Ex Parte Ferber et al

Board of Patent Appeals and Interferences

Dec 29, 2004

09431178 (B.P.A.I. Dec. 29, 2004)

The opinion in support of the decision being
entered today was not written for publication
and is not binding precedent of the Board.

Paper No. 33

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte JORGEN FERBER and BERNHARD WEIGAND
____________

Appeal No. 2004-1622
Application No. 09/431,178
____________

HEARD: December 9, 2004
____________

Before FRANKFORT, STAAB and MCQUADE, Administrative Patent
Judges.

MCQUADE, Administrative Patent Judge.

DECISION ON APPEAL
Jorgen Ferber et al. appeal from the final rejection (Paper
No. 20) of claim 1, the sole claim pending in the application.

THE INVENTION
The invention relates to a component, e.g., a turbine blade,
having coolant passages for counteracting high thermal loading.
Claim 1 reads as follows:
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Application No. 09/431,178

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1. A component which can be subjected to high thermal
loading and to which a hot-gas flow can be admitted during
operation, the component comprising:

at least one hot-gas side for exposure to the hot-gas flow
and a cold-gas side not for exposure to the hot-gas flow;

component cooling passages connecting the hot-gas side and
the cold-gas side so that when a cooling medium flows from the
cold-gas side to the hot-gas side, the cooling medium, when
passing through a component passage, absorbs heat from the
component and draws off the heat to the hot-gas side;

wherein at least one of the component cooling passages has a
length, a hot-side orifice, a cold-side orifice, and a circular
cross section over the entire length of the at least one
component cooling passage, which cross section increases
continuously from the cold-gas side to the hot-gas side, the at
least one component cooling passage enclosing an opening half
angle so that the at least one component cooling passage is
frustoconical;

wherein the opening half angle of the at least one component
cooling passage is essentially constant over the length of the
passage;

wherein the opening half angle is between 0.2E and 2.5E; and

wherein a ratio of the cross-sectional area of the hot-side
orifice of the at least one component cooling passage to the
cross-sectional area of the cold-side orifice of the at least one
component cooling passage is less than 1.2.

THE EVIDENCE

The item relied on by the examiner as evidence of

obviousness is:

Howald 3,527,543 Sep. 08, 1970

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Application No. 09/431,178

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The item relied on by the appellants as evidence of non-
obviousness is:
The 37 CFR ' 1.132 Declaration of Rolf Dittmann filed January 24,
2002 (Paper No. 11).

THE REJECTION
Claim 1 stands rejected under 35 U.S.C. ' 103(a) as being
unpatentable over Howald.
Attention is directed to the main and reply briefs (Paper
Nos. 23 and 26) and the answer (Paper No. 24) for the respective
positions of the appellants and the examiner regarding the merits
of this rejection.1
DISCUSSION

1 In the answer (see page 6), the examiner asserts that the orifices of the instant
application (and presumably those set forth in claim 1) are inherently elliptical. This
assertion appears to be based on an assumption that the cooling passage orifices are
disposed on the airfoil of a turbine blade. Claim 1, however, is not so limited. The
underlying specification describes the turbine blade shown in the drawings merely as an
example of the sort of component addressed by the appellants, and indicates that
portions of the exemplary turbine blade other than the airfoil, such as the blade platform,
may contain cooling passages.
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Application No. 09/431,178

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As framed and argued by the appellants, the dispositive
issue in the appeal is whether Howald would have rendered obvious
within the meaning of ' 103(a) a component meeting the limitation
in claim 1 requiring that Aa ratio of the cross-sectional area of
the hot-side orifice of the at least one component cooling
passage to the cross-sectional area of the cold-side orifice of
the at least one component cooling passage is less than 1.2.@
The appellants do not dispute the examiner=s assessment that
Howald teaches, or would have suggested, a component meeting the
remaining limitations in the claim. Of the ratio in question,
the appellants= specification states that
[i]t proves to be favorable if the discharge cross
section of the cooling passage is less than 120% of the
inlet cross section, this on the one hand for
production reasons, so that the variation in the power
density of the cutting beam over the material thickness
to be penetrated is kept within practible limits, and
in order not require too short a focal width of the
collimating optics used [page 8].

The following passage from the Howald reference fairly

summarizes the component disclosed therein:

[b]riefly and in its broader aspects the invention
is characterized by a structural member, the Aouter@
surface of which defines a flow path for a hot gas
stream moving therepast at a relatively high velocity.
The opposite surface of this member defines, at least
in part, a chamber. Means are provided for
pressurizing a coolant, preferably air, within this
chamber to a pressure somewhat greater than the static
pressure of the gas stream flowing therepast. Discrete
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holes [44] are provided through the member so that the
coolant may flow from the pressurized chamber to the
Aouter@ surface thereof [column 2, lines 37 through
47].

Howald teaches that A[m]any interrelated factors contribute
to the effectiveness of the holes 44 in providing the desired
cooling action@ (column 5, lines 6 and 7). The factors discussed
include the cross-sectional shape of the holes, the diameter of
the holes, the angular disposition of the holes relative to the
outer surface, the arrangement of the holes on the outer surface,
the included angle of the holes, and the length to diameter ratio
of the holes (see, for example, column 2, line 53, through column
3, line 15; column 5, lines 7 through 18 and 62 through 68; and
column 6, lines 14 through 24).
Although Howald does not mention the ratio of the cross-
sectional areas of the hot-side and cold-side orifices as a
factor contributing to the effectiveness of the coolant holes,
the examiner submits that
[s]ince the originally filed disclosure of the
instant application fails to even mention any
criticality associated with the claimed range for the
abovementioned ratio of areas, it is reiterated that it
would not have been inventive to discover the optimum
range or another workable range for the abovementioned
ratio of areas by routine experimentation. . . .
It would thus have been obvious at the time of the
invention to perform routine experimentation in order
to optimize the relative areas of the hot-side orifice
and the cold-side orifice of Howald to a particular
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Application No. 09/431,178

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range of values, even to the range of between 1 and 1.2
as claimed by appellants in the instant application, in
order to optimize the performance of the structural
members or buckets being cooled while achieving
particular desired levels of entrainment of cooling
within the hot gas boundary layer, for example [answer,
page 5].

The examiner=s conclusion of obviousness ostensibly rests on
the well established principle that the discovery of an optimum
value of a variable in a known process is normally obvious, with
exceptions occurring where the parameter optimized was not
recognized to be a result effective variable or where the results
of optimizing a known result effective variable were unexpectedly
good. In re Antonie, 559 F.2d 618, 620, 195 USPQ 6, 8-9 (CCPA
1977).
In the present case, it is true that the ratio of the cross-
sectional areas of the hot-side and cold-side orifices depends on
some of the cooling effectiveness factors, e.g., length and
included angle of the hole, mentioned by Howald. Moreover, one
of ordinary skill in the art would have expected that changes in
these factors made to achieve a desired level of cooling
effectiveness would produce corresponding changes in the ratio of
the cross-sectional areas of the hot-side and cold-side orifices.
Howald, however, does not even mention this ratio, let alone
attach any importance thereto, in connection with the design of
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the coolant holes, and certainly does not contemplate the
specific manufacturing advantage disclosed by the appellants for
ratios less than 1.2. Thus, in the absence of impermissible
hindsight, Howald does not justify the examiner=s implicit
conclusion that the ratio of the cross-sectional areas of the
hot-side and cold-side orifices is an art-recognized result
effective variable relative to cooling effectiveness. Hence,
Howald fails to establish a prima facie case of obviousness with
respect to the subject matter recited in claim 1.2 Accordingly,
we shall not sustain the standing 35 U.S.C. ' 103(a) rejection of
this claim.

2 This being so, it is unnecessary to delve into the merits of the appellants=
evidence of non-obviousness.
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SUMMARY
The decision of the examiner to reject claim 1 is reversed.

REVERSED

CHARLES E. FRANKFORT )
Administrative Patent Judge )
)
)
)
) BOARD OF PATENT
LAWRENCE J. STAAB ) APPEALS
Administrative Patent Judge ) AND
) INTERFERENCES
)
)
)
JOHN P. MCQUADE )
Administrative Patent Judge )

JPM/gjh
Appeal No. 2004-1622
Application No. 09/431,178

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BURNS, DOANE, SWECKER & MATHIS LLP
POST OFFICE BOX 1404
ALEXANDRIA, VA 22313-1404

GJH

Appeal No. 2004-1622
Application No. 09/431,178

APJ MCQUADE

APJ STAAB

APJ FRANKFORT

REVERSED

September 15, 2005