Ex Parte Litwin et al

Patent Trial and Appeal BoardSep 25, 2012

11479635 (P.T.A.B. Sep. 25, 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. 11/479,635 06/30/2006 Robert Z. Litwin U73.12-0066 9469 12208 7590 09/26/2012 Kinney & Lange, P.A. c/o CPA Global P.O. Box 52050 Minneapolis, MN 55402 EXAMINER NGUYEN, HOANG M ART UNIT PAPER NUMBER 3748 MAIL DATE DELIVERY MODE 09/26/2012 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 PATENT TRIAL AND APPEAL BOARD ____________ Ex parte ROBERT Z. LITWIN, ANDREW J. ZILLMER and NATHAN J. HOFFMAN ____________ Appeal 2010-004705 Application 11/479,635 Technology Center 3700 ____________ Before JOHN C. KERINS, PHILLIP J. KAUFFMAN and GAY ANN SPAHN, Administrative Patent Judges. KERINS, Administrative Patent Judge. DECISION ON APPEAL Appeal 2010-004705 Application 11/479,635 2 STATEMENT OF THE CASE Robert Z. Litwin et al. (Appellants) seek our review under 35 U.S.C. § 134 of the Examiner’s final rejection of claims 1, 3, 4, 10, 16, 17 and 19- 21. Claims 2, 5-9, 11-15 and 18 are canceled. We have jurisdiction under 35 U.S.C. § 6(b). We AFFIRM-IN-PART and designate the affirmed rejection as a NEW GROUND OF REJECTION UNDER 37 C.F.R. § 41.50(b). THE INVENTION Appellants’ claimed invention is to a high temperature solar power tower system and method. Claim 1, reproduced below, is illustrative: 1. A high temperature solar power tower system comprising: a molten fluoride salt heat transfer medium capable of being heated to a temperature of at least about 1800 degrees Fahrenheit; a high temperature solar receiver for heating the molten salt formed from a material selected from the group consisting of: an iron based alloy, a nickel based alloy, and a cobalt based alloy; and a Brayton cycle energy conversion system for generating power with the heated molten salt. THE REJECTIONS The Examiner has rejected: (i) claims 1, 3, 10, 16 and 19-21 under 35 U.S.C. § 103(a) as being unpatentable over Litwin (US 2004/0244376 A1, pub. Dec. 9, 2004) in view of Marko (US 5,862,800, iss. Jan. 26, 1999), Van Hook (US 4,668,494, iss. May 26, 1987) and A.K. Misra et al., Estimated heats of fusion of fluoride Appeal 2010-004705 Application 11/479,635 3 salt mixtures suitable for thermal energy storage applications, 1-2 (May 1986) (Smithsonian/NASA ADS Physics Abstract Service, accessed at http://adsabs.harvard.edu/abs/1986STIN...8631982M) (last accessed Sep. 27, 2006) (hereinafter “Misra”); and (ii) claims 4 and 17 under 35 U.S.C. § 103(a) as being unpatentable over Litwin, Van Hook, Marko, Misra and Briscoe (US 6,346,349 B1, iss. Feb. 12, 2002). ANALYSIS Claims 1, 3, 10, 16 and 19-21--Obviousness--Litwin/Marko/Van Hook/Misra Appellants do not present separate arguments for any of the claims. Because Appellants’ arguments address similar or identical limitations present in independent claims 1, 10 and 19, we treat these claims as representative, and claims 3, 16, 20 and 21 will stand or fall with their respective base claim. The Examiner’s grounds of rejection states that Litwin discloses a solar power tower system, but “does not disclose 1) the operating temperature of at least 1800 degrees F, 2) the material for forming the solar receiver, and 3) the heat transfer medium is a fluoride molten salt.” Ans. 3. Van Hook is relied on as evidence that it was known in the art at the time of the present invention that a heat transfer system employing solar energy using molten salt could operate by heating the molten salt to a temperature up to 2000 degrees Fahrenheit. Ans. 3-4. Marko is relied on as evidence that it was known to use nickel-based alloys for forming elements in a solar receiver, and Misra is relied on as teaching that the use of fluoride salt mixtures as heat transfer fluids in a thermal storage system was known. Ans. 4. Appeal 2010-004705 Application 11/479,635 4 Appellants’ arguments distill down to: (a) “[t]here is no articulated reasoning for substituting Van Hook’s salt for Litwin’s metal [as the heat transfer fluid];” (b) “[t]here is no articulated reasoning for using a material that is prohibited from being used, and then suggest that another material not disclosed in Marko or Litwin be substituted for either material;” (c) [t]here is no articulated reasoning for taking a material from a system that involves solidification of the salt and using it in a system that generates electrical energy without solidification (that would render it inoperative);” and (d) [t]here is no recognition of the problem solved by the present invention. App. Br. 7. Taking the last of these arguments first, Appellants’ Specification notes that, “[i]n general, the higher the temperature of the heat transfer fluid, the more efficient the solar tower power system. Thus, heat transfer fluids and systems capable of withstanding higher temperatures are desirable.” Spec., p. 2, ll. 4-6. This is the only statement we could find in the Specification as possibly identifying a problem facing Appellants. Both Litwin and Van Hook recognize these very issues. Litwin, p. 2, paras. [0024], [0025], [0037] and [0048]; Van Hook, col. 4, ll. 19-22 and ll. 57-66, col. 5, ll. 11-20 and ll. 24-26, col. 6, ll. 14-19. Turning to argument (a) above, the Examiner relied on Van Hook as disclosing use of operating temperatures higher than those disclosed by Litwin, as well as for the concept of using molten salt at such high temperatures. We are not persuaded that the Examiner did not adequately articulate the relevance of the Van Hook reference. Van Hook, in disclosing the elevated temperatures, notes that high-temperature operation results in Appeal 2010-004705 Application 11/479,635 5 the most effective use of energy, as does Litwin itself. Van Hook, col. 4, ll. 57-59; Litwin, p. 2, para. [024]. Argument (b) above is directed to the Examiner’s citation of Marko as teaching the use of a nickel-based alloy in a solar receiver. We agree with Appellants that the specific alloy (alloy 625, and more specifically Inconel 625) does not appear to be suitable for use at temperatures of 1800° F. and above. Notwithstanding, the Examiner points out that Litwin itself discloses that nickel-based alloys would be suitable for use at temperatures up to the operating temperatures (1445° F. and 1618° F.) disclosed therein. Litwin, paras. [0025], [0037] and [0048]. Not only that, Van Hook discloses that nickel-based alloys (“inconel or incoloy”) are suitable for use in handling the flowing molten salt at the disclosed high operating temperatures. Van Hook, col. 6, ll. 14-19.1 As such, the use of a suitable nickel-based alloy was known and would have been obvious to use in the Examiner’s proposed modification to the Litwin system. Argument (c) appears to be founded upon an attack of the Misra reference individually. The reference discloses that fluoride salts are suitable for use in storing thermal energy for use with solar dynamic power systems. Whether, in the specific use disclosed in Misra, such salts would be called upon to undergo a phase change is not germane to the Examiner’s use of the teachings of Misra. Van Hook, while specifically disclosing the 1 Van Hook specifically discloses the use of nickel-based alloys for the tubes in an ammonia burner, which is the element used to heat the molten salt up to its operating temperature. As the solar receiver in the Litwin reference is the element used to heat the molten salt up to its operating temperature, a person of ordinary skill in the art would find that the use of nickel-based alloys in Van Hook would be applicable to the solar receiver of Litwin. Appeal 2010-004705 Application 11/479,635 6 use of carbonate salts, also notes that persons skilled in the art “will be able to select other salt formulations . . . that are suitable for these operating temperatures.” Van Hook, col. 5, ll. 17-20. Accordingly, we are not persuaded that it would not have been obvious to select a fluoride salt for use in the Litwin system as modified to operate at temperatures of 1800° F. and above. The Examiner’s rejection of claims 1, 3, 10, 16 and 19-21 is affirmed. Since our reasons for affirming differ to some extent from those presented by the Examiner, particularly with respect to the limitation calling for use of a nickel-based alloy (as one of three options in the Markush group) for the solar receiver, it might be considered that Appellants have not had a fair opportunity to react to the thrust of the rejection as it presently stands. In re Kronig, 539 F.2d 1300, 1302–03 (CCPA 1976); see also In re Kumar, 418 F.3d 1361, 1368 (Fed. Cir. 2005). As such, we designate our affirmance of the rejection as a new ground of rejection pursuant to 37 C.F.R. § 41.50(b). Claims 4 and 17--Obviousness-- Litwin/Van Hook/Marko/Misra/Briscoe The Examiner relies on Briscoe as disclosing “that it’s well known to use FLiNaK as a heat transfer fluid in a thermal storage system,” and concludes that it would have been obvious to use FLiNaK as the molten salt in the Litwin system “for the purpose of achieving appropriate heat transfer rate.” Ans. 4-5. Appellants point out that Briscoe discloses the use of FLiNaK as an electrolyte for a battery, and not as a heat transfer fluid in a thermal storage system. App. Br. 7-8. The Examiner counters that an electrolyte transfers heat to the anode and cathode in the battery. Ans. 7. Appeal 2010-004705 Application 11/479,635 7 The Examiner’s position is not supported by the evidence or other rational underpinnings. In re Kahn, 441 F.3d 977, 988 (Fed. Cir. 2006)(obviousness rejections must be supported by articulated reasoning with some rational underpinning), cited with approval in KSR Int'l Co. v. Teleflex, Inc., 550 U.S. 398, 418 (2007). The Examiner has not adequately explained how the Briscoe battery would be considered to be a thermal storage system by persons of ordinary skill in the art. The rejection of claims 4 and 17 is not sustained. CONCLUSIONS Appellants have not persuaded us that the subject matter of claims 1, 3, 10, 16 and 19-21 would not have been obvious over Litwin in view of Marko, Van Hook and Misra. The Examiner erred in concluding that the subject matter of claims 4 and 17 would have been obvious over Litwin, Van Hook, Marko, Misra and Briscoe. DECISION The decision of the Examiner to reject claims 1, 3, 10, 16 and 19-21 under 35 U.S.C. § 103(a) is AFFIRMED, but designated as a new ground of rejection under 37 C.F.R. § 41.50(b). The decision of the Examiner to reject claims 4 and 17 as being unpatentable is REVERSED. Regarding the affirmed rejection(s), 37 C.F.R. § 41.52(a)(1) provides "Appellant[s] may file a single request for rehearing within two months from the date of the original decision of the Board." Appeal 2010-004705 Application 11/479,635 8 In addition to affirming the Examiner's rejection(s) of one or more claims, this decision contains a new ground of rejection pursuant to 37 C.F.R. § 41.50(b). Section 41.50(b) provides “[a] new ground of rejection pursuant to this paragraph shall not be considered final for judicial review.” Section 41.50(b) also provides that Appellants, WITHIN TWO MONTHS FROM THE DATE OF THE DECISION, must exercise one of the following two options with respect to the new grounds of rejection to avoid termination of the appeal as to the rejected claims: (1) Reopen prosecution. Submit an appropriate amendment of the claims so rejected or new evidence relating to the claims so rejected, or both, and have the matter reconsidered by the examiner, in which event the proceeding will be remanded to the examiner . . . (2) Request rehearing. Request that the proceeding be reheard under § 41.52 by the Board upon the same record . . . Should Appellants elect to prosecute further before the Examiner pursuant to 37 C.F.R. § 41.50(b)(1), in order to preserve the right to seek review under 35 U.S.C. §§ 141 or 145 with respect to the affirmed rejection, the effective date of the affirmance is deferred until conclusion of the prosecution before the Examiner unless the affirmed rejection is overcome. If Appellants elect prosecution before the Examiner and this does not result in allowance of the application, abandonment or a second appeal, this case should be returned to the Patent Trial and Appeal Board for final action on the affirmed rejection, including any timely request for rehearing thereof. Appeal 2010-004705 Application 11/479,635 9 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-IN-PART; 37 C.F.R. § 41.50(b) hh