Ex Parte Yu et al

Patent Trials and Appeals Board

May 8, 2019

14345058 - (D) (P.T.A.B. May. 8, 2019)

UNITED STA TES p A TENT AND TRADEMARK OFFICE
APPLICATION NO. FILING DATE
14/345,058 03/14/2014
13193 7590 05/10/2019
BLG(BL)
Borden Ladner Gervais LLP
1300-100 Queen Street
Ottawa, ON KIP IJ9
CANADA
FIRST NAMED INVENTOR
Xianguo Yu
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
ATTORNEY DOCKET NO. CONFIRMATION NO.
241373_7 5604
EXAMINER
ALI, WAQAAS A
ART UNIT PAPER NUMBER
1777
NOTIFICATION DATE DELIVERY MODE
05/10/2019 ELECTRONIC
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.
Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the
following e-mail address(es):
ipinfo@blg.com
Water1P.mail@ge.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE
THE PATENT TRIAL AND APPEAL BOARD
Ex parte XIANGUO YU, 1
Andrew Philip Shapiro, Rihua Xiong, Hai Yang, and Hui Liu
Appeal2018-004657
Application 14/345,058
Technology Center 1700
Before JEFFREY T. SMITH, BEYERL YA. FRANKLIN, and
MARK NAGUMO, Administrative Patent Judges.
NAGUMO, Administrative Patent Judge.
DECISION ON APPEAL
Xianguo Yu, Andrew Philip Shapiro, Rihua Xiong, Hai Yang, and
Hui Liu ("Yu") timely appeal under 35 U.S.C. § 134(a) from the Final
Rejection2 of claims 1-13 and 15-17. 3 We have jurisdiction. 35 U.S.C. § 6.
We reverse for reasons well-stated by Yu.
1 The real party in interest is identified as General Electric Company.
(Appeal Brief, filed 10 August 2017 ("Br."), 3.)
2 Office Action mailed 19 December 2016 ("Final Rejection"; cited as
"FR").
3 Remaining copending claims 18-20 have been withdrawn from
consideration by the Examiner (FR 1, § 5(a)), and are not before us.
Appeal2018-004657
Application 14/345,058
A. Introduction 4
OPINION
The subject matter on appeal relates to methods of improving the
performance of membranes used in membrane distillation.
The '058 Specification explains that, in membrane distillation, the
feed liquid, e.g., salt water, contacts a hydrophobic membrane having
through-pores. 5 (Spec. 1 [0002], [0005].) The surface tension of the water,
and the non-wetting hydrophobic character of the membrane, prevent the
liquid water from entering the pores. Given a sufficient temperature
difference across the membrane, water vapor, evaporated from the feed salt
water, may traverse the pores and condense on the other side, providing the
distillate, which is also referred to as the "permeate." (Id. at [0003].) The
relatively nonvolatile ions do not traverse the pores, so the permeate is
purified relative to the feed. In the words of the Specification, "[p]ores that
do become wetted will reduce the flux and selectivity of the membrane since
transport through the compromised pores will no longer be based on the
vapour pressure differential across the pore." (Id. at [0008].) Factors that
induce wetting are said to include adsorption of contaminants, and sufficient
pressure. (Id. at [0009].) The Specification teaches that "it is difficult to
manufacture a highly porous membrane with a pore size distribution that
4 Application 14/345,058, Performance of a membrane used in membrane
distillation, filed 14 March 2014 as the national stage under 35 U.S.C. § 371
of PCT/CN2011/001569, filed 16 September 2011. We refer to the
'"058 Specification," which we cite as "Spec."
5 If the feed liquid is hydrophobic, the porous membrane must be
hydrophilic. (Spec. 1 [0002].)
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Application 14/345,058
does not include some individual pores which are large enough to wet under
some conditions." (Id. at 2-3 [0010].) Thus, the pores may trap liquids (or
solid particles) at any time during manufacture, use, or storage.
(Id. at3 [0011].)
Yu seeks patent protection for a method of opening pores closed by
wetting and trapping of liquids, in which gas is applied to one side of a
membrane at a pressure higher than the gas or liquid on the other side of the
membrane, at a sufficient pressure differential to push the trapped liquid out
of the pores. (Id. at 4 [0022].)
Claim 1 is representative and reads:
A method comprising:
purifying a feed liquid using a membrane in a membrane
distillation process; and
applying a sufficient pressure to the membrane
to generate a sufficient pressure difference across the
membrane to open pores that are
semi-closed due to liquid trapped in the pores,
pores that are closed due to liquid trapped in the pores, or
both semi-closed and closed pores that are semi-closed
and closed due to liquid trapped in the pores,
in the membrane before, after, or both before and after,
the membrane is used to purify the feed liquid.
(Claims App., Br. 26; some formatting, and emphasis added.)
Remaining independent claim 6 is similar, reciting only the process of
treating the membrane, 6 but further requiring one of three ways the pressure
6 The preamble recites that the membrane is "for use in a membrane
distillation process." It does not appear to be disputed on the present record
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Application 14/345,058
difference across the membrane is generated by gases on both sides of the
membrane.
The Examiner maintains the following grounds of rejection: 7, 8
A. Claims 1---6, 8-13 and 15-17 stand rejected under 35 U.S.C.
§ I02(b) or under§ I03(a) in view ofFane. 9
Al. Claim 7 stands rejected under 35 U.S.C. § 103 in view of the
combined teachings of Fane and Zha. 10
B. Claims 1-13 and 15-17 stand rejected under 35 U.S.C.
§ I03(a) in view of the combined teachings ofMa 11 and
Kopp.12
that this recitation imposes limitations on the properties of the membrane, as
discussed supra in the introduction.
7 Examiner's Answer mailed 25 January 2018 ("Ans.").
8 Because this application claims the benefit of priority to an application
filed before 16 March 2013, the effective date of the America Invents Act,
we refer to the pre-AIA version of the statute.
9 Anthony G. Fane et al., Contaminated inflow treatment with membrane
distillation bioreactor, U.S. Patent Application Publication
2010/0072130 Al (25 March 2010) (cited as an equivalent ofEP 1 909 948
(2008), although both documents are available under§ I02(b)).
1° Fugan Zha et al., Methods of cleaning membrane modules, U.S. Patent
Application Publication 2006/0261007 Al (2006).
11 Zidu Ma et al., High-temperature membrane distillation, U.S. Patent
Application Publication 2009/0152199 Al (2009).
12 Virgil Kopp et al., Concentration of solids in a suspension using hollow
fibre membranes, WO 93/02779 (1993).
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Application 14/345,058
B. Discussion
The Board's findings of fact throughout this Opinion are supported by
a preponderance of the evidence of record.
Rejections A and Al: Fane
Yu urges that the Examiner erred harmfully in finding that pores,
closed due to liquid trapped in the pores in the membrane of the distillation
bioreactor disclosed by Fane, would be opened by supplying aeration to the
mixed liquor for fouling control. In particular, the Examiner finds that "[i]t
is inherent that injecting air across membrane would obviously produce a
pressure difference to remove the foulants embedded on the membrane and
open both semi-closed and closed pores on the membrane." (FR 4, 11. 4--7.)
In Yu's view, however, the Examiner has not come forward with
evidence that the turbulence and shear stress induced by the injected air
"creates a pressure difference across the membrane that is sufficient to open
pores that are closed or semi-closed due to liquid in the pores." (Br. 13,
11. 4--6.) Yu points out that Fane seeks to remove solid floes from the
surface of the membranes, and argues that "the Examiner has not provided
any evidence that air sparging would open a pore filled with water, and has
not provided any explanation or rationale for why a skilled person would
have [had] any expectation that air sparging would open pores that are
closed or semiclosed due to liquid trapped in the pores." (Id. at 11. 12-16.)
The Examiner responds that "if a pressure difference is able to displace
liquid and solid in case of the instant application, then it should also be
capable of removing solids and liquids in any situation where a pressure
difference is applied on a membrane." (Ans., sentence bridging 11-12.)
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Application 14/345,058
The Federal Circuit has explained that, "elements found to be present
inherently must necessarily be present in or result from the prior art." In re
Montgomery, 677 F.3d 1375, 1379-80 (Fed. Cir. 2012).
"Inherency ... ," the court continued, "may not be established by
probabilities or possibilities." Id. at 1380.
The flaws in the Examiner's reasoning arise from failing to account
for the differences between what is disclosed in the prior art-here, directing
a stream of air bubbles in water towards the surface of the membrane to
remove floes of solids deposited on the surface of the membrane-and what
is required by the claims, namely, applying a pressure differential across the
membrane sufficient to displace liquid trapped in pores of the membrane.
The Examiner concludes that the aeration that displaces solids will
"obviously" create a pressure differential that displaces liquid trapped in the
pores, but offers no evidence or explanation why this would be expected to
be so. But the Specification indicates that an iterative process can be useful
for choosing an effective pressure difference, wherein it may be necessary to
"treat[] the membrane to a second pressure difference which is greater than
the first pressure difference if the measured characteristics did not meet a
desired threshold". (Spec. 6 [0030], third bullet (emphasis added).) Thus,
the opening of the pore is not necessarily the natural or inevitable result of
applying a pressure differential across the membrane. Rather, the pressure
difference must be of at least a minimum magnitude.
Moreover, as Yu points out, discussing the behavior of air bubbles in
a liquid in the context of the three ways recited in claim 6 of generating the
pressure difference across the membrane, "[b ]ubbles and liquid directly
surrounding such bubbles are in pressurized equilibrium." (Br., para.
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bridging 14--15.) As a bubble rises through the liquid, the pressure
decreases, and the volume of the bubble increases----equivalently, if there is
extra pressure in the bubble, the volume increases. (Id.) Thus, as Yu argues,
"a bubble in Pane's chamber that touches the membrane would not be a
'pressurized gas' or a 'gas at a reduced pressure."' Rather, it would have the
same pressure as the surrounding liquid. The Examiner does not point out,
nor do we perceive any error in this analysis, which relies solely on
elementary physical considerations. In any event, the Examiner has not
explained why the pressure provided by or associated with the bubbles of
gas in the liquid would have been expected to be enough to displace liquid
trapped in the pores.
The Examiner makes no findings regarding Zha that cure the
deficiencies of Fane.
We therefore reverse Rejections A and Al.
Rejection B: Ma and Kopp
Yu urges the Examiner erred in concluding that the ordinary worker
would have combined the teachings of Ma and Kopp with a reasonable
expectation of arriving at a cleaning process for membrane-distillation
membranes as claimed. (Br. 18.) First, in Yu's view, there is no evidence
that Ma teaches or suggests a problem with pores being closed due to
trapped liquid. Rather, Yu argues, based on Ma, conventional cleaning
methods, such as chemical cleaning to remove scale, or air sparging ( such as
used by Fane) would have been considered. (Id. at 21, 1st para.) Second,
Yu argues that Ma and Kopp are directed to fundamentally different systems
and processes, namely, membrane distillation and microfiltration,
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Application 14/345,058
respectively. (Id. at 2d para.) More particularly, Yu urges, Ma is directed
towards a feed solution being provided at a constant elevated temperature
and pressure, with no suggestion that the periodic draining and back flushing
to displace filtered particles as taught by Kopp might be useful. (Id. at last
para.) Moreover, Yu argues, where Ma requires that the membrane not be
wetted by the liquid to be membrane-distilled, Kopp requires that the
membrane be wetted to perform filtration, and teaches expressly that failure
to wet the membrane results in unacceptably low filtration flow. (Id. at 22,
1st para.; see Kopp at 28, 1. 9, to 29.)
The Examiner responds that the generally known occurrence of
clogging or fouling would have prompted consideration of any method of
cleaning filters, including the back-flushing methods taught by Kopp.
(Ans. 15-16, citing, apparently for the first time, 13 additional references.)
As for the fundamentally different processes and the requirement by Kopp
that the filter be wetted by the filtrate, the Examiner finds that "the
membranes of Ma and Kopp are substantially the same (including the type
of membrane, the material of the membrane and the pore size of the
membrane)" (id. at 17, 11. 15-16) and would have prompted using Kopp's
cleaning methods "to enhance filter longevity and filtration efficiency"
(id. at 1. 18-19) with a reasonable expectation of success (id. at 1. 20). The
Examiner finds further that Kopp teaches the rewetting is optional (id. at 18,
citing Kopp 4, 11. 10-12, emphasizing the word "may") and reasoning that
examples and preferred embodiments are not teachings away from a broader
13 Reply Brief, filed 26 March 2018 ("Reply") 11, 11. 12-13, stating that two
references are "newly applied."
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Application 14/345,058
disclosure. The continuous nature of Ma's process would not have been a
problem, according to the Examiner, because Kopp teaches that the cleaning
occurs after "terminating the filtration." ( Ans. 19.)
The weight of the evidence favors Yu. The problem addressed by
Kopp arises in the context of "concentrating solids is a suspension using a
hollow filter membrane." (Kopp 1, 11. 4--5.) Other than a generalized
concern for fouling, the Examiner has not directed our attention to any
disclosure in Ma that would have indicated that a problem similar to that
solved by Kopp exists for the membrane distillation membrane ("MD
membrane") disclosed by Ma. The additional references cited (improperly)
by the Examiner appear to be no more than cumulative with Ma and Fane,
and offer similar measures to address fouling of the MD membrane,
including the provision of other filters (cf Ma 1 [0011], last sentence,
"Distillation system 10 also desirably includes standard fluid processing
equipment (not shown), such as process control units, fluid pumps,filters,
and discharge lines" ( emphasis added)). Nor has the Examiner directed our
attention to any disclosure suggesting that Ma regarded pore closing due to
trapped liquid to be a problem.
It is generally not obvious to solve a problem that is not recognized.
While the incidental solution of an unrecognized problem while solving a
known problem may support a conclusion of prima facie obviousness, the
Examiner has not identified a known problem in the present record relating
to the high temperature membrane distillation process described by Ma that
would have prompted the ordinary worker to consider and apply the
teachings of Kopp. The only source of such a teaching is Yu's
'058 Specification. But hindsight is not a proper basis for obviousness.
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We therefore reverse the rejection based on Ma and Kopp.
C. Order
It is ORDERED that the rejections of claims 1-13 and 15-17 are
reversed.
REVERSED
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