Ex Parte Ahmad et al

Patent Trial and Appeal Board

Aug 10, 2017

13002986 (P.T.A.B. Aug. 10, 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.
13/002,986 03/31/2011 Fathi Ahmad 2008P10281WOUS 5857
22116 7590 08/14/2017
SIEMENS CORPORATION
INTELLECTUAL PROPERTY DEPARTMENT
3501 Quadrangle Blvd Ste 230
EXAMINER
WOLCOTT, BRIAN P
Orlando, EL 32817 ART UNIT PAPER NUMBER
3745
NOTIFICATION DATE DELIVERY MODE
08/14/2017 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):
IPDadmin.us@siemens.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte FATHI AHMAD, HANS-THOMAS BOLMS, and
CHRISTIAN LERNER
Appeal 2016-0022571
Application 13/002,986
Technology Center 3700
Before LINDA E. HORNER, THOMAS F. SMEGAL, and LISA M. GUIJT,
Administrative Patent Judges.
HORNER, Administrative Patent Judge.
DECISION ON APPEAL
STATEMENT OF THE CASE
Fathi Ahmad et al. (“Appellants”) seek our review under 35 U.S.C.
§ 134(a) of the Examiner’s decision rejecting claims 11-14, 16-23, and 25-
27. Final Office Action (March 12, 2015) (hereinafter “Final Act.”). We
have jurisdiction under 35 U.S.C. § 6(b).
We AFFIRM.
1 Appellants name Siemens Aktiengesellschaft as the real party in interest.
Appeal Brief 1 (July 2, 2015) (hereinafter “Appeal Br.”).
Appeal 2016-002257
Application 13/002,986
CLAIMED SUBJECT MATTER
Appellants’ claimed subject matter relates to “a turbine blade or vane
for a gas turbine.” Spec. ^ 2. Claims 11 and 19 are independent claims.
Claim 11 is illustrative of the subject matter on appeal and is reproduced
below.
11. A turbine blade or vane for a gas turbine,
comprising:
a hollow main blade or vane part around which a hot gas
may flow;
a plurality of openings;
a plurality of interposed webs;
a cavity; and
a plurality of turbulence elements,
wherein the plurality of openings are distributed at a
trailing edge of the blade or vane, and used for blowing out a
coolant, which cools the turbine blade or vane, and are separated
from one another by the plurality of interposed webs,
wherein the cavity is connected fluidically to the plurality
of the openings and is provided in an interior of the main blade
or vane part;
wherein in the cavity the plurality of turbulence elements
are provided upstream from the plurality of interposed webs,
wherein each turbulence element extends from a first inner
surface of a suction-side wall of the main blade or vane part to a
second inner surface of a pressure-side wall of the main blade or
vane part and each turbulence element has an incident-flow side
facing toward a flow of coolant that arrives there,
wherein the plurality of turbulence elements as seen in a
longitudinal section and/or a cross section of the main blade or
vane part include a C-shaped design with an at least partially
concavely curved incident-flow side, and
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wherein two arc ends of the turbulence element which lie
at opposite ends from one another face toward the flow of coolant
that arrives there during operation to increase a pressure loss.
Appeal Br. 9 (Claims Appendix).
REJECTIONS
The Final Office Action includes the following rejections:
1. Claims 11, 12, 14, and 16-18 stand rejected under 35 U.S.C.
§ 103(a) as unpatentable over Surace (US 7,125,225 B2, issued
October 24, 2006) and Hall (US 5,246,341, issued September 21,
1993).
2. Claim 13 stands rejected under 35 U.S.C. § 103(a) as unpatentable
over Surace, Hall, and Cunha (US 2007/0237639 Al, published
October 11,2007).
3. Claims 19-23 and 25-27 stand rejected under 35 U.S.C. § 103(a)
as unpatentable over Cunha and Hall.
ANALYSIS
First Ground of Rejection of Claims 11, 12, 14, and 16-18 as Unpatentable
over Surace and Hall
Appellants argue the claims subject to the first ground of rejection as a
group. Appeal Br. 5. We select claim 11 as representative of this group, and
claims 12, 14, and 16-18 stand or fall with claim 11. 37 C.F.R.
§ 41.37(c)(l)(iv).
The Examiner finds that Surace discloses the turbine blade
substantially as recited in claim 11, except that Surace fails to teach the
turbulence elements including “a C-shaped design with an at least partially
concavely curved incident-flow side” and “wherein the two arc ends of the
turbulence element. . . face toward the flow of coolant that arrives there
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during operation to increase a pressure loss.” Final Act. 5-6. The Examiner
relies on Hall to disclose turbulence elements 46 of C-shaped design as
recited in claim 11. Id. at 6. The Examiner proposes to modify the
turbulence elements of the turbine blade of Surace by constructing them with
the shape of the turbulence elements of Hall and arranging the two arc ends
to face toward the flow of coolant as taught by Hall “for the purpose of
promoting additional heat transfer.” Id. at 7.
Appellants argue the Examiner erred in finding that Hall’s ribs are
C-shaped in the longitudinal section of the turbine blade because Hall’s ribs
are “turned down relative to the root.” Appeal Br. 5 (quoting Hall, col. 3,
1. 11). Appellants contend that the Specification defines a C-shaped element
in paragraph 37 as being a crescent shape with two pointed ends and/or arc
ends. Id. at 5-6. We disagree with Appellants’ assertion that the
Specification defines C-shaped in this manner.
Appellants’ Specification describes that “turbulence elements 42
shown in figure 3 have an at least partially concavely curved incident-flow
side 44 which faces toward the incident flow of cooling air 40” and
“turbulence elements 42 . . . therefore have a C-shaped longitudinal section,
i.e.[,] are in the form of a crescent, with the arc ends 46 of the turbulence
elements 42 being oriented in such a manner that they at least slightly face
toward the flow of coolant that arrives there during operation.” Spec. ^ 37.
Thus, the Specification refers to C-shaped turbulence elements as being
concavely curved, crescent shaped, with arc ends. We find no description in
paragraph 37 that defines C-shaped elements as having pointed ends. To the
extent Appellants assert that “crescent shaped” implies pointed ends, this
meaning of “crescent” does not comport with the use of the term in
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Appellants’ Specification to refer to turbulence elements 42 having flat arc
ends 46. Spec., Figs. 3, 4; see also id. 18 (describing the arcuate form of
the C-shaped design turbulence elements as being “like a circular segment or
else like an ellipse segment, i.e.[,] crescent-shaped.”) We find no error in
the Examiner’s determination that ribs 46 of Hall are C-shaped in that they
are concavely curved and are akin to an ellipse segment.
Further, the C-shape as seen in a longitudinal section of the blade is
defined in the Specification with reference to the direction of incident
coolant flow, i.e., with the at least partially concavely curved incident-flow
side and the arc ends facing toward the incident flow of cooling air. In Hall,
the cooling air travels up longitudinal passage 50 from root section 30 and is
incident upon ribs 46. Hall, col. 3,11. 8-13, Fig. 3. As shown in
longitudinal section in Figure 3, the concavely curved incident flow side and
arc ends of Halls’ ribs 46 face down toward the root section and, thus, face
the incident flow of cooling air. Thus, Hall’s ribs 46 are C-shaped with
respect to the incident flow as seen in a longitudinal section of the blade.
Appellants further argue that “Hall’s ribs (46) are not turbulence
elements” because the ribs do not support flow separation. Appeal Br. 6
(citing Hall, col. 3,1. 16); Reply Br. 2-3. The Examiner responds that “any
structure placed within a flow path creates turbulence, therefore, because
Hall’s ribs are in the cooling flow path, they will create turbulence.”
Ans. 15. Hall discloses that “[t]he leading edges 52 of the airfoil-shaped ribs
46 are turned down relative to the root section to capture some of the total
pressure available in longitudinal passage 50.” Hall, col. 3,11. 10-13
(emphasis added). Thus, some of the flow of cooling air traveling radially
up passage 50 from root section 30 is turned from the radial to axial
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direction by leading edge 52 of rib 46, and some air continues traveling up
passage 50. Hall’s airfoil-shaped ribs 46 are described as “eliminat[ing] the
tendency for cooling flow separating from the rib as it turns from radial to
axial direction.” Hall, col. 3,11. 15-17. Even if the portion of the flow that
is turned to the axial direction and travels along the front curve of rib 46 is
perfectly laminar, we agree with the Examiner that some turbulent flow
would occur as the radially flowing cooling air first impinges on rib 46. In
other words, turbulent flow would result at leading edge 52 of rib 46 at
which point a portion of the radial flow in passage 50 separates from the
remaining radial flow and turns in the axial direction. Thus, we find no error
in the Examiner’s determination that ribs 46 are “turbulence elements” as
recited in claim 11.
Appellants further contend that Halfs ribs 46 do not increase a
pressure loss, as claimed, and, instead, the ribs “are turned down relative to
the root section to capture some of the total pressure available in
longitudinal passage 50” and to “prevent buildup of pressure potential which
could lead to separations.” Appeal Br. 6 (quoting Hall, col. 3,11. 10-12);
Reply Br. 2-3.
Claim 11 recites that the two arc ends of the turbulence element face
toward the flow of coolant that arrives there during operation to increase a
pressure loss. Claim 11 fails to recite a frame of reference against which to
gauge an increase in pressure loss. Appellants’ Specification describes “a
further increased pressure loss - compared with the cylindrical pin fins
known from the prior art - in the flow of coolant upstream from the
openings at the trailing edge of the turbine blade or vane.” Spec. ^ 11. The
Specification further describes that “[cjompared with the pedestals 32
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arranged in rows, the turbulence elements 42 have a further increased flow
resistance, and therefore an increased pressure loss which prevents an
increase in coolant consumption is established at this point.” Id. 39. The
language of claim 11, however, is broader than the increase in pressure loss
described in the Specification, which is described only with reference to
comparison with the prior art cylindrical pin fms. Thus, claim 11 broadly
requires that the turbulence elements increase a pressure loss as compared,
for example, to a cavity with no turbulence elements. As we found supra,
Hall’s ribs 46 result in turbulent flow at the leading edges of the ribs. We
agree with the Examiner that this turbulent flow also increases a pressure
loss as compared to a cavity without such ribs. Ans. 16 (“because the ribs
also create turbulence as established above, turbulence further increases a
pressure loss at the rib”).
Further, as shown in Figure 3 of Hall, the two arc ends of ribs 46
which lie at opposite ends from one another face toward the flow of coolant
that arrives there during operation. Appellants argue that “Hall’s Figure 3
shows that a flow coming up from the root in passage 50 would be incident
on the curved front rib, not on both ends.” Reply Br. 3. Appellants’
argument that the flow of coolant fluid impinges on only one end of the rib
is not commensurate with the scope of claim 11, which does not require flow
to be incident on both ends. Rather, claim 11 recites only that the flow
arrive at the turbulence element.
Appellants further argue that the Examiner erred in rejecting claim 11
because the Examiner’s proposed modification is based on “impermissible
hindsight.” Appeal Br. 7 (Appellants contending that without knowledge of
Appellants’ invention “one skilled in the art would not take an ‘airfoil
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shaped rib’ in the wrong orientation (turned down towards the channel 50)
and incorporate it into Surace for the purpose of promoting heat transfer”).
Hall teaches that “[b]y moving the flow at an acute angle to the axial
direction, more channel length is created through which the flow must travel
before it is discharged” which increases “convective heat transfer” and that
“[secondary flows set up within the passages due to the turning further
enhances heat transfer.” Hall, col. 3,11. 28-33. As noted by the Examiner,
Surace likewise uses turbulence elements to promote heat transfer. Ans. 16
(citing Surace, col. 6,11. 21-27). Surace further teaches that turbulence
elements 48 can have different geometries. Id. (citing Surace, col. 6,11. 9-
12). The Examiner’s proposed modification is a predictable use of Hall’s
turbulence elements according to their established function for the same
purpose as the turbulence elements of Surace, i.e., to promote heat transfer.
See KSR Inti Co. v. Teleflex Inc., 550 U.S. 398, 417 (2007) (“if a technique
has been used to improve one device, and a person of ordinary skill in the art
would recognize that it would improve similar devices in the same way,
using the technique is obvious unless its actual application is beyond his or
her skill”). Appellants have not demonstrated that the Examiner relied on
impermissible hindsight in reaching a determination of obviousness of the
subject matter of claim 11. Accordingly, we sustain the rejection of claim
11, and claims 12, 14, and 16-18, which fall with claim 11, as unpatentable
over Surace and Hall.
Second Ground of Rejection of Claim 13 as Unpatentable over Surace, Hall,
and Cunha
Appellants do not address separately the second ground of rejection of
claim 13. Appeal Br. 5-7. Appellants appear to rely on the assertions of
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error in the Examiner’s findings as to Hall and the proposed combination of
Surace and Hall, discussed supra, as the basis for reversal of the rejection of
claim 13. For the reasons discussed above, we discern no error the
Examiner’s findings as to Hall or the proposed modification of Surace with
the teachings of Hall. As such, we sustain the rejection of claim 13.
Third Ground of Rejection of Claims 19-23 and 25-27 as Unpatentable
over Cunha and Hall
Independent claim 19 recites a casting core for producing a cast
turbine blade or vane comprising: (1) a first region in a vicinity of a casting
core trailing edge at which a plurality of first openings are arranged for
forming webs in the trailing edge of the turbine blade or vane, and (2) a
plurality of second openings arranged adjacent to the first region by means
of which a plurality of turbulence elements remain in the cast turbine blade
or vane. Appeal Br. 11 (Claims App.). Claim 19 further recites that “at least
one of the second openings is at least partially concavely shaped in order to
form correspondingly shaped, C-shaped turbulence elements in the turbine
blade or vane,” and “the concave part of the at least one second opening and
two arc ends of the C-shape of the at least one second opening face away
from the casting core trailing edge.” Id.
In this ground of rejection, the Examiner finds that Cunha discloses a
casting core for forming turbulence elements, and finds that Hall discloses
turbulence elements 46 of C-shaped design. Final Act. 12. The Examiner
proposes to modify the second openings of the casting core of Cunha by
constructing them with the shape of the turbulence elements of Hall. Id. at
12-13. The Examiner makes the same findings as to the disclosure of Hall
as set forth in the rejection of claim 11.
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Appellants rely on the same arguments presented in support of claim
11 as the basis for seeking reversal of the third ground of rejection. Appeal
Br. 5. We select claim 19 as representative of this group, and claims 20-23
and 25-27 stand or fall with claim 19. 37 C.F.R. § 41.37(c)(l)(iv). For the
reasons discussed supra, we discern no error in the Examiner’s findings that
Hall’s ribs 46 are C-shaped and are turbulence elements. Appellants’
argument about an increase in pressure loss does not apply to claim 19,
which does not contain this argued limitation. Further, Appellants’
argument against the proposed modification of Surace with Hall is also
inapplicable to the rejection of claim 19, which relies on Cunha as modified
by Hall. As such, Appellants have not demonstrated error in the rejection of
claim 19 as unpatentable over Cunha and Hall. Accordingly, we sustain the
rejection of claim 19, and claims 20-23 and 25-27, which fall with claim 19.
DECISION
The decision of the Examiner to reject claims 11-14, 16-23, and 25-
27 is affirmed.
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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