Ex Parte Barleben et al

Patent Trials and Appeals Board

Nov 20, 2014

11791349 - (D) (P.T.A.B. Nov. 20, 2014)

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.
11/791,349 05/22/2007 Roger-Marcelo Barleben 510.1170 1518
23280 7590 11/21/2014
Davidson, Davidson & Kappel, LLC
485 7th Avenue
14th Floor
New York, NY 10018
EXAMINER
O DONNELL, LUCAS J
ART UNIT PAPER NUMBER
1726
MAIL DATE DELIVERY MODE
11/21/2014 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 PATENT TRIAL AND APPEAL BOARD
____________

Ex parte ROGER-MARCELO BARLEBEN, UWE LIMBECK,
COSIMO MAZZOTTA, HANS-JOERG PFLUGFELDER,
and MANFRED STROHMAIER1
____________

Appeal 2013-003119
Application 11/791,349
Technology Center 1700
____________

Before TERRY J. OWENS, BEVERLY A. FRANKLIN, and
JEFFREY W. ABRAHAM, Administrative Patent Judges.

ABRAHAM, Administrative Patent Judge.

DECISION ON APPEAL
This is a decision on an appeal under 35 U.S.C. § 134 from the
decision of the Primary Examiner rejecting claims 18–20, 23–30, 32–34, and
37–41.2 We have jurisdiction pursuant to 35 U.S.C. § 6(b). We affirm-in-
part.

1 According to the Appeal Brief, the Real Party in Interest is Daimler AG.
App. Br. 2.
2 The Examiner also rejected claim 36, which Appellants subsequently
cancelled.
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BACKGROUND
Appellants’ claimed invention is directed to fuel cell systems having a
simplified overall structure while maintaining the ability to separate and
carry away liquid water from the system. Spec. ¶ 17. The claimed methods
and systems include liquid separators and corresponding liquid outputs and
output/bypass lines placed at specific locations and arranged in specific
configurations within fuel cells in order to reduce the number of individual
components as compared to systems known in the prior art. See id. at ¶¶ 17–
22.
Independent claims 18, 37, and 38 are illustrative (key limitations in
dispute italicized), and are reproduced below:
18. A fuel cell system comprising:
at least one fuel cell having an anode area and a
cathode area separated from the anode area by an
electrolyte, the cathode area having a cathode gas output
line;
a first liquid separator having a first liquid outlet;
a second liquid separator having a reservoir and a
level sensor for measurement of a liquid level in the
reservoir, the second liquid separator having a second
liquid outlet connected to a liquid output line, the second
liquid separator having a valve arranged in the liquid
output line, the valve opening the liquid output line when
the liquid level in the reservoir has reached a
predetermined height;
a first bypass line extending from the liquid outlet
of the first liquid separator to the second liquid separator
or to the cathode gas output line;
and an orifice plate in the first bypass line,
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the first bypass line being heated by at least one of
an electrical heater and operational heat to ensure melting
of any frozen fluid in the first bypass line,
the first liquid separator not including a level
sensor for measurement of the liquid level in the first
liquid separator or a valve for emptying the liquid out of
the first liquid separator in a controlled manner such that
the liquid separated out by the first liquid separator is
carried away from the first liquid separator to the second
liquid separator continuously via the first bypass line.
37. A fuel cell system comprising:
at least one fuel cell having an anode area and a
cathode area separated from the anode area by an
electrolyte;
a first liquid separator having a first liquid outlet;
a second liquid separator having a second liquid
outlet, the first liquid outlet being connected via a first
bypass line to the second liquid separator or to a cathode
gas output line,
the first bypass line capable of being heated by at
least one of operational heat and an electrical heater to
ensure melting of any frozen fluid in the first bypass line;
an orifice plate in the first bypass line for limiting
the volume flow from the first liquid separator through
the first bypass line;
a third liquid separator removing liquid from
cathode gas entering into the cathode area, the second
liquid outlet being coupled to the third liquid separator
such that liquid exiting the second liquid outlet enters
into the third liquid separator.
38. A method for operating a fuel cell system including
at least one fuel cell having an anode area and a cathode
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area separated from the anode area by an electrolyte, and
a first liquid separator having a liquid outlet, the liquid
outlet being connected via a first bypass line to a second
liquid separator or to a cathode gas output line, the
method comprising:
heating the first bypass line via at least one of
operational heat and an electrical heater to remove any
frozen liquid in the first bypass line; and
providing an orifice plate in the first bypass line to
ensure that leakage of gases from the first liquid
separator to the second liquid separator is kept as small
as possible.
The Examiner maintains, and Appellants appeal, the following
grounds of rejection:
1. Claims 18–20, 29, 32–34, and 38 as unpatentable under 35 U.S.C.
§ 103(a) over Walsh (US 2003/0044670 A1, published Mar. 6,
2003) in view of Sakai (US 2006/0035120 A1, published Feb. 16,
2006) and Walsh (US 6,743,540 B2, issued June 1, 2004) (“Walsh
’540”), as evidenced by Turco (US 2005/0142400 A1, published
June 30, 2005).
2. Claims 23–25, 28,3 30, and 37 as unpatentable under 35 U.S.C. §
103(a) over Walsh in view of Sakai, and further in view of Walsh
’540.

3 In the Answer, the Examiner withdrew the rejection stated in the January 9,
2012 Non-Final Action (Ans. 16), and provided New Grounds of Rejection
for claim 28 (id. at 12–14). This listing reflects the art cited in the New
Grounds of Rejection.
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3. Claims 26, 27, 37, and 40 as unpatentable under 35 U.S.C. §
103(a) over Walsh in view of Sakai, and further in view of Walsh
’540 and Nonobe (US 2002/0094467 A1, published July 18, 2002).
4. Claims 39 and 414 as unpatentable under 35 U.S.C. § 103(a) over
Walsh in view of Sakai, and further in view of Nonobe, Walsh
’540, and Gopal (US 2007/0065711 A1, published Mar. 22, 2007).

OPINION

Claim 38
Claim 38 requires “providing an orifice plate in the first bypass line to
ensure that leakage of gases from the first liquid separator to the second
liquid separator is kept as small as possible.”
The Examiner finds that Walsh discloses a fuel cell system with a first
liquid separator (108), connected by a first bypass line (114) to a second
liquid separator (112), which is connected to a water tank (118). Ans. 3.
Although the Examiner acknowledges that Walsh does not expressly
disclose an orifice plate in drain line 114,5 the Examiner finds that Walsh

4 In the Answer, the Examiner withdrew the rejection stated in the January 9,
2012 Non-Final Action (Ans. 16), and provided New Grounds of Rejection
for claims 39 and 41 (id. at 14–15). This listing reflects the art cited in the
New Grounds of Rejection.
5 The Examiner admits that there was an error in the Non-Final Action with
regard to the “orifice” limitation, but maintains that the limitation is
rendered obvious by the cited prior art references. See Ans. 18–20, 22–24.
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discloses placing gas flow limiting orifices on other drain lines (104 and
106) to restrict gas flow, and further finds that Walsh generally teaches that
it is desirable to prevent gas from flowing through water trap 108, drain line
114, and water trap 112 and entering water tank 118. Id. at 7 (citing Walsh
¶¶ 19 and 33). The Examiner concludes that it would have been obvious to
one of skill in the art, based on the disclosure in Walsh, to include a gas flow
limiting orifice on drain line 114 as additional protection against gas
traveling through the water traps and into the water tank. Id. at 8.
Appellants argue that Walsh only teaches that the use of gas flow
limiting devices is advantageous on certain drain lines having high pressures
and high flow rates. Reply Br. 2. Appellants contend that drain line 114 is
not subjected to high pressure or a high flow rate, and therefore the
Examiner’s reasoning “lacks a requisite rational underpinning and is a result
of improper hindsight bias.” Id.
We are not persuaded by Appellants’ arguments. It is uncontested
that Walsh discloses the use of gas limiting flow devices (i.e., orifice plates)
on certain drain lines to restrict the flow of gas to certain locations in the fuel
cell system. See, e.g., Walsh ¶ 19. It is also uncontested that, even with
these limiting devices in drain lines 104 and 106, it is possible for high
pressure combustible gas to pass through both water traps (108 and 112) and
into the water tank (118). Id. at ¶ 33. Because Walsh seeks to minimize the
amount of “potentially explosive gas mixtures” in water tank 118, we find
the Examiner reasonably concluded that it would have been obvious to a
person of ordinary skill in the art to include a gas flow limiting orifice on
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drain line 114 to help further reduce the potential for gas to accumulate in
water tank 118. Ans. 8. Contrary to Appellants’ argument, Walsh does not
limit the placement of gas flow limiting orifices to drain lines that are
subject to high pressures or flow rates. The portion of Walsh to which
Appellants cite in support of their argument is expressly described as an
example. See, e.g., Walsh ¶19.
For the foregoing reasons, we sustain the Examiner’s rejection of
independent claim 38.

Claim 18
Appellants’ challenge the Examiner’s finding that the combination of
Walsh and Walsh ’540 discloses or renders obvious the “second liquid
separator” required in claim 18. According to Appellants, the Examiner
erred by finding that water trap 112 and water tank 118 of Walsh correspond
to the claimed “second liquid separator.” App. Br. 8. Appellants contend
that water tank 118 “cannot reasonably [be] considered to be part of a
‘liquid separator’ because water tank 118 does not separate liquid from
gas.” Id. at 8–9. Appellants further argue that water tank 118 is a
completely distinct structure from water trap 112, and is solely used to store
water that is already separated from gas when it is in the tank. Id. at 9;
Reply Br. 2. Additionally, Appellants argue that tank 118 cannot be the
“second liquid separator” because it does not have a liquid outlet connected
to a liquid output line, as required in claim 18. Reply Br. 2.
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The Examiner finds that Walsh water tank 118 “is a liquid separator
because gas in the tank is purged and therefore separated from the liquid in
the tank.” Ans. 17.
The preponderance of evidence supports Appellants’ position.
According to Walsh, the water from trap 112 (which is separated from gas)
is collected in a separate water tank 118. E.g., Walsh ¶ 36. Therefore, we
agree with Appellants that water tank 118 merely stores water that has
already been separated from gas. See Reply Br. 2. Moreover, the Examiner
has not directed us to any persuasive factual evidence demonstrating that a
person of ordinary skill in the art would consider a structure identified as a
water tank to be a “liquid separator” because gas is purged from that tank,
especially when the cited prior art references expressly identify other
structures as liquid separators (e.g., water traps 108 and 112).
Because we find that the Examiner has failed to demonstrate that the
cited prior art references disclose or would have rendered obvious the
claimed “second liquid separator,” we reverse the Examiner’s rejection of
independent claim 18. We also reverse the Examiner’s rejection of
dependent claims 19, 20, and 23–34, which depend from claim 18, for the
same reason.

Claim 37
Claim 37 requires “a third liquid separator removing liquid from
cathode gas entering into the cathode area, the second liquid outlet being
coupled to the third liquid separator such that liquid exiting the second liquid
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outlet enters into the third liquid separator.” The Examiner acknowledges
that Walsh does not disclose this requirement, but finds that Walsh ’540
discloses a system with four liquid separators, one of which removes liquid
from a cathode feed line. Ans. 10–11. The Examiner identifies the four
separators as elements 348, 354, and 302 (water tank) in Figure 3 of Walsh
’540, along with “a drain with a gas flow limiting device” on the cathode
feed line. Id. at 11. According to the Examiner, separators 348, 354, and the
“drain with a gas flow limiting device” all drain into water tank 302,
satisfying the limitation that the second liquid outlet drains into the third
liquid separator. Id. at 11 and 26. The Examiner concludes that it would
have been obvious to a person of ordinary skill in the art to modify Walsh by
adding a separator to the cathode feed line, as disclosed by Walsh ’540, in
order to separate liquids from additional process streams, and that the
additional separator would be connected to other separators by additional
bypass lines, in view of drain line 114 in Walsh. Id. at 11–12.
Appellants argue that only elements 348 and 354 in Walsh ’540 are
“liquid separators.” App. Br. 12. Appellants again argue that gas is already
separated from liquid in water tank 302, and therefore it is not a “liquid
separator” as claimed. Reply Br. 5. Appellants therefore contend that a
person of ordinary skill in the art would not have been motivated to modify
Walsh by adding separators in view of Walsh ’540, and that Walsh and
Walsh ’540 do not teach or suggest configuring a third liquid separator to the
cathode feed line such that liquid exiting out of second water trap 112 of
Walsh enters into the third liquid separator. Id.
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The preponderance of evidence again supports Appellants’ position.
The Examiner’s rejection is premised on the finding that water tank 302 is
the “third liquid separator” required in claim 37. For the same reasons stated
above with regard to claim 18, we agree with Appellants that water tank 302
is not a “liquid separator” as claimed. Therefore, the Examiner erred in
concluding that Walsh ’540 discloses or suggests a third liquid separator
removing liquid from cathode gas entering into the cathode area and
arranged such that the outlet of the second liquid separator drains into the
third liquid separator.
Because we find that the Examiner has failed to demonstrate that the
cited prior art references disclose or would have rendered obvious the
claimed “third liquid separator,” we reverse the Examiner’s rejection of
independent claim 37. We also reverse the Examiner’s rejection of
dependent claims 39–41, which depend from claim 37, for the same reason.

CONCLUSION
For the reasons set forth above, we affirm the Examiner’s final
rejection of claim 38 under 35 U.S.C. § 103, and reverse the final rejection
of claims 18–20, 23–30, 32–34, 37, and 39–41.
No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a).
AFFIRMED-IN-PART

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