Ex Parte Breault

Board of Patent Appeals and Interferences

Aug 29, 2008

10649244 (B.P.A.I. Aug. 29, 2008)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte RICHARD D. BREAULT
__________

Appeal 2008-5002
Application 10/649,244
Technology Center 1700
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Decided: August 29, 2008
____________

Before CHARLES F. WARREN, TERRY J. OWENS, and
MICHAEL P. COLAIANNI, Administrative Patent Judges.

COLAIANNI, Administrative Patent Judge.

DECISION ON APPEAL
Appellant appeals under 35 U.S.C. § 134 the final rejection of claims
12-21. We have jurisdiction over the appeal pursuant to 35 U.S.C. § 6(b).
Appeal 2008-5002
Application 10/649,244

We AFFIRM-IN-PART.

INTRODUCTION
Appellant claims a process of cooling fuel cells by evaporative
cooling during fuel cell operation comprising, in relevant part, providing a
barrier layer between a water channel and a steam channel, causing the
liquid water to boil by reducing the pressure in the steam channel and
condensing the steam outside the fuel cell and recirculating a portion of the
condensed steam back to the flowing liquid water, wherein the steam
originated as the flowing liquid water converted into steam and passed the
barrier layer into the steam channel (claim 12). Appellant further claims a
method of evaporatively cooling a plurality of adjacent fuel cells including,
in relevant part, the step of drawing a vacuum in second channels (i.e., the
steam channels) to reduce the pressure in the second channels to below the
vapor pressure of water in the first channels to cause the liquid water to boil
and produce steam that passes through the barrier layer into the second
channel (claim 16).
Claims 12 and 16 are illustrative:
12. In a stack of fuel cells, wherein adjacent cells are separated by a
porous, hydrophobic barrier layer having a water intrusion pressure
that prevents liquid water from crossing between cells through the
barrier layer under normal operating conditions, the cell on one side of
the barrier layer defining a flow channel for liquid water adjacent that
one side of the barrier layer, the cell on the other side of the barrier
layer defining a flow channel for steam adjacent that other side of the
barrier layer, said water and steam flow channels being in vapor
communication with each other through the barrier layer, the process
of cooling the fuel cells by evaporative cooling during fuel cell
operation comprising the steps of:

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flowing liquid water into and through the water flow channel
and out of the fuel cell, the water being heated within the water
channel by heat produced by the fuel cell;

causing the liquid water to boil as it flows through the water
channel by reducing the pressure in the steam channel below the
vapor pressure of the flowing liquid water to convert at least some of
the water to steam that passes through the barrier layer into the steam
channel, wherein the pressure in the steam channel is increased or
decreased during cell operation in response to the operating
temperature of the cell to increase or decrease the operating
temperature of the cell to achieve a desired cell operating temperature;
and

condensing the steam outside the fuel cell and recirculating a
portion of the condensed steam back to the flowing liquid water,
wherein the steam originated as the flowing liquid water converted
into steam and passed through the barrier layer into the steam channel.

16. A method for evaporatively cooling a plurality of adjacent fuel
cells, wherein each cell comprises an electrolyte layer sandwiched
between a porous anode water transport plate and a porous cathode
water transport plate, the anode plate of one cell extending from the
electrolyte layer of the cell to one side of a porous hydrophobic,
electrically conductive barrier layer separating the two adjacent cells,
and the cathode plate of the adjacent cell extending from the
electrolyte layer of said adjacent cell to the other side of said barrier
layer, the steps of:

a) flowing liquid water adjacent one side of the barrier layer
through first channels formed between one of the cell water transport
plates and the barrier layer;

b) drawing a vacuum in second channels formed between the
transport plate of the adjacent cell and the other side of the barrier
layer to reduce the pressure in the second channels to below the vapor
pressure of the water in the first channels to cause the liquid water to
boil and produce steam that passes through the barrier layer into the
second channels;
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c) removing the steam from the second channels; and

d) controlling the amount of evaporative cooling by controlling
the steam pressure in the second channels.

The Examiner relies on the following prior art reference as evidence
of unpatentability:
Stedman 3,704,172 Nov. 28, 1972

The rejection as presented by the Examiner is as follows:
1. Claims 12-21 are rejected under 35 U.S.C. § 103(a) as being
unpatentable over Stedman.

Appellant separately argues claims 12 and 16. Pursuant to 37 C.F.R. §
41.37(c)(1)(vii), we address Appellant’s arguments and evidence with
respect to the above rejection with regard to claims 12 and 16.

OPINION
With regard to claim 12, Appellant argues that Stedman discloses
using a closed-cycle cooling mode and an open-cycle (i.e., evaporative)
cooling mode that vents the coolant to the atmosphere such that combining a
radiator/condenser with open-cycle cooling mode would render Stedman’s
device inoperable for its intended purpose (Br. 11, 16). With regard to claim
16, Appellant argues that Stedman is silent with respect to drawing a
vacuum so as to cause the coolant water to boil, form steam, and
evaporatively cool the fuel cell stack as required by the claim (Br. 14, 15).
Appellant provides a copy of the Declaration of Gregory Reynolds
(hereinafter the Reynolds Declaration) filed January 8, 2007, which was
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considered by the Examiner, refuting the Examiner’s findings regarding the
Stedman reference.
Stedman discloses a dual mode fuel cell system having a closed-cycle
cooling mode and an open-cycle cooling mode (Stedman, col. 1, ll. 23-27).
The closed-cycle cooling mode uses a circulating coolant to remove heat
from the fuel cell stack, while the recovered electrolyte diluent is stored for
use during the open-cycle cooling mode (Stedman, col., 1, ll. 56-60). In the
open-cycle cooling mode electrolyte diluent carried by a stream of
recirculating reactant gas is vented overboard; venting starts whenever
diluent must be removed at a rate higher than the rate the closed-cycle
electrolyte diluent removal subsystem can handle (Stedman, col. 1, ll. 61-
67). During the open-cycle cooling mode, heat is removed by evaporation
and venting of the stored liquid electrolyte diluent (Stedman, col. 1, ll. 67-
68). Stedman discloses that the dual mode has flexibility from the capability
of the system to reject waste heat either by vapor venting or radiator means
(Stedman, col. 2, ll. 1-3). Stedman discloses that the dual mode system is
advantageous for space shuttle vehicles where the heat removal by a radiator
is not possible on reentry or satellites where space for radiator heat removal
areas are limited (Stedman, col. 2, ll. 4-6).
Stedman further discloses that the open-cycle mode evaporatively
cools the fuel cell by feeding the condensed and accumulated diluent in
liquid storage means 62 through an inlet 32, which crosses an evaporative
cooling means 30, and exits from the fuel cell via outlet 34 (Stedman, col. 2,
ll. 70-72). The closed-cycle mode feeds cooling water to the fuel cell stack
through an inlet 26 and the cooling water exits the stack at outlet 28
(Stedman, col. 2, ll. 68-70). Stedman discloses that the closed-cycle coolant
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loop 42 has a heat exchange means 46 (e.g., a radiator), fan 48 and an
accumulator 39, such that the coolant is cooled by the fan to lower the
temperature thereof (Stedman, col. 3, ll. 8-19). Stedman further discloses
that the diluent is vented in open-cycle mode by sensing the humidity of the
diluent stream with sensor 82 and venting via valve 84 as a function of the
humidity sensed (Stedman, col. 3, ll. 65-75; col. 4, ll. 1-5). Stedman
discloses using a condenser 56 to condense the diluent and store it in liquid
storage means 62 for use in the open-cycle mode (Stedman, col. 3, ll. 23-35).
A claimed invention that merely rearranges old elements with each
performing the same function it has been known to perform and yields no
more than what one would expect from such an arrangement would have
been obvious. KSR Int’l Co. v. Teleflex Inc., 127 S. Ct. 1727, 1740 (2007).
In determining whether a claimed invention would have been obvious a
court may ask whether the combination is nothing more than the predictable
use of prior art elements according to their established function. Id. The
obviousness analysis need not seek out precise teachings directed to the
specific subject matter of the challenged claim, for a court can take account
of the inferences and creative steps that a person of ordinary skill in the art
would employ. KSR, 127 S. Ct. at 1741.
The Examiner finds that though Stedman does not disclose
condensing and recirculating the steam that passes through the barrier 30
during open-cycle mode, Stedman does teach condensing and recirculating
the steam exiting the coolant channel 28 of the closed-cycle mode to recover
the coolant (Ans. 3). Based on this disclosure, the Examiner finds that the
teachings of the reference, as a whole, would have suggested condensing and
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recycling the steam produced during the open-cycle mode to recover the
diluent coolant (Ans. 3-4). We agree.
With regard to claim 12, Appellant’s primary argument is that
condensing and recycling coolant from the exhaust line following the
pressure relief means 36 would render Stedman’s dual mode fuel system
inoperable for its intended purpose. Specifically, Appellant contends that
Stedman’s open-cycle mode vents the diluent coolant such that adding a
radiator or condenser to the exhaust from the evaporative cooling line would
radically change the open cycle cooling mode of Stedman to a closed-cycle
cooling mode (Br. 16). We do not agree.
Rather, we find Stedman to disclose that it is known to use a radiator
and condenser to recover coolant from a cooling loop and that the open-
cycle venting is used where the heat removal by a radiator is not possible ,
such as where space for radiator cooling is limited. In our view such
disclosures indicate that it would have been obvious to combine a
radiator/condenser with the evaporative cooling open-mode cycle to collect
and reuse the coolant where the space or conditions permit. That Stedman
vents the coolant does not diminish the fact that Stedman evaporatively
cools regardless of the venting; venting is simply a way to dispose of the
coolant. In other words, combining a radiator/condenser with the
evaporative coolant exhaust line following valve 36 would not eliminate the
evaporative cooling. Rather, using a radiator/condenser would simply
permit the beneficial recovery of coolant as taught by Stedman.
We add that combining a radiator/condenser with Stedman’s open-
cycle mode would not completely form a closed-cycle as Appellant’s
contend. Stedman discloses that in the open-cycle mode electrolyte diluent,
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carried by a stream of recirculating reactant gas in which electrolyte diluent
is formed (i.e., loop 54), is vented overboard (i.e., the diluent is vented via
valve 84) (Stedman, col. 1, ll. 61-64; col. 3, ll. 65-75; col. 4, ll. 1-5).
Stedman further discloses that venting automatically occurs whenever
diluent must be removed at a rate higher than the rate the closed-cycle
electrolyte removal subsystem can handle (Stedman col. 1, ll. 64-67).
Stedman discloses using evaporative cooling and venting the stored diluent
(i.e., the diluent stored in liquid storage means 62) (Stedman, col. 1, ll. 67-
68).
These disclosures clearly indicate that the diluent is vented from two
locations in the open-cycle mode. First, the diluent is vented via valve 84.
Second, the recovered diluent stored in liquid storage means 62 is vented
after evaporation. Accordingly, placing a radiator/condenser in the
evaporative cooling exhaust line would not completely form a closed system
because the diluent may still be vented via valve 84. Accordingly,
Appellant’s argument that combining a radiator/condenser with the open-
cycle mode would render it inoperable for its intended purpose is not
persuasive.
Moreover, in light Stedman’s disclosures, we conclude that it would
have been obvious to combine a radiator/condenser with Stedman’s open-
cycle mode exhaust line following valve 36 because such is merely the
predictable use of a prior art element (i.e., a radiator/condenser) according to
its established function (i.e., condensing, cooling, and recovering coolant).
KSR, 127 S. Ct. at 1740. That Stedman does not explicitly state to add a
radiator/condenser to the open-cycle mode exhaust line is not dispositive
because Stedman discloses using a condenser/radiator for coolant recovery
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and we may take into account the inference and creative steps that one of
ordinary skill in the art would employ. KSR, 127 S. Ct. at 1741.
For the above reasons, we sustain the Examiner’s § 103 rejection of
claim 12 over Stedman.
With regard to claim 16, we agree with Appellant’s argument that
Stedman does not disclose drawing a vacuum in the second channels. The
Examiner’s only finding that Stedman discloses drawing a vacuum is based
upon the disclosure of a pressure relief means 36, which the Examiner
interprets as creating a vacuum in the steam channel (Ans. 3). However, the
Examiner has not provided any evidence to substantiate that a pressure relief
valve would create a vacuum (i.e., a sub-atmospheric pressure in the line as
exemplified by Appellant on page 9 of the Specification).
Rather, we agree with the statements provided in the Reynolds
Declaration that pressure relief valves do not create or draw a vacuum for
fluids upstream of the pressure relief valves (Reynolds Declaration ¶ 17).
The pressure upstream of the pressure relief valve is higher than the pressure
downstream of the pressure relief valve (Reynolds Declaration ¶ 17), and the
pressure relief valve opens when the pressure upstream reaches a value
greater than a preset pressure. Such evidence, in our view, refutes the
Examiner’s unsubstantiated finding that Stedman’s pressure relief means 36
draws a vacuum.
Accordingly, because the Examiner has not established that all the
claim features are taught or suggested by Stedman, we cannot sustain the
Examiner’s § 103 rejection of claims 16-21 over Stedman. In re Royka, 490
F.2d 981, 985 (CCPA 1974). For the same reasons, we cannot sustain the
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Examiner’s § 103 rejection of claims 13-15 over Stedman, which also recite
the vacuum feature.

DECISION
We do not sustain the Examiner’s § 103(a) rejection of claims 13-21
over Stedman.
We sustain the Examiner’s § 103 rejection of claim 12 over Stedman.
The 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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