Ex Parte Siden et al

Patent Trial and Appeal Board

Feb 8, 2018

13036084 (P.T.A.B. Feb. 8, 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.
13/036,084 02/28/2011 Gunnar Leif Siden 19441-0477 (GE 243118) 4250
13077 7590 02/12/2018
F.versiherk SiitherlanH fTF,
EXAMINER
Suite 2300 MEADE, LORNE EDWARD
999 Peachtree Street
Atlanta, GA 30309 ART UNIT PAPER NUMBER
3741
NOTIFICATION DATE DELIVERY MODE
02/12/2018 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):
patentdocket @ eversheds-sutherland. com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte GUNNAR LEIF SIDEN and CLINT L. INGRAM
Appeal 2016-002607
Application 13/036,084
Technology Center 3700
Before MICHELLE R. OSINSKI, NATHAN A. ENGELS, and
BRENT M. DOUGAL, Administrative Patent Judges.
ENGELS, Administrative Patent Judge.
DECISION ON APPEAL
Appellants appeal under 35 U.S.C. § 134(a) from a rejection of claims
1, 4, 11, 12, 15, 22, 28, and 31—35. We have jurisdiction under 35 U.S.C.
§ 6(b).
We reverse.
Appeal 2016-002607
Application 13/036,084
STATEMENT OF THE CASE
According to Appellants’ Specification, “[t]he present [Application
relates generally to gas turbine engines and more particularly relates to a
joint between adjacent annular can combustors to promote mixing of the
respective combustion streams downstream thereof before entry into the first
stage of the turbine.” Spec. 1101. Claim 1, reproduced below, is
illustrative of the claimed subject matter:
1. A mixing joint for adjacent can combustors of a gas turbine
engine, the mixing joint comprising:
a first can combustor with a first combustion flow and a
first wall;
a second can combustor with a second combustion flow
and a second wall, wherein the first can combustor and the
second can combustor meet at a joint between the first wall and
the second wall; and
a flow disruption surface positioned between the first wall
and the second wall and configured to promote mixing of the first
combustion flow and the second combustion flow within a flow
mixing region positioned downstream of the first wall and the
second wall, wherein the flow disruption surface comprises a
first set of spikes defined by a downstream edge of the first wall
and a second set of spikes defined by a downstream edge of the
second wall.
THE REJECTION
Claims 1, 4, 11, 12, 15, 22, 28, and 31—35 stand rejected under
35 U.S.C. § 103(a) as being unpatentable in view of Brown (US 2,702,454;
Feb. 22, 1955); Nakamura et al. (JP 2009-197650; Sept. 3, 2009); Barton et
al. (US 7,159,383 B2; Jan. 9, 2007); Shibata et al. (US 6,830,436 B2; Dec.
14, 2004), Brausch et al. (US 6,360,528 Bl; Mar. 26, 2002); and Charron et
al. (US 2010/0037617 Al; Feb. 18, 2010).
2
Appeal 2016-002607
Application 13/036,084
ANALYSIS
Appellants argue the cited combination of references fails to teach or
suggest can combustors of a gas turbine engine having a mixing joint with a
“flow disruption surface” as claimed in independent claim 1. See Appeal Br,
5—6. In relevant part, claim 1 recites a “flow disruption surface . . .
comprising] a first set of spikes defined by a downstream edge of the first
wall and a second set of spikes defined by a downstream edge of the second
wall.”
The Examiner finds Brown discloses a joint 50 between can
combustors having ends that are cut back in an upstream direction thereby
“increasing the mixing distance of the flow mixing region.” Final Act. 6.
The Examiner explains that by increasing the mixing distance, the curved,
cut-back shapes of the ends of Brown’s adjacent can combustors promote
mixing and therefore constitute flow disruption surfaces. Ans. 5. Further,
the Examiner concludes it would have been obvious to modify Brown’s joint
in view of secondary references that teach using spiked edges to affect
airflow at a turbine engine’s exhaust, explaining:
improving a particular device (adjacent can combustors having
a mixing joint) based upon the teachings of such improvement
in Barton, Brausch, Shibata, and Charron, would have been
obvious to one of ordinary skill in the art, i.e., applying these
known “improvement” techniques in the same manner to the
adjacent can combustors having a flow disruption surface of
Brown, [as evidenced by] Nakamura, and the results would
have been predictable and readily recognized.
Final Act. 8.
3
Appeal 2016-002607
Application 13/036,084
Appellants argue that “[although some ‘natural’ mixing may occur
due to the increased axial distance between the joint 50 and the first stage
turbine nozzle 20 [in Brown], the joint 50 itself does not promote mixing of
the respective combustion flows because it is still a blunt joint that induces a
wake flow.” Appeal Br. 12 (emphasis omitted). According to Appellants,
Brown’s “blunt joint 50 does not have a shape or include any feature that
promotes mixing of the combustion gas flows.” Appeal Br. 12.
Consistent with Appellants’ argument, Appellants’ Specification
recognizes that prior art combustor joints have some natural mixing between
the joints and the turbine, but the Specification states that “[pjractically
speaking, the axial distance between the exit of the can combustors and the
leading edge of a first stage nozzle [of the turbine] is relatively small such
that little mixing actually may take place before entry into the turbine.”
Spec. 1103. Further, the Specification describes the need for an improved
combustor joint “without increasing the axial distance between the
combustor and the turbine” (Spec. 1105), and Appellants’ Specification
describes the claimed solution to that problem as a “flow disruption surface”
that uses its shape or geometry (e.g., the claimed “sets of spikes”) on the
downstream edge of the joint itself to enhance mixing (see Spec. ^fl[ 123
(describing sets of chevron-like spikes formed by the walls of adjacent can
combustors), 126 (“various geometries of the flow disruption surfaces 155 of
the mixing joint 150 enhance the mixing of the combustion flows . . .
without increasing the axial distance”)).
Reading the claimed “flow disruption surface . . . comprising] a first
set of spikes defined by a downstream edge of the first and a second set of
spikes defined by a downstream edge of the second wall” in light of
4
Appeal 2016-002607
Application 13/036,084
Appellants’ Specification, we conclude that the broadest reasonable
interpretation of the claimed “flow disruption surface” does not include a
conventionally shaped joint edge that relies on axial distance, instead of the
edge’s shape, to improve mixing. As depicted in the Examiner’s annotated
version of Brown’s Figure 2, reproduced below, Brown teaches increasing
the size of the “flow mixing region” (indicated with shading) by moving
combustor joint 50 from the dashed line labeled “prior art adjoining ends of
adjacent combustor walls” in an upstream direction resulting in an
“increased mixing distance.” Final Act. 3 (capitalization omitted). Brown
does not, however, describe the shape of the downstream edges of its
combustor joints, nor does Brown teach or suggest changing the shape of the
downstream edge to affect mixing.
Lonqituctina; Axis
Brown - 2,782.454 increasedMixing
j®, ' distance
Brown Fig. 2 with Examiner Annotations (Final Act. 3)
Figure 2 of Brown is a longitudinal section view of a portion of a
flame tube of a combustor and a turbine nozzle.
5
Appeal 2016-002607
Application 13/036,084
Considering the Examiner’s rejection of claim 1 in light of
Appellants’ arguments and the evidence of record, we agree with Appellants
that the Examiner has not established that it would have been obvious to a
person of ordinary skill to modify the shape of the downstream edge of
Brown’s joint. Brown and Nakamura recognize the existence of wake
downstream from the joint between can combustors, but we find no teaching
or suggestion in the cited art that the joint’s surface itself may be used to
improve mixing. Accordingly, because we disagree with the Examiner’s
finding that Brown teaches a flow disruption surface, we determine that the
Examiner’s reasoning as to why one of ordinary skill in the art would have
considered an alternative flow disruption surface to be an improvement
applicable to Brown’s joint (Final Act. 7—8) lacks rational underpinnings.
Accordingly, we are persuaded of error in the Examiner’s rejection of claims
1,4, 11, 12, 15,22,28, and 31-35.
DECISION
We reverse the Examiner’s rejection of claims 1,4, 11, 12, 15, 22, 28,
and 31—35.
REVERSED
6