High pressure gas storage device

Abstract

To achieve reduction of the weight.SOLUTION: A high pressure gas storage device includes: a tank 10 forming a shape in which both axial ends of a cylindrical part 11 is closed by a pair of dome parts 12 and configured to store a high pressure gas; a pair of dome-shaped outer shell bodies 20 each of which covers only an area at the dome part 12 side relative to a center part in an axial direction of the cylindrical part 11 of the tank 10 and is disposed forming an air-tight space 15 with an outer surface of the dome part 12; and a fuel pump 40 and a filling valve 45 serving as functional devices which are attached only to the dome parts 12 and disposed so as to face the air-tight space 15.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a high-pressure gas storage device. [Background technology]

[0002] Patent Document 1 discloses a double-shell tank in which an inner tank for storing liquefied gas is surrounded by an outer tank. The inner tank has a capsule shape with both ends of a cylindrical body closed by a pair of hemispherical dome parts. When liquefied gas leaks from the inner tank in a vaporized state, this double-shell tank can prevent the vaporized liquefied gas from being released into the atmosphere by retaining the vaporized liquefied gas in the space between the inner tank and the outer tank. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-152260 A Summary of the Invention [Problem to be solved by the invention]

[0004] The inner tank of this type of double-shell tank is fitted with equipment such as a pump for sending the liquefied gas in the inner tank to the outside, and sensors for electrically detecting the liquid level, temperature, pressure, etc. of the liquefied gas in the inner tank. Liquefied gas is likely to leak from small gaps in the areas where these devices are fitted. The above-mentioned double-shell tank has a structure in which the entire inner tank is covered by the outer tank, which increases the overall weight.

[0005] The present invention was developed in view of the above circumstances, and an object of the present invention is to achieve weight reduction. [Means for solving the problem]

[0006] The high pressure gas storage device of the present disclosure is a tank having a cylindrical portion with both axial ends closed by a pair of dome portions and configured to store high-pressure gas; a pair of dome-shaped outer shells that cover only a region of the tank that is closer to the dome portion than a center portion of the axial direction of the cylindrical portion and are arranged with an airtight space between them and an outer surface of the dome portion; and a functional device attached only to the dome portion and disposed so as to face the airtight space. Effect of the Invention

[0007] This configuration makes it possible to reduce weight. [Brief description of the drawings]

[0008] [Figure 1] Cross-sectional view of the high-pressure gas storage device of the first embodiment [Diagram 2] Partially enlarged cross-sectional view of Fig. 1 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] First, embodiments of the present disclosure will be listed and described. Any combination of the following embodiments without causing any contradiction is also included in the embodiment for carrying out the present invention. The high pressure gas storage device of the present disclosure is (1) A tank having a shape in which both axial ends of a cylindrical portion are closed by a pair of dome portions for storing high-pressure gas, a pair of dome-shaped outer shells covering only the area of ​​the tank that is closer to the dome portion than the axial center of the cylindrical portion and arranged with an airtight space between them and the outer surface of the dome portion, and a functional device attached only to the dome portion and arranged to face the airtight space. With this configuration, it is only the dome portion to which the functional device is attached that needs to be covered with the outer shell as a measure against leakage of high-pressure gas at the attachment site of the functional device. Since there is no need to surround the entire tank with the outer shell, it is possible to reduce the weight.

[0010] (2) In (1), it is preferable that the outer shell body is fixed to both axial ends of the outer circumferential surface of the cylindrical portion, and the pair of outer shell bodies are connected by a connecting member so as not to be separated in the axial direction. According to the configuration of the present disclosure, when the high-pressure gas in the tank leaks into one of the airtight spaces and the pressure in the airtight space increases, a pressing force acts on one of the outer shell bodies in a direction moving away from the dome portion in the axial direction, so that the load on the fixing portion between the outer shell body subjected to the pressing force and the cylindrical portion increases. However, since the outer shell body subjected to the pressing force and the other outer shell body are restricted from moving away from each other in the axial direction by the connecting member, the pressing force acting on one of the outer shell bodies is distributed to the fixing portions of the two outer shell bodies. This reduces the load on the fixing portion between the outer shell body and the cylindrical portion, and the outer shell body can be securely held against the cylindrical portion.

[0011] (3) In (2), it is preferable that the outer shell is configured to include a dome-shaped main body covering the dome portion, a ring-shaped bracket, and a fastening member for fastening the bracket to the opening edge of the dome-shaped main body, and the bracket is fixed to the outer circumferential surface of the cylindrical portion by welding. According to this configuration, after the bracket is fixed to the cylindrical portion, the bracket and the dome-shaped main body can be fixed with the fastening member. The dome-shaped main body can be removed from the tank by releasing the fastening member, making maintenance easy.

[0012] (4) In (1) to (3), it is preferable that the pair of airtight spaces communicate with each other via a communication passage. With this configuration, when the high-pressure gas in the tank leaks into one of the airtight spaces, the gas in that airtight space flows out through the communication passage into the other airtight space, so that the pair of airtight spaces are kept at the same pressure. This makes it possible to prevent the pressure in one of the airtight spaces from increasing excessively when the high-pressure gas leaks.

[0013] <Example 1> A first embodiment of the present invention will be described below with reference to Figs. 1 and 2. In the following description, the F direction in Figs. 1 and 2 is defined as the front. The front-rear direction and the axial direction are used synonymously. The H direction in Figs. 1 and 2 is defined as the up-down direction.

[0014] The high-pressure gas storage device of the first embodiment is configured to include a metal tank 10, a pair of front and rear metal shells 20, a plurality of functional devices 40, 45, a plurality of connecting members 50, and a communication pipe 55. The tank 10 is a capsule-shaped single member having a cylindrical tubular portion 11 with an axis (not shown) oriented in the front-rear direction, and a pair of front and rear dome portions 12. The openings at both front and rear ends of the tubular portion 11 are airtightly closed by the pair of dome portions 12. The inside of the tank 10 functions as a storage space 13 for storing high-pressure gas (liquefied gas or vaporized gas). The high-pressure gas stored in the storage space 13 is, for example, fuel to be supplied to an engine (not shown).

[0015] One outer shell 20 is configured to include one dome-shaped main body 21, one bracket 26, and multiple sets of fastening members 30. The dome-shaped main body 21 is a single component having a dome-shaped covering portion 22 having a substantially hemispherical shape and a flange portion 23. The inner diameter of an opening edge portion 22E of the dome-shaped covering portion 22 is set to a dimension larger than the outer diameter of the cylindrical portion 11 of the tank 10 and the maximum outer diameter of the dome portion 12. In this embodiment 1, the opening edge portion 22E of the dome-shaped covering portion 22 is in the same position as the opening edge portion 21E of the dome-shaped main body 21.

[0016] The flange portion 23 has an annular shape and extends radially outward from the opening edge portion 22E of the dome-shaped cover portion 22 over the entire circumference. As shown in FIG. 2, a plurality of mounting holes 24 are formed in a region of the flange portion 23 close to the opening edge portion 22E of the dome-shaped cover portion 22 in the radial direction. Each mounting hole 24 penetrates the flange portion 23 in the front-rear direction. The mounting holes 24 are arranged at intervals in the circumferential direction on a circumference concentric with the dome-shaped cover portion 22 and the flange portion 23. A plurality of connecting holes 25 are formed in a region of the flange portion 23 on the outer circumferential side of the mounting holes 24 in the radial direction. Each connecting hole 25 penetrates the flange portion 23 in the front-rear direction. The connecting holes 25 are arranged at intervals in the circumferential direction on a circumference concentric with the dome-shaped cover portion 22 and the flange portion 23.

[0017] The bracket 26 is a single plate-like component that is concentric with the dome-shaped main body 21 and has an annular shape. The inner diameter of the bracket 26 is set to be the same as the outer diameter of the cylindrical portion 11 or slightly larger than the outer diameter of the cylindrical portion 11. The bracket 26 is formed with a plurality of support holes 27. Each support hole 27 penetrates the bracket 26 in the front-rear direction. The support holes 27 are arranged at intervals in the circumferential direction on a single circumference that is concentric with the dome-shaped main body 21 and the bracket 26. The diameter of a circle that passes through the centers of the support holes 27 is the same as the diameter of a circle that passes through the centers of the mounting holes 24. The support holes 27 and the mounting holes 24 are arranged at the same pitch in the circumferential direction.

[0018] The bracket 26 constituting the front shell body 20 and the bracket 26 constituting the rear shell body 20 are both coaxially fixed to the tank 10 by a welded portion 28. The front bracket 26 is disposed at a position forward of the axial center of the outer periphery of the cylindrical portion 11. As shown in FIG. 1, the front bracket 26 is fitted to a position slightly rearward of the foremost end 11F of the cylindrical portion 11 (position closer to the axial center) and fixed to the outer periphery of the tank 10 by welding. The rear bracket 26 is disposed at a position rearward of the axial center of the outer periphery of the cylindrical portion 11. The rear bracket 26 is fitted to a position slightly forward of the rearmost end 11R of the cylindrical portion 11 (position closer to the axial center) and fixed to the outer periphery of the tank 10 by welding. The gap between the outer periphery of the tank 10 (cylindrical portion 11) and the inner periphery of the bracket 26 is airtightly sealed by the fillet of the welded portion 28.

[0019] The dome-shaped main body 21 is attached to the bracket 26 by multiple sets of fastening members 30. Each set of fastening members 30 is composed of one fastening bolt 31 and one fastening nut 32. The front dome-shaped main body 21 is disposed on the bracket 26 with the flange portion 23 overlapping from the front. At this time, the dome-shaped main body 21 is positioned with respect to the bracket 26 so that the multiple mounting holes 24 and the multiple support holes 27 are individually coaxially overlapping.

[0020] With the bracket 26 positioned in this manner, the fastening bolts 31 are inserted through the support holes 27 and the mounting holes 24 from the rear of the bracket 26. When the fastening nuts 32 are screwed onto the tips of the fastening bolts 31 protruding forward of the flange portion 23 and tightened, the dome-shaped main body 21 is fixed to the bracket 26. A seal member (not shown) provides an airtight seal between the front surface of the bracket 26 and the rear surface of the flange portion 23. When the dome-shaped main body 21 is fixed to the bracket 26, the assembly of the outer shell 20 is completed, and at the same time, the assembly of the outer shell 20 to the tank 10 is completed. The rear dome-shaped main body 21 is fixed to the rear bracket 26 in the same manner as the front dome-shaped main body 21.

[0021] When the outer shell bodies 20 are attached to the tank 10, only a portion of the outer surface of the tank 10 is covered by the pair of outer shell bodies 20. The pair of outer shell bodies 20 cover only the front and rear ends of the cylindrical portion 11 and the entire dome portion 12. The exposed area of ​​the tank 10 that is not covered by the outer shell bodies 20 (the axial center of the cylindrical portion 11) is defined as an exposed area 14. The area of ​​the outer surface of the tank 10 that is covered by the outer shell bodies 20 and the space partitioned by the outer shell bodies 20 are defined as an airtight space 15. The pair of front and rear airtight spaces 15 are kept airtight with respect to the external space of the high-pressure gas storage device and the inside of the storage space 13 of the tank 10.

[0022] The functional devices are devices attached to the tank 10 so as to face the inside of the tank 10 (storage space 13) and the outside of the tank 10. All of the functional devices provided in the high-pressure gas storage device of this embodiment 1 are attached only to areas of the tank 10 other than the exposed area 14, and are arranged so as to face the airtight space 15. The high-pressure gas storage device of this embodiment 1 is equipped with a fuel pump 40 and a filling valve 45 as functional devices, and further includes a safety valve (not shown), various sensors (not shown), etc.

[0023] The fuel pump 40 is a device for supplying fuel (high pressure gas) stored in the tank 10 to the vehicle engine (not shown). The fuel pump 40 is attached in an airtight manner penetrating the front dome portion 12 and the front dome-shaped cover portion 22. The suction port 41 of the fuel pump 40 is disposed in the storage space 13. The discharge port 42 of the fuel pump 40 is disposed outside the outer shell 20. A portion of the fuel pump 40 is disposed in the airtight space 15.

[0024] The filling valve 45 is a device for filling the tank 10 with fuel before the rear shell 20 is attached to the tank 10. The filling valve 45 is attached to the rear dome portion 12 in an airtight manner so as to penetrate therethrough. A filling port 46 of the filling valve 45 is disposed in the airtight space 15. An inlet port 47 of the filling valve 45 is disposed in the storage space 13.

[0025] The front shell body 20 and the rear shell body 20 are connected by multiple sets of connecting members 50 so that they are not separated in the front-rear direction. Each set of connecting members 50 is configured to include one connecting bar 51 that is elongated in the front-rear direction and a pair of connecting nuts 53. Male threaded portions 52 are formed on both front and rear ends of the connecting bar 51. The front end of the connecting bar 51 is inserted into the connecting hole 25 of the front flange portion 23, and the connecting nut 53 is screwed into the male threaded portion 52 that protrudes forward of the flange portion 23.

[0026] The rear end of the connecting bar 51 is inserted into the connecting hole 25 of the rear flange portion 23, and a connecting nut 53 is screwed into the male thread portion 52 protruding rearward of the flange portion 23. By tightening either the front or rear connecting nut 53, the front and rear connecting nuts 53 press the front and rear flange portions 23 closer to each other in the axial direction. This pressing of the two connecting nuts 53 restricts the front and rear outer shell bodies 20 from relative displacement in the direction separating them in the axial direction.

[0027] The communicating pipe 55 is disposed outside the tank 10 and the outer shell 20 so as to extend in the front-rear direction as a whole. The front end of the communicating pipe 55 is airtightly attached to the front dome-shaped cover portion 22. The rear end of the communicating pipe 55 is airtightly attached to the rear dome-shaped cover portion 22. The inside of the communicating pipe 55 functions as a communicating passage 56 that communicates between the front airtight space 15 and the rear airtight space 15.

[0028] Next, the operation and effect of the present embodiment 1 will be described. The portion of the tank 10 through which the fuel pump 40 and the filling valve 45 penetrate is made airtight by a sealing member (not shown). However, there is a concern that the fuel in the storage space 13 may be exposed into the airtight space 15 due to deterioration of the sealing member or the like. However, the portion of the tank 10 to which the fuel pump 40 and the filling valve 45 are attached is covered in an airtight state by the outer shell 20, so that the fuel (vaporized gas) leaking from the tank 10 will not be released into the atmosphere.

[0029] Furthermore, if vaporized gas leaks only into either the front or rear airtight space 15, the pressure in the airtight space 15 on the leaking side will rise. When the pressure rises, the outer shell body 20 receives a pressing force in a direction moving it away from the tank 10 (dome portion 12) in the axial direction. This pressing force acts as a shear force on the welded portion 28 that fastens the tank 10 and the bracket 26. Therefore, there is a concern that the welded portion 28 will be destroyed and the bracket 26 (outer shell body 20) will come off the tank 10.

[0030] However, in the present embodiment 1, the gas (air and vaporized gas) in the leaking airtight space 15 flows into the non-leaking airtight space 15 by passing through the communication passage 56, so that the pressures in the front airtight space 15 and the rear airtight space 15 are kept at the same pressure. The pressures in the front and rear airtight spaces 15 at this time are kept lower than the pressure in the leaking airtight space 15 when the front and rear airtight spaces 15 are not connected to each other. Therefore, the shear force acting on the welded portion 28 is kept low, and damage to the welded portion 28 can be prevented.

[0031] In addition, the dome-shaped main bodies 21 of the front and rear outer shells 20 are held by the connecting members 50 in a state in which they are not separated from each other in the front-rear direction. Therefore, even if the pressure in the front and rear airtight spaces 15 increases, no force is applied from the dome-shaped main body 21 to the bracket 26 in a direction that causes the dome-shaped main bodies 21 to separate from each other in the axial direction. This makes it possible to prevent damage to the welded portion 28 that would otherwise be caused by the front and rear dome-shaped main bodies 21 separating from each other in the axial direction.

[0032] The high-pressure gas storage device of the first embodiment includes a tank 10 for storing high-pressure gas, a pair of front and rear shell bodies 20, and a functional device (a fuel pump 40 and a filling valve 45). The tank 10 has a shape in which both axial ends of a cylindrical portion 11 are closed by a pair of dome portions 12. The pair of shell bodies 20 are dome-shaped and cover only the area of ​​the tank 10 on the dome portion 12 side from the axial center of the cylindrical portion 11. The shell body 20 is disposed with an airtight space 15 between it and the outer surface of the dome portion 12. The functional device (the fuel pump 40 and the filling valve 45) is attached only to the dome portion 12 and disposed so as to face the airtight space 15.

[0033] With this configuration, in order to prevent leakage of high-pressure gas at the attachment points of the fuel pump 40 and the filling valve 45, it is only the dome portion 12 to which the fuel pump 40 and the filling valve 45 are attached that needs to be covered with the outer shell 20. Since the high-pressure gas storage device of the first embodiment does not need to surround the entire tank 10 with the outer shell 20, it is possible to reduce the weight.

[0034] The outer shell body 20 is fixed to both ends in the axial direction on the outer circumferential surface of the cylindrical portion 11. When the high-pressure gas in the tank 10 leaks into one of the airtight spaces 15 and the pressure in the airtight space 15 rises, a pressing force acts on one of the outer shell bodies 20 in a direction moving away from the dome portion 12 in the axial direction, and the load on the fixing portion between the outer shell body 20 receiving the pressing force and the cylindrical portion 11 increases. However, since the pair of outer shell bodies 20 (the outer shell body 20 receiving the pressing force and the other outer shell body 20) are connected by the connecting member 50 so as not to be separated in the axial direction, the pressing force acting on one of the outer shell bodies 20 is distributed to the fixing portions of the two outer shell bodies 20. This reduces the load on the fixing portion between the outer shell body 20 and the cylindrical portion 11, and the outer shell body 20 can be securely held against the cylindrical portion 11.

[0035] The outer shell 20 is configured to include a dome-shaped main body 21 that covers the dome portion 12, a ring-shaped bracket 26, and a fastening member 30 that fastens the bracket 26 to the opening edge portion 21E of the dome-shaped main body 21. The bracket 26 is fixed to the outer circumferential surface of the cylindrical portion 11 by welding. With this configuration, after the bracket 26 is fixed to the cylindrical portion 11, the bracket 26 and the dome-shaped main body 21 can be fixed with the fastening member 30. The dome-shaped main body 21 can be removed from the tank 10 by releasing the fastening member 30, making maintenance easy.

[0036] The pair of airtight spaces 15 communicate with each other via a communication passage 56. When the high-pressure gas in the tank 10 leaks into one of the airtight spaces 15, the gas in that airtight space 15 flows out through the communication passage 56 to the other airtight space 15, so that the pair of airtight spaces 15 are kept at the same pressure. This makes it possible to prevent the pressure in one of the airtight spaces 15 from increasing excessively when the high-pressure gas leaks.

[0037] <Other Examples> The present invention is not limited to the embodiments described above and illustrated in the drawings, and the following embodiments are also included within the technical scope of the present invention. The exterior body is not limited to a two-part structure consisting of a dome-shaped main body and a bracket, but may be a single part in which the dome-shaped main body and the bracket are integrated. The dome-shaped body and the bracket may be secured together by means other than fasteners. The connecting member is not limited to being shaft-shaped, but may be plate-shaped. The connecting member is not limited to connecting the dome-shaped main bodies constituting the outer shell, but may connect brackets together. The pair of outer shells may not be connected by a connecting member. The connecting member may be tubular. In this case, the connecting member may have a function of connecting the airtight spaces to each other. The pair of airtight spaces may not be in communication with each other. The material of the tank is not limited to metal, but may be synthetic resin. The material of the outer shell is not limited to metal, but may be synthetic resin. [Explanation of symbols]

[0038] 10. Tank 11...Cylindrical part 12…Dome section 15...Airtight space 20…External shell 21…Dome-shaped body 21E…Opening edge of dome-shaped body 26…Bracket 28…Welded section 30...Fastening member 40...Fuel pump (functional device) 45...Filling valve (functional device) 50...Connecting member 56…Communication path

Claims

1. a tank having a cylindrical portion with both axial ends closed by a pair of dome portions and configured to store high-pressure gas; a pair of dome-shaped outer shells that cover only a region of the tank that is closer to the dome portion than a center portion of the axial direction of the cylindrical portion and are arranged with an airtight space between them and an outer surface of the dome portion; a functional device attached only to the dome portion and disposed so as to face the airtight space.

2. The outer shell is fixed to both axial ends of an outer circumferential surface of the cylindrical portion, 2. The high-pressure gas storage device according to claim 1, wherein the pair of outer shells are connected by a connecting member so as to be inseparable in the axial direction.

3. the outer shell body is configured to include a dome-shaped main body covering the dome portion, a ring-shaped bracket, and a fastening member for fixing the bracket to an opening edge portion of the dome-shaped main body, 3. The high-pressure gas storage device according to claim 2, wherein the bracket is fixed to the outer peripheral surface of the cylindrical portion by welding.

4. 4. The high-pressure gas storage device according to claim 1, wherein the pair of airtight spaces communicate with each other via a communication passage.

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