Removable Aviation Liquid Gas Storage Device

Abstract

The cryogenic tank system for storing gas on board an aircraft comprises an inner vessel 26 defining a liquefied gas storage chamber 28, an outer casing 27 housing the inner vessel 26, the outer casing 27 being made of a material capable of withstanding temperatures from below -60°C to at least +80°C, and an insulating chamber 29 defined between the inner vessel 26 and the outer casing 27, the helium leak rate being less than 10. -9 The device comprises an insulating chamber 29 evacuated to an airtight state of less than millibar liters per second, two connections supporting the inner container 26 and supported by the outer casing 27, at least one of which is a sliding connection, a removable collector 38 sealingly passing through the outer casing 27 and the inner container 26, and a flexible and insulating neck portion 42 forming a sealed interface between the collector 38 and the outer casing 27 and between the collector 38 and the inner container 26, respectively, the neck portion 42 being formed to surround a part of the collector 38 and passing through the insulating chamber 29 so as to enable the collector 38 to be removed regardless of the pressure in the insulating chamber 29.

Description

Technical Field

[0001] The present invention relates to the field of aviation.

Background Art

[0002] In the aviation industry, initially, high-octane gasoline engines have been used. Since 1945, with the development of jet engines and turbines, kerosene has come to be used. Kerosene has a higher molecular weight, higher energy density, higher efficiency, and lower flammability than gasoline. These fuels are usually stored in tanks located in the wings, the connection between the fuselage and the wings, or the tail fins.

[0003] Due to the trend of reducing carbon dioxide emissions, engines with low fuel consumption have been developed. However, with the development of certain technologies (especially the speed at the blade tip), the effect of reducing carbon dioxide emissions has been decreasing. Such a break from the past is increasingly desired.

[0004] This has led to the development of gas-powered aircraft. Gases with short or no carbon chains produce little or no pollution even when burned with oxygen as needed. On the other hand, H 2 , O 2 , C1, and C2 gases are difficult to store and prone to leakage because the gas molecules are small.

[0005] Such gases are usually stored on the ground in a pressurized case (this type of case is too heavy, too large in volume, and too high in pressure energy to be mounted on an aircraft) or in a cryogenic tank that is welded or adhered. The cryogenic storage of such gases has a limited storage period proportional to the storage amount.

[0006] Furthermore, hydrogen, methane, ethane, ethylene, acetylene, and oxygen stored in a liquid state cannot be used in internal combustion engines, external combustion engines, or fuel cells. For final consumption, they need to be in a gaseous state.

[0007] Therefore, while applying the know-how of aircraft maintenance and avoiding the need for new standardization, there is a need to store the propulsion gas for in-aircraft consumption within the aircraft. In fact, establishing new standardization is a long and time-consuming process, and there is a risk of delaying the market launch of gas-powered aircraft. Since it also takes time and cost to acquire new maintenance know-how, it can lead to a sense of resistance.

Summary of the Invention

[0008] The present invention provides a cryogenic tank device of spherical or elongated shape for storing gas and mounted on an aircraft. The cryogenic tank device of the present invention includes an inner container defining a liquefied gas storage chamber, and an outer casing housing the inner container, the outer casing being composed of a plurality of removable parts enabling access to the inner container and made of a material resistant to temperatures from less than -60°C to at least +80°C, a heat insulation chamber defined between the inner container and the outer casing, the heat insulation chamber being provided with a reduced pressure between the inner container and the outer casing so as to have an airtightness with a helium leak rate of 10 -9 millibar liters / second or less, two connecting parts supporting the inner container and supported by the outer casing, at least one of which is a sliding type connecting part, a removable collector penetrating the outer casing and the inner container in a sealed state, and a neck part forming a sealed interface between the collector and the outer casing and between the collector and the inner container, the neck part having flexibility and heat insulation properties. The neck part is formed so as to surround a part of the collector. The neck part is provided through the heat insulation chamber so as to enable removal of the collector regardless of the pressure in the heat insulation chamber. According to the present invention, the cryogenic tank can meet the requirements of aviation practice (particularly thermal requirements), especially with regard to suppression of mechanical deformation and compactification of ducts.

[0009] In one embodiment, the cryogenic tank device includes a heat-insulating stopper assembly that is removably attached to the collector and is accessible from the outside. Thereby, the heat insulation property is improved.

[0010] In one embodiment, one of the connection portions includes an axial recess (a portion recessed in the axial direction) provided in the outer casing, and the axial recess is configured to receive and support an axial protrusion (a portion protruding in the axial direction) of the inner container. Such a connection is adapted to the expansion that may occur.

[0011] In one embodiment, the outer casing includes a frame, a plurality of sealed panels, and a pressure-resistant seal provided between the frame and the panels and / or between the plurality of panels. Thereby, maintenance becomes easier.

[0012] In one embodiment, the frame includes a plurality of rib portions and a plurality of spar portions (beam portions). Thereby, the structure is strengthened.

[0013] In one embodiment, the seal is housed in a groove and, in a free state, protrudes from the groove by a height of less than 10% of the height of the seal. Thereby, a high level of leak prevention is obtained.

[0014] In one embodiment, the cryogenic tank device includes an anti-vibration member provided in the inner container. Thereby, the mechanical operation (particularly, stability) of the cryogenic tank device is improved.

[0015] In one embodiment, the cryogenic tank device includes a reinforcing member (preferably, a brace or a tie rod) provided in the inner container. Thereby, the cryogenic tank device (particularly, the inner container) can be lightened.

[0016] In one embodiment, the cryogenic tank device includes at least one support ring attached between the inner container and the outer casing at a position spaced apart from the connection portion in the heat insulation chamber. Thereby, the rigidity is enhanced.

[0017] In one embodiment, a hydrogen absorption material is disposed in the heat insulation chamber. Thereby, the heat insulation chamber is maintained at a low pressure.

[0018] In one embodiment, a hydrogen presence detector is provided in the heat insulation chamber. Thereby, it becomes possible to sound an alarm when the limit value is exceeded.

[0019] In one embodiment, the assembly of the present invention includes a cryogenic tank device as described above, a temporary storage tank that constitutes gasification means for pressurizing the gas supplied by the cryogenic tank device, an upstream valve that is opened with respect to the flow of liquid during the filling stage into the temporary storage tank and is closed outside the filling stage, a downstream valve that is opened with respect to the flow of gas during the discharge stage from the temporary storage tank and is closed outside the discharge stage, a compressor disposed downstream of the downstream valve, and a pressure reducer disposed downstream of the downstream valve. The upstream valve and the downstream valve are closed during the gasification stage, and the upstream valve and the downstream valve are configured to be on-off (all-or-nothing) controlled. The compressor is operated so that at the end of the discharge stage, the pressure in the temporary storage tank becomes a value lower than the value of the pressure in the cryogenic tank device. The pressure reducer is operated so that at the start of the discharge stage, the pressure of the gas at the outlet becomes a value lower than the pressure in the temporary storage tank. This device guarantees, regardless of the state of the device, the required autonomy for the aircraft depending on the volume in the temporary storage tank. The temporary storage tank is provided with a gas pressure of several hundred bar, and the selected gas pressure is supplied to the gas consumption section. The above valves are reliable. The discharge from the temporary storage tank can be made sufficient to increase the amount of gas available at the gas consumption section and to make the pressure in the temporary storage tank at the end of the discharge lower than the current pressure in the device. The filling of the temporary storage tank is performed by operating the cryogenic valve under the influence of the pressure difference. By not using a cryogenic pump, the weight is reduced and the risk of accidents is reduced.

[0020] In one embodiment, the temporary storage tank is provided for use pressures exceeding 500 bar.

[0021] In one embodiment, the cryogenic tank device is provided for use pressures less than 8 bar.

[0022] Other features and advantages of the present invention can become apparent from the following detailed description and the following attached drawings.

Brief Description of the Drawings

[0023]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

[0024] The accompanying drawings not only supplement the present invention but may also serve to contribute to the definition of the present invention as needed.

Modes for Carrying Out the Invention

[0025] An aircraft gas storage device is configured to be mountable on an aircraft (e.g., an airplane, a drone, a helicopter, etc.). The aircraft gas storage device stores a liquid and supplies a gas. In other words, the gas is stored in a cryogenic tank in a liquid state at a very low temperature. The cryogenic tank cannot withstand a high pressure exceeding particularly 10 bar.

[0026] The gas to be stored is selected from hydrogen, methane, ethane, ethylene, acetylene, and oxygen.

[0027] The applicant of the present application also takes into account the phenomenon that gasification occurs rapidly even in the ambient atmosphere of -55°C at high altitudes. For example, gaseous hydrogen at 0°C and 1 atmosphere has a density about 800 times lower, that is, a volume about 800 times larger, compared to liquid hydrogen at -253°C.

[0028] Furthermore, in the aircraft maintenance regulations, it is required that most parts of the aircraft can be removed for repair or replacement. As a result, even without maintenance equipment specific to the aircraft model, the aircraft can land anywhere as long as it is a location that conforms to the weight of the aircraft and the landing requirements (airport in the case of an airplane, takeoff and landing site in the case of a helicopter). When damage is detected, the aircraft is configured to be repaired permanently or temporarily in accordance with the manufacturer's manual and documents approved by the aviation safety authority, or to be disassembled to replace or repair faulty parts. It is desirable that the parts of the aircraft can be easily accessed by maintenance personnel. The parts to be replaced are preferably configured to be as small as possible to facilitate handling and transportation. The parts to be repaired are preferably repairable by proven tools and methods commonly used in the aviation industry.

[0029] Since the aircraft is inspected, for example, daily or weekly, the aircraft will stay on the ground for a period inversely proportional to that frequency.

[0030] However, gas tanks in the ground industrial and space fields are not subject to such requirements and are not designed with such repairability in mind.

[0031] The applicant of the present application has confirmed the need for storage using an aircraft cryogenic tank mounted on an aircraft, particularly for the storage of hydrogen, methane, ethane, ethylene, acetylene, or oxygen.

[0032] The applicant of the present application has confirmed the need for a removable aircraft cryogenic tank that can be inspected and repaired according to the aircraft inspection mode. Furthermore, there is a need for a tank with a high ratio of effective volume to outer volume, a high ratio of contained gas mass to total mass, high reliability, and high safety.

[0033] As shown in the figure, the aircraft gas storage device (aircraft cryogenic tank) has an overall elongated shape and has rounded (curved) both ends. The aircraft gas storage device may have an annular shape with an axis along the longitudinal direction. The aircraft gas storage device includes an outer casing and an inner container. The inner container forms a liquefied gas storage chamber. The inner container is housed within the outer casing. Generally, the inner container and the outer casing are arranged at a distance from each other.

[0034] In the illustrated embodiment, the aircraft gas storage device has a cylindrical central portion and hemispherical both ends. However, shapes other than cylindrical, annular, and hemispherical may be manufactured.

[0035] Each cryogenic tank is insulated so as to be able to contain a liquid fuel or oxidizer at -253°C. Each cryogenic tank can withstand a maximum operating pressure of about 6 to 10 bar.

[0036] In the embodiments shown in FIGS. 1 to 3, the cryogenic tank 2 has an elongated shape, particularly arranged along a predetermined axis (around a predetermined axis). The cryogenic tank 2 includes domed (hemispherical) both ends and a substantially cylindrical central portion. As an alternative, the cryogenic tank 2 may have a spherical shape.

[0037] The cryogenic tank 2 includes an inner container 26 and an outer casing 27. The inner container 26 defines a liquefied gas storage chamber 28 for accommodating the loaded gas at liquefaction temperature and the space of the evaporated gas. The inner container 26 is sealed. The inner container 26 can withstand the liquefaction temperature (for example, -253°C in the case of hydrogen). The outer casing 27 houses the inner container 26. The outer casing 27 consists of a plurality of removable parts so as to be accessible to the inner container 26. The outer casing 27 protects the inner container 26 from impacts. The outer casing 27 guarantees the structural strength of the aviation gas storage device. The outer casing 27 is made of a material that can withstand temperatures from less than -60°C to at least +80°C.

[0038] An insulation chamber 29 is defined (formed) between the inner container 26 and the outer casing 27. The insulation in the insulation chamber 29 is ensured by reducing the pressure compared to the atmospheric pressure. Further, a solid insulation material may be disposed in the insulation chamber 29. Between the inner container 26 and the outer casing 27, a vacuum insulation chamber 29 having an airtightness with a helium leak rate (measured value by a helium leak test) of 10 -9 millibar liters / second or less is defined (formed). The airtightness of the insulation chamber 29 referred to here includes the airtightness with respect to the inside of the inner container 26 and the airtightness with respect to the external atmosphere.

[0039] The inner container 26 may be made of a welded metal alloy. Examples of the metal alloy include Al-Cu-Li alloys (especially 2050 alloy or 2099 alloy), Al-Cu alloys (especially 2219 alloy), and stainless steels (especially SUS304, SUS304L, SUS316, SUS316L). The inner container 26 has an elongated shape with two dome-shaped (hemispherical) both ends surrounding (clamping) the body. The body of the inner container 26 may be cylindrical. The body of the inner container 26 may be a rotating body.

[0040] The outer casing 27 includes a frame 30, a plurality of sealing (airtight) panels 31, and a plurality of pressure-resistant seals (pressure-resistant seals) between the frame 30 and the panels 31 and / or between the plurality of panels 31. The panel 31 may be assembled to the frame 30 by screwing.

[0041] The frame 30 includes a plurality of rib portions 32 and a plurality of spar portions (web portions) 33. The rib portions 32 may have, for example, an annular, closed contour. The spar portions 33 extend in the longitudinal direction. The plurality of spar portions 33 are connected to each other at both ends of the outer casing 27.

[0042] The panel 31 is made of a welded metal alloy or a composite material. Examples of the composite material include an epoxy resin containing carbon fiber, Kevlar fiber, and / or glass fiber. Examples of the metal alloy include Al-Mg alloy (especially 5086 alloy), Al-Mg-Si alloy (especially 6061 alloy), and Al-Cu-Li alloy (especially 2195 alloy).

[0043] A seal is provided between the panel 31 and the frame 30. The seal may be a metal seal or may be made of a synthetic material (e.g., elastomer). In the case of a seal made of a synthetic material, a groove is formed in the panel 31 or the frame 30 to accommodate the seal. In the free state, the seal protrudes from the groove by a height of less than 10% of the height of the seal. Note that the height of the seal means the diameter of the O-ring.

[0044] The cryogenic tank 2 includes two connection portions between the outer casing 27 and the inner container 26 to support the inner container 26. The connection portions are configured such that the heat conduction is extremely low.

[0045] At least one of the connection parts is a sliding connection part for enabling the difference in expansion between the outer casing 27 and the inner container 26 to be accommodated. The two connection parts are supported by the outer casing 27. The first connection part is located at the outermost tip. The outermost tip connection part (the first connection part) 34 is provided with a central protruding part (axial protruding part) at one end of the inner container 26. The central protruding part of the inner container 26 cooperates with an axial recess (a recess recessed axially) provided in the outer casing 27 so as to form a housing for the central protruding part, and is slidable axially over a stroke of several millimeters. Thereby, the contraction of the inner container 26 when filling with liquefied gas and the expansion of the inner container 26 after discharging the liquefied gas can be freely achieved. The outermost tip connection part (the first connection part) 34 is configured to have a long heat conduction path.

[0046] The second connection part is disposed at a position spaced a predetermined distance from the end on the opposite side of the first connection part. The second connection part is provided so as to surround the inner container 26. The second connection part is mounted in the heat insulation chamber 29. The second connection part includes a support ring 35. The support ring 35 is mounted between the inner container 26 and the outer casing 27. The support ring 35 is mounted at a position spaced from the connection part(s) in the heat insulation chamber 29.

[0047] The support ring 35 includes a plurality of outer sectors 36 protruding radially outward. The number of the outer sectors 36 is three in this embodiment. The outer sectors 36 have an outer peripheral surface that contacts the inner peripheral surface of the outer casing 27. The outer sectors 36 occupy an angular range of about 15° to 40°.

[0048] The support ring 35 includes a plurality of inner sectors 37 that project radially inward. The number of inner sectors 37 is three in this embodiment. The inner sectors 37 have concave surfaces that contact the outer peripheral surface of the inner container 26. The inner sectors 37 occupy an angular range of about 15° to 40°. The outer sectors 36 and the inner sectors 37 are alternately arranged. The outer sectors 36 and the inner sectors 37 are angularly spaced from each other. Preferably, three inner sectors 37 and three outer sectors 36 each spanning an angular range of about 20° to 30° are alternately arranged, sandwiching a region without a protrusion that occupies an angular range of about 40° to 30°. The support ring 35 is held by sufficient friction with the inner container 26 or by permanent fixation.

[0049] The support ring 35 is made of a composite material with low thermal conductivity and high mechanical strength.

[0050] The cryogenic tank 2 is provided with a removable collector 38 that penetrates through the outer casing 27 and the inner container 26 in a sealed state. The collector 38 is provided with a linear rod 39 for extracting the liquefied gas inside the inner container 26. The rod 39 is made of a heat-insulating material. The collector 38 has a first open end inside the inner container 26. The collector 38 has a second open end outside the outer casing 27. The second open end is provided so as to be connectable to a duct (for example, an outlet duct 4 as shown in FIG. 6). The first open end and the second open end are connected by a port. The first open end is disposed near the bottom of the inner container 26 in the attached state. The first open end is a free end. Thereby, the collector 38 discharges the liquefied gas. When the liquid level becomes low, the discharge of the liquefied gas is stopped. In other words, during operation, the inside of the inner container 26 contains a gas phase and a liquid phase. At the end of filling, the liquid phase is maximized and the gas phase is minimized. At the end of discharge, the liquid phase is minimized or the liquid phase disappears and the gas phase is maximized. The liquid phase is discharged. By discharging the liquid phase, the diameter of the duct can be significantly reduced compared to the discharge of the gas phase. Also, the compactness of the members on the downstream side of the cryogenic tank 2 is improved. The rod 39 is also used for filling the liquefied gas.

[0051] The collector 38 includes a plug 41 that surrounds the rod 39 on the second open end side. The plug 41 is made of a heat-insulating material. The plug 41 protrudes outward from the outer casing 27. The plug 41 may be provided with a gripping area for removal, for example, for maintenance purposes. The outer diameter of the plug 41 is larger than the diameter of the rod 39. The plug 41 forms a sealed head portion (seal head portion) that can be removed from the cryogenic tank 2.

[0052] The stopper assembly includes a stopper plug 41 and a stopper cap 45. In the case of an aircraft of the airplane type or drone type, the cryogenic tank 2 may be attached in a state where the stopper assembly is directed forward of the aircraft and the free end of the rod 39 is directed rearward of the aircraft. Thereby, by utilizing the general several degrees of inclination of the aircraft, more complete filling of the liquefied gas and more complete discharge of the liquefied gas become possible. The cryogenic tank 2 may be attached in an inclined state, particularly by support members having different heights before and after the cryogenic tank 2.

[0053] Furthermore, the collector 38 includes a liquid level gauge 40. The liquid level gauge 40 extends along the rod 39. The liquid level gauge 40 is connected to the outside of the tank by wired communication through the plug 41. The liquid level gauge 40 supplies a signal representing the liquid level height as an output. The liquid level gauge 40 may be capacitive. When the collector 38 has a small angle (inclination) with respect to the horizontal, the accuracy of the liquid level gauge becomes even higher. In fact, if the resolution of the liquid level gauge and the height of the inner container 26 are constant, the longer the length of the inner container 26, the longer the length of the liquid level gauge, and thereby the accuracy is improved. For example, a liquid level gauge at 30° with respect to the horizontal has twice the accuracy compared to a vertical liquid level gauge.

[0054] The collector 38 includes a gas vent (vent hole) 53 for rapid discharge in case of overpressure. The vent 53 also has a function of discharging gas to avoid overpressure during filling. The vent 53 also has a function of repressurizing by introducing gas as needed during discharge. The vent 53 is disposed within the plug 41 and is exposed within the inner container 26 in the vicinity of the plug 41. A liquid check valve is provided in the vent 53.

[0055] The vent 53 is disposed within the plug 41 and opens into the inner container 26 in the vicinity of the plug 41. Thereby, the vent 53 is connected to the gaseous space (gas space) of the inner container 26. The vent 53 is connected to a duct passing through the plug 41. A bypass valve having an opening pressure lower than the allowable pressure within the cryogenic tank 2 may be connected to the duct. A rupture disk having a rupture pressure lower than the allowable pressure within the cryogenic tank 2 may be connected to the duct. The bypass valve and the rupture disk are attached in parallel.

[0056] The collector 38 includes a temperature sensor disposed at the lower part inside the plug 41. The temperature sensor provides information on the temperature measured within the inner container 26.

[0057] The cryogenic tank 2 includes a heat-insulating neck portion 42 (thermal insulation neck). The neck portion 42 has a hole. The neck portion 42 is made of, for example, metal. As the metal, one having low thermal conductivity, mechanical resistance, flexibility, and not allowing hydrogen to pass through is selected. The neck portion 42 is welded or screwed to the inner container 26 in a sealed state. The neck portion 42 is welded or screwed to the outer casing 27 in a sealed state. The neck portion 42 has sufficient flexibility to accommodate the difference in expansion between the inner container 26 and the outer casing 27. The neck portion 42 includes an outer wall portion fixed to the inner container 26 and the outer casing 27. The neck portion 42 includes an inner wall portion spaced apart from the inner container 26 and the outer casing 27. The inner wall portion may be fixed to the outer wall portion at both ends of the neck portion 42.

[0058] The outer wall portion of the neck portion 42 is cylindrical. The inner wall portion of the neck portion 42 is a bellows-shaped tube. The inner wall portion of the neck portion 42 may be made of a metal plate having a thickness thinner than that of the metal plate of the outer wall portion of the neck portion 42 in order to enhance elastic deformability. The inner wall portion of the neck portion 42 may have a bellows shape capable of enhancing elastic deformability. Since the inner wall portion of the neck portion 42 has a bellows shape (for example, a corrugated shape), the contact surface between the inner wall portion of the neck portion 42 and the plug 41 is reduced, thereby reducing the thermal conductivity.

[0059] The bellows-shaped inner wall portion of the neck portion 42 is preferably composed of two concentric sheets. The two sheets are fitted to each other and connected to each other at both ends. Thereby, a double wall is formed, and the risk of leakage can be reduced. When a hole is opened in one of the two sheets, a gas pressure higher than the pressure in the heat insulation chamber and lower than the atmospheric pressure is applied between the two sheets, and detection can be performed by monitoring the change in the applied pressure. When the applied pressure decreases, it indicates leakage from the larger-diameter sheet of the two sheets into the heat insulation chamber. When the applied pressure increases, it indicates leakage from the smaller-diameter sheet of the two sheets into the hole of the neck portion 42. Thereafter, the neck portion 42 can be replaced. Further, when leakage occurs only in one of the two sheets, the heat insulation chamber maintains a low pressure and ensures low heat conduction, so the cryogenic tank 2 can operate until the next maintenance work. If one sheet loses its sealing property, the low heat conduction characteristics of the heat insulation chamber are impaired, so the cryogenic tank 2 is urgently discharged so that the contents are lost.

[0060] The neck portion 42 forms sealed boundary surfaces between the collector 38 and the outer casing 27, and between the collector 38 and the inner container 26, respectively. The neck portion 42 maintains the airtightness between the outer casing 27 and the inner container 26 regardless of the position of the collector 38 or even if the collector 38 does not exist. The neck portion 42 is fixedly sealed in a hole opened in the outer casing 27. The neck portion 42 is fixedly sealed in a hole opened in the inner container 26. The hole in the outer casing 27 and the hole in the inner container 26 are provided at a rounded (hemispherical) one end of the cryogenic tank 2 near the outer peripheral surface at the upper part of the cryogenic tank 2. The collector 38 extends outward beyond the neck portion 42 at its outer end. The collector 38 extends downward toward the inside of the cryogenic tank 2 and beyond the neck portion 42 toward the other rounded (hemispherical) end of the cryogenic tank 2.

[0061] The neck portion 42 is formed so as to surround a part of the collector 38. The neck portion 42 penetrates through the heat insulation chamber 29 so that the collector 38 can be removed regardless of the pressure in the heat insulation chamber 29. A through hole 43 is provided in the neck portion 42. A plug 41 of the collector 38 is detachably attached to the through hole 43. A female annular tooth 44 may be provided on the contact surface between the neck portion 42 and the plug 41, whereby the length of the leakage path is increased and it becomes easier to mechanically hold the collector 38 in the neck portion 42. Here, the annular tooth 44 is V-shaped (chevron). The plug 41 has a smooth rotating outer surface in a free state. The plug 41 is fitted into the neck portion 42. There may be some play between the bellows-shaped inner wall portion of the neck portion 42 and the plug 41. A liquid deflector is provided inside the neck portion 42 in the vicinity of the liquefied gas storage chamber 28. The plug 41 is made of a heat insulating material. The plug 41 may include a durable shell (outer shell portion) and a synthetic resin foam having heat insulating properties inside the shell.

[0062] In the embodiments of FIGS. 6 and 7, the neck portion 42 is welded to the inner container 26 around its outer wall portion. The neck portion 42 has a flange that is overlapped with the flange of the inner container 26. The above welding can be performed by an electron beam directed at the flange. The neck portion 42 is welded to the outer casing 27 at a position spaced apart from the welded portion to the inner container 26 around its outer wall portion. The outer wall portion of the neck portion 42 comprises two separate parts that are separated from each other. One of these parts is connected to the inner container 26, and the other part is connected to the outer casing 27.

[0063] The inner wall portion of the neck portion 42 connects the two parts of the outer wall portion. The inner wall portion of the neck portion 42 comprises two concentric sheets having a thickness of 0.1 mm to 0.2 mm. On the outside, the neck portion 42 comprises a collar 54 directed towards the inner wall portion. The collar 54 connects the inner wall portion and the outer wall portion of the neck portion 42 in a sealed state. A seal 55 is fixed to the collar 54, in particular by screwing. The seal 55 contacts the plug 41 of the collector 38. Here, there is no liquid level gauge.

[0064] The cryogenic tank 2 comprises a cap 45 permanently attached to the collector 38. The cap 45 is accessible from the outside. The cap 45 is fixed to the rod 39 by screws or bolts. The cap 45 is arranged outside the outer casing 27. The cap 45 is arranged at the outer end of the collector 38. The cap 45 is sealed.

[0065] The cryogenic tank 2 is provided for a service pressure of less than 8 bar (in particular, 6 bar).

[0066] Advantageously, the cryogenic tank 2 includes an anti-vibration member provided inside the inner container 26. The anti-vibration member includes one or more perforated panels that divide the internal volume of the inner container 26 into a plurality of regions. The openings of the perforated panels may have a surface area of about 1% to 5% of the surface area of the perforated panels. The perforated panels may be provided along the longitudinal direction or along the transverse direction. The perforated panels can reduce the moving speed of the liquefied gas inside the inner container 26 during acceleration (for example, during takeoff, landing, or atmospheric turbulence).

[0067] Advantageously, the cryogenic tank 2 includes a reinforcing member inside the inner container 26. The reinforcing member may include at least one brace (cross member) or tie rod (connecting rod) that connects regions on opposite sides of the inner container 26. The reinforcing member makes it possible to reduce the weight of the remaining part of the structure of the inner container 26.

[0068] A hydrogen absorbent 46 (for example, a nanoporous material) is provided in the heat insulation chamber 29. When some leakage occurs, the loss of heat insulation due to the pressure increase in the heat insulation chamber 29 is reduced. After such leakage occurs, the outer casing 27 is removed to open the heat insulation chamber 29, and the hydrogen absorbent 46 is removed, so that hydrogen is desorbed, for example, by heating.

[0069] A hydrogen presence detector 47 is provided in the heat insulation chamber 29. Thereby, the presence of hydrogen is monitored. If the leakage is severe, a command to urgently empty the inner container 26 may be issued. If the leakage is minor, maintenance work may be expected. The maintenance work may include repair of the inner container 26 to repair the leakage, replacement or desorption of the hydrogen absorbent 46 if appropriate, and evacuation of the heat insulation chamber 29.

[0070] In the embodiments shown in FIGS. 1 to 3, the outer casing 27 comprises two separable parts 48, 49. The first part 48 constitutes one end and the body. The second part 49 constitutes the other end (opposite to the first part 48). The first part 48 and the second part 49 are connected to each other in a sealed and separable state via two sealing rings 50, 51 that provide a sealing surface for metals (between metals) by engagement. The above-mentioned engagement may be an engagement between a conical surface and a conical surface, an engagement between a conical surface and an annular surface, or an engagement between a flat surface and a flat surface. For such engagement, for example, an O-ring made of shrink-fitted metal (especially a copper alloy) or an elastomer is used. The above-mentioned engagement is ensured particularly by axial tightening with bolts. The sealing rings 50, 51 are annular.

[0071] In the embodiment shown in FIG. 4, the outer casing 27 is composed of a plurality of sections. The two sections are connected in a sealed state by the sealing rings 50, 51 as described above. The plurality of sections may be standardized to accommodate various capacities of the inner container 26 by using one end section, one or more central sections, and one end section perforated for the neck portion 42. A plurality of support rings 35 may be provided.

[0072] In the embodiment shown in FIG. 5, the frame 30 of the outer casing 27 comprises a plurality of annular rib portions 32, a plurality of spar portions (girder portions) 33 parallel to the longitudinal axis, and a plurality of brace portions (diagonal bracing portions) extending obliquely. The outer casing 27 comprises a plurality of substantially triangular panels 31 respectively attached between one rib portion 32, one spar portion 33, and one brace portion, and dome-shaped (hemispherical) panels at both ends. The triangular panels 31 are provided so that the frame 30 is visible (exposed). The dome-shaped (hemispherical) panels cover the frame 30 beyond the rib portions 32.

[0073] In the embodiment shown in FIG. 6, the distribution circuit 1 includes a first valve 11 for each cryogenic tank 2. The first valve 11 is attached to the outlet duct 4. The first valve 11 is controllably switched between an open position and a closed position. The intermediate position of the first valve 11 is dynamic in the sense that the first valve 11 passes through the intermediate position during movement. In other words, the first valve 11 is an on-off valve. The first valve 11 may be disposed immediately downstream of the flow meter 22.

[0074] The first valve 11 can communicate with the cryogenic distributor 5. The cryogenic distributor 5 may include a common pipe 6 connecting the outlets of the plurality of first valves 11. The cryogenic distributor 5 is cryogenic in the sense that liquid fuel and / or oxidant passes through it.

[0075] The cryogenic distributor 5 has a plurality of outlets, specifically, for example, three outlets. A second valve 12 is attached to each outlet of the cryogenic distributor 5. The second valve 12 is controllably switched between an open position and a closed position. The intermediate position of the second valve 12 is dynamic in the sense that the second valve 12 passes through the intermediate position during movement. In other words, the second valve 12 is an on-off valve. In the illustrated example, three second valves 12 are provided.

[0076] The central tank (temporary storage tank) 7 is attached downstream of each second valve 12. In this embodiment, three central tanks 7 are provided. Each central tank 7 also functions as a gasifier (gasification means). Insulation is not required. Each central tank 7 receives liquid and supplies gas downstream. Inside each central tank 7, a pressure increase stage, i.e., a gasification stage, occurs between filling and discharging. Each central tank 7 can withstand a maximum operating pressure of about 300 to 1000 bar. Each central tank 7 is configured to operate in a temperature range of -253°C to +60°C. Inside the central tank 7, it is in a gas-liquid two-phase state in some operating stages and in a gas single-phase state in other operating stages. A heating member (heater) 8 may be attached to each central tank 7.

[0077] Downstream of each central tank 7, a third valve 13 for supplying gas is provided, and a pressure reducing valve (pressure reducer) 9 is provided downstream of the third valve 13. The pressure reducing valve 9 restricts the pressure for supplying gas to the consumption pressure set by the manufacturer of the gas consumption unit 3. The pressure reducing valve 9 operates when the pressure in the central tank 7 is higher than the consumption pressure, and does not operate otherwise. The consumption pressure is lower than the maximum pressure of the central tank 7. The consumption pressure is independent of the maximum pressure of the cryogenic tank. The third valve 13 is an on-off valve.

[0078] A controllable fourth valve 14 may be provided downstream of each pressure reducing valve 9. The fourth valve 14 is an on-off valve.

[0079] The fourth valve 14 (i.e., the pressure reducing valve 9) can communicate with the manifold 10 according to the selected option. The manifold 10 may be composed of a single conduit connecting the outlets of a plurality of fourth valves 14 (i.e., pressure reducing valves 9). The gas flows through the manifold 10. The manifold 10 is connected downstream to a supply line (supply pipe) 23 to the gas consumption unit 3. Generally, one supply line 23 is provided for each gas consumption unit 3. A controllable supply valve 24 may be provided in each supply line 23. The supply valve 24 is a variable flow rate valve.

[0080] The distribution circuit 1 includes at least one compressor 20 connected to the manifold 10. Usually, two compressors 20 are provided in parallel for redundancy. The compressor 20 is electric. A controllable upstream valve may be provided for the compressor 20. The compressor 20 sends gas into the manifold 10. In particular, when there is one gas consumption unit 3, the manifold 10 is composed of a single pipe (conduit).

[0081] Downstream of each central tank 7, a fifth valve 15 for supplying gas is provided. Downstream of the fifth valve 15, a second manifold is provided. The second manifold is connected to the compressor 20. The fifth valve 15 can separate the central tank 7 from the compressor 20. The fifth valve 15 is controllable. The fifth valve 15 is an on-off valve.

[0082] The compressor 20 raises the pressure so as to supply gas at a pressure equal to the consumption pressure set by the manufacturer of the gas consumption unit 3. The consumption pressure is lower than the maximum pressure of the central tank 7. The compressor 20 takes out gas at a pressure lower than the consumption pressure from the central tank 7 so as to supply it to the manifold 10 and the gas consumption unit 3. As the central tank 7 becomes more completely empty, an increase in the autonomy (supply range) brought about by the gas contained in the central tank 7, or a decrease in the volume of the central tank 7, is brought about.

[0083] When the central tank 7 becomes sufficiently empty and the internal pressure of the central tank 7 becomes lower than the pressure in one of the plurality of cryogenic tanks, during subsequent filling of the empty tank, due to the pressure difference, liquid can be transferred from the cryogenic tank to the central tank 7. As a result, the liquid in the cryogenic tank is drawn into the central tank 7 until pressure equilibrium is reached. Omission of the cryogenic pump becomes possible, thus reducing weight and energy consumption.

[0084] The distribution circuit 1 provides a combination of individual states for each cryogenic tank, each central tank 7, and each gas consumption unit 3. A plurality of gas consumption units 3 can operate simultaneously. In the normal mode, discharge from one cryogenic tank is performed, and the other tanks are closed without operating. However, in a specific situation, for example, to lower the pressure of a plurality of cryogenic tanks, a specific mode in which discharge is performed from a plurality of cryogenic tanks can be provided. The central tank 7 has a filling mode, a gasification mode, a gas storage mode, and a discharge mode.

[0085] When the discharge from one cryogenic tank is in progress, the corresponding first valve 11 is open and the other first valves 11 are closed. When gas is being supplied to one gas consumption unit 3, the corresponding supply valve 24 is open.

[0086] When one central tank 7 is in the filling mode, the second valve 12 connected to the central tank 7 is open and at least one first valve 11 is open. The other second valves 12 are closed except when two central tanks 7 are filled simultaneously. The third valve 13 connected to the central tank 7 is closed. The fifth valve connected to the central tank 7 is closed.

[0087] When one central tank 7 is in the gasification mode, the second valve 12 connected to the central tank 7, the third valve 13 connected to the central tank 7, and the fifth valve 15 connected to the central tank 7 are closed. The gasification mode ends in a short time, particularly when the ambient atmosphere is warm and / or when the central tank 7 is heated.

[0088] When one central tank 7 is in the discharge mode, the second valve 12 connected to the central tank 7 is closed. At the initial stage of the discharge mode, the pressure in the central tank 7 is higher than the consumption pressure. The third valve 13 connected to the central tank 7 is open, the corresponding fourth valve 14 is open, and the fifth valve connected to the central tank 7 is closed. The gas is depressurized at the pressure reducing valve 9 and supplied to the manifold 10 at the consumption pressure. Then, the gas is consumed by the gas consumption unit 3.

[0089] At any given time, out of the three central tanks 7, one central tank 7 is in the filling mode, another central tank 7 is in the gasification mode and subsequent storage mode, and the remaining central tank 7 is in the discharge mode. Due to the different durations of the modes, there may be a situation where two central tanks 7 are in the filling mode and the remaining central tank 7 is in the discharge mode, and a situation where two central tanks 7 are in the discharge mode and the remaining central tank 7 is in the filling mode. Also, there may be a situation where two central tanks 7 are in the storage mode and the remaining central tank 7 is in the discharge mode, and a situation where two central tanks 7 are in the discharge mode and the remaining central tank 7 is in the storage mode.

[0090] In this embodiment, a flow meter 22 is arranged at the outlet of each liquid fuel source (oxidant source). The flow meter 22 provides sufficiently accurate information regarding the amount of liquid supplied to the central tank 7 as described above.

[0091] In this embodiment, the distribution circuit 1 includes a control unit 25 that receives, for example, an external command from the gas consumption unit 3 outside the aircraft tank device or the central control unit of the aircraft and liquid flow rate data from the flow meter 22. The control unit 25 generates and transmits commands to the above-described controllable valves (the first, second, third, fourth, and fifth valves, and the supply valve 24). The command may be a command to "open" or a command to "close". The control unit 25 manages combinations of individual states.

[0092] Alternatively, the first valve 11 may be replaced with at least one multi-way valve having a plurality of inlets and one outlet. In this case, it is advantageous to provide a multi-way valve having a mixing position (in particular, at least one position for simultaneously discharging from two or more cryogenic tanks so as to reduce pressure while preventing loss to the atmosphere).

[0093] Alternatively, the second valve 12 may be replaced with at least one multi-way valve having one inlet and a plurality of outlets, one for each central tank 7. The multi-way valve forms a dispenser.

[0094] Alternatively, the plurality of pressure reducing valves 9 may be replaced by a single pressure reducing valve 9 with which the third valve 13 can communicate. In this case, the third valve 13 may be replaced by at least one multi-way valve having a plurality of inlets and one outlet to the pressure reducing valve 9. Accordingly, the plurality of fourth valves 14 are replaced by a single fourth valve 14 that is not controlled when appropriate.

[0095] Alternatively, the fifth valve 15 may be replaced by at least one multi-way valve having a plurality of inlets (one inlet for each central tank 7) and one outlet to one or more compressors 20. The multi-way valve forms the manifold 10.

[0096] Since the cryogenic tank is exposed to the evaporation of the liquid, a gas collection circuit may be provided at the upper part of the cryogenic tank. The gas collection circuit may be operated when the threshold pressure is exceeded via a calibration pressure valve. The gas collection circuit includes a compressor for reinjecting the gas downstream (for example, between the fifth valve 15 and the compressor 20).

[0097] Optionally, additional flow meters may be arranged at the inlets of the respective temporary storage tanks (buffer tanks). Thereby, the redundancy of the liquid flow measurement is ensured.

[0098] The capacity of the cryogenic tank device is 10 kg to 10,000 kg in terms of gas weight, preferably 100 kg to 10,000 kg in terms of gas weight.

[0099] The temporary storage tank (temporary storage gasification tank, central tank) 7 is provided to pressurize the gas supplied by the cryogenic tank device. The upstream valve 12 (second valve 12) is provided to open with respect to the liquid flow during the filling stage of the temporary storage tank 7 and to close during the discharge stage. At least one downstream valve 13, 15 (third valve 13, fifth valve 15) is provided to open with respect to the gas flow during the discharge stage of the temporary storage tank 7 and to close other than during the discharge stage. The upstream valve 12 and the downstream valves 13, 15 are closed during the gasification stage. The upstream valve 12 and the downstream valves 13, 15 are under on-off control. Downstream of the downstream valve 15, at least one compressor 20 is arranged. The compressor 20 operates at the end of the discharge stage to make the pressure in the temporary storage tank 7 lower than the value of the pressure in the cryogenic tank device. Downstream of the downstream valves 13, 15, a pressure reducing valve 9 is arranged. The pressure reducing valve 9 operates at the start of the discharge stage to make the pressure of the gas at the outlet lower than the pressure in the temporary storage tank 7.

[0100] A cryogenic tank device for storing gas on a railway, road, or sea has a spherical or (particularly, along the longitudinal axis) elongated shape, an inner container 26 defining a liquefied gas storage chamber, and an outer casing 27 housing the inner container 26, the outer casing 27 being composed of a plurality of removable parts to enable access to the inner container 26, and a heat insulation chamber 29 defined between the inner container 26 and the outer casing 27, the helium leak rate being 10 -9An adiabatic chamber 29 provided under reduced pressure is provided between the inner container 26 and the outer casing 27 so as to have an airtightness (helium airtightness) of not more than millibar liter / second; two connecting portions that support the inner container 26 and are supported by the outer casing 27 (at least one of these is a sliding connecting portion); a support ring 35 attached at a position spaced from the connecting portion in the adiabatic chamber 29 between the inner container 26 and the outer casing 27; a removable collector 38 that penetrates the outer casing 27 and the inner container 26 in a sealed state; and a neck portion 42 that forms a sealed interface between the collector 38 and the outer casing 27 and between the collector 38 and the inner container 26 and has flexibility and heat insulation properties. The neck portion 42 is formed so as to surround a part of the collector 38, and the neck portion 42 is provided so as to penetrate the adiabatic chamber 29 so as to enable removal of the collector 38 regardless of the pressure in the adiabatic chamber 29.

[0101] The storage and distribution assembly includes an inner container that defines a liquefied gas storage chamber, an outer casing that houses the inner container, a sealed adiabatic chamber defined between the inner container and the outer casing, a removable liquefied gas collector that penetrates the outer casing and the inner container in a sealed state (the collector extends across the diameter or diagonal of the inner container and has a free end near the bottom of the inner container), a liquefied gas duct supplied by the collector, a temporary storage tank that constitutes gasification means for pressurizing the gas supplied by the cryogenic tank device, an upstream valve that is opened for the flow of liquid during the filling stage into the temporary storage tank and is turned on and off so as to be closed during the discharge stage from the temporary storage tank, a downstream valve that is opened for the flow of gas during the discharge stage from the temporary storage tank and is turned on and off so as to be closed other than during the discharge stage, and a pressure reducing valve disposed downstream of the downstream valve. The pressure reducing valve is operated so that the pressure of the gas at the outlet is lower than the pressure in the temporary storage tank at the start of the discharge stage.

Claims

1. A cryogenic tank device of spherical or elongated shape mounted on an aircraft for storing gas, comprising: an inner container (26) defining a liquefied gas storage chamber (28); an outer casing (27) housing the inner container (26), the outer casing (27) being composed of a plurality of removable parts to enable access to the inner container (26), and the outer casing (27) being made of a material resistant to temperatures from less than -60°C to at least +80°C; An adiabatic chamber (29) defined between the inner container (26) and the outer casing (27), the helium leak rate being －９ An adiabatic chamber (29) provided under reduced pressure between the inner container (26) and the outer casing (27) so as to have airtightness such that it is 10 two connecting parts for supporting the inner container (26) and supported by the outer casing (27), at least one of which is a sliding type connecting part; a removable collector (38) penetrating the outer casing (27) and the inner container (26) in a sealed state; a neck part (42) forming a sealed interface between the collector (38) and the outer casing (27) and between the collector (38) and the inner container (26), having flexibility and heat insulation; the neck part (42) is formed to surround a part of the collector (38); the neck part (42) is provided through the heat insulation chamber (29) to enable removal of the collector (38) regardless of the pressure in the heat insulation chamber (29); a cryogenic tank device.

2. The cryogenic tank device according to Claim 1, further comprising: a heat-insulating stopper assembly that is removably attached to the collector (38) and accessible from the outside. The cryogenic tank device is characterized by this.

3. In the cryogenic tank device according to Claim 1 or 2, one of the connecting parts comprises an axial recess provided in the outer casing (27); the axial recess is configured to receive and support an axial protrusion of the inner container (26). The cryogenic tank device is characterized by this.

4. In the cryogenic tank device according to Claim 1 or 2, the outer casing (27) comprises: a frame (30); a plurality of sealed panels (31); a pressure-resistant seal provided between the frame (30) and the panels (31) and / or between the plurality of panels (31). The cryogenic tank device is characterized by this.

5. In the cryogenic tank device according to Claim 4, The frame (30) includes a plurality of rib portions (32) and a plurality of spar portions (33). A cryogenic tank device characterized by this.

6. In the cryogenic tank device according to claim 4, The seal is housed in a groove, and in a free state, protrudes from the groove by a height of less than 10% of the height of the seal. A cryogenic tank device characterized by this.

7. In the cryogenic tank device according to claim 1 or 2, It includes an anti-vibration member provided in the inner container (26) and a reinforcing material provided in the inner container (26). A cryogenic tank device characterized by this.

8. In the cryogenic tank device according to claim 1 or 2, It includes at least one support ring (35) attached at a position spaced apart from the connection portion in the heat insulation chamber (29) between the inner container (26) and the outer casing (27). A cryogenic tank device characterized by this.

9. In the cryogenic tank device according to claim 1 or 2, A hydrogen absorption material is arranged in the heat insulation chamber (29), A hydrogen presence detector is provided in the heat insulation chamber (29). A cryogenic tank device characterized by this.

10. An assembly, The cryogenic tank device according to claim 1 or 2, A temporary storage tank (7) constituting gasification means for pressurizing the gas supplied by the cryogenic tank device, An upstream valve (12) that is opened with respect to the flow of liquid during the filling stage into the temporary storage tank (7) and is closed outside the filling stage, A downstream valve (13, 15) that is opened with respect to the flow of gas during the discharge stage from the temporary storage tank (7) and is closed outside the discharge stage, A compressor (20) arranged downstream of the downstream valve (15), A decompressor (9) arranged downstream of the downstream valve (15), and includes The upstream valve (12) and the downstream valves (13, 15) are closed during the gasification stage, The upstream valve (12) and the downstream valves (13, 15) are configured to be on-off controlled, The compressor (20) is operated so that at the end of the discharge stage, the pressure in the temporary storage tank (7) is lower than the value of the pressure in the cryogenic tank device. The decompressor (9) is operated to make the pressure of the gas at the outlet lower than the pressure in the temporary storage tank (7) at the start of the discharge stage. Assembly.

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