A low temperature pressure testing device for reducing the energy of an explosion

Abstract

The application relates to the technical field of gas cylinder pressure test, in particular to a low-temperature pressure test device for reducing blasting energy, wherein the low-temperature pressure test device comprises a gas cylinder, a flexible inner container and a filling part, the gas cylinder has a first containing space; the flexible inner container and the filling part are arranged in the first containing space, the flexible inner container has a second containing space, and the filling part is arranged in the second containing space to support the flexible inner container; wherein the flexible inner container is at least partially spaced apart from the inner wall of the gas cylinder to form a gap containing pressurized medium. The low-temperature pressure test device provided by the application solves the technical problem that a large amount of pressurized medium is filled in the gas cylinder, and the blasting energy is too large after the medium is vaporized, and the technical effect of reducing the blasting energy is achieved.

Description

TECHNICAL FIELD

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

[0002] Typical energy media usually has very high energy density when stored in the form of low-temperature liquid, and the storage and transportation equipment of low-temperature liquid energy has also become the direction of rapid development. The safety of the gas cylinder, as a common storage and transportation means for such low-temperature liquid, is also a key factor to ensure the safe storage and transportation of low-temperature liquid.

[0003] Low-temperature liquid has super-low temperature characteristics, and the pressure increase of the gas phase space caused by the heat absorption and vaporization of low-temperature liquid poses a great challenge to the pressure resistance performance of the gas cylinder under super-low temperature conditions. In the actual use process of the gas cylinder, when the low-temperature liquid absorbs heat and vaporizes to a certain pressure, the safety valve will be opened to release pressure in time to prevent the explosion of the gas cylinder caused by the increase of pressure. However, during the design and manufacture of the gas cylinder, it is necessary to carry out pressure test verification such as low-temperature explosion test, low-temperature hydrostatic test and low-temperature pressure cycle test, so as to fully evaluate the pressure safety of the gas cylinder in each stage of storing low-temperature liquid.

[0004] However, the low-temperature pressure test of the gas cylinder is a very dangerous test. In the test, low-temperature liquid is filled into the gas cylinder, and the pressure in the gas cylinder is controlled by compressing the low-temperature liquid. In the exploratory low-temperature pressure test, such as the low-temperature explosion test, the gas cylinder will explode instantly after the pressure rises to a certain pressure, and in the low-temperature pressure cycle test, the gas cylinder explodes instantly during a certain pressure rising process. The energy released instantly by the low-temperature liquid due to the sudden explosion of the gas cylinder is much higher than that in the conventional water pressure test or air pressure test.

[0005] Therefore, how to reduce the explosion energy caused by the accidental explosion of the gas cylinder in the low-temperature pressure test of the gas cylinder while ensuring the test of the pressure safety of the gas cylinder is the focus of attention at present. SUMMARY

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

[0007] In order to achieve the above purpose, the main technical scheme adopted by the present application includes:

[0008] The embodiment of the present application provides a low-temperature pressure test device for reducing blasting energy, which comprises a gas cylinder, a flexible inner container and a filling part, the gas cylinder has a first containing space; the flexible inner container and the filling part are arranged in the first containing space, the flexible inner container has a second containing space, and the filling part is arranged in the second containing space to support the flexible inner container; wherein the flexible inner container and the inner wall of the gas cylinder are at least partially spaced apart to form a gap for containing medium.

[0009] The pressure test device provided by the embodiment of the present application has the following advantages: the gas cylinder has a first containing space, the flexible inner container and the filling part are additionally arranged in the first containing space, the filling part is arranged in the second containing space of the flexible inner container and supports the flexible inner container, the volume of the flexible inner container after being supported by the filling part is smaller than the volume of the first containing space, the outer wall of the flexible inner container and the inner wall of the gas cylinder are at least partially spaced apart to form a gap, and medium is filled in the gap for pressure test. The volume of the gas cylinder for filling the pressurized medium for pressure test is reduced by arranging the flexible inner container and the filling part, the problem that the blasting energy is large due to the explosion of the gas cylinder caused by the vaporization of the medium filled in the gas cylinder is solved, and the blasting energy is reduced. Moreover, the filling part is arranged in the flexible inner container in the first containing space, the filling part and the flexible inner container are regarded as an integral structure, and the kinetic energy transmitted by instantaneous explosion is also reduced.

[0010] Optionally, the pressure test device further comprises a positioning part arranged between the flexible inner container and the inner wall of the gas cylinder to space apart the flexible inner container and the inner wall of the gas cylinder. The positioning part is arranged between the flexible inner container and the inner wall of the gas cylinder to space apart the flexible inner container and the inner wall of the gas cylinder, a gap is formed between the flexible inner container and the inner wall of the gas cylinder, the gap is filled with medium for pressure test, the volume of the gap is smaller than the volume of the gas cylinder, that is, the volume of the filled medium is reduced, and thus the energy generated by the explosion of the gas cylinder and the filled medium is reduced.

[0011] Optionally, the gas cylinder has a rotation axis, along the length direction of the rotation axis, the gas cylinder comprises a first straight section, a first arc section and a second arc section, the first arc section and the second arc section are connected to the two ends of the first straight section; along the length direction of the rotation axis, the flexible liner comprises a second straight section, a third arc section and a fourth arc section, the third arc section and the fourth arc section are connected to the two ends of the second straight section; the positioning part comprises a plurality of first positioning parts, along the circumferential direction of the gas cylinder, a plurality of first positioning parts are arranged 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 the second straight section of the flexible liner and the first straight section of the gas cylinder are provided with a plurality of first positioning parts spaced apart along the circumferential direction of the gas cylinder, the first positioning parts separate the first straight section and the second straight section to form a gap for filling the 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 of the medium in the gap are uniform.

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

[0013] Optionally, the first through hole is a plurality of and is arranged along the rotation axis. The first positioning part has a plurality of first through holes, so that the first positioning part as little as possible hinders the flow of the medium in the gap, ensures that the medium in the gap can flow sufficiently, and the medium in the gap is uniformly distributed.

[0014] Optionally, the positioning part further comprises a plurality of second positioning parts and a plurality of third positioning parts; along the circumference of the gas cylinder, the plurality of second positioning parts are arranged at intervals between the first arc-shaped section and the third arc-shaped section to at least separate the first arc-shaped section from the third arc-shaped section, and the plurality of third positioning parts are arranged at intervals between the second arc-shaped section and the fourth arc-shaped section to separate the second arc-shaped section from the fourth arc-shaped section. The plurality of second positioning parts arranged at intervals along the circumference of the gas cylinder between the first arc-shaped section and the third arc-shaped section separate the first arc-shaped section from the third arc-shaped section, and a gap is formed between the first arc-shaped section and the third arc-shaped section; the plurality of third positioning parts arranged at intervals along the circumference of the gas cylinder between the second arc-shaped section and the fourth arc-shaped section separate the second arc-shaped section from the fourth arc-shaped section, and a gap is formed between the second arc-shaped section and the fourth arc-shaped section. The arrangement of the plurality of first positioning parts, the plurality of second positioning parts, and the plurality of third positioning parts uniformly arranges the gaps between the inner wall of the gas cylinder and the outer wall of the flexible liner, so that the temperature and pressure distribution at each position in the gaps are uniform.

[0015] Optionally, the second positioning part has a second through hole penetrating the second positioning part along the circumference of the gas cylinder; and the third positioning part has a third through hole penetrating the third positioning part along the circumference of the gas cylinder. The second positioning part has a second through hole to enable sufficient flow of the medium at each position in the gap between the first arc-shaped section and the third arc-shaped section; and the third positioning part has a third through hole to enable sufficient flow of the medium at each position in the gap between the second arc-shaped section and the fourth arc-shaped section.

[0016] Optionally, the gas cylinder has an opening in communication with the first containing space, and the pressure test device further comprises 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 in communication with the gap, and the second channel is in communication with the second containing space. The medium is filled into the gap through the first channel, and the filling part is filled into the second containing space of the flexible liner through the second channel, and the filling part is used to support the flexible liner.

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

[0018] Optionally, the volume of the flexible liner is less than the volume of the first containing space, and the ratio of the volume of the flexible liner to the volume of the first containing space is a, which satisfies: a≥80%. The volume of the flexible liner is greater than or equal to 80% of the volume of the first containing space, which sufficiently 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 DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the specific embodiments or the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or the prior art description. Obviously, the drawings described below are some embodiments of the present application, and the drawings can also be obtained by those skilled in the art without any creative work.

[0020] Figure 1 It is a structural schematic diagram of the pressure test device of the present application.

[0021] Figure 2 It is a sectional schematic diagram of the pressure test device of the present application.

[0022] Figure 3 It is a structural schematic diagram of the opening of the gas cylinder of the pressure test device of the present application.

[0023]

Explanation of reference signs

[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 inner 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 solutions and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are some embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without any creative work belong to the scope of protection of the present application.

[0026] Unless otherwise defined, all the technical and scientific terms used in the present application have the same meanings as those commonly understood by those skilled in the art to which the present application belongs; the terms used in the present application are only for the purpose of describing the specific embodiments, and are not intended to limit the present application; the terms "include" and "have" and any variations thereof in the specification and claims of the present application and the above description of drawings are intended to cover not exclusive inclusion. The terms "first", "second" and the like in the specification and claims of the present application or the above description of drawings are used to distinguish different objects, and are not intended to describe a specific order or primary and secondary relationship.

[0027] Reference within this application to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive of one another. As will be apparent to one of ordinary skill in the art, embodiments described in this application can be combined with one another.

[0028] In the description of the application, it is necessary to point out that, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting", "attachment" should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0029] The term "and / or" in this application is only a description of the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B can represent the existence of A alone, the existence of A and B together, and the existence of B alone. In addition, the character " / " in this application generally represents that the front and rear associated objects have an "or" relationship.

[0030] "Multiple" appearing in this application means two or more (including two), and similarly, "multiple groups" means two or more groups (including two groups), and "multiple pieces" means two or more pieces (including two pieces).

[0031] Typical energy media such as hydrogen, oxygen, and methane usually have very high energy density when stored in low-temperature liquid form. The storage and transportation equipment of low-temperature liquid energy such as liquid hydrogen, liquid oxygen, and liquefied natural gas has also become a rapidly developing direction. The safety of gas cylinders, which are commonly used for the storage and transportation of such low-temperature liquids, is also a key factor in ensuring the safe storage and transportation of low-temperature liquids.

[0032] Low-temperature liquids have ultra-low temperature characteristics (liquid hydrogen -253℃, liquid oxygen -183℃, liquefied natural gas -162℃), and the pressure increase in the gas phase space caused by the heat absorption and vaporization of low-temperature liquids poses a huge challenge to the pressure resistance performance of gas cylinders under ultra-low temperature conditions. During actual use of the gas cylinder, when the low-temperature liquid absorbs heat and vaporizes to a certain pressure, the safety valve will be opened to release pressure in time to prevent the pressure from rising and causing the gas cylinder to burst. However, during the design and manufacture of the gas cylinder, pressure tests such as low-temperature burst test, hydrostatic test, and pressure cycle test need to be carried out to fully evaluate the pressure safety of the gas cylinder at each stage of storing low-temperature liquids.

[0033] However, the gas cylinder low-temperature pressure test is an extremely dangerous test. In the test, low-temperature liquids such as liquid hydrogen and liquid nitrogen are filled into the gas cylinder, and the pressure in the gas cylinder is controlled by compressing the low-temperature liquid. In the exploratory low-temperature pressure test, for example, in the low-temperature burst test, the gas cylinder will burst instantaneously after being raised to a certain pressure, and in the low-temperature pressure cycle test, the gas cylinder bursts instantaneously during a certain pressure raising process. The energy released instantaneously by the low-temperature liquid due to the sudden burst of the gas cylinder is much higher than that in the conventional water pressure test or the gas pressure test (for example, 1 unit of liquid nitrogen can expand to 696 units of nitrogen gas, and 1 unit of liquid hydrogen can expand to 788 units of hydrogen gas). According to the evaluation of the inventor team: for a 1000L gas cylinder, the burst energy at 3.2MPa pressure with liquid nitrogen as the low-temperature increasing medium will exceed 30MJ, which is equivalent to more than 7kg TNT explosive explosion.

[0034] Simply reducing the amount of liquid medium injected into the gas cylinder cannot well test the pressure safety of the gas cylinder. Therefore, how to reduce the burst energy caused by the accidental burst of the gas cylinder in the gas cylinder low-temperature pressure test while ensuring the test of the pressure safety of the gas cylinder is the focus at present.

[0035] In the related art, some schemes propose to add low-temperature resistant fillers compatible with the test medium to the gas cylinder. By reducing the internal volume of the gas cylinder, the amount of pressurizing medium added is reduced. For such a method, the energy released by the gas cylinder when it bursts at low temperature can indeed be reduced, but if the filler is in direct contact with the pressurizing medium, a huge initial kinetic energy will be provided to the filler at the moment of the gas cylinder burst, causing the filler to splash rapidly with the gas cylinder burst, causing more serious consequences. Moreover, the formation state of the filler in the gas cylinder is also difficult to control, and uneven filling will lead to local stress concentration in the gas cylinder and uneven distribution of internal pressure. In addition, the existing gas cylinder low-temperature pressure test is to cool the gas cylinder from the outside and to perform low-temperature pressure test by means of high-pressure gas inside the gas cylinder. In the test of directly pressurizing with low-temperature liquid, the burst energy will be much larger, and the related technical solutions are difficult to provide effective technical guidance for such tests.

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

[0037] Reference Figure 1 and Figure 2 The embodiment of the present application provides a low-temperature pressure test device for reducing blasting energy, which comprises a gas cylinder 1, a flexible inner container 2 and a filling part 3. The gas cylinder 1 has a first containing space. The flexible inner container 2 and the filling part 3 are arranged in the first containing space. The flexible inner container 2 has a second containing space, and the filling part 3 is arranged in the second containing space to support the flexible inner container 2. At least part of the flexible inner container 2 is spaced apart from the inner wall of the gas cylinder 1 to form a gap 10 for containing medium.

[0038] Specifically, the flexible inner container 2 is made of flexible material, and the flexible inner container 2 can maintain flexibility under normal temperature and low-temperature conditions and can be folded to enter the first containing space through the opening 14 of the gas cylinder 1. The material of the flexible inner container 2 can be at least one of polyimide, polytetrafluoroethylene, polystyrene or polyether ether ketone. The filling part 3 is arranged inside the flexible inner container 2 and is made of soft material that can be cured under certain conditions. The soft material has low-temperature resistance that does not crack at low-temperature medium temperature. For example, the filling part 3 can be expandable foaming material such as polystyrene foam, polyurethane foam, polyimide foam. It can also be injectable composite material such as acrylate composite material and polyurethane composite material, as long as the liquid or fluid can be injected into the flexible inner container 2 and foamed and cured under certain conditions. The filling part 3 forms a rigid support filling structure after being cured in the flexible inner container 2, which is used to maintain the shape of the flexible inner container 2 and provide the required structural rigidity for the flexible inner container 2 when the medium in the gap 10 is subjected to low-temperature pressurization. The pressure test device is suitable for low-temperature pressure test of the gas cylinder using low-temperature liquid pressurization. By arranging the flexible inner container 2 and the filling part 3 inside the gas cylinder 1, the volume of the low-temperature medium pressurization space is reduced, and the soft material used in the filling part 3 has energy absorption effect, which can further effectively reduce the blasting energy generated when the gas cylinder 1 is accidentally blasted.

[0039] The gas cylinder 1 can be a double-layer insulation gas cylinder, a fiber full-winding gas cylinder, a steel structure reinforced gas cylinder or a full-composite lightweight gas cylinder. The medium filled in the gap 10 can be single low-temperature liquid such as liquid nitrogen, liquid helium and liquid hydrogen, or can be multi-phase low-temperature liquid or low-temperature gas-liquid mixture such as liquid nitrogen, liquid helium, liquid hydrogen, hydrogen, helium and nitrogen.

[0040] The low-temperature pressure test device provided by the embodiment of the present application, the gas cylinder 1 has a first accommodating space, a flexible inner container 2 and a filling part 3 are additionally arranged in the first accommodating space, the filling part 3 is arranged in a second accommodating space of the flexible inner container 2, the volume of the flexible inner container 2 after being supported open by the filling part 3 is smaller than the volume of the first accommodating space, a gap 10 is formed between the outer wall of the flexible inner container 2 and the inner wall of the gas cylinder 1 at least partially, and a medium is filled in the gap 10 for pressure test. The volume of the medium filled in the gas cylinder 1 for pressure test is reduced by arranging the flexible inner container 2 and the filling part 3, the problem that a large amount of medium is filled in the gas cylinder, and a large amount of explosion energy is generated when the medium is vaporized and the gas cylinder is exploded is solved, and the explosion energy is reduced. Moreover, the filling part 3 is arranged in the flexible inner container 2 in the first accommodating space, and the filling part 3 and the flexible inner container 2 are taken as a whole structure, and the kinetic energy transmitted by instantaneous explosion is also reduced. That is to say, the uniformity of the internal pressure distribution of the gas cylinder 1 in the low-temperature pressure test can be ensured by arranging the flexible inner container 2 and the filling part 3, and the flexible inner container 2 and the filling part 3 can be taken as a uniform whole, and the kinetic energy transmitted by instantaneous explosion of the gas cylinder 1 can be reduced.

[0041] Optionally, the pressure test device further comprises a positioning part 4 arranged between the flexible inner container 2 and the inner wall of the gas cylinder 1 to space the flexible inner container 2 and the inner wall of the gas cylinder 1. The positioning part 4 can be attached to the outer wall of the flexible inner container 2 by means of gluing, welding or the like to space the flexible inner container 2 and the inner wall of the gas cylinder 1, and a gap 10 is formed between the flexible inner container 2 and the inner wall of the gas cylinder 1, 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 of the gas cylinder 1, that is, the volume of the medium is reduced, and thus the energy generated by the medium filled in the gap 10 when the gas cylinder 1 explodes is reduced. The positioning part 4 can be made of non-metallic materials such as polytetrafluoroethylene, polyethylene, polypropylene, polymethyl methacrylate or epoxy resin, or metallic materials such as stainless steel and aluminum alloy, as long as the positioning part 4 can be supported between the outer wall of the flexible inner container 2 and the inner wall of the gas cylinder 1 to form the gap 10 for accommodating the medium between the outer wall of the flexible inner container 2 and the inner wall of the gas cylinder 1.

[0042] Optionally, with reference to Figure 1, the gas cylinder 1 has a rotation axis 15, along the length direction of the rotation axis 15, the gas cylinder 1 comprises a first straight section 11, a first arc section 12 and a second arc section 13, 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 comprises a second straight section 21, a third arc section 22 and a fourth arc section 23, the third arc section 22 and the fourth arc section 23 are connected to both ends of the second straight section 21; the positioning part 4 comprises a plurality of first positioning parts 41, along the circumferential direction of the gas cylinder 1, the plurality of first positioning parts 41 are arranged at intervals between the first straight section 11 and the second straight section 21, so as to at least separate the first straight section 11 and 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, the fourth arc section 23 of the flexible liner 2 corresponds to the second arc section 13 of the gas cylinder 1, and the second straight section 21 of the flexible liner 2 and the first straight section 11 of the gas cylinder 1 are provided with a plurality of first positioning parts 41 which are spaced apart along the circumferential direction of the gas cylinder 1, the first positioning parts 41 separate the first straight section 11 and the second straight section 21 to form a gap 10 filled with a medium. The plurality of spaced-apart first positioning parts 41 allow the second straight section 21 of the flexible liner 2 to be located at the central position in the gas cylinder 1, and further allow the gap 10 between the first straight section 11 and the second straight section 21 to remain uniform and stable, thereby achieving uniform temperature and pressure distribution in the gap 10.

[0043] Optionally, the first positioning part 41 has a first through hole 410, and the first through hole 410 penetrates the first positioning part 41 along the circumferential direction of the gas cylinder 1. The first positioning part 41 has a first through hole 410 penetrating the first positioning part 41, that is, the first through hole 410 of each first positioning part 41 can be communicated along the circumferential direction of the gas cylinder 1, so that the medium filled in the gap 10 can flow sufficiently. In an optional embodiment, the first through hole 410 of each first positioning part 41 is correspondingly arranged along the circumferential direction 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, the first through hole 410 is multiple and is arranged along the rotation axis 15. Specifically, each first positioning part 41 extends along the length direction of the rotation axis 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 part 41 is close to the length of the second flat section 21. Along the length direction of the rotation axis 15, the first positioning part 41 has multiple first through holes 410 arranged at intervals, so that the first positioning part 41 as little as possible hinders the flow of the medium in the gap 10, and ensures that the medium in the gap 10 can flow fully and the medium distribution in the gap 10 is uniform. In an optional embodiment, multiple first positioning parts 41 are arranged at intervals along the circumference of the gas cylinder 1, and the first through holes 410 of the multiple first positioning parts 41 are arranged one by one on multiple planes perpendicular to the rotation axis 15, so that the low-temperature medium in the gap 10 can flow fully. Specifically, the first positioning part 41 has four, which are arranged at intervals along the circumference of the gas cylinder 1; each first positioning part 41 has three first through holes 410 arranged at intervals along the length direction of the rotation axis 15.

[0045] Optionally, the positioning part 4 further comprises multiple second positioning parts 42 and multiple third positioning parts 43; along the circumference of the gas cylinder 1, the multiple second positioning parts 42 are arranged at intervals between the first arc-shaped section 12 and the third arc-shaped section 22 to at least separate the first arc-shaped section 12 and the third arc-shaped section 22, and the multiple third positioning parts 43 are arranged at intervals between the second arc-shaped section 13 and the fourth arc-shaped section 23 to separate the second arc-shaped section 13 and the fourth arc-shaped section 23. The multiple second positioning parts 42 are arranged at intervals along the circumference of the gas cylinder 1 between the first arc-shaped section 12 and the third arc-shaped section 22, the second positioning parts 42 separate the first arc-shaped section 12 and the third arc-shaped section 22, and the gap 10 is formed between the first arc-shaped section 12 and the third arc-shaped section 22; the multiple third positioning parts 43 are arranged at intervals along the circumference of the gas cylinder 1 between the second arc-shaped section 13 and the fourth arc-shaped section 23, the third positioning parts 43 separate the second arc-shaped section 13 and the fourth arc-shaped section 23, and the gap 10 is formed between the second arc-shaped section 13 and the fourth arc-shaped section 23. The arrangement of the multiple first positioning parts 41, the multiple second positioning parts 42 and the multiple third positioning parts 43 enables the flexible liner 2 to be in 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 uniformly arranged, thereby realizing uniform temperature and pressure distribution in the gap 10.

[0046] Specifically, the flexible liner 2 can maintain flexibility under normal and low temperature conditions, and can be folded to be inserted into the gas cylinder 1 through the gas cylinder 1 opening. After the flexible liner 2 is inflated, the positioning portion 4 is in contact with the inner wall of the gas cylinder 1, and a gap 10 is formed between the inner wall of the gas cylinder 1 and the outer wall of the flexible liner 2, which is used to fill 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 and maintained in the central region of 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.

[0047] Optionally, the second positioning portion 42 has a second through hole 420, which 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, which 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 the gap 10 between the first arc-shaped section 12 and the third arc-shaped section 22 can flow sufficiently; the third positioning portion 43 has the third through hole 430, so that the medium in the gap 10 between the second arc-shaped section 13 and the fourth arc-shaped section 23 can flow sufficiently.

[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 uniformly arranged and installed in the circumference of the flexible liner 2. The thicknesses of the first positioning portion 41, the second positioning portion 42 and the third positioning portion 43 are the same, which ensures that the gap 10 between the outer wall of the flexible liner 2 and the inner wall of the gas cylinder 1 is uniform, and further ensures that the pressure distribution in the gap 10 is uniform, preventing stress concentration. The widths of the first positioning portion 41, the second positioning portion 42 and the third positioning portion 43 are also the same, 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 can flow sufficiently and uniformly.

[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, so that the low-temperature medium in the gap 10 can flow more sufficiently.

[0050] Optionally, referring to Figure 3 , the gas cylinder 1 has an opening 14 communicating with the first containing space, and the pressure test device further comprises a connecting joint 5 at least partially located in the opening 14; the connecting joint 5 has a first channel 51 and a second channel 52, the first channel 51 communicates with the gap 10, and the second channel 52 communicates with the second containing 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 containing space of the flexible liner 2 through the second channel 52 to form the filling portion 3, which is used to support the flexible liner 2.

[0051] Optionally, the second channel 52 is one, and the first channels 51 are multiple, and the multiple first channels 51 are arranged along the circumference of the second channel 52. The first channels 51 are arranged along 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, the valve seat is fixed with the opening 14 of the flexible liner 2 by gluing, the center of the valve seat is provided with a second channel 52 for inflating and filling the filling part 3; a first channel 51 is arranged outside the second channel 52 and uniformly distributed along the circumference of the second channel 52, which is in communication with the low-temperature medium pressure space and is used for low-temperature medium filling and pressure control in the low-temperature pressure test of the cylinder 1. That is, the soft material enters the flexible liner 2 through the second channel 52 at the valve seat of the flexible liner 2, and after solidification inside the flexible liner 2, the filling part 3 with rigidity is formed, 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 with the flexible liner 2 is connected with the opening 14 of the cylinder 1, which avoids 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 less than the volume of the first containing space, and the ratio of the volume of the flexible liner 2 to the volume of the first containing space is a, which satisfies: a≥80%. The volume of the flexible liner 2 is greater than or equal to 80% of the volume of the first containing space, which sufficiently reduces the volume of the medium in the gap 10, thereby achieving the purpose of reducing the burst energy of the cylinder 1.

[0054] The pressure test device provided in the present application, the flexible liner 2 and the surface positioning part 4 thereof can easily enter the inside of the cylinder 1 by folding, and the flexible liner 2 is provided with a valve seat at one end, which is convenient for connecting with the opening 14 of the cylinder 1; after the valve seat is fixed, the filling part 3 and the gap 10 are independent of each other, and the overall installation of the device is efficient and convenient.

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

[0056] The structure of the flexible liner 2 and the positioning part 4 thereof is as follows: Figure 2 The shape of the flexible liner 2 is similar to that of the cylinder 1, and the outer wall surface of the flexible liner 2 is provided with a flexible liner 2 positioning part 4. After the flexible liner 2 is inflated, the positioning part 4 contacts the inner wall surface of the cylinder 1, thereby realizing the positioning of the flexible liner 2 in the inside of the cylinder 1.

[0057] Valve seat structure reference of the end of the flexible liner 2 Figure 3 That is to say, the first channel 51 connects the gap between the outer wall of the flexible liner 2 and the inner wall of the gas cylinder 1, and the second channel 52 connects the second accommodating cavity of the flexible liner 2. After the flexible liner 2 is inserted into the inside of the gas cylinder 1, the inside of the flexible liner 2 is filled with gas through the second channel 52, after the flexible liner 2 is inflated, the soft material or foaming material that can be solidified under certain conditions is added to the inside of the flexible liner 2 through the second channel 52, and the soft material or foaming material is fully solidified to form the filling part 3; during the low-temperature pressure test of the gas cylinder 1, the first channel 51 is connected with the external low-temperature medium filling pipeline, and after the first channel 51 is fully filled with low-temperature medium, the pressure of the gas cylinder 1 is increased 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 burst energy in the development test link of a vehicle-mounted liquefied natural gas (LNG) cylinder 1.

[0059] A commercial heavy truck is equipped with a vehicle-mounted LNG cylinder with a volume of 1000L. The vehicle-mounted LNG cylinder adopts a double-layer stainless steel cylinder structure, wherein the inner layer stainless steel cylinder is a storage carrier for LNG, the high-vacuum thermal insulation layer between the inner and outer layers is used to ensure the adiabatic storage of LNG, and the outer shell is used to ensure the integrity of the high-vacuum thermal insulation layer. The effective volume of the inner layer stainless steel cylinder (hereinafter referred to as cylinder 1) is 1000L, the outer diameter of the cylinder 1 is 850mm, the length of the first flat section 11 of the cylinder 1 is 1500mm, the wall thickness is 6mm, and the design nominal working pressure is 1.6MPa. In order to test the pressure safety of the cylinder 1 storing ultra-low temperature LNG medium, a low-temperature pressure test needs to be carried out on the cylinder 1.

[0060] In the low-temperature pressure test of the cylinder, the pressure test device for reducing burst energy proposed in the present application is first assembled. The flexible liner 2 is made of polyimide material and is formed by hot pressing technology. The shape of the polyimide liner is similar to that of the cylinder 1. The outer diameter of the flexible liner 2 is 800mm, the length of the second flat section 21 of the flexible liner 2 is 1500mm, the wall thickness is 3mm, the effective volume is 890L, and the volume of the space inside the cylinder 1 for low-temperature medium pressurization after the installation of the flexible liner 2 is 110L.

[0061] The outer wall surface of the flexible liner 2 is provided with a positioning portion 4 for positioning the flexible liner 2, and the positioning portion 4 is made of an epoxy resin plate and is fixed to the outer wall surface of the flexible liner 2 by means of adhesion. The first positioning portion 41 at the second straight section 21 of the flexible liner 2 has a cuboid structure, the length thereof along the rotation axis 15 of the gas cylinder is 1300 mm, the circumferential width is 30 mm, and the radial thickness is 50 mm, and the first positioning portion 41 at the second straight section 21 is provided with three first through holes 410 for the flow of low-temperature medium, the length of each first through hole 410 along the rotation axis 15 of the gas cylinder is 320 mm, the radial height is 30 mm, and the circumferential direction is completely penetrated. The second positioning portion 42 of the third arc-shaped section 22 has a fan ring structure consistent with the curve shape of the first arc-shaped section 12, and the third positioning portion 43 of the fourth arc-shaped section 23 has a fan ring structure consistent with the curve shape of the second arc-shaped section 13, the arc length of the second positioning portion 42 and the third positioning portion 43 is 520 mm, the circumferential width is 30 mm, and the radial thickness is 50 mm, the second positioning portion 42 at the third arc-shaped section 22 has a second through hole 420, and the third positioning portion 43 at the fourth arc-shaped section 23 has a third through hole 430, the arc length of the second through hole 420 and the third through hole 430 is 400 mm, the radial height is 30 mm, and the circumferential direction is completely penetrated. The first positioning portion 41, the second positioning portion 42 and the third positioning portion 43 are uniformly spaced in the circumferential direction of the gas cylinder 1 at 0 degrees, 90 degrees, 180 degrees and 270 degrees.

[0062] After the flexible liner 2 is formed and the positioning portion 4 is installed, one end of the flexible liner 2 is bonded and fixed to the valve seat using an acrylic adhesive. The other end of the flexible liner 2 is inserted into the interior of the gas cylinder 1, and after complete insertion, the valve seat is threadedly connected to the opening 14 of the gas cylinder 1. The flexible liner 2 is fully inflated by inflating the center second passage 52 of the valve seat, and the positioning portion 4 on the flexible liner 2 is in full contact with the inner wall surface of the gas cylinder 1, and then 40℃ polyurethane foaming mixture is introduced from the center second passage 52 of the valve seat, so that it spontaneously and uniformly foams in the interior of the flexible liner 2 to form a dense and high-rigid polyurethane rigid foam as the filling portion 3.

[0063] The flexible liner 2 and the filling portion 3 formed by the polyurethane rigid foam are located in the gas cylinder 1, and in the low-temperature pressure test of the gas cylinder, liquid nitrogen is used as the pressurizing medium, and liquid nitrogen is added from the multiple first passages 51 of the valve seat in a bidirectional filling manner, that is, the gas or low-temperature nitrogen gas evaporated by heat absorption is removed in real time during the process of liquid nitrogen filling, until the low-temperature medium pressurizing space is completely filled with liquid nitrogen, and the liquid nitrogen burst test is started until the gas cylinder 1 is completely destroyed.

[0064] The above embodiment is the design and installation steps of the pressure test device for reducing the blasting energy, and the supporting gas cylinder low temperature pressure test process. Considering that the blasting energy of the gas cylinder 1 is difficult to measure by test, the boiling liquid expanding vapor explosion model is used to estimate the energy change of the gas cylinder 1 under the liquid nitrogen blasting before and after the test using the pressure test device of the application:

[0065] The test pressure (minimum bursting pressure) of the 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 the gas cylinder 1 is 1.6 MPa, the theoretical bursting pressure is about 3.2 MPa. At the moment of the destruction of the gas cylinder 1, the released energy makes the liquid nitrogen in a superheated state, at which time the energy released by the superheated liquid nitrogen at the time of the explosion of the gas cylinder 1 is calculated according to the following formula:

[0066]

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

[0068] ①For the gas cylinder 1 not using the pressure test device of the application, the effective volume is 1000L, and at the time of 3.2MPa 77K liquid nitrogen low temperature explosion:

[0069] The mass of the 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] Entropy difference multiplied by 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=31615.8kJ

[0074] The average blasting energy released by 1kg of TNT explosion is generally defined as 4500 kJ / kg, at which time the blasting energy of the gas cylinder 1 is equal to the explosion energy of 7.0kg of TNT.

[0075] 2. For the gas cylinder 1 using the pressure test device of the present application, the effective volume is 110L, and when the low-temperature explosion of 3.2MPa 77K liquid nitrogen occurs:

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

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

[0078] Entropy difference multiplied by 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=3477.7kJ

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

[0082] In summary, the pressure test device for reducing explosion energy is proposed in the present application, which can effectively reduce the explosion energy caused by the accidental damage of the gas cylinder 1 in the low-temperature pressure test of the gas cylinder 1, and has significant beneficial effects.

[0083] It should be further noted that the terms "comprising", "containing" or any other variant thereof are intended to cover non-exclusive inclusions, such that processes, methods, articles or devices that comprise a list of elements do not exclude other elements not explicitly listed, or other elements inherent to such processes, methods, articles or devices. Without more limitations, the element defined by the statement "comprising a" does not exclude the presence of additional identical elements in the process, method, article or device that includes the element.

[0084] Each embodiment in the specification is described in a progressive manner, and the same or similar parts between each embodiment can be referred to each other, and each embodiment focuses on the difference from other embodiments.

[0085] The above only describes the embodiments of the present application and is not intended to limit the present application. The present application can have various changes and modifications for those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the scope of the claims of the present application.

[0086] While embodiments of the application have been described in connection with the preferred embodiments of the various figures, those of ordinary skill in the art will appreciate that various modifications and changes can be made without departing from the spirit and scope of the application, and that such modifications and changes fall within the scope of the appended claims.

Claims

1. A low temperature pressure test device for reducing blasting energy, characterized in that: include: A gas cylinder having a first accommodation space; A flexible liner and a filling portion, wherein the flexible liner and the filling portion are both arranged in the first accommodation space, the flexible liner has a second accommodation space, the filling portion is arranged in the second accommodation space to support the flexible liner, and the filling portion is constructed of a soft material that can expand and solidify; 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 separate 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. 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. 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. Along the circumference of the gas cylinder, the plurality of first positioning portions are spaced apart 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: There are a plurality of first through holes, which are spaced apart 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, multiple 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 multiple 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 passes through 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 passes through 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 accommodation space, and the pressure testing device further comprises 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 communicated with the gap, and the second channel is communicated with the second accommodating space.

9. The low temperature pressure testing device according to claim 8, characterized in that: There is one second channel, and there are multiple first channels, and the multiple first channels are spaced apart along the circumference 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 first accommodating space. The ratio of the volume of the flexible liner to the volume of the first accommodating space is a, and satisfies: a≥80%.

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