Low-temperature pressure test device for reducing blasting energy

Abstract

The invention relates to the technical field of gas cylinder pressure testing, in particular to a low-temperature pressure testing device for reducing blasting energy, the low-temperature pressure testing device comprises a gas cylinder, a flexible liner and a filling part, the gas cylinder is provided with a first accommodating space; the flexible inner container and the filling part are both arranged in the first containing space, the flexible inner container is provided with a second containing space, and the filling part is arranged in the second containing space to support the flexible inner container; the flexible inner container and the inner wall of the gas cylinder are at least partially separated, so that a gap for containing a pressurizing medium is formed. The invention provides a low-temperature pressure test device, which solves the technical problem of overlarge blasting energy after medium vaporization after a gas cylinder is filled with a large amount of pressurizing medium, and achieves the technical effect of reducing the blasting energy.

Description

Technical Field

[0001] The present application relates to the technical field of gas cylinder pressure testing, and in particular to a low-temperature pressure testing device for reducing explosion energy. Background Art

[0002] Typical energy media usually have extremely high energy density when stored in cryogenic liquid form, and the storage and transportation equipment of cryogenic liquid energy has also become a rapidly developing direction. As a common means of storage and transportation of such cryogenic liquids, the safety of gas cylinders is also a key factor in ensuring the safe storage and transportation of cryogenic liquids.

[0003] Cryogenic liquids have ultra-low temperature characteristics, and the increase in gas phase space pressure caused by the absorption of heat and vaporization of cryogenic liquids poses a huge challenge to the pressure resistance of gas cylinders under ultra-low temperature conditions. In the actual use of gas cylinders, when the cryogenic liquid absorbs heat and vaporizes to a certain pressure, the safety valve will be opened to release the pressure in time to prevent the pressure from rising and causing the gas cylinder to explode. However, during the design and manufacturing stage of gas cylinders, it is necessary to conduct sufficient low-temperature explosion tests, low-temperature hydrostatic tests, and low-temperature pressure cycle tests on the gas cylinders to fully evaluate the pressure safety of the gas cylinders at various stages of storing cryogenic liquids.

[0004] However, the low-temperature pressure test of gas cylinders is an extremely dangerous test. In the test, low-temperature liquid is added to the inside of the gas cylinder, and the pressure inside the gas cylinder is controlled by compressing the low-temperature liquid. In exploratory low-temperature pressure tests, for example, the gas cylinder will explode instantly after the pressure is increased to a certain level in the low-temperature explosion test, and the gas cylinder will explode instantly during a certain pressure increase process in the low-temperature pressure cycle test. The energy released instantly by the cryogenic liquid due to the sudden explosion of the gas cylinder is much higher than that of the conventional water pressure test or air pressure test.

[0005] Therefore, how to reduce the explosion energy generated by accidental explosion of gas cylinders during low-temperature pressure tests of gas cylinders while ensuring the pressure safety of gas cylinders is the focus of current attention. Summary of the invention

[0006] The present application provides a low-temperature pressure testing device for reducing explosion energy, which solves the technical problem that after a large amount of pressurized medium is filled into a gas cylinder, the explosion energy is too large after the medium is vaporized, and achieves the technical effect of reducing the explosion energy.

[0007] In order to achieve the above objectives, the main technical solutions adopted in this application include:

[0008] An embodiment of the present application provides a low-temperature pressure testing device for reducing explosion energy, comprising a gas cylinder, a flexible liner and a filling portion, wherein the gas cylinder has a first accommodating space; the flexible liner and the filling portion are both arranged in the first accommodating space, the flexible liner has a second accommodating space, and the filling portion is arranged in the second accommodating space to support the flexible liner; wherein the flexible liner is at least partially spaced apart from the inner wall of the gas cylinder to form a gap for accommodating a medium.

[0009] The pressure test device proposed in the embodiment of the present application is that the gas cylinder has a first accommodating space, a flexible liner and a filling part are added in the first accommodating space, the filling part is arranged in the second accommodating space of the flexible liner and supports the flexible liner, the volume of the flexible liner after being supported by the filling part is smaller than the volume of the first accommodating space, the outer wall of the flexible liner and the inner wall of the gas cylinder are at least partially separated to form a gap, and the medium is filled in the gap for pressure testing. The arrangement of the flexible liner and the filling part reduces the volume of the pressurized medium in the gas cylinder for pressure testing, solves the problem of large blasting energy generated by the explosion of the gas cylinder after the medium is vaporized due to a large amount of pressurized medium being filled in the gas cylinder, and reduces the blasting energy. In addition, the filling part is arranged in the flexible liner, and in the first accommodating space, the filling part and the flexible liner are an integral structure, which also reduces the kinetic energy transmitted by the instantaneous explosion.

[0010] Optionally, the pressure test device further comprises a positioning part, which is arranged between the flexible liner and the inner wall of the gas cylinder to separate the flexible liner from the inner wall of the gas cylinder. The positioning part is arranged between the flexible liner and the inner wall of the gas cylinder to separate the flexible liner from the inner wall of the gas cylinder, and a gap is formed between the flexible liner and the inner wall of the gas cylinder, and the gap is filled with the medium for pressure test. The volume of the gap is smaller than the volume in the gas cylinder, that is, the volume of the filling medium is reduced, thereby reducing the energy generated by the filling medium when the gas cylinder explodes.

[0011] Optionally, the gas cylinder has a rotation axis, and along the length direction of the rotation axis, the gas cylinder includes a first straight section, a first arc section and a second arc section, and the first arc section and the second arc section are connected to two ends of the first straight section; along the length direction of the rotation axis, the flexible liner includes a second straight section, a third arc section and a fourth arc section, and the third arc section and the fourth arc section are connected to two ends of the second straight section; the positioning portion includes a plurality of first positioning portions, and along the circumference of the gas cylinder, the plurality of first positioning portions are spaced between the first straight section and the second straight section to at least separate the first straight section and the second straight section. The second straight section of the flexible liner corresponds to the first straight section of the gas cylinder, the third arc section of the flexible liner corresponds to the first arc section of the gas cylinder, the fourth arc section of the flexible liner corresponds to the second arc section of the gas cylinder, and a plurality of first positioning parts spaced apart along the circumference of the gas cylinder are provided between the second straight section of the flexible liner and the first straight section of the gas cylinder, and the first positioning parts space the first straight section and the second straight section apart to form a gap filled with a medium. The plurality of spaced apart first positioning parts keep the gap between the first straight section and the second straight section uniform and stable, so that the temperature and pressure distribution at each location in the gap is uniform.

[0012] Optionally, the first positioning portion has a first through hole, and the first through hole penetrates the first positioning portion along the circumference of the gas cylinder. The first positioning portion has the first through hole penetrating the first positioning portion, so that the medium filled in the gap can fully flow.

[0013] Optionally, the first through holes are multiple and spaced apart along the rotation axis. The first positioning portion has multiple first through holes, so that the first positioning portion obstructs the flow of the medium in the gap as little as possible, ensuring that the medium in each part of the gap can flow fully and the medium in each part of the gap is evenly distributed.

[0014] Optionally, the positioning portion further includes a plurality of second positioning portions and a plurality of third positioning portions; along the circumference of the gas cylinder, a plurality of second positioning portions are spaced between the first arc segment and the third arc segment to at least separate the first arc segment from the third arc segment, and a plurality of third positioning portions are spaced between the second arc segment and the fourth arc segment to separate the second arc segment from the fourth arc segment. A plurality of second positioning portions spaced apart along the circumference of the gas cylinder are provided between the first arc segment and the third arc segment, the second positioning portions separate the first arc segment from the third arc segment, and a gap is formed between the first arc segment and the third arc segment; a plurality of third positioning portions spaced apart along the circumference of the gas cylinder are provided between the second arc segment and the fourth arc segment, the third positioning portions separate the second arc segment from the fourth arc segment, and a gap is formed between the second arc segment and the fourth arc segment. The arrangement of the plurality of first positioning portions, the plurality of second positioning portions and the plurality of third positioning portions allows the gap between the inner wall of the gas cylinder and the outer wall of the flexible liner to be evenly arranged, thereby allowing the temperature and pressure distribution at each location in the gap to be even.

[0015] Optionally, the second positioning portion has a second through hole, and the second through hole penetrates the second positioning portion along the circumference of the gas cylinder; the third positioning portion has a third through hole, and the third through hole penetrates the third positioning portion along the circumference of the gas cylinder. The second positioning portion has the second through hole, so that the medium in the gap between the first arc segment and the third arc segment can flow fully; the third positioning portion has the third through hole, so that the medium in the gap between the second arc segment and the fourth arc segment can flow fully.

[0016] Optionally, the gas cylinder has an opening connected to the first accommodation space, and the pressure testing device further includes a connecting joint at least partially located in the opening; the connecting joint has a first channel and a second channel, the first channel is connected to the gap, and the second channel is connected to the second accommodation space. The medium is filled into the gap through the first channel, and the filling part is filled into the second accommodation space of the flexible liner through the second channel, and the filling part is used to support the flexible liner.

[0017] Optionally, there is one second channel and a plurality of first channels, and the plurality of first channels are arranged at intervals along the circumference of the second channel. The first channels are arranged at intervals around the circumference of the second channel, so that the medium filled in the gap is uniform everywhere.

[0018] Optionally, the volume of the flexible liner is smaller than the volume of the accommodation space, and the ratio of the volume of the flexible liner to the volume of the first accommodation space is a, satisfying: a≥80%. The volume of the flexible liner is greater than or equal to 80% of the volume of the first accommodation space, which fully reduces the volume of the medium in the gap, thereby achieving the purpose of reducing the explosion energy of the gas cylinder. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 This is a schematic diagram of the structure of the pressure test device for this application;

[0021] Figure 2 A schematic cross-sectional view of the pressure test device of this application;

[0022] Figure 3 This is a schematic diagram of the structure of the gas cylinder opening of the pressure testing device in this application.

[0023] [Description of Reference Numerals]

[0024] 1: gas cylinder; 10: gap; 11: first straight section; 12: first arc section; 13: second arc section; 14: opening; 15: rotation axis; 2: flexible liner; 21: second straight section; 22: third arc section; 23: fourth arc section; 3: filling part; 4: positioning part; 41: first positioning part; 410: first through hole; 42: second positioning part; 420: second through hole; 43: third positioning part; 430: third through hole; 5: connecting joint; 51: first channel; 52: second channel. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0026] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as those commonly understood by technicians in the technical field of this application; the terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned drawings and any variations thereof are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship.

[0027] Reference to "embodiments" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in this application may be combined with other embodiments.

[0028] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "attached" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0029] The term "and / or" in this application is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this application generally indicates that the associated objects before and after are in an "or" relationship.

[0030] The term "multiple" as used in this application refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple sheets" refers to more than two sheets (including two sheets).

[0031] Typical energy media such as hydrogen, oxygen, and methane usually have extremely high energy density when stored in cryogenic liquid form. Storage and transportation equipment corresponding to cryogenic liquid energy such as liquid hydrogen, liquid oxygen, and liquefied natural gas has also become a rapidly developing direction. As a common means of storage and transportation of such cryogenic liquids, the safety of gas cylinders is also a key factor in ensuring the safe storage and transportation of cryogenic liquids.

[0032] Cryogenic liquids have ultra-low temperature characteristics (liquid hydrogen -253°C, liquid oxygen -183°C, liquefied natural gas -162°C), and the increase in gas phase space pressure caused by the absorption of heat and vaporization of cryogenic liquids poses a huge challenge to the pressure resistance of gas cylinders under ultra-low temperature conditions. In the actual use of gas cylinders, when the cryogenic liquid absorbs heat and vaporizes to a certain pressure, the safety valve will open to release the pressure in time to prevent the pressure from increasing and causing the gas cylinder to explode. However, during the design and manufacturing stage of the gas cylinder, it is necessary to carry out sufficient low-temperature explosion tests, hydrostatic tests, pressure cycle tests and other pressure tests on the gas cylinders to fully evaluate the pressure safety of the gas cylinders at various stages of storing cryogenic liquids.

[0033] However, the low-temperature pressure test of gas cylinders is an extremely dangerous test. During the test, cryogenic liquids such as liquid hydrogen and liquid nitrogen are added to the inside of the gas cylinder, and the pressure inside the gas cylinder is controlled by compressing the cryogenic liquid. In exploratory low-temperature pressure tests, for example, the gas cylinder will explode instantly after being pressurized to a certain pressure in a low-temperature explosion test, and the gas cylinder will explode instantly during a certain pressurization process in a low-temperature pressure cycle test. The energy released instantly by the cryogenic liquid due to the sudden explosion of the gas cylinder is much higher than that of conventional water pressure tests or gas pressure tests (for example, 1 unit of liquid nitrogen can expand to 696 units of nitrogen, and 1 unit of liquid hydrogen can expand to 788 units of hydrogen); the inventor team evaluated: for a 1000L gas cylinder, using liquid nitrogen as a low-temperature increase medium, the explosion energy at a pressure of 3.2MPa will exceed 30MJ, which is equivalent to the explosion of more than 7kg of TNT.

[0034] Simply reducing the amount of liquid medium injected into the gas cylinder cannot effectively test the pressure safety of the gas cylinder. Therefore, how to reduce the explosion energy generated by accidental explosion of the gas cylinder during the low-temperature pressure test of the gas cylinder while ensuring the pressure safety of the gas cylinder is the focus of current attention.

[0035] In the related art, some solutions propose to add low-temperature resistant fillers that are compatible with the hydraulic oil and the test medium into the gas cylinder, thereby reducing the internal volume of the gas cylinder to reduce the amount of pressurized medium added. This method can indeed reduce the energy released when the gas cylinder explodes at low temperature, but if the filler is in direct contact with the pressurized medium, at the moment of the low-temperature explosion of the gas cylinder, a huge initial kinetic energy will be provided to the filler, causing the filler to splash rapidly with the explosion of the gas cylinder, resulting in more serious consequences; and the molding state of the filler inside the gas cylinder is also difficult to control, and uneven filling will cause local stress concentration in the gas cylinder and uneven distribution of internal pressure. In addition, the existing low-temperature pressure tests of gas cylinders are all to cool the outside of the gas cylinder, and the low-temperature pressure test is carried out inside by means of high-pressure gas. In the test using low-temperature liquid direct pressurization, the explosion energy will be even greater, and the related technical solutions are difficult to provide effective technical instructions for such tests.

[0036] In the low-temperature pressure test of gas cylinders, the energy generated by the explosion of the gas cylinder is huge. In order to reduce the energy generated by the explosion of the gas cylinder, it is considered to add fillers such as hydraulic oil inside the gas cylinder to reduce the energy released by the explosion of the gas cylinder. However, the filler is in direct contact with the medium in the gas cylinder. At the moment of the explosion of the gas cylinder, the filler is also given huge initial kinetic energy, which makes the filler splash rapidly with the explosion of the gas cylinder, causing serious consequences. Therefore, it is necessary to develop a low-temperature pressure test device for reducing the explosion energy, which can reduce the medium capacity in the gas cylinder and reduce the explosion energy of the gas cylinder while avoiding the splash of the filler and causing serious consequences. Among them, the low-temperature pressure test includes a short-term low-temperature explosion test, a long-term low-temperature hydrostatic test or a low-temperature pressure cycle test.

[0037] refer to Figure 1 and Figure 2 The embodiment of the present application provides a low-temperature pressure test device for reducing explosion energy, including a gas cylinder 1, a flexible liner 2 and a filling part 3. The gas cylinder 1 has a first accommodation space; the flexible liner 2 and the filling part 3 are both arranged in the first accommodation space, the flexible liner 2 has a second accommodation space, and the filling part 3 is arranged in the second accommodation space to support the flexible liner 2; wherein the flexible liner 2 is at least partially spaced apart from the inner wall of the gas cylinder 1 to form a gap 10 for accommodating a medium. The second accommodation space in the flexible liner 2 is used to accommodate the filling part 3, and the gap 10 between the outer wall of the flexible liner 2 and the inner wall of the gas cylinder 1 is used to accommodate a low-temperature pressurized medium.

[0038] Specifically, the flexible liner 2 is a flexible material, and the flexible liner 2 can maintain flexibility under normal temperature and low temperature conditions, and can be folded so as to enter the first accommodation space through the opening 41 of the gas cylinder 1. The material of the flexible liner 2 can be at least one of polyimide, polytetrafluoroethylene, polystyrene, etc. or polyetheretherketone, etc. The filling part 3 is arranged inside the flexible liner 2, and is composed of a soft material that can be cured under specific conditions; the soft material has the ability to withstand low temperatures without cracking at low temperature medium temperatures, such as the filling part 3 can be an expandable foaming material such as polystyrene foam, polyurethane foam, polyimide foam; it can also be an injectable composite material such as an acrylic composite material, a polyurethane composite material, as long as the liquid or fluid can be injected into the flexible liner 2 and foamed and cured under certain conditions. After curing in the flexible liner 2, the filling part 3 forms a rigid supporting filling structure for maintaining the shape of the flexible liner 2, and providing the required structural rigidity for the flexible liner 2 when the medium in the gap 10 is low-temperature pressurized. The pressure testing device is suitable for low-temperature pressure testing of gas cylinders pressurized with low-temperature liquids. By arranging a flexible liner 2 and a filling part 3 inside the gas cylinder 1, the volume of the low-temperature medium pressurization space is reduced. The soft material used in the filling part 3 has an energy-absorbing effect, which can further effectively reduce the explosion energy generated when the gas cylinder 1 explodes accidentally.

[0039] The gas cylinder 1 can be a double-layer insulated gas cylinder, a fiber-wound gas cylinder, a steel structure reinforced gas cylinder or a fully composite lightweight gas cylinder. The medium filled in the gap 10 can be a single cryogenic liquid such as liquid nitrogen, liquid helium, liquid hydrogen, or a multiphase cryogenic liquid or a cryogenic gas-liquid mixture such as liquid nitrogen, liquid helium, liquid hydrogen, hydrogen, helium, nitrogen, etc.

[0040] The low-temperature pressure test device proposed in the embodiment of the present application, the gas cylinder 1 has a first accommodation space, a flexible liner 2 and a filling part 3 are added in the first accommodation space, the filling part 3 is arranged in the second accommodation space of the flexible liner 2, the volume of the flexible liner 2 after being supported by the filling part 3 is smaller than the volume of the first accommodation space, the outer wall of the flexible liner 2 and the inner wall of the gas cylinder 1 are at least partially separated to form a gap 10, and the medium is filled in the gap 10 for pressure testing. The arrangement of the flexible liner 2 and the filling part 3 reduces the volume of the filling medium used for pressure testing in the gas cylinder 1, solves the problem of large explosion energy generated by the explosion of the gas cylinder after the medium is vaporized due to the filling of a large amount of pressurized medium in the gas cylinder, and reduces the explosion energy. In addition, the filling part 3 is arranged in the flexible liner 2. In the first accommodation space, the filling part 3 and the flexible liner 2 are an integral structure, which also reduces the kinetic energy transmitted by the instantaneous explosion. That is to say, by providing the flexible liner 2 and the filling part 3, the uniformity of the pressure distribution inside the gas cylinder 1 during the low-temperature pressure test can be ensured, and the flexible liner 2 and the filling part 3 can be used as a uniform whole, which can reduce the kinetic energy transmitted by the instantaneous explosion of the gas cylinder 1.

[0041] Optionally, the pressure test device further includes a positioning portion 4, which is disposed between the flexible liner 2 and the inner wall of the gas cylinder 1 to separate the flexible liner 2 from the inner wall of the gas cylinder 1. The positioning portion 4 is disposed between the flexible liner 2 and the inner wall of the gas cylinder 1, and the positioning portion 4 can be attached to the outer wall of the flexible liner 2 by gluing, welding, etc. to separate the flexible liner 2 from the inner wall of the gas cylinder 1, and a gap 10 is formed between the flexible liner 2 and the inner wall of the gas cylinder 1, and the gap 10 is used as a space for filling the pressure test medium. The volume of the gap 10 is smaller than the volume in the gas cylinder 1, that is, the volume of the filling medium is reduced, thereby reducing the energy generated by the medium filled in the gap 10 of the gas cylinder 1 when the gas cylinder 1 explodes. Among them, the positioning part 4 can be a non-metallic material such as polytetrafluoroethylene, polyethylene, polypropylene, polymethyl methacrylate or epoxy resin; it can also be a metal material such as stainless steel, aluminum alloy, etc., as long as it can be supported between the outer wall of the flexible liner 2 and the inner wall of the gas cylinder 1 so that there is a gap 10 between the outer wall of the flexible liner 2 and the inner wall of the gas cylinder 1 to accommodate the medium.

[0042] Optionally, refer to Figure 1The gas cylinder 1 has a rotation axis 15. Along the length direction of the rotation axis 15, the gas cylinder 1 includes a first straight section 11, a first arc section 12 and a second arc section 13, and the first arc section 12 and the second arc section 13 are connected to both ends of the first straight section 11; along the length direction of the rotation axis 15, the flexible liner 2 includes a second straight section 21, a third arc section 22 and a fourth arc section 23, and the third arc section 22 and the fourth arc section 23 are connected to both ends of the second straight section 21; the positioning portion 4 includes a plurality of first positioning portions 41, and along the circumference of the gas cylinder 1, the plurality of first positioning portions 41 are spaced apart between the first straight section 11 and the second straight section 21 to at least separate the first straight section 11 from the second straight section 21. The second straight section 21 of the flexible liner 2 corresponds to the first straight section 11 of the gas cylinder 1, the third arc section 22 of the flexible liner 2 corresponds to the first arc section 12 of the gas cylinder 1, and the fourth arc section 23 of the flexible liner 2 corresponds to the second arc section 13 of the gas cylinder 1. A plurality of first positioning portions 41 spaced apart along the circumference of the gas cylinder 1 are provided between the second straight section 21 of the flexible liner 2 and the first straight section 11 of the gas cylinder 1. The first positioning portions 41 space the first straight section 11 and the second straight section 21 apart to form a gap 10 filled with a medium. The plurality of spaced apart first positioning portions 41 allow the second straight section 21 of the flexible liner 2 to be located at the central position in the gas cylinder 1, thereby maintaining the gap 10 between the first straight section 11 and the second straight section 21 uniform and stable, thereby achieving uniform temperature and pressure distribution at various locations in the gap 10.

[0043] Optionally, the first positioning portion 41 has a first through hole 410, and the first through hole 410 passes through the first positioning portion 41 along the circumference of the gas cylinder 1. The first positioning portion 41 has a first through hole 410 passing through the first positioning portion 41, that is, along the circumference of the gas cylinder 1, the first through hole 410 of each first positioning portion 41 can be connected, so that the medium filled in the gap 10 can be fully circulated. In an optional embodiment, the first through holes 410 of each first positioning portion 41 are correspondingly arranged in the circumference of the gas cylinder 1, that is, the center lines of the correspondingly arranged first through holes 410 are on the same plane, and the plane is perpendicular to the rotation axis 15 of the gas cylinder 1.

[0044] Optionally, there are multiple first through holes 410 and they are spaced apart along the axis of rotation 15. Specifically, each first positioning portion 41 extends along the length direction of the axis of rotation 15 of the gas cylinder 1 and is supported between the flexible liner 2 and the inner wall of the gas cylinder 1. Optionally, the length of the first positioning portion 41 is close to the length of the second straight section 21. Along the length direction of the axis of rotation 15, the first positioning portion 41 has multiple first through holes 410 spaced apart, so that the first positioning portion 41 obstructs the flow of the medium in the gap 10 as little as possible, ensuring that the medium in various locations in the gap 10 can flow fully and the medium in various locations in the gap 10 is evenly distributed. In an optional embodiment, multiple first positioning portions 41 are spaced apart along the circumference of the gas cylinder 1, and the first through holes 410 of the multiple first positioning portions 41 are arranged one by one along multiple planes perpendicular to the axis of rotation 15, so that the low-temperature medium in various locations in the gap 10 can flow fully. Specifically, there are four first positioning portions 41 which are spaced apart along the circumference of the gas cylinder 1 ; each first positioning portion 41 has three first through holes 410 spaced apart along the length direction of the rotation axis 15 .

[0045] Optionally, the positioning portion 4 also includes a plurality of second positioning portions 42 and a plurality of third positioning portions 43; along the circumference of the gas cylinder 1, the plurality of second positioning portions 42 are spaced apart between the first arc segment 12 and the third arc segment 22 to at least separate the first arc segment 12 from the third arc segment 22, and the plurality of third positioning portions 43 are spaced apart between the second arc segment 13 and the fourth arc segment 23 to separate the second arc segment 13 from the fourth arc segment 23. A plurality of second positioning portions 42 spaced apart along the circumference of the gas cylinder 1 are provided between the first arc segment 12 and the third arc segment 22, and the second positioning portions 42 space the first arc segment 12 and the third arc segment 22, and a gap 10 is formed between the first arc segment 12 and the third arc segment 22; a plurality of third positioning portions 43 spaced apart along the circumference of the gas cylinder 1 are provided between the second arc segment 13 and the fourth arc segment 23, and the third positioning portions 43 space the second arc segment 13 and the fourth arc segment 23, and a gap 10 is formed between the second arc segment 13 and the fourth arc segment 23. The provision of the plurality of first positioning portions 41, the plurality of second positioning portions 42, and the plurality of third positioning portions 43 enables the flexible liner 2 to be located at the central position in the gas cylinder 1, so that the gap 10 between the inner wall of the gas cylinder 1 and the outer wall of the flexible liner 2 is evenly provided, thereby achieving uniform temperature and pressure distribution at various locations in the gap 10.

[0046] Specifically, the flexible liner 2 can maintain flexibility under normal and low temperature conditions, and can be folded so as to be inserted into the gas cylinder 1 through the mouth of the gas cylinder 1. After the flexible liner 2 is inflated, the positioning portion 4 contacts the inner wall of the gas cylinder 1, and a gap 10 is formed in the middle area between the inner wall of the gas cylinder 1 and the outer wall of the flexible liner 2 for filling the low-temperature medium. The flexible liner 2 is separated from the inner wall of the gas cylinder 1 by the positioning portion 4, so that the flexible liner 2 is supported by the positioning portion 4 and maintained in the central area inside the gas cylinder 1 after uniform expansion, that is, the gap 10 between the outer wall of the flexible liner 2 and the inner wall of the gas cylinder 1 is uniform everywhere.

[0047] Optionally, the second positioning portion 42 has a second through hole 420, and the second through hole 420 penetrates the second positioning portion 42 along the circumference of the gas cylinder 1; the third positioning portion 43 has a third through hole 430, and the third through hole 430 penetrates the third positioning portion 43 along the circumference of the gas cylinder 1. The second positioning portion 42 has the second through hole 420, so that the medium in each part of the gap 10 between the first arc segment 12 and the third arc segment 22 can flow fully; the third positioning portion 43 has the third through hole 430, so that the medium in each part of the gap 10 between the second arc segment 13 and the fourth arc segment 23 can flow fully.

[0048] In an optional embodiment, the length direction of the first positioning portion 41 is parallel to the rotation axis 15 of the gas cylinder 1, and is evenly arranged and installed in the circumferential direction of the flexible liner 2. The thickness of the first positioning portion 41, the second positioning portion 42, and the third positioning portion 43 are the same, ensuring that the gap 10 between the outer wall of the flexible liner 2 and the inner wall of the gas cylinder 1 is uniform everywhere, thereby making the pressure distribution uniform everywhere in the gap 10 to prevent stress concentration. The first positioning portion 41, the second positioning portion 42, and the third positioning portion 43 are also the same in width, so that the medium in the gap 10 between the outer wall of the flexible liner 2 and the inner wall of the gas cylinder 1 is uniform and fully circulated everywhere.

[0049] In some optional embodiments, the first positioning portion 41 is further provided with a through hole penetrating the first positioning portion 41 in the direction of the rotation axis 15 , thereby allowing the low-temperature medium in various locations in the gap 10 to flow more fully.

[0050] Optionally, refer to Figure 3 The gas cylinder 1 has an opening 14 connected to the first accommodation space, and the pressure test device also includes a connection joint 5 at least partially located in the opening 14; the connection joint 5 has a first channel 51 and a second channel 52, the first channel 51 is connected to the gap 10, and the second channel 52 is connected to the second accommodation space. The medium is filled into the gap 10 through the first channel 51, and the soft material or foaming material is filled into the second accommodation space of the flexible liner 2 through the second channel 52 to form a filling part 3, and the filling part 3 is used to support the flexible liner 2.

[0051] Optionally, there is one second channel 52 and multiple first channels 51, and the multiple first channels 51 are arranged at intervals along the circumference of the second channel 52. The first channels 51 are arranged at intervals around the circumference of the second channel 52, so that the medium filled in the gap 10 is uniform everywhere.

[0052] In an optional embodiment, the connecting joint 5 is a valve seat, and the valve seat is fixed to the opening 14 of the flexible liner 2 by gluing. A second channel 52 is provided in the center of the valve seat for inflating the flexible liner 2 and filling the filling part 3; a first channel 51 is provided on the outside of the second channel 52 and is evenly distributed along the second channel 52, which is connected to the low-temperature medium pressurization space and is used for filling and pressure control of the low-temperature medium in the low-temperature pressure test of the gas cylinder 1. In other words, the soft material enters the flexible liner 2 through the second channel 52 at the valve seat of the flexible liner 2, and forms a rigid filling part 3 after solidification inside the flexible liner 2, which is used to maintain the shape of the flexible liner 2 and provide the required structural rigidity when the low-temperature medium is pressurized in the gap outside the flexible liner 2. The valve seat fixed to the flexible liner 2 is connected to the opening 14 of the gas cylinder 1, avoiding the secondary dangerous consequences caused by the flexible liner 2 or the filling part 3 flying away.

[0053] Optionally, the volume of the flexible liner 2 is smaller than the volume of the accommodation space, and the ratio of the volume of the flexible liner 2 to the volume of the first accommodation space is a, satisfying: a≥80%. The volume of the flexible liner 2 is greater than or equal to 80% of the volume of the first accommodation space, which fully reduces the volume of the medium in the gap 10, thereby achieving the purpose of reducing the explosion energy of the gas cylinder 1.

[0054] The pressure testing device proposed in the present application has a flexible inner liner 2 and a surface positioning portion 4 which can be easily folded into the interior of the gas cylinder 1, and a valve seat is provided at one end of the flexible inner liner 2 to facilitate connection with the opening 14 of the gas cylinder 1; after the valve seat is fixed, the filling portion 3 and the gap 10 are independent of each other, and the overall installation of the device is efficient and convenient.

[0055] The pressure testing device of the present application includes a flexible inner liner 2, a filling part 3 and a gap 10 between the flexible inner liner 2 and the gas cylinder 1, and an end valve seat is provided at one end of the flexible inner liner 2; the flexible inner liner 2 is inserted into the gas cylinder 1 in a folded manner, and the valve seat at the end of the flexible inner liner 2 is fixedly connected to the opening 14 of the gas cylinder 1 using a connecting interface; the internal space of the flexible inner liner 2 is the filling part 3, and the external space of the flexible inner liner 2 is the gap 10, that is, the low-temperature medium pressurization space.

[0056] Flexible liner 2 and its positioning part 4 structure reference Figure 2 The shape of the flexible liner 2 is similar to that of the gas cylinder 1, and a flexible liner 2 positioning portion 4 is provided on the outer wall of the flexible liner 2. After the flexible liner 2 is inflated, the positioning portion 4 contacts the inner wall of the gas cylinder 1 to achieve the positioning of the flexible liner 2 inside the gas cylinder 1.

[0057] Reference for the valve seat structure at the end of the flexible liner 2 Figure 3 , the valve seat includes a connection interface connected to the opening 14 of the gas cylinder 1, a first channel 51 for filling the medium, and a second channel 52 for filling the filling part 3 in the flexible inner liner 2. That is to say, the first channel 51 connects the gap between the outer wall of the flexible inner liner 2 and the inner wall of the gas cylinder 1, and the second channel 52 connects the second accommodating chamber of the flexible inner liner 2. After the flexible inner liner 2 is inserted into the gas cylinder 1, the flexible inner liner 2 is inflated through the second channel 52. After the flexible inner liner 2 expands, a soft material or foaming material that can be cured under specific conditions is added to the flexible inner liner 2 through the second channel 52, and the soft material or foaming material is fully cured to form the filling part 3; during the low-temperature pressure test of the gas cylinder 1, the first channel 51 is connected to the external low-temperature medium filling pipeline, and after the first channel 51 is completely filled with the low-temperature medium, the pressurization effect of the gas cylinder 1 is achieved by compressing the low-temperature medium, and the low-temperature pressure test of the gas cylinder 1 is started.

[0058] The following is a specific application of a pressure test device for reducing explosion energy in a development test phase of a vehicle-mounted liquefied natural gas (LNG) cylinder 1 according to an embodiment.

[0059] Commercial heavy trucks are equipped with on-board LNG cylinders with a capacity of 1000L. The on-board LNG cylinders adopt a double-layer stainless steel cylinder structure, in which the inner stainless steel cylinder is the storage carrier of LNG, and the middle of the inner and outer layers is a high vacuum insulation interlayer to ensure the insulation storage of LNG, and the outer shell is used to ensure the integrity of the high vacuum insulation layer. The effective volume of the inner stainless steel cylinder (hereinafter referred to as cylinder 1) is 1000L, the outer diameter of cylinder 1 is 850mm, the length of the first straight section 11 of cylinder 1 is 1500mm, the wall thickness is 6mm, and the design nominal working pressure is 1.6MPa. In order to verify the pressure resistance safety of cylinder 1 storing ultra-low temperature LNG medium, it is necessary to carry out a low-temperature pressure test on cylinder 1.

[0060] In the low-temperature pressure test of the gas cylinder, the pressure test device for reducing the explosion energy proposed in this application is first assembled. Among them, the flexible liner 2 is made of polyimide material, and the polyimide liner is formed by hot pressing technology, and its shape is similar to that of the gas cylinder 1; the outer diameter of the flexible liner 2 is 800mm, the second straight section 21 of the flexible liner 2 is 1500mm long, the wall thickness is 3mm, and the effective volume is 890L. After the flexible liner 2 is installed, the volume of the space inside the gas cylinder 1 for low-temperature medium pressurization is 110L.

[0061] A positioning part 4 is installed on the outer wall of the flexible liner 2 for positioning the flexible liner 2. The positioning part 4 is made of an epoxy resin plate and is fixed to the outer wall of the flexible liner 2 by gluing. The first positioning part 41 at the second straight section 21 of the flexible liner 2 adopts a rectangular parallelepiped structure, and its length along the rotation axis 15 of the gas cylinder is 1300mm, the width along the circumferential direction is 30mm, and the thickness along the radial direction is 50mm. The first positioning part 41 at the second straight section 21 is provided with three evenly arranged first through holes 410 for the circulation of low-temperature medium. The length of a single first through hole 410 along the rotation axis 15 of the gas cylinder is 320mm, the height along the radial direction is 30mm, and it is completely through along the circumferential direction. The second positioning portion 42 of the third arc segment 22 of the flexible liner 2 adopts a fan ring structure consistent with the curve shape of the first arc segment 12, and the third positioning portion 43 at the fourth arc segment 23 adopts a fan ring structure consistent with the curve shape of the second arc segment 13. The arc length of the second positioning portion 42 and the third positioning portion 43 is 520mm, the circumferential width is 30mm, and the radial thickness is 50mm. The second positioning portion 42 at the third arc segment 22 has a second through hole 420, and the third positioning portion 43 at the fourth arc segment 23 has a third through hole 430. The second through hole 420 and the third through hole 430 are used for the circulation of low-temperature media. The arc length of the second through hole 420 and the third through hole 430 is 400mm, the radial height is 30mm, and the circumferential direction is completely through. The first positioning portion 41, the second positioning portion 42 and the third positioning portion 43 are evenly spaced in four directions of 0 degrees, 90 degrees, 180 degrees, and 270 degrees along the circumferential direction of the gas cylinder 1.

[0062] After the flexible liner 2 is formed and the positioning part 4 is installed, one end of the flexible liner 2 is bonded and fixed to the valve seat using acrylic adhesive. The other end of the flexible liner 2 is inserted into the gas cylinder 1. After it is fully inserted, the valve seat is threadedly connected to the opening 14 of the gas cylinder 1. Inflate the flexible liner 2 from the second channel 52 in the center of the valve seat to fully expand the flexible liner 2, and the positioning part 4 on the flexible liner 2 is in full contact with the inner wall surface of the gas cylinder 1. Then, a 40°C polyurethane foaming mixture is introduced from the second channel 52 in the center of the valve seat to make it spontaneously and evenly foam inside the flexible liner 2 to form a dense, high-rigidity polyurethane rigid foam as the filling part 3.

[0063] The flexible liner 2 and the filling part 3 formed of polyurethane rigid foam are located in the gas cylinder 1. In the low-temperature pressure test of the gas cylinder, liquid nitrogen is used as the pressurizing medium, and liquid nitrogen is added from multiple first channels 51 evenly distributed on the valve seat in a two-way filling form, that is, during the liquid nitrogen filling process, the gas in the space or the low-temperature nitrogen that absorbs heat and evaporates is removed in real time until the low-temperature medium pressurization space is completely filled with liquid nitrogen, and the liquid nitrogen explosion test is started until the gas cylinder 1 is completely failed and destroyed.

[0064] The above implementation includes the design and installation steps of the pressure test device for reducing the explosion energy, as well as the low-temperature pressure test process of the supporting gas cylinder. Considering that the explosion energy of the gas cylinder 1 is difficult to measure through the test, this embodiment uses the boiling liquid expansion steam explosion model to estimate the energy change of the gas cylinder 1 under liquid nitrogen explosion before and after the test using the pressure test device of this application:

[0065] The test pressure (minimum bursting pressure) of gas cylinder 1 proposed in GB / T34510 is not less than 2 times the nominal working pressure, that is, when the nominal working pressure of gas cylinder 1 is 1.6MPa, its theoretical bursting pressure is about 3.2MPa. At the moment of gas cylinder 1 destruction, the energy released makes the liquid nitrogen in an overheated state. At this time, the energy released by the overheated liquid nitrogen when gas cylinder 1 explodes is calculated according to the following formula:

[0066] E=[(H1-H2)-(S1-S2)T1]W

[0067] Wherein, E is the explosion energy of superheated liquid nitrogen, in kJ; H1 is the enthalpy of saturated liquid nitrogen at the time of explosion, in kJ / kg; H2 is the enthalpy of saturated liquid nitrogen at atmospheric pressure, in kJ / kg; S1 is the entropy of saturated liquid nitrogen at the time of explosion, in kJ / (kg·K); S2 is the entropy of saturated liquid nitrogen at atmospheric pressure, in kJ / (kg·K); T1 is the boiling point of liquid nitrogen at atmospheric pressure, in K; W is the mass of added liquid nitrogen, in kg.

[0068] ① For the gas cylinder 1 that does not use the pressure test device of this application, the effective volume is 1000L, when it is exploded at 3.2MPa 77K liquid nitrogen low temperature:

[0069] The mass of liquid nitrogen: W = ρ liq ×V liq =870 kg / m 3 ×1 m 3 =870 kg

[0070] Enthalpy difference: H1-H2=6.68-(-120.17)=126.85 kJ / kg

[0071] The entropy difference is multiplied by the temperature:

[0072] (S1-S2)×T1=(4.03-2.86)×77.4=1.17×77.4=90.51 kJ / kg

[0073] Combined calculation: E = (126.85-90.51) × 870 = 31615.8 kJ

[0074] The average blast energy released by the explosion of 1kg of TNT is usually defined as 4500kJ / kg. At this time, the blast energy of gas cylinder 1 is equal to the blast energy of 7.0kg of TNT.

[0075] ② For the gas cylinder 1 using the pressure test device of this application, the effective volume is 110L, when it is exploded at 3.2MPa 77K liquid nitrogen low temperature:

[0076] The mass of liquid nitrogen: W = ρ liq ×V liq =870kg / m3×0.11m3=95.7kg

[0077] Enthalpy difference: H1-H2=6.68-(-120.17)=126.85 kJ / kg

[0078] The entropy difference is multiplied by the temperature:

[0079] (S1-S2)×T1=(4.03-2.86)×77.4=1.17×77.4=90.51kJ / kg

[0080] Combined calculation: E = (126.85-90.51) × 95.7 = 3477.7 kJ

[0081] At this time, the explosion energy of gas cylinder 1 is equal to the explosion energy of 0.77kg of TNT.

[0082] In summary, the present application proposes a pressure testing device for reducing explosion energy, which can effectively reduce the explosion energy generated by accidental damage of the gas cylinder 1 during the low-temperature pressure test of the gas cylinder 1, and has a significant beneficial effect.

[0083] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0084] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0085] The above is only an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

[0086] Although the embodiments of the present application have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present application, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A low temperature pressure test device for reducing explosion energy, characterized in that: include: A gas cylinder having a first accommodation space; A flexible liner and a filling part, wherein the flexible liner and the filling part are both arranged in the first accommodation space, the flexible liner has a second accommodation space, and the filling part is arranged in the second accommodation space to support the flexible liner; The flexible liner is at least partially spaced apart from the inner wall of the gas cylinder to form a gap for accommodating the medium.

2. The low temperature pressure testing device according to claim 1, characterized in that: The pressure testing device further includes a positioning portion, which is disposed between the flexible liner and the inner wall of the gas cylinder to space the flexible liner from the inner wall of the gas cylinder.

3. The low temperature pressure testing device according to claim 2, characterized in that: The gas cylinder has a rotation axis, and along the length direction of the rotation axis, the gas cylinder includes a first straight section, a first arc section and a second arc section, and the first arc section and the second arc section are connected to two ends of the first straight section; Along the length direction of the rotation axis, the flexible liner includes a second straight section, a third arc section and a fourth arc section, and the third arc section and the fourth arc section are connected to two ends of the second straight section; The positioning portion includes a plurality of first positioning portions, and along the circumference of the gas cylinder, the plurality of first positioning portions are spaced between the first straight section and the second straight section to at least separate the first straight section from the second straight section.

4. The low temperature pressure testing device according to claim 3, characterized in that: The first positioning portion has a first through hole, and the first through hole penetrates the first positioning portion along the circumference of the gas cylinder.

5. The low temperature pressure testing device according to claim 4, characterized in that: The first through holes are multiple and are arranged at intervals along the rotation axis.

6. The low temperature pressure testing device according to claim 3, characterized in that: The positioning portion further includes a plurality of second positioning portions and a plurality of third positioning portions; Along the circumference of the gas cylinder, a plurality of the second positioning portions are spaced apart between the first arc segment and the third arc segment to at least separate the first arc segment from the third arc segment, and a plurality of the third positioning portions are spaced apart between the second arc segment and the fourth arc segment to separate the second arc segment from the fourth arc segment.

7. The low temperature pressure testing device according to claim 6, characterized in that: The second positioning portion has a second through hole, and the second through hole penetrates the second positioning portion along the circumference of the gas cylinder; The third positioning portion has a third through hole, and the third through hole penetrates the third positioning portion along the circumference of the gas cylinder.

8. The low temperature pressure testing device according to claim 1, characterized in that: The gas cylinder has an opening communicating with the first containing space, and the pressure testing device further comprises a connecting joint at least partially located in the opening; The connection joint has a first channel and a second channel, the first channel is communicated with the gap, and the second channel is communicated with the second accommodation space.

9. The low temperature pressure testing device according to claim 8, characterized in that: The number of the second channel is one, the number of the first channels is multiple, and the multiple first channels are arranged at intervals along the circumferential direction of the second channel.

10. The low temperature pressure testing device according to claim 1, characterized in that: The volume of the flexible liner is smaller than the volume of the accommodating space, and the ratio of the volume of the flexible liner to the volume of the first accommodating space is a, satisfying: a≥80%.

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