pressure accumulator

Abstract

The pressure accumulator has a metal cylinder that vaporizes and stores liquefied gas in an internal storage space, a cover that forms a through hole for a pipe to pass through, fixes the pipe passing through the through hole, and blocks the open end of the cylinder in a state where a gap is provided between the inner peripheral surface of the cylinder and the cover and communicates with the storage space of the cylinder, a sealing structure portion that is provided between the outer peripheral portion of the cover and the inner peripheral portion of the cylinder, and fills at least a portion of the gap, and a fixing member that is provided at the open end of the cylinder, is threadedly fastened to the inner peripheral surface of the cylinder, and supports and fixes the cover from the outside.

Description

TECHNICAL FIELD

[0001] The present application relates to a pressure accumulator that stores a gasified liquefied gas. BACKGROUND

[0002] Various pressure accumulators that store a gasified liquefied gas in the inside have been known in the past and have been put into practical use. In general, liquefied hydrogen that is transported by a liquefied hydrogen transport vehicle and stored in a storage tank is gasified by a gasifier, compressed by a compressor to form high pressure, and then injected into the inside of a pressure accumulator through a pipe. For example, the hydrogen gas pressure accumulator disclosed in Patent Document 1 has a structure in which a steel cylindrical cylinder portion that stores a gasified liquefied gas in the inside, a lid portion that can open and close the both end portions of the cylindrical cylinder portion, and a screwed-in portion that fixes the lid portion to the cylindrical cylinder portion.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT DOCUMENTS

[0005] Patent Document 1: Japanese Patent Application Publication No. 2019-82188 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] However, it is considered to be configured so that a liquefied gas at an extremely low temperature is injected from the outside to the inside through a pipe, the liquefied gas is gasified in the inside and stored in the pressure accumulator, and thus a gasifier is not needed. However, in the hydrogen gas pressure accumulator disclosed in Patent Document 1, the temperature of the liquefied hydrogen is about -260°C, which is lower than the temperature of about -30°C that the cylindrical cylinder portion can withstand, and thus the lid portion becomes low temperature due to heat conduction of the liquefied hydrogen at an extremely low temperature flowing through the pipe, and the cylindrical cylinder portion that is heat-conducted from the lid portion also becomes low temperature, which can cause brittle fracture of the cylindrical cylinder portion.

[0008] The present application has been achieved in order to solve the above problems, and aims to provide a pressure accumulator that can gasify and store a liquefied gas without causing brittle fracture of a cylinder portion even if a liquefied gas at an extremely low temperature is injected from the outside to the inside through a pipe.

[0009] MEANS FOR SOLVING THE PROBLEMS

[0010] The present application relates to a pressure accumulator which allows a liquefied gas at an extremely low temperature to be injected from the outside through a pipe into the inside so as to be vaporized and stored, the pressure accumulator having: a cylindrical body made of metal which vaporizes and stores the liquefied gas in an internal storage space; a lid body which is formed with a through-hole through which the pipe is inserted, fixes the pipe inserted through the through-hole, and blocks an open end portion of the cylindrical body in a state in which a gap is provided between an inner peripheral surface of the cylindrical body and the lid body so as to communicate with the storage space of the cylindrical body; a sealing structure portion which is provided between an outer peripheral portion of the lid body and an inner peripheral portion of the cylindrical body, and fills at least a portion of the gap; and a fixing member which is provided at the open end portion of the cylindrical body, is threadedly fastened to the inner peripheral surface of the cylindrical body, and supports and fixes the lid body from the outside.

[0011] Effects of the Invention

[0012] According to the present application, since the gap is provided between the outer peripheral portion of the lid body and the inner peripheral portion of the cylindrical body, and at least a portion of the gap is filled with the sealing structure portion, the gap functions as a heat insulating layer, heat conduction from the lid body to the cylindrical body can be suppressed, and thus brittle fracture of the cylindrical body can be suppressed. Therefore, the liquefied gas at an extremely low temperature can be injected from the outside through the pipe into the inside so as to be vaporized and stored. BRIEF DESCRIPTION OF DRAWINGS

[0013] [ Figure 1 ] is a pressure accumulator according to Embodiment 1, and is a cross-sectional view schematically showing an internal structure of one end side.

[0014] [ Figure 2 ] is a modification of the pressure accumulator according to Embodiment 1, and is a cross-sectional view schematically showing an internal structure of one end side.

[0015] [ Figure 3 ] is a pressure accumulator according to Embodiment 2, and is a cross-sectional view schematically showing an internal structure of one end side.

[0016] [ Figure 4 ] is a modification of the pressure accumulator according to Embodiment 2, and is a cross-sectional view schematically showing an internal structure of one end side.

[0017] [ Figure 5 ] is a pressure accumulator according to Embodiment 3, and is a cross-sectional view schematically showing an internal structure of one end side.

[0018] [ Figure 6 ] is a pressure accumulator according to Embodiment 3, and is an explanatory view schematically showing an end surface of an outer lid body. DETAILED DESCRIPTION

[0019] Hereinafter, embodiments will be described with reference to the accompanying drawings. It should be noted that the same or equivalent parts in each drawing are given the same reference numerals, and their descriptions are appropriately omitted or simplified. Furthermore, the shape, size, and arrangement of the structures depicted in each drawing can be appropriately modified within the scope of this invention.

[0020] Implementation method 1.

[0021] Figure 1 This is a schematic cross-sectional view of the internal structure of the accumulator according to Embodiment 1, showing one end side. The accumulator 100 of Embodiment 1 allows extremely low-temperature liquefied gas to be injected from the outside into the interior through piping 200, thereby vaporizing and storing the liquefied gas. In Embodiment 1, liquefied hydrogen is used as an example of a liquid gas for explanation. Extremely low-temperature liquefied hydrogen refers to, for example, around -260°C. It should be noted that, in addition to liquefied hydrogen, the liquid gas can also be, for example, liquid nitrogen, liquid helium, etc. When the liquid gas is liquefied hydrogen, the accumulator 100 is installed, for example, in a hydrogen station that supplies hydrogen to vehicles, etc.

[0022] (Accumulator 100)

[0023] like Figure 1 As shown, the accumulator 100 has a metal cylinder 1, a cover 2 that blocks the open end of the cylinder 1, a sealing structure 3 disposed between the outer periphery of the cover 2 and the inner periphery of the cylinder 1, a fixing component 4 that supports and fixes the cover 2 from the outside, and a temperature detection mechanism 5.

[0024] (Cylinder 1)

[0025] The cylinder 1 contains a storage space 10 within which liquefied hydrogen is vaporized and stored. The inner wall of the accumulator 100 is the part that comes into contact with the liquefied hydrogen and the hydrogen gas. Extremely low-temperature liquefied gas is injected into the storage space 10 of the cylinder 1 from the outside via piping 200. The piping 200 is, for example, made of austenitic stainless steel. This is because austenitic stainless steel exhibits excellent resistance to the brittleness of liquid hydrogen and ensures strength at extremely low temperatures. The hydrogen stored in the storage space 10 of the cylinder 1 is supplied to vehicles, etc., via piping connected to the outside.

[0026] The cylinder body 1 is formed of, for example, low alloy steel. The low alloy steel refers to, for example, chromium-molybdenum steel, nickel-chromium-molybdenum steel, manganese-chromium steel, manganese steel, or boron-added steel. The cylinder body 1 is in a cylindrical shape with both ends open, and an internally threaded portion 11 is formed on the inner peripheral surface of both end portions. Note that the cylinder body 1 can also be in a bottomed cylindrical shape with only one end open. In addition, the cylinder body 1 is not limited to a cylindrical shape, and can be in another shape such as a square tube shape. In addition, the outer surface of the cylinder body 1 can be covered with CFRP (Carbon Fiber Reinforced Plastics) as a material other than metal. Note that, from the viewpoint of gasification efficiency, the ratio of the CFRP layer to the wall thickness of the cylinder body 1 (the thickness of the CFRP layer / the thickness of the cylinder body 1) is preferably 50% or less, and more preferably 25% or less. This is because if the CFRP layer is too thick, the heat insulation effect is significant, and thus the gasification efficiency of the liquefied hydrogen decreases.

[0027] (Cover body 2)

[0028] The cover body 2 plugs the open end portion of the cylinder body 1. The cover body 2 has an inner cover body 20 formed of austenitic stainless steel and disposed on the storage space 10 side of the cylinder body 1, and an outer cover body 21 formed of low alloy steel and disposed on the fixing member 4 side of the cylinder body 1. The inner cover body 20 is formed with a through-hole 20a through which a pipe 200 passes, and the pipe 200 passing through the through-hole 20a is fixed. The outer cover body 21 is formed with a through-hole 21a through which the pipe 200 passes.

[0029] The inner cover body 20 faces the storage space 10 of the cylinder body 1, and is always in a state of being exposed to liquid hydrogen at an extremely low temperature, but since it is formed of austenitic stainless steel, it has excellent brittleness against liquid hydrogen and can ensure strength against an extremely low temperature. Note that as long as the inner cover body 20 has excellent brittleness against liquid hydrogen and can withstand an extremely low temperature, it can also be made of another material. As an example, the length of the inner cover body 20 in the pipe axis direction X of the cylinder body 1 is about 30 mm. This is because as long as the strength against liquid hydrogen is about 30 mm, it is sufficient. However, the length of the inner cover body 20 is not limited to about 30 mm, and can be appropriately changed and designed according to the size and shape of the cylinder body 1.

[0030] In addition, the inner cover body 20 has a threaded fastening portion 22 that fixes the pipe 200 passing through the through-hole 20a by threaded fastening. Specifically, it is configured so that an internal thread is formed on the inner peripheral portion of the through-hole 20a of the inner cover body 20, and an external thread that is fastened to the internal thread of the inner cover body 20 is formed on the outer peripheral portion of the pipe 200. By threadedly fastening the inner cover body 20 and the pipe 200, the pipe 200 can be reliably fixed against the internal pressure of hydrogen gas stored in the storage space 10 of the cylinder body 1.

[0031] A seal member 6 is provided between the inner peripheral portion of the inner lid 20 and the outer peripheral portion of the pipe 200. This is to prevent the hydrogen gas stored in the storage space 10 of the cylinder 1 from leaking to the outside through the space between the inner peripheral portion of the inner lid 20 and the outer peripheral portion of the pipe 200. As an example, the seal member 6 is an O-ring. However, the seal member 6 is not limited to an O-ring, and can be another member as long as it can prevent the hydrogen gas stored in the storage space 10 of the cylinder 1 from leaking to the outside through the space between the inner peripheral portion of the inner lid 20 and the outer peripheral portion of the pipe 200.

[0032] The inner lid 20 is inserted into the open end portion of the cylinder 1 in a state where a gap S communicating with the storage space 10 of the cylinder 1 is provided between the inner lid 20 and the inner peripheral surface of the cylinder 1. The gap S is, for example, about 0.5 mm, and is provided in the pipe axial direction X of the cylinder 1. By allowing the gap S to function as a thermal insulation layer, it is possible to suppress the temperature of the cylinder 1 from decreasing due to the heat conduction of the pipe 200 through which the liquid hydrogen at an extremely low temperature passes, to the inner lid 20 at a low temperature. In addition, by providing the gap S, it is possible to insert the inner lid 20 into the open end portion of the cylinder 1.

[0033] The outer lid 21 is provided in order to increase the strength against the internal pressure of the hydrogen gas in the inside of the cylinder 1. This is because the inner lid 20 having a length of about 30 mm in the pipe axial direction X is sometimes insufficient in the strength against the internal pressure of the hydrogen gas. The outer lid 21 is formed of, for example, low-alloy steel such as chromium-molybdenum steel, nickel-chromium-molybdenum steel, manganese-chromium steel, manganese steel, or boron-added steel. The low-alloy steel is lower in cost than the austenite-based stainless steel, and thus can contribute to the reduction of the manufacturing cost. Note that the outer lid 21 is not limited to low-alloy steel, and can be formed of another material as long as it can increase the strength against the internal pressure of the hydrogen gas stored in the storage space 10 of the cylinder 1.

[0034] A thermal insulation member 7 is provided between the inner lid 20 and the outer lid 21. This is to prevent the heat conduction from the inner lid 20 to the outer lid 21. In addition, a thermal insulation member 8 is also provided between the outer lid 21 and the pipe 200. This is to prevent the heat conduction of the extremely low temperature of the pipe 200 through which the liquid hydrogen at an extremely low temperature passes, to the outer lid 21. This is because if the outer lid 21 of the low-alloy steel decreases in temperature due to the heat conduction of the extremely low temperature, it can cause brittle fracture. Note that as an example, the materials of the thermal insulation members 7 and 8 are ceramics.

[0035] (Seal structure portion 3)

[0036] The sealing structure portion 3 is provided between the outer peripheral portion of the inner lid body 20 and the inner peripheral portion of the cylinder body 1, and fills at least a portion of the gap S. As an example, the sealing structure portion 3 is a sealing material made of resin or metal such as an O-ring. By providing the sealing structure portion 3, it is possible to prevent the hydrogen gas stored in the storage space 10 of the cylinder body 1 from leaking to the outside through the gap S. Note that filling at least a portion of the gap S means that it can be the entire gap S or a portion of the gap S. Further, as shown in the drawing, a portion of the gap S is preferably the end portion on the side of the storage space 10 of the cylinder body 1, and for example, can be the end portion on the side of the outer lid body 21 or the middle portion. Further, the sealing structure portion 3 is not limited to an O-ring, and can be another member as long as it can prevent the hydrogen gas stored in the storage space 10 of the cylinder body 1 from flowing to the gap S between the outer peripheral portion of the inner lid body 20 and the inner peripheral portion of the cylinder body 1. For example, it can be a member such as a metal hollow O-ring that can be sealed by a combination of metal and resin. Note that in the case of using a resin-made O-ring, it is preferable to use a resin with a cold resistance limit temperature of -30°C or lower, and more preferably -50°C or lower.

[0037] (Fixing member 4)

[0038] The fixing member 4 is provided at the opening end portion of the cylinder body 1, and is threadedly fastened to the inner peripheral surface of the cylinder body 1 to support and fix the lid body 2 from the outside of the storage space 10. Specifically, the fixing member 4 is a gland nut in which an outer threaded portion that is threadedly fastened to the inner threaded portion 11 of the cylinder body 1 is formed on the outer peripheral surface. The fixing member 4 is fixed to the cylinder body 1 in the tube axis direction X by threadedly fastening. The fixing member 4 can support the lid body 2 by abutting the end surface on one side against the outer surface of the outer lid body 21 with respect to the lid body 2, and the aforementioned lid body 2 is a lid body on which the axial force of the high-pressure hydrogen gas stored in the storage space 10 acts in the tube axis direction X. The hollow hole of the fixing member 4 is passed through by the pipe 200. The thickness of the fixing member 4 in the radial direction can be arbitrarily set. However, since the fixing member 4 is a structure that supports the pressure received by the inner lid body 20, if the wall thickness in the radial direction is too thin, the lid body 2 cannot be sufficiently supported. Therefore, the thickness of the fixing member 4 in the radial direction is preferably a wall thickness that can ensure support of an area of 40% or more with respect to the area of the inner lid body 20 that receives pressure, and more preferably a wall thickness that can ensure support of an area of 60% or more. As an example, if the diameter of the inner lid body 20 is 300 mm, the area of the inner lid body 20 that receives pressure is 70,650 mm 2 . Note that the aforementioned area of the inner lid body 20 is calculated including the portion through which the pipe 200 passes, but in reality, it is desirable to calculate excluding the portion through which the pipe 200 passes. On the other hand, if the wall thickness of the fixing member 4 is 50 mm, the area supported by the fixing member 4 is 39,250 mm 2In this case, the fixed member 4 is able to ensure an area of 56% with respect to the area of the inner lid 20 subjected to pressure.

[0039] (Temperature detecting mechanism 5)

[0040] The temperature detecting mechanism 5 is, for example, a thermocouple, and detects the temperature of hydrogen stored in the storage space 10 of the cylinder 1 or the temperature of the inner lid 20. In the accumulator 100 according to Embodiment 1, the temperature of hydrogen stored in the inside of the cylinder 1 or the temperature of the inner lid 20 is monitored using the temperature detecting mechanism 5. In the accumulator 100, the condition of liquid hydrogen injected from the pipe 200 is determined based on the detected value of the temperature detecting mechanism 5. The condition of liquid hydrogen refers to flow rate, flow velocity, injection time, and the like. The accumulator 100 is provided with a control section configured to determine the condition of liquid hydrogen based on the detected value of the temperature detecting mechanism 5, and thereby adjust the flow rate of liquefied hydrogen or the like through the pipe 200. Note that it is desirable that the accumulator 100 be provided with the temperature detecting mechanism 5, but it is not necessarily required, and can be omitted.

[0041] Figure 2 is a modification of the accumulator according to Embodiment 1, and is a cross-sectional view schematically showing the internal structure of the one end side. With respect to Figure 1 The inner lid 20 of the accumulator 100 shown in FIG. 1 has a threaded fastening portion 22 that fastens the pipe 200 passing through the through-hole 20a by threaded fastening, and Figure 2 The accumulator 100A shown in FIG. 2 is configured such that the inner lid 20 has a welded fastening portion 23 that fastens the pipe 200 passing through the through-hole 20a by welding. The welded fastening portion 23 can be provided to the entire body along the pipe axis direction X, or can be provided to only a part. In this case, since the inner peripheral portion of the inner lid 20 and the outer peripheral portion of the pipe 200 are completely blocked, it is not necessary to provide the sealing member 6 shown in FIG. 1. Figure 1

[0042] However, considering that a liquefied gas at an extremely low temperature is injected from the outside to the inside through the pipe 200, and the liquefied gas is vaporized in the inside and stored in the accumulator 100, so that a vaporizer is not required. However, since the cylinder 1 can only withstand, for example, around -30°C, and the temperature of liquid hydrogen is, for example, around -260°C, if liquid hydrogen is injected into the accumulator 100, the lid 2 becomes low temperature due to heat conduction of the liquid hydrogen at an extremely low temperature flowing through the pipe 200, and the cylinder 1 from which heat is conducted from the lid 2 also becomes low temperature, so that brittle fracture of the cylinder 1 can occur.

[0043] ​Therefore, as described above, the pressure accumulator 100 according to the present embodiment 1 has: a cylinder 1 made of metal, which vaporizes and stores liquefied gas in an internal storage space 10; and a lid 2, which is formed with through-holes 20a and 21a through which pipes 200 pass, fixes the pipes 200 passing through the through-holes 20a and 21a, and plugs the open end of the cylinder 1 in a state in which a gap S communicating with the storage space 10 of the cylinder 1 is formed between the inner peripheral surface of the cylinder 1. In addition, there are provided: a seal structure portion 3, which is provided between the outer peripheral portion of the lid 2 and the inner peripheral portion of the cylinder 1, and fills at least a part of the gap S; and a fixing member 4, which is provided at the open end of the cylinder 1, is threadedly fastened to the inner peripheral surface of the cylinder 1, and supports and fixes the lid 2 from the outside.

[0044] Thus, since the pressure accumulator 100 according to the present embodiment 1 is provided with the gap S between the outer peripheral portion of the lid 2 and the inner peripheral portion of the cylinder 1, and at least a part of the gap S is filled with the seal structure portion 3, the gap S functions as a heat insulating layer, and heat conduction from the lid 2 to the cylinder 1 can be suppressed. That is, the situation in which the cylinder 1 is cooled by the lid 2, which is cooled by the pipes 200 through which liquefied hydrogen at an extremely low temperature passes, can be suppressed, and thus the brittle fracture of the cylinder 1 can be suppressed. Therefore, the pressure accumulator 100 according to the present embodiment 1 can inject liquefied gas at an extremely low temperature from the outside through the pipes 200 into the inside, and thus vaporize and store the liquefied gas.

[0045] In addition, the lid 2 has a thread fastening portion 22 that threadedly fastens the pipes 200 passing through the through-holes 20a and 21a. A seal member 6 that plugs the gap between the inner peripheral portion of the lid 2 and the outer peripheral portion of the pipes 200 is provided therebetween. Therefore, the pipes 200 can be reliably fixed with respect to the internal pressure of hydrogen gas stored in the storage space 10 of the cylinder 1. In addition, the situation in which hydrogen gas stored in the storage space 10 of the cylinder 1 leaks to the outside through the gap between the inner peripheral portion of the lid 20 and the outer peripheral portion of the pipes 200 on the inside can be prevented.

[0046] The lid 2 has an inner lid 20 formed of austenitic stainless steel and disposed on the storage space 10 side of the cylinder 1, and an outer lid 21 formed of low alloy steel and disposed on the fixing member 4 side. Therefore, the inner lid 20 faces the storage space 10 of the cylinder 1, and is always in a state of being exposed to liquefied hydrogen at an extremely low temperature, but since it is formed of austenitic stainless steel, the brittleness with respect to liquefied hydrogen is excellent, and the strength with respect to an extremely low temperature can be ensured. In addition, the outer lid 21 can improve the strength with respect to the internal pressure of hydrogen gas in the inside of the cylinder 1, and since low alloy steel, which is less expensive than austenitic stainless steel, is used, the reduction of manufacturing costs can be facilitated.

[0047] Heat insulating members 7 and 8 are provided between the inner cover 20 and the outer cover 21, and between the outer cover 21 and the pipe 200, respectively. Therefore, heat conduction from the inner cover 20 to the outer cover 21 can be prevented, and the case where the extremely low temperature of the pipe 200 through which the liquid hydrogen at an extremely low temperature passes is conducted to the outer cover 21 can be prevented, so that the embrittlement damage of the outer cover 21 caused by the temperature decrease can be prevented.

[0048] The pressure accumulator 100 and 100A according to Embodiment 1 has a temperature detecting mechanism 5 that detects the temperature of the gaseous liquefied gas stored in the storage space 10 of the cylinder 1, or the temperature of the cover 2. Therefore, in the pressure accumulator 100 and 100A according to Embodiment 1, the temperature of the hydrogen gas stored in the inside of the cylinder 1, or the temperature of the inner cover 20 can be monitored using the temperature detecting mechanism 5, and the condition of the liquid hydrogen injected from the pipe 200 can be determined based on the detection value of the temperature detecting mechanism 5.

[0049] Embodiment 2.

[0050] Next, based on Figure 3 The pressure accumulator 101 according to Embodiment 2 will be described. Figure 3 is a sectional view schematically showing the internal structure of the one end side of the pressure accumulator according to Embodiment 2. Note that the same reference numerals are given to the same constituent elements as those of the pressure accumulator 100 described in Embodiment 1, and the description thereof will be appropriately omitted.

[0051] (Cover 2)

[0052] The cover 2 of the pressure accumulator 101 according to Embodiment 2 is different from the cover 2 of the pressure accumulator 100 described in Embodiment 1. The cover 2 of the pressure accumulator 101 according to Embodiment 2 is formed only of an austenitic stainless steel.

[0053] The cover 2 has a threaded fastening portion 22 that fixes the pipe 200 passing through the through hole 2a by threaded fastening. Specifically, the threaded fastening portion 22 is configured such that an internal thread is formed in the inner peripheral portion of the through hole 2a of the cover 2, and an external thread that is fastened to the internal thread of the cover 2 is formed in the outer peripheral portion of the pipe 200. Since the threaded fastening portion 22 that fastens the cover 2 and the pipe 200 by threaded fastening is provided, the pipe 200 can be reliably fixed with respect to the internal pressure of the hydrogen gas stored in the storage space 10 of the cylinder 1.

[0054] A seal member 6 is provided between the inner peripheral portion of the lid 2 and the outer peripheral portion of the pipe 200 to block a gap therebetween. This is to prevent a situation in which hydrogen gas stored in the storage space 10 of the cylinder 1 leaks to the outside through the gap between the inner peripheral portion of the lid 2 and the outer peripheral portion of the pipe 200. As an example, the seal member 6 is an O-ring. However, the seal member 6 is not limited to an O-ring, and can be another member as long as it can prevent a situation in which hydrogen gas stored in the storage space 10 of the cylinder 1 leaks to the outside through the gap between the inner peripheral portion of the lid 2 and the outer peripheral portion of the pipe 200.

[0055] A heat insulating member 9 is provided between the lid 2 and the fixing member 4. This is to prevent heat conduction from the lid 2 to the fixing member 4. This is because if the fixing member 4 is cooled to a low temperature by heat conduction, it can be broken due to brittleness. Note that as an example, the heat insulating member 9 is made of ceramic. However, if the length of the lid 2 in the pipe axis direction is long and heat conduction from the lid 2 to the fixing member 4 does not occur, the heat insulating member 9 can be omitted.

[0056] Figure 4 is a modification of the pressure accumulator according to Embodiment 2, and is a cross-sectional view schematically showing the internal structure of the one end side. With respect to Figure 3 The lid 2 of the pressure accumulator 101 shown in FIG. 1 has a threaded fastening portion 22 that fastens the pipe 200 passing through the through-hole 2a by threaded fastening, Figure 4 The pressure accumulator 101A shown in FIG. 2 is configured such that the lid 2 has a welded fixing portion 23 that fixes the pipe 200 passing through the through-hole 2a by welding. The welded fixing portion 23 can be provided to the entire body along the pipe axis direction X, or can be provided to only a part. In this case, since the inner peripheral portion of the lid 2 and the outer peripheral portion of the pipe 200 are completely blocked, the seal member 6 shown in FIG. 1 is not needed. Figure 3

[0057] As described above, since the pressure accumulator 101 and 101A according to Embodiment 2 also have a gap S between the outer peripheral portion of the lid 2 and the inner peripheral portion of the cylinder 1, and at least a part of the gap S is filled with the seal structure portion 3, the gap S functions as a heat insulating layer, and heat conduction from the lid 2 to the cylinder 1 can be suppressed. That is, a situation in which the temperature of the cylinder 1 is lowered by the lid 2 that is cooled to a low temperature by heat conduction from the pipe 200 through which liquid hydrogen at an extremely low temperature passes can be suppressed. Therefore, the pressure accumulator 101 according to Embodiment 2 can inject a liquefied gas at an extremely low temperature from the outside to the inside through the pipe 200, and can vaporize and store the liquefied gas.

[0058] ​The lid 2 is formed of an austenite stainless steel. Therefore, the lid 2 faces the storage space 10 of the cylinder 1 and is always in a state of being exposed to liquid hydrogen at an extremely low temperature, but since it is formed of an austenite stainless steel, it is excellent in brittleness against liquid hydrogen and can ensure strength against an extremely low temperature.

[0059] In addition, the pressure accumulator 101 and 101A according to the present embodiment 2 has a heat insulating member 9 provided between the lid 2 and the fixed member 4. Therefore, heat conduction from the lid 2 to the fixed member 4 can be prevented, and thus, damage to the fixed member 4 due to a decrease in temperature can be prevented.

[0060] Embodiment 3.

[0061] Next, the pressure accumulator 102 according to the present embodiment 3 will be described based on Figure 5 and Figure 6 The pressure accumulator 102 according to the present embodiment 3 will be described. Figure 5 is a sectional view schematically showing the internal structure of the one end side of the pressure accumulator according to the present embodiment 3. Figure 6 is an explanatory view schematically showing the end surface of the outer lid of the pressure accumulator according to the present embodiment 3. Note that the same reference numerals are given to the same constituent elements as those of the pressure accumulator 100 and 101 described in the present embodiments 1 and 2, and the description thereof will be appropriately omitted.

[0062] As shown in Figure 5 , the cylinder 1 of the pressure accumulator 102 according to the present embodiment 3 has a first vent hole 1a for communicating the outside of the cylinder 1 with the gap S and injecting a gas for heat exchange from the outside of the cylinder 1 to the gap S, and a second vent hole 1b for communicating the outside of the cylinder 1 with the gap S and discharging the gas injected into the gap S through the first vent hole 1a to the outside of the cylinder 1. The first vent hole 1a is connected to an injection pipe 300 for injecting the gas. In addition, the second vent hole 1b is connected to a discharge pipe 400 for discharging the gas. The gas is, for example, non-active air, and preferably, dehumidified gas. Note that the gas can be a non-active gas, or can be another gas. The gas is pressurized by a power device such as a compressor and injected into the gap S, circulated in the gap S, and discharged to the outside of the cylinder 1. In the pressure accumulator 102 according to the present embodiment 3, the gas flowing through the gap S makes the gas layer a heat insulating layer, and thus, the effect of suppressing heat conduction from the lid 2 to the cylinder 1 can be improved. In addition, even if a case where hydrogen stored in the storage space 10 of the cylinder 1 leaks to the gap S occurs in the pressure accumulator 102, the leaked hydrogen can be discharged from the second vent hole 1b.

[0063] Additionally, the cover 2 has an inner cover 20 made of austenitic stainless steel and disposed on the storage space side of the cylinder 1, and an outer cover 21 made of low alloy steel and disposed on the fixing component side. A groove 24 is formed on the end face of the outer cover 21, one of the end faces of the inner cover 20 and the other of the outer cover 21, to circulate gas injected from outside the cylinder 1 into the gap S.

[0064] Figure 6 The thicker lines indicate the groove 24. (As shown) Figure 6 As shown, the groove 24 has multiple annular grooves 24a and linear connecting grooves 24b connecting the multiple annular grooves 24a. In the example shown, the multiple annular grooves 24a are composed of three circles surrounding the outer periphery of the through hole 21a. The three circles are formed sequentially at approximately equal intervals, with the larger circle surrounding the outer periphery of the smaller circle. The two ends of the connecting groove 24b lead to the gap S and are formed radially to connect the three circles. Gas injected into the gap S enters from one end of the connecting groove 24b and flows through the annular grooves 24a, and then exits laterally into the gap S from the other end of the connecting groove 24b. In this way, the gas injected into the gap S from the outside of the cylinder 1 circulates in the groove 24, and its gas layer becomes a heat insulation layer, which can improve the effect of suppressing heat conduction from the inner cover 20 to the outer cover 21. It should be noted that when the gas is dry air, even if the gas is cooled during heat exchange, condensation and freezing will not occur in the groove 24 of the cover 21.

[0065] It should be noted that, although omitted in the illustration, a groove 24 can be formed on the end face of the inner cover 20, which is one of the end faces of the inner cover 20 and the outer cover 21 that are opposite to each other. Alternatively, a groove 24 can be formed on the end faces of both the inner cover 20 and the outer cover 21 that are opposite to each other.

[0066] Furthermore, the groove 24 is not limited to the shape shown in the figure. For example, the annular groove 24a is not limited to a circle; it can be rectangular or other shapes. Similarly, the connecting groove 24b is not limited to a straight line; it can be curved, zigzag, or other shapes. Additionally, the groove 24 can be configured as a grid or vortex, or other shapes. In short, the groove 24 can be of any shape as long as it allows the gas injected from the outside of the cylinder 1 into the gap S to circulate on the end face of the inner cover 20 or the end face of the outer cover 21.

[0067] Additionally, it is desirable that the accumulator 102 has a groove 24 on either or both of the end faces of the inner cover 20 and the outer cover 21 that are opposite to each other, but it is not necessary to have the groove 24, and it can be omitted.

[0068] In addition, such as Figure 3and Figure 4 As shown in FIG. 10, the pressure accumulator 102 can be applied to a structure in which the cover 2 is formed of only an austenite stainless steel, for example. However, in this case, the pressure accumulator 102 is omitted Figure 5 and Figure 6 the groove portion 24 shown in FIG. 9.

[0069] Further, the pressure accumulator 102 can be configured to perform control of a condition of the gas injected into the gap S based on a detection value of the temperature detection mechanism 5. The condition of the gas refers to, for example, a flow rate, a flow velocity, an injection time, and the like. Note that the pressure accumulator 102 is not limited to the detection value of the temperature detection mechanism 5, and can use other detection mechanisms to determine the condition of the gas injected into the gap S.

[0070] The pressure accumulators (100, 100A, 101, 101A, 102) have been described above based on the embodiments, but the pressure accumulators (100, 100A, 101, 101A, 102) are not limited to the configurations of the above-described embodiments. The configurations of the above-described pressure accumulators (100, 100A, 101, 101A, 102) are merely examples, and other configuration elements can be included. In short, the pressure accumulators (100, 100A, 101, 101A, 102) include a range of design changes and application variations that are generally made by those skilled in the art, within a range that does not depart from the technical idea thereof.

[0071] Explanation of Reference Numerals

[0072] 1 cylinder, 1a first vent hole, 1b second vent hole, 2 cover, 2a through hole, 3 seal structure portion, 4 fixing member, 5 temperature detection mechanism, 6 seal member, 7, 8, 9 heat insulating member, 10 storage space, 11 internal thread portion, 20 inner cover, 20a through hole, 21 outer cover, 21a through hole, 22 threaded fastening portion, 23 welded fixing portion, 24 groove portion, 24a annular groove portion, 24b connecting groove portion, 100, 100A, 101, 101A, 102 pressure accumulator, 200 pipe, 300 injection pipe, 400 discharge pipe, S gap.

Claims

1. An accumulator, which allows extremely low-temperature liquefied gas to be injected from the outside through piping, thereby vaporizing and storing the liquefied gas. The accumulator has: A metal cylinder with an internal storage space for vaporizing and storing liquefied gas; The cover has a through hole through which the pipe passes, so that the pipe passing through the through hole is fixed, and the opening end of the cylinder is blocked in a state in which a gap communicating with the storage space of the cylinder is provided between the cover and the inner circumferential surface of the cylinder. A sealing structure is disposed between the outer periphery of the cover and the inner periphery of the cylinder, filling at least a portion of the gap; and A fixing component is provided at the open end of the cylinder, and its outer circumferential surface is threaded to the inner circumferential surface of the cylinder, supporting and fixing the cover from the outside.

2. The accumulator as claimed in claim 1, wherein, The cover has a threaded fastening part that secures the pipe passing through the through hole by means of threaded fastening. A sealing component is provided between the inner periphery of the cover and the outer periphery of the pipe to block the gap between them.

3. The accumulator as claimed in claim 1, wherein, The cover has a welded fixing part that secures the pipe passing through the through hole by welding.

4. The accumulator as described in any one of claims 1 to 3, wherein, The cover is made of austenitic stainless steel.

5. The accumulator as claimed in any one of claims 1 to 3, further comprising a heat insulation component disposed between the cover and the fixing component.

6. The accumulator as described in any one of claims 1 to 3, wherein, The cover has: The inner cover, formed of austenitic stainless steel, is disposed on the storage space side of the cylinder; and The outer cover, which is formed of low alloy steel and disposed on the side of the fixing component.

7. The accumulator as claimed in claim 6, wherein, Heat insulation components are respectively provided between the inner cover and the outer cover, and between the outer cover and the piping.

8. The accumulator as claimed in any one of claims 1 to 3, further comprising a temperature detection mechanism for detecting the temperature of the vaporized liquefied gas stored in the storage space of the cylinder, or the temperature of the cover.

9. The accumulator as described in any one of claims 1 to 3, wherein, The cylinder has: A first vent hole, used to communicate the outside of the cylinder with the gap for injecting gas from the outside of the cylinder into the gap; and The second vent is used to connect the outside of the cylinder with the gap so that the gas injected into the gap through the first vent can be discharged to the outside of the cylinder.

10. The accumulator as claimed in claim 9, wherein, The cover has an inner cover made of austenitic stainless steel and disposed on the storage space side of the cylinder, and an outer cover made of low alloy steel and disposed on the fixing component side. A groove is formed on the end face of either or both of the inner cover and the outer cover that are opposite to each other, for the circulation of gas injected into the gap.

11. The accumulator as claimed in claim 10, wherein, The groove has: Multiple annular grooves; and A connecting groove portion, which communicates with the gap and connects to a plurality of the annular groove portions.

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