11189213 (B.P.A.I. Jan. 19, 2012)

Ex Parte Sirkar et al

Board of Patent Appeals and InterferencesJan 19, 2012

11189213 (B.P.A.I. Jan. 19, 2012)

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. 11/189,213 07/26/2005 Kamalesh K. Sirkar 94350.00022 2672 72535 7590 01/19/2012 MCCARTER & ENGLISH, LLP STAMFORD CANTERBURY GREEN 201 BROAD STREET, 9TH FLOOR STAMFORD, CT 06901 EXAMINER MENON, KRISHNAN S ART UNIT PAPER NUMBER 1777 MAIL DATE DELIVERY MODE 01/19/2012 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 BOARD OF PATENT APPEALS AND INTERFERENCES ________________ Ex parte KAMALESH K. SIRKAR and Baoan Li ________________ Appeal 2010-007676 Application 11/189,213 Technology Center 1700 ________________ Before CHARLES F. WARREN, BEVERLY A. FRANKLIN, and MARK NAGUMO, Administrative Patent Judges. NAGUMO, Administrative Patent Judge. DECISION ON APPEAL Appeal 2010-007676 Application 11/189,213 2 A. Introduction1 Kamalesh K. Sirkar and Baoan Li (“Sirkar”) timely appeal under 35 U.S.C. § 134(a) from the final rejection2 of claims 1-16, 22, and 23.3 We have jurisdiction. 35 U.S.C. § 6. We REVERSE. The subject matter on appeal relates to an improved device for the desalinization of brine by membrane distillation. The membrane comprises porous hydrophobic hollow fibers that have an interior diameter on the order of 200-330 μm and wall thicknesses on the order of 50 to 150μm. (Spec. 13, ll. 10-12.) Hot brine is passed over the membranes, i.e., over the exterior of the hollow fibers. Water vapor can pass through the pores into the interior of the hollow fibers, but liquid water and the salt dissolved in the water cannot penetrate the pores, which typically have a diameter of 0.1 to 0.5 μm, due to the surface tension of liquid water. (Id. at 3, ll. 10-11.) Wetting of the membrane, which is said to be deleterious to membrane distillation, is further prevented by providing an ultrathin hydrophobic porous coating, which is said to permit “substantially unimpeded water vapor permeance through the fiber walls.” (Id. at 5, ll. 10-15.) Prior art ultrathin hydrophobic 1 Application 11/189,213, Desalination Devices and Systems Using Porous Hydrophobic Hollow Fibers and Hydrophobic Porous Coatings, filed 26 July2005, claiming the benefit of a provisional application filed 28 July 2004. The specification is referred to as the “213 Specification,” and is cited as “Spec.” The real party in interest is listed as the New Jersey Institute of Technology. (Appeal Brief, filed 30 November 2009 (“Br.”), 1.) 2 Office action mailed 15 June 2009 (“Final Rejection”; cited as “FR”). 3 Claims 17-21 have been withdrawn from consideration and are not before us. (FR 1; Br. 1.) Appeal 2010-007676 Application 11/189,213 3 coatings reportedly had pores with diameters of 5-15 Å. (Sirkar (2001) at 16; Sirkar (2001) is cited at Spec. 4; a full citation is provided infra at n.5.) The improvement is said to lie in the provision of ultrathin hydrophobic porous coating having pore diameters of 30 Å to 5 μm in diameter. (Spec. 42, ll. 14-15; 67, ll. 11-12.) The ultrathin hydrophobic coatings are said to range in thickness from about 500 Å [50 nm] to about 15 μm. (Id. at 42, ll. 15-16; 67, ll. 12-13.) The improved membranes are said to enable a high flux of water vapor through the membranes. (Id. at 5, ll. 21-24.) Representative Claim 1 reads: 1. A system for desalination of brine, comprising: a module that includes a membrane formed by a plurality of porous hydrophobic hollow fibers, each of the plurality of porous hydrophobic hollow fibers defining an internal and an external surface and including a hydrophobic porous coating on at least one of said internal surface and said external surface, wherein the hydrophobic porous coating exhibits a pore size of at least 30 A; wherein the hydrophobic porous coating is effective to prevent salt intrusion and pore wetting of the porous hydrophobic hollow fibers, and wherein each of the plurality of coated hollow fibers is characterized by a wall thickness and an inner diameter effective to establish a steady state water vapor permeation flux of at least 20 kg/m2-hr. (Claims App., Br. 17; indentation, paragraphing, and emphasis added.) Appeal 2010-007676 Application 11/189,213 4 The Examiner maintains the following grounds of rejection:4 A. Claims 1-16, 22, and 23 stand rejected under 35 U.S.C. § 103(a) in view of the teachings of Sirkar (2001).5 B. Claims 1-16, 22, and 23 stand rejected under 35 U.S.C. § 103(a) in view of the combined teachings of Hanemaaijer6 and Sirkar (2001). B. Discussion Findings of fact throughout this Opinion are supported by a preponderance of the evidence of record. Initially, we find that Sirkar has not raised arguments for the separate patentability of any claim apart from claim 1. The appealed claims thus stand or fall with claim 1. 37 C.F.R. § 41.37(c)(vii) (2007). Sirkar urges that the Examiner erred by failing to “distinguish crucial differences between membrane pore size and coating layer pore size.” (Br. 7, last para.) As a result, in Sirkar’s view, the Examiner, inter alia, mistakenly imputed membrane porosity parameters to coating porosity parameters. (Id. at para. bridging 7-8.) 4 Examiner’s Answer mailed 3 February 2010 (“Ans.”). 5 Kamalesh K. Sirkar and Yingie Qin, Novel Membrane and Device for Direct Contact Membrane Distillation Based Desalination Process, Desalination and Water Purification Research and Development Program Report No. 87 to the U.S. Department of the Interior, Bureau of Reclamation (2001); also referred to as “the 2001 Report.” 6 Jan Hendrik Hanemaaijer and Jan Willem Van Heuven, Method for the Purification of a Liquid by Membrane Distillation, in Particular for the Production of Desalinated Water from Seawater or Brackish Water or Process Water, U.S. Patent 6,716,355 B1 (6 April 2004), filed as the national stage of an international application filed in 2000. Appeal 2010-007676 Application 11/189,213 5 The Examiner finds that Sirkar (2001) discloses a system for desalinization of brines comprising a hollow fiber membrane module having a thin coating of a hydrophilic polymer. (Ans. 5.) The Examiner finds further that the 2001 Report teaches a pore size [of the coating layer] of 5-15 Å, but not a coating pore size of at least 30 Å. (Id. at 6, last para.) According to the Examiner, Sirkar (2001) teaches “that the flow geometry, operating differential temperature, heat transfer rate, etc[.] could be optimized to achieve higher fluxes.” (Id., citing and reproducing in full Sirkar (2001) pages 13-14.) Notably, the Examiner does not find any express teaching in the reproduced passage suggesting that the pore size of the coating layer be enlarged. Rather, the Examiner argues that: [i]t is well known and also common sense that larger the pore size, larger the flux. According to Sirkar in the paragraph quoted above, the condition for the membrane to function as desired is that there should be no salt intrusion and pore wetting in the hydrophobic layer, which means that the pore size can be optimized to increase flux while preventing pore wetting and salt intrusion. (Id. at 8, last para.; emphasis added.) The difficulty with the Examiner’s argument is that the Examiner has not cited any credible evidence of record that persons having ordinary skill in the art would have had a reasonable expectation that the coating pore size could have been optimized in the greater than 30 Å range now recited, while continuing to prevent pore wetting and salt intrusion. In this regard, it is striking that the first question posed by the 2001 Report regarding the analysis of the experimental results is, “Did the hydrophobic coating prevent salt intrusion into the membrane pore and prevent membrane wetting?” Appeal 2010-007676 Application 11/189,213 6 (Sirkar (2001) 13, ll. 3-4.) Although the 2001 report appears to be optimistic, it cautions that, “[t]o settle the question of prevention of pore wetting by the coating conclusively . . . will require an experiment running continuously for 10-30 days.” (Id. at 2d full para.) It should also be noted that the silicone coating on Module 4 is characterized as an “ultrathin coating having 5-15 Å pores specified by us; manufactured by AMT Inc.” (Id. at 16; emphasis added.) Moreover, although Sirkar (2001) lists at least three factors to explain the “very low water permeation characteristics” of Module 5, (id. at 13, last para.), the first of which is that the “novel fluoropolymer coating on Module 5 is likely to have a very low water permeation characteristics” (id., 2d sentence), the 2001 report does not suggest that larger pores would likely result in increased water permeation flux. Rather, cross flow velocity and larger diameter fibers are suggested as ways to improve the efficiency of the system. (Id. at ll. 40-45.) The weight of the evidence is that Sirkar (2001) was not certain that the coating layer having 5-15 Å pores—a size that was deliberately selected—would necessarily serve the intended purpose of preventing membrane wetting under membrane-distillation conditions of practical interest. Thus, it does not follow that the artisan would have expected that a still larger pore size would have permitted an increased flux while continuing to prevent pore wetting and salt intrusion under conditions of actual use. In the absence of evidence that persons having ordinary skill in the art would have thought otherwise, we conclude that the Examiner’s Appeal 2010-007676 Application 11/189,213 7 holding of obviousness is based on hindsight gained from the 213 Specification.7 We find the Examiner’s reliance on Hanemaaijer to be unpersuasive vis-à-vis the appealed claims, as Hannemaaijer only discusses the pore diameters of the membranes, not of hydrophobic coatings on the membranes. We therefore REVERSE the rejections of record. C. Order We REVERSE the rejection of claims 1-16, 22, and 23 under 35 U.S.C. § 103(a) in view of the teachings of Sirkar. We REVERSE the rejection of claims 1-16, 22, and 23 under 35 U.S.C. § 103(a) in view of the combined teachings of Hanemaaijer and Sirkar. REVERSED sld 7 Nothing in this Opinion should be read as an endorsement of arguments presented by Sirkar or by the Examiner that we have not discussed.