DETAILED ACTION
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 .
Claim Interpretation
The following is a quotation of 35 U.S.C. 112(f):
(f) Element in Claim for a Combination. – An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof.
The following is a quotation of pre-AIA 35 U.S.C. 112, sixth paragraph:
An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof.
This application includes one or more claim limitations that do not use the word “means,” but are nonetheless being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, because the claim limitation(s) uses a generic placeholder that is coupled with functional language without reciting sufficient structure to perform the recited function and the generic placeholder is not preceded by a structural modifier. Such claim limitation(s) is/are:
“a reliquefaction apparatus” in claim 1, line 4 is understood to be any art recognized liquefier (e.g., a heat exchanger).
Because this/these claim limitation(s) is/are being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, it/they is/are being interpreted to cover the corresponding structure described in the specification as performing the claimed function, and equivalents thereof.
If applicant does not intend to have this/these limitation(s) interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, applicant may: (1) amend the claim limitation(s) to avoid it/them being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph (e.g., by reciting sufficient structure to perform the claimed function); or (2) present a sufficient showing that the claim limitation(s) recite(s) sufficient structure to perform the claimed function so as to avoid it/them being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 1-3 and 11 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 1 recites "a train controller connected to the reliquefaction controller" for each train of the plurality of trains (i.e., a distinct train controller per train), and later recites that the at least one pressure controller is "connected to the train controller of each train" and configured to "output the operation signal toward the train controller" (emphasis added). Because "a train controller" was introduced as an element of each individual train, the later reference to "the train controller" (without repeating "of each train") lacks a clear antecedent basis. It cannot be determined whether the operation signal is directed to a single specific train controller, to all train controllers collectively, or to each train controller individually. Appropriate correction is required, e.g., ––output the operation signal toward the train controller of each train––.
Claim 1 recites that the reliquefaction controller is configured to control "reliquefaction amount" of the reliquefaction apparatus, and that in the second train the reliquefaction apparatus operates "at a fixed reliquefaction amount". The specification does not otherwise use the phrase "reliquefaction amount"; it instead describes a "reliquefaction capacity controller" regulating "reliquefaction capacity" (¶¶ 0010, 0049-0050) and quantifies operation in terms of "reliquefaction apparatus load," expressed as a percentage, in the worked example of ¶¶ 0059-0063 and Figs. 2-3. Because the claim does not state whether "reliquefaction amount" refers to this load percentage, a mass or volumetric flow rate of reliquefied boil-off gas, or some other quantity, and the term is not otherwise defined in the claim or reconciled with the specification's "capacity"/"load" terminology, the metes and bounds of "reliquefaction amount" are not clear. Applicant may wish to conform the claim terminology to that used in the specification (e.g., "reliquefaction load") or otherwise define the parameter in the claim.
Claims 2, 3, and 11 are also rejected under 35 U.S.C. 112(b) for being dependent upon a rejected claim.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claim 1 is rejected under 35 U.S.C. 103 as being unpatentable over Jung et al. (US 2014/0075943 A1) in view of Tezuka et al. (US 2019/0011179 A1) in view of Coward (US 8,783,061 B2) and further in view of Grassens et al. (US 9,695,834 B2).
In regard to claim 1, Jung teaches a boil-off gas reliquefaction system for a marine structure such as an LNG carrier (¶¶ 0002-0005), comprising:
a storage tank disposed in a ship and configured to store a liquefied gas (liquefied gas storage tank 11, ¶ 0082);
a vapor header through which the boil-off gas is discharged from the storage tank (BOG discharge line L1 through which BOG is discharged from storage tank 11 to maintain tank pressure at a suitable level, ¶ 0082); and
a reliquefaction apparatus configured to reliquefy boil-off gas generated from the liquefied gas (BOG compressed by BOG compression unit 13 is supplied to reliquefaction apparatus 20 and cooled/reliquefied through a refrigerant in cold box 21, ¶¶ 0083-0084).
Jung does not explicitly teach a reliquefaction controller configured to control reliquefaction amount of the reliquefaction apparatus, nor that the reliquefaction apparatus is configured to...return the reliquefied boil-off gas to the storage tank, nor at least one pressure controller...configured to generate an operation signal depending on a pressure at the vapor header.
However, Tezuka teaches a boil-off gas supply device comprising a storage tank (12) storing liquefied gas, wherein boil-off gas discharged from the storage tank is compressed by a first compression mechanism (C1) and a second compression mechanism (C2), and further comprising a return part (44) configured to re-liquefy the boil-off gas discharged from the second compression mechanism C2 and return the re-liquefied boil-off gas to the storage tank 12 (¶¶ 0027-0030). Tezuka further teaches a second pressure sensor (P2) configured to detect a pressure within the storage tank 12 (¶ 0042), and a return control part (52) that, based on the signal output from P2, controls the second drive source 48...so that the amount of gas compression by the second compression mechanism C2 may change (¶ 0044) — i.e., a controller that adjusts the amount of boil-off gas reliquefied by return part 44 depending on the pressure sensed at the storage tank. Tezuka additionally teaches a capacity control part (51) that, based on the signal output from P1 (discharge-side pressure) and P2, controls the first drive source 47 so that the amount of gas compressed by C1 may change, including reducing that amount when the storage-tank pressure P2 falls to or below a preset threshold ps2 (¶ 0047; Fig. 3, steps ST1-ST3), in order to prevent the storage tank pressure from becoming excessively low (¶ 0060).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Jung's reliquefaction apparatus to include a return-to-tank arrangement and an associated capacity/return controller responsive to storage-tank pressure, as taught by Tezuka, so that the reliquefaction controller adjusts the reliquefaction amount depending on the pressure at the vapor header (mapped to Tezuka's P2, which senses pressure at the storage tank from which the vapor header discharges BOG), in order to predictably regulate storage tank pressure while avoiding excessive or insufficient reliquefaction at varying BOG generation rates.
The modified Jung, as a single-train system, does not explicitly teach a plurality of trains, each comprising a reliquefaction apparatus, a reliquefaction controller, and a train controller connected to the reliquefaction controller and configured to control the reliquefaction controller, nor that at least one pressure controller is "connected to the train controller of each train" such that the train controller of each train is configured to (1) follow the pressure controller's operation signal or (2) operate independently of it.
However, Coward teaches a liquefied natural gas facility comprising a plurality of natural gas liquefaction trains 100a-100n, wherein "each liquefaction train could include multiple process controllers," e.g., train 100a includes "process controllers 206a, 208a, and 210a," train 100b includes "process controllers 206b, 208b, and 210b," and so on (col. 5, ll. 33-41), each set of per-train process controllers being distinct from and dedicated to its own train. Coward further teaches a control system 204 connected to the process controllers of every train and configured to coordinate them: "the control system 204 could generate control signals that are provided to the various controllers 206a-206n, 208a-208n, and 210a-210n, where the control signals control or alter how these controllers operate" (col. 5, ll. 51-56), and specifically that "optimized values 212a-212n are provided to the first process controllers 206a-206n of the trains 100a-100n. The first process controller in each train may set and control the mass flow rate of the...feed gas for that particular train" (col. 5, l. 57 – col. 6, l. 3) — i.e., a single, shared, higher-level controller connected to a train-level controller of each of a plurality of LNG liquefaction trains and outputting a control signal that the train-level controller uses to set that train's operation, directly corresponding to claim 1's "at least one pressure controller connected to the train controller of each train." Coward's second process controllers (208a-208n) "control the refrigerant loops in the trains" (col. 6, ll. 10-11), corresponding to the claimed reliquefaction controller of each train.
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the modified single-train system of Jung to include a plurality of trains, each having its own reliquefaction apparatus and reliquefaction controller (per the Tezuka modification), and a train-level process controller as taught by Coward, coordinated by a shared higher-level controller connected to the train controller of each train, in order to increase overall reliquefaction throughput beyond that of a single train, provide operational redundancy in the event a given train requires maintenance or experiences a fault, and enable centralized, facility-level coordination of reliquefaction capacity across multiple trains — the same motivations articulated by Coward itself for employing a plurality of trains coordinated by a shared control system (see Coward, col. 6, ll. 1-8, noting that the control system can send optimization solutions to individual trains as facility-wide demand changes). This is the predictable application of Coward's known multi-train LNG liquefaction control architecture to the modified single-train of Jung reliquefaction system, yielding the predictable result of a multi-train system in which each train retains pressure-responsive reliquefaction control at the train level.
The modified Jung does not explicitly teach that the train controller of each train is configured to (1) control the reliquefaction controller depending on the operation signal from the at least one pressure controller such that the reliquefaction controller adjusts the reliquefaction amount depending on the pressure at the vapor header or (2) operate independently of the at least one pressure controller, nor that, in one operation mode, the plurality of trains comprises a first train and a second train, wherein the first train's train controller adjusts reliquefaction amount depending on the pressure-based operation signal while the second train's train controller causes its reliquefaction apparatus to operate at a fixed reliquefaction amount, independent of the pressure controller. Jung in view of Coward teaches a control system 204 coordinates the trains toward a shared, facility-wide optimization objective, but does not explicitly show a given train's controller instead operating independently of that shared scheme at a fixed output.
However, Grassens teaches a compressor system comprising a plurality of compressor trains connected in parallel — "the example compressor system 100 includes two compressor trains 110, 150 in parallel" — wherein "control valve 116 is a primary control valve controlled by a primary controller," and "the performance controller of control valve 116 controls suction header pressure measured by PT 125 and is subject to parallel load sharing between compressor trains 110 and 150." Grassens further teaches that, as an alternative to this shared, pressure-based scheme, a train's secondary control mechanism can instead be operated via "a manual valve controller...to allow manual adjustment or intervention," with control logic (e.g., "a performance low signal select") selecting the manual controller's output in place of the automatically-computed one. A control mechanism held at such a manually-set position, rather than being driven by the shared pressure-based scheme, operates at a fixed output independent of that scheme — directly corresponding to claim 1's train controller (1) following the shared pressure-based signal, as with Grassens's primary controller, or (2) operating independently at a fixed, manually-set output, as via Grassens's manual valve controller alternative.
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to further modify the modified Jung multi-train system, per Grassens, such that a given train's controller is configured to either (1) follow the shared pressure-based operation signal, as with Grassens's primary controller, or (2) instead be held at a fixed, manually-set output independent of that signal, as via Grassens's manual valve controller alternative — and, specifically, to configure a first train per option (1) and a second train per option (2) in one operation mode — in order to allow an operator to hold one train at a fixed, dependable reliquefaction output for baseline production stability while the remaining, pressure-responsive train absorbs transient variation in storage tank pressure, consistent with Grassens's own rationale for providing a manual, independently-set alternative to the automatically-computed control scheme so as to allow manual adjustment or intervention.
Claims 2 and 11 are rejected under 35 U.S.C. 103 as being unpatentable over Jung, Tezuka, Coward, and Grassens as applied to claim 1 above, and further in view of Van Tassel (US 8,499,569 B2).
In regard to claim 2, the modified Jung teaches the boil-off gas reliquefaction system according to claim 1, further requires a first pressure transmitter configured to sense an absolute pressure of the boil-off gas at the vapor header and a second pressure transmitter configured to sense a gauge pressure of the boil-off gas at the vapor header. In this case, Jung as modified by Tezuka discloses a first pressure sensor (P1) at the discharge side of compression mechanism C1 and a second pressure sensor (P2) that detects pressure within the storage tank 12 (¶ 0042), but does not explicitly characterize P1 and P2 as sensing absolute pressure and gauge pressure, respectively.
However, Van Tassel discloses an LNG carrier boil-off gas management system employing an LNG cargo tank vapor space pressure transmitter (26) and a common boil-off gas pipeline header pressure transmitter (27), both feeding a Programmable Logic Controller (PLC 28) that reduces boil-off gas compressor flow when the cargo tank vapor space pressure, as monitored by transmitter 26, goes below a desired minimum pressure. This confirms that using two distinct pressure transmitters — one at the storage tank and one at a downstream header — to separately drive low-pressure protection and header-pressure regulation is a known measurement scheme in LNG carrier BOG management.
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the modified Jung by implementing P1 and P2 sensors as an absolute-pressure transmitter and a gauge-pressure transmitter, respectively, consistent with the multi-transmitter pressure-sensing scheme confirmed by Van Tassel, as this is the straightforward application of known pressure-sensing practices in the LNG carrier BOG management field to achieve the predictable result of accurate vapor-header/storage-tank pressure measurement for use by the train controllers of the modified Jung system.
In regard to claim 11, the modified Jung teaches the boil-off gas reliquefaction system according to claim 2, further requires a low pressure controller connected to the second pressure transmitter and connected to the reliquefaction controller of each train, the low pressure controller being configured to reduce the reliquefaction amount depending on a pressure value sensed by the second pressure transmitter. As set forth above, the modified Jung in view of Tezuka teaches a return control part 52 reduces the amount of gas compressed by C2 (and thus the amount of boil-off gas reaching return part 44 to be reliquefied) based on the pressure sensed by P2 (¶¶ 0044, 0049), and Tezuka's capacity control part 51 likewise decreases compression when P2 falls to or below threshold ps2, specifically to prevent the storage tank pressure from becoming excessively low (¶¶ 0047, 0060; Fig. 3, steps ST1-ST3).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention, to modify Jung by implementing Tezuka's low-pressure protection function as a dedicated low pressure controller, connected to the second (gauge) pressure transmitter and to the reliquefaction controller of each of Coward's trains, so that the storage tank is protected from excessive depressurization regardless of which train is, at a given time, operating under pressure-based control or at a fixed (base-load) reliquefaction amount. This is a predictable application of Tezuka's known low-pressure protection scheme across the plurality of trains taught by Coward.
Claim 3 is rejected under 35 U.S.C. 103 as being unpatentable over Jung, Tezuka, Coward, Grassens, and Van Tassel as applied to claim 2 above, and further in view of Lew (US 4,921,399).
In regard to claim 3, the modified Jung teaches the boil-off gas reliquefaction system according to claim 2, wherein Jung in view of Tezuka, as applied to claim 2 above, teaches a first pressure transmitter (Tezuka's P1, modified per Van Tassel to sense absolute pressure) and a second pressure transmitter (Tezuka's P2, modified per Van Tassel to sense gauge pressure), and further teaches that both pressure values are used, in combination, to determine the operation signal ultimately applied to adjust reliquefaction. Specifically, Tezuka's capacity control part 51 first evaluates the second pressure sensor P2 against a low-pressure threshold ps2 and, only if that condition is not met, evaluates the first pressure sensor P1 against a target pressure ps1, adjusting the first drive source 47 accordingly (¶ 0047; Fig. 3, steps ST1-ST6). Tezuka's return control part 52 separately adjusts the second drive source 48 based on P2 alone (¶ 0049).
Jung in view of Tezuka does not teach a first pressure controller and a second pressure controller as discrete components, each independently computing its own operation signal from only its own respective, single sensed pressure input, nor does it teach a selector configured to select one of the first operation signal and the second operation signal as a component separate from and downstream of those two controllers. Tezuka's capacity control part 51 instead uses a single, integrated block of branching logic that considers both P1 and P2 together (steps ST1-ST6) to arrive at one control action, rather than first generating two independently-computed operation signals and then selecting between them with a dedicated selector.
However, Lew teaches, in the closely analogous field of compressed-gas pipeline pressure/temperature control, a control architecture comprising discrete, independently-computed pressure controllers feeding a dedicated selector. Lew's first differential pressure controller (72) computes its own output based on its own sensed pressure inputs, and that output, \"signal 94[,] is provided from a differential pressure controller 72 as a first input signal to low select block 78\" (col. 5). Lew's second differential pressure controller (74) likewise independently computes its own output, and \"signal 106 is provided as a first input to high select block 80\" (col. 6). The outputs of high select block 80 and low select block 78 are combined so that \"control signal 120 is provided from low select block 78 to control valve 82, and control valve 82 is manipulated in response to the signal 120\" (col. 6) — i.e., two discrete, independently-computed controller output signals are fed into a dedicated selector block that chooses one signal to control a shared final control element. This "low select" and "high select" architecture is a known, named control-system component in the gas compression and pipeline control art for combining multiple independently-computed controller outputs into a single control signal.
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Jung by implementing Tezuka's integrated, branching-logic control of P1 and P2 as two discrete pressure controllers — a first pressure controller computing an operation signal from P1 alone and a second pressure controller computing an operation signal from P2 alone — coupled to a selector of the type taught by Lew, and to transmit the selected operation signal to the train controller of each of Coward's trains, in order to achieve Tezuka's already-desired result (prioritizing the low-pressure-protective signal over the target-pressure-regulating signal) using a known, named, and predictable control-architecture component (Lew's low select/high select selector) in place of Tezuka's integrated logic block, yielding no more than the predictable result of the same prioritized pressure-based control. KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398, 416 (2007); see also In re Fout, 675 F.2d 297, 301 (CCPA 1982) (a rearrangement of parts absent a new or unexpected functional relationship is not patentably distinct). This is further consistent with the multi-transmitter architecture confirmed by Van Tassel.
Response to Arguments
Applicant’s arguments with respect to the amended claims have been considered but are moot in view of the new ground(s) of rejection.
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.M/Examiner, Art Unit 3763
/FRANTZ F JULES/Supervisory Patent Examiner, Art Unit 3763
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