Gas cylinder fatigue test system and method with variable environment temperature

Abstract

The invention relates to the technical field of gas cylinder performance testing, and discloses a variable environment temperature gas cylinder fatigue testing system, which comprises a gas cylinder testing device and a pressure adjusting device, the gas cylinder testing device is characterized in that a tested gas cylinder is arranged in an environment simulation cabin and is connected with the pressure adjusting device, the environment simulation cabin is connected with an electric heater, and the electric heater is connected with a gas distribution chamber; the gas distribution chamber is respectively connected with a normal-temperature nitrogen source and a liquid nitrogen storage tank; when testing is carried out at the temperature lower than the environment temperature, liquid nitrogen in the liquid nitrogen storage tank enters the gas distribution chamber and is mixed with normal-temperature nitrogen from the normal-temperature nitrogen source, and after the target temperature is reached, low-temperature nitrogen in the gas distribution chamber enters the environment simulation cabin to create the target environment temperature; when testing is carried out at the temperature higher than the environment temperature, gas is input into the gas distribution chamber through the normal-temperature nitrogen source, heated by the electric heater and then conveyed into the environment simulation cabin, and the target environment temperature is created. According to the invention, the gas cylinder fatigue test can be carried out in the environment of-70 DEG C to 100 DEG C, the obtained test result is more comprehensive, and the safety of the test result is higher.

Description

Technical Field

[0001] The invention relates to the technical field of gas cylinder performance testing, and in particular to a gas cylinder fatigue testing system and method with variable ambient temperature. Background Art

[0002] As the clean energy with the greatest development potential in the 21st century, hydrogen energy occupies a pivotal position in the energy revolution. At present, my country's hydrogen energy-related industries have entered a period of rapid development, and hydrogen energy vehicles and hydrogen energy aviation industries are booming. However, this is accompanied by public concerns about the safety of hydrogen energy applications. At present, the main way of hydrogen energy storage in my country is high-pressure gaseous hydrogen storage, using hydrogen cylinders as containers. Hydrogen cylinders need to undergo rigorous performance tests before delivery from the factory, and fatigue testing is the most common test content.

[0003] At present, fatigue tests on gas cylinders are all carried out at room temperature. However, in actual use, it is not possible to completely guarantee that the gas cylinders are always in a room temperature environment. Changes in ambient temperature will affect the properties of the cylinder body material, thereby changing the life of the cylinder. Therefore, it is not enough to conduct fatigue tests only at room temperature. It is necessary to increase fatigue tests at extreme ambient temperatures that may occur during the use of gas cylinders. Summary of the invention

[0004] The present invention provides a gas cylinder fatigue test system and method with variable ambient temperature, which can perform gas cylinder fatigue test in an environment of -70°C to 100°C, and the obtained test results are more comprehensive and safer.

[0005] The present invention provides a gas cylinder fatigue testing system with variable ambient temperature, comprising a gas cylinder testing device and a pressure regulating device, wherein the pressure regulating device is connected to the gas cylinder testing device;

[0006] The gas cylinder testing device comprises a test gas cylinder, an environmental simulation cabin, an electric heater, a gas distribution chamber, a normal temperature nitrogen source, and a liquid nitrogen storage tank. The test gas cylinder is arranged in the environmental simulation cabin and connected to the pressure adjustment device. The environmental simulation cabin is connected to the electric heater, and the electric heater is connected to the gas distribution chamber. The gas distribution chamber is respectively connected to the normal temperature nitrogen source and the liquid nitrogen storage tank.

[0007] When fatigue testing is required in an environment below ambient temperature, the liquid nitrogen in the liquid nitrogen storage tank enters the gas distribution chamber and is mixed with the normal temperature nitrogen from the normal temperature nitrogen source. After reaching the target temperature, the low temperature nitrogen in the gas distribution chamber enters the environmental simulation cabin, thereby creating a target ambient temperature around the test gas cylinder;

[0008] When fatigue testing is required in an environment with a temperature higher than the ambient temperature, only gas is input into the gas distribution chamber through the normal-temperature nitrogen source, and after being heated by the electric heater, it is transported into the environmental simulation chamber, so as to create a target environmental temperature around the test gas cylinder.

[0009] Further, an electrically controlled valve is provided between the liquid nitrogen storage tank and the gas distribution chamber. A part of the pipeline of the electrically controlled valve close to the gas distribution chamber is inserted into the gas distribution chamber, and the inserted pipeline part serves as a spray pipeline. The bottom of the spray pipeline is provided with holes so that the liquid nitrogen in the liquid nitrogen storage tank enters the gas distribution chamber in a spray manner;

[0010] The electrically controlled valve also adjusts the flow rate of the liquid nitrogen entering the gas distribution chamber by adjusting its own opening degree, so as to realize the adjustment of the gas temperature in the gas distribution chamber.

[0011] Further, a seventh manual stop valve is also provided between the normal-temperature nitrogen source and the gas distribution chamber. A sixth manual stop valve and a safety valve are sequentially connected between the test gas cylinder and the pressure adjustment device.

[0012] Further, the pressure adjustment device includes an oil tank, a pre-stage oil pump, a high-pressure oil pump, a one-way valve, a third pneumatic valve, and a first pneumatic valve. The oil tank is respectively connected to the pre-stage oil pump, one end of the first pneumatic valve, and one end of the third pneumatic valve. The pre-stage oil pump is connected to the inlet end of the high-pressure oil pump. The outlet end of the high-pressure oil pump converges with the other end of the third pneumatic valve and is connected to one end of the one-way valve. The other end of the first pneumatic valve converges with the other end of the one-way valve and is connected to the safety valve;

[0013] During the gas cylinder pressurization stage, the hydraulic oil in the oil tank flows through the pre-stage oil pump, the high-pressure oil pump, and the one-way valve into the test gas cylinder to pressurize the gas cylinder;

[0014] During the high-pressure holding stage of the gas cylinder, the third pneumatic valve is opened, and the hydraulic oil circulates along the oil tank circulation loop composed of the oil tank, the high-pressure oil pump, and the third pneumatic valve, while the high-pressure hydraulic oil in the test gas cylinder is blocked by the one-way valve to maintain the high pressure in the test gas cylinder;

[0015] During the gas cylinder depressurization stage, the first pneumatic valve is opened, and the pressure in the test gas cylinder is discharged to the oil tank through the first pneumatic valve;

[0016] During the low-pressure holding stage of the gas cylinder, the first pneumatic valve is closed, and the hydraulic oil still circulates along the oil tank circulation loop composed of the oil tank, the high-pressure oil pump, and the third pneumatic valve.

[0017] Further, the fuel tank is also provided with a fuel tank inlet valve. An oil cooler is arranged between the fuel tank and the first pneumatic valve and the third pneumatic valve. A solenoid valve is arranged between the fuel tank and the pre - oil pump. A filter is arranged between the pre - oil pump and the high - pressure oil pump. The high - pressure oil pump is also connected with a high - pressure oil pump cooler.

[0018] Further, a fourth manual stop valve is arranged between the third pneumatic valve and the check valve. A second manual stop valve is arranged between the first pneumatic valve and the check valve. One end of the first pneumatic valve away from the second manual stop valve and one end of the second manual stop valve away from the first pneumatic valve are connected in parallel with the first manual stop valve.

[0019] Further, one end of the first pneumatic valve away from the second manual stop valve and one end of the second manual stop valve away from the first pneumatic valve are connected in parallel with a second pneumatic valve and a third manual stop valve. The second pneumatic valve serves as a standby valve for the first pneumatic valve, and the third manual stop valve serves as a standby valve for the second manual stop valve;

[0020] One end of the third pneumatic valve away from the fourth manual stop valve and one end of the fourth manual stop valve away from the third pneumatic valve are connected in parallel with a fourth pneumatic valve and a fifth manual stop valve. The fourth pneumatic valve serves as a standby valve for the third pneumatic valve, and the fifth manual stop valve serves as a standby valve for the fourth manual stop valve.

[0021] Further, an explosion - proof facility for preventing the gas cylinder from bursting during the fatigue test is arranged between the check valve and the sixth manual stop valve, so that the explosion - proof facility is located between the pressure adjustment device and the gas cylinder test device.

[0022] The present invention also provides a method for fatigue testing of gas cylinders with variable ambient temperature, based on the above - mentioned fatigue testing system for gas cylinders with variable ambient temperature, including:

[0023] S1. Except for the seventh manual stop valve and the standby valves, all the manual stop valves in the system are in the open state;

[0024] S2. First, connect the test gas cylinder to the system, and open the seventh manual stop valve to conduct nitrogen replacement for the gas distribution chamber and the environmental simulation chamber;

[0025] S3. After the nitrogen replacement is completed, configure the environmental simulation chamber to the target environmental temperature; specifically including:

[0026] When fatigue tests need to be carried out in an environment with a temperature lower than the ambient temperature, liquid nitrogen in the liquid nitrogen storage tank enters the gas distribution chamber and mixes with the normal-temperature nitrogen gas from the normal-temperature nitrogen gas source. After reaching the target temperature, the low-temperature nitrogen gas in the gas distribution chamber enters the environmental simulation chamber, thereby creating a target environmental temperature around the test gas cylinder;

[0027] When fatigue tests need to be carried out in an environment with a temperature higher than the ambient temperature, only the gas is input into the gas distribution chamber through the normal-temperature nitrogen gas source, and after being heated by the electric heater, it is transported into the environmental simulation chamber, thereby creating a target environmental temperature around the test gas cylinder;

[0028] S4. Start the pre-stage oil pump and the high-pressure oil pump to conduct gas cylinder fatigue tests, which specifically include the gas cylinder pressure increase stage, the gas cylinder high-pressure pressure holding stage, the gas cylinder pressure decrease stage, and the gas cylinder low-pressure pressure holding stage:

[0029] In the gas cylinder pressure increase stage, the hydraulic oil in the fuel tank flows through the pre-stage oil pump, the high-pressure oil pump, and the one-way valve into the test gas cylinder to increase the pressure of the gas cylinder;

[0030] In the gas cylinder high-pressure pressure holding stage, the third pneumatic valve opens, and the hydraulic oil circulates along the fuel tank circulation loop composed of the fuel tank, the high-pressure oil pump, and the third pneumatic valve, while the high-pressure hydraulic oil in the test gas cylinder is blocked by the one-way valve to maintain the high pressure in the test gas cylinder;

[0031] In the gas cylinder pressure decrease stage, the first pneumatic valve opens, and the pressure in the test gas cylinder is released into the fuel tank through the first pneumatic valve;

[0032] In the gas cylinder low-pressure pressure holding stage, the first pneumatic valve closes, and the hydraulic oil still circulates along the fuel tank circulation loop composed of the fuel tank, the high-pressure oil pump, and the third pneumatic valve.

[0033] The beneficial effects of the present invention are:

[0034] The present invention includes a gas cylinder testing device and a pressure adjustment device. Among them, the gas cylinder testing device includes: a test gas cylinder is arranged in an environmental simulation chamber and connected to the pressure adjustment device. The environmental simulation chamber is connected to an electric heater, and the electric heater is connected to a gas distribution chamber. The gas distribution chamber is respectively connected to a normal temperature nitrogen source and a liquid nitrogen storage tank. When fatigue testing is required in an environment below the ambient temperature, the liquid nitrogen in the liquid nitrogen storage tank enters the gas distribution chamber and mixes with the normal temperature nitrogen from the normal temperature nitrogen source. After reaching the target temperature, the low-temperature nitrogen in the gas distribution chamber enters the environmental simulation chamber, thereby creating a target environmental temperature around the test gas cylinder. When fatigue testing is required in an environment above the ambient temperature, only the gas is input into the gas distribution chamber through the normal temperature nitrogen source, and after being heated by the electric heater, it is transported into the environmental simulation chamber, thereby creating a target environmental temperature around the test gas cylinder. Finally, the present invention can perform gas cylinder fatigue testing in an environment of -70°C to 100°C, and the obtained test results are more comprehensive and the test results are safer. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic structural diagram of a gas cylinder fatigue testing system with variable environmental temperature according to the present invention.

[0036] In the drawings, fuel tank 1, fuel tank inlet valve 2, oil cooler 3, first pneumatic valve 4, second pneumatic valve 5, third pneumatic valve 6, fourth pneumatic valve 7, first manual stop valve 8, second manual stop valve 9, third manual stop valve 10, fourth manual stop valve 11, fifth manual stop valve 12, solenoid valve 13, pre-positioned oil pump 14, filter 15, high-pressure oil pump 16, check valve 17, high-pressure oil pump cooler 18, explosion-proof facility 19, sixth manual stop valve 20, safety valve 21, test gas cylinder 22, environmental simulation chamber 23, electric heater 24, gas distribution chamber 25, seventh manual stop valve 26, normal temperature nitrogen source 27, electric control valve 28, liquid nitrogen storage tank 29.

[0037] The realization, functional characteristics and advantages of the object of the present invention will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0038] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0039] As Figure 1 shown, the present invention provides a gas cylinder fatigue testing system with variable environmental temperature, including a gas cylinder testing device and a pressure adjustment device, and the pressure adjustment device is connected to the gas cylinder testing device.

[0040] (1) Gas cylinder testing device:

[0041] The gas cylinder testing device includes a test gas cylinder 22, an environmental simulation chamber 23, an electric heater 24, a gas distribution chamber 25, a normal temperature nitrogen source 27, and a liquid nitrogen storage tank 29. The test gas cylinder 22 is arranged in the environmental simulation chamber 23 and connected to the pressure adjustment device. The environmental simulation chamber 23 is connected to the electric heater 24, the electric heater 24 is connected to the gas distribution chamber 25, and the gas distribution chamber 25 is respectively connected to the normal temperature nitrogen source 27 and the liquid nitrogen storage tank 29. Among them, the fuel tank 1 is used to load the hydraulic oil for fatigue testing, and the hydraulic oil will be filled into the test gas cylinder 22 by the pre-stage oil pump 14 and the high-pressure oil pump 16. The pre-stage oil pump 14 is used to boost the pressure of the hydraulic oil to the inlet pressure required by the high-pressure oil pump 16.

[0042] In one embodiment, an electric control valve 28 is arranged between the liquid nitrogen storage tank 29 and the gas distribution chamber 25. A part of the pipeline of the electric control valve 28 close to the gas distribution chamber 25 is inserted into the gas distribution chamber 25, and the inserted pipeline part serves as a spray pipeline. The bottom of the spray pipeline is provided with holes so that the liquid nitrogen in the liquid nitrogen storage tank 29 enters the gas distribution chamber 25 in a spray manner. The electric control valve 28 also adjusts the flow rate of the liquid nitrogen entering the gas distribution chamber 25 by adjusting its own opening degree, so as to realize the adjustment of the gas temperature in the gas distribution chamber 25.

[0043] In one embodiment, a seventh manual stop valve 26 is further arranged between the normal temperature nitrogen source 27 and the gas distribution chamber 25. A sixth manual stop valve 20 and a safety valve 21 are successively connected between the test gas cylinder 22 and the pressure adjustment device.

[0044] The test gas cylinder 22 is located in the environmental simulation chamber 23, and the environmental simulation chamber 23 can simulate the environmental temperature in the temperature range of -70°C to 100°C. The simulation method is as follows:

[0045] a. When fatigue testing is required in an environment with a temperature lower than the ambient temperature, the liquid nitrogen from the liquid nitrogen storage tank 29 is made to enter the gas distribution chamber 25 in a spray manner and mix with the normal temperature nitrogen from the normal temperature nitrogen source 27. The electric control valve 28 adjusts the flow rate of the liquid nitrogen entering the gas distribution chamber 25 by adjusting its own opening degree, so as to realize the adjustment of the gas temperature in the gas distribution chamber 25. After reaching the target temperature, the low-temperature nitrogen in the gas distribution chamber 25 enters the environmental simulation chamber 23, and the environmental simulation chamber 23 is insulated by foaming to reduce the heat exchange with the external environment, so as to create a target environmental temperature around the test gas cylinder 22 located in the environmental simulation chamber 23.

[0046] b. When fatigue testing is required in an environment with a temperature higher than the ambient temperature, only the gas is input into the gas distribution chamber 25 through the normal temperature nitrogen source 27, and after being heated by the electric heater 24, it is transported into the environmental simulation chamber 23, so as to create a target environmental temperature around the test gas cylinder 22.

[0047] (2) Pressure adjustment device

[0048] The pressure adjustment device includes an oil tank 1, a pre - oil pump 14, a high - pressure oil pump 16, a check valve 17, a third pneumatic valve 6, and a first pneumatic valve 4. The oil tank 1 is respectively connected to one end of the pre - oil pump 14, one end of the first pneumatic valve 4, and one end of the third pneumatic valve 6. The pre - oil pump 14 is connected to the inlet end of the high - pressure oil pump 16. The outlet end of the high - pressure oil pump 16 converges with the other end of the third pneumatic valve 6 and is connected to one end of the check valve 17. The other end of the first pneumatic valve 4 converges with the other end of the check valve 17 and is connected to the safety valve 21.

[0049] In one embodiment, the oil tank 1 is further provided with an oil tank inlet valve 2. An oil cooler 3 is arranged between the oil tank 1 and the first pneumatic valve 4 and the third pneumatic valve 6. A solenoid valve 13 is arranged between the oil tank 1 and the pre - oil pump 14. A filter 15 is arranged between the pre - oil pump 14 and the high - pressure oil pump 16. The high - pressure oil pump 16 is also connected to a high - pressure oil pump cooler 18.

[0050] In one embodiment, a fourth manual stop valve 11 is arranged between the third pneumatic valve 6 and the check valve 17. A second manual stop valve 9 is arranged between the first pneumatic valve 4 and the check valve 17. One end of the first pneumatic valve 4 away from the second manual stop valve 9 and the end of the second manual stop valve 9 away from the first pneumatic valve 4 are connected in parallel with a first manual stop valve 8.

[0051] Since the fatigue test involves the repeated opening and closing of related valves, which may cause problems with the valves during use, standby valves are set for the valves that frequently operate. That is, one end of the first pneumatic valve 4 away from the second manual stop valve 9 and the end of the second manual stop valve 9 away from the first pneumatic valve 4 are connected in parallel with a second pneumatic valve 5 and a third manual stop valve 10; one end of the third pneumatic valve 6 away from the fourth manual stop valve 11 and the end of the fourth manual stop valve 11 away from the third pneumatic valve 6 are connected in parallel with a fourth pneumatic valve 7 and a fifth manual stop valve 12.

[0052] The second pneumatic valve 5 serves as the standby valve for the first pneumatic valve 4, and the third manual stop valve 10 serves as the standby valve for the second manual stop valve 9; the fourth pneumatic valve 7 serves as the standby valve for the third pneumatic valve 6, and the fifth manual stop valve 12 serves as the standby valve for the fourth manual stop valve 11.

[0053] In one embodiment, an explosion-proof facility 19 is provided between the one-way valve 17 and the sixth manual stop valve 20, so that the explosion-proof facility 19 is present between the pressure adjustment device and the gas cylinder testing device. The explosion-proof facility 19 is used to prevent the gas cylinder from bursting during the fatigue test, causing a safety accident.

[0054] The pressure adjustment process of the pressure adjustment device is as follows:

[0055] a. During the gas cylinder pressurization stage, the hydraulic oil in the oil tank 1 flows through the pre-stage oil pump 14, high-pressure oil pump 16 and one-way valve 17 into the test gas cylinder 22 to pressurize the gas cylinder.

[0056] b. During the high-pressure pressure holding stage of the gas cylinder, the third pneumatic valve 6 is opened, and the hydraulic oil circulates along the oil tank circulation loop composed of the oil tank 1, high-pressure oil pump 16 and third pneumatic valve 6, while the high-pressure hydraulic oil in the test gas cylinder 22 is blocked by the one-way valve 17 to maintain the high pressure in the test gas cylinder 22.

[0057] c. During the gas cylinder depressurization stage, the first pneumatic valve 4 is opened, and the pressure in the test gas cylinder 22 is released to the oil tank 1 through the first pneumatic valve 4.

[0058] d. During the low-pressure pressure holding stage of the gas cylinder, the first pneumatic valve 4 is closed, and the hydraulic oil still circulates along the oil tank circulation loop composed of the oil tank 1, high-pressure oil pump 16 and third pneumatic valve 6.

[0059] The present invention also provides a gas cylinder fatigue test method with variable ambient temperature, based on the gas cylinder fatigue test system with variable ambient temperature as described above, including:

[0060] S1. Except for the seventh manual stop valve 26 and the standby valve, all manual stop valves in the system are in the open state.

[0061] S2. First, connect the test gas cylinder 22 to the system, and open the seventh manual stop valve 26 to perform nitrogen replacement on the gas distribution chamber 25 and the environmental simulation chamber 23.

[0062] S3. After the nitrogen replacement is completed, configure the environmental simulation chamber 23 to the target environmental temperature; specifically including:

[0063] When a fatigue test needs to be carried out in an environment below the ambient temperature, the liquid nitrogen in the liquid nitrogen storage tank 29 enters the gas distribution chamber 25 and is mixed with the normal-temperature nitrogen from the normal-temperature nitrogen source 27. After reaching the target temperature, the low-temperature nitrogen in the gas distribution chamber 25 enters the environmental simulation chamber 23, thereby creating a target environmental temperature around the test gas cylinder 22.

[0064] When a fatigue test needs to be carried out in an environment with a temperature higher than the ambient temperature, only gas is input into the gas distribution chamber 25 through the normal-temperature nitrogen source 27, and after being heated by the electric heater 24, it is transported into the environmental simulation chamber 23, so as to create a target environmental temperature around the tested gas cylinder 22;

[0065] S4. Start the pre-stage oil pump 14 and the high-pressure oil pump 16 to carry out the fatigue test of the gas cylinder, which specifically includes the gas cylinder pressure increase stage, the gas cylinder high-pressure pressure holding stage, the gas cylinder pressure decrease stage, and the gas cylinder low-pressure pressure holding stage:

[0066] In the gas cylinder pressure increase stage, the hydraulic oil in the oil tank 1 flows through the pre-stage oil pump 14, the high-pressure oil pump 16 and the one-way valve 17 into the tested gas cylinder 22 to increase the pressure of the gas cylinder;

[0067] In the gas cylinder high-pressure pressure holding stage, the third pneumatic valve 6 is opened, and the hydraulic oil circulates along the oil tank circulation loop composed of the oil tank 1, the high-pressure oil pump 16 and the third pneumatic valve 6, while the high-pressure hydraulic oil in the tested gas cylinder 22 is blocked by the one-way valve 17 to maintain the high pressure in the tested gas cylinder 22;

[0068] In the gas cylinder pressure decrease stage, the first pneumatic valve 4 is opened, and the pressure in the tested gas cylinder 22 is released into the oil tank 1 through the first pneumatic valve 4;

[0069] In the gas cylinder low-pressure pressure holding stage, the first pneumatic valve 4 is closed, and the hydraulic oil still circulates along the oil tank circulation loop composed of the oil tank 1, the high-pressure oil pump 16 and the third pneumatic valve 6.

[0070] The prior art conducts fatigue tests on gas cylinders under normal temperature conditions. However, in the actual use process of gas cylinders, it cannot be fully guaranteed that they are always in a normal temperature environment. The change of environmental temperature will affect the properties of the gas cylinder body material, thereby changing the life of the gas cylinder. Therefore, it is not enough to conduct fatigue tests only at normal temperature, and it is necessary to increase the fatigue tests under the extreme environmental temperatures that may occur during the use of gas cylinders. The present invention provides a test system and method capable of carrying out fatigue tests on gas cylinders in an environment of -70°C to 100°C, which can carry out fatigue tests on gas cylinders in a more demanding environment and obtain test results with higher safety.

[0071] It should be noted that, in this document, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, such that a process, apparatus, article or method comprising a series of elements not only includes those elements but also other elements not expressly listed, or further includes elements inherent to such process, apparatus, article or method. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, apparatus, article or method comprising such element.

[0072] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be similarly included in the patent protection scope of the present invention.

Claims

1. A gas cylinder fatigue test system with variable ambient temperature, characterized in that: It comprises a gas cylinder testing device and a pressure regulating device, wherein the pressure regulating device is connected to the gas cylinder testing device; The gas cylinder testing device comprises a test gas cylinder, an environmental simulation cabin, an electric heater, a gas distribution chamber, a normal temperature nitrogen source, and a liquid nitrogen storage tank. The test gas cylinder is arranged in the environmental simulation cabin and connected to the pressure adjustment device. The environmental simulation cabin is connected to the electric heater, and the electric heater is connected to the gas distribution chamber. The gas distribution chamber is respectively connected to the normal temperature nitrogen source and the liquid nitrogen storage tank. When fatigue testing is required in an environment below ambient temperature, the liquid nitrogen in the liquid nitrogen storage tank enters the gas distribution chamber and is mixed with the normal temperature nitrogen from the normal temperature nitrogen source. After reaching the target temperature, the low temperature nitrogen in the gas distribution chamber enters the environmental simulation cabin, thereby creating a target ambient temperature around the test gas cylinder; When fatigue testing is required in an environment higher than the ambient temperature, gas is input into the gas distribution chamber only through the normal temperature nitrogen source, and after being heated by the electric heater, it is transported to the environmental simulation cabin, thereby creating a target ambient temperature around the test gas cylinder.

2. The variable ambient temperature gas cylinder fatigue testing system according to claim 1, characterized in that: An electric regulating valve is provided between the liquid nitrogen storage tank and the gas distribution chamber, and a portion of the pipeline of the electric regulating valve close to the gas distribution chamber is inserted into the gas distribution chamber, and the inserted pipeline portion serves as a spray pipeline, and a hole is opened at the bottom of the spray pipeline so that the liquid nitrogen in the liquid nitrogen storage tank enters the gas distribution chamber in a spraying manner; The electric regulating valve also adjusts the flow rate of liquid nitrogen entering the gas distribution chamber by adjusting its own opening, thereby adjusting the gas temperature in the gas distribution chamber.

3. The variable ambient temperature gas cylinder fatigue testing system according to claim 2, characterized in that: A seventh manual stop valve is also provided between the room temperature nitrogen source and the gas distribution chamber, and a sixth manual stop valve and a safety valve are sequentially connected between the test gas cylinder and the pressure regulating device.

4. The variable ambient temperature gas cylinder fatigue testing system according to claim 3, characterized in that: The pressure regulating device comprises an oil tank, a front oil pump, a high-pressure oil pump, a one-way valve, a third pneumatic valve, and a first pneumatic valve. The oil tank is respectively connected to the front oil pump, one end of the first pneumatic valve, and one end of the third pneumatic valve. The front oil pump is connected to the inlet end of the high-pressure oil pump. The outlet end of the high-pressure oil pump converges with the other end of the third pneumatic valve and is connected to one end of the one-way valve. The other end of the first pneumatic valve converges with the other end of the one-way valve and is connected to the safety valve. During the cylinder pressure-raising stage, the hydraulic oil in the oil tank flows through the front oil pump, the high-pressure oil pump and the one-way valve into the tested cylinder to raise the pressure of the cylinder; During the high-pressure pressure-maintaining stage of the gas cylinder, the third pneumatic valve is opened, and the hydraulic oil circulates along the oil tank circulation loop composed of the oil tank, the high-pressure oil pump, and the third pneumatic valve, while the high-pressure hydraulic oil in the tested gas cylinder is cut off by the one-way valve to maintain the high pressure in the tested gas cylinder; During the depressurization stage of the gas cylinder, the first pneumatic valve is opened, and the pressure in the tested gas cylinder is released into the oil tank through the first pneumatic valve; During the low-pressure maintenance stage of the gas cylinder, the first pneumatic valve is closed, and the hydraulic oil still circulates along the oil tank circulation loop composed of the oil tank, the high-pressure oil pump, and the third pneumatic valve.

5. The variable ambient temperature gas cylinder fatigue testing system according to claim 4, characterized in that: The oil tank is also provided with an oil tank inlet valve, an oil cooler is provided between the oil tank and the first pneumatic valve and the third pneumatic valve, an electromagnetic valve is provided between the oil tank and the front oil pump, a filter is provided between the front oil pump and the high-pressure oil pump, and the high-pressure oil pump is also connected to a high-pressure oil pump cooler.

6. The variable ambient temperature gas cylinder fatigue testing system according to claim 5, characterized in that: A fourth manual stop valve is arranged between the third pneumatic valve and the one-way valve, a second manual stop valve is arranged between the first pneumatic valve and the one-way valve, and the first manual stop valve is connected in parallel to one end of the first pneumatic valve that is away from the second manual stop valve and the second manual stop valve.

7. The variable ambient temperature gas cylinder fatigue testing system according to claim 6, characterized in that: A second pneumatic valve and a third manual stop valve are connected in parallel to one end of the first pneumatic valve away from the second manual stop valve and one end of the first pneumatic valve in accordance with the principle of the second manual stop valve, the second pneumatic valve serves as a backup valve for the first pneumatic valve, and the third manual stop valve serves as a backup valve for the second manual stop valve; One end of the third pneumatic valve away from the fourth manual stop valve is connected to the principle of the fourth manual stop valve. One end of the third pneumatic valve is connected in parallel with a fourth pneumatic valve and a fifth manual stop valve. The fourth pneumatic valve serves as a backup valve for the third pneumatic valve, and the fifth manual stop valve serves as a backup valve for the fourth manual stop valve.

8. The variable ambient temperature gas cylinder fatigue testing system according to claim 7, characterized in that: An explosion-proof facility for preventing the gas cylinder from rupturing during fatigue testing is provided between the one-way valve and the sixth manual stop valve, so that the explosion-proof facility exists between the pressure regulating device and the gas cylinder testing device.

9. A method for testing fatigue of gas cylinders under variable ambient temperature, characterized in that: The variable ambient temperature gas cylinder fatigue testing system according to claim 8 comprises: S1. Except for the seventh manual stop valve and the spare valve, all manual stop valves in the system are in the open state; S2. First, connect the test gas cylinder to the system, open the seventh manual stop valve to replace the gas distribution chamber and the environmental simulation cabin with nitrogen; S3. After nitrogen replacement is completed, the environmental simulation cabin is configured to the target ambient temperature; specifically comprising: When fatigue testing is required in an environment below ambient temperature, the liquid nitrogen in the liquid nitrogen storage tank enters the gas distribution chamber and is mixed with the normal temperature nitrogen from the normal temperature nitrogen source. After reaching the target temperature, the low temperature nitrogen in the gas distribution chamber enters the environmental simulation cabin, thereby creating a target ambient temperature around the test gas cylinder; When fatigue testing is required in an environment with a temperature higher than the ambient temperature, gas is input into the gas distribution chamber only through the normal temperature nitrogen source, and after being heated by the electric heater, it is transported to the environmental simulation chamber, thereby creating a target ambient temperature around the test gas cylinder; S4, start the front oil pump and the high-pressure oil pump, and perform a fatigue test on the gas cylinder, which specifically includes a gas cylinder pressure-increasing stage, a gas cylinder high-pressure pressure-maintaining stage, a gas cylinder pressure-reducing stage, and a gas cylinder low-pressure pressure-maintaining stage: During the cylinder pressure-raising stage, the hydraulic oil in the oil tank flows through the front oil pump, the high-pressure oil pump and the one-way valve into the tested cylinder to raise the pressure of the cylinder; During the high-pressure pressure-maintaining stage of the gas cylinder, the third pneumatic valve is opened, and the hydraulic oil circulates along the oil tank circulation loop composed of the oil tank, the high-pressure oil pump, and the third pneumatic valve, while the high-pressure hydraulic oil in the tested gas cylinder is cut off by the one-way valve to maintain the high pressure in the tested gas cylinder; During the depressurization stage of the gas cylinder, the first pneumatic valve is opened, and the pressure in the tested gas cylinder is released into the oil tank through the first pneumatic valve; During the low-pressure maintenance stage of the gas cylinder, the first pneumatic valve is closed, and the hydraulic oil still circulates along the oil tank circulation loop composed of the oil tank, the high-pressure oil pump, and the third pneumatic valve.

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