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 .
Response to Amendment
The amendment filed June 09th, 2026 has been entered. Claims 1-20 remain pending in the application. Claims 11-20 remain withdrawn from consideration as being drawn to nonelected Group II. The amendment has raised other issues detailed below.
Specification
The disclosure is objected to because of the following informalities:
Abstract: “The systems is configured” should read “The systems are configured”
Appropriate correction is required.
Claim Objections
Claims 1-10 are objected to because of the following informalities:
Claim 1, lines 8-9: “tank volume exceed a relief pressure” should read “tank volume exceeds a relief pressure”
Claim 1, line 27: “the pressure” should read “the interior pressure”
Claims 2-3, 5-7 and 9-10 are also objected to by virtue of their dependency on claim 1.
Claim 4 is also objected to by virtue of its dependency on claim 3.
Claim 8 is also objected to by virtue of its dependency on claim 7.
Appropriate correction is required.
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.
Claim 6 is 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 6 recites the limitation "the second closed position" in line 2. There is insufficient
antecedent basis for this limitation in the claim. The Examiner recommends changing "the second closed position" in line 2 of claim 6 to “the closed position”. For purposes of examination, the Examiner will interpret “the second closed position" and “the closed position” to be the same position.
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.
Claims 1-2, 5, and 10 are rejected under 35 U.S.C. 103 as being unpatentable over Westenberger (US Patent No. 7,810,669), hereinafter Westenberger in view of Coers et al. (US Patent No. 5,511,383), hereinafter Coers.
Regarding claim 1, Westenberger discloses a liquid hydrogen tank assembly (Fig. 1, replaceable cartridge 700), comprising:
a liquid hydrogen fuel tank configured to contain hydrogen fuel in a liquid and a gaseous state, wherein the liquid hydrogen fuel tank has a tank volume (Fig. 1, tank 1, internal tank 112; Col. 4, lines 45-46 and 54-58, as well as a tank 1 for holding liquid hydrogen… thermal transfer from the environment at ambient temperature to the internal tank 112 is sufficient to bring a quantity of hydrogen from the liquid or partially liquefied state to a gaseous state which corresponds to the need of the consumer);
a passive pressure relief valve coupled to an interior of the liquid hydrogen fuel tank and configured to automatically move to a first open position when the interior pressure within the tank volume exceed a relief pressure threshold (Fig. 1, overpressure valve 6; Col. 7, lines 29-31, The valve 6 can for example be designed such that if a pressure p5 or a temperature T5 is exceeded, GH2 is conveyed to the exhaust pipe 55);
a plurality of sensors operatively coupled to the liquid hydrogen fuel tank and configured to measure conditions within the liquid hydrogen fuel tank, wherein the plurality of sensors include a first pressure sensor configured to determine the interior pressure within the tank volume and a second fill level sensor configured to obtain data to determine a fill level of the liquid hydrogen within the tank volume (Fig. 1, pressure gauge 31, thermometer 32, fill level sensor 37; Col. 5, lines 37-39 and 50-56, Reference numbers 30 and 31 designate pressure gauges which may for example have a drag indicator function. The pressure gauges indicate the pressure in the internal tank 112… Reference number 37 designates a fill level sensor in the internal tank 112, which interacts with a corresponding fill level indicator 38 arranged on the outside of the replaceable cartridge and on the outside displays the fill state of the liquid hydrogen in the internal tank 112. It is also possible for the fill level to be picked up by a consumer, by means of a coupling 39);
an active venting control system coupled to the liquid hydrogen fuel tank and to the plurality of sensors (Fig. 1, monitoring system 120, overpressure valves 4 and 5; Col. 6, lines 7-12, Reference number 120 designates a monitoring system which is connected to the respective couplings 39, 35, 34, 33 by electrical connections 1005, 1004, 1003, 1002, respectively, shown in FIG. 1. Furthermore, the monitoring system 120 can also be designed for controlling or checking a function or activation of the valves 2, 3, 4, 5, 6 and 14), the active venting control system comprising:
an active venting valve operatively communicating with the gaseous hydrogen located above the liquid hydrogen in the tank volume, the active venting valve being movable between a closed position an open position (Fig. 1, overpressure valves 4 and 5; Col. 5, lines 16-22, Furthermore, the removal pipe 7 is coupled to overpressure valves 4 and 5, which can relieve pressure to the surroundings if, for example, overpressure builds up in the internal tank 112. However, the overpressure valves 4 and 5 can also be arranged in conjunction with exhaust pipes 9 for removing exhaust gases from the internal tank 112. For example, gaseous hydrogen (GH2) can be an exhaust gas);
a controller coupled to the plurality of sensors and to the active venting valve the controller being: configured to use the information from the plurality of sensors to determine the pressure within the tank volume (Fig. 1, monitoring system 120; Col. 6, lines 7-30, Reference number 120 designates a monitoring system which is connected to the respective couplings 39, 35, 34, 33 by electrical connections 1005, 1004, 1003, 1002, respectively, shown in FIG. 1. Furthermore, the monitoring system 120 can also be designed for controlling or checking a function or activation of the valves 2, 3, 4, 5, 6 and 14. Moreover, the monitoring system 120 can be designed to control the supply of heat by way of the heat exchanger 13, and thus to control the quantity of gaseous hydrogen that is delivered. Preferably the monitoring system 120 is coupled to the fill level sensor 37 and the fill level indicator 38, to the temperature provider and indicator 32, the internal pressure provider and indicator 31, and a measuring system 30 (the pressure gauge) for monitoring the low pressure between the internal tank 112 and the external tank 114. The respective connections between the monitoring system 120 are shown in FIG. 1. For example, a connection between the respective sensors and valves and the monitoring system 120 can be implemented by means of corresponding electrical connections, 1002, 1003, 1004, and 1005. When the replaceable cartridge is connected to the consumer, these signals can be displayed or processed on board the consumer, for example on corresponding display devices in an aircraft).
However, Westenberger does not explicitly disclose the controller being: configured to use the information from the plurality of sensors to determine an effective fill level of the liquid hydrogen in the tank volume and the pressure within the tank volume, configured to move the active venting valve from the closed position to the second open position when the effective fill level exceeds an initial fill level threshold, and configured to move the active venting valve to the closed position when a secondary threshold is reached after reaching the initial fill level threshold, wherein the secondary threshold is different than the initial fill level threshold.
Coers teaches the controller being: configured to use the information from the plurality of sensors to determine an effective fill level of the liquid hydrogen in the tank volume and the pressure within the tank volume, configured to move the active venting valve from the closed position to the second open position when the effective fill level exceeds an initial fill level threshold, and configured to move the active venting valve to the closed position when a secondary threshold is reached after reaching the initial fill level threshold, wherein the secondary threshold is different than the initial fill level threshold (Col. 4-5, lines 37-67 and 1-14, Vessel 10 is filled with cold liquid, as described above, to the first level 20. After filling, heat gain by the cold liquid causes it to expand to a higher predetermined level 30. Conduit 34 is maintained within the evacuated space 54 to the extent possible to minimize heat leak into vessel 10 and cold liquid drains into conduit 34 as described above. Sensor 36 is cooled by the cold liquid from conduit 34 and an electrical signal or gas pressure activates vapor discharge valve 40 to release pressurized vapor or, when desired, to drain valve 42 to release liquid. In the FIG. 2 embodiment, vapor vent valve 40 is in vapor communication with the vessel vapor space 32 via conduit 58 which is fed through the evacuated space 54 to minimize heat leak to vessel 10. This arrangement permits pressure relief valve 28 to communicate with conduit 58 via conduit 60 upstream of vapor discharge valve 40 to provide a failsafe upon release should sensor 36 or vapor discharge valve 40 fail to perform as intended. With either of the above described embodiments, vessel 10 can be used to store a cold liquid such as liquefied natural gas (LNG) or liquid methane. Cold liquid is initially filled to the first level 20 to provide a vapor space (sometimes referred to as ullage) that permits some expansion of the cold liquid but not as much as would be required if no means for maintaining the level of liquid were used. This results in a greater effective vessel volume available for storage of cold liquid. Nevertheless, some vapor space will be needed and some expansion of the cold liquid will result due to heat leak into the vessel. The expansion is tolerated until it reaches the predetermined higher level 30 where sensor 36 is in thermal communication either directly or through conduit 34. When cold liquid cools sensor 36, vapor vent valve 40 is activated to release pressurized vapor. Sensor 36 may also activate a liquid discharge valve 42 for controlled release of cold liquid. Regardless, pressure relief valve 28 should not be contacted by cold liquid. Once enough vapor and/or liquid have been released, the temperature will stabilize, and the level of cold liquid will remain at or just below the predetermined higher level. When cold liquid is removed from tank 10 the cold liquid that is in thermal communication with sensor 36 will warm and evaporate and no further signal will be generated to open vent valve 40 or liquid discharge valve 42).
Therefore, it would have been obvious before the effective filing date of the claimed invention to reprogram the controller of Westenberger of claim 1 to be configured to use the information from the plurality of sensors to determine an effective fill level of the liquid hydrogen in the tank volume and the pressure within the tank volume, configured to move the active venting valve from the closed position to the second open position when the effective fill level exceeds an initial fill level threshold, and configured to move the active venting valve to the closed position when a secondary threshold is reached after reaching the initial fill level threshold, wherein the secondary threshold is different than the initial fill level threshold as taught by Coers. One of ordinary skill in the art would have been motivated to make this modification to provide a greater effective vessel volume available for storage of cold liquid (Coers, Col. 4, lines 62-64).
Regarding claim 2, Westenberger as modified discloses the assembly of claim 1 (see the combination of references used in the rejection of claim 1 above) wherein the plurality of sensors are operatively coupled to the hydrogen fuel tank and are configured to measure within the tank volume at least one of a liquid hydrogen temperature and a tank pressure wherein the liquid temperature is a temperature reading of the liquid hydrogen, wherein the tank pressure a pressure reading of the interior pressure within the hydrogen fuel tank (Westenberger, Fig. 1, pressure gauge 31, thermometer 32; Col. 5, lines 37-49, Reference numbers 30 and 31 designate pressure gauges which may for example have a drag indicator function. The pressure gauges indicate the pressure in the internal tank 112. Reference number 32 designates a thermometer which may also have a drag indicator function, and which indicates a temperature in the internal tank 112 of the replaceable cartridge. In conjunction with the pressure gauges 30 and 31 and the thermometer 32, couplings 33, 34 and 35 are provided which are used to connect the cartridge to the consumer. These couplings make it possible for the consumer for example to register pressure or a pressure development in the internal tank of the replaceable cartridge, or to register a temperature in the internal tank 112).
Regarding claim 5, Westenberger as modified discloses the assembly of claim 1 (see the combination of references used in the rejection of claim 1 above) wherein the secondary threshold is a secondary fill level threshold that is less than the initial fill level threshold, and the controller is configured to move the active venting valve to the second closed position when the effective fill level reaches the secondary fill level threshold (Coers, Col. 5, lines 8-14, Once enough vapor and/or liquid have been released, the temperature will stabilize, and the level of cold liquid will remain at or just below the predetermined higher level. When cold liquid is removed from tank 10 the cold liquid that is in thermal communication with sensor 36 will warm and evaporate and no further signal will be generated to open vent valve 40 or liquid discharge valve 42). Further, the limitations of claim 5 are the result of the modification of references used in the rejection of claim 1 above.
Regarding claim 10, Westenberger as modified discloses the assembly of claim 1 (see the combination of references used in the rejection of claim 1 above) wherein the active venting valve is coupled to a catalyst, wherein the catalyst is configured to convert gaseous hydrogen released through the active venting valve into an exhaust containing water (Fig. 2, recombination unit 54; Col. 6, lines 52-55, By way of coupling 51, valve 5 can be connected to a recombination unit 54 which in turn is connected to an exhaust pipe 56 by way of which, for example, water can be conveyed).
Claims 3-4 are rejected under 35 U.S.C. 103 as being unpatentable over Westenberger as modified by Coers as applied to claim 1 above, and further in view of Gordon (US Patent No. 9,939,298), hereinafter Gordon.
Regarding claim 3, Westenberger as modified discloses the assembly of claim 1 (see the combination of references used in the rejection of claim 1 above).
However, Westenberger as modified does not disclose wherein the controller is configured to calculate a hydrogen vapor density based on a vapor temperature and a tank pressure, a liquid density based on a liquid temperature and the tank pressure, an average density based on a hydrogen mass and the tank volume, and an effective fill level calculated by the controller is based on the hydrogen vapor density, the liquid density, and the average density.
Gordon teaches wherein the controller is configured to calculate a hydrogen vapor density based on a vapor temperature and a tank pressure, a liquid density based on a liquid temperature and the tank pressure, an average density based on a hydrogen mass and the tank volume, and an effective fill level calculated by the controller is based on the hydrogen vapor density, the liquid density, and the average density (Col. 5-6, lines 38-48, 59-67, and 1-3, GUI 173 can allow a user to program a set of inputs that an include a storage tank 110 volume, a pressure relief set point, an orifice size for PRD 150, gas 111 density, and reseat point for PRD 150. The pressure relief set point can be based on the maximum allowable operating pressure of the system (i.e., storage tank, piping, components, etc.) According to various other embodiments, controller 150 can be configured to detect at least one or more of the set of inputs directly from the devices using smart instrumentation hardware configured to communicate using a form of field bus communication… The set of input variables can include storage tank 110 volume, pressure relief set point, PRD 150 orifice size, gas 111 density, and reseat point for PRD 150. Based on these inputs a pressure relief device release rate for PRD 150 can be calculated. Accordingly, if the effective orifice size of PRD 150 is greater than the maximum effective orifice size of regulating device 140, then dP/dt during normal operation (i.e., flow through regulating device 140) will be smaller than release rate during a PRD 150 release. This can allow the calculated release rate for PRD 150 to be used as an alarm or set point in control logic to detect if PRD 150 has been activated; Col. 7-8, lines 10-19, 26-34, 46-48, 55-61, and 1-7, Density of Hydrogen Gas: Hydrogen does not behave in the ideal gas realm, therefore the real gas density needs to be calculated from the equation of state, see, e.g., "Revised Standardized Equation of State for Hydrogen Gas Densities for Fuel Consumption Applications," E.W. Lemmon, M. L. Huber, J. W. Leach-man, J. Res. Natl. Inst. Stand. Technol. 113, 341-350 (2008). This equation utilizes the ideal gas equation and corrects for real gas by calculating the compressibility factor for a given pressure and temperature condition…For equation 2 above, T is the temperature of the gas in the storage vessel in Kelvin and P is the pressure of the gas in the vessels in MPA. For analysis purpose temperature can be assumed to be the ambient temperature or worst case conditions for a pressure relief device release (i.e., lowest operating temperature). The constants ai, Bi, and Ci are defined in the (Lemmon, Huber, & Leachman, 2008) and are shown below in Table 3 below… Once the compressibility factor is determined, the density can be calculated using the ideal gas law, shown below as equation 3... For equation 3, P is the pressure of the gas inside the vessel in MPa, Z is the compressibility factor calculated from equation 2, R is the universal gas constant and T is the temperature of the gas inside the vessel in degrees Kelvin. Equation 4 shown below can be used to convert the molar based density from equation 3 to a mass based density (kilograms per cubic meter)… For equation 4, the molecular weight of hydrogen is equal to 2.01588 grams per mole. Initial Vessel Mass: Equation 5 shown below can be used to determine initial mass. Equation 5 provides the total mass of the hydrogen gas in the vessel at initial conditions in kilograms).
Therefore, it would have been obvious before the effective filing date of the claimed invention to reprogram the controller of Westenberger as modified wherein the controller is configured to calculate a hydrogen vapor density based on a vapor temperature and a tank pressure, a liquid density based on a liquid temperature and the tank pressure, an average density based on a hydrogen mass and the tank volume, and an effective fill level calculated by the controller is based on the hydrogen vapor density, the liquid density, and the average density as taught by Gordon. One of ordinary skill in the art would have been motivated to make this modification to allow the control system to react appropriately in the event of a PRY activation caused by over-pressurization to improve overall system safety and efficiency (Gordon, Col. 1, lines 45-46).
Regarding claim 4, Westenberger as modified discloses the assembly of claim 1 (see the combination of references used in the rejection of claim 1 above) wherein the controller is configured to compare the calculated effective fill level to the initial fill level threshold (Coers, Col. 4-5, lines 56-67 and lines 1-14, With either of the above described embodiments, vessel 10 can be used to store a cold liquid such as liquefied natural gas (LNG) or liquid methane. Cold liquid is initially filled to the first level 20 to provide a vapor space (sometimes referred to as ullage) that permits some expansion of the cold liquid but not as much as would be required if no means for maintaining the level of liquid were used. This results in a greater effective vessel volume available for storage of cold liquid. Nevertheless, some vapor space will be needed and some expansion of the cold liquid will result due to heat leak into the vessel. The expansion is tolerated until it reaches the predetermined higher level 30 where sensor 36 is in thermal communication either directly or through conduit 34. When cold liquid cools sensor 36, vapor vent valve 40 is activated to release pressurized vapor. Sensor 36 may also activate a liquid discharge valve 42 for controlled release of cold liquid. Regardless, pressure relief valve 28 should not be contacted by cold liquid. Once enough vapor and/or liquid have been released, the temperature will stabilize, and the level of cold liquid will remain at or just below the predetermined higher level. When cold liquid is removed from tank 10 the cold liquid that is in thermal communication with sensor 36 will warm and evaporate and no further signal will be generated to open vent valve 40 or liquid discharge valve 42). Further, the limitations of claim 4 are the result of the modification of references used in the rejection of claim 3 above.
Claim 6 is rejected under 35 U.S.C. 103 as being unpatentable over Westenberger as modified by Coers as applied to claim 1 above, and further in view of Tsuru et al. (US 20250319985), hereinafter Tsuru.
Regarding claim 6, Westenberger as modified discloses the assembly of claim 1 (see the combination of references used in the rejection of claim 1 above).
However, Westenberger as modified does not disclose wherein the controller is configured to move the active venting valve from the open position to the second closed position after a predetermined time period after moving the active venting valve to the open position.
Tsuru teaches the control of pressure control valve to be at least partially controlled in relation to a time period between switching the valve between open and closed states (Fig. 4, When the line pressure drops below the closing operation pressure value PL2, the second regulating valve 36 is closed. The time at which the second regulating valve 36 is closed is time t2. After time t2, the introduction of the vaporized gas of the liquid hydrogen LH continues, and thus the tank internal pressure gradually rises. Further, when the second regulating valve 36 is closed, the line pressure also gradually rises. When the line pressure eventually exceeds the closing operation pressure value PUZ, the second regulating valve 36 is opened. The time at which the second regulating valve 36 is closed is time t3).
Westenberger as modified fails to teach wherein the controller is configured to move the active venting valve from the open position to the second closed position after a predetermined time period after moving the active venting valve to the open position, however Tsuru teaches that it is a known method in the art of liquid hydrogen tank pressure control to include the control of pressure control valve to be at least partially controlled in relation to a time period between switching the valve between open and closed states. This is strong evidence that modifying Westenberger as modified as claimed would produce predictable results (i.e. preventing over pressurization of the liquid hydrogen tank to improve overall system safety). Accordingly, it would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to modify Westenberger as modified by Tsuru and arrive at the claimed invention since all claimed elements were known in the art and one having ordinary skill in the art could have combined the elements as claimed by known methods with no changes in their respective functions and the combination would have yielded the predictable result of preventing over pressurization of the liquid hydrogen tank to improve overall system safety.
Claims 7-9 are rejected under 35 U.S.C. 103 as being unpatentable over Westenberger as modified by Coers as applied to claim 1 above, and further in view of Rebernik et al. (US 20250043915), hereinafter Rebernik.
Regarding claim 7, Westenberger as modified discloses the assembly of claim 1 (see the combination of references used in the rejection of claim 1 above).
However, Westenberger as modified does not disclose wherein the hydrogen fuel tank and the active venting control system configured to enable the hydrogen fuel tank to be filled with liquid hydrogen to an initial mass of approximately 195 kg and an initial fill level in the range of approximately 90% - 95% of the tank's interior volume, and to allow for storage of approximately 200 hours with retention of about 158 kg of hydrogen in the tank after the storage after active venting during the storage.
Rebernik teaches hold time for a cryogenic fluid within a tank to be based on the thermodynamic characteristics of the fluid within the tank. These teachings indicate the hold time of a cryogenic fluid (including a change in amount of the cryogenic fluid from an initial fill level over a period of stage time) to be a result effective variable in that changing the thermodynamic characteristics within the tank changes the hold time of the cryogenic fluid (Pg. 8, paragraph 72, However, the primary factor for calculating the hold time is a determination of the current thermodynamic state of the cryogenic fluid, as it will have the greatest impact on the hold time. For this purpose, for example, the current mass of the cryogenic fluid in the cryogenic container 2 is determined, which, in the simplest case, can be determined directly by weighing the cryogenic container or by evaluating mechanical stresses on the cryogenic container 2. However, the mass of the cryogenic fluid can also be determined from a combination of at least two thermodynamic measured values, e.g., the pressure, the temperature, the density and/or the height of the liquid level (if the cryogenic fluid is present as a two-phase mixture). There upon, the hold time can be calculated from the mass, in combination with a measured value relevant to the thermodynamic state, in particular the pressure or the temperature. However, the hold time could generally also be determined without the intermediate step of calculating or, respectively, determining the mass, for example, if at least two or at least three of the aforementioned thermodynamic measured values are provided to a computing unit or a filling station. However, current status data are also preferably sent to the filling station, e.g., a current pressure, fill level, temperature, etc., during refuelling, whereby the accuracy of the calculation can be increased. In summary, the period of time after which the pressure in the cryogenic vessel 2 will reach a predefined threshold value can be determined based on the knowledge about the current thermodynamic state). Therefore, it would have been obvious to one having ordinary skill in the art at the time of the invention to modify the assembly of Westenberger as modified to enable the hydrogen fuel tank to be filled with liquid hydrogen to an initial mass of approximately 195 kg and an initial fill level in the range of approximately 90% - 95% of the tank's interior volume, and to allow for storage of approximately 200 hours with retention of about 158 kg of hydrogen in the tank after the storage after active venting during the storage as a matter of routine optimization since it has been held that “where the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955).
Regarding claim 8, Westenberger as modified discloses the assembly of claim 7 (see the combination of references used in the rejection of claim 7 above).
However, Westenberger as modified does not disclose wherein the initial fill level is approximately of 92% of the tank's interior volume.
Westenberger as modified teaches the claimed invention except for wherein the initial fill level is approximately of 92% of the tank's interior volume. It would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to include wherein the initial fill level is approximately of 92% of the tank's interior volume, since it has been held that where the general conditions of a claim are disclosed in the prior art, discovering the optimum or workable ranges [ or optimum value ] involves only routine skill in the art. In re Aller, 105 USPQ 233. MPEP 2144.05-II-A.
Furthermore, since applicants have not disclosed that these modifications solve any stated problem or are for any particular purpose and it appears that the device would perform equally well with either designs, these modifications are a matter of design choice. Absent a teaching as to criticality of wherein the initial fill level is approximately of 92% of the tank's interior volume, this particular arrangement is deemed to have been known by those skilled in the art since the instant specification and evidence of record fail to attribute any significance (novel or unexpected results) to a particular arrangement. In re Kuhle, 526 F.2d 553,555,188 USPQ 7, 9 (CCPA 1975). MPEP 2144.05.
Regarding claim 9, Westenberger as modified discloses the assembly of claim 1 (see the combination of references used in the rejection of claim 1 above).
However, Westenberger as modified does not disclose wherein a predetermined fill level is based on a saturation curve of hydrogen.
Rebernik teaches wherein a predetermined fill level is based on a saturation curve of hydrogen (Pg. 8, paragraph 72, However, the primary factor for calculating the hold time is a determination of the current thermodynamic state of the cryogenic fluid, as it will have the greatest impact on the hold time. For this purpose, for example, the current mass of the cryogenic fluid in the cryogenic container 2 is determined, which, in the simplest case, can be determined directly by weighing the cryogenic container or by evaluating mechanical stresses on the cryogenic container 2. However, the mass of the cryogenic fluid can also be determined from a combination of at least two thermodynamic measured values, e.g., the pressure, the temperature, the density and/or the height of the liquid level (if the cryogenic fluid is present as a two-phase mixture). There upon, the hold time can be calculated from the mass, in combination with a measured value relevant to the thermodynamic state, in particular the pressure or the temperature. However, the hold time could generally also be determined without the intermediate step of calculating or, respectively, determining the mass, for example, if at least two or at least three of the aforementioned thermodynamic measured values are provided to a computing unit or a filling station. However, current status data are also preferably sent to the filling station, e.g., a current pressure, fill level, temperature, etc., during refuelling, whereby the accuracy of the calculation can be increased. In summary, the period of time after which the pressure in the cryogenic vessel 2 will reach a predefined threshold value can be determined based on the knowledge about the current thermodynamic state; Further, the teachings of Rebernik at least imply the predetermined fill level is based on a saturation curve of hydrogen as the both pressure and temperature of the cryogenic fluid, which define a fluid’s saturation curve, are included as thermodynamic characteristics used to determine filling and hold time of a cryogenic fluid within a tank since it has been held in considering the disclosure of a reference, it is proper to take into account not only specific teachings of the reference but also the inferences which one skilled in the art would reasonably be expected to draw therefrom (MPEP 2144.01)).
Westenberger as modified fails to teach disclose wherein the predetermined fill level is based on a saturation curve of hydrogen, however Rebernik teaches that it is a known method in the art of cryogenic tank filling to include wherein the predetermined fill level is based on a saturation curve of hydrogen. This is strong evidence that modifying Westenberger as modified as claimed would produce predictable results (i.e. to improve the hold time of the liquid hydrogen within the liquid hydrogen fuel tank (Rebernik, Pg. 9, paragraph 75)). Accordingly, it would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to modify Westenberger as modified by Rebernik and arrive at the claimed invention since all claimed elements were known in the art and one having ordinary skill in the art could have combined the elements as claimed by known methods with no changes in their respective functions and the combination would have yielded the predictable result of to improve the hold time of the liquid hydrogen within the liquid hydrogen fuel tank (Rebernik, Pg. 9, paragraph 75).
Response to Arguments
Applicant's arguments filed June 09th, 2026 have been fully considered but they are not persuasive.
Applicant argues on Pg. 16-18 (as numbered by the Applicant) of the Remarks, “As a preliminary comment, Applicant respectfully draws the Examiner's attention to a significant inconsistency between the present examination and the International Search Report ("ISR") established for the directly related PCT application PCT/US23/85082, filed December 20, 2023, and claiming the same priority date of July 21, 2023 (U.S. Provisional Application No. 63/515,059). The ISR for PCT/US23/85082 was established by the United States Patent and Trademark Office acting as International Searching Authority (ISA/US) and was completed on March 11, 2024. The ISA/US cited no document in category "X" and no document in category "Y" against any of claims 1-20 of the international application. The claims of PCT application PCT /US23/85082 are substantially identical to the present claims, covering the same inventive concept of an active venting control system employing a controller configured to open and close an active venting valve based on an effective fill level computed from sensor data, operating between an initial fill level threshold and a distinct secondary threshold. The ISA/US, which is the same Office now examining the present application, found no prior art that anticipated or rendered obvious the claimed invention. Applicant respectfully submits that this inconsistency warrants serious consideration. While Applicant acknowledges that the ISR does not bind the Examiner, the positive outcome of the international search constitutes meaningful evidence that the present claims define a patentable invention.”
However, this argument is not persuasive as the findings of the ISA are non-binding to the Examiner per MPEP 1893.03(e) - "When an international preliminary examination is performed by an International Preliminary Examining Authority (IPEA), an international preliminary examination report (IPER) is prepared on Form PCT/IPEA/409 by the IPEA and sent to the elected Offices. This report reflects the IPEA’s non-binding opinion regarding lack of unity of invention, novelty, inventive step and industrial applicability." See the rejection of claim 1 above.
Applicant argues on Pg. 18-19 (as numbered by the Applicant) of the Remarks, “As to the rejection of claim 1, The Examiner concedes that Westenberger does not disclose the core of the disputed limitation: a controller configured to (i) determine an effective fill level, (ii) open the active venting valve when the effective fill level exceeds an initial fill level threshold, and (iii) close the active venting valve when a secondary threshold (which is different from the initial fill level threshold) is reached. The Examiner relies on Coers to supply this missing teaching. Applicant respectfully submits that Coers does not teach this limitation, for the reasons set forth below. The Examiner contends that Coers teaches a system with an initial fill level (first level 20) and "a secondary closing threshold (the ""predetermined higher level 30""), thereby teaching the distinct initial and secondary thresholds of claim 1. Applicant respectfully disagrees with this characterization of Coers. A careful reading of Coers reveals a system of an entirely different nature." In Coers, the vessel is initially filled to first level 20, which is simply the initial filling level set by the operator (Col. 3, lines 5-25). First level 20 is not a control threshold. It is a filling target established manually before the system's automatic control mechanism is even activated.”
In response to applicant's argument that the references fail to show certain features of the invention, it is noted that the features upon which applicant relies (i.e., the initial fill level being a controlled threshold) are not recited in the rejected claim(s). Although the claims are interpreted in light of the specification, limitations from the specification are not read into the claims. See In re Van Geuns, 988 F.2d 1181, 26 USPQ2d 1057 (Fed. Cir. 1993). More specifically, claim 1 only requires the existence of an initial fill level threshold and control decisions to be made based on exceeding the initial fill level threshold, claim 1 does not require the controller to control the initial fill level threshold. Further Coers discloses the filling can be automatically controlled (Alternatively, a differential pressure level switch (not shown) may be used to detect when the liquid level reaches elevation 20 and engage a valve operator to close valve 24 (Col. 3, lines 20-23)). See the rejection of claim 1 above.
Applicant argues on Pg. 19-21 (as numbered by the Applicant) of the Remarks, “The only active control element in Coers is sensor 36, positioned at (and only at) the single predetermined higher level 30. When the cold liquid expands due to ambient heat gain and reaches level 30, sensor 36 is cooled, which activates vapor discharge valve 40 to release pressurized vapor. This is the entirety of Coers' control logic: one sensor, at one level, activating one valve. As to the closing of valve 40, Coers states: "Once enough vapor and/or liquid have been released, the temperature will stabilize, and the level of cold liquid will remain at or just below the predetermined higher level. When cold liquid is removed from tank 10 the cold liquid that is in thermal communication with sensor 36 will warm and evaporate and no further signal will be generated to open vent valve 40 or liquid discharge valve 42" (Col. 5, lines 7-14). The valve thus closes when the cold liquid recedes at or just below level 30 - the same and only level 30 at which it opened. There is no defined secondary closing threshold. The valve simply closes when the physical contact between the cold liquid and sensor 36 is broken, which occurs thermally and incidentally at or just below the same level 30. This is a thermostatic hysteresis effect inherent to the mechanical nature of the gas bulb sensor, not a second, independently defined closing setpoint.”
However, this argument is not persuasive as per the Examiner’s BRI of the claims, the crossing of line 30 of Coers is the effective fill level and the secondary threshold is met when the fluid is lowered to at or below the line 30 enough for the sensor 36 to warm up and allow for the valve 40 to close (Coers, Col. 5, lines 8-14, Once enough vapor and/or liquid have been released, the temperature will stabilize, and the level of cold liquid will remain at or just below the predetermined higher level. When cold liquid is removed from tank 10 the cold liquid that is in thermal communication with sensor 36 will warm and evaporate and no further signal will be generated to open vent valve 40 or liquid discharge valve 42). Therefore, the secondary threshold is defined by the fluid being lowered to a point at which the senor is 36 is no longer activated by contact with the cold fluid. Further, claim 1 only limits the secondary threshold to being “different than the initial fill level threshold”. See the rejection of claim 1 above.
Applicant argues on Pg. 21-22 (as numbered by the Applicant) of the Remarks, “The Examiner's argument conflates the initial filling level (level 20, set once by the operator at filling time) with an active control threshold. In Coers, level 20 plays no role whatsoever in the automatic control of valve 40 after filling is complete. The system never closes valve 40 "when level 20 is reached". It closes valve 40 when the cold liquid recedes below level 30 due to the evaporation process. There is only one active control threshold in Coers: level 30. By contrast, claim 1 of the present application expressly requires that the secondary threshold be different from the initial fill level threshold, and that both thresholds are operative in the controller's logic for opening and closing the active venting valve. As described in the specification at paragraph [0033] and [0039], the secondary threshold is an independently defined parameter (e.g., a secondary fill level threshold in the range of approximately 80-85% or a predetermined time period), which is deliberately set below the initial fill level threshold to define a venting cycle that allows the tank to be filled at a higher initial level and to retain more hydrogen over time. This deliberate two-threshold control architecture is entirely absent from Coers.”
However, this argument is not persuasive as claim 1 explicitly says that the secondary threshold is different than the initial fill level threshold. Per the Examiner’s BRI of the claims, the crossing of line 30 of Coers is the effective fill level and the secondary threshold is met when the fluid is lowered to at or below the line 30 enough for the sensor 36 to warm up and allow for the valve 40 to close (Coers, Col. 5, lines 8-14, Once enough vapor and/or liquid have been released, the temperature will stabilize, and the level of cold liquid will remain at or just below the predetermined higher level. When cold liquid is removed from tank 10 the cold liquid that is in thermal communication with sensor 36 will warm and evaporate and no further signal will be generated to open vent valve 40 or liquid discharge valve 42). Further, claim 1 only requires that the active venting valve be opened when the effective fill level exceeds an initial fill level threshold which is explicitly taught by Coers as level 30, which triggers the opening of valve 40, is at a level that exceeds the fill level 20 (Coers, Col. 4, lines 37-47, Vessel 10 is filled with cold liquid, as described above, to the first level 20. After filling, heat gain by the cold liquid causes it to expand to a higher predetermined level 30. Conduit 34 is maintained within the evacuated space 54 to the extent possible to minimize heat leak into vessel 10 and cold liquid drains into conduit 34 as described above. Sensor 36 is cooled by the cold liquid from conduit 34 and an electrical signal or gas pressure activates vapor discharge valve 40 to release pressurized vapor or, when desired, to drain valve 42 to release liquid). Moreover, in response to applicant's argument that the references fail to show certain features of the invention, it is noted that the features upon which applicant relies (i.e., a secondary fill level threshold in the range of approximately 80-85% or a predetermined time period) are not recited in the rejected claim(s). Although the claims are interpreted in light of the specification, limitations from the specification are not read into the claims. See In re Van Geuns, 988 F.2d 1181, 26 USPQ2d 1057 (Fed. Cir. 1993). See the rejection of claim 1 above.
Applicant argues on Pg. 22 (as numbered by the Applicant) of the Remarks, “Finally, the Examiner argues that a person of ordinary skill in the art would have been motivated to reprogram the controller of Westenberger with the teachings of Coers "to provide a greater effective vessel volume available for storage of cold liquid". This motivation is legally insufficient for several reasons: • First, as demonstrated above, Coers does not in fact teach the two-threshold control logic that is the claimed invention. One cannot be motivated to incorporate a teaching that does not exist in the reference.”
However, this argument is not persuasive as per the Examiner’s BRI of the claims, the first level 20 is the initial fill level threshold (Coers, Col. 4, lines 37-47, Vessel 10 is filled with cold liquid, as described above, to the first level 20. After filling, heat gain by the cold liquid causes it to expand to a higher predetermined level 30. Conduit 34 is maintained within the evacuated space 54 to the extent possible to minimize heat leak into vessel 10 and cold liquid drains into conduit 34 as described above. Sensor 36 is cooled by the cold liquid from conduit 34 and an electrical signal or gas pressure activates vapor discharge valve 40 to release pressurized vapor or, when desired, to drain valve 42 to release liquid) and the crossing of line 30 of Coers is the effective fill level and the secondary threshold is met when the fluid is lowered to at or below the line 30 enough for the sensor 36 to warm up and allow for the valve 40 to close (Coers, Col. 5, lines 8-14, Once enough vapor and/or liquid have been released, the temperature will stabilize, and the level of cold liquid will remain at or just below the predetermined higher level. When cold liquid is removed from tank 10 the cold liquid that is in thermal communication with sensor 36 will warm and evaporate and no further signal will be generated to open vent valve 40 or liquid discharge valve 42). Therefore, Coers does in fact teach two thresholds for controlling fill level, the secondary threshold is defined by the fluid being lowered to a point at which the senor is 36 is no longer activated by contact with the cold fluid and the initial fill level threshold is defined by the first level 20. See the rejection of claim 1 above.
Applicant argues on Pg. 22-23 (as numbered by the Applicant) of the Remarks, “Finally, the Examiner argues that a person of ordinary skill in the art would have been motivated to reprogram the controller of Westenberger with the teachings of Coers "to provide a greater effective vessel volume available for storage of cold liquid". This motivation is legally insufficient for several reasons… Second, the physical architectures of Westenberger and Coers are fundamentally incompatible. Coers is a purely passive, thermostatically-controlled mechanical system: a gas bulb sensor at a fixed physical level activates a thermostatic valve through a refrigerant pressure signal. There is no electronic controller, no digital processing, no computed "effective fill level," and no programmable logic. Westenberger, by contrast, features an electronic monitoring system 120 with electrical connections to sensors and valves. Transposing the operating principle of a 1996 thermostat-based LNG storage device into an electronically-controlled liquid hydrogen aircraft fuel tank system is not a matter of "reprogramming a controller" - it requires a fundamental redesign of the sensing and control architecture.”
However, this argument is not persuasive as Coers explicitly discloses the use of electronically measuring the initial fill level and electronic control of the valve 40 (Coers, Alternatively, a differential pressure level switch (not shown) may be used to detect when the liquid level reaches elevation 20 and engage a valve operator to close valve 24; Col. 3-4, Sensor 36 activates a vapor discharge valve 40 to release vapor from vessel 10. Sensor 36 either generates an electrical signal that is transmitted through a wire 41 or passes a gas pressure through a conduit, also represented by number 41. Wire 41 may be part of an electrical circuit that is closed when cold liquid contacts sensor 36 which results in an activating electrical signal being generated to open vapor discharge valve 40). Further, it has been held that broadly providing an automatic or mechanical means to replace a manual activity which accomplished the same result is not sufficient to distinguish over the prior art (MPEP 2144.04, section III). See the rejection of claim 1 above.
Applicant argues on Pg. 22-24 (as numbered by the Applicant) of the Remarks, “Finally, the Examiner argues that a person of ordinary skill in the art would have been motivated to reprogram the controller of Westenberger with the teachings of Coers "to provide a greater effective vessel volume available for storage of cold liquid". This motivation is legally insufficient for several reasons… Third, even accepting for the sake of argument that a skilled artisan would look to Coers for inspiration, the result of the combination would be at best a single-threshold control system in which the venting valve opens and closes at the same level 30 – not the claimed invention with its two distinct, intentionally different thresholds.”
However, this argument is not persuasive as per the Examiner’s BRI of the claims, the first level 20 is the initial fill level threshold (Coers, Col. 4, lines 37-47, Vessel 10 is filled with cold liquid, as described above, to the first level 20. After filling, heat gain by the cold liquid causes it to expand to a higher predetermined level 30. Conduit 34 is maintained within the evacuated space 54 to the extent possible to minimize heat leak into vessel 10 and cold liquid drains into conduit 34 as described above. Sensor 36 is cooled by the cold liquid from conduit 34 and an electrical signal or gas pressure activates vapor discharge valve 40 to release pressurized vapor or, when desired, to drain valve 42 to release liquid) and the crossing of line 30 of Coers is the effective fill level and the secondary threshold is met when the fluid is lowered to at or below the line 30 enough for the sensor 36 to warm up and allow for the valve 40 to close (Coers, Col. 5, lines 8-14, Once enough vapor and/or liquid have been released, the temperature will stabilize, and the level of cold liquid will remain at or just below the predetermined higher level. When cold liquid is removed from tank 10 the cold liquid that is in thermal communication with sensor 36 will warm and evaporate and no further signal will be generated to open vent valve 40 or liquid discharge valve 42). Therefore, Coers does in fact teach two thresholds for controlling fill level, the secondary threshold is defined by the fluid being lowered to a point at which the senor is 36 is no longer activated by contact with the cold fluid and the initial fill level threshold is defined by the first level 20. See the rejection of claim 1 above.
The rejection of independent claim 1 is maintained. The rejections of dependent claims 2-10 are also maintained for at least the reasons described herein.
Conclusion
THIS ACTION IS MADE FINAL. 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.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to DEVON T MOORE whose telephone number is 571-272-6555. The examiner can normally be reached M-F, 7:30-5.
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Frantz Jules can be reached at 571-272-6681. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000.
/DEVON MOORE/Examiner, Art Unit 3763 August 13th, 2026
/FRANTZ F JULES/Supervisory Patent Examiner, Art Unit 3763
Prosecution Insights