Ex Parte Rabie et al

Board of Patent Appeals and Interferences

Dec 12, 2008

10461687 (B.P.A.I. Dec. 12, 2008)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte HAMID R. RABIE, HIDAYAT HUSAIN,
and HENRY BEHMANN
____________

Appeal 2008-3306
Application 10/461,687
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 1, 3, 12-16, 35, 36, and 41-43, the only
claims pending in this application. We have jurisdiction under 35 U.S.C.
§ 134.
We AFFIRM
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Application 10/461,687

Appellants’ invention is directed to a method of chemical cleaning
one or more ultrafiltration or microfiltration membranes normally immersed
in water containing solids that become dirty or fouled during normal
operation. Representative independent claims 1 and 35, as presented in the
Brief, appear below:
1. A method for cleaning one or more membranes normally
immersed in water containing solids held at ambient pressure in a tank
and used to produce a permeate on the insides of the membranes,
comprising the steps of:

(a) cleaning the membranes to increase the permeability of the
membranes,

(b) after step (a), performing one or more cleaning events per
week over a period of at least 15 days, each cleaning event further
comprising the steps of flowing a chemical cleaner through the
membranes to provide a chemical cleaner in or adjacent the
membranes for a period of time; and,

(c) choosing the concentration of the chemical cleaner and the
period of time such that the cleaning events reduce the rate of a
decline in permeability of the membranes over the period of at least
15 days;

wherein steps (a) and (b) are preformed in repeated cycles.

35. A method for cleaning one or more hollow fiber membranes
normally immersed in water containing solids held at ambient
pressure in a tank and used to produce a permeate on the insides of the
membranes, comprising the steps of:

(a) performing recovery cleanings to increase the permeability
of the membranes from time to time; and

(b) between recovery cleanings, performing one or more
cleaning events per week, each cleaning event comprising the steps of
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flowing a chemical cleaner through the membranes to provide a
chemical cleaner in or adjacent the membranes for a period of time.

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

The Examiner rejected claims 1, 3, 12-16, 35, 36, and 41-43 under
35 U.S.C. § 103 as obvious over Smith.
The Examiner rejected claims 1, 3, 12-16, 35, 36, and 41-43 under
35 U.S.C. § 103 as obvious over Del Vecchio.
The Examiner rejected claims 1, 3, 12-16, 35, 36, and 41-43 under
35 U.S.C. § 103 as obvious over the combined teachings of Smith and Del
Vecchio.
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. 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 Smith and the combined teachings of
Smith and Del Vecchio, Appellants contend that Smith's Figure 4 discloses
only three relevant cleanings, numbered (1), (5), and (6), involving cleaning
chemicals with a chosen concentration while the remaining cleaning events
are performed with water which are outside of the scope of the invention.
Appellants contend that cleanings (1) and (5) are about 10 days apart. Each
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cleaning is an isolated exploratory event performed as part of a test to verify
the effectiveness of various biocidal solutions. Appellants contend that
Smith does not teach repeating these cleanings in a cycle. Appellants
contend that even if cleanings (1) and (6) in Smith's Figure 4 were equated
with step (a) of the present claim 1, there is still no disclosure of a
subsequent step of performing one or more cleaning events per week over a
period of at least 15 days as required by step (b) of claim 1, nor a disclosure
of steps (a) and (b) as in the present claim 1 being performed in repeated
cycles.1 (App. Br. 5-6).
Regarding the rejection over Del Vecchio, Appellants contend that
Del Vecchio teaches only that the frequency of deep cleanings could vary
depending upon the needs of the system and that Del Vecchio does not teach
that the chemical concentration and contact time of the cleaning events
between recovery cleanings are variables that can effect any result.2 (App.
Br. 10-12).

1 In response to the stated rejections, Appellants have addressed several
claims under separate headings (specifically claims 1, 3, 35, and 43). The
discussion in the Brief for each of these claims is limited to the discussion of
Figure 4 of the Smith reference and a specific portion of the Del Vecchio
reference. (App. Br. 5-9). Appellants also have indicated that the subject
matter of claims 12-16, 36, 41, and 42 is patentable for the reasons set forth
in response to claims 1 and 35. (App. Br. 9-10). After careful consideration
of this discussion, it is determined that, for all the claims subject to these
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 claims 1 and 35. We have considered all of Appellants’
allegations for patentability.
2 In response to this rejection, Appellants have addressed independent claims
1 and 35 together under a separate heading. Regarding the remaining claims
(i.e., 3, 12-16, 36 and 41-43), Appellants have grouped the arguments
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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 and the concentration of the
cleaning fluid utilized in the 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.
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
together. (App. Br. 10-12). We have considered all of Appellants’
allegations for patentability.
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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
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).
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(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),
each having a duration of 30 min, and carried out
sequentially. (Smith, col. 18, ll. 30-40).
(11) Del Vecchio discloses the membranes should be subject
to periodic pulse cleanings and deep cleanings. (Del
Vecchio, col. 9, ll. 48-56).
(12) 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).
(13) Del Vecchio discloses that deep cleanings can be
conducted for varying time intervals including
frequencies and durations depending on the needs of the
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system and the rate at which the membranes are fouled.
(Del Vecchio, col. 12, ll. 11-29).
(14) Del Vecchio discloses despite significant advances in the
art of filter cleaning, and despite 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).
(15) Del Vecchio discloses there are several drawbacks to
performing deep cleanings including the need to remove
a filter from the system. This 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
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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.,
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
We initially begin our analysis of the subject matter on appeal by
determining the scope of the independent claims (1 and 35). The subject
matter of the independent claims is directed to a method for cleaning
membranes that are normally immersed in water containing solids. The first
step (a) requires cleaning the membranes to increase the permeability of the
membranes. This language does not specify a particular type of cleaning
event that is performed. That is, the cleaning event could occur through any
known cleaning event including mechanical scrubbing with or without the
use of a chemical cleaning solution, or the use of chemical cleaning solution
placed in contact with the membrane in the absence of mechanical
scrubbing. Step (b), performed after step (a), requires the use of a chemical
cleaner in or adjacent to the membrane. Thus, performing the step of
membrane cleaning utilizing a chemical cleaner in or adjacent to the
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membrane followed by performing the identical step would meet steps (a)
and (b) as specified in the independent claims.
Applying the preceding legal principles and the claim interpretation 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 membrane is recognized by the reduced yield of the permeate and/or a
higher transmembrane pressure 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 to prevent the decreased yield of
the filtering process or increase in the transmembrane pressure. (FF (7)).
Therefore, a person of ordinary skill in the art would have recognized that
variables that affect the cleaning of the membrane include the concentration
of the cleaning fluid and the duration of the contact of the cleaning fluid
with the membrane. (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 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
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scheduled cleaning events specified by the claimed invention achieve
unobvious and unexpected results.
Regarding the rejections over Smith, Appellants’ contentions are
directed to only Smith's Figure 4. This limited argument does not take into
account what a person of ordinary skill in the art would have understood
from the full disclosure of the Smith reference. Figure 4 is exemplary that
cleaning cycles can occur in repetition. A person of ordinary skill in the art
would have understood from the disclosure of the entire Smith reference that
several cleaning events could occur subsequent to one another. (e.g., see FF
(4-9)). A person of ordinary skill in the art would have understood that the
concentration of the cleaning solution would have an affect on the cleaning
efficiency and duration of the cleaning cycle. Appellants have not asserted
that a person of ordinary skill in the art would have been unable to recognize
that the concentration of the cleaning solution would have an affect on the
cleaning efficiency and duration of the cleaning cycle. Appellants have not
asserted that the claimed invention achieves an unexpected result.3
Del Vecchio is further evidence that persons of ordinary skill in the art
would have recognized that both pulse cleaning and the deep cleanings can
be conducted for varying time intervals including frequency and duration.
(FF (12-13)). As set forth above, persons of ordinary skill in the art would
have recognized that the concentration of the cleaning solution would have
an affect on the frequency and duration of the cleaning events.

3 The issue presented in our prior Decision 2006-2898 was for an
anticipation rejection. In this prior Decision, we did not make a
determination as to whether the Smith reference would have rendered the
claimed subject matter obvious to a person of ordinary skill in the art.

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We do not find Appellants’ allegations for patentability of the
dependent claims persuasive for the reasons set forth above and in the
Answer.
Regarding the rejection over Del Vecchio, Appellants contend that
Del Vecchio teaches only that the frequency of deep cleanings could vary
depending upon the needs of the system and that Del Vecchio does not teach
that the chemical concentration and contact time of the cleaning events
between recovery cleanings are variables that can affect any result. (App.
Br. 10-12).
Del Vecchio is further evidence that a person of ordinary skill in the
art would have recognized that both pulse cleaning and deep cleanings could
have been conducted for varying time intervals including frequency and
duration. (FF (11-15)). As set forth above, a person of ordinary skill in the
art would have 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 and effectiveness 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 the
appropriate concentration of the cleaning solution and the appropriate
cleaning intervals to achieve optimal performance of the filtering system.
As set forth above, Appellants have not established that the chemical
concentration and contact time of the cleaning events between recovery
cleanings specified by the claimed invention achieve unobvious and
unexpected results.
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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 solution concentration and
cleaning frequency of the process. For the foregoing reasons and those
stated in the Answer, we affirm the rejections presented in this appeal.
ORDER
The rejections of claims 1, 3, 12-16, 35, 36, and 41-43 under 35 U.S.C.
§ 103(a) are affirmed.
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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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BERESKIN AND PARR
40 KING STREET WEST
BOX 401
TORONTO ON M5H 3Y2 CA CANADA

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