Ex Parte Agrawal et al

Patent Trial and Appeal Board

Dec 11, 2017

13191979 (P.T.A.B. Dec. 11, 2017)

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.
13/191,979 07/27/2011 Giridhari L. Agrawal 4525-0034-1 5131
35301 7590 12/18/2017
MCCORMICK, PAULDING & HUBER LLP
CITY PLACE II
185 ASYLUM STREET
HARTFORD, CT 06103
EXAMINER
LETTMAN, BRYAN MATTHEW
ART UNIT PAPER NUMBER
3746
NOTIFICATION DATE DELIVERY MODE
12/18/2017 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):
patentdocket @ ip-lawyers .com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte GIRIDHARI L. AGRAWAL, CHARLES W. BUCKLEY,
and MUTHUSAMY RAJENDRAN
Appeal 2016-007484
Application 13/191,9791
Technology Center 3700
Before LINDA E. HORNER, ERIC C. JESCHKE, and
PAUL J. KORNICZKY, Administrative Patent Judges.
HORNER, Administrative Patent Judge.
DECISION ON APPEAL
STATEMENT OF THE CASE
Giridhari L. Agrawal et al. (Appellants) seek our review under
35 U.S.C. § 134(a) of the Examiner’s decision rejecting claims 1-23, 25, and
27. Final Office Action (July 30, 2015) [hereinafter “Final Act.”]. Claims
24 and 26 are canceled. Final Act. 1. We have jurisdiction under 35 U.S.C.
§ 6(b).
We REVERSE.
1 Appellants identify R & D Dynamics Corporation as the real party in
interest. Appeal Brief 3 (December 17, 2015) [hereinafter “Appeal Br.”].
Appeal 2016-007484
Application 13/191,979
CLAIMED SUBJECT MATTER
Appellants’ claimed subject matter relates to “turbomachinery, such
as blowers, compressors, generators, and alternators, and . . . methods for
cooling such turbomachinery.” Specification 2 (filed July 27, 2011)
[hereinafter “Spec.”]. Claims 1, 13, and 23 are independent. Claims 1 and
23 are illustrative of the subject matter on appeal and are reproduced below.
1. A turbomachine for processing a high-temperature
gas, comprising:
(a) a hot end having a hot end housing for processing the
gas flowing between an inlet and an outlet of the hot end housing,
including:
a hot end rotating shaft mounted within the hot end
housing for rotation about a central longitudinal axis;
a rotor device mounted on the hot end rotating shaft
for rotation therewith;
at least one hot end journal bearing assembly
radially supporting the hot end rotating shaft; and
a hot end thrust bearing assembly axially supporting
the hot end rotating shaft;
(b) a cool end having an electric component housing and
including:
a cool end rotating shaft mounted within the electric
component housing for rotation about a central
longitudinal axis;
an electric component comprising a rotor mounted
for rotation with the cool end rotating shaft and a stator
assembly mounted in stationary relationship with the
electric component housing relative to the rotor;
at least one cool end journal bearing assembly
radially supporting the cool end rotating shaft; and
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Application 13/191,979
a cool end thrust bearing assembly axially
supporting the cool end rotating shaft; and
(c) a compliant mechanical coupling connecting the hot
end rotating shaft with the cool end rotating shaft to transfer
operational torque between the respective rotating shafts and to
suppress heat transfer from the hot end to the cool end.
23. A recirculation cooling method for a turbomachine
using the process gas of the turbomachine, wherein said
turbomachine comprises a hot end taking the form of one of a
blower, a compressor and a turbine, said hot end including a hot
end rotating assembly mounted within a hot end housing to
handle the process gas between an inlet and an outlet, and a cool
end taking the form of one of a motor, a generator and an
alternator, said cool end including a cool end rotating assembly
mounted within a cool end housing that drives or is driven by the
hot end rotating assembly, said cooling method comprising:
providing a cooling circuit path for guiding the process gas
over the hot end rotating assembly and the cool end rotating
assembly;
drawing the process gas through the cooling circuit path
using a cooling fan mounted on the cool end rotating assembly
for rotation therewith; and
suppressing heat transfer from the hot end to the cool end
of the turbomachine using a thermal choke assembly disposed
between the hot end housing and the cool end housing.
Appeal Br. 28-29, 35-36 (Claims Appendix).
EVIDENCE
The Examiner’s decision relies upon the following evidence:
Nasvytis US 4,408,953 Oct. 11, 1983
Noe US 5,497,615 Mar. 12, 1996
Mruk US 6,193,473 B1 Feb. 27, 2001
Lubell US 7,112,036 B2 Sept. 26, 2006
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Application 13/191,979
REJECTIONS
The Final Office Action includes the following rejections:
1. Claims 1-6, 9, 10, 13-17, 20-23, 25, and 27 stand rejected under
35 U.S.C. § 103(a) as unpatentable over Noe, as evidenced by
Mruk.
2. Claims 7, 8, 18, and 19 stand rejected under 35 U.S.C. § 103(a) as
unpatentable over Noe, as evidenced by Mruk, and Lubell.
3. Claims 11 and 12 stand rejected under 35 U.S.C. § 103(a) as
unpatentable over Noe, as evidenced by Mruk, and Nasvytis.
ANALYSIS
First Ground of Rejection: Obviousness over Noe, as Evidenced by Mruk
Independent Claim 1
The Examiner finds that Noe’s turbomachinery includes a hot end
having a hot end housing (bearing housing 550 and combustor cowling 712)
and a cool end having an electric component housing (compressor housing
310). Final Act. 3 (citing Noe, Figs. 1A, 9). The Examiner finds that Noe’s
tie bar 610 corresponds to the claimed “compliant mechanical coupling”
connecting a hot end rotating shaft (flanged rotor 510) with a cool end
rotating shaft (alternator retaining shaft 204) to transfer operational torque
between these rotating shafts and to suppress heat transfer from the hot end
to the cool end. Id. at 4 (citing Noe, Fig. 9). The Examiner further finds that
Noe discloses a rotor device (compressor impeller 312 and turbine wheel
400) mounted on the hot end rotating shaft (flanged rotor 510) for rotation
therewith. Id. at 3.
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Application 13/191,979
Appellants contend that the Examiner’s findings are incorrect
because: (1) Noe’s compressor impeller 312 is not part of the hot end of
Noe’s machine, and (2) Noe’s tie bar 610 is not a “compliant mechanical
coupling,” does not connect a hot end rotating shaft with a cool end rotating
shaft, and does not suppress heat transfer between a hot end rotating shaft
and a cool end rotating shaft. Appeal Br. 14-15.
With regard to the first argument, Appellants contend that compressor
impeller 312 is disposed within the compressor housing 310, which the
Examiner identified as the cool end housing. Id. at 13-14. Thus, Appellants
argue compressor impeller 312 cannot be found to correspond to the claimed
“rotor device” because it is not included in the hot end. Id. at 14.
We agree with Appellants that Noe’s compressor impeller 312 is
housed within the compressor housing 310 and is on a cool end of Noe’s
machine. In particular, Noe discloses that “alternator-stator 202 rotates the
compressor impeller 312 at a rotational speed that produces compressed air
in the compressor plenum chamber 326 to a temperature of between 60 and
100 degrees Fahrenheit.” Noe 12:55-59 (emphasis omitted). Noe teaches
that the compressed air in “compressor plenum chamber 326 is used to cool
the thrust and radial complaint foil bearing housing 550 which in turn cools
the thrust and radial compliant foil bearings 620 and 630.” Id. 13:21-25
(emphasis omitted). By contrast, Noe describes that the compressed air
exiting the diffuser section 336 is “approximately 350 degrees Fahrenheit”
and that the compressed air is further heated in recuperator 110 “to a
temperature of approximately 1000 degrees Fahrenheit” before being
conducted to combustor 700. Id. 13:30-32,58-62.
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With regard to the second argument, Appellants assert that “the tie bar
610, the compressor impeller 300 [sic 312], the turbine wheel 400 and
flanged rotor 510 form part of a single rotating assembly that encompasses
both hot and cool ends of Noe’s machine.” Appeal Br. 14. “Thus, Noe
teaches that a hot component (the turbine wheel 400) should be mounted on
a same shaft (e.g., the tie bar 610) as two cool components (the compressor
impeller 300 [sic, 312] and the alternator rotor 222).” Id. at 15. “In stark
contrast, claim 1 recites discrete ‘hot end’ and ‘cool end’ rotating shafts that
are connected by a compliant mechanical coupling.” Id. at 16.
We also agree with Appellants’ second argument that Noe’s tie bar
610 does not “suppress heat transfer from the hot end to the cool end,” as
recited in independent claim 1. Noe discloses that “both compressor
impeller 312 and turbine wheel 400 are lockingly engaged to the thrust and
radial shaft 510 by tie-bar 610, locking both compressor impeller 312 and
turbine wheel 400 together in compression” and that “tie-bar 610 engages
recess 210, in friction fit engagement of retaining shaft 204.” Noe 9:23-28
(emphasis omitted); Fig. 3A. Thus, as argued by Appellants, turbine wheel
400, compressor impeller 312, and retaining shaft 204 are all connected to a
single shaft, i.e., tie bar 610, such that tie bar 610 is not a compliant
mechanical coupling connecting a hot end rotating shaft and a cool end
rotating shaft to suppress heat transfer between the two shafts.
For these reasons, we do not sustain the rejection of independent
claim 1, and its dependent claims 2-6, 9, and 10, as unpatentable over Noe,
as evidenced by Mruk.
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Independent Claim 13
Similar to independent claim 1, independent claim 13 recites “a hot
end rotating assembly mounted within the hot end housing” and “a
compliant mechanical coupling connecting the hot end rotating assembly
with the electric component end rotating assembly” that “suppresses] heat
transfer from the hot end to relatively lower temperature electric component
end.” Appeal Br. 32 (Claims Appendix). The Examiner relies on the same
deficient findings discussed above to find that Noe discloses these claim
elements. Final Act. 3—4. For the same reasons discussed above, we find
that the Examiner’s findings are not supported by a preponderance of the
evidence because: (1) Noe’s compressor impeller 312 is not part of a hot
end rotating assembly mounted within a hot end housing because
compressor impeller is mounted within a cool end housing 310, and
(2) Noe’s tie bar 610 is not a compliant mechanical coupling that suppresses
heat transfer from the hot end to relatively lower temperature electric
component end.
For these reasons, we do not sustain the rejection of independent
claim 13, and its dependent claims 14-17 and 20-22, as unpatentable over
Noe, as evidenced by Mruk.
Independent Claim 23
Independent Claim 23 is directed to “[a] recirculation cooling method
for a turbomachine.” Independent claim 23 does not recite the use of a
compliant mechanical coupling to suppress heat transfer from a hot end to a
cool end of the machine. Rather, claim 23 recites only the suppression of
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heat transfer using a thermal choke assembly disposed between the hot end
housing and the cool end housing.
The Specification describes that “the hot end H is separated from the
cool end Cby the thermal choke assembly 138 that acts as a thermal barrier
between the two sides of the machine 100.” Spec. ^ 57. Specifically, the
Specification describes hot and cold choke plates 140, 142, which are
preferably designed with thin cross-sections for minimum heat conduction
and maximum heat dissipation through natural convection. Id.
“Accordingly, the thermal barrier formed by the thermal choke assembly
138 acts as a thermal choke to protect the cool end C of the turbomachine
100 and provide a significant temperature gradient across the hot end //and
the cool end C of the turbomachine 100.” Id.
The Examiner finds that Noe discloses a thermal choke assembly in
that the portion of compressor housing 310 surrounded by air flow 162
reduces heat transfer from the hot end to the cool end. Final Act. 4 (citing
Noe, Figs. 3C, 9). Appellants argue that the Examiner erred in rejecting
claim 23 because “Noe does not even teach a ‘hot end’ housing” and “the
narrowing portion of Noe’s compressor housing 310 is not properly
characterized as a ‘thermal choke’ positioned between a hot end and a cool
end of Noe’s machine.” Appeal Br. 22-23.
We agree with Appellants that the narrowed end of Noe’s compressor
housing 310 is not a thermal choke. Noe depicts that the walls of the
tapering section 318 and the walls of diffuser section 336 of compressor
housing 310 are thicker than the walls of annular section 314. Noe, Fig. 3B.
Contrary to the thin choke plates of Appellants’ thermal choke assembly, the
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relatively thicker walls of compressor housing 310 at the end that abuts
relatively hotter thrust and radial air bearing housing 550 might actually
permit conduction of heat from the relatively hotter housing 550 to
compressor housing 310. Further, Noe does not explicitly teach that area of
the compressor housing 310 adjacent to housing 550 acts as a thermal choke.
Rather, Noe discloses that compressor inlet air 164 is drawn by rotation of
compressor impeller 312 into diffuser section 336, and diffuser section 336
channels the high pressure air flow through compressor outlet passageways
324 to form high pressure turbulent air flow 162 in compressor plenum
chamber 326. Noe 13:16-21. Noe describes that compressor impeller 312
produces compressed air of between approximately 60 and 100 degrees
Fahrenheit, and that “[t]he outlet passageways 324 of the diffuser section
336 is shaped in such a manner that the compressed air is raised to a
temperature of approximately 350 degrees Fahrenheit.” Id. 12:55-59,
13:30-32 (emphasis omitted). This air flow 162 is used to cool housing 550
and its bearings 620, 630. Id. 13:21-25. Thus, although the air flow
surrounding the exterior of compressor housing 310 may be used to cool
housing 550, there is insufficient evidence that the narrowed end of the
compressor housing 310 suppresses heat transfer from bearing housing 550
to compressor housing 310 such that it acts as a thermal choke.
For these reasons, we do not sustain the rejection of independent
claim 23, and its dependent claims 25 and 27, as unpatentable over Noe, as
evidenced by Mruk.
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Second and Third Grounds of Rejection
The remaining grounds of rejection of dependent claims 7, 8, 11, 12,
18, and 19 rely on the same deficient findings as to the disclosure of Noe as
discussed above in the first ground of rejection of independent claims 1 and
13. Thus, for the same reasons, we likewise do not sustain the rejection of
claims 7, 8, 11, 12, 18, and 19 as unpatentable over Noe, as evidenced by
Mruk, and further in view of either Lubell or Nasvytis.
DECISION
The decision of the Examiner rejecting claims 1-23, 25, and 27 is
reversed.
REVERSED
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