Ex Parte Correia et al

Patent Trial and Appeal Board

Mar 26, 2013

11602137 (P.T.A.B. Mar. 26, 2013)

UNITED STATES PATENT AND TRADEMARK OFFICE
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BEFORE THE PATENT TRIAL AND APPEAL BOARD

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Ex parte VICTOR HUGO SILVA CORREIA,
ROBERT FRANCIS MANNING, and
BHANU MAHASAMUDRAM REDDY
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Appeal 2011-000028
Application 11/602,137
Technology Center 3700
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Before CHARLES N. GREENHUT, BARRY L. GROSSMAN, and
TIMOTHY J. O’HEARN, Administrative Patent Judges.

GROSSMAN, Administrative Patent Judge.

DECISION ON APPEAL

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STATEMENT OF THE CASE
Appellants appeal under 35 U.S.C. § 134 from the Examiner’s
decision finally rejecting claims 1-3, 11-16, and 26-28. We have jurisdiction
over the appeal under 35 U.S.C. § 6(b).
We AFFIRM.
CLAIMED SUBJECT MATTER
Claims 1 and 11 are the independent claims on appeal. Claim 1 is
illustrative of the subject matter on appeal, and recites:
1. A turbine blade comprising forward and aft
serpentine cooling circuits, terminating in
corresponding forward and aft impingement
channels, with each circuit having two metered
inlets for distributing more inlet flow to first passes
thereof than to last passes thereof.

REFERENCES
The Examiner relied upon the following prior art references:

REJECTIONS
Appellants seek review of the rejections of claims 1, 2, and 11 under
35 USC § 103(a) based on Moskowitz, Doughty, and Starkweather.
ANALYSIS
Claims 1, 2, and 11
Appellants argue the claims collectively (e.g., App. Br. 11, 12, 15, 16)
and we consider then collectively, unless specific reference to a claim
limitation is required.
Moskowitz US 3,706,508 Dec. 19, 1972
Doughty US 6,126,396 Oct. 3, 2000
Starkweather US 2002/0119045 A1 Aug. 29, 2002
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The Examiner found that Starkweather discloses the basic structure of
a turbine blade, as called for in the claims, including forward and aft
serpentine cooling circuits, forward and aft impingement channels, and
metering plates to adjust the amount of cooling flow through two of the four
inlets to the cooling circuits, i.e., inlets 68 . The Examiner recognized that
Starkweather does not disclose a metering plate covering the other two
inlets, i.e., inlets 37. Ans. 3-4.1 The Examiner also found that Moskowitz
teaches a metering plate for use on a turbine airfoil wherein the orifices of
the metering plate are sized to meet the cooling requirements of the blade in
differing temperature and pressure environments. Id. at 4. Appellants’
arguments refer to this as a “special” metering configuration that distributes
more flow to one part of the turbine blade than another. App. Br. 17.
Additionally, the Examiner found that Doughty teaches an aft impingement
cooling circuit in a turbine airfoil. Id. at 5.
Based on these finding, the Examiner concluded that it would have
been obvious at the time the invention was made to one of ordinary skill in
the art to modify the cooling circuit of Starkweather with the teachings of
Moskowitz by providing a metering plate over all four cooling holes for the
purpose of metering the cooling flow into the circuit. Ans. 5. The Examiner
also concluded that it would have been an obvious matter of engineering
design choice to size the openings in the metering plate to correspond to the
amount of cooling flow desired to pass through each of the inlet. Id.
Additionally, the Examiner concluded that it would have been obvious
at the time the invention was made to one of ordinary skill in the in art to

1 Citations to “Ans. ___” are to the indicated page in the Examiner’s Answer
mailed July 21, 2010.
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further modify the cooling circuit of Starkweather with an aft impingement
cooling circuit, as disclosed in Doughty. Id. The rationale provided by the
Examiner for the proposed modification was that it was for the purpose of
cooling the trailing edge of the airfoil. Id.
Appellants argue extensively and in great detail about the alleged
errors in the rejections, but the errors they argue can be summarized as the
following:
1. The rejections fail to consider the invention as a whole (Reply Br.
2)2;
2. The rejections are not supported by the evidence (Id. at 4); and
3. The rejections rely on hindsight analysis to selectively glean
disparate elements from the prior art and combine them (Id. at 3, 5).
Appellants sum up their "disagreement" with the rejections as being
based solely on the inadequacy of the evidence available in the applied
references, and the proper evaluation of such evidence under the applicable
legal standards under Section 103. App. Br. 29. We first address the alleged
inadequacy of the evidence.
The Applied References
The inventions disclosed in Starkweather, Moskowitz, and Doughty
all deal with cooling systems for a turbine blade.
Starkweather
As found by the Examiner (Ans. 3-4), Starkweather discloses cooling
air circuits of turbine rotor blades and stator vanes in gas turbine engines
and, more specifically, to metering plates to meter flow to the cooling

2 Citations to “Reply Br. ___” are to the indicated page in the Reply Brief
filed July 26, 2010.
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circuits within turbine blades. Starkweather, [0002]. Starkweather clearly
discloses a forward flowing serpentine cooling circuit and an aft flowing
serpentine cooling circuit located within the airfoil. Id. at [0013], as called
for in the claims. Starkweather further discloses a metering plate covering
an inlet to the refresher passageway, with the metering plate having an
adjustable metering hole over the inlet. Id. at [0012]. The metering plates
are adjustable and, therefore, can be used to adjust amount of cooling flow.
Id. at [0014]. This is the same function disclosed in Appellants’
Specification for the metering plate called for in the claims. As disclosed in
the Specification, metering plate 52 covers the four inlet channels 44-50 and
preferentially distributes or meters the cooling flow differently through the
four inlet channels to control the different cooling performance in the
forward and aft portions of the airfoil. Spec. [0041].
The claims require that each of the forward and aft cooling circuits
have two metered inlets. Starkweather discloses two inlets for each of the
forward and aft cooling circuits but only meters one of the two inlets for
each circuit. Appellants argue that “Starkweather clearly teaches that no
metering orifice is required or desired for the two central entrances 37.”
App. Br. 30 (emphasis added). We find no evidence for this position in the
record and Appellants have not pointed us to any such evidence. Rather
than preclude additional metering of the inlets 37, Starkweather discloses
that any other conventional features for enhancing the cooling of the turbine
blade disclosed in the preferred embodiment may be used. Starkweather,
[0029].
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Moskowitz
Moskowitz recognizes the general problem that in a gas turbine
engine there are gradients of temperature in a turbine blade (col. 1, ll. 30-
35). Moskowitz also recognizes that the flow of coolant air to the blades
may be nonuniform, owing to varying degrees of intricacy in the flow path
the air must follow to reach the various blades, or to their varying distances
from the source of cooling air (col. 1, ll. 35-39). To overcome this problem,
Moskowitz provides coolant channels of different cross-sections distributed
across the chord of the blade, in order to accommodate both temperature and
pressure gradients across the chord. Moskowitz also provides a metering
plate at the base of each blade covering all the inlets whereby a selected
amount of coolant can be fed to each blade passage (col. 1, l. 65 – col. 2, l.
6). As found by the Examiner, the object of the Moskowitz disclosure is to
provide a means of metering an appropriate amount of coolant to selected
portions of a turbine stator blade. This is exactly the same as what
Appellants assert is a “special” metering configuration in the claimed
invention that distributes more air flow to one part of the blade than another.
App. Br. 17. As recognized by Appellants (App. Br. 30), Moskowitz
discloses that the leading edge of the blade is commonly the hottest portion
and may therefore require the greatest flow of coolant (col. 3, ll. 43-45).
Moskowitz also discloses how more, or less, coolant for one or more
passages can be obtained by adjusting the flow through the metering plate
(col. 4, ll. 8-29).
Doughty
Doughty relates generally to cooling air circuits of turbine rotor blades
and stator vanes in gas turbine engines and, more specifically, to serpentine
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cooling circuits feeding cooling air to side wall impingement cooling
chambers (col. 1, ll. 11-15). Doughty also summarizes the various known
turbine airfoil cooling techniques available to a person of ordinary skill in
the relevant technology to use as appropriate in various situations. These
known cooling techniques include the use of internal cavities forming a
serpentine cooling circuit, leading edge impingement bridges, film holes, pin
fins, and trailing edge holes or pressure side bleed slots (col. 2, ll. 45-54).
Thus, as found by the Examiner, the applied references collectively
disclose all of the argued structural and functional limitations recited in the
claims – forward and aft serpentine cooling circuits and metering plates
covering all or some of the inlets for adjusting the flow of coolant to
distribute more cooling flow to the areas most in need of coolant.
Based on Appellants’ arguments, we find no error in the Examiner’s
findings about the evidence.
Appellants also argue the proper evaluation of the evidence under the
applicable legal standards under Section 103 (App. Br. 29), which we
address below.
The Examiner’s Combination of the References
Appellants’ primary dispute is the rationale for the Examiner’s alleged
hindsight, selective combination of elements from three references and
further modified with alleged conclusions about “design choice.” E.g.,
Reply Br. 5.
Appellants argue that the Starkweather, Doughty, and Moskowitz are
fundamentally different from each other, and address different problems
with different solutions. Appellants assert that the Examiner has only found
“naked elements” in disparate references; and combined them in “classic
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hindsight” with rote assertions lacking the requisite legal motivation
mandated by Section 103, and KSR. App. Br. 32.
We agree that the references are different from each other and from
the claimed invention, but this is not the proper focus. If the references were
identical to the claimed invention, the proper rejection would have been
under Section 102 based on anticipation, not Section 103 based on
obviousness. While Appellants point out various differences between the
applied references and the claimed invention, they fail to see the numerous
similarities. Non-obviousness cannot be established by attacking references
individually where the rejection is based upon the teachings of a
combination of references. In re Merck & Co., Inc., 800 F. 2d 1091, 1097
(Fed. Cir. 1986). Thus, the references must be read, not in isolation, but for
what they collectively teach to a person of ordinary skill.
In KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398, 415 (2007), the
Supreme Court reaffirmed “the need for caution in granting a patent based
on the combination of elements found in the prior art,” and discussed
circumstances in which a patent might be determined to be obvious. In
particular, the Supreme Court emphasized that “[t]he combination of
familiar elements according to known methods is likely to be obvious when
it does no more than yield predictable results.” KSR, 550 U.S. at 416. The
Court explained:
“. . . 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.”
Id. at 417.
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The operative question is thus “whether the improvement is more than
the predictable use of prior art elements according to their established
functions.” Id.
As the Supreme Court explained in KSR, “[o]ften, it will be necessary
for a court to look to interrelated teachings of multiple patents; the effects of
demands known to the design community or present in the marketplace; and
the background knowledge possessed by a person having ordinary skill in
the art, all in order to determine whether there was an apparent reason to
combine the known elements in the fashion claimed by the patent at issue.”
Id. at 418. That is what the Examiner did here. As found by the Examiner,
Appellants’ claims 1, 2, and 11 are combinations which unite old elements
with no change in their respective functions and which yield predictable
results. The modifications proposed by the Examiner, providing adjustable
metering plates over all cooling holes and adjusting the adjustable metering
plate to correspond to the flow desired, are suggested in the references.
In addition, neither Appellants’ Specification nor Appellants’
arguments present any evidence that the modifications necessary to effect
the combination are uniquely challenging or difficult for one of ordinary
skill in the art. The Court in KSR noted that “[a] person of ordinary skill is
also a person of ordinary creativity, not an automaton.” 550 U.S. at 421. It
would take no more than ordinary creativity for a person of ordinary skill to
adapt the metering plate of Moskowitz and the cooling circuit of Doughty to
the basic turbine blade cooling system in Starkweather, as proposed by the
Examiner. As stated in KSR, “in many cases a person of ordinary skill will
be able to fit the teachings of multiple patents together like pieces of a
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puzzle.” KSR, 550 U.S. at 420. That is what the Examiner concludes here,
and it clearly is supported by the applicable law and the applied references.
Appellants argue that in Starkweather and Doughty the cooling
circuits are disposed in series, and therefore are mutually interdependent. In
Moskowitz, the cooling channels are disposed in parallel, and therefore
operate independently. App. Br. 30. Appellants assert that independent
operation allows those channels to have differently sized inlets. Contrary to
the implication in Appellants’ assertion, the obviousness inquiry does not
ask "whether the references could be physically combined but whether the
claimed inventions are rendered obvious by the teachings of the prior art as a
whole." In re Etter, 756 F.2d 852 (Fed. Cir. 1985) (en banc); see also In re
Keller, 642 F.2d 413, 425 (CCPA 1981) (stating "[t]he test for obviousness
is not whether the features of a secondary reference may be bodily
incorporated into the structure of the primary reference"). Rather, in a case
such as this, where each of the elements of the claim are known to the art,
the obviousness inquiry requires a conclusion that the combination of known
elements was obvious to a person with ordinary skill in the art. Appellants'
arguments have not apprised us of any error in the rejection of claims 1, 2,
and 11.
Under the facts and evidence in this case, and applying the applicable
legal standards, the Examiner did not err in holding that it would have been
obvious to one having ordinary skill in the art at the time the invention was
made to modify the cooling circuit of Starkweather with the teachings of
Moskowitz and Doughty.
Only those arguments actually made by Appellants have been
considered in this decision. Arguments which Appellants could have made
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but chose not to make in the Briefs have not been considered and are
deemed to be waived. See 37 C.F.R. § 41.37(c)(1)(vii).
DECISION
Upon consideration of the record as a whole in light of Appellants’
contentions and the preponderance of relevant evidence, we AFFIRM the
rejections of claims 1, 2, and 11.
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

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