the number of which varies -

depending upon the type of machine used. The endless
filter belt is looped over the drum and the discharge sec-
tion assembly. Necessarily the belt is substantially longer
than the circumference of the drum. For efficient opera-
tion all of the perforated portion of the drum, which is

_ immersed in the slurry, aust be completely covered by

1. The patent was issued to John G. Peterson on February 19,
1963, and later assigned to Peterson Filters and Engineering Com-
pany. Komline-Sanderson Engineering Corporation .is an exclusive
licensee under the patent, restricted to the field of sanitation and has
a réstricted right to sue for infringement.

4

FOAM pele YS ORT Sieg PRN

id

A4
| Opinion of the United States Court of Appeals

the filter belt to prevent the entry of the raw slurry into
the drum and thence into the pipes and valves, thereby
—eausing the filter mechanism to become inoperative. By
means of a rotary valve, a vacuum is created on the under
side of the filter belt and the liquid phase of the slurry
is drawn through the filter to the interior of the drum
and the solids remain on the surface. As the drum rotates,
the belt leaves the surface of the drum and passes over
the rollers of the discharge system. At the first roller
there is an abrupt change in the course of the belt which
causes the solids to fall off. Thereafter the belt. continues
over additional rollers for cleaning and positioning for
veturn to the drum surface and commencement of another
filter cycle. Due to various causes, the filter belts when
. passing over the rollers have had a tendency to ereep
either to the right or, left, preventing return. of the belt
to the drum head in a manner which would cover all of
the perforated surface thereof. Such misalignment of
the belt also causes a wrinkling which tends to prevent
a satisfactory operation. The vacuum drum filter belt
process was well known in the art at the time of the issu-
ance of the-Peterson patent, but the new element claimed
in this combination was a filter belt guide which contin-
uously and automatically realigns the belt before it re-
turns to the drum surface.

2. The patent states that it is “an important object of the inven-
tion to provide a novel filter medium and mechanism for maintaining
an endless filter medium centered on a rotary drum and through a
discharge section spaced from the drum surface. The invention pro- _
vides centering of the medium, eliminates wrinkling of the material
of the filtering medium either on the drum or in the discharge section,
and provides positive tracking for the.medium onto the drum without
training rods. ‘The mechanism of the invention laterally stretches the
filter medium, retarding blinding of its openings and provides for
more complete cleaning of the filter medium prior to its return to the
filter drum for additional filtering action,”

AS

Opinion of the United States Court of Appeals

it

‘The realignment device disclosed in the Peterson
patent consists of two pairs of guide rollers or wheels
with springs attached, mounted one adjacent each end. of
the last roller before the belt returns to the drum. These
wheels. bear against the beaded edges on the outer sides
of the belt and force it lateraliy outward, away from the
center. The tension creating the foree of the guide rollers
when engaging the beading is provided by adjustable
attached springs. The assembled tensioning and guiding
device includes means for adjusting the amount of lateral
tension to be applied.* If the realignment device is
mounted at the ends of a roller, sufficient foree must be
applied against the beading to cause the belt to slide

3. The patent claims are as follows:

1. In a filter medium tracking and tensioning device for a
rotary. drum filter having -a separate cake discharge section, an
endless filter medium looped over the filter drum and extending
through the cake discharge section, which filter medium includes |
a bead on each edge of the filter medium extending completely
therearound, and.a filter medium return roller mounted adjacent _
the filter drum, the improvement which comprises means for
tracking the filter medium back to said drum inclusive of a pair
of rollers mounted adjacent each end of the return .roller, each
pair of rollers being mounted in substantial contacting relation
and mounted with the filter medium therebetween and in posi-
tion to bear against the bead at the edge thereof, each said pairs
of rollers being arranged to move laterally i in respect to the path
of travel of the filter medium, resilient means attached to said
‘rollers in position so that the rollers bear against the bead at
each side of the filter medium to stretch the filter medium there-
between and to center it in relation to the return roller and the
filter drum, and means for supporting each pair of said rollers
in position on said filter medium and biased against the adjacent
bead at the edge thereof.

2. A device according to claim 1 in which each said pair of
bead contacting rollers is spring biased laterally away from, the
filter medium so as to provide essentially uniform tensioning on
the filter medium. (Claims 1 and 2 from patent.)

AG
Opinion of the United States Court of Appeals

‘across the roller in order to effect a realignment. The
ultimate object of the Peterson device is to cuide the filter
belt in a smooth condition back to the drum for the pur-
pose of covering all of the surface exposed to the Vacuum.

The trial court found that this element with the resil-
ient means or springs attached to the guide rollers in
position so that the rollers bear against the beads of
the filter belt to tension and center the belt, as claimed
in the Petérson patent, was not found in any of the prior
art patents cited by the patent office during the prosecu-
tion of the Peterson application nor in any additional prior
art cited by Eimco. Eimco does not question this finding.

The Eimeo filter belt aligning mechanism is similar to
that described in the Peterson patent. In operation the
mechanism is mounted: on both sides of the belt at a posi-
tion between the rollers in the discharge seetion of the
filter machine, or between the drum and the first roller,
but not on the end of any roller. In some instances the
guide wheels bear against the beaded edge of the belt only
on the side that is in need of adjustment, but the contact
relation between these two elements is substantially the
same as that of the Peterson device. Eimco urges that
the function of its device differs from that of Peterson in
that its location between. the rollers utilizes the principle
of ‘‘planar action’’ in its operation, while the function of
the Peterson patent is to cause a slippage or sliding of
the belt across one of the rollers to. obtain realignment.
The spring tension necessary to obtain realignment when
the device is positioned between the rollers is much less
than when it is.mounted on one of the rollers. It is not

A7
Opinion of the United States Court of Appeals

contended that the belt realignment result obtained is
different in either instance. 7

The principal i issues presented by Eimco are that the
. trial court erred ‘in not holding the Peterson patent in-
_valid, for failure to mect the tests of non-obviousness
required by 35 U.S.C. 103, non-infringement, and a file
wrapper estoppel. |

A patent is presumed to be valid and this’ presumption
can be overcome only by clear and convincing evidence.
Griswold v. Oil Capital Valve Co., 10 Cir., 375 F. 2d 532;
King-Sceley Thermos Co. v. Refrigerated Dispensers, Inc.,
10 Cir., 354 F. 2d 533. Likewise, one asserting invalidity
of a patent on the ground of anticipation has the same
burden of proof. Griswold v. Oil Capital Valve Co., supra;

McCullough Tool Co. -v. Well Surveys, Inc., 10 Cir:, 343

F. 2d 381, cert. denied, 383 U. S. 933; Mott Corp. v. Sun-
flower Industries, Inc., 10 Cir., 314-F. 2d 872.

Generally, when elements old in the art are combined
together in a manner which secures a new and useful
result.or an old result in a more facile, economical and
efficient manner, there is a patentable combination. iMc-
Cullough Tool Co. v. Well Surveys, Inc., supra; Oliver
United Filters, Inc. v. Silver, 10 Cir., 206 RP 2d 658, cert.
* denied, 346 U. S. 943.

Utility, novelty, and non-obviousness are separ ate tests
of patentability and all must be satisfied for a valid —
United States v. Adams, 383 U. S. 39.

_ The utility of the Peterson combination is not ques-
tioned, and Eimco recognizes that the use of the spring
tension device to urge the guide wheels outwardly to align

~ entre 9

A8
Opinion of the United States Court of Appeals

the filter belt as it progresses in the filtering eycle was
not in the prior art. It contends, however, that the valid-
ity of the patent eannot be upheld on any single essential
element, but that patentability must be determined on
whether the combination as a whole would have been ob-
vious to a worker having ordinary skill in the art at the
time the alleged invention was made. This is a statutory
law, and the law of this Cireuit. 35 U.S.C. 103;* see Graham
vy. John Deere Co., 383 U.S. 1;> Mott Corp. v. Sunflower
Industrics, Inc. supra. The trial court found that the
prior art called to its attention, and the testimony of
Eimco’s expert witness to the effecexhat the substitution
of a resilient means for a non-resilient means of tracking
a filter belt was within the skill of the worker in the
art, ‘‘did ‘not overcome the indications in the record ‘to
the contrary and the presumption of the validity attaching
to the patent.”’ | -
Eimco’s objection to this. finding as we understand it,
is that the trial court, in determining the ‘‘nan-obvious”’
requirement, limited its inquiry to Eimco’s failure to

4. 35 U.S.C. 103 provides: “A patent may not be obtained
though the invention is not identically disclosed or described as set
forth in Section 102 of this title, if the differences between the sub-
ject matter sought to be patented and the prior art are such that the
subject matter as a whole would have been obvious at the’ time the

invention was made to a person having ordinary skill in the art to.

which: said subject matter pertains. Patentability shall not be nega-
tived by the manner in which the invention was made.” ~

5. 383 U.S. 19. With reference to the purpose of Sec. 103 the
Supreme. Court said : “Although we conclude here that the inquiry
which’the Patent Office and the courts. must make.as to the’ patenta-
bility must be beamed with the greater intensity on the requirements
of Sec. 103, it bears repeating that we find no change in the general
strictness with which the overall test is to be applied.”

"AQ
Opinion of the United States Court of Appeals

establish the lack of novelty required by Section 102. It
is urged that utility or novelty are not necessary criteria —
in the determination of the Section 103 requirements. Ob-
viousness is not to ‘be determined by the lack of utility
or nov elty, but oie of the factual tests contemplated by
Section 103 is a comparison between the subject matter
sought to be. patented and the prior art in, reaching a
conclusion as to obviousness or non-obviousness under the
statutory standards. In the Graham ease the court said:

‘‘We believe that this legislative history, as well
as other sources, shows that the revision was not in-
tended by Congress to change the general level of

atentable invention. We conclude that the section was
~~~ Intended merely as a codification of judicial precedents
embracing the Hotchkiss condition, with congressional
directions that inquiries into the obviousness of the
subject matter sought to be euecie are a prerequisite
to spencers
‘‘Approached in this light, the Section 103 addi-
tional condition, when follow ed realistically, will per-
mit a more practical test of patentability. -The em-
phasis on non-obviousness is one of inquiry, not qual-
jty, and, as such, eomports with the constitutional
strictures. . .
‘*While the ultimate question of patent validity is
one of law, A. & P. Tea Co. v. Supermarket Corp.,
- supra, at 155 (340 U.S. 147), the Section 103 condi-
tion which.is but one of three conditions, each of
which must be satisfied, lends itself to several basic
factual inquiries. Under Section 103, the scope and

\

content of the prior art are to be determined; dif- -.

ferences between the prior art and the claims at issue
“are to be ascertained; and the level of ordinary skiH

A10

Opinion of the United States Court of Appeals .

in the pertinent art resolved. Against this background,

_ the obviousness or non-obviousness of the ‘subject mat-

ter is determined.’’ See also Carson v.. Bland, 10

Cir., 398 F. 2d 423.

In determining the Section 103 issue the trial court
made the inquiry as to the obviousness or non-obviousness
of the subject matter as suggested by the Supreme Court.
The determination of non- obviousness was not limited to
a finding of lack of novelty. This is illustrated by a ref-

erence in its finding to the testimony of Eimco’s expert °

witness ‘and indications in the record to the.contrary.

The trial court’s complete. and careful findings disclose
' that for the purpose of ascertaining whether the Peterson
device would be obvious to a person having ordinary skill
in the art, it measured the device with the prior art to-
gether with ‘the record as-a whole. As indicated in the
Graham case, obviousness ‘‘to a-person having ordinary

skill in the art’” is an illusive factual subject to be deter-

' mined by the trial court. In recognizing the difficulties of
Section 103 .problems, the court warned that ‘‘what is
obvious is not a question upon w hich there is likely to be
uniformity of thought in every given context.. The diffi-
culties, however, are comparable to those encountered
- daily by the courts in such frames of reference as negli-
gence and s@@gpiter, and should be amenable to a case by
case development.’’ . The difficulties referred to are ques-
tions of fact to be determined in the trial court. The
courts agree that the ‘ultimate question of validity is one

of law, Griswold v. Oil Capital Valve Co., supra, but ob-

viousness as referred to in Section 103 is a question of

All

Opinion of the United States Court of Appeals

fact for the trial court, which determination should not
be set aside in the absence of clear error. Graver Mfg.
Co. v. Linde Air Products Co., 336 U. 8S. 271; McCullough
Tool Co. v. Well Surveys, Inc., supra; Maytag Co.-v. Mur-
ray Corp..of America, 6 Cir. 318 F. 2d 79. In Admiral
Corp. v. Zenith Radio Corp., 296 F. 2d 708, we said: ‘On -
conflicting evidence the trial court held that the devices
covered by the Zenith patents would not have been obvious
to one of ordinary skill in the art. This is a finding of
fact which cannot be set aside as clearly erroneous.’’ The
finding of non-obviousness is amply supported by sub-
stantial evidence, and we agree with the trial court that
the presumption of validity has not been overcome. We
find no language in Graham v. John Deere Co.,.supra, that
requires a different approach to the non-obvious question
than that made by the trial court, or that is contrary to
our former decisions.

On the question of infringement, Eimco insists that
its belt centering device is. not within the teaching of the
Peterson patent. It argues that the claims of the patent
and the specifications restrict the mounting of the belt
aligning device to the ends of the return roller; therefore,
its mechanism, which in operation is mounted only be-
tween rollers at various unsupported expanses of the belt,
is not an infringement. The Eimco device -is in all re-
speets similar to that’ claimed in the patent, including
guide rollers with springs attached to them. In opera-
tion, the Eimco mechanism is located at places other than
at the end of a roller, and the direction of the belt is
changed by pressure of the guide wheels against the

A12
Opinion of the United States Court of Appeals

beaded edges before it reaches the roller... But as the
belt approaches the rotating drum its alignment is the same
as that resulting from the action of the Peterson device.

The trial court, after a consideration.of all the evi-
dence, observing a demonstration of a model designed from
the Peterson model, and viewing the Eimeo apparatus
in actual operation, found: |

“While defendant’s apparatus with guide’ rollers
at locations other than’ that between the return roll
and the preceding idler roll do not meet the literal
terms of the claims, in that they were not mounted
adjacent the ends of the return roller, the guide rollers
at other locations in the path of travel of the belt
perform substantially the same function as guide roll-
ers mounted between the return roll and the idler
roll. That function is to correct mistracking of the
filter belt to track the belt back to the filter drum and
center it with respect thereto, and to stretch the belt
beween opposed pairs of guide rollers.

‘‘Tn all positions between rolls or the drum and in ,
the path of travel of the belt, the guide rollers per-

6. The trial court in its findings described the Eimco mechanism
in operation as follows: “The sn» eng aligning devices have
been located on its filters in every inStance in a position at an other-
wise unsupported ‘span of the filter web. In no instance has Eimco’s
aligning device been mounted laterally adjacent the end of the return
roll or any other roll. In most instances on the defendant’s three;
roll system, defendant’s aligning device is located between the filter
drum and the discharge roller. In a few instances, the defendant’s
aligning device has been located betwee? the return roller and the
next preceding roller in its three-roll system. In all instances in de-
fendant’s two-roll system, defendant’s aligning device has been lo-
cated between the filter drum and the discharge roller. In all in- -
stances in defendant’s five-roll system, defendant’s aligning device
has been located between the filter drum and the discharge roller
Defendant’s guide rollers do not contact the filter belt when the belt
is in contact with a roll, such as the discharge roll or return roll.

A138 |
Opinion of ime United States Court of Appeals

form their fatioting § in substantially the same way as
guide rollers mounted between the return roll and
idler roll. The mode of operation is the same, i.e., to
laterally displace the filter belt to one side so that
the belt will track by planar motion on to the follow-
ing roll in the path of travel of the belt. When the
guide rollers contact the filter belt while-the belt is
Jin. contact with the return roll or any - ll other ‘than
the filter drum, the rollers still act to move the belt
laterally by digo and.-the belt then tracks by
planar motion on the next roll in its path of move-
ment. Since the primary object of the invention and
the accused device is the centering of the stretched
filter medium on the drum, the court regards the
precise location of the guide rollers with reference to
the rollers as incidental; and particularly with ref-
erence to. the centering ofthe filter medium on the
filter drum the devices operate in substantially the
same way and perform substantially the same fune-
tion to accomplish substantially the same result. More-
over, it is found that any difference in location of the
guide rollers between the patented device and the
aceused device would be an equivalent vartation which
would be obvious to one possessing ordinary skill in
the art.’’

The court also found that there was no teaching in the
patent disclosure ‘‘that the return roll must be in econ-
tact with the belt at the same time that the guide rollers
exert tension across the Delt’? for a proper functioning
of the patented device.

The law of infringement applicable to this. ease was
stated by this court in King-Seeley Thermos Co. v. Re-
frigerated Dispensers, Inc., supra, as follows:

Al4
Opinion of the United States Court of Appeals

‘‘Infringement is not avoided by making a machine
which differs in form but appropriates the principle
and mode of operation of the patented machine by the
use of the same or equivalent means. Janco, Ine. v.
Carlson, supra; Jones v. Bodaness, 10 Cir., 189 F. 2d
838; Stearns-Roger Mfg. Co. v. Ruth, 10 Cir., 62 F. 2d
442; Johns-Manville Corp. 'v. National Tank Seal Co.,
10 Cir., 49 F. 2d 142. Infringement exists if the
accused device performs substantially the same fune-
tion in substantially the same way and accomplishes
substantially the same result as the patented device, :
even though they differ in name, form and shape.
Graver Tank & Mfg. Co. v. Linde Air Products Co.,
339 U. S. 605, 70 S. Ct. 854, 94 L. Ed. 1097, reh. denied
340 U. S. 845, 71 S. Ct..12, 95 L. Ed. 620. If the
“accused machine falls clearly and definitely within
the claim of a patent, infringement is made out. Mce-
Cullough Tool Co. v. Well Survey, Inc., supra. “The
protection of the provisions of a patent cannot be
avoided by adding materials unléss a wholly differ-
ent result is obtained. ‘Colorable differences without
substance do not avoid infringement.’ Bewal, Ine. v.
Minnesota Mining and Mfg. Co., supra, 292 F. 2d at
167. Cf. Reiner v. I. Leon Co., 2 Cir., 285 F. 2d 501,
cert. denied 366 U. S. 929, 81 S. Ct. 1649, 6 L. Ed.
2d 388, reh. denied 366 U. S. 978, 81 S. Ct. 1918, 6

iL. Ed. 2d 1268.”’

The evidence is without substantial conflict that the

place of applying force to the edges of the filter belt and
the alignment resulting: from the use of the Eimco equip-
ment is the same as that of the patented machine regard-
less of where it is placed on the structure over which the

belt passes. We agree with the trial court that the placing

Ald
Opinion of the United States Court of Appeals

of the equipment between rollers or between the drum and
the discharge roller is inconsequential and is merely a
substitution of equivalents. The Eimco machine wherever
it is placed on the belt uses the same principle and mode
of operation as the one described in the Peterson patent.
The two devices do thé same work in substantially the
same way and produce substantially the same result. This
is the test of infringement, as indicated in King-Seeley
Thermos Co. v. Refrigerated Dispensers, Inc., supra, and -
the cases cited therein.

Finally, Kimco contends that the ‘‘file wrapper’? his-
tory of the Peterson patent discloses that to#obtain his
patent, Peterson explicitly limited the mounting of his belt
realignment. device to a particular point ‘‘adjacent: to
each end of the return roller’? and cannot now expand
that language to encompass alignment apparatus posi-
tioned between rollers such as that used by Eimco. The
law is settled that the extent of an invention is to be
determined by the patent claims, together with the ‘‘file
wrapper’’ history in the Patent Office, and a claim which
has been narrowed for the purpose of obtaining the patent
cannot be expanded to include that which was eliminated.
Graham v. John Deere Co., supra. The application of this
doctrine, however, is limited to changes made to overcome
rejections by the Patent Office far the reason that the
claim was anticipated .in prior art similarities. It is not
applicable where the patentee encountered difficulties in
the Patent Office because of particular wording and indefi-
— nitetiess of the claims. McCullough Tool Co. v. Well Sur-
veys, Inc., ‘supra; Sears Roebuck & Co. v. Jones, 10 Cir.,
308 F. 2d 705.

A16
Opinion of the United States Court of Appeals

When the Peterson application was filed it contained
seventeen claims. The first thirteen were directed to a belt
aligning mechanism as illustrated in ‘the Peterson patent.
The original claims 1 to 10 naar that the mechanism
was to be mounted or positioned fdjacent to the filter
drum. Original claims 11 and 12 provided for two single
‘‘hbead contacting rollers”’ pehiieh were ‘‘juxtaposed to
‘the ends of the return roller and arranged to move lat-
erally opposite one another to guide and stretch the web
in cooperation with the return roller’’. All of the original
claims were rejected by the Patent Office for the reason
that they were indefinite and directed to an old combina-
- tion. Peterson then canceled claim 13.and amended claims
1 to 12. These claims were again rejected for indefinite-
ness and as unpatentable over the prior art. In response
to this rejection, Peterson canceled all of his claims and
substituted in. their place claims 18 and. 19, which are
now claims 1 and 2. It is argued that to overcome the
rejections of the aforesaid claims, Peterson provided that
his roller system for aligning the filter belts would be
mounted adjacent each end of the return roller’’. It iS
said that to permit the positioning of the Peterson device
in any other location, particularly between rollers, would
‘allow him to recover and include in his patent that which
he exeluded to obtain it.

An expert witness, after analyzing the Patent Office
records, testified that the term ‘adjacent each.end of the
return roller’? was inserted in the claims for clarifying ’
language and not for the plirpose of overcoming a Patent
Office objection on the prior art. The witness also said

~

Al7 | °
Opinion of the United States Court of Appeals

that when Peterson used the term he could have instead
appropriately and reasonably said ‘‘by means of rollers
mounted adjacent to the outer edge of the filter medium”’.

The trial court found that the critical phrase was in-
cluded in the patent to overcome a Patent Office rejection
because ¢he language of the claims.was indefinite and mis-
descriptive, and not to. avoid a rejection on the prior art.‘
The record sustains these findings.

AFFIRMED. |

7. The trial court’s findings on the question of “‘file wrapper”
estoppel included the following :

“From the testimony of Burns, plaintiffs’ expert, and an ex-
amination of the file wrapper of the Peterson patent, I find that
the Examiner meant by this rejection that the guide rollers could
not be in line with the center of the filter drum because in the
drawings and the specification the guide rollers were disclosed _
as near the outer edges of the drum and that such a position is
necessary in order for the guide rollers to contact the beads on
the outer edges of the belt. In Paper No. 5 the Examiner said
that the rollers were shown “adjacent” the outer edges of the
drum. The applicant responded to this rejection by locating the
rollers adjacent the ends of the return roll, which, with respect
to the filter belt is the same location as the outer edges of the
drum.

“In Paper No. 5 the Examiner also rejected claims 1 to 12 as
unpatentable over U. S. Patent No. 2,880,875 to Alston in view
of British Patent No. 812,197 or vice versa, and claims 14 -to
16 as fully met by the British patent. , The phrase “adjacent each
end of the return roller” was not placed in claim 18 (claim 1
of the patent) to meet this basis of rejection on the prior art.

. There is no indication that in this rejection on the prior art the
Examiner required claim language that the guide rollers be
-mounted laterally adjacent the ends of the return roller as con-
trasted with being mounted longitudinally adjacent the ends of
the return roller.”

A18

Findings of Fact and Conclusions of Law

IN THE
UNITED STATES DISTRICT COURT
For tHe District or UTan |

CENTRAL DIvIsIon

No. 030-66

——E— a

PETERSON FILTERS AND ENGINEERING CoMPANY and KoMLINE-
SANDERSON ENGINEERING CORPORATION,
Plaintiffs,
US.

THe Ermco Corporation, .
reas Defendant.

This case has been tried to the court, orally argued by
counsel, submitted for decision upon written briefs, and by
the court taken under advisement. Now considering itself
fully advised, the court makes and enters the following

Finpincs or Fact

Nature of Action

1. This is an action for infringement of United States
Letters Patent No. 3,077,990 granted-February 19, 1963, to
John G. Peterson, as assignor to Peterson Filters and En-
gineering Company, for Filter Medium Guide.

.

A19
Findings of Fact and Conclusions of Law

Parties

"9. Plaintiff, Peterson Filters and Engineering Com-
pany (hereinafter ‘‘Peterson’’), is a Utah corporation hav-
ing its principal place of business in Salt Lake City, Utah.

3. Plaintiff, Komline-Sanderson Engineering Corpora-
tion (hereinafter ‘‘Komline’’), is a New Jersey corpora-
tion having its principal place of business in n Peapack, New
Jersey.

4. Defendant, The Eimco Corporation (hereinafter
‘‘Kimeo’’), is a Delaware corporation having a regular
and established place of business in Salt Lake City, Utah.

Status of Plaintiffs

D. Plai Peterson is now and since February 19,
1963, has been the owner of United States Patent No. 3,-
077,990 in suit. 7

6. Plaintiff Komline is now and since July 12, 1965,
has been the exclusive licens¢e under United States Let-
ters Patent No. 3,077,990 in suit in the ‘‘sanitary field’’,
which has also been defined as the ‘‘municipal sewerage
treatment field’’. Pursuant to its license agreement with
Peterson, Komline has the unrestricted right to bring suit
under United States Letters Patent No. 3,077,990 for as-
serted infringements thereof which oceur only in the ‘‘sani-

tary field’’, that is, the “municipal sewerage treatment
field’? and the restricted right ‘‘for a period of one year
from the date of the agreement’? to institute suit or suits

A20
_ Findings of Fact and Conclusions of Law

_ against a third party for asserted infringement that ex-
tends ‘‘into other than the municipal sewerage treatment

field’’.
*

Subject Matter of Litigation

7. This litigation is concerned with a particular filter
web or belt aligning mechanism or device for use with one
type of rotary drum vacuum filter employed in separating
solids from liquids, namely, a continuous filter medium re-
- moval drum filter, sometimes referred to as a belt discharge
filter, or a drum filter ‘‘having a separate cake discharge
section’’. The belt discharge filter includes a filter drum
—a cylindrical member having closed ends that varies in
diameter between eighteen inches and fourteen feet and in
face width between one and fourteen feet. The drum has
a perforated deck surface which, in operation, is covered
for the greater part of its periphery by a filter. medium or
web. The perforated deck is connected by pipes to an auto-
matic rotary, valve. A portion of the drum covered by the
filter medium is immersed in a tank containing slurry and
rotated. By means. of the rotary valve, a vacuum is pulled
on the underside of the filter drum while it is immersed in
the slurry and for a short period thereafter. The liquid
phase of the slurry is drawn through the filter medium to
the interior of the drum and the solids are deposited on
the surface of the filter medium. As the drum rotates, the
filter medium on which the solid material has been depos-
_ited leaves the slurry and, as the drum continues its rota-
tion, the filter medium is withdrawn from the perforated
surface of the drum and passes over a roller called a dis-

A21
Findings of Fact and Conclusions of Law

charge roller. At the discharge roller an abrupt change
in the dir ection of travel of the filter medium causes the .

gk to fall off the medium. The filter medium or belt then |

passes (a) directly to the return roll (two-roll system), or
(b) over one or more wash or idler rolls and thence to the
return roll (three and five roll systems). From the return
roll the medium passes directly back to the drum, where it
again engages the perforated deck of the drum for a rep-
etition of the filtering cyele. |

8. In normal operation a filtet belt which is part of a
rotary vacuum drum filter apparatus tends to track lat-

erally to the left or right’ and, if not corrected, will mis-

track on the filter drum and expose some of the perforated
area of the drum that should be covered by the belt. When
this occurs, the raw slurry in the tank will be drawn into
the filter drum and then the pipes and valves therewithin.
The filtrate will be contaminated and eventually the filter
will become inoperative.

9. Mistracking occurs for many reasons, such as the
practical impossibility of manufacturing a filter drum hav-
ing perfect symmetry, misalignment of one or more of the
rolls of the filter apparatus, variations in the load of filter
cake carried by the belt, and incomplete discharge of filter
cake from the belt. Because of these variables, the belt.
can mistrack to either side of the drum. 2

10. It is most important that the filter belt be sufti-
ciently aligned so that no portion of the drum perforations

A22
Findings of Fact and Conclusions of Law

- are exposed to the raw slurry. It is not desirable that mis-
alignment occur at other locations of the filter apparatus,
but moderate misalignment at rolls such as the return roll
will not substantially impair operation of: the apparatus
to the extent that it does not affect the positioning of the .
filter medium on the drum. .

11. Wrinkles often occur in a filter belt made of cloth.
Wrinkles occur in most rotary vacuum filter apparatus em-
ploying cloth belts. Lack of proper alignment of the belt
when it is being fabricated is one cause of wrinkles.

Disclosure of the Peterson Patent in. Suit

_ 12. U.S. Patent No. 3,077,990 to Peterson has for its
object avoiding wrinkling in the filter belt and tracking the
belt properly back onto the filter drum: The endless belt
_ is provided with continuous beads at opposite side edges
thereof and\passes over the filter drum and then, in its
path of travel, over a discharge roll, two idler rolls, a re-
turn roll, and then back onto and around the drum. The
. Peterson patent discloses guide rollers as part of the ap-
paratus, one pair of guide rollers bearing against a bead
at each side of the belt to urge the belt outwardly on each
side by’its lateral stretching and thus smooth out wrinkles
in. the belt. Figures 3, 4 and 6 of the drawings show and
the specification discloses resilient means in the forms of
springs which are attached to the two pairs of guide rollers
and continuously urge the rollers away from the center
line of the belt. By the use of such resilient means the belt
is automatically centered with respect to the filter drum

A23
Findings of Fact and Conclusions of Law

and mistracking with respect to the drum is automatically
corrected. |
f ;

13. Of the figures of the drawings that show a resili-
ent means or springs for correcting mistracking of the
belt, Figurés 4 and 6 show both the guide rollers and the
return roll. In each of Figures 4 and 6 the guide rollers
are in contact with the beads at the side edges of the belt.
while the belt is also in contact with. the return roll. In
Figure 3 of the drawings no return roll is illustrated, al-
though the filter drum is shown. The specification states
that the return roll is not shown in Figure 3 and there is
no statement in the specification that the return roll must
be-in contact with the belt at the-same time that the guide
rollers exert tension across the belt. There is no teaching
in the patent disclosure that any such relationship is nec-
essary in order to have -the guide rollers function prop-
erly, and I find that no such relationship is necessary.

14. The filter belt cannot first contact the filter drum
at a position at the bottom of the drum when the drum is
rotating with its axis in a substantially horizontal plane.
Such contact would leave portions of.the perforated drum
surface exposed to raw slurry in the tank before: the belt
contacted the drum. Instead, the belt must contact’ the
_ drum at a location prior to contact with the tank slurry.
- A eonventional example of belt-drum contact is shown in
Figure 1.

_ 16. Figures 1 and 3 are stated to be schematic draw-
ings. In Figure 3, for convenience of illustration, the

A24
Findings of Fact and ‘Conclusions of Law —

drawing shows the filter drum directly over the filter belt
if the view is a side elevational view. Since such a posi-
tion would. not’ be operable, it is apparent that the illus-
tration of Figure 3-is not a side elevational view.

16. According to testimony of plaintiffs’ expert witness
and the inventor, other figures, such as 2, 4 and 6, illus-
trate the apparatus with the filter belt in contact with the
return roll in any position between the point of tangency
of the filter belt when it first contacts the return roll and
the point of tangency when the filter belt leaves the re-
_turn roll. Defendant’s expert witness did not deny that
the drawings could show this relationship. In those fig-
ures where the guide rollers act. on the belt while the belt
is in contact with the return roll, neither the specificaticn
nor the drawings limit the relationship of the belt and re-
turn roll to a position in which the filter belt is directly
atop the return roll.

The Patent Claims

17. The patent in suit contains two claims, the second
of which is written in dependent form and incorporates
the recitations of the first by reference. Claim 1 is writ-
ten in a form in which the general apparatus already known
to the art is first ‘set forth, and then the improvement is
recited in terms that relate back to and specifically men-
tion those parts of the apparatus that are known. . It was
agreed by witnesses for both parties that the preamble of
the claim recites apparatus known to the art.

A25

Findings of Fact and Conclusions of Law

18. The improvement claimed by the patentee is means :

for tracking the filter medium back to the filter drum. It
includes two pairs of guide rollers mounted adjacent each

end of the return roller with the filter: medium between |

- them and arranged to move laterally across the path of
travel of the filter medium and to bear against the beads
at the edges of the filter medium or belt. Resilient means
are recited as being attached to the guide rollers so that

the rollers bear against the beads to stretch the filter me--

dium and to center it in relation to the return roll and the
filter drum. There are means supporting each pair of

rollers. Claim 2 is essentially the same as claim 1 except |

that the resilient .means are specifically described as
springs. The filter medium aligning, stretching and ten-
sioning device disclosed and described in patent in suit No.
3,077,990 and claimed in claim 1 thereof comprises, in com-
bination, essentially and more particularly five structural
components or elements, to wit: .

(1) a return roller

(2) a filter medium having ‘‘beaded edges”’

(3) two pairs of guide wheels (or rollers)

(4) resilient web tensioning devices, such as springs

(5) mounting means for the guide wheels (or roll-
ers)

and the following specific directives or requirements
for the assemblage of these structural components to
achieve particular and specified functions, to wit:

(6) Each of the two pairs of rollers are to be
_ mounted

STR N Oy MPI TOR

A26

Findings of Fact and Conclusions of Law

(a) one adjacent each end of the return roller
(b) in substantial contacting relation
(c) with the filter medium ‘therebetween

(d) in a position to bear against the bead at each
edge of the filter medium, and

(e) arranged to move laterally in respect: to the
path of travel of the web. _

(7) The resilient means (springs in claim 2) are to
be attached to said guide wheels (rollers) in position
so that the guide wheels (rollers) bear against the bead
at each edge of the filter medium to .

(a) stretch the filter medium therebetween and

(b) center it with respect to the return roller and
the filter drum.

(8) The mounting means for the guide wheels (roll-
ers) are to comprise means to support each pair of
guide wheels (rollers)

(a) in‘position on the filter medium and

(b) biased against the adjacent bead at the edge
thereof. ps

é
The Validity Issue

19. This court finds that the element and its function ~
of the apparatus claimed in the Peterson patent, which is
not found in any of the prior art patents cited by the Pat-
ent Office in the course of the prosecution of the Peterson
application or any additional prior art cited by defendant,
is the resilient means or springs attached to the guide roll-

A27
Findings of Fact and Conclusions of Law

ers in position so that the rollers veer against the —
of the filter belt to tension and center the belt.

20. The only patent referred to by defendant at the
trial that shows or describes any springs or resiltent means
is U. S. Patent No. 2,880,875 to Alston, which was cited
by the Patent Office. Alston discloses coil springs secured
to eyelets on a filter belt, not to guide rollers. The filter

belt of Alston sags and forms a liquid-receiving basin with-

a weight such that the belt is further supported by a metal,
open-mesh belt beneath it. The springs of Alston function
to reduce stress on the belt due to weight of liquid when
the belt has sagged to form a basin-like structure. Both
expert witnesses testified that the springs of Alston did
not act to center or correct mistracking of the filter beit
of Alston. There is no disclosure in the prior art of coil
springs having the function of those in the patent in a
similar combination of elements. | :

21.. There is no suggestion in the prior art brought to
the attention of the Court that the coil springs of Alston
-ean be attached to guide rollers of an apparatus such as

that of the Peterson patent and used in the manner in which

; they are used in the patented apparatus. Alston is not
in the field of rotary vacuum belt filters and no vacuum is
applied. One of ordinary skill in this art would not find it
obvious to use coil springs in the manner of the patented
apparatus. None of the prior art shows any resilient means
attached to guide rollers to center a filter belt with respect
to a filter drum and to apply tension to the belt.

Sat Ban, a Bad Ate ok Poe

A28 .
Findings of Fact and Conclusions of Law

99. Defendant’s expert witness, Weems, national sales
manager of the defendant corporation, testified that sub-
stitution of resilient means for non-resilient means. in the
prior art would be within the skill of the art although a
change in function accompanied the substitution. The court
is of the opinion that this opinion did not overcome the in-
dications in the record to the contrary and the presumption
of validity attaching‘to a patent. No prior art was brought
forth by defendant to show the obvious nature of the

claimed apparatus and its function; while the Allis patent

and the Koppehele patent were not considered by the
patent office, the court is of the opinion that they separately
or in combination did not disclose the plaintiffs’ invention

- and that representative of each group of prior art patents

which defendant alleges anticipates an element of the plain-
tiffs’ apparatus is a patent cited by the U. S. Patent Of-
fice against the Peterson application.

93. Plaintiff Peterson has never made -a commercial
embodiment of an apparatus according to that claimed in
the patent in suit. Plaintiff Komline has concluded con-

tracts of sale with Bechtel Corporation and Kawaecki

Chemical Corp. for rotary vacuum belt filters employing the
claimed apparatus. Requests for or inquiries concerning
a license under the patent in suit have been made by two

other companies that are substantial factors in, the sanitary

field. Of the five companies that are substantial factors
in the field, excluding the defendant, only one has not
sought a license under the Peterson patent.

24. As of (a) the date on which John G. Peterson
filed the application for the patent: in suit, March 7, 1960;

A29
Findings of Fact and Conclusions of Law

_(b) the date on which the patent in suit was granted, Febru-
ary 19, 1963; (c) the date on which Peterson granted a
. license under the patent in suit ito Komline, July 12, 1965;
(d) the date on which this action was instituted, February
23, 1966; and (e) the date on which the trial of the action
was'concluded, May 17, 1967; neither plaintiff had ever in-
stalled any apparatus for commercial use embodying the
subject matter of the patent*in: suit. Defendant did not
meet its burden of showing bg clear and convincing evi-
dence that the apparatus of the Peterson patent is inopera-
tive. Plaintiffs produced for demonstration purposes at
- trial a small but commercial rotary vacuum belt filter ac-
- cording to the Peterson patent. The guide rollers of the
filter were movable to various locations in the path of

travel of the filter belt. In the position substantially as:
shown in Figure 6 of the drawings, the apparatus was |

operative. Defendant’s expert witness testified. that the
unit was operative with a filter medium of the type having
coil springs within envelopes at the edges of the medium.
These envelopes are beads within the scope of the Peterson
patent.

The Infringement Issue .

25. Defendant . Kimco manufactures and sells, inter
alia, rotary vacuum belt filters which are utilized by de-

fendant’s customers in the separation of solids from the ~

liquid phase of slurries. Defendant sells to customers in
the sanitary field and in the industrial field.

26. The filter medium or belt which is utilized on Kimeco
filter apparatus is maintained in alignment with the filter

OS A RR TN Rem gE ga
\ s

pe

A30
Findings of Fact and Conclusions of Law

drum by means of beaded belt edges that cooperate with
pairs of guide rollers having resiltent springs attached to
- them to effect alignment of the filter belt on the drum.

27. Defendant manufactures and sells rotary vacuum.
belt filters in which guide rollers having springs attached
to them as claimed in claims 1. and 2 of the Peterson patent
are positioned at various locations along the path of travel
of the filter belt. In-some machines two opposed pairs of
guide rollers are positioned at one location; in other
machines two pairs of guide rollers are at one location and
two other pairs at another location of the filter belt. -

28. In a typical accused apparatus of defendant com-
prising a filter drm and, in order of travel of the filter
belt from the drum, a discharge’ roll, an idler roll, a return
roll, and then the drum, again, defendant has located its
pairs of guide rollers having springs attached thereto to
eenter and track the filter belt -in all positions except be-
tween the return roll and. the filter drum. Due to the
structure of the apparatus, access to guide rollers mounted
other than between the filter drum and the discharge roll is
difficult because of interference by the frame of the ap-
paratus and installation of auxiliary equipment. However,
a letter sent by a regional sales manager of defendant
states that it became standard with Eimco to place its guide
rollers, referred to as Edgetrack rollers, between the idler
roll and the return roll.

29. The Kimco Edgetrack aligning devices have been
located on its filters in every instance in a position at an

“~e.

A31

Findings of Fact and Conclusions of Law

otherwise unsupported span of*the filter web. In no in-
stance has EKimco’s aligning device been mounted laterally
adjacent the end of the return roll or any other roll. In
most instances on the .defendant’s three-roll system, de-
fendant ’s aligning device is located between the filter drum
and the discharge roller. In a few instances the defend-
ant’s aligning device has been located between the return -
roller and the next preceding roller’in its three-roll system.
In all instances in defendant’s two-roll system, defendant’s
aligning device.has been located between the filter drum
and the discharge roller. In all instances in defendant’s
five-rolI system, defendant’s aligning device has been
located between the filter drum’ and the discharge roller.
Defendant’s guide rollers do not contact the filter belt when
the belt is in contact with a roll, such as the discharge
roll or return roll. |

30. The claims of the Peterson patent locate the guide :
rollers adjacent the ends of the return roll. Defendant’s
guide rollers have been located as close as nine’ inches
from the return roll and adjacent the ends thereof; but not
. laterally adjacent to such ends.

The File Wrapper of the Peterson Patent

31. According to standard dictionaries, the word ‘‘ad-
jacent’’ can mean either in the general vicinity of or in
' direct contact with. Adjacent is a broad term, and de-
fendant’s aceused apparatus with guide rollers located be-
tween the return rol] and the next roll iv the path of travel
of the filter belt (usually the idler roll) are adjacent the

A382
Findings of Fact and Conclusions of Law

ends of the return roll unless there is a teaching to the
contrary in the patent so as to limit the definition of ad-
- jacent, or unless its meaning is restricted by the doctrine
. of file wrapper estoppel. —

39. There is no teaching in the patent in suit that limits
the meaning of the word adjacent as used in the phrase
‘adjacent each end of the return roller’’ in claim 1toa
position laterally adjacent the ends rather than adjacent
the ends in the path of travel of the belt. There is nothing
in the disclosure of the’ patent that restricts the guide |
rollers to such a laterally adjacent position.

33. The application that resulted in the patent in suit
was filed March 7, 1960 in the U. 8. Patent Office with 17
claims. These claims were later cancelled and the two
claims that are presently in the patent in suit were added.

34. The phrase ‘‘adjacent each end of the return roller’’
first appeared in the claims in claim 18, which became
claim 1 of the patent in suit. Claim 18 was added to the ap-
plication by an amendment received in the U. S. Patent
Office on April 23, 1962 and designated as Amendment B.
Amendment B was filed in response to Paper No. 9, which
was an official action of the U. S. Patent Office mailed Octo-
ber 25, 1961.

35. The phrase ‘adjacent each end of the return roller”’
was added in response to a rejection of the former claims as
being ‘‘indefinite and somewhat misdescriptive.’? This
rejection was made in the official action designated Paper

A33
Findings of Fact and Conclusions of Law

No. 5. In that official action the Examiner objected to the
phrase ‘‘medium. engaging means being centered in rela-
tion to said filter drum,’’ which was present in claim 1, lies
10 and 11. The Kxaminer stated that this was contrary to
the disclosure of the application ‘¢* ® * wherein the medium
engaging means are shown adjacent the outer edges of the
drum rather than the center thereof.”’ .

36. From the testimony of Burns, plaintiffs’ expert,
-and an examination of the file wrapper of the Peterson
patent, I find that the Examiner meant by this rejection ,
that the guide rollers could not be in line with the center
of the filter drum because in the drawings and the specifica-
tion the guide rollers were disclosed as near the outer edges
- of the drum and that sucha position is necessary in order
for the guide rollers to contact the beads on the outer edges
of the belt. In Paper No. 5 the Examiner that said the
rollers, that were shown ‘‘adjacent’’ the outer edges of the
drum. The applicant responded to this rejection by lo-
eating the rollers adjacent the ends of the return roll,
which, with respect to the filter belt is the same location
as the outer edges of the drum.

_ *37. In Paper No. 5 the Examiner also rejected claims 1
to 12 as unpatentable over U. 8S. Patent No. 2,880,875 to
Alston in view of British Patent No. 812, 197 or vice, versa, -
and claims 14 to 16 as fully met by the British patent. The
phrase ‘‘adjacent each end of the return roller’’ was not
placed in claim 18 (claim 1 of the patent) to meet this basis
of rejection and thus was not inserted in order to avoid -

*
eae

e
ee

“A834
Findings of Fact and Conclusions of Law

a rejection on the prior art. There is no mdication that in
this rejection on the prior art the Examiner required claim
language that the guide rollers be mounted laterally ad-
sted with being

jacent the ends of the return roller

mounted longitudinally adjacent the ends of the return
roller.

38. The Examiner did not, in the rejection over a com-
bination of the Alston and British patents, require that the
guide rollers be claimed with respect to the return roll so as
to distinguish this prior art. In the British patent, the
guide rollers 3 contact the belt and the bead while the belt is
in contact with the rollers 2. The Alston patent shows no —
guide rollers in contact with a belt bead. Consequently,
locating the guide roller adjacent each end of the return
roller would not have obtained allowance of any claim be-
cause it did not distinguish the relative locations of the
rollers 2 and 3 of the British patent.

39, In making his rejection on the prior art in Paper
No. 5, the Examiner also said that the ‘** * * means for
stretching the edges of the belt of Alston is substantially
similar to the species of Figs. 3, 4 and 6 of applicant’s.
* * *»> Since the Examiner had stated that the prior art
was similar to species of these figures, and in Figures 4 and
6 the guide rollers are shown laterally adjacent each end
of the return roll, the phrase in question was not added to
issued claim 1 to avoid the Examiner’s rejection on the
prior art, because, in view of the Examiner’s statements,
such addition would haye been fruitless. This is borne out

-A35
- Findings of Fact and Conclusions of Law.

by the fact that in the Remarks accompanying Amendment
B, Peterson did not argue that the relative locations -of
the guide rollers and return roll avoided the prior art.

40. In claim 1 of the patent the word ‘‘adjacent’’ is
also used to define the relative locations of the return roll
and the filter drum. Clearly the return roll and the filter
drum in the Peterson apparatus are not in eontact with
each other and, are longitudinally adjacent in the path of
travel of the filter belt. The word ‘‘adjacent’’ in the
phrase ‘‘adjacent each end of the return roller’? can also
mean longitudinally adjacent in the path of travel of the
filter belt.

The Doctrine of Equivalence

41. While defendant’s apparatus with guide rollers
at locations other than that between the return roll and the
preceding idler roll do not meet the literal terms of the
claims, in that they were not mounted adjacent the ends
of the return roller, the guide rollers at other locations in
the path of travel of the belt perform substantially the
same function as guide rollers mounted between the return

roll and the idler roll. That function is to correct mis-. |

tracking of the filter belt, to track the belt back to the filter
‘ drum and center it with respect thereto, and to stretch the
belt between opposed pairs of guide rollers.

42. In all positions between rolls or the drum and in
the path of travel of the belt, the guide rollers perform their
function in substantially the same way as guide rollers

e

A36 °
Findings of Fact and Conclusions of Law

mounted between the return roll and idler roll. The mode
of operation is the same, i.e., to laterally displace the filter
~ belt to one side so that the belt will track by planar
motion on to the following roll in the path of travel of the
belt. When the guide rollers contact the filter belt while
the belt is in contact with the return roll or any roll other
than the filter drum, the rollers still act to yiove the belt
laterally by slippage and the belt then tracks by planar
motion on the next roll in its path of movement. Sinee the
primary object of the invention and the accused device is
the centering of the stretched filter medium on the drum,
the court regards the precise location of the guide rollers
with reference to the rollers as incidental; and particularly
with reference to the centering of the filter medium on the
filter drum the devices operate in substantially the same
way and perform substantially the same function to ac-
complish substantially the same result. Moreover, it is
found that any difference in location of the guide rollers
between the patented device and the atcused device would |
be an equivalent variation whith would be obvious to one
“possessing ordinary skill in the art. ‘In all positions be-
tween rolls or the drum and in the path of travel of the
belt, the guide: rollers accomplish substantially the same
result. In all such positions the guide rollers stretch the
filter medium between opposed pairs of guide rollers, cor-
rect mistracking of the filter belt and track the belt back
to the filter drum, centering it with respect to the drum.

— 438. In U. 8. Application Ser. No. 315,658, filed October
11, 1963 in the name of Steven ’S. Davis, an employee of

A37
Findings of Fact and Conclusions of Law

defendant, which application was. stated by defendant ‘to
constitute a written description of the accused apparatus,
the applicant indicated that the guide rollers may be
placed in any position between rolls, or between the filter
drum and a roll, and makes no distinction as to the opera-
tion or effectiveness of the guide rollers in suck positions.

44, At Monsanto Company’s John J. Quecny plant, |

St. Louis, Missouri, two of defendant’s three-roil filters
performing substantially the same operation were installed,
one with pairs of guide rollers located between the filter
drum and discharge roll, the other with pairs ‘of guide
rollers between the idler roll and réfurn roll. Defendant’s

expert also testified that the basic action at various loca- —

tions between rolls is the same.

45. By use-of the word “stretch”? in the claims and
disclosure, the Peterson patent refers to a tensioning of the
belt between opposed pairs of guide rollers.. The belt, it-

self, need not be pulled out of shape, since this would do

harm to the belt. Tensioning of the belt to. remove wrinkies
therein is one of the advantageous functions df the’ guide
rollers. Defendant’s device is designed to tension and
stretch its filter belts. .

Recent Chan'ges in. Defendant’s Apparatus

46. In reeent instances in EKimco’s Edgetrack device,
the guide rollers have been separated by a positive stop bar
to provide spacing equal to the thickness of the edging of
the web plus 1/64 inch and are designed to pull free ofthe
beaded edge of the belt when forces in excess of twelve

see ton yr er saRTS:

AS AER

a

A38
Findings of Fact and Conclusions of Law

pounds are applied thereto. Such variation still meets the
terms of the claims because the rollers are ‘‘in substantial
contacting relation.’? Spacing the upper roller 1/64 inch
above the upper surface of the belt makes no substantial -
difference in the essential function of the guide rollers ex-
cept by way of extent or degree.

47. On recent occasions defendant has modified its ap-
-—paratus in use so that one pair of guide rollers is set in-
wardly of its bead by about *4 inch. In connection with |
such use for about the first two days all.guide rollers are
‘ in contact with their respective beads and not set inwardly.
Both the Davis application and defendant’s instruction
booklets, which were said by defendant to be writings dis-
closing the accused apparatus, describe apparatus with
both pairs of guide rollers in contact with the beads of the
belt. However, even if one pair is set inwardly about
34 inch, conventional belt bias, if uncorrected, may result in
a diminution of effective belt width to bring the inset pair
of rollers into contact with their bead. Substantially the
same amount of tension would then be applied by both op-
‘posed pairs of guide rollers to their beads and the belt.

_ 48. No matter how defendant adjusts its guide rollers,
the rollers can easily be adjusted by defendant’s custom-
ers-to bririg them into contact with the bead and the de-
fendant’s apparatus in fact is designed, manufactured and
-arranged to readily permit and encourage the lateral ten-
sioning of the filter medium by the operation of two pairs
of rollers as taught by plaintiffs’ invention. Defendant’s

*

A39
Findings of Fact and Conclusions of Law

operating instructions teach sych bead-contacting adjust-
ment to the customer and are left’ with. the customer.
Adjustment wherein both opposed pairs of guide rollers
are in contact with the beads at each side of the belt is
advantageous ,in that it provides dewrinkling tension on
tlie belt not present when one pair of rollers is out of

contact with its bead. It also provides that a belt mis-

tracking toward either side or irregularly will be auto-
matically urged toward a position in which mistracking
is corrected and the belt centered with respect to the filter
drum, although there may be certain other disadvantages
as compared with a single pair of guide rollers operating
on one side only of the filter medium, sugh as decreased
wear or strain on the filter medium. The plaintiffs’ patent
in’ suit does not read on a single pair of guide rollers
designed to operate on one side or the other of the filter
medium and not to tension the belt laterally away from
another pair of guide rollers on the opposite side of the
filter medium. |

The Patent Misuse Issue

49. The assertion that plaintiffs have misused the —

patent in suit and must be,denied relief until such misuse
has been purged is based on a clause in paragraph V of
the License Agreement between. plaintiffs dated July 12,
1965. This clause gives licensee (Komline) ‘‘the right for
a period of one (1) year from the date of the agreement
to institute or bring any suit or suits for infringement
against a third party whose infringing activities extend
into other than the ‘municipal sewerage treatment field.’

a i |

A40
Findings of Fact and Conclusions of Law

In such event, the Licensee shall assume all the costs and
shall be entitled to the full amount of any recovery.’’.

50. Rotary vacuum belt filters are used in the sanitary
~ field (municipal. sewage) and industrial field (all other
applications). In the sanitary field, and specifically with
respect to dewatering of sewage sludges, plaintiff Kom-
line manufactures and. sells approximately two out of”
three filters, due primarily to sales of its coil spring filters.
With respect to all equipment for use in the sanitary field,
* Komline manufactures and sells between two and three ~
pereent and is a relatively insignificant factor. In both
tlie sanitary and industrial fields, defendant Kimco has
manufactured and sold about 60 percent of the rotary vac-
uum belt filters now in use where those filters employ cloth
belts suitable: for use as part of the apparatus of the
Peterson patent. |

51. In or around April 1964, Komline became aware

of the fact that-in the industrial field (as distinguished —
_ from the municipal sewerage treatment field), Komline’s
Flexibelt filter might not compete successfully with Eimco’s
cloth belt filter equipped with Eimco’s Edgetrack align-
ing device. At about the same time Komline’s patent
counsel informed Komline of the existence of the Peterson
_patent and ‘‘in the,spring of 1964, probably in March’’
1964 T. R. Komline had one or more conversations with
Mr. C. Lynn Peterson relative to the acquisition by Kom-
line-Sanderson of rights to or under the: Peterson patent
in suit. Thereafter, on August 27, 1964, Komline’s pat-.
ent counsel rendered to Komline a report entitled ‘‘Peter-
son Patent Evaluation’? and, pursuant to this report,

A41
Findings of Fact and Conclusions of Law

Mr. Komline again spoke ‘to Mr. Peterson with reference
to the Peterson patent. These talks culminated in the
April 28, 1965, letter agreement. Pursuant to this agree-
ment Komline would have ecquired title to the Peterson.
patent subject to an exclusive license to Peterson in the |
Industrial field. Thereafter the agreement was renego-
_tiated and resulted in the license agreement dated July
12, 1965. This agreement provided (1) that Komline was
to have an exclusive license in. the municipal sewerage
treatment field, (2) that Komline would have no right to
use the Peterson device in fields and industries other than
the field of municipal sewerage treatment, and (3) that
Komline could bring suit, at Komline’s expense, against
infringers in the municipal sewerage treatment field, and
for a period of one year from the date of the agreement,
against infringers whose activities extend into fields other
than the municipal sewerage field, i.e., into the Industrial
field, as aforesaid. The activities of Eimco were a sub-
ject of discussion at the negotiation meetings between the
two companies’ representatives and that the provision
extending to Komline the right within one year from the
date of the agreement to institute a suit ‘or suits for in-
fringements of the Peterson patent against a third party
whose activities extend into other than the municipal
sewerage treatment field was inserted at Komline’s request
and for payment by Komline to Peterson of a considera-
tion in an amount.of $5,000 in excess of the consideration
theretofore agreed upon. Komline did not have nor did
it acquire monopoly power in the manufacture and sale ./
- of rotary vacuum cloth belt filters, which is the field in
which the Peterson apparatus has found use.

- A42
Findings of Fact and Conclusions of Law .

52. Neither of plaintiffs utilized the provision of para-
graph V of the Peterson-Komline License Agreement
quoted hereinbefore. There is no showing that the agree-
ment had any influence or effect ‘on competition’ and the
evidence demonstrates particularly that it had no influ-
enee on the defendant. Petersen joined Komline as a
party plaintiff im this action. Eimco manufactures and
sells the accused apparatus for use in the sanitary as well
as the industrial- field. The one-year term of the right
expired on July 12, 1966.

53. The defendant has failed to prove by a preponder-
‘ance of the evidence that the plaintiffs’ patent has been
misused or that on equitable or legal grounds plaintiffs
should be barred from asserting the patent as against
‘the defendant. — as

~-

Damages

54. The Peterson patent in suit issued on February
19, 1963. Defendant became aware of the patent shortly ~
after it issued and defendant’s counsel received a copy
of the Peterson patent sometime in March, 1963. The
first accused Edgetrack apparatus sold -by defendant was
sold on July 25, 1963 to American Cyanamid Company,
Michigan City, Indiana, and installed on a later date. At
the time of sale, defendant had been in possession of a
copy of the Peterson patent for at least four months.

55. Defendant’s first sale of an accused apparatus and
subsequent sales were made with full knowledge of the
Peterson patent but under the contention that the patent

A43
Findings of Fact and Conclusions of Law

was invalid or was of such limited application as not to
be infringed by defendant’s devices.

From the foregoing Findings of Fact, the court now
draws the following: j

ConcLusions or Law

1. The-court has jurisdiction over the parties and the
subject matter of this civil action under 28 United States
Code §1338, and venue is properly laid in the District of:
Utah under 28 United States Code §1400(b).

| 2. The Peterson patent is presumed to be valid-and
defendant has the burden of establishing its asserted in-
validity by clear and convincing evidenge.

3. Defendant has not sustained its burden of proof
and the Peterson-patent is adjudged valid.

4. The accused Edgetrack apparatus: manufactured and

sold by defendant infringes the Peterson patent regard- .

less of the location of the opposed pairs of guide rollers
of the apparatus :in the path of travel in the filter belt.
All such locations are equivalent because the -two pairs
of guide rollers so located perform substantially the same
function in substantially the same way and achieve sub-
stantially the same result.

5. There is no file wrapper estoppel which precludes

applying thesdoctrine of equivalence to the claims of the |

Peterson patent and particularly the term ‘‘adjacent the

wee done

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A44
Findings of Fact and Conclusions of Law

ends of the return roller’’ because this phrase was inserted
to meet a rejection that the claims were indefinite and
somewhat misdescriptive, not a ecesiaaes as unpatentable
over the prior art.

6. Defendant infringes the Peterson patent by -manu-
facturing: and selling rotary vacuum belt filters employ-
ing two pairs of guide rollers, one located on either side
of the filter belt, designed and easily adjustable for simul-
taneous contact with belt beads on both sides of the filter
medium. :

7. The License Agreement between plaintiffs, together
with the position of plaintiffs and defendant in this field

and the acts of plaintiffs subsequent to execution. of the

License Agreement, do not constitute misuse of the Peter-
son patent.

8. Judgment will be entered in favor of plaintiffs and
against defendant, and defendant permanently enjoined
against | continued infringement of U. S. Patent No.

3,077,990. Damages are awarded to plaintiffs. and an

_accounfing is ordered to determine the total amount of

actual damages. Costs are awarded. to plaintiffs, such
costs to be. taxed by the: Clerk. Plaintiffs within 15 days
are directed to serve and lodge with the Court a proposed
form of decree in harmony with these conclusions to be
settled upon notice. |

Dated this 14th day of August, 1967.

/s/ A. SHERMAN CHRISTENSEN
United States District Judge

A45
Judgment of the Court of Appeals for the Tenth Circuit

This cause came on to be heard on the transcript of
the record from the United States District Court for the
Distr ict of Utah and was argued by counsel.

On consideration whereof, it is ordered and adjudged -

by this court that the judgment of the’said district court
in this cause be and the same is hereby affirmed.

Wiuiam L. Wurrraxer, Clerk

. By Gladys E. Hobbs
Deputy Clerk.

PES CCEA SION WR Bite Sess:

>

A46

Judgment of the District Court

The above-entitled action having come on to be heard
before the court upon open trial, and witnesses having been
heard, evidence having been presented, briefs having been
filed in behalf of the respective parties and the cause hav--
ing been fully tried before the court, and the court having
entered Findings of Fact and Conclusions of Law filed in
the United States District Court for the District of Utah,

' Central Division, on August 14, 1967, it is now

ORDERED, ADJUDGED AND DecreeD as follows:

1. Plaintiff, Peterson Filters and Engineering Com-
pany, is the owner of United States Letters Patent No.
3,077,990, issued to it on February 19, 1963, in the name.

of John G. Peterson and entitled ‘‘Filter Medium Guide.”’

2. Plaintiff, Komline-Sanderson Engineering Corpora-
tion, is now and since July 12, 1965 has been exclusive li-
censee under United.States Letters Patent No. 3,077,990
in the sanitary field, also defined as the municipal sewer-
age treatment field. |

_ 8. Defendant, The Eimco Corporation, has infringed
claims 1 and 2 of said United States Letters Patent No.
3,077,990 by its manufacture and sale of rotary drum
vacuum belt filters employing tracking and tensioning ap-

- paratus comprising two pairs of guide rollers, one pair

located on either side of and in the path of travel of the
filter belt, where said pairs of guide rollers were each
designed and easily adjustable for resilient, simultaneous
contact with beads on both sides of the belt.

4. Defendant, The Kimco Corporation, and its officers,
agents, servants, employees and attorneys, and all persons

A47_
Judgment of the District Court

‘in active concert or participation with it who receive ac-
tual notice of. this Judgment and Deerce, are, during the
remaining term of United States Letters Patent: No.
3,077,990, hereby permanently enjoined and restrained —
from making, using or selling, within the United States,
its territories or possessions, rotary drum vacuum belt
filters employing tracking and tensioning apparatus com-
prising two pairs of guide rollers, one pair located on
cither side of and in the path of travel of the filter belt,

where said pairs of guide rollers are cach designed and ..

easily adjustable for resilient, simultancous contact with
beads on both sides of the belt, or otherwise infringing
claims 1 and 2 of said United States Letters Patent No.
3,07, 990.

5. Plaintiffs are entitled to recover damages together
with interest thereon as may be fixed by the court pur-
suant to USC Title 35, Section 284, and an accounting is
ordered to determine the total amount of actual damages.

6. Plaintiffs are awarded singe in this action, such

costs to be taxed by the Clerk of the Court.

A. SHERMAN CHRISTENSEN
United States District Judge

Dated: Salt Lake City, Utah
Oct. 3, 1967

Approved as to form:

_ Walter D. Ames
Of Counsel for Plaintiffs

Mark N. Donohue
Of Counsel for Defendant

Feb. 19, 1963

Filed March 7, 1960

A48

Plaintiffs’ Ex. 1, R. 65S

-

J. G. PETERSON 3,077,990

FILTER MEDIUM GUIDE

2 Sheets-Sheet 1

INVENTOR.
John G. Peterson

: : Qe- 3 “a y

: D7 Sim %y Larerd

ATTORNEYS

g/t PETRY ER BENNY at ome
. . .

at

E
|
Feb. 19, 1963 J. G. PETERSON 3,077,990 ,
. FILTER MEDIUM GUIDE :
Filed March 7, 1960 : 2 Sheets—Sheet 2

INVENTOR. —
83 John G. Peterson
Q : BY
F-ig.-7 B77 Bre Elvrerke E:
é ATTORNEYS

oe

United States Patent Office

ADD

Patented Feb. 19, 1963

‘ - 3,077,990
FILTER MEDIUM GUIDE
John G. Peterson, Salt Lake City, Utah, assignor to
Peterson Filters and Engineering.Company, Salt Lake

of Utah
Filed Mar. 7, 1960, Ser. No. 13,129
: 2 Claims. (CL. 210—401)

This invention relates to improvements in continuous
filtering apparatus, and more particularly to improve-
ments in rotary drum apparatus, especially drum filters
having a cake discharge and filter medium cleaning sec-
tion removed from the surface of the drum.

Rotary drum filters using a filter medium formed in
an endless band or strip having a length substantially in
excess of the circumferen of the drum for passing
through a cake discharge section spaced from the drum
is well known. ‘With such filtering apparatus, however,

substantial difficulty has been experienced in maintaining™

the endless filter medium strip centered on the drum and
as it passes through the discharge section. Since.’ vacuum
filter has a drum having a perforatedssurface which must
be covered by the filter medium to maintain suction in
the drum for drawing filtrate through the-filter medium,
the filter medium must be correctly tracked so as to cover
‘the drum surface during filtering opeyations. In such de-
vices, the filter medium on leaving the drum is looped
around and through a series of rollers for discharge of
carried cake and eventually back onto the drum surface.

. As the filter medium returns to the drum surface, how-

ever, there is a definite tendency for the endless strip to
run off the drum.

It is therefore an important object of the invention to
provide a novel filter mediug: and mechanism for main-
taining an endless filter medium centered on a rotary drum
and through a discharge scction spaced from the drum
surface. The invention provides centering of the me-
dium, eliminates wrinkling of the material of the filtering
medium either on the drum or in the discharge section,
and provides positive tracking for the medium onto the
drum without training rods. - The mechanism of the in-
vention laterally’ stretches the filter medium, retarding
blinding of its Openings and provides for more complete
cleaning of the filter medium prior to its return to the
filter drum for additional filtering action.

These and other objects and advantages of the invention

may be readily ascertained by referring to the fgllow-

ing description and appended drawings in which:

FIG. 1 is a partial schematic view of a drum filter
‘with a spaced apart cake discharger for an endless filter
medium;

FIG. 2 is a detailed section of part of one embodiment
of the invention, illustrating a filter medium tensioning
and holding mechanism according to the invention;

FIG. 3 is a schematic view of a modificd spring-loaded
filter medium holding mechanism, for tracking and center-

_ ing a filter medium on a drum and providing lateral ten-
‘ sion on the medium;

FIG. 4 is a‘partial detailed view of a modified spring-
loaded mechanism for tracking and centering a filter
medium;

FIG. 5 is a schematic illustration of a gravity weighted
filter medium centering and tensioning mechanism ac-
cording to the invention;

FIG. 6 is a partial detailed view of another. spring
loaded filter medium céntering and tensioning. mecha-
nism; and

FIG. 7 is a schematic view Of a filter medium clean-
ing spray mechanism according to the invention.

in general, the cake discharger of the present invention
is applicable to a rotary vacuum drum filter, rotary pres-
sure drum filters, and other similar mechanisms utilizing

-

é.
$

20

+ spray system 11.

2

an endless filter medium or cake’supporting material of
a length substantially greater than the circumference of
the drum and a cake discharge mechanism spaced from
te drum ‘surface, as for example, rotary drum filters
shown in Wilson, U.S: Patent No. 2,812,065 and Sieben-
thal, U.S. Patent No. 2,812,064. In the particular type

of filter mechanism, a vacuum drum filter Having a per- _

forate\ cylindrical surface is partially immersed in a fluid
to be filtered which is contained in a tank. The endless
filter medium covers the mesh surface of the drum dur-
ing its immersion in the fluid (slurry) and a part of the
drum surface above the slurry to provide washing and/or
air drying of the cake on the medium. The filter medium
is then directed away from the surface of the drum
through a series of loops wherein the cake is discharged,
the medium is washed and then returned to the drum
for subsequent filtering operation.

In the schematic illustration of FIG. 1, a drum 1 ( par-
tially shown) is mounted for rotation in a tank 2 for
operation as a drum filter according to conventional prac-
tices. The Wilson and Siebenthal patents (referred to
above) illustrate one mounting construction and means
for operating such a drum filter. An endless filter me-
dium 3 is looped around the drum 1 so that it covers the
drum through a major part of an arc of revolution. The
medium is withdrawn fro mthe drum at an upper poim
and it is returned to the drum at a point such as A im-

_mediately prior to its contact with a body of slurry 5.

The filter medium completely covers the drum deck dur-
ing the filtering portion of each cycle. In the cake dis-
charge and cake washing section, the filter medium 3 passes
over a discharge roller 7 where the filter cake is re-
moved from the medium, either by the. reverse bending
of the medium or a sluicing fluid, which may be air or
water, blown through the medium to remove the cake.
The medium is then looped over a roller 8 leading an
elongated, free loop 9 over a roller 10 and then past a
The filter medium passes through a
tracking, centering and tensioning mechanism shown gen-
erally by numeral 12 and returged to the filter drum.
The centering and tensioning mechanism is explained in
detail in detail below. The elongated loop 9 is normally
filled with water, forming is called a water loop, shown
and explained in detail in the Wilson and Siebenthal pat-
ents. The water loop maintains longitudigal tension on

the filter medium by virtue of the weight of the water in |

» the loop. The water in the loop may be either contained

50

55

in an elongated tube or a free pool so that it washes the
filter medium.

The filter medium which may be used with the dévice
of the invention is an elongated strip of.such material as
woven nylon, felt, metallic cloth, scfeening, nylon taf-
feta of appropriate mesh, and similar types of filter me-
dium known in the industry. The strip of filter me-
dium is slightly wider than the width of the drum and is
substantially longer than the circumference of the filter
drum. Its ends are secured together forming an endless
filtey medium. The ends of the medium may be releas-
ably secured together by means of a hookless fastcner,
slide fasterier, lacing, or the like, as i¢ known in the art.
Both edges of the strip are folded back over an elongated
core and fastened to the body or-web of the strip leav-
ing an enlarged edge, bead, or hem completely along each
edge. A portion of such an edge is illustrated in FIG. 2
wherein the edge 15 of the material is turned back on
itself around 4 cord 16. The edge of the material may
be sewn to the body, or otherwise fastened to form a
pocket around the cord 16. In place of the cord 16 a
cable, which may be made of metal, fiber, plastic, rubber,

or an endless helical spring may be used as the core for.

the hemmed edge. It is to be understood that both edges

3,077,990

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OF NR OT TARE TTR TDR

CRE OOM

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_ solid shaft $@ which in turp is mounted on plate 51.

VOT

8,077,000

3

of the strip are so treated so as \o provide the thickened
edges on both sides of the medium.

In the embodiment illustrated in) FIG. 2, the return
idler “R,” that is, the roller adjaceit the vacuum drum
from which the filter medium returns to the drum from
the cake discharge section, is mounted yn a shaft 20 which

js journaled in a pillow block or bearings 21 for rotation. -

A disc 22 is mounted on the shaft 20, and the disc”is
pressed internally of the tubular roller R, retained in place
by a weldment 23.

The filter medium 3 is maintained centered and laterally.

stretched by means of rollers 25 and 26 which are closely
juxtaposed with the thickened edges 15 therebetween.
Thus. the core 16 bears against the outer surfaces of the
rollers. Upper roller 25-is mounted on a shaft 28 which
is mounted in an upright end plate 29 and held by @
- nut 30. A spacer 31- holds the roller in position, and
a shaft stop 32 maintains the roller on the shaft 28. The
end plate 29 is mounted on a hollow shaft 35, through
which shaft 20 is journaled and is retained in position
thereon by means of a nut 36. Roller 26 is, also, mount-
ed and ‘rotates on the hollow shaft 35 being retained in
position by stop 39. A spacer 38 maintains positioning
of the roller. A connecting rod 4@ is threadedly attached
to the plate 29 and is operatively engaged with an ad-
justing Wheel 41 mounted in a stand 42 attached to the
filter structure. The adjusting wheel is threadedly en-
gaged with the connecting shaft 4@ and provides means

for adjustment of lateral tension on the filter medium~

as may bé desired. The rollers 25 and 26 are preferably
made of nylog, polytetrafluoroethylene plastic, rubber or
equivalent material which is essentially non-abrasive
toward the filter medium with no sharp corners.

The end plate 28 being mounted on a shaft requires
some means for holding it. One such means is shown
in FIG. 2, wherein a pin 33 guides in a stationary yoke
34. The pin 33 prevents rotation of the end plate, but
is reciprocable in the yoke for tension adjustment of the
filter medium. :

Adjustment by the hand wheel moves the rollers lat-
erally in relation to the drum (not shown in FIG. 2)
and provides centering and/or tracking means for the
filter medium as well as providing lateral tensioning on
the medium immediately prior to its return to the drum.
Thus stretch changes and variations in the medium during
operation are readily compensated, as well as filter me-

dium creep on the drum.

- In the modification illustrated schematically in FIG. 3,
a yoke 45 having upper and lower rollers 25 and 26
are mounted in a manner similar to that of FIG. 2 but,
instead of the connecting rod 4®, a helical spring 47 is
interconnected with each yoke 45. Thus each side of
the filter medium runs between the rollers with the core
16 held between the rollers so as to maintain the medium
under essentially uniform tension, and it is automatically
centered or tracked on the drum 1. For simplification of
the illustration, the return roller R and means for mount-
ing the yoke are not shown in FIG. 3, but shown in de-
tail in FIG. 4.

The spring-loaded yoke mechanism is illustrated in
detail in FIG. 4, wherein the roller 2§ is mounted on a
A
spacer $2 maintains the roller 25 in position and eng stop
on shaft so holds it on the shaft. Roller 26 is mounted
mounted on a hollow shaft 53 which is secured to the
plate $1 and maintained in position by spacer 54. The
shaft $3 is reciprocably mounted on the return roller shaft
20. The helical spring 47 is secured to an eye SS on
the plate $1 and to an eye 56 on the frame providing con-
tinuous and essentially uniform tension on the filter me-
dium under the influence of the springs 47.

A pin 57 riding in arms of a stationary yoke 58 pre-
vents rotation of the plate $1, in a manner similar to the
device of FIG. 2. The yoke provides reciprocal move-

4
ment of the plate $1 along shaft 20, but prevents rotation
thereof. ;

In the modification illustrated in FIG. 5, weights
operating over pulleys replace the helical spring on the
device of FIGS. 3 and 4, also providing Continuous ten-
sioning on the filter medium 3. In this case the rollers
25 and 26, mounted similarly to the roller mount of
FIG. 4, are mounted on a back plate $1 which in turn
is reciprocably mounted over return rolier shaft 20. A
cable or line 60 mounted over a pulley 61 is secured to

the eye 55 at one end and to a weight 62 at the other

end. These opposed weights on the ends of the cable ©

60 provide lateral tension and tracking for the filter
medium 3. The weights, of course, may, be varied to
provide proper tensioning under various conditions of
operation. : ae

In the modification illustrated in FIG. 6, a return
roller 65 is made substantially wider than the filter drum
I, and is mounted on a shaft 66 journaled for rotation
in a pillow block or bearing set 67. The return roller
65 is mounted in a position adjacent the drum, similar
to the return roller R, FMS. 1, and a single filter medium
tensioning and restraining roller 68 is mounted’ adjacent
each end of the return roller 65, in position to bear
against and retain the filter medium edge 16 therebe-
tween. Correct positioning maintains the edge core 16
on the outer side of the roller 68. The roller 68 is
mounted on a shaft 69, which is shouldered at 7@ to re-
tain the roller 68 in position, and-the large portion 71
of the shaft is reciprocably mounted in a stationary
mount 72 which is secured to the frame. An eye 73
is secured on the end of the shaft 72, and a spring 75
is attached thereto to provide tension on the filter

. medium 3. The spring 75 is anchored in an eye 76

an

ct)

secured to the filter frame.

In the modification of FIG. 6 the return roller 65
coacts with the tensioning roller for providing tension-
ing on the filter medium. This provides a simplified
construction for the centering and tensioning mechanism
for the filter medium 3.

Cleaning sprays may be provided for the filter medium
edge immediately prior to its entrance into the ceatering
end tensioning rollers, and in one form a hollow yoke
8@ is provided with upper and lower spray heads 81 and
82 mounted in position to spray the filter medium 3
passing therebetween. The hollow yoke is secured to a
fluid source 83 by conventional means. The spray heads
may be replaced with wiper blades where desired.

It is obvious that where desired the fiter medium
holding rollers or wheels may be journaled with bear-
ing sets on their respective shafts. Further, the rollers
or wheels may be made replaceable for varying condi-
tions of service or operation. :

In operation it has been found that the core or cord
in the hem of each edge creeps in respect to the filter
medium, probably due to the difference of effective diam-
eter around the drum and rollers which increases the
distance of travel in relation to the body of the filter
medium itself. It is, therefore, preferable to have each
hem or turned back edge loosely on the cord, and to
have the core or cord continuous around each edge with
minimum bulging af the core or cord joint. When a
cord is used for the core, a smooth splice without knots
or bulges permits the cord to flow through the hem, in
relation to the filter medium, during operation. Thus
with any core, whether cord, cable, helical spring, etc.,
the finished splice is preferably smooth and small so that
the core freely moves through the hem without catching
and bunching the filter medium. ; :

While the invention has been described by reference to
specific embodiments, there is no intent to limit the spirit
or scope of the invention to the, precise details so set
forth.

I claim: .

1. In a filter medium tracking and tensioning device
for a rotary drum filter having a separate cake discharge

°°

le Te eh ke ee a Ts
. -

SORT ey

i‘

“ay 3,077,990

section, an endless filter medium looped over the filter
drum and extending through the cake discharge section,
which filter medium includes a bead on each edge of the
filter medium extending completely therearound, and a
filter medium return roller mounted adjacent the filter
drum, the improvement which comprises means for track-
ing the filter medium back to said drum inclusive of a
pair of rollers mounted adjacent each end of the return
roller, each pair of rollers being mounted in substantial
contacting relation and mounted with the filter medium
therebetween and in position to bear against the bead at
the edge thereof, each said pairs of rollers being arranged
to move laterally in respect to the path of travel of the
filter medium, resilient means attached to said rollers
in position so that the rollers bear against the bead at
each side of the filter medium to stretch the filter medium
therebetween and to center it in relation to the return
roller and the filter drum, and means for supporting each

pair of said rollers in position on said filter medium and

“biased against the adjacent bead at the edge thereof.

10

2. A device according to claim 1 in which each said
pair of bead contacting rollers is spring biased laterally
away from the filter medium so as to provide essentially
uniform tensioning on the filter medium.

“References Cited in the file of this patent
UNITED STATES PATENTS

877,631 SON Sec ckccwenatnnke Jan. 28,
954,466 BOON cawetiinnacwes Apr. 12, 1910
2,330,923 MIME ciwencecsenneas Oct. 5, 1943
2,880,875 PE: Sessceakenwinees Apr. 7, 1959
2,909,273 Smith ---..----------- Oct. 20, 1959
FOREIGN PATENTS
812,197 GEM BIG: cncccncans Apr. 22, 1959

1908 _-

ped eh ace abe Mien LST iy doe dase le —e lle = (RTT ¥ ° smcblngs WX a

Defendan: s Ex. C, R. 780
[Reduced in size for
insertion in this ;
Appendix }

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Source: Frix Law Library, https://www.frixlaw.com/law-library/documents/brief%3Amicro_IA40385604_0856%3A1. Public record. Not legal advice.