Ex Parte Meltser

Board of Patent Appeals and Interferences

Feb 28, 2011

10341765 (B.P.A.I. Feb. 28, 2011)

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.
10/341,765 01/14/2003 Mark A. Meltser 8540G-000143 9098
27572 7590 03/01/2011
HARNESS, DICKEY & PIERCE, P.L.C.
P.O. BOX 828
BLOOMFIELD HILLS, MI 48303
EXAMINER
DOVE, TRACY MAE
ART UNIT PAPER NUMBER
1726
MAIL DATE DELIVERY MODE
03/01/2011 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 MARK S. MELTSER
______________

Appeal 2009-009479
Application 10/341,765
Technology Center 1700
_______________

Before ADRIENE LEPIANE HANLON, CHARLES F. WARREN, and
CATHERINE Q. TIMM, Administrative Patent Judges.

WARREN, Administrative Patent Judge.

DECISION ON APPEAL1
Applicant appeals to the Board from the decision of the Primary
Examiner finally rejecting claims 20, 28, 42, 44, 46, and 49-51 in the Office
Action mailed December 28, 2007. 35 U.S.C. §§ 6 and 134(a) (2002);
37 C.F.R. § 41.31(a) (2008).

1 The two-month time period for filing an appeal or commencing a civil
action, as recited in 37 C.F.R. § 1.304, or for filing a request for rehearing,
as recited in 37 C.F.R. § 41.52, begins to run from the “MAIL DATE”
(paper delivery mode) or the “NOTIFICATION DATE” (electronic delivery
mode) shown on the PTOL-90A cover letter attached to this decision.

Appeal 2009-009479
Application 10/341,765
We affirm-in-part the decision of the Primary Examiner.
Claims 20, 42, and 44 illustrate Appellant’s invention of a method of
operating a fuel cell system, and are representative of the claims on appeal.
We have inserted system component numerals from Specification Figure 1
for clarity. See Spec. ¶¶0017-0027.
20. A method of operating a fuel cell system [20] comprising:
(a) selectively supplying hydrogen-containing anode effluent [32]
from an anode side of a fuel cell stack [22] to an accumulator [44];
(b) storing said anode effluent in said accumulator [44];
(c) routing said stored anode effluent [33] from said accumulator [44]
to a catalytic combustion device [51];
(d) maintaining a pressure difference between said accumulator [44]
and said anode side of said fuel cell stack [22] below a predetermined value;
(e) selectively mixing said hydrogen-containing anode effluent [33]
from said accumulator [44] with an oxidant-containing cathode effluent [34,
38] from a cathode side of said fuel cell stack [22] to form a fluid stream
[54];
(f) reducing a hydrogen content in said fluid stream [54] by
catalytically combusting a portion of said hydrogen in said fluid stream in
said catalytic combustion device [51];
(g) selectively supplying said fluid stream [54] from said catalytic
combustion device to said cathode side of said fuel cell stack [22];
(h) supplying an oxidant stream [30] to said cathode side of said fuel
cell stack [22]; and
(i) further reducing said hydrogen content in said fluid stream in said
cathode side of said fuel cell stack [22] by catalytically reacting said fluid
stream in said cathode side of said fuel cell stack [22],
wherein steps (e) and (f) are conducted essentially simultaneously by
mixing said anode effluent with said cathode effluent in a mixing chamber
[51] containing a catalyst [56] within said catalytic combustion device [51]
and maintaining said anode effluent and said cathode effluent separate from
one another until in the presence of said catalyst.
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42. A method of operating a fuel cell system [20] comprising:
(a) selectively mixing a hydrogen-containing anode effluent [32, 33]
from an anode side of a fuel cell stack [22] with an oxidant-containing
cathode effluent [34, 48] from a cathode side of a fuel cell stack [22] to form
a fluid stream [54];
(b) reducing a hydrogen content in said fluid stream by catalytically
combusting a portion of said hydrogen in said fluid stream in a catalytic
combustion device [mixer 51];
(c) selectively supplying said fluid stream [54] from said catalytic
combustion device to a cathode side of said fuel cell stack [22];
(d) supplying an oxidant stream to [30] said cathode side of said fuel
cell stack [22];
(e) further reducing said hydrogen content in said fluid stream in said
cathode side of said fuel cell stack [22] by catalytically reacting said fluid
stream in said cathode side of said fuel cell stack [22]; and
(f) maintaining a temperature of said fluid stream within said catalytic
combustion device [51] below a predetermined value by controlling a
quantity of said anode effluent mixing with said oxidant.
44. A method of operating a fuel cell system [20] comprising:
(a) selectively mixing a hydrogen-containing anode effluent [32, 33]
from an anode side of a fuel cell stack [22] with an oxidant-containing
cathode effluent [34, 38] from a cathode side of a fuel cell stack [22] to form
a fluid stream [54];
(b) reducing a hydrogen content in said fluid stream by catalytically
combusting a portion of said hydrogen in said fluid stream in a catalytic
combustion device [51];
(c) selectively supplying said fluid stream from said catalytic
combustion device to a cathode side of said fuel cell stack [22];
(d) supplying an oxidant stream [30] to said cathode side of said fuel
cell stack [22];
(e) further reducing said hydrogen content in said fluid stream in said
cathode side of said fuel cell stack [22] to less than about 4% by volume by
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Application 10/341,765
catalytically reacting said fluid stream in said cathode side of said fuel cell
stack.
Appellant requests review of the grounds of rejection under 35 U.S.C.
§ 103(a) advanced on appeal by the Examiner: claims 42, 44, and 46 over
Reiser (US 6,277,508 B1); and claims 20, 28, and 49-51 over Reiser in view
of Grasso (US 6,451,466 B1). App. Br. 11; Ans. 3 and 5.
Appellant argues the first ground of rejection based on claims 42, 44,
and 46; and argues the second ground of rejection based on claim 20. App.
Br., e.g., 12, 19, 22, 25, and 31. Thus, we decide this appeal based on claims
20, 42, 44, and 46. 37 C.F.R. § 41.37(c)(1)(vii) (2008).
Opinion
I. Claims 42, 46, and 44: Reiser
A. Claims 42 and 46
We interpret claim 42 to specify a method of operating a fuel cell
system comprising at least the steps of, among other things, mixing in any
manner a hydrogen-containing anode effluent with an oxidant-containing
cathode effluent to form a fluid stream; reducing the hydrogen content in the
fluid stream by catalytically combusting a portion of the hydrogen in any
manner of catalytic combustion device; and maintaining a temperature of the
fluid stream within the catalytic combustion device below a predetermined
value by controlling, in any manner, any quantity of the hydrogen-
containing anode effluent mixing with any amount of oxidant-containing
cathode effluent. Claim 46 further limits the method of claim 42 by
specifying that the predetermined temperature value is below that at which
“thermal combustion occurs.” Appellant defines “thermal combustion” as
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“flame combustion or propagation” which “can occur at about 800-900ºF”
when combustion device 51 has “a catalyst bed.” Spec. ¶¶ 0024-0025.
1. Claim 42
a.
Appellant submits that the Examiner erred in concluding that Reiser
would have rendered obvious the claimed method encompassed by claim 42
to one of ordinary skill in the art, arguing that the Examiner has not
established the motivation of one of ordinary skill in the art to practice the
claimed invention encompassed by claim 42 from the teachings of Reiser
that is necessary for a case of obviousness. App. Br. 12.
Appellant contends that Reiser “does not disclose the ability to control
the quantity of the anode effluent mixing with the oxidant” in the cathode
effluent exhaust as required by claim 42. App. Br. 12, emphasis in original;
see also App. Br. 14. According to Appellant, Reiser discloses that anode
effluent exhaust in line 60 is routed to either combustion unit 62 or vented
through valve 67. App. Br. 12-13, citing Reiser col. 5, ll. 34-37 and 47-48,
and Figs. 1 and 3; see Reply Br. 2. Appellant thus argues that anode effluent
exhaust in 60 is “either routed entirely to combustion unit 62, when valve 67
is closed, vented entirely through vent 67, when pump 63 is not operational,
or a combination of both.” App. Br. 13; see Reply Br. 3-4. Appellant
further contends that cathode effluent exhaust in line 49 can be routed in
three directions, including to combustion unit 62 through line 53. App. Br.
13, citing Reiser col. 4, ll. 11-16, and col. 6, ll. 28-30, and Figs 1 and 3; see
Reply Br. 3. According to Appellant, Reiser discloses that the cathode
effluent exhaust in line 53 mixes with the anode effluent exhaust in line 60
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upstream of combustion unit 62 and vent 67, and “does not disclose any type
of flow control device” to control the quantity of anode effluent exhaust
prior to combining with the cathode effluent exhaust. App. Br.
13-14, citing Reiser Figs 1 and 3.
On this basis, Appellant contends that all of the anode effluent exhaust
will mix with all of the cathode effluent exhaust, and thus “[t]he quantity of
the anode effluent is not controlled at all relative to the oxidant” in the
cathode effluent exhaust by Reiser. App. Br. 14. In this respect, Appellant
argues that Reiser’s valves 67 and 69 do not control the specific amount of
the anode effluent exhaust because valve 67 is positioned downstream after
the anode effluent exhaust and the cathode exhaust are combined, and valve
69 is downstream from combustion unit 62. App. Br. 14-15; see Reply Br.
3.
Appellant thus contends that, read as a whole, Reiser does not provide
any motivation or suggestion to control the quantity of anode effluent
exhaust mixing with the cathode effluent exhaust. App. Br. 15-16.
According to Appellant, Reiser teaches away from controlling the quantity
of the anode effluent exhaust by teachings that the anode effluent exhaust in
line 60 goes directly to combustion unit 62 along with all of the cathode
effluent exhaust flowing into line 60. App. Br. 16. Appellant thus argues
that Reiser only discloses the capability of limiting the quantity of cathode
effluent exhaust that flows into line 60, and thus, one of ordinary skill in the
art would not be motivated to control the quantity of the anode effluent
exhaust relative to the cathode effluent exhaust. App. Br. 16-17.
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Appellant further contends that Reiser fails to disclose maintaining a
temperature of the fluid steam within a catalytic combustion device below a
predetermined value by controlling the quantity of anode effluent exhaust
mixing with the cathode effluent exhaust as specified in claim 42. App. Br.
17-18. Appellant argues that the Examiner’s assertion that it would have
been obvious to one of ordinary skill from Reiser in the art to maintain a
temperature as claimed does not address maintaining the temperature by
controlling the quantity of anode effluent exhaust as claimed in applying
Reiser’s teachings, and thus is based on hindsight. App. Br. 17-19.
b.
The Examiner finds that Reiser would have disclosed, among other
things, that anode effluent exhaust and cathode effluent exhaust are mixed in
a catalytic combustion unit. Ans. 3, citing Reiser claims 16-17, col. 5,
ll. 30-64, and col. 6, ll. 25-35. The Examiner contends that it would have
been obvious from Reiser to maintain a temperature of the anode effluent
exhaust and cathode effluent exhaust fluid stream in the combustion unit by
controlling a quantity of the anode effluent exhaust mixing with the cathode
effluent exhaust as claimed. Ans. 4. The Examiner argues that one of
ordinary skill in the art would have recognized that catalytically reacting the
hydrogen in the anode effluent exhaust is exothermic, and thus would have
controlled the temperature of the combustor below a temperature at which
thermal combustion occurs by altering the amount of gas flow, “to prevent
the thermal combustion of the reactive gases prior to reaction at the
. . . catalyst” as taught in Reiser. Ans. 4 and 9-10.
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In response to Appellant’s position in the Appeal Brief, the Examiner
contends that Reiser discloses that valve 67, located prior to the combustion
unit, is used to vent anode effluent exhaust from the recycle loop, and that
“‘the combustion unit is preferably operated as near to stoichiometric as
possible to reduce the amount of oxygen introduced to the input fuel stream
and hence into the anode flow field.’” Ans. 8-9, citing Reiser col. 5 l. 32 to
col. 6, l. 35. On this basis, the Examiner argues that “[t]he ability to control
the quantity of the anode effluent mixing with the oxidant is clearly required
to operate as near to stoichiometric as possible,” and thus, one of ordinary
skill in the art would have been motivated to control the amount of the anode
effluent exhaust mixed with cathode effluent exhaust. Ans. 9. The
Examiner concludes that it would have been obvious to one of ordinary skill
in the art to maintain a temperature of the fluid steam “below a temperature
at which thermal combustion occurs, in order to prevent the thermal
combustion of the reactive gases prior to reaction at the . . . catalyst taught in
the reference,” and would have been “motivated to maintain the temperature
of the fluid stream below a value that combusts the fluids prior to entering
the catalytic combustor.” Ans. 10.
c.
Appellant replies that, among other things, Reiser’s disclosure to
operate the combustion unit as near to stoichiometric as possible, relied on
by the Examiner, is not relevant to the claimed invention encompassed by
claim 42 because the disclosure pertains to the embodiment shown in Reiser
Figure 2 wherein the stream from the combustion unit flows to anode flow
field 24, and not the cathode side of the fuel cell stack as claimed. Reply Br.
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Application 10/341,765
4-5. In this respect, Appellant further contends that even if this disclosure in
Reiser pertains to claim 42, it is not directed to controlling the quantity of
anode effluent exhaust mixed with the cathode effluent exhaust, but seems
“to apply to controlling the quantity of oxidant (cathode effluent) supplied
by line 53 and/or the direct input of air (which is not the cathode effluent),
into the combustion unit.” Reply Br. 5. Appellant thus argues that in
considering Reiser as a whole, one of ordinary skill in the art would not be
motivated to arrive at the claimed invention encompassed by claim 42
because Reiser “only discloses the possible controlling of the oxidant
(cathode effluent) which is not the controlling of the anode effluent.” Reply
Br. 6.
Appellant further contends that the Examiner has not addressed the
claimed invention encompassed by claim 42. Appellant argues that the
Examiner’s position is that the combined anode effluent exhaust and the
cathode effluent exhaust fluid stream is not heated “to a temperature for
thermal combustion before the combustion unit;” that it would have been
obvious to maintain the temperature of the fluid stream “to prevent the
thermal combustion of the reactive gases prior to reaction at the . . .
catalyst;” and that one of ordinary skill in the art would have been motivated
“to maintain the temperature of the fluid stream below a value that combusts
the fluids prior to entering the catalytic combustor.” Reply Br. 6-7
(emphasis in original), citing Ans. 10:8-9 and 10:9-15. Appellant points out
that claim 42 specifies “maintaining a temperature of said fluid stream
within said catalytic combustion device” as specified in claim 42, and “not
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‘before’ or ‘prior to’” as the Examiner contends. Reply Br. 7, emphasis in
original.
d.
There is no dispute that Reiser would have disclosed to one of
ordinary skill in the art a fuel cell system in which the entire anode effluent
exhaust from the fuel cell enters line 60 and is thence directed to combustion
unit 62 and/or is vented through vent valve 67. See Reiser, e.g., col. 5, ll.
31-55, col. 6, ll. 17-34, and Figs. 1 and 3. We fail to find in Reiser any
teaching that the fuel cell system should be operated in a manner that does
not supply a consistent quantity of anode effluent exhaust, regardless of the
hydrogen content thereof. See generally Reiser cols. 2-6. There is also no
dispute that Reiser teaches that a portion of all of the quantity of cathode
effluent exhaust from the fuel cell can be directed through line 53 to join line
60 upstream of combustion unit 62 and upstream of vent valve 67. See
Reiser, e.g., col. 5, l. 31-55, col. 6, ll. 17-34, and Figs. 1-3. We further find
that Reiser would have disclosed that combustion unit 62 can be, among
other things, a catalytic bed. Reiser col. 5, ll. 33-34, and Figs. 1-3. We also
find that Reiser would have disclosed that combustion unit 62 can be
“preferably operated as near to stoichiometric as possible to reduce the
amount of oxygen introduced into the input fuel steam 26” for anode flow
field 24, wherein vent valve 67 can provide one “option [for] venting at least
a portion of the anode exhaust.” Reiser col. 5, l. 67 to col. 6, l. 8, and Fig. 2.
We find that Reiser would have further disclosed that vent valve 67 can be
used alone to vary the amount of combusted exhaust from combustion unit
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62 that can be directed to cathode flow field 28 relative to anode flow field
24. Reiser col. 6, ll. 21-25 and Fig. 3.
We find that one of ordinary skill in the art would have recognized
that each of the fuel cell system embodiments illustrated in Reiser Figures 1-
3 has the same portion of the recycle loop that extends from anode flow field
24 through line 60 to combustion unit 62 and thence to condenser 68,
wherein line 60 connects with line 53 from line 25 from cathode flow field
28 and thence extends to vent valve 67. See Reiser cols. 3-6.
e.
On this record, we cannot agree with Appellant’s position that one of
ordinary skill in the art would not have been motivated by Reiser to practice
the method of operating a fuel cell system encompassed by claim 42, as we
have interpreted this claim above. See above p. 4. We agree with the
Examiner that, contrary to Appellant’s position, one of ordinary skill in the
art would have found in Reiser the suggestion that vent valve 67 can be used
to adjust the quantity of the anode effluent exhaust flowing through line 60
to combustion unit 62 if the entire flow of such exhaust from the fuel cell is
greater than desired. Indeed, Reiser would have taught one of ordinary skill
in the art that the quantity of anode effluent exhaust mixing with cathode
effluent exhaust can be controlled by directing all or only a portion of the
anode effluent exhaust, admixing with cathode effluent exhaust, through line
60 to combustion unit 62, which is all that claim 42 requires. In this respect,
and contrary to Appellant’s contentions, claim 42 further requires only
controlling the quantity of anode effluent exhaust “mixing” with cathode
effluent exhaust and not prior to “mixing” therewith, and there is no claim
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limitation proscribing adjusting the quantity of oxidant-containing cathode
effluent exhaust in response to changing concentrations of hydrogen in the
“quantity” of anode effluent exhaust.
We also cannot agree with Appellant’s position that one of ordinary
skill in the art would not have been motivated by Reiser to maintain the
temperature of the mixed anode effluent exhaust and the cathode effluent
exhaust fluid stream within combustion unit 62 below a predetermined level.
We agree with the Examiner that one of ordinary skill in the art would have
recognized that in Reiser’s fuel cell system, the temperature of the fluid
stream resulting from mixing a hydrogen-containing anode effluent exhaust
and an oxidant-containing cathode effluent exhaust should be maintained
within the combustion unit 62 below the temperature at which thermal
combustion, that is, flame combustion, occurs “to prevent the thermal
combustion of the reactive gases prior to reaction at the . . . catalyst.” Ans.
4. See above pp. 7. We cannot agree with Appellant that the Examiner’s
position in this respect is susceptible to a different interpretation than the
plain words in the statement of the ground of rejection convey. Reply Br. 6-
7. See above pp. 7-8.
In this respect, as the Examiner points out, one of ordinary skill in the
art would have recognized that in Reiser, the catalytic reduction of hydrogen
in the anode effluent exhaust is an exothermic reaction which can be
controlled by adjusting the flow of the mixed anode effluent exhaust and the
cathode effluent exhaust feed stream, and would have been taught by Reiser
that combustion unit 62 can be operated near stoichiometric by adjusting the
quantity of anode effluent exhaust directed to combustion unit 62 through
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line 60 with vent valve 67. Thus, one of ordinary skill in the art would have
further recognized that the extent to which the exothermic catalytic reduction
reaction is conducted in combustion unit 62 will, of course, determine the
operating temperature within combustion unit 62 and thus the temperature of
the mixed anode effluent exhaust and cathode effluent exhaust fluid stream
therein. We recognize that, as Appellant argues, Reiser discloses the
teaching of stoichiometric operation of combustion unit 62 in an
embodiment wherein the portion of the recycle loop remaining after
condenser 68 does not fall within claim 42 as Appellant argues. However,
we are of the opinion that one of ordinary skill in the art would find that
combustion unit 62 can be operated in similar manner in each of the three
illustrative embodiments, all of which have the same anode effluent exhaust
and cathode effluent exhaust feeds. See above p. 11.
2. Claim 46
Appellant further submits that the Examiner erred by misapplying
Reiser to claim 46 based on the allegation that Reiser’s “combustion unit 62
is taught to be a burner or catalytic bed, not a heating device to thermally
combust the reactants.” App. Br. 20. According to Appellant, Reiser’s
combustion unit 62 “does (or is at least capable of) thermally combusting the
fluid stream,” and Appellant discloses “that thermal combustion is
equivalent to flame combustion or propagation,” arguing that Reiser
“specifically teaches that the combustion unit 62 can be a burner or catalytic
bed.” App. Br. 21, citing Spec. ¶ 0025, ll. 8-10. “Appellant’s catalytic
combustion device is disclosed as containing a catalyst, such as a catalytic
bed.” App. 21, citing Spec. ¶ 0024. Appellant contends that since Reiser
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discloses “that the combustion unit can be a catalytic bed – it too can have
thermal combustion occurring therein,” and “a burner can also have thermal
combustion therein, such as flame ignition, because it is a burner and that is
what a burner does.” App. Br. 21.
We cannot subscribe to Appellant’s position. We find that Reiser
would have disclosed to one of ordinary skill in the art that combustion unit
62 can be “a burner or a catalyst bed.” Reiser col. 5, ll. 33-34, and Figs.
1-3. See above p. 10. We thus agree with the Examiner’s finding that
combustion unit 62 can be a catalytic combustion unit, and such a unit
would not include “a burner” component. Ans. 11. We agree with
Appellant that thermal, that is flame, combustion can occur at a catalyst bed.
However, we remain of the view that, as the Examiner contends, one of
ordinary skill in the art would have operated Reiser’s fuel cell system in a
manner that avoids flame combustion within catalytic combustion unit 62.
See above pp. 12-13.
B. Claim 44
We interpret claim 44 to specify a method of operating a fuel cell
system comprising at least the steps of, among other things, mixing a
hydrogen-containing anode effluent with an oxidant-containing cathode
effluent to form a fluid stream, reducing the hydrogen content in the fluid
stream by catalytically combusting a portion of the hydrogen in a catalytic
combustion device, supplying the fluid stream from the catalytic combustion
device and an oxidant stream to the cathode side of the fuel cell, and further
catalytically reducing said hydrogen content in the fluid stream in the
cathode side to less than about 4% by volume.
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1.
Appellant characterizes the method of claim 44 as a two-stage
catalytic reduction of hydrogen content of anode effluent exhaust, wherein
the first stage is conducted in the catalytic combustion device, and the
second stage is conducted in the cathode side of the fuel cell, and wherein
the second stage is conducted to the extent that the hydrogen content is
reduced to less than about 4% by volume. App. Br. 22-23. See Spec.
¶¶ 0025-0026.
Appellant submits that the Examiner erred in concluding that Reiser’s
disclosure provides motivation to support a case of obviousness of the
claimed two-stage hydrogen reduction method encompassed by claim 44.
App. Br. 23-25; Reply Br. 10-11. According to Appellant, Reiser is
concerned with forming water in combustor unit 62 which can be routed to
the cathode side of the fuel cell. App. Br. 23. Appellant argues that Reiser
thus “would appear to desire that all of the hydrogen in the anode exhaust be
converted to water” such that hydrogen in “the cathode flow fuel would be
undesirable” as it would consume oxidizer, thereby reducing fuel cell
voltage output, which is a one-stage hydrogen reduction method. App. Br.
23-24; Reply Br. 10. Appellant points out that the Examiner finds that
Reiser discloses that “combustion unit 62 is operated near stoichiometric to
prevent hydrogen from entering the cathode,” and argues that one of
ordinary skill in the art would thus not be motivated to provide hydrogen to
the cathode side of the fuel cell. App. Br. 24.
2.
The Examiner finds that “Reiser teaches combusting the anode
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exhaust gas to lower the amount of hydrogen and increase the amount of
water in the recirculated fluid.” Ans. 4. The Examiner determines that it
would have been obvious to one of ordinary skill in the art from Reiser to
reduce hydrogen content in the anode exhaust to less than about 4% by
volume because hydrogen is not a reactant on the anode side of the fuel cell
and the combustion unit is operated at near stoichiometric. Ans. 4-5 and 12.
The Examiner further finds that “[a]ny hydrogen entering the cathode side of
the fuel cell will inherently be catalyzed at the cathode catalyst.” Ans. 5 and
12-13. In response to Appellant’s position, the Examiner contends that
Appellant’s admission that Reiser desires the conversion of all hydrogen to
water supports the Examiner’s position that Reiser would reduce the amount
of hydrogen to less than 4%. Ans. 12; see also Ans. 13. The Examiner thus
maintains that Reiser would have taught a two-stage reduction of hydrogen
content as claimed. Ans. 12-13.
3.
On this record, we agree with the Examiner’s position. Indeed, claim
44 specifies that hydrogen content in the fluid stream in the cathode side of
the fuel cell stack is reduced at least to the extent of less than about 4% by
volume. We find no limitation in claim 44 which specifies the hydrogen
content of the fluid stream from the catalytic combustion device prior to
entering the cathode side of the fuel cell stack. Thus, we agree with the
Examiner that Appellant’s arguments establish that one of ordinary skill in
the art following Reiser’s method of operating the fuel cell system disclosed
therein reasonably would have reduced the hydrogen content of the fluid
stream to less than about 4% by volume in the cathode side of the fuel cell
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stack as claimed. Indeed, the “less than about 4% by volume” limitation of
claim 44 is met when the hydrogen content of the fluid stream from the
catalytic combustion device has a hydrogen content of less than about 4% by
volume before it enters the cathode side of the fuel cell stack.
C.
Accordingly, based on our consideration of the totality of the record
before us, we have weighed the evidence of obviousness found in the
teachings of Reiser with Appellant’s countervailing evidence of and
argument for nonobviousness and conclude, by a preponderance of the
evidence and weight of argument, that the claimed invention encompassed
by appealed claims 42, 44, and 46 would have been obvious as a matter of
law under 35 U.S.C. § 103(a).
II. Claims 20, 28, and 49-51: Reiser and Grasso
The dispositive issue in this ground of rejection is whether one of
ordinary skill in the art would have combined Reiser and Grasso, and thence
would have modified Reiser’s fuel cell system by inserting an accumulator
in line 60 between anode flow field 24 and combustion unit 62, wherein the
accumulator stores anode effluent exhaust and releases it in line 60 to
combustion unit 62 while a pressure difference between the accumulator and
the anode flow field is maintained below a predetermined level, as specified
in representative independent claim 20.
We find that Grasso would have disclosed to one of ordinary skill in
the art a fuel cell system in which hydrogen-containing anode effluent
exhaust is routed from anode side 30 of fuel cell 20 to burner 70 wherein the
hydrogen content is reduced with an oxidant to produce steam for the fuel
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processing system. Grasso col. 7, ll. 31-48, and Fig. 1. Grasso discloses that
burner exhaust stream 75 containing water vapor (steam) is combined with
the oxidant exhausted from cathode side 40 of fuel cell 20 in the coolant
loop, wherein the fluid stream is directed to degasifier 80 which, among
other things, strips contaminates from the coolant water in the coolant loop.
Grasso col. 7, ll. 28-33, and Fig. 1; see also, e.g., col. 6, ll. 13-27, col. 8, l.
62 to col. 9, l. 65, and Fig. 2. Grasso discloses “an accumulator 90 for
providing a reservoir within which excess water may be stored for
subsequent use, upon demand, by the fuel cell assembly 20,” wherein the
accumulator 90 receives cleansed coolant water from degasifier 80 and can
be separate from or in a common housing with degasifier 80. Grasso col. 7,
ll. 34-36 and 40-45, col. 10, ll. 31-39, and Figs. 1 and 2; see also, e.g., col. 8,
l. 62 to col. 9, l. 65.
On this record, we agree with Appellant’s position that Grasso’s
accumulator in the fuel cell system illustrated in that reference does not
occupy the same position or perform the same functions specified for the
accumulator in the claimed method encompassed by claim 20. App. Br.
6-28; Reply Brief 11-13. While we agree with the Examiner that
accumulators are well known in the art, the evidence in Grasso establishes
only that it was known in the art to use an accumulator to store excess
cleaned coolant water from a degasifier for subsequent release to the fuel
cell. Ans. 6 and 13-16. Thus, the Examiner has not established that one of
ordinary skill in the art would have modified Reiser’s fuel cell system with
an accumulator and would have operated the accumulator in the manner
claimed in claim 20.
18
Appeal 2009-009479
Application 10/341,765
Accordingly, in the absence of a case of obviousness, we reverse the
ground of rejection of claims 20, 28, and 49-51 under 35 U.S.C. § 103(a).
The Primary Examiner’s decision is affirmed-in-part.

No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a)(1)(iv).
AFFIRMED-IN-PART

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HARNESS, DICKEY & PIERCE, P.L.C.
P.O. BOX 828
BLOOMFIELD HILLS, MI 48303
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