UNITED TECHNOLOGIES CORPORATION

Patent Trials and Appeals Board

Jun 22, 2020

2019006057 (P.T.A.B. Jun. 22, 2020)

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.
14/908,225 01/28/2016 Kevin J. Ryan 67097-2562PUS1;72694US02 8118
54549 7590 06/22/2020
CARLSON, GASKEY & OLDS/PRATT & WHITNEY
400 West Maple Road
Suite 350
Birmingham, MI 48009
EXAMINER
BEEBE, JOSHUA R
ART UNIT PAPER NUMBER
3745
NOTIFICATION DATE DELIVERY MODE
06/22/2020 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):
ptodocket@cgolaw.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte KEVIN J. RYAN, KARL A. MENTZ, and
MARK J. ROGERS
Appeal 2019-006057
Application 14/908,225
Technology Center 3700
Before JENNIFER D. BAHR, WILLIAM A. CAPP, and
LISA M. GUIJT, Administrative Patent Judges.
BAHR, Administrative Patent Judge.
DECISION ON APPEAL
STATEMENT OF THE CASE
Pursuant to 35 U.S.C. § 134(a), Appellant1 appeals from the
Examiner’s decision to reject claims 1–23. We have jurisdiction under
35 U.S.C. § 6(b).
We AFFIRM.

1 We use the word Appellant to refer to “applicant” as defined in 37 C.F.R.
§ 1.42(a). Appellant identifies the real party in interest as United
Technologies Corporation. Appeal Br. 1.
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Application 14/908,225

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CLAIMED SUBJECT MATTER
Appellant’s invention is directed to “a gas turbine engine, and more
particularly to a wedge seal for use[] between non-rotating structures of a
gas turbine engine.” Spec. ¶ 2. Claim 1, reproduced below, is illustrative of
the claimed subject matter.
1. A seal assembly arrangement for a gas turbine engine
comprising:
first and second non-rotating structures respectively
providing first and second faces;
a sealing assembly includes discrete first and second
sealing rings respectively engaging the first and second faces,
the first and second sealing rings slideably engaging one
another at a sliding wedge interface.
REFERENCES
The prior art relied upon by the Examiner is:
Name Reference Date
Glynn US 5,292,138 Mar. 8, 1994
Nakaoka US 2006/0038355 A1 Feb. 23, 2006
Lutjen US 2013/0113168 A1 May 9, 2013
Sha US 2014/0035240 A1 Feb. 6, 2014

REJECTIONS
Claims 1, 7, 10–13, 15, 16, 21, and 22 stand rejected under
35 U.S.C. § 103 as unpatentable over Sha and Glynn.
Claims 2–6 and 17–20 stand rejected under 35 U.S.C. § 103 as
unpatentable over Sha, Glynn, and Lutjen.
Claims 8, 9, 14, and 23 stand rejected under 35 U.S.C. § 103 as
unpatentable over Sha, Glynn, and Nakaoka.
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OPINION
Obviousness—Sha and Glynn
Appellants argue claims 1, 7, 10–13, 15, 16, 21, and 22 together.
Appeal Br. 2–4. We decide the appeal of this rejection on the basis of
claim 1, with the remaining claims standing or falling with claim 1.
See 37 C.F.R. § 41.37(c)(1)(iv) (permitting the Board to select a single claim
to decide the appeal as to a single ground of rejection of a group of claims
argued together).
The Examiner finds that Sha discloses a seal assembly arrangement
substantially as recited in claim 1, including, in pertinent part, first and
second sealing rings respectively providing first and second faces that
slideably engage one another at a sliding wedge interface. Final Act. 3–4
(citing Sha, Figs. 2, 7, 8, 14; ¶¶ 28, 29). However, the Examiner finds that
Sha “does not teach: [w]herein the rings are discrete.” Id. at 4.
Notably, it is not apparent to us, and the Examiner does not cogently
explain, why the first and second seal sections of Sha’s “annular split ring”
seal, for use at joints between casings, such as a joint between a casing of a
combustion can and the annular plate of a combustion wrapper, are not
“discrete” first and second sealing rings as called for in claim 1. See Sha
¶¶ 23, 27–30. Although Sha refers to the annular seal as “an annular split
ring having inclined surfaces between the split sections of the seal” (Sha
¶ 28 (emphasis added)), the split seal sections are separate and discrete rings.
See id. ¶ 33 (disclosing alignment devices, such as corresponding tongues
and grooves, arranged at one or more locations along the circumference of
the seal to ensure that the first section remains aligned and in contact with
the second section). If the split seal sections were part of a unitary, one-
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piece seal structure, rather than discrete sealing rings, there would be no
need for alignment devices arranged along the circumference to ensure
alignment of the sections. Likewise, the disclosure of such alignment
devices at one or more locations along the circumference of the seal conveys
that the first and second seal sections are coextensive along the
circumference of the ring. Further, Sha’s disclosure in paragraphs 27, 41
and 42 regarding how the sliding seal operates, using pressure differences
across the split seal to cause one section of the seal to slide over the other
section until it abuts against the walls of the slots to form a seal, suggests
that both seal sections extend along substantially the entire circumference of
the annular ring to form an effective annular seal along the substantially the
entire circumference thereof, thereby each forming a ring.
Nevertheless, the Examiner relies on Glynn for its teaching of using a
split ring assembly comprising two separate and distinct rings to permit
improved sealing, which provides the ability to seal over a wider range of
pressures, lower leakage rates, and the ability to adjust the parameters of the
seal more easily by merely altering the angle of the seals. Final Act. 4
(citing Glynn, Fig. 2, 3:1–54, 4:5–34). The Examiner determines it would
have been obvious to modify Sha by using two separate rings angled
opposite each other, as taught by Glynn, “for the purpose of improving the
sealing rate, widening the sealing pressure values it is usable under, and
making the seal more easily adjustable to varying sealing needs, by applying
the two rings with the angular sealing ranges along it as taught.” Id.
Appellant argues that Glynn’s split ring assembly is intended to
overcome problems associated with rotating seals and, thus, would not be
applicable to Sha’s seal, which is between non-rotating structures. Appeal
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Br. 3. This argument is not persuasive because, although the friction and
centrifugal forces generated when using a split ring between rotating
structures presents additional complicating factors, both Sha and Glynn use
differential pressure to bias the split seal sections into sealing position. See
Sha ¶¶ 27, 32; Glynn 1:16–18, 4:5–8. Thus, the advantages that Glynn cites
for using a split ring assembly comprising two separate and distinct rings
would also be applicable to Sha.2
Appellant also argues that the “proposed modification would change
the principle of operation [of Sha] and render [Sha] unsatisfactory for its
intended purpose because,” according to Appellant, “both embodiments of
Glynn’s split ring assembly 41 require centrifugal force to move to sealing
engagement” and “[t]he non-rotating structures of Sha would not provide
this centrifugal or ‘rotating inertial force.’” Appeal Br. 3–4. This argument
is unpersuasive. As discussed above, both Sha and Glynn use differential
pressure to bias the split seal sections into sealing position. See Sha ¶¶ 27,
32; Glynn 1:16–18, 4:5–8. Although Glynn addresses additional friction
forces and centrifugal forces that result from the rotation of the rotating
structures, neither Sha nor Glynn suggests that differential pressure alone,
without the centrifugal forces that would result from rotation, would be
insufficient to bias the sections of the annular seal relative to one another to
form a gas tight seal. In fact, Sha discloses that the pressure difference
across the split seal caused by any gas leaks into the joint above a threshold
level pushes one seal section relative to the other section along the inclined
abutting surfaces to form a gas tight seal. See Sha ¶¶ 27, 41.

2 Indeed, as discussed above, Sha appears to use a split ring seal comprising
two separate and distinct sections for similar reasons. See Sha ¶ 27.
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In responding to the Examiner’s citation of Koleilat
(US 2005/0242519 A1) and Synott (US 2004/0219014 A1) in the Advisory
Action as evidence that forces other than rotation may bias a split wedge to
drive wedge action, Appellant submits that Koleilat and Synott disclose a
biasing spring and a resilient energizer to apply a resilient biasing force,
respectively, to maintain the seal, and argues that “the Examiner has not
identified any part of Sha or Glynn that suggests such an additional biasing
spring might be used with those sealing arrangements.” Appeal Br. 4. This
argument is incorrect. Gas pressure activates Sha’s seal by biasing one
section against the other section, such that an additional biasing spring is not
required for proper operation of Sha’s seal, as evidenced by the
embodiments of Sha’s Figures 7 and 8, for example. See, e.g., Sha ¶ 27
(disclosing a sliding seal that is “biased by gas pressure to form a gas tight
seal in a joint between a casing or casing segments”). However, Sha’s
Figure 14 embodiment, which is one of the embodiments that the Examiner
cites (Final Act. 3), includes deformable seal 138, such as a flexible rod,
rope, or cord. Sha ¶ 48. Sha discloses that “[t]he deformable seals enhance
the sealing between the seal and the walls of the chambers and thereby assist
in preventing leakage of pressurized gas from the turbine casing.” Id.
For the above reasons, Appellant does not apprise us of error in the
rejection of claim 1 as unpatentable over Sha and Glynn. Accordingly, we
sustain the rejection of claim 1, and of claims 7, 10–13, 15, 16, 21, and 22,
which fall with claim 1, as unpatentable over Sha and Glynn.
Obviousness—Sha, Glynn, and Lutjen
Appellant argues claims 2 and 17 together, and relies on the
arguments for claims 2 and 17 in contesting the rejection of claims 3–6 and
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18–20. Appeal Br. 4–5. We decide the appeal of this rejection on the basis
of claim 2, with claims 3–6 and 17–20 standing or falling with claim 2. See
37 C.F.R. § 41.37(c)(1)(iv).
The Examiner finds that Sha does not teach that the seal assembly
separates a first pressurized area from a second pressurized area. Final
Act. 7; see Appeal Br. 4 (citing paragraphs 36–37 of Sha discussing a static
gas pressure on the front 77 of the seal and atmospheric pressure on the back
78 of the seal, once the seal sections shift to enhance sealing). The
Examiner finds that Lutjen teaches that “[i]t is necessary to provide effective
sealing between BOAS [(blade outer air seal)] structures.” Final Act. 7
(citing Lutjen, Fig. 2). The Examiner further takes official notice that “it is
extremely well-known in the art[] that BOAS structures [are] located
opposite turbine blades, and that the downstream element following such
BOAS would also be a turbine blade outer platform surface.” Final Act. 7–8
(citing Zelesky (US 2015/0345319) and Synott (US 2004/0219014) as
examples). Further, the Examiner notes that Synnott discusses the
shortcomings of non-dynamic or non-biased seals, which may not create
effective seals between structures that may shift unequally during thermal
expansion. Id. at 8 (citing Synnott ¶¶ 1, 2). The Examiner also finds that
Sha recognizes this issue and discloses seals designed to address this issue
by means of their sliding interface and biasing from air pressure from high
pressure regions to low pressure regions. Id. (citing Sha ¶¶ 7, 26–27). The
Examiner determines it would have been obvious to apply the dynamic,
sliding seals (i.e., the annular split seals comprising first and second seal
sections) at locations between BOAS and adjacent vane platforms in Sha’s
engine identified by Lutjen as areas needing sealing to handle pressure
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leakage from the core flow toward a lower pressure cooling flow area, in
order to accommodate, through biasing action, for imperfect sealing due to
shifting of structures from unequal thermal expansion. Id.
Appellant argues that “Sha’s seal would be unsuitable for Lutjen’s
application” because Sha’s seal “relies on the [pressure] difference between
a sealed space and the atmosphere to bias its sections 48, 50 into a closed
sealing position.” Appeal Br. 4–5.
In response, the Examiner observes that Appellant has provided no
evidence to support the assertion that the pressure force needed to bias the
sliding seal sections into sealing position must be the pressure differential
between the pressure in a pressurized region and atmospheric pressure,
rather than the difference between the pressure in a high pressure pressurized
region and a lower pressure pressurized region. Ans. 7. The Examiner also
points out that Glynn teaches that the seal uses “the differential pressure
between cavities to assist in seal sealing” and permits adjusting the seal
parameters, such as the angle of the abutting faces of the sections and size of
the seal elements relative to the sealing space in which they move, to seal
over a wider range of pressures and achieve lower leakage rates. Ans. 4, 5,
7–8 (citing Glynn 1:16–22). Further, the Examiner emphasizes that Sha
teaches making a determination as to the threshold difference in gas pressure
acting along the front and back of the seal that will cause the first seal
section to slide over the second seal section and determining the optimal
inclined slope of the opposing surfaces in the seal based on the threshold gas
pressure differential determination. Id. at 8 (citing Sha ¶ 37).
We agree with the Examiner that Appellant’s assertion that Sha’s seal
would work only for sealing a pressurized region from atmospheric pressure
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and would be unsuitable for sealing between two pressurized regions lacks
evidentiary support in the record before us. To the contrary, Sha’s teachings
of adjusting the parameters of the seal, including the angle of the abutting
faces of the first and second seal sections, and Glynn’s teaching of using
such split ring seals with first and second sliding seal sections to seal
between pressurized cavities, provide ample evidentiary basis to establish a
reasonable expectation of success in using Sha’s/Glynn’s sliding seal
arrangement to separate one pressurized area from another, as called for in
claim 2.
For the above reasons, Appellant does not apprise us of error in the
rejection of claim 2 as unpatentable over Sha, Glynn, and Lutjen.
Accordingly, we sustain the rejection of claim 2, and of claims 3–6 and 17–
20, which fall with claim 2, as unpatentable over Sha, Glynn, and Lutjen.
Obviousness—Sha, Glynn, and Nakaoka
In contesting the rejection of claims 8, 9, 14, and 23, Appellant argues
only that “[t]he addition of the teachings of [Nakaoka] does not overcome
the deficiencies with respect to Sha and Glynn and base claim 1.” Appeal
Br. 5. For the reasons discussed above, Appellant’s arguments do not
apprise us of error in the rejection of claim 1 as unpatentable over Sha and
Glynn, and, likewise, fail to apprise us of error in the rejection of claims 8,
9, 14, and 23 as unpatentable over Sha, Glynn, and Nakaoka, which we thus
sustain.
DECISION SUMMARY
In summary:
Claims
Rejected
35 U.S.C.
§
Reference(s)/Basis Affirmed Reversed
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1, 7, 10–13,
15, 16, 21,
22
103 Sha, Glynn 1, 7, 10–13,
15, 16, 21,
22

2–6, 17–20 103 Sha, Glynn, Lutjen 2–6, 17–20
8, 9, 14, 23 103 Sha, Glynn,
Nakaoka
8, 9, 14, 23
Overall
Outcome
1–23

TIME PERIOD FOR RESPONSE
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)(iv).
AFFIRMED