Ex Parte Arthur et al

Board of Patent Appeals and Interferences

Mar 30, 2012

11238322 (B.P.A.I. Mar. 30, 2012)

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.
11/238,322 09/29/2005 David A. Arthur GP-306322 9141
65798 7590 03/30/2012
MILLER IP GROUP, PLC
GENERAL MOTORS CORPORATION
42690 WOODWARD AVENUE
SUITE 200
BLOOMFIELD HILLS, MI 48304
EXAMINER
CREPEAU, JONATHAN
ART UNIT PAPER NUMBER
1725
MAIL DATE DELIVERY MODE
03/30/2012 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 DAVID A. ARTHUR
and ABDULLAH B. ALP
__________

Appeal 2010-009276
Application 11/238,322
Technology Center 1700
___________

Before ADRIENE LEPIANE HANLON, CATHERINE Q. TIMM, and
MARK NAGUMO, Administrative Patent Judges.

HANLON, Administrative Patent Judge.

DECISION ON APPEAL

Appeal 2010-009276
Application 11/238,322

2

A. STATEMENT OF THE CASE
This is a decision on appeal under 35 U.S.C. § 134 from an Examiner’s
decision finally rejecting claims 1-15 under 35 U.S.C. § 103(a) as unpatentable
over the Appellants’ admitted prior art1 in view of Eisler.2,3 We have jurisdiction
under 35 U.S.C. § 6(b).
We REVERSE.
Claims 1 and 10, reproduced below, are the independent claims on appeal.
1. A fuel cell system comprising:
a split fuel cell stack including a first sub-stack and a second
sub-stack;
a first anode input line coupled to the first sub-stack;
a second anode input line coupled to the second sub-stack;
a connector line for connecting anode flow channels in the first
and second sub-stacks;
a hydrogen source for providing hydrogen gas to the first and
second anode input lines;
a first nitrogen bleed valve coupled to the first input line; and
a second nitrogen bleed valve coupled to the second input line,
wherein when the hydrogen source provides the hydrogen gas to the
first input line and a nitrogen bleed is requested, the first bleed valve
is closed and the second bleed valve is opened, and when the
hydrogen source provides the hydrogen gas to the second anode input
line and a nitrogen bleed is requested, the second bleed valve is closed
and the first bleed valve is opened.

1 The Examiner identifies Figure 1 of the Specification as the Appellants’ admitted
prior art (“AAPA”). See Examiner’s Answer dated May 11, 2010 (“Ans.”) at 3-5;
Appeal Brief dated March 15, 2010 (“App. Br.”) at 6.
2 US 2005/0129993 A1 published June 16, 2005.
3 Claims 16-20 are also pending but have been withdrawn from consideration.
Appeal
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Appeal 2010-009276
Application 11/238,322

4

The Examiner finds:
In Figure 1 of the instant specification, AAPA teaches a fuel
cell system comprising two substacks (14, 16) whose anode flow
fields are serially connected by a connector (26). Each substack
comprises a respective anode inlet line (22, 24). The system is
operated such that hydrogen is supplied to one substack, and then is
“flow-shifted” so that the hydrogen is supplied directly to the other
substack. Thus, the anode inlet lines function also as anode outlets
depending on the direction of flow.
Ans. 3-4. The Examiner finds that a nitrogen bleed valve (64) is positioned in the
connector line (26) between the two substacks (14, 16). Ans. 4.
The Examiner finds:
AAPA does not teach that a first nitrogen bleed valve is
coupled to the first input line, and that a second nitrogen bleed valve
is coupled to the second input line, as recited in claim 1, or that at
least one nitrogen bleed valve is provided in a line between the fuel
cell stack and the source, as recited in claim 10.
Ans. 4.
The Examiner also finds Eisler discloses a fuel cell system comprising a
valve (80) positioned in a recycle path between an anode outlet and an anode inlet.
The Examiner finds that the valve (80) bleeds hydrogen and contaminants, such as
nitrogen, from the anode line. Ans. 4; Eisler, paras. [0015], [0016].
The Examiner contends:
In [0007] and [0016], Eisler et al. teach that the accumulation of inert
gases such as nitrogen can degrade fuel cell performance. It would
have been obvious to provide a bleed valve such as that disclosed in
Eisler et al. in the locations of the system of AAPA corresponding to
the respective anode outlets in either flow direction (i.e., lines 22 and
24 in Figure 1).
Appeal 2010-009276
Application 11/238,322

5

Ans. 4-5; see also Ans. 7 (“[t]he present rejection is based on the premise that the
skilled artisan would be motivated to include a purge valve in any conduit that
functions as an outlet in AAPA, which includes lines 22 and 24, which correspond
to the claimed “input” lines).
The Appellants contend the Examiner has employed hindsight to arrive at
the subject matter recited in claims 1 and 10. App. Br. 9-10.
The Appellants’ argument is supported by the record. Eisler teaches that
contaminants, such as nitrogen, may accumulate in a fuel cell stack and degrade its
performance. Eisler, para. [0007]. Thus, Eisler includes a valve (80) between the
anode outlet and the anode inlet to maintain acceptable levels of contaminants in
the fuel cell stack. Eisler, para. [0015]. In contrast, the Examiner’s proposed
modification of AAPA would allow contaminants, such as nitrogen, to enter
downstream substack (14) or (16), depending on the direction of flow, before being
purged from anode line (22) or (24), respectively.
The Examiner also contends that AAPA expressly teaches that hydrogen is
disadvantageously purged from the nitrogen purge valve (64) located in the
connector line (26) and thus cannot be supplied to the downstream fuel cell
substack as useful fuel. Ans. 6. The Appellants contend the recognition of this
problem was their discovery. Reply Br. 1.4 In this regard, we note that Eisler also
discloses that hydrogen exits through the bleed flow path created by valve (80). In
particular, Eisler discloses that “[b]ecause the bleed flow is significantly smaller
than the flow exiting the anode exhaust port 57, only a small amount of fuel
(hydrogen) exits through the bleed flow path.” Eisler, para. [0015]. Significantly,
the Examiner has not directed us to any evidence demonstrating that, at the time of

4 Reply Brief dated June 14, 2010.
Appeal 2010-009276
Application 11/238,322

6

the Appellants’ invention, one of ordinary skill in the art would have recognized
that the effects of purging hydrogen through the nitrogen purge valve (64) of
AAPA or the purge valve (80) of Eisler outweigh the effects of contaminants in the
fuel cell stack.
Based on the foregoing, the preponderance of the evidence weighs in favor
of nonobviousness. Therefore, the § 103(a) rejection of claims 1-9 based on
AAPA in view of Eisler is reversed.
As for claim 10, the Examiner contends that once one of ordinary skill in the
art recognizes that anode lines (22) and (24) in AAPA function as outlets, it would
have been obvious to one of ordinary skill in the art to position a nitrogen bleed
valve in a line between a fuel cell stack and a hydrogen source. Ans. 7. For the
reasons set forth above, the preponderance of the evidence weighs against
positioning nitrogen bleed valves in the anode lines (22) and (24) of AAPA.
Therefore, the § 103(a) rejection of claims 10-15 based on AAPA in view of Eisler
is also reversed.
C. DECISION
The decision of the Examiner is reversed.

REVERSED

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