Ex Parte Sishtla

Patent Trial and Appeal Board

Jan 25, 2018

12933729 (P.T.A.B. Jan. 25, 2018)

United States Patent and Trademark Office
UNITED STATES DEPARTMENT OF COMMERCE
United States Patent and Trademark Office
Address: COMMISSIONER FOR PATENTS
P.O.Box 1450
Alexandria, Virginia 22313-1450
www.uspto.gov
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO.
12/933,729 09/21/2010 Vishnu M. Sishtla PA-057.10955-US-AA 1208
87059 7590 01/29/2018
Cantor Colburn LLP - Carrier
20 Church Street, 22nd Floor
Hartford, CT 06103
EXAMINER
TANENBAUM, TZVI SAMUEL
ART UNIT PAPER NUMBER
3744
NOTIFICATION DATE DELIVERY MODE
01/29/2018 ELECTRONIC
Please find below and/or attached an Office communication concerning this application or proceeding.
The time period for reply, if any, is set in the attached communication.
Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the
following e-mail address(es):
usptopatentmail@cantorcolbum.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte VISHNU M. SISHTLA
Appeal 2017-003845
Application 12/933,7291
Technology Center 3700
Before: STEFAN STAICOVICI, JILL D. HILL, and
ARTHUR M. PESLAK, Administrative Patent Judges.
STAICOVICI, Administrative Patent Judge.
DECISION ON APPEAL
STATEMENT OF THE CASE
Vishnu M. Sishtla (Appellant) appeals under 35 U.S.C. § 134(a) from
the Examiner’s decision in the Final Action (dated Dec. 10, 2015,
hereinafter “Final Act.”) rejecting claims 1, 4, and 5 under 35 U.S.C.
§ 103(a) as unpatentable over Miller, Jr. (US 6,443,711 Bl, iss. Sept. 3,
2002, hereinafter “Miller”), Bush et al. (US 6,826,926 B2, iss. Dec. 7, 2004,
1 According to Appellant’s Appeal Brief (filed July 7, 2016, hereinafter
“Br.”), the real party in interest is Carrier Corporation. Br. 2.
Appeal 2017-003845
Application 12/933,729
hereainafter “Bush”), and Schulze (US 2,967,410, iss. Jan. 10, 1961).2,3 We
have jurisdiction under 35 U.S.C. § 6(b).
SUMMARY OF DECISION
We AFFIRM.
CLAIMED SUBJECT MATTER
Appellant’s invention relates to “noise suppression in screw
compressors used in commercial and industrial air conditioning and
refrigeration systems.” Spec. 1,11. 5—7.
Sole independent claim 1 is representative and reads as follows:
1. A screw compressor for use in a chiller assembly, the
compressor comprising:
a plurality of cooperating screw rotors disposed at a
compressor housing configured to increase the pressure of a
vaporized refrigerant flowing through the compressor;
a motor to drive rotation of at least one screw rotor of the
plurality of screw rotors disposed fluidly upstream of the
plurality of screw rotors;
a bearing housing disposed fluidly downstream of the
screw rotors, and including screw bearings configured to
facilitate rotation of the screw rotors;
a first venturi tube arranged in a first flow path of the
refrigerant in the bearing housing fluidly downstream of the
screw rotors configured to cause a pressure drop in the
refrigerant; and
2 Upon entering Appellant’s Amendment After-Final Action, filed March 9,
2016, the Examiner’s rejection of claims 1, 4, and 5 under 35 U.S.C. § 112,
second paragraph, as being indefinite, has been rendered moot, and, hence,
is not part of the instant appeal. See Adv. Act. 17 (dated Apr. 15, 2016); see
also Final Act. 2.
3 Claims 2, 3, and 6—20 are withdrawn. Br. 2.
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Application 12/933,729
a first inlet port at a throat of the first venturi tube and
configured to deliver liquid refrigerant from a condenser of the
chiller assembly to the flow path of the refrigerant in the
compressor and configured to reduce pulsations in the pressure
of the refrigerant discharged from the compressor, the pressure
drop in the refrigerant at the first venturi tube resulting in
delivery of the liquid refrigerant through the first inlet port.
ANALYSIS
Appellant has not presented arguments for the patentability of claims
4 and 5 apart from claim 1. See Br. 5. Therefore, in accordance with 37
C.F.R. § 41.37(c)(l)(iv), we select claim 1 as the representative claim to
decide the appeal of the rejection of these claims, with claims 4 and 5
standing or falling with claim 1.
The Examiner finds that Miller discloses screw compressor 10
including inter alia, screw rotors 20-22 for increasing the pressure of a
vaporized refrigerant that flows through the compressor, motor 40 for
driving at least one of the screw rotors, and bearing housing 12 having screw
bearings 36—38. Final Act. 4 (citing to Miller, Fig. 1). The Examiner further
finds that Miller fails to disclose that “screw compressor 10 is for use in a
chiller assembly.'1'’ Id. Nonetheless, the Examiner finds that Bush discloses
the use of screw compressor 12 in a chiller assembly. Id. (citing Bush, col.
2,1. 65). Accordingly, the Examiner concludes that it would have been
obvious to a person of ordinary skill in the art to modify Miller to use a
chiller, as taught by Bush, in order “to remove heat from a liquid (e.g. water)
which can then be circulated through a heat exchanger to cool air or
equipment as required and thereby cool air or equipment without piping
refrigerant over distances.” Id. at 4—5 (citing Bush, col. 2,11. 64—66).
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The Examiner further notes that Miller’s screw compressor, as
modified by Bush, does not disclose a venturi tube and an inlet port at a
throat of the venturi tube as further required by independent claim 1. Id. at
5. Nonetheless, the Examiner then finds that Schulze discloses (1) venturi
tube 26a located in the first flow path of a refrigerant that causes a pressure
drop in the refrigerant and (2) inlet port 40 at throat 29a of venturi tube 26a
that delivers liquid refrigerant to the compressor. Id. (citing Schulze, Figs.
1, 2). The Examiner, thus, concludes that because “Bush teaches that, in
general, injecting liquid refrigerant into a compression cycle at a compressor
reduces pulsations,” a person of ordinary skill in the art would have
modified Miller to include Schulze’s venturi tube and inlet port arrangement,
“to reduc[e] pressure pulsations and associated radial noise produced during
a compression cycle through the injection of liquid refrigerant into the
compression cycle,” as taught by Bush, “while automatically modulating the
liquid refrigerant flow from the condenser according to the quantity of
refrigerant flowing through the first flow path from a compressor unit,” as
taught by Schulze. Id. at 6—7 (citing Bush, Abstract, col. 1,11. 5—11 and 55—
60, col. 3,11. 25—33 and 45—55; Schulze, col. 2,11. 14—19).
Appellant argues that, in contrast to independent claim 1, which
requires delivering liquid refrigerant in the compressor at a bearing housing
downstream of the rotors, in Bush’s system, liquid refrigerant is delivered
either at a location outside the compressor, namely, at discharge port 24 or
suction port 23, or at a point “along the compression cycle.” Br. 4.
Appellant explains that Bush’s disclosure of “along the compression cycle”
means that “compression is still occurring, and thus the injection is not
downstream of the rotors but at some point along the rotors and not at a
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Application 12/933,729
bearing housing downstream of the rotors.” Id. Appellant further asserts
that Schulze’s element 9, cited by the Examiner as a bearing housing, is
described in Schulze as a “main frame,” and as “[n]o bearings are indicated
in the main frame 9,” Schulze provides “no indication that it is in fact a
bearing housing.” Id. Thus, according to Appellant, the combined teachings
of Miller, Bush, and Schulze fail to disclose or suggest “‘a first venturi tube
arranged in a first flowpath of the refrigerant in the bearing housing fluidly
downstream of the screw rotors’ as required by claim 1.” Id. (underlining
omitted).
The Examiner responds that Schulze’s frame 9 constitutes a “bearing
housing” as broadly claimed because “frame 9 impliedly houses a bearing
for the rotation of. . . shaft 12 of motor 11.” Examiner’s Answer 2 (dated
Oct. 24, 2016, hereinafter “Ans.”). Moreover, even though Schulze’s frame
9 may not constitute a “bearing housing,” nonetheless, according to the
Examiner, because Schulze’s venturi tube is “immediately downstream of a
compressor housing [8] . . . one of ordinary skill in the art would understand
to locate the venturi tube of Schulze within the bearing housing 12 of Miller
as the bearing housing 12 is located immediately downstream of compressor
housing 13.” Id. at 2—3.
We are not persuaded by Appellant’s arguments because such
arguments are not commensurate with the Examiner’s rejection. The
Examiner did not rely on the injection location in Bush’s system as being
downstream of the rotors. See Final Act. 5. Rather, the Examiner relies on
Schulze as teaching a venturi tube located “‘immediately downstream’ of a
compressor housing where refrigerant is compressed.” Ans. 2. Specifically,
Schulze discloses that refrigerant gas is “discharged by the compressor
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Application 12/933,729
through a suitable discharge passage leading directly into the hermetic
casing. The discharge passage includes the discharge port 14 of the
compressor unit which directs the high pressure discharge gas into an
aspirating means [venturi 26a].” Schulze, col. 3,11. 8—15 and 47; see also
Final Act. 7. The Examiner then modifies Miller’s system to place a venturi
tube, as taught by Schulze, immediately downstream of Miller’s compressor
housing 13. See Ans. 2—3. Miller discloses that “[bjearings 36, 37 and 38
are received in and supported by outlet casing 12 [bearing housing] which
defines flow paths (not illustrated) between the discharge of coacting pairs
of rotors and the compressor discharge chamber 11-2 formed in discharge
cover 11.” Miller, col. 3,11. 27—31, Fig. 1; see also Final Act. 4. Appellant
does not adequately explain why a person of ordinary skill in the art would
not discern from Schultze’s teaching of placing a venturi tube “immediately
downstream” of a compressor discharge to place a venturi tube in Miller’s
bearing housing. See Ans. 3. Appellant has not persuasively shown error in
the Examiner’s findings or reasoning in combining the teachings of Schulze
and Miller.
Appellant further argues that because Bush uses a booster pump for
increasing the pressure of the liquid refrigerant flow, which is
“fundamentally different from the operation of Appellant’s claim 1 and of
the Schulze reference” because a low pressure zone is created in the
compressor via a venture tube, a person of “ordinary skill[] in the art would
not combine the teachings of Bush with those of Schulze.” Br. 4—5 (citing
Bush, col. 3,1. 38).
We do not agree with Appellant’s contention because it is not
commensurate with the Examiner’s rejection. The Examiner acknowledges
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Application 12/933,729
that Bush discloses using “a booster pump, or other device” to provide a
“sufficiently high source of liquid refrigerant,” but correctly notes that Bush
also discloses that liquid refrigerant can be introduced at any “point in the
compression process where the pressure is reasonably . . . below that in
condenser outlet 28.” Ans. 3^4 (citing Bush, col. 3,11. 18—25 and 34^40).
We agree with the Examiner that Bush broadly relates to reducing noise by
injecting liquid refrigerant into a compression cycle and is not limited to
doing so by using a booster pump. See Ans. 3.
Furthermore, given that Schulze’s venturi tube creates a region of low
pressure in the throat zone so that liquid refrigerant [from the condenser] can
enter the throat zone (see Schulze, col. 3,11. 36—39; see also Final Act. 5),
Appellant does not adequately explain why Bush’s teachings of introducing
liquid refrigerant from the condenser to a low pressure point are
fundamentally different from those of Schulze. As Appellant provides no
persuasive evidence or technical explanation as to why the combined
teachings of the references as proposed by the Examiner do not meet the
claims, we are not apprised of Examiner error.
In conclusion, for the foregoing reasons, we sustain the rejection of
independent claim 1 under 35 U.S.C. § 103(a) as unpatentable over Miller,
Bush, and Schulze. Claims 4 and 5 fall with claim 1.
SUMMARY
The Examiner’s decision rejecting claims 1, 4, and 5 under 35 U.S.C.
§ 103(a) as unpatentable over Miller, Bush, and Schulze is affirmed.
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No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a). See 37 C.F.R.
§ 1.136(a)(l)(iv).
AFFIRMED
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