Ex Parte Prosser et al

Patent Trial and Appeal Board

Feb 25, 2015

11818636 (P.T.A.B. Feb. 25, 2015)

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.
11/818,636 06/15/2007 Neil Mark Prosser 21719 1293
27182 7590 02/26/2015
PRAXAIR, INC.
LAW DEPARTMENT - M1-04
39 OLD RIDGEBURY ROAD
DANBURY, CT 06810-5113
EXAMINER
LANDEROS, IGNACIO EMMANUEL
ART UNIT PAPER NUMBER
3744
MAIL DATE DELIVERY MODE
02/26/2015 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 NEIL MARK PROSSER and RICHARD JOHN JIBB
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Appeal 2013-001003
Application 11/818,636
1

Technology Center 3700
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Before STEFAN STAICOVICI, ANNETTE R. REIMERS, and
ERIC C. JESCHKE, Administrative Patent Judges.

STAICOVICI, Administrative Patent Judge.

DECISION ON APPEAL

STATEMENT OF THE CASE
Neil Mark Prosser and Richard John Jibb (Appellants) appeal under
35 U.S.C. § 134 from the Examiner’s decision finally rejecting claims 1–14.
We have jurisdiction over this appeal under 35 U.S.C. § 6(b).

SUMMARY OF DECISION
We REVERSE.

INVENTION

1
According to Appellants, the real party in interest is Praxair
Technology, Inc. Br. 1.
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Application 11/818,636
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Appellants’ invention relates to a device and method “for separating
air into nitrogen and oxygen-rich products by cryogenic distillation.” Spec.
¶ 1 and Fig. 1.
Claims 1 and 8 are independent. Claim 1 is illustrative of the claimed
invention and reads as follows:
1. A method of separating air comprising:
producing a first compressed and purified air stream and
a second compressed and purified air stream having a higher
pressure than the first compressed and purified air stream;
cooling the first compressed and purified air stream and
the second compressed and purified air stream in a lower
pressure heat exchanger and a higher pressure heat exchanger,
respectively, through indirect heat exchange with return streams
generated in an air separation unit, thereby to produce a main
feed air stream and a high pressure air stream, either in a liquid
or dense phase fluid state;
introducing the main feed air stream into a higher
pressure column of the air separation unit, expanding the high
pressure air stream and introducing at least part of the high
pressure air stream into at least one of a lower pressure column
and a high pressure column of the air separation unit;
the return streams comprising at least part of a pumped
liquid oxygen stream composed of a liquid oxygen column
bottoms of the lower pressure column that is introduced into the
higher pressure heat exchanger and vaporized and first and
second subsidiary waste nitrogen streams, formed from a waste
nitrogen stream removed from the lower pressure column, that
are introduced into the higher pressure heat exchanger and the
lower pressure heat exchanger, respectively, for thermal
balance purposes; and
the higher and lower pressure heat exchangers being
configured such that that first subsidiary waste nitrogen stream
undergoes a higher pressure drop in the higher pressure heat
exchanger than the second subsidiary waste nitrogen stream
undergoes in the lower pressure heat exchanger by passing the
first subsidiary waste nitrogen stream through a cross-sectional
Appeal 2013-001003
Application 11/818,636
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flow area within the higher pressure heat exchanger that is sized
to produce the higher pressure drop.

REJECTIONS
The following rejections are before us for review:
I. The Examiner rejected claims 1 and 8 under 35 U.S.C. § 103(a)
as unpatentable over Agrawal (US 5,355,682, issued Oct. 18,
1994), Mehta (US 5,711,166, issued Jan. 27, 1998), and Mesher
(US 3,661,203, issued May 9, 1972).
II. The Examiner rejected claims 2 and 9 under 35 U.S.C. § 103(a)
as unpatentable over Agrawal, Mehta, Mesher, and Dunn (US
5,106,398, issued Apr. 21, 1992).
III. The Examiner rejected claims 3, 4, 10, and 11 under 35 U.S.C.
§ 103(a) as unpatentable over Agrawal, Mehta, Mesher, Dunn,
and Prosser (US 6,626,008 B1, issued Sept. 30, 2003).
IV. The Examiner rejected claims 5 and 12 under 35 U.S.C.
§ 103(a) as unpatentable over Agrawal, Mehta, Mesher, Dunn,
Prosser, and Appellants’ Admitted Prior Art (Spec. ¶ 6)
(hereafter “AAPA”).
V. The Examiner rejected claims 6, 7, 13, and 14 under 35 U.S.C.
§ 103(a) as unpatentable over Agrawal, Mehta, Mesher, Dunn,
Prosser, and Lehman (US 6,321,568 B1, issued Nov. 27, 2001).

ANALYSIS
Rejection I
Appellants do not present arguments for the patentability of claim 8
apart from claim 1. See Br. 13–15. Therefore, in accordance with
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37 C.F.R.§ 41.37(c)(1)(vii)(2011), we select claim 1 as the representative
claim to decide the appeal of the rejection of these claims, with claim 8
standing or falling with claim 1.
The Examiner finds that the combined teachings of Agrawal and
Mehta disclose the limitations of independent claim 1, but fail to disclose
configuring a cross-sectional flow area in the higher pressure heat exchanger
so as to obtain a higher pressure drop of a first subsidiary waste nitrogen
stream in the higher pressure heat exchanger as compared to the pressure
drop of a second subsidiary waste nitrogen stream flowing through the lower
pressure heat exchanger. See Ans. 5–7. Nonetheless, the Examiner finds
that Mesher discloses “that it is well known to configure a heat exchanger
such that a cross sectional flow area may be varied.” Id. at 7 (citing Mesher,
col. 2, ll. 20–30, 35–39, and 46–55). The Examiner then concludes that it
would have been obvious for a person of ordinary skill in the art
to provide a smaller cross-sectional flow area, as
taught by Mesher, for the first waste nitrogen
stream in the high pressure heat exchanger of
Agrawal, as modified [by Mehta], in order to
advantageously improve the performance and heat
transfer efficiency of the heat exchanger and
improve system versatility by allowing for
adjustable flow area depending on the fluid and
state thereof.
Id.
Appellants argue that because Mesher discloses varying plate spacing
in a heat exchanger to accommodate fluids having dissimilar properties and
because Agrawal’s nitrogen streams 304, 310 flow from the same nitrogen
stream 30, “it is difficult to understand why anyone skilled in the art would
be motivated by Mes[h]er to modify Agrawal and only vary the plate
spacing in the high pressure heat exchanger 2 and not the low pressure heat
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exchanger 1 to produce equal pressure drops in the nitrogen streams being
introduced into such heat exchangers.” Br. 14–15. Thus, according to
Appellants, “the Examiner’s assertion of obvious[ness] is merely an
improper hindsight rejection.” Id. at 15.
At the outset, we note that Appellants discuss streams 304, 310 of
Agrawal as the claimed “first and second subsidiary waste nitrogen
streams.” See e.g., Br. 14. However, the Examiner relies on Agrawal’s
nitrogen streams 400, 800 as the “first and second subsidiary waste nitrogen
streams.” See Ans. 6, 16; see also Agrawal, Fig. 2. That being said, we
nonetheless find Appellants’ arguments persuasive because although Mesher
discloses that it is well known to vary the cross-sectional flow area of a heat
exchanger, the Examiner’s rejection is insufficient to explain what would
have prompted a person having ordinary skill in the art to apply Mesher’s
technique of varying the cross-sectional flow area specifically to the higher
pressure heat exchanger 2 of Agrawal, as modified by Mehta.
Without articulated reasoning based on rational underpinning for
modifying the reference as proposed, the Examiner’s rejection appears to be
the result of hindsight analysis. See In re Kahn, 441 F.3d 977, 988 (Fed.
Cir. 2006) (cited with approval in KSR Int’l Co. v. Teleflex Inc., 550 U.S.
398, 418 (2007)). In this case, the Examiner has not provided any findings
that providing a higher pressure drop in nitrogen stream 400 as it flows
through higher pressure heat exchanger 2 of Agrawal, as modified by Mehta
and Mesher, would “improve the performance and heat transfer efficiency of
the heat exchanger and improve system versatility by allowing for adjustable
flow area depending on the fluid and state thereof.” See Ans. 6–7 and 16–
17. More specifically, the Examiner has not provided reasoning based on
rational underpinning showing how a greater pressure drop in the nitrogen
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stream flowing through the higher pressure heat exchanger “improve[s] the
performance and heat transfer efficiency of the heat exchanger and
improve[s] system versatility.” Actually, the Examiner’s modification to
provide a greater pressure drop in Agrawal’s nitrogen stream 400 as it passes
through higher pressure heat exchanger 2 appears to reduce the efficiency of
the heat exchanger because Agrawal specifically discloses pressurizing
nitrogen stream 400 prior to its flowing through higher pressure heat
exchanger 2 in order to obtain a high pressure nitrogen gas stream having a
pressure of 1,135 psi. See Agrawal, col. 2, l. 63 through col. 3, l. 2 and the
Table (compare with nitrogen stream 800’s pressure of 85.5 psi).
As such, absent hindsight, we fail to see why a person having ordinary
skill in the art would have modified the process and system of Agrawal in
the manner claimed. Therefore, we do not sustain the rejection of claim 1,
and claim 8 falling with claim 1, under 35 U.S.C. § 103(a) as unpatentable
over Agrawal, Mehta, and Mesher.

Rejections II–V
Rejections II–V are based on the same insufficient articulation of a
reason to combine Agrawal, Mehta, and Mesher, as described supra. The
Examiner’s use of the teachings of Dunn, Prosser, AAPA, and Lehman does
not remedy the deficiencies of Agrawal, Mehta, and Mesher, as described
above. See Ans. 7–15. Therefore, for the reasons set forth above, we
likewise do not sustain these rejections.
SUMMARY
We REVERSE the Examiner’s decision to reject claims 1–14.
REVERSED
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