Ex Parte Cote et al

Board of Patent Appeals and Interferences

Dec 12, 2008

09916247 (B.P.A.I. Dec. 12, 2008)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte PIERRE COTE, HAMID RABIE,
NICHOLAS ADAMS, HIDAYAT HUSAIN,
HENRY BEHMANN, STEVEN PEDERSEN, and
JASON CADERA
____________

Appeal 2008-3026
Application 09/916,247
Technology Center 1700
____________

Decided: December 12, 2008
____________

Before BRADLEY R. GARRIS, CHUNG K. PAK, and
JEFFREY T. SMITH, Administrative Patent Judges.

SMITH, Administrative Patent Judge.

DECISION ON APPEAL
This appeal involves claims 26-36, the only claims pending in this
application. We have jurisdiction under 35 U.S.C.
§ 134.
We AFFIRM
Appeal 2008-3026
Application 09/916,247

Appellants’ invention is directed to a process for filtering water
containing solids with membranes in a tank. The claimed process includes
the backwashing with a chemical cleaner of one or more suction driven
ultrafiltration or microfiltration membranes normally immersed in water
containing solids that become dirty or fouled during normal operation.
Representative independent claim 26, as presented in the Brief, appears
below:
26. A process for filtering water containing solids with membranes
in a tank comprising the steps of:

a) filling the tank with a feed water to be filtered to
immerse the membranes;

b) creating a transmembrane pressure between a
permeate side and a retentate side of the membranes, the retentate side
of the membranes being in contact with the water in the tank at
ambient pressure, the permeate side being subject to a negative
pressure relative to the pressure of the water in the tank fluidly
connected to a filtered permeate outlet, to generate a filtered permeate
at the permeate outlet and a retentate in the tank;

c) aerating the membranes to dislodge solids from
the membranes;

d) backwashing the membranes; and,

e) draining the tank of the retentate;

wherein

i) the steps above are performed
in repeated cycles; and,

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ii) the steps of backwashing the
membranes and draining the tank in a
cycle may be performed either before
the other or partially or substantially
simultaneously; and,

f) wetting the membranes at least once per week
with a cleaning chemical having a selected concentration for a
selected duration after performing step (b) in a first cycle and after or
while performing step (e) in the first cycle, without returning to step
(b) in the first cycle and before starting a subsequent cycle.

The Examiner relies on the following references in rejecting the
appealed subject matter:
Smith US 5,403,479 Apr. 4, 1995
Del Vecchio US 6,331,251 B1 Dec. 18, 2001
Appellants appeal the rejections as follows: 1
The Examiner rejected claims 26-36 under 35 U.S.C. § 103 as obvious
over Smith and Del Vecchio. 2
The Examiner rejected claims 26-28, 31, and 34-36 under 35 U.S.C. §
103 as obvious over Del Vecchio.

1 The Examiner has withdrawn the statutory double patenting rejection of
claims 26-29, 31, and 33 and the obviousness type double patenting rejection
of claims 26-36 (Ans. 4).
2 The Examiner under a separate heading indicated that claims 29, 30, 32,
and 33 were rejected over the combination of over Del Vecchio and Smith.
Our response to this rejection has been incorporated into the discussion
presented for this rejection because the combination of references is the
same. All of Appellants’ arguments in rebuttal to both rejections have been
considered.
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Application 09/916,247

ISSUE
The Examiner finds that Smith and Del Vecchio describe methods for
cleaning one or more membranes normally immersed in water containing
solids in a tank that includes draining the tank during the cleaning process.
(Ans. 5-10). The Examiner recognizes that Smith discloses the use of
cleaning agents of varying concentrations for cleaning the membranes.
(Ans. 5). The Examiner recognizes that Smith discloses that draining the
tank during the cleaning process may not be necessary if the cleaning agents
are controlled so as to not affect the permeate quality. (Ans. 6). The
Examiner states that the frequency of the cleaning event can be optimized
depending on the quality and quantity of water to be treated. (Ans. 4-9).
Regarding the rejections over the combined teachings of Smith and
Del Vecchio, Appellants contend that Smith teaches away from the use of
any tank draining step. (App. Br. 8). Appellants contend that the teachings
in Smith are contrary to any combination with Del Vecchio. (App. Br. 9).
Appellants contend that Figure 4 of Smith does not describe a process in
which the tank is drained. (App. Br. 10). Appellants acknowledge that Del
Vecchio describes a preferred embodiment wherein the deep cleanings occur
over several hours. However, Appellants contend that it would not have
been obvious to perform a cleaning process that takes several hours once per
week if once per month is adequate. 3 (App. Br. 11).

3 In response to the stated rejections, Appellants have addressed several
claims under separate headings (identifying a specific claim or groups of
claims). The discussion in the Brief for each of these claims is limited to the
discussion of specific portions of the Smith reference and specific portions
of the Del Vecchio reference. (App. Br. 11-20). After careful consideration
of this discussion, it is determined that, for all the claims subject to these
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Application 09/916,247

Regarding the rejection over Del Vecchio, Appellants contend that
Del Vecchio does not teach that varying the deep cleanings frequency
achieves a particular result. (App. Br. 16). Appellants contend that the
teachings of Del Vecchio would not lead to a cleaning frequency of at least
once per week. (App. Br. 17). Appellants further contend that the
parameters of the claimed invention are chosen to achieve a defined goal, a
reduced rate of decline in the membrane permeability between recovery
cleanings, whereas Del Vecchio teaches no goal to be achieved by
proactively modifying the cleaning frequency. (App. Br. 17).
The question before us is: Did Appellants identify reversible error in
the Examiner’s rejections under § 103? We answer this question in the
negative. The issue turns on whether a person of ordinary skill in the art
would have recognized that membranes normally immersed in water
containing solids for separating water from solids would have required
periodic cleaning and therefore would have optimized the cleaning
frequency during the separation process.
We have thoroughly reviewed each of Appellants’ arguments for
patentability. However, we are in complete agreement with the Examiner
that the claimed subject matter is not patentable within the meaning of § 103
in view of the applied prior art. Accordingly, we will sustain the Examiner’s
rejections.
rejections, Appellants’ principal argument is that the cited portions of the
Smith and Del Vecchio references do not teach the subject matter of the
independent claim 26. We have considered all of Appellants’ allegations for
patentability.
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Application 09/916,247

We make the following Findings of Fact (FF) from the record
presented in this appeal:
(1) Membranes are known for separating a permeate lean in
solids from a feed water rich in solids. Membranes have
a retentate side in fluid communication with the feed
water and a permeate side at which permeate is
collected. (Spec. 1).
(2) Filtered feed water permeates through the walls of the
membranes under the influence of a transmembrane
pressure differential between the retentate side of the
membranes and the permeate side of the membranes.
(Spec. 1).
(3) Solids in the feed water are rejected by the membranes
and remain on the retentate side of the membranes.
(Spec. 1).
(4) It has been recognized that it is important to keep
membranes used in such systems clean because, after
some period of use, a fouling film can form on the
membranes, thereby reducing the flow of permeate
through the membrane. As the permeability of
membranes decreases, the yield of the process similarly
decreases or a higher transmembrane pressure is
required to sustain the same yield. (Spec. 1; Smith, col.
1, ll. 1-30; and Del Vecchio, col. 1, ll. 33-43).
(5) The solids present in the feed water in solution, in
suspension or as precipitates may further include a
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Application 09/916,247

variety of substances, some not actually solid, including
colloids, microorganisms, suspended solids, and poorly
dissolved organic or inorganic compounds, and others.
(Spec. 1; Smith, col. 1, ll. 33-52; and Del Vecchio, col.
1, ll. 33-43).
(6) To prevent the decreased yield of the process or the
increased transmembrane pressure from becoming
unacceptable, the membranes must be cleaned. (Spec. 1;
Smith, col. 1, ll. 1-30; and Del Vecchio, col. 1, ll. 33-
43).
(7) Chemical cleaning solutions are known to be utilized for
cleaning surfaces of the membranes. (Spec. 2-3; Smith,
col. 12, ll. 9-19; and Del Vecchio, col. 3, ll. 34-38).
(8) Smith discloses that the concentration of the cleaning
fluid and the duration of the contact of the cleaning fluid
with the membrane are variable and has a dominant
affect on the cleaning process. (Smith, col. 14, ll. 6-17;
Figure 1).
(9) Smith discloses that depending upon the toxicity of the
bacterial population to be cleaned, as little as 10 ppm of
the cleaning fluid can be effective. (Smith, col. 14, ll.
34-36)
(10) Smith's Figure 4 depicts plotted results of a pilot plant
test in which the effect of various back-flushes utilizing
various solution (i.e., chemical solution/water/permeate),
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Application 09/916,247

each having a duration of 30 min, and carried out
sequentially. (Smith, col. 18, ll. 30-40).
(11) Smith discloses that draining the tank is not necessary
during the cleaning process and is an undesirable
alternative. (Smith, col. 10, ll. 64-68).
(12) Del Vecchio discloses the membranes should be subject
to periodic pulse cleanings and deep cleanings. (Del
Vecchio, col. 9, ll. 48-56).
(13) Del Vecchio discloses the pulse cleanings can be
conducted for varying time intervals including frequency
and duration. (Del Vecchio, col. 9, l. 49 to col. 10, l. 8).
(14) Del Vecchio discloses cleaning membranes which
comprises draining the water to be filtered from a
compartment containing the membranes, refilling the
compartment with a cleaning chemical, soaking the
membranes with the cleaning chemical for a period of
time required for the cleaning, draining the cleaning
chemical from the compartment, and then re-filling the
compartment. (Del Vecchio, col. 11, l. 47 to col. 12, l.
48).
(15) Del Vecchio discloses that the deep cleaning can be
conducted for varying time intervals including
frequencies and durations depending on the needs of the
system and the rate at which the membranes are fouled.
(Del Vecchio, col. 12, ll. 11-29).
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(16) Del Vecchio discloses despite significant advances in the
art of filter cleaning and the purported ability of such
proposed systems to prolong the throughput rate of the
membranes used as filters, it has been discovered that, in
some instances, the membranes must eventually be
removed from the process for a thorough cleaning such
as a deep chemical cleaning. (Del Vecchio, col. 2, ll. 57-
63).
(17) Del Vecchio discloses there are several drawbacks to
performing deep cleanings including the need to remove
a filter from the system. The process is time consuming,
expensive, labor intensive, and often requires that the
system be at least partially shut down during the
cleaning process while the filter is removed. (Del
Vecchio, col. 2, ll. 57-63).

PRINCIPLES OF LAW
Under 35 U.S.C. § 103, the factual inquiry into obviousness requires a
determination of: (1) the scope and content of the prior art; (2) the
differences between the claimed subject matter and the prior art; (3) the level
of ordinary skill in the art; and (4) secondary considerations, if any. See
Graham v. John Deere Co., 383 U.S. 1, 17-18 (1966). “[A]nalysis [of
whether the subject matter of a claim is obvious] 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 Int’l Co. v. Teleflex Inc.,
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127 S. Ct. 1727, 1740-41 (2007). “[I]f a technique has been used to improve
one device, and a person of ordinary skill in the art would recognize that it
would improve similar devices in the same way, using the technique is
obvious unless its actual application is beyond his or her skill.” Id. See also
DyStar Textilfarben GmBH & Co. Deutschland KG v. C.H. Patrick Co.,
464 F.3d 1356, 1361 (Fed. Cir. 2006) (“The motivation need not be found in
the references sought to be combined, but may be found in any number of
sources, including common knowledge, the prior art as a whole, or the
nature of the problem itself.”).

ANALYSIS
Applying the preceding legal principles to the Factual Findings (FF)
in the record of this appeal, we determine that the Examiner has established
a prima facie case of obviousness, which prima facie case has not been
adequately rebutted by Appellants’ arguments. As shown by FF (1-6)
above, it has been recognized that it is important to keep membranes used in
such systems clean because, after some period of use, a fouling film can
form on the membranes, thereby reducing the flow of permeate through the
membranes. The occurrence of reduced flow through the membranes is
recognized by the reduced yield of the permeate and/or the need for a higher
transmembrane pressure to sustain the same permeate yield. (FF (4)).
Chemical cleaning solutions were known to have been utilized in cleaning
membrane filtering systems to prevent the decreased yield of the filtered
product or the need for a higher transmembrane pressure. (FF (7)).
Therefore, a person of ordinary skill in the art would have recognized that
the concentration of the cleaning fluid, the duration of the contact of the
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cleaning fluid with the membranes, and the cleaning frequency affect the
effectiveness and efficiency of the membranes in the above fluid separation
process. (FF (8-9)). In other words, a person of ordinary skill in this art
would have recognized that the cleaning frequency, duration of the cleaning,
and the concentration of the cleaning solution utilized are all result effective
variables. Accordingly, it would have been prima facie obvious to one of
ordinary skill in the art to employ the optimum frequency, duration of the
cleaning and concentration of the cleaning fluid to achieve optimal
performance of the filtering system. Appellants have not established that the
scheduled cleaning events specified by the claimed invention achieve
unobvious and unexpected results.
As set forth above (FF (16)), Del Vecchio is evidence that a person of
ordinary skill in the art of filter cleaning would have recognized that the
membranes must eventually be removed from the filtering process for a
thorough cleaning such as a deep chemical cleaning. A person of ordinary
skill in the art would have recognized that there are several drawbacks to
performing deep cleaning, including the need to remove a filter from the
system. (FF (17)). The deep cleaning process is time consuming,
expensive, labor intensive, and often requires that the system be at least
partially shut down during the cleaning process. (FF (17)). A person of
ordinary skill in the art would have had sufficient skill to have selected a
more frequent cleaning cycle if he were to avoid the drawbacks associated
with the deep cleaning on a more frequent basis.
Appellants’ arguments regarding the failure of Smith to disclose
draining the tank for cleanings are not persuasive. As set forth above, the
record establishes that a person of ordinary skill in the art would have
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recognized that it may have been necessary to drain the tank periodically for
the purpose of performing deep cleanings. Smith’s Figure 4 is exemplary
that cleaning cycles can occur in repetition. A person of ordinary skill in the
art would have understood from the entire disclosures of Smith and Del
Vecchio that several cleaning events could occur subsequent to one another.
(FF (4-17)).
The Examiner finds that the frequency of the cleaning event can be
optimized. (Ans.4-9). We agree. Several factors must have been taken into
account when determining the proper cleaning intervals. A person of
ordinary skill in the art would have understood that these factors included
the quality and quantity of water to be treated, the concentration of the
cleaning solution, the duration of the cleaning cycle, and the need for
periodic deep cleaning cycles. (FF (4-9, 15)). Appellants have not asserted
that a person of ordinary skill in the art would have been unable to recognize
that these factors would have an affect on the cleaning efficiency and
effectiveness. Appellants have not asserted that the claimed invention
achieves an unexpected result.4
Del Vecchio is further evidence that persons of ordinary skill in the art
would have recognized that both pulse cleaning and deep cleanings can be
conducted for varying time intervals including frequency and duration. (FF
(12-17)). As set forth above, persons of ordinary skill in the art would have

4 The issue presented in our prior Decision 2006-2492 was for an
anticipation rejection. In this prior Decision, we did not make a
determination as to whether the Smith and Del Vecchio references would
have rendered the claimed subject matter obvious to a person of ordinary
skill in the art.

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recognized that the quality and quantity of water to be treated and the
concentration of the cleaning solution would have an affect on the frequency
and duration of the cleaning events. (FF (4-9)). A person of ordinary skill
in the art would have recognized that the rate of decline of a membrane that
is fouled is faster than non-fouled membrane. Thus, a person of ordinary
skill in the art would have reasonably selected cleaning intervals to achieve
optimal performance of the filtering system. As set forth above, Appellants
have not established that the scheduled cleaning events specified by the
claimed invention achieve unobvious and unexpected results.
We do not find Appellants’ allegations for patentability of the
dependent claims persuasive for the reasons set forth above and in the
Answer.
After consideration of the entire record, we determine that a person of
ordinary skill in the art would have recognized that membranes normally
immersed in water containing solids would have required periodic cleaning
and therefore would have optimized the cleaning frequency for cleaning the
membranes used in the fluid separation process. For the foregoing reasons
and those stated in the Answer, we affirm the rejections presented in this
appeal.

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ORDER
All the rejections of the claims on appeal are affirmed.
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

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cam
SCOTT R. PUNDSACK
BERESKIN & PARR
BOX 401
40 KING STREET WEST
TORONTO ON M5H 3Y2 CA CANADA

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