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 .
Specification
The disclosure is objected to because of the following informality:
Para. 9: “The barrier be openable…” appears it should read “The barrier is openable…” or similar.
Appropriate correction is required.
The lengthy specification has not been checked to the extent necessary to determine the presence of all possible minor errors. Applicant’s cooperation is requested in correcting any errors of which applicant may become aware in the specification.
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.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
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.
Claims 1-8 & 12-16 are rejected under 35 U.S.C. 103 as being unpatentable over Kupiszewski et al. (US 2015/0337730 A1; hereafter Kupiszewski) in view of Rohringer (EP 0 518 254 B1).
Note: EP 0 518 254 B1 was previously cited in the IDS received 12/24/2024, however, it is listed again in the PTO-892 with this action as an English translation is provided herewith. References to the specification of Rohringer (EP 0 518 254 B1) refer to this translation.
Regarding claim 1, Kupiszewski discloses (figs. 1-5) a double-wall pipe (conduit 54 in figs. 2 & 4; para. 28: “…at least a portion of the conduit 54…is insulated and configured for transporting a pressurized cryogenic liquid fuel. In some embodiments, at least a portion of the conduit 54 has a double wall construction…”; para. 35: “the…fuel lines running from the tank and boost pump to the engine pylons may have…single or double wall construction [and]…vacuum insulation or low thermal conductivity material insulation”) for an aircraft fuel system (50; see figs. 1 & 2).
The double-wall, vacuum insulated pipe of Kupiszewski as described above, configured for transporting pressurized cryogenic liquid fuel, would have been understood by a person having ordinary skill in the art to reasonably comprise:
an inner wall (i.e., the inner wall defining the flow conduit for liquid fuel) defining a first open end (e.g., an inlet end for connection to boost pump 52 and/or fuel tank 22), a second open end (e.g., an outlet end for connection to high pressure pump 58), and an inner region connecting the first open end to the second open end and via which a fuel is flowable through the double-wall pipe (i.e., the inner flow conduit configured for transporting the liquid fuel); and
an outer wall disposed at least in part around the inner wall to define an interspace (i.e., the vacuum insulation space surrounding the inner flow conduit), between the inner wall and the outer wall, that is fluidically isolated from the inner region (i.e., so as to maintain the vacuum).
Examination Note: while Kupiszewski shows the conduit 54 schematically by a single line, Kupiszewski depicts a similar double-wall vacuum insulation arrangement for the fuel tank (22) in fig. 3, having an inner wall (23) defining a liquid fuel space (12 / 112), and an outer wall (25) disposed around the inner wall to define a vacuum interspace (gap 26) between the inner and outer walls (see para. 53).
Moreover, as noted above, a person having ordinary skill in the art would have understood or otherwise readily inferred that the conduit 54, when provided as a double-wall, vacuum insulated conduit, would reasonably comprise the above arrangement of an inner and outer wall, with the inner wall defining a flow path between two open ends, the outer wall defining a vacuum insulation interspace between the inner and outer wall, especially considering that such double-wall, insulated fluid conduits are well-known in the art. See, e.g., US 2022/0090709 A1 to Eckols et at. (cited in 7/18/2024 IDS); US 2008/0314455 A1 to Jibb et al., DE 202016004781 U1 to Nexans, etc.. See MPEP § 2144.01.
Kupiszewski does not explicitly disclose the double-wall pipe to further comprise at least one barrier that is openable to create a passage that fluidically connects the interspace to the inner region, wherein the at least one barrier is configured to open when a pressure in the interspace is higher than a pressure in the inner region. However, when discussing the similar double-wall vacuum insulated fuel tank (22 / 122) of fig. 3, Kupiszewski suggests that a safety relief system (47) may be provided for the vacuum interspace (26), to prevent a “catastrophic overpressure pulse” which might otherwise occur in the event of an inner wall rupture, due to potential “flash vaporization” of fuel spilling into the vacuum interspace (see para. 71).
Rohringer teaches (figs. 1-4) a double-wall pipe comprising:
an inner wall (5) defining a first open end and a second open end (e.g., see fig. 2, top and bottom ends), and an inner region connecting the first open end to the second open end and via which a fluid is flowable through the double-wall pipe;
an outer wall (3; or 1 & 3) disposed at least in part around the inner wall to define an interspace (8; “leak detection gap”), between the inner wall and the outer wall, that is fluidically isolated from the inner region (i.e., when no leak is present); and
at least one barrier (18; “pressure relief valves”) that is openable to create a passage that fluidically connects the interspace to the inner region;
wherein the at least one barrier is configured to open when a pressure in the interspace is higher than a pressure in the inner region (pg. 3: “In the event of an overpressure present in the leak detection gap 8 with respect to the inside of the pipe, these allow the leakage gap contents to pass into the inside of the pipe and thus to establish a predetermined, permissible equilibrium state”).
Rohringer explains that, in the event of a leak of inner pipe 5, the interspace 8 can fill up. If inner tube 5 were then to be depressurized without relieving pressure in the interspace 8, a resulting external pressure could damage the inner tube 5 (pg. 3).
Rohringer later describes the barrier (18) as “unilaterally acting excess pressure safety means (18)…mounted in the inner pipe (5) which open from the leakage gap (8) into the inner pipe (5)” (claim 11).
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to modify the double-wall pipe of Kupiszewski to further comprise at least one barrier (e.g., unilaterally acting excess pressure relief valves) that is openable to create a passage that fluidically connects the interspace to the inner region, wherein the at least one barrier is configured to open when a pressure in the interspace is higher than a pressure in the inner region, in view of the teachings of Rohringer, to relieve an overpressure in the interspace resulting from a leak in the inner wall, allowing leaked fluid in the interspace to return to the inner region of the pipe to establish a predetermined permissible equilibrium state and preventing further damage to the inner wall which might otherwise occur due to overpressure in the interspace (i.e., as suggested by Rohringer), especially considering that Kupiszewski already suggests that pressure relief means should be provided to a vacuum interspace (i.e., of the fuel tank) to prevent a “catastrophic overpressure pulse” due to “flash vaporization” of fuel spilling into the vacuum interspace in the event of an inner wall rupture.
Regarding claim 2, the double-wall pipe of Kupiszewski, as modified above, reads on or otherwise renders obvious the additional limitation wherein the barrier (i.e., corresponding to pressure relief valve 18 of Rohringer) is configured to open when the pressure in the interspace is higher than the pressure in the inner region by an amount greater than a threshold pressure difference.
Rohringer describes the barrier as a “pressure relief valve” which relieves an “overpressure” in the interspace, and as a “unilaterally acting excess pressure safety means”. As would be understood by a person having ordinary skill in the art, such a barrier would be configured to open when the pressure in the interspace is some amount higher than the pressure in the inner region (i.e., an “overpressure” condition; or else fluid would likely backflow from the inner region to the interspace when the valve opens).
With respect to the “threshold pressure difference”, the claim does not require any specific threshold pressure difference, so the threshold pressure difference might be any value greater than 0. A person having ordinary skill in the art would have understood that an excess pressure relief valve as described by Rohringer would, in practice, have a minimum opening pressure, which is reasonably some pressure difference greater than zero, whereby the barrier is configured to open when the pressure in the interspace is higher than the pressure in the inner region by an amount greater than the threshold pressure difference (i.e. greater than the minimum opening pressure).
Examination Note: to promote compact prosecution, an alternative rejection for this claim is provided later in this action.
Regarding claim 3, the double-wall pipe of Kupiszewski, as modified above, reads on or otherwise renders obvious the additional limitation wherein the barrier is configured to remain closed when the pressure in the inner region is greater than the pressure in the interspace by an amount equal to or greater than the threshold pressure difference.
Rohringer describes the barrier as a “pressure relief valve”, “acting on one side” which relieves an “overpressure” present in the interspace, and as a “unilaterally acting excess pressure safety means”. Rohringer does not disclose the barrier as openable in response to a pressure in the inner region being greater than the pressure in the interspace.
As such, the “unilaterally acting” barrier is reasonably understood as being configured to remain closed when the pressure in the inner region is greater than the pressure in the interspace by an amount equal to or greater than the threshold pressure difference.
Examination Note: to promote compact prosecution, an alternative rejection for this claim is provided later in this action.
Regarding claim 4, the double-wall pipe of Kupiszewski, as modified above, reads on or otherwise renders obvious the additional limitation wherein the threshold pressure difference is lower than a burst pressure difference between the interspace and an outer region surrounding the outer wall.
Rohringer describes the barrier as operable to protect the inner wall from damage due to excess overpressure. Kupiszewski discloses providing a rupture / burst disk (46) to relieve overpressure within the inner region of the fuel tank, and a “similar parallel safety relief system” (47) for relieving overpressure in a vacuum interspace (paras. 70 & 71).
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention, when modifying the double-wall pipe of Kupiszewski in view of Rohringer as above, to select a threshold pressure difference (i.e., minimum barrier opening pressure) which is lower than a burst pressure difference between the interspace and an outer region surrounding the outer wall, as a matter of practical safety and/or as a matter of routine engineering design, since selecting a threshold pressure difference equal to or greater than a burst pressure difference between the interspace and outer region surrounding the wall would likely result in the outer wall rupturing before (or with) the barrier, releasing pressurized fluid to the exterior in an uncontrolled and potentially catastrophic fashion, which would otherwise render moot the presence of the barrier (pressure relief valve).
Regarding claims 5 & 6, with respect to the limitations wherein the at least one barrier comprises a rupturable barrier (claim 5) and wherein the at least one barrier comprises a rupture disc (claim 6), Rohringer does not provide details of the construction of the at least one barrier (18). However, Kupiszewski already discloses that a safety pressure release system (45) may comprise a rupture disk (46) which forms a portion of an inner wall (23), and explains that “The rupture disk 46 is a safety feature, designed using known methods, to blow out and release any high pressure gases in the event of an over pressure…” (para. 52).
If not already seen as such, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention, when modifying the double-wall pipe of Kupiszewski in view of Rohringer as above, to form the at least one barrier with a rupture disc (as in claim 6), whereby the at least one barrier comprises a rupturable barrier (as in claim 5), in view of the combined teachings of Kupiszewski and Rohringer, in order to provide for a relatively simple barrier which can reliably open to relieve an overpressure condition as required, without requiring an assembly of moving parts or electrical connections for actuation (i.e., as is otherwise well-known in the art, etc.).
Regarding claim 7, Kupiszewski discloses the additional limitation wherein a vacuum, or partial vacuum, is present in the interspace (see para. 35: “the…fuel lines running from the tank and boost pump to the engine pylons may have…single or double wall construction [and]…vacuum insulation or low thermal conductivity material insulation”).
Regarding claim 8, the combination of Kupiszewski and Rohringer renders obvious the additional limitations wherein the at least one barrier (i.e., corresponding to 18 of Rohringer) comprises a plurality of barriers, and wherein each of the plurality of barriers is openable to create a respective passage that fluidically connects the interspace to the inner region.
When describing the feature (18), Rohringer consistently utilizes plural language (pg. 3: “passage safeguards (pressure relief valves) 18 acting on one side…. In the event of an overpressure,… these allow the leakage gap contents to pass into the inside of the pipe…”), reasonably suggesting to a person having ordinary skill in the art that a plurality of such barriers may be provided (whereby each would be openable to create a respective passage that fluidically connects the interspace to the inner region at its respective location on the inner wall).
If not already seen as such, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention, when modifying the double-wall pipe of Kupiszewski in view of Rohringer as above, to include a plurality of such barriers, wherein each of the plurality of barriers is openable to create a respective passage that fluidically connects the interspace to the inner region, in view of the teachings of Rohringer, e.g., to enable the barriers to relieve pressure in various locations distributed along / around the pipe, and providing redundancy in the event that one or more barriers fail to open when required, etc., especially since Rohringer already appears to describe the use of a plurality of such barriers.
Furthermore, as set forth in MPEP § 2144.04(IV)(B), it has been held that, even where a prior art reference does not disclose a plurality of a part, mere duplication of parts has no patentable significance unless a new and unexpected result is produced [In re Harza, 274 F.2d 669, 124 USPQ 378 (CCPA 1960)].
Regarding claim 12, Kupiszewski further discloses (figs. 1-5) an aircraft fuel system (50; “fuel delivery system 50”) comprising:
a fuel tank (22 / 122) for storing fuel (12 or 112; “cryogenic liquid fuel”) for an engine (101) of an aircraft (5); and
a double-wall pipe (54) fluidically connected, or connectable, to the fuel tank (see figs. 2 & 4).
When the double-wall pipe (54) of Kupiszewski is modified in view of Rohringer as set forth for claim 1 above, the resulting aircraft fuel system would read on the additional limitation wherein the double-wall pipe is “the double-wall pipe of claim 1”.
Regarding claim 13, the aircraft fuel system of Kupiszewski, as modified above, reads on or otherwise renders obvious the additional limitation wherein the system comprises at least one pressure relief valve configured to fluidically connect the inner region to an atmosphere external to the double-wall pipe.
The inner (flow) region of the double-wall pipe (54) of Kupiszewski is fluidically connected to the fuel tank (22 / 122; via a boost pump 52 in figs. 2 & 4; fed by outflow system 30 in fig. 5), and Kupiszewski further discloses that the fuel tank is provided with a vent system (40), which may include a first pressure relief valve (39) to vent gaseous fuel to a number of locations, including “to atmosphere” (at V; see para. 80), and a second parallel safety relief system 45, comprising a burst disk (46) which can direct fuel “overboard” (para. 70).
In one aspect, as both the inner region of the double-walled pipe and the pressure relief valves (39 and/or 46) of Kupiszewski are each fluidically connected to the inner region of the fuel tank, the system of Kupiszewski may be seen to comprise least one pressure relief valve (i.e., 39 and/or 46) configured to fluidically connect the inner region of the double-wall pipe to an atmosphere external to the double-wall pipe, at least indirectly (i.e., fluidically connected through the fuel tank inner region).
Alternatively, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to modify the aircraft fuel system of Kupiszewski, by providing at least one pressure relief valve configured to fluidically connect the inner region to an atmosphere external to the double-wall pipe, in order to provide a safety relief system for the inner region of the double-wall pipe capable of mitigating an overpressure event in an analogous manner to that provided for the inner region of the fuel tank, particularly as the double-wall pipe, located downstream from a boost pump, may require operation and/or relief at different pressures relative to the fuel tank.
Regarding claim 14, the aircraft fuel system of Kupiszewski reads on or otherwise renders obvious the additional limitation wherein the system comprises liquid hydrogen fuel in the fuel tank.
Kupiszewski discloses that the fuel (12 / 112) in the fuel tank (22 / 122) is a “cryogenic liquid fuel” (see para. 27, 28, etc.) and, while the example primarily used in the disclosure is liquified natural gas (LNG), Kupiszewski explains that “other alternative cryogenic liquid fuels may also be used” (para. 40). In one instance, Kupiszewski explicitly lists “liquid hydrogen” as a “liquid fuel” along with LNG (para. 103). When using liquid hydrogen as the cryogenic fuel, the system of Kupiszewski would reasonably comprise liquid hydrogen in the fuel tank.
Examination note: to promote compact prosecution, it is noted that the use of liquid hydrogen as fuel in an aircraft fuel system is otherwise known in the art. See, e.g., US 2015/0336680 A1 to Schumacher et al (e.g., para. 1: “…an aircraft with a tank system, installed therein, for the cryogenic storage of hydrogen”; see also para. 4: “[t]he Airbus project “Cryoplane” provided for the use of liquid hydrogen as a fuel replacement for kerosene…”; etc.).
Regarding claim 15, Kupiszewski further discloses (fig. 1) an aircraft (5) comprising the double-wall pipe (54 in fig. 2; i.e., as part of fuel system 50).
When the double-wall pipe (54) is modified in view of Rohringer as already set forth for claim 1 above, the resulting aircraft would read on the additional limitation wherein the double-wall pipe is “the double-wall pipe of claim 1”.
Regarding claim 16, the combination of Kupiszewski and Rohringer further renders obvious an aircraft (5 of Kupiszewski) comprising the aircraft fuel system of claim 12 (see rejection of claim 12 above).
Claims 2-6 are alternatively rejected under 35 U.S.C. 103 as being unpatentable over Kupiszewski in view of Rohringer as applied to claim 1 above, and further in view of Wood et al. (US 4,301,938; hereafter Wood).
Regarding claims 2 & 3, to promote compact prosecution in the event that the double-wall pipe of Kupiszewski, as modified in view of Rohringer, is not seen as reading on or otherwise rendering obvious the limitations wherein the barrier (i.e., corresponding to pressure relief valve 18 of Rohringer) is configured to open when the pressure in the interspace is higher than the pressure in the inner region by an amount greater than a threshold pressure difference (as in claim 2) and/or wherein the barrier is configured to remain closed when the pressure in the inner region is greater than the pressure in the interspace by an amount equal to or greater than the threshold pressure difference (as in claim 3), the following additional teaching is provided.
Wood teaches (various embodiments in figs. 1-3, fig. 4 & figs. 5, 6, 8 & 9) a barrier (10, 100, 200, etc.) comprising a rupture disk / rupturable barrier (e.g.., 12 / 14), the barrier being openable to create a passage that fluidly connects a first space (400) to a second space (402) when a pressure in the second space (402) is higher than a pressure in the first space (400) by an amount greater than a threshold pressure difference (i.e., col. 4, lines 43-46; “a pre-determined pressure differential at which rupture of disk 12 will occur”; col. 6, lines 35-42: “a predetermined reverse mode rupture design pressure differential”).
Wood further teaches that, in some embodiments, the barrier may also be configured to open when the pressure in the first region is greater than the pressure in the second space by a second threshold pressure difference (i.e., a predetermined “normal mode pressure differential”), however, the “normal mode rupture pressure differential is higher than the reverse mode rupture pressure differential” (col. 7, lines 1-3; see also col. 7, lines 34-37; “the reverse mode pressure differential is … typically very low relative to the normal mode rupture pressure differential”).
If not already seen as such, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to modify the double-wall pipe of Kupiszewski (as otherwise modified above) such that the barrier is configured to open when the pressure in the interspace is higher than the pressure in the inner region by an amount greater than a threshold pressure difference (as in claim 2) and such that the barrier is configured to remain closed when the pressure in the inner region is greater than the pressure in the interspace by an amount equal to or greater than the threshold pressure difference (as in claim 3), in view of the teachings of Wood (or in view of the combined teachings of Wood and Rohringer), in order to provide for a controllable and predictable (via intentional design of a rupture disk used as the barrier, as taught by Wood) opening behavior when the interspace experiences an overpressure event, while ensuring the barrier remains closed under normal operating conditions, where the inner region is pressurized and the interspace is at vacuum.
Regarding claim 4, the double-wall pipe of Kupiszewski, as modified above, renders obvious the additional limitation wherein the threshold pressure difference is lower than a burst pressure difference between the interspace and an outer region surrounding the outer wall.
Rohringer describes the barrier as operable to protect the inner wall from damage due to overpressure. Kupiszewski discloses providing a rupture / burst disk (46) to relieve overpressure within the inner region of the fuel tank, and a similar safety system (47) for relieving overpressure in a vacuum interspace (paras. 70 & 71). Wood teaches the use of rupture disks as safety pressure relief devices configured to rupture at predetermined differential pressures.
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention, when modifying the double-wall pipe of Kupiszewski in view of Rohringer and Wood as above, to select a threshold pressure difference which is lower than a burst pressure difference between the interspace and an outer region surrounding the outer wall, as a matter of practical safety and/or as a matter of routine engineering design, since selecting a threshold pressure difference equal to or greater than a burst pressure difference between the interspace and outer region surrounding the wall would likely result in the outer wall rupturing before (or with) the barrier, releasing pressurized fluid to the exterior in an uncontrolled and potentially catastrophic fashion, which would otherwise render moot the presence of the barrier (pressure relief valve).
Regarding claims 5 & 6, the double-wall pipe of Kupiszewski, as modified in view of Wood above such that the barrier comprises a rupture disc, reads on or otherwise renders obvious the additional limitations wherein the at least one barrier comprises a rupturable barrier (claim 5) and wherein the at least one barrier comprises a rupture disc (claim 6).
Claims 9-11 are rejected under 35 U.S.C. 103 as being unpatentable over Kupiszewski in view of Rohringer as applied to claim 1 above, and further in view of Adler et al. (US 2014/0182706 A1; cited in applicant’s IDS received 12/24/2024; hereafter Adler).
Regarding claims 9-11, Kupiszewski and Rohringer do not specifically disclose the outer wall as defining a second, or a plurality, of interspaces fluidically isolated from the inner region and the first interspace.
Adler teaches (various embodiments in figs. 1-7) a double-wall pipe (10) comprising an inner wall (12) defining an inner region (see “flow”) for flow through the pipe, an outer wall (14) disposed around the inner wall to define an interspace (16) between the inner and outer walls that is fluidically isolated from the inner region (when no leaks are present and the spill return door 62 is closed; see fig. 1), and at least one barrier (i.e., spill return door 62) that is openable to create a passage that fluidically connects the interspace to the inner region (see fig. 2).
Adler further teaches providing a “spilled fluid barrier 20” / “annular bulkhead 22” that forms a seal between the inner and outer walls to define separate containment sections (24) along the pipeline, whereby fluid which leaks into one interspace is stopped by the bulkhead from continuing downstream into the adjacent interspace (see para. 87). Instead, upstream of each bulkhead, Adler provides a spill return door (62) to return spilled fluid from the interspace back to the inner region. As such, a leak is contained to the particular interspace and, by use of a sensor (26) in the interspace, the presence and location of a leak can be determined (see paras. 87-88).
Adler further explains that the “shunting and redirecting of the material back into the carrier pipe at a further location down the line promotes the same and continued transport of the material until the crew can effect the necessary repairs” (para. 104).
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to modify the double-wall pipe of Kupiszewski (as otherwise modified above) to provide a series of annular sealing bulkheads between the inner wall and outer wall, to form a plurality of interspaces disposed along the pipe, each fluidically isolated from the inner region and each other, wherein each of the interspaces is provided with at least one corresponding barrier that is openable to create a respective interspace passage that fluidically connects the respective interspace to the inner region, in view of the teachings of Adler, as the use of a known technique (i.e., dividing an annular interspace into a plurality of separate interspaces along a double-wall pipe, each with its own openable barrier to return spilled fluid to the inner region, as in Adler) to improve a similar device (i.e., the double wall pipe of Kupiszewski) in the same way (e.g., providing longitudinal isolation for leaks into the interspace, enabling a sensor network to easily detect the approximate location of a leak along the pipe, while also ensuring that a single leak does not compromise vacuum insulation along the entire pipe, etc.).
When modified as above, the double-wall pipe of Kupiszewski would read on the additional limitations wherein the interspace is a first interspace (i.e., any one of the plurality of interspaces), and the outer wall defines a second interspace (i.e., any one of the remaining interspaces), between the inner wall and the outer wall, that is fluidically isolated from the inner region and the first interspace (as in claim 9);
wherein the at least one barrier comprises at least one first-interspace barrier, the passage comprises a first-interspace passage that fluidically connects the first interspace to the inner region, and the double-wall pipe comprises at least one second-interspace barrier that is openable to create a second-interspace passage that fluidically connects the second interspace to the inner region (as in claim 10)(as explained above, each interspace would comprise at least one respective openable barrier; i.e., to relieve overpressure and return fluid to the inner region in the event of a leak into the respective interspace); and
wherein the outer wall defines one or more further interspaces (i.e., any one of the additional interspaces; other than the first and second interspaces), between the inner wall and the outer wall, wherein the, or each, further interspace is fluidically isolated from the inner region (when no leak is present in these further interspaces).
As a result, all of the limitations of claims 9-11 are met, or are otherwise rendered obvious.
Conclusion
The prior art made of record in the attached PTO-892 and not relied upon is considered pertinent to applicant's disclosure.
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/Richard K. Durden/Examiner, Art Unit 3753
/CRAIG M SCHNEIDER/Supervisory Patent Examiner, Art Unit 3753
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