Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Response to Amendment
The Amendment filed April 7, 2026 has been entered. Claims 1-24 remain pending in the application. Applicant’s amendments to the Claims have overcome the rejection of claim 8 under 35 U.S.C. §112(b) previously set forth in the previous Office Action mailed January 8, 2026. Therefore, the rejections of claim 8 has been withdrawn.
Response to Arguments
Applicant’s arguments filed April 7, 2026 in response to the Non-Final Office Action mailed January 8, 2026 have been fully considered but are persuasive only to the extent indicated below.
Applicant argues that the term “module” is sufficiently clear when read in light of the claims and specification because the claims and specification consistently describe each module as including a feed chamber, a vacuum chamber, and a membrane separating the feed chamber from the vacuum chamber. This argument is persuasive. In view of the claim language and the supporting disclosure, the term “module” is understood as the repeated membrane distillation unit including the recited feed chamber, vacuum chamber, and membrane. Accordingly, the prior rejection/objection under 35 U.S.C. §112(b) based on the term “module” is withdrawn.
Applicant further argues that the phrase “fluidically coupled” is sufficiently clear when read in light of the claims, specification, and drawings, and further notes that certain claims previously identified do not recite the phrase “fluidically coupled”. This argument is persuasive. The phrase “fluidically coupled”, as used in the claims and specification, reasonably indicates that the recited components are connected in a manner permitting fluid communication or fluid flow between the components. The fact that the connection may be direct or indirect does not, by itself, render the scope indefinite. Accordingly, the prior rejection/objection under 35 U.S.C. §112(b) based on the phrase “fluidically coupled” is withdrawn.
With respect to the rejection of claims 1-24 under 35 U.S.C. §103 over Khalifa in view of Falath, Applicant argues that Falath is not available as prior art because the relied upon subject matter in Falath, namely the carrier gas inlet fluidly connected to the feed zone and the introduction of carrier gas into the feed side, originated from a named inventor of the present application. Applicant submitted a declaration under 37 CFR 1.130 in support of this argument. The declaration has been considered and is deemed sufficient to disqualify Falath as prior art for the subject matter relied upon in the prior § 103 rejection. Accordingly, the prior rejection of claims 1-24 under 35 U.S.C. § 103 over Khalifa in view of Falath is withdrawn.
However, Applicant’s arguments are not persuasive that the application is in condition for allowance. Although Falath is no longer relied upon as prior art in the withdrawn §103 rejection, Falath remains available as a double patenting reference. A showing that a disclosure is not available as prior art under 35 U.S.C. §102 does not preclude reliance on the claims of the corresponding patent for purposes of statutory or nonstatutory double patenting. The present action therefore sets forth a new rejection of claims 1-24 on the ground of nonstatutory double patenting as being unpatentable over claims 1, 14, and 18 of Falath et al. in view of Khalifa et al.
The nonstatutory double patenting rejection is distinct from the withdrawn §103 rejection relied on Falath as prior art to supply the carrier-gas/feed-zone feature missing from Khalifa. The present nonstatutory double patenting rejection instead relied on the claims of the issued Falath patent as the double patenting reference, with Khalifa relied upon as a secondary prior art reference to show that the differences between the presently claimed multistage MS-VMD system and the claimed Falath subject matter would have been obvious. Accordingly, Applicant’s arguments and declaration overcome the prior § 103 rejection over Khalifa in view of Falath, but do not overcome the nonstatutory double patenting rejection set forth in this Office action.
Double Patenting
The nonstatutory double patenting rejection is based on a judicially created doctrine grounded in public policy (a policy reflected in the statute) so as to prevent the unjustified or improper timewise extension of the “right to exclude” granted by a patent and to prevent possible harassment by multiple assignees. A nonstatutory double patenting rejection is appropriate where the conflicting claims are not identical, but at least one examined application claim is not patentably distinct from the reference claim(s) because the examined application claim is either anticipated by, or would have been obvious over, the reference claim(s). See, e.g., In re Berg, 140 F.3d 1428, 46 USPQ2d 1226 (Fed. Cir. 1998); In re Goodman, 11 F.3d 1046, 29 USPQ2d 2010 (Fed. Cir. 1993); In re Longi, 759 F.2d 887, 225 USPQ 645 (Fed. Cir. 1985); In re Van Ornum, 686 F.2d 937, 214 USPQ 761 (CCPA 1982); In re Vogel, 422 F.2d 438, 164 USPQ 619 (CCPA 1970); In re Thorington, 418 F.2d 528, 163 USPQ 644 (CCPA 1969).
A timely filed terminal disclaimer in compliance with 37 CFR 1.321(c) or 1.321(d) may be used to overcome an actual or provisional rejection based on nonstatutory double patenting provided the reference application or patent either is shown to be commonly owned with the examined application, or claims an invention made as a result of activities undertaken within the scope of a joint research agreement. See MPEP § 717.02 for applications subject to examination under the first inventor to file provisions of the AIA as explained in MPEP § 2159. See MPEP § 2146 et seq. for applications not subject to examination under the first inventor to file provisions of the AIA . A terminal disclaimer must be signed in compliance with 37 CFR 1.321(b).
The filing of a terminal disclaimer by itself is not a complete reply to a nonstatutory double patenting (NSDP) rejection. A complete reply requires that the terminal disclaimer be accompanied by a reply requesting reconsideration of the prior Office action. Even where the NSDP rejection is provisional the reply must be complete. See MPEP § 804, subsection I.B.1. For a reply to a non-final Office action, see 37 CFR 1.111(a). For a reply to final Office action, see 37 CFR 1.113(c). A request for reconsideration while not provided for in 37 CFR 1.113(c) may be filed after final for consideration. See MPEP §§ 706.07(e) and 714.13.
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Claims 1-24 are rejected on the ground of nonstatutory double patenting as being unpatentable over claims 1, 14, and 18 of Falath et al. (U.S. Patent No. 11,413,581 B2) in view of Khalifa et al. (U.S. Patent Application Publication No. 2020/0095138 A1).
Falath claim 1 recites a membrane distillation module comprising a vessel with an internal cavity; a hydrophobic membrane dividing the internal cavity into a feed zone and a distillate zone; a feed inlet fluidly connected to the feed zone; a feed outlet fluidly connected to the feed zone; a carrier gas outlet fluidly connected to the feed zone and further to the distillate zone and configured to bypass the membrane and transfer a portion of the carrier gas and feed stream vapor from the feed zone to the distillate zone and optionally further to an external condenser; and a distillate outlet fluidly connected to the distillate zone, wherein the carrier gas inlet enters the feed zone within the internal cavity, wherein the membrane is configured such that a portion of the feed stream vapor permeates through the hydrophobic membrane and is transferred to the distillate zone, and wherein the distillate zone is configured such that the vapor condenses in the distillate zone in the form of a distillate. Falath claim 14 further recites a vacuum pump in fluid communication with the distillate zone. Falath claim 18 further recites a method of concentrating and/or purifying a feed stream comprising contacting the feed stream, comprising a liquid and vapor, with the carrier gas in the feed zone of the module of claim 1, and obtaining a permeate containing water in the distillate zone and a concentrated feed stream from the feed stream outlet.
Khalifa discloses that membrane distillation devices may comprise two or more membrane distillation modules arranged in series and/or two or more membrane distillation modules arranged in parallel, and further illustrates multistage membrane distillation designs using parallel and series flow stage connections in Figs. 5A and 5B. Khalifa also discloses a feed water heater, a feed pump, a carrier gas circulation pump, a bubble column dehumidifier/condenser, a product outlet, hydrophobic microporous membranes, and the use of carrier gas to carry vapor from the membrane distillation module to the dehumidifier for condensation.
Regarding claim 1, Falath claims 1 and 14 in view of Khalifa render obvious a multistage vacuum membrane distillation (MS-VMD) system comprising a plurality of modules, wherein each module comprises: a feed chamber coupled to a feed line and a carrier gas line, wherein the feed line introduces a liquid feed into the feed chamber from a liquid feed tank, and wherein the carrier gas line introduces a carrier gas into the feed chamber; a vacuum chamber coupled to a vacuum line, wherein the vacuum line pulls a vacuum on the vacuum chamber; and a membrane separating the feed chamber from the vacuum chamber, wherein the membrane allows transportation of vapor from the feed chamber to the vacuum chamber while blocking liquid from moving from the feed chamber to the vacuum chamber. In particular, Falath claim 1 recites a membrane distillation module having a feed zone, a distillate zone (Line 4), and a hydrophobic membrane dividing the feed zone and distillate zone (Line 3-4), with a feed inlet, feed outlet, carrier gas inlet fluidly connected to the feed zone (lines 8-14), and carrier gas outlet fluidly connected to the feed zone and further to the distillate zone (Lines 15-16). Falath claim 14 further recites a vacuum pump in fluid communication with the distillate zone. Khalifa teaches applying membrane distillation modules in multistage arrangements, including two or more modules arranged in series and two or more modules arranged in parallel, as shown in Figs. 5A and 5B. It would have been obvious to one of ordinary skill in the art to implement the membrane distillation module claimed by Falath in a multistage arrangement as taught by Khalifa in order to increase system capacity and permeate productivity by using multiple membrane distillation stages in a predictable series and/or parallel configuration.
Regarding claim 2, Falath claims 1 and 14 in view of Khalifa render obvious the MS-VMD system of claim 1, further comprising a condenser fluidically coupled to the vacuum line, wherein the condenser condenses the vapor to form a purified distillate. Falath claim 1 recites that the carrier gas outlet may transfer carrier gas and feed stream vapor optionally further to an external condenser and further recites that the distillate zone is configured such that vapor condenses in the form of a distillate. Khalifa further teaches a bubble column dehumidifier/condenser downstream of the membrane distillation module for condensing vapor carried by the carrier gas into purified water/distillate.
Regarding claim 3, Falath claim 14 in view of Khalifa render obvious the MS-VMD system of claim 2, further comprising a vacuum pump fluidically coupled to the condenser, wherein the vacuum pump pulls the vacuum on the condenser and, through the condenser, the vacuum line. Falath claim 14 recites a vacuum pump in fluid communication with the distillate zone, and Khalifa teaches use of a gas circulation pump to withdraw vapor-containing carrier gas from the membrane distillation module and deliver it to the dehumidifier/condenser.
Regarding claim 4, Falath claim 1 in view of Khalifa render obvious the MS-VMD system of claim 2, further comprising a carrier gas outlet line fluidically coupling a carrier gas outlet on the feed chamber to the condenser. Falath claim 1 recites a carrier gas outlet fluidly connected to the feed zone and further to the distillate zone, configured to transfer a portion of the carrier gas and feed stream vapor from the feed zone to the distillate zone and optionally further to an external condenser. Khalifa further teaches delivery of humidified carrier gas to a bubble column dehumidifier/condenser.
Regarding claim 5, Falath claim 1 in view of Khalifa render obvious the MS-VMD system of claim 1, further comprising a carrier gas condenser fluidically coupled to a carrier gas outlet line that is fluidically coupled to a carrier gas outlet on the feed chamber. Falath claim 1 recites transfer of carrier gas and feed stream vapor from the feed zone optionally to an external condenser, and Khalifa teaches a bubble column dehumidifier/condenser for condensing vapor from carrier gas.
Regarding claim 6, Falath claim 1 in view of Khalifa render obvious the MS-VMD system of claim 1, wherein the plurality of modules are coupled in parallel to the feed line, the carrier gas line, and the vacuum line. Khalifa expressly teaches multistage membrane distillation designs in which two or more modules are arranged in parallel, as illustrated in Fig. 5A. It would have been obvious to arrange multiple Falath modules in parallel to increase throughput and production capacity.
Regarding claim 7, Falath claim 1 in view of Khalifa render obvious the MS-VMD system of claim 1, wherein the plurality of modules are fluidically coupling in series to the liquid feed, wherein a liquid input to the feed chamber of a first module in the series is fluidically coupled to the feed line, a liquid outlet of the feed chamber of a last module in the series is fluidically coupled to a feed return line, and each intervening module between the first module and the last module is fluidically coupled by line from a liquid outlet on the feed chamber of the intervening module to a liquid inlet on the feed chamber of the next module. Khalifa teaches multistage membrane distillation designs including series flow stage connections, as illustrated in Fig. 5B. It would have been obvious to arrange the liquid feed path through multiple Falath modules in series to increase distillation efficiency and to further process the feel liquid through sequential membrane distillation stages.
Regarding claim 8, Falath claims 1 and 14 in view of Khalifa render obvious the MS-VMD system of claim 1, wherein the plurality of modules are fluidically coupled in series to the vacuum, wherein a vacuum line of the vacuum chamber of a first module in the series is fluidically coupled to the vacuum line, a vacuum line of the vacuum chamber of a last module in the series is fluidically coupled to a line from a vacuum outlet on an intervening module, and each intervening module between the first module and the last module is fluidically coupled by a line from a vacuum outlet of the feed chamber of the intervening module to a vacuum inlet of the vacuum chamber of the next module. Falath claim 14 recites a vacuum pump in fluid communication with the distillate zone, and Khalifa teaches multistage membrane distillation modules arranged in series. It would have been obvious to fluidically connect the vacuum or permeate-side chambers of serially arranged modules to a common vacuum/condenser path in order to permit a single vacuum source and condenser/dehumidifier arrangement to withdraw vapor from a plurality of modules in a predictable multistage arrangement.
Regarding claim 9, Falath claim 1 in view of Khalifa render obvious the MS-VMD system of claim 1, wherein the plurality of modules are fluidically coupled in series to the carrier gas, wherein a carrier gas inlet the feed chamber of a first module in the series is fluidically coupled to the carrier gas line, a carrier gas outlet of the feed chamber of a last module in the series is fluidically coupled to a carrier gas outlet line, and each intervening module between the first module and the last module is fluidically coupled by line from the gas outlet of the feed chamber of the intervening module to a gas inlet of the feed chamber of the next module. Falath claim 1 recites a carrier gas inlet and a carrier gas outlet fluidly connected to the feed zone. Khalifa teaches serially arranged multistage membrane distillation modules. It would have been obvious to pass the carrier gas through the feed zones of multiple Falath modules in series to use the same carrier gas stream to enhance vapor removal and mass transfer through successive membrane distillation stages.
Regarding claim 10, Falath claim 1 in view of Khalifa render obvious the MS-VMD system of claim 1, comprising a heating element in a liquid feed tank, a heat exchanger on the feed line, or both. Khalifa teaches a feed water heater and heating of the feed water associated with the membrane distillation device. It would have been obvious to heat the feed liquid before introduction into the membrane distillation module because membrane distillation is thermally driven and heating increases vapor pressure and vapor flux.
Regarding claim 11, Falath claim 1 in view of Khalifa render obvious the MS-VMD system of claim 1, comprising a heating element disposed in a feed chamber of a module. Khalifa teaches heating saline water downstream of an/or within the water feed chamber, and Falath also recognizes heating of the feed stream in connection with membrane distillation operation. It would have been obvious to dispose a heating element in or at the feed chamber to maintain or increase feed temperature and thereby improve vapor generation.
Regarding claim 12, Falath claim 1 in view of Khalifa render obvious the MS-VMD system of claim 1, wherein the liquid feed comprises an aqueous solution. Khalifa is directed to desalination of saline water and therefore teaches an aqueous liquid feed.
Regarding claim 13, Falath claim 1 in view of Khalifa render obvious the MS-VMD system of claim 1, wherein the liquid feed comprises a liquid including a dissolved salt, a mixture of salts, a salt and an organic contaminant mixture, or a salt and an inorganic contaminant mixture, or any combinations thereof. Khalifa teaches desalination of saline water and salt-containing feed water, and Falath claim 17 recites that the feed stream includes ocean and/or saline seawater.
Regarding claim 14, Falath claim 1 in view of Khalifa render obvious the MS-VMD system of claim 1, wherein the liquid feed comprises seawater, industrial wastewater, brackish water, produced water, fruit juice, blood, milk, dye, hazardous-waste water, or a brine solution, or any combinations thereof. Falath claim 17 recites ocean and/or saline seawater, and Khalifa teaches desalination of saline water and seawater.
Regarding claim 15, Falath claim 1 in view of Khalifa render obvious the MS-VMD system of claim 1, wherein the membrane comprises a composite membrane, a nano-composite membrane, a hydrophobic membrane, an omniphobic membrane, a hydrophilic and hydrophobic composite dual layer membrane, a modified ceramic membrane, a porous ceramic membrane, a surface modified membrane, a polymer electrolyte membrane, a porous graphene membrane, or a polymeric membrane, or any combinations thereof. Falath claim 1 expressly recites a hydrophobic membrane, and Khalifa likewise teaches a hydrophobic microporous membrane.
Regarding claim 16, Falath claim 1 in view of Khalifa render obvious the MS-VMD system of claim 1, wherein the membrane comprises a reinforced hollow tube, a non-reinforced hollow tube, a spiral wound tube, a flat sheet, or a non-flat sheet, or any combinations thereof. Khalifa teaches that the membrane distillation device may take the form of a flat sheet channeled membrane distillation module as well as other membrane distillation module types, such as hollow fibers and spiral wound modules.
Regarding claim 17, Falath claim 1 in view of Khalifa render obvious the MS-VMD system of claim 1, wherein a contact angle of a droplet of the liquid feed on the membrane is greater than 90° (degrees). Falath claim 1 recites a hydrophobic membrane, and Khalifa teaches a hydrophobic microporous membrane. A hydrophobic membrane inherently has a water contact angle greater than 90 degrees or would at least have rendered such a contact angle obvious because hydrophobicity is the property used in membrane distillation to prevent liquid from passing through the membrane while allowing vapor transport.
Regarding claim 18, Falath claim 16 in view of Khalifa render obvious the MS-VMD system of claim 1, wherein the carrier gas comprises air, nitrogen, helium, argon, or carbon dioxide, or any combinations thereof. Falath claim 16 recites that the carrier gas includes air, and Khalifa further teaches carrier gases including air, H2, He, N2 Ar, or mixtures thereof.
Regarding claim 19, Falath claims 1, 14 and 18 in view of Khalifa render obvious a method for purifying a liquid using a multi-stage vacuum membrane distillation (MS-VMD) system, comprising: feeding a liquid to a feed chamber in each of a plurality of modules, wherein the liquid in the feed chamber is at a temperature of greater than about 50 °C; feeding a carrier gas through the liquid in the feed chamber of each of the plurality of modules to form humidified carrier gas; pulling a vacuum on a vacuum chamber in each of the plurality of modules through a vacuum line, wherein the vacuum chamber in each module is separated from the feed chamber in each module by a membrane, and wherein the membrane allows vapor to pass across the membrane while blocking liquid flow across the membrane; condensing purified liquid from the vacuum line; and condensing purified liquid from the humidified carrier gas. Falath claim 18 recites contacting a feed stream with carrier gas in the feed zone of the module of claim 1 and obtaining permeate containing water in the distillate zone and a concentrated feed stream from the feed stream outlet. Falath claim 14 recites a vacuum pump in fluid communication with the distillate zone. Khalifa teaches multistage membrane distillation modules, heating the feed water to membrane distillation operating temperatures, using carrier gas to carry vapor from the module, and condensing the vapor in a dehumidifier/condenser to collect purified water. It would have been obvious to perform the method of Falath using a multistage membrane distillation arrangement as taught by Khalifa to increase system output and improve permeate productivity.
Regarding claim 20, Falath claim 18 in view of Khalifa render obvious the MS-VMD system of claim 19, comprising heating the liquid before feeding the liquid to the feed chamber. Khalifa teaches a feed water heater and heating of the saline water before and/or during membrane distillation.
Regarding claim 21, Falath claim 18 in view of Khalifa render obvious the MS-VMD system of claim 19, comprising heating the liquid in the feed chamber. Khalifa teaches heating saline water downstream of and/or within the water feed chamber, and it would have been obvious to heat the liquid in the feed chamber to maintain vapor generation and improve distillation flux.
Regarding claim 22, Falath claim 18 in view of Khalifa render obvious the MS-VMD system of claim 19, comprising feeding the liquid to a feed chamber of a first module of the plurality of modules, then feeding the liquid exiting the feed chamber of the first module of the plurality of modules to a second module of the plurality of modules. Khalifa teaches multistage membrane distillation modules arranged in series, as shown in Fig. 5B, in which feed water passes through multiple stages.
Regarding claim 23, Falath claims 14 and 18 in view of Khalifa render obvious the MS-VMD system of claim 19, comprising pulling the vacuum on a vacuum chamber of a first module of the plurality of modules, then pulling the vacuum on a second module of the plurality of modules from the vacuum chamber of the first module of the plurality of modules. Falath claim 14 recites a vacuum pump in fluid communication with the distillate zone, and Khalifa teaches multistage membrane distillation modules arranged in series. It would have been obvious to connect the vacuum or permeate-side chambers of serially arranged modules to a common vacuum path so that the same vacuum source could withdraw vapor from plural modules in a compact and predictable multistage membrane distillation system.
Regarding claim 24, Falath claims 1 and 18 in view of Khalifa render obvious the MS-VMD system of claim 19, comprising feeding the carrier gas through a feed chamber of a first module of the plurality of modules, then feeding the carrier gas exiting the feed chamber of the first module of the plurality of modules to a feed chamber of a second module of the plurality of modules. Falath claim 1 recites a carrier gas inlet and carrier gas outlet fluidly connected to the feed zone, and Falath claim 18 recites contacting the feed stream with carrier gas in the feed zone. Khalifa teaches multistage membrane distillation modules arranged in series. It would have been obvious to pass carrier gas exiting the feed zone of a first Falath module to the feed zone of a second Falath module in a serial multistage arrangement to continue vapor pickup and mass-transfer enhancement across successive modules.
Accordingly, claims 1-24 are not patentably distinct from the claims of Falath et al. in view of Khalifa et al.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
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/W.A.G./ Examiner, Art Unit 1779
/Bobby Ramdhanie/ Supervisory Patent Examiner, Art Unit 1779
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