Ex Parte Wilson et al

Board of Patent Appeals and Interferences

Sep 14, 2010

11062970 (B.P.A.I. Sep. 14, 2010)

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.
11/062,970 02/22/2005 Jody W. Wilson 2004P15632US 1498
7590 09/15/2010
Siemens Corporation
Intellectual Property Department
170 Wood Avenue South
Iselin, NJ 08830
EXAMINER
SUNG, GERALD LUTHER
ART UNIT PAPER NUMBER
3741
MAIL DATE DELIVERY MODE
09/15/2010 PAPER
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.
PTOL-90A (Rev. 04/07)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________________

Ex parte SIEMENS POWER GENERATION, INC.
____________________

Appeal 2009-007541
Application 11/062,970
Technology Center 3700
____________________

Before JAMESON LEE, RICHARD TORCZON, and
SALLY C. MEDLEY, Administrative Patent Judges.

LEE, Administrative Patent Judge.

DECISION ON APPEAL1

1 The two-month time period for filing an appeal or commencing a civil
action, as recited in 37 C.F.R. § 1.304, or for filing a request for rehearing,
as recited in 37 C.F.R. § 41.52, begins to run from the “MAIL DATE”
(paper delivery mode) or the “NOTIFICATION DATE” (electronic delivery
mode) shown on the PTOL-90A cover letter attached to this decision.

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A. STATEMENT OF THE CASE
This is a decision on appeal by the real party in interest, Siemens
Power Generation, Inc. (“SPG”) under 35 U.S.C. § 134(a) from a final
rejection of claims 1-20. We have jurisdiction under 35 U.S.C. § 6(b).
We affirm-in-part.
References Relied on by the Examiner
Adelizzi et al. (“Adelizzi”) 3,750,398 Aug. 7, 1973
Cromer et al. (“Cromer”) US 6,412,268 B1 Jul. 2, 2002
Sekihara et al. (“Sekihara”) US 6,546,627 B1 Apr. 15, 2003

The Rejections on Appeal
The Examiner rejected claims 1-12 under 35 U.S.C. § 103(a) as
unpatentable over Cromer and Sekihara.
The Examiner rejected claims 13-20 under 35 U.S.C. § 103(a) as
unpatentable over Adelizzi, Cromer, and Sekihara.

The Invention
The invention relates to a transition duct connecting a combustor and
a turbine in a gas turbine engine. (Spec. 1:4-6.)
Claim 1 is reproduced below (App. Br. 10 Claims App’x.):
1. A transition duct for a gas turbine engine for conducting hot
combustion gas along a direction of flow between a combustor outlet
and a turbine inlet, the transition duct comprising:

a plurality of panels, each panel formed to define a corner
region extending longitudinally in a direction generally parallel to the
direction of flow;

a plurality of subsurface cooling channels formed through the
corner region of each panel, the cooling channels being part of a
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closed cooling scheme and extending longitudinally in a direction
parallel to the direction of flow and effective to cool the entire
respective corner region; and

a weld joining edges of adjacent panels remote from the corner
region.
B. ISSUES
1. Has SPG persuaded us that the Examiner incorrectly
determined that the teachings of Cromer and Sekihara account for the claim
feature of cooling channels that extend longitudinally in a transition duct and
are effective to cool the entire corner regions of the duct?
2. Has SPG persuaded us that the Examiner erred in determining
that the teachings of Cromer and Sekihara account for the claim feature of a
weld that joins the edges of adjacent panels of a duct and is remote from the
corner regions of the duct?
3. Has SPG persuaded us that the Examiner incorrectly
determined that a person of ordinary skill in the art would have recognized
that values of the thickness of transition duct panels and the radius of
curvature of the corners of the duct that appear in claims 3-8, 11, 12, and 17-
20 would have been obtained by optimization through routine
experimentation?
4. Has the Examiner adequately accounted for the specific spacing
between transition ducts that is set forth in claims 14-16 to establish a prima
facie basis for rejecting claims 14-16 over the prior art?
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C. PRINCIPLES OF LAW
During examination, claim terms are given their broadest reasonable
interpretation consistent with the specification. In re Zletz, 893 F.2d 319,
321 (Fed. Cir. 1989).
The broadest reasonable interpretation rule recognizes that before a
patent is granted the claims can be readily amended as a part of the
examination process and that an applicant has the opportunity and
responsibility to remove any ambiguity through the amendment process. In
re Bigio, 381 F.3d 1320, 1324 (Fed. Cir. 2004).
The initial burden is on the examiner to establish a prima facie basis
to reject the claims. In re Oetiker, 977 F.2d 1443, 1445 (Fed. Cir. 1992).
D. FACTS and ANALYSIS
The Examiner rejected claims 1-12 over Cromer and Sekihara and
claims 13-20 over Adelizzi, Cromer, and Sekihara.
Claims 1-12
Claims 1 and 10 are independent claims. The patentability of
dependent claims 2 and 9 is not argued apart from claims 1 and 10. SPG
separately argues claims 3-8, 11, and 12. We focus on the disputed
limitations.
Claims 1, 2, 9, and 10
Claims 1 and 10 each require a transition duct having a plurality of
panels each of which defines a corner region that extends longitudinally in a
direction of a flow of combustion gas. The claims further require that the
panels contain a plurality of subsurface cooling channels that operate to cool
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corner regions of the panels. Specifically, claim 1 recites that the cooling
channels are “extending longitudinally in a direction parallel to the direction
of flow and effective to cool the entire respective corner region.” Claim 10
recites that the cooling channels are “extending subsurface along the corners
parallel to the direction of flow of the combustion gas and effective to cool
the entire respective corner[.]”
The Examiner found that Cromer discloses a transition duct including
cooling channels that are configured as set forth in the above-quoted
limitation. (Ans. 5:6-10.)
Cromer discloses a transition duct end frame assembly that includes a
transition duct end frame 26 secured to a transition duct 28. (Cromer 3:9-
12.) End frame 26 contains a series of cooling holes 42 arranged around the
entire perimeter of the end frame. (Id. at 3:43-47.)
Cromer’s Figure 3 illustrates a front view of transition duct end frame
26 and is reproduced below:

Figure 3 illustrates Cromer’s transition end frame.
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Thus, Cromer discloses that its cooling holes 42, which extend around
the entire periphery of the frame, are also present in the frame’s corner
regions.
Cromer’s Figure 2 is reproduced below and depicts a partial cross-
section of transition duct 28 and its end frame 26 and illustrates the
extension of holes 42 within the duct end frame.

Figure 2 shows a partial cross-section of Cromer’s transition duct and
transition duct end frame.

As shown in the figure above, the transition duct end frame 26 is
welded to transition duct 28 at weld 29 and forms an end portion of the duct.
(Cromer 3:9-12.) Cooling air enters the transition duct end frame through
holes 36 and passes through cooling holes 42 into annulus 44 formed within
cooling sleeve 30. (Id. at 3:16-35.) Cooling sleeve 30 and its annulus 44
surrounds the transition duct and operates to cool the remainder of the duct.
(Id. at 2:29-41.) The Examiner found that the longitudinal extension of
cooling holes 42 within the corners of transition duct end frame 26 meets the
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feature of the claims directed to cooling channels “extending longitudinally”
through the corner regions of panels that make up the transition duct. The
Examiner also found that the cooling air which passes through cooling holes
42 and enter impingement cooling sleeve 30 is “effective to cool the entire
respective corner region” of the duct. (Ans. 10:5-13.)
SPG argues that its claims 1 and 10 are similar in scope and each
requires that the cooling channels must extend the entire length of the
corners of the panels that make up the transition duct. (App. Br. 5:8-9.)
According to SPG, Cromer does not disclose cooling channels that extend
through the entire length of the corners of its transition duct. (Id. at 5:9-13.)
SPG also takes the view that Cromer discloses cooling structures only within
outlet end regions of its duct and not within panels that make up the duct.
(Id. at 5:20-22.)
SPG’s arguments are unpersuasive. The Examiner determined that
the transition duct end frame forms panels that are part of the transition duct.
That determination is reasonable. As shown in Cromer’s Figure 2, transition
duct end frame 26 is integrally welded to transition duct 28 such that the end
frame is continuous and co-extensive with the duct. SPG does not
meaningfully explain why a transition duct end frame that is continuous and
co-extensive with the duct is not itself reasonably regarded as part of the
transition duct.
Moreover, SPG’s characterization of the transition duct end frame as
not being a portion of the duct is inconsistent with Cromer’s disclosure. In
describing its invention, Cromer states that “one end of said transition duct
including an end frame” (Cromer 4:9-10) and the “forward end of said
transition duct includes a transition duct end frame.” (Cromer 4:40-41.)
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Thus, Cromer discloses that the transition duct “includes” the transition duct
end frame. That is, the transition duct end frame is disclosed as a part of the
transition duct. We reject SPG’s argument.
Furthermore, during examination, claim terms are given their broadest
reasonable interpretation consistent with the specification. In re Zletz, 893
F.2d at 321. Contrary to SPG’s assertion, its claims do not require that the
cooling channels extend the entire “longitudinal length of the duct as far as
the corners extend.” (App. Br. 5:8-9.) The broadest reasonable
interpretation rule recognizes that before a patent is granted the claims can
be readily amended as a part of the examination process and that an
applicant has the opportunity and responsibility to remove any ambiguity
through the amendment process. In re Bigio, 381 F.3d at 1324. If SPG had
intended that the cooling channels extend along the entire length of the
panels, it could have amended the claims accordingly.
Here, claim 1 as written simply requires that the cooling channels
extend longitudinally through “a corner region” of the duct and are
“effective to cool the entire respective corner region.” (App. Br. 10 Claims
App’x.) Similarly, claim 10 requires that the cooling channels extend along
“corners” of a duct and are “effective to cool the entire respective corner.”
(Id. at 12.) A “corner” or “corner region” of the duct need not extend the
entire length of the duct. It is not inconsistent with SPG’s specification that
cooling channels may extend along a corner or a corner region that is only a
portion of the length of the duct and be effective to cool the entire corner or
corner region in which the channels extend.
As shown in Cromer’s, Figure 2, cooling holes 42 are subsurface
channels that extend longitudinally in the corners or corner regions of the
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end frame of the transition duct and operate to cool those corners or corner
regions. The cooling holes are thus “effective” to cool the entire corner or
corner region in which the holes extend. In any event, the cooling holes also
deliver cooling air to impingement sleeve 30 which entirely surrounds the
transition duct. It is evident that the rest of the duct in the longitudinal
direction is cooled by airflow through the holes as well.
SPG also argues that the feature of its claims 1 and 10 directed to
welding panels of the transition duct to one another in areas that are
“remote” from the corners is missing from the prior art. (App. Br. 5:25-6:5.)
The Examiner relied on Sekihara to account for that requirement, pointing in
particular to Figure 8C of that reference. (Ans. 3:12-20.) SPG contends that
Sekihara is “silent regarding any such panel welds” and is thus inadequate to
teach the required welding. (App. Br. 5:30.)
SPG’s argument is unpersuasive. Sekihara is not silent with respect to
welding panels of a transition duct. Sekihara discloses a transition duct and
describes a method for repairing frame portions of the duct by removing and
replacing sections of the frame. In particular, Sekihara discloses that
portions are removed and replaced with sections 22 that are welded to the
remaining sections of the frame.

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Figure 8(c) illustrates the welding locations disclosed in Sekihara and
is reproduced below:

Figure 8(c) depicts a sectional view of Sekihara’s frame.

As illustrated in the figure above, the areas of the frame where the
replaced sections 22 are welded to the frame (shown using straight line
segments) are not located in any of the corners of the frame. Rather, those
sections are welded to the frame at areas other than the corners. The
Examiner reasoned that in light of the teachings of Sekihara, a person of
ordinary skill in the art would have recognized that portions that form part of
a transition duct may be welded to one another in areas remote from the
corners. The Examiner concluded that Sekihara’s teachings taken with
Cromer satisfy SPG’s claims 1 and 10. The Examiner’s reasoning and
conclusion are reasonable and are not addressed by SPG. We are not
persuaded of any error in the Examiner’s rejection.
For the foregoing reasons, we sustain the rejection of claims 1 and 10
over Cromer and Sekihara. Claims 2 and 9 are argued collectively with
claims 1 and 10. We also sustain the rejection of claims 2 and 9 over
Cromer and Sekihara.

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Claims 3-8, 11, and 12
Claims 3-8, 11, and 12 are ultimately dependent on one of claims 1
and 10 and add features directed to specific ranges of the radius of curvature
of the corner regions of the transition duct and specific thicknesses of the
panels that make-up the duct. As explained in SPG’s specification (e.g.,
Spec. 4:3-8) and as set forth in the claims, e.g., claims 3 and 11, the
specified radius of curvature and thickness values are selected as being
effective to reduce forming strains in the panels to desired low levels so that
the integrity of the cooling channels in the duct corners is maintained.
In accounting for the values appearing in SPG’s claims 3-8, 11, and
12, the Examiner takes the position that those values are result-effective
variables that may be optimized. In particular, the Examiner states (Ans.
12:11-15):
[T]he radius of curvature of the corner regions and the thickness of
the panels of the duct are result-effective variables that one of
ordinary skill in the art would have found obvious to optimize through
routine experimentation so that the panels are not subjected to
unacceptable loads during operation (i.e. the stress and strain of the
panels remain in acceptable regimes.)

SPG’s claims require subsurface cooling channels in the corners of its
duct. The claims do not require that the channels extend the entire length of
the duct. However, in the embodiment of SPG’s invention which
incorporates the claimed values for the above-noted parameters those values
are chosen for a purpose that is pertinent to channels that do extend the
entire length of the panels. It is to maintain strain on the duct at a desired
level that prevents deformation of subsurface cooling channels extending the
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entire length of the corners of the duct panels when the panels are bent into
their final shape.
The prior art does not disclose cooling channels extending along the
entire length of the transition ducts. Thus, there is no reasonable basis to
conclude that the Examiner’s proposed optimizing of the prior art would
lead to the claimed range of values for the corner radii of curvature and for
the panel thickness. The configuration of the prior art structure to be
optimized is different from that of SPG’s disclosed embodiment. Because
the starting structures are different, the optimal values for the corner
curvature and panel thickness may well be different.
For the foregoing reasons, we do not sustain the Examiner’s rejection
of claims 3-8, 11, and 12 as unpatentable over the teachings of Cromer and
Sekihara.
Claims 13-20
The Examiner rejected claims 13-20 over Adelizzi, Cromer and
Sekihara. SPG argues the claims based on features appearing in independent
claim 13. SPG also separately argues dependent claims 14-20.
Claim 13
Claim 13 is directed to a gas turbine engine that includes a plurality of
spaced transition ducts. The transition ducts each include subsurface cooling
channels spaced along corner bend regions of the transition duct to
“effectively cool” each transition duct. (App. Br. 13 Claims App’x.) Thus,
the structure and configuration of the cooling channels of claim 13 are
similar to those set forth in claims 1 and 10. SPG’s arguments with respect
to claim 13 are effectively the same as those made in connection with claims
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1 and 10. Namely, SPG contends that Cromer and Sekihara do not teach a
transition duct having cooling channels that extend in a longitudinal
direction through the corner regions of the duct. SPG also contends that
Adelizzi does not make up for the alleged deficiencies of Cromer and
Sekihara.
For essentially the same reasons given with respect to claims 1 and 10
above, we reject SPG’s argument that the prior art, in particular, Cromer,
lacks disclosure of a transition duct having cooling channels that extend
longitudinally in corner regions of the duct and are effective to cool the
length of the duct. We sustain the rejection of claim 13 over Adelizzi,
Cromer, and Sekihara.
Claims 14-20
Claims 14-20 are each dependent on claim 13. According to both
SPG and the Examiner, claims 14-20 require specific dimensions for the
radius of curvature of the corner regions of the duct and specific thicknesses
for the duct panels. (App. Br. 8:8-9; Ans. 8:1-2.)
With respect to claims 17-20, SPG and the Examiner are correct in
their respective assessments of the requirements of the claims. Each of those
claims requires particular values for either the radius of curvature of the duct
panels or the thickness of the ducts, or both. As he did in connection with
claims 3-8, 11, and 12, the Examiner contends that the values set forth in the
claims would be obtainable by optimizing the teachings of the prior art.
(Ans. 8:2-12.)
For the same reasons given above in association with claims 3-8, 11,
and 12, we are not persuaded that claims 17-20 are rendered obvious by the
prior art. In particular, the record does not adequately support that one with
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ordinary skill in the art would have realized that the values of the radius of
curvature and panel thickness presented in claims 17-20 are optimum values
for prior art ducts with cooling channels that do not extend the entire length
of the duct’s corners. Accordingly, we do not sustain the rejection of claims
17-20 over Adelizzi, Cromer and Sekihara.
With regard to claims 14-16, those claims do not require any
particular panel thickness or corner radius of curvature. Rather, the claims
specify particular sizes for the gaps that exist between adjacent transition
ducts of the plurality of ducts introduced in claim 13. The Examiner
generally contends that it would have been obvious to optimize the prior art
to obtain “Appellant’s claimed ranges” (Ans. 8:11-13) but does not refer to
any gaps between transition ducts in his rejection, much less that any
particular values for the gaps may be derived from the prior art.
The initial burden is on the examiner to establish a prima facie basis
to reject the claims. In re Oetiker, 977 F.2d at 1445. We conclude that
because the Examiner does not advance any analysis in connection with the
teachings of the prior art concerning the selection of particular gap spacing
between transition ducts, the Examiner has not sufficiently established a
prima facie basis to reject claims 14-16.
We do not sustain the rejection of claims 14-16 over Adelizzi, Cromer
and Sekihara.
E. CONCLUSION
1. SPG has not persuaded us that the Examiner incorrectly
determined that the teachings of Cromer and Sekihara account for the claim
feature of cooling channels that extend longitudinally in a transition duct and
are effective to cool the entire corner regions of the duct.
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2. SPG has not persuaded us that the Examiner incorrectly
determined that the teachings of Cromer and Sekihara account for the claim
feature of a weld that joins the edges of adjacent panels of a duct and is
remote from the corner regions of the duct.
3. SPG has persuaded us that the Examiner incorrectly determined
that a person of ordinary skill in the art would have recognized that values of
the thickness of transition duct panels and the radius of curvature of the
corners of the duct that appear in claims 3-8, 11, 12, and 17-20 would have
been obtained by optimization through routine experimentation.
4. The Examiner has not adequately accounted for the specific
spacing between transition ducts that is set forth in claims 14-16 to establish
a prima facie basis for rejecting claims 14-16 over the prior art.
F. ORDER
The rejection of claims 1, 2, 9, and 10 under 35 U.S.C. § 103(a) as
unpatentable over Cromer and Sekihara is affirmed.
The rejection of claims 3-8, 11, and 12 under 35 U.S.C. § 103(a) as
unpatentable over Cromer and Sekihara is reversed.
The rejection of claim 13 under 35 U.S.C. § 103(a) as unpatentable
over Adelizzi, Cromer, and Sekihara is affirmed.
The rejection of claims 14-20 under 35 U.S.C. § 103(a) as
unpatentable over Adelizzi, Cromer, and Sekihara is reversed.

TIME PERIOD
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)(1) (2009).
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AFFIRMED-IN-PART

Siemens Corporation
Intellectual Property Department
170 Wood Avenue South
Iselin NJ 08830