A low-temperature high-pressure valve alternating load impact test system and method

Abstract

The application discloses a low-temperature high-pressure valve alternating load impact test system and method, and belongs to the technical field of pressure test equipment, which comprises a double-cylinder reciprocating liquid pump, an accumulator, a test valve, a regulating valve and the like structures, the double-cylinder reciprocating liquid pump can generate different alternating load impacts through flow path regulation, and the alternating load impacts can be retained or eliminated by whether the accumulator is connected to the flow path or not; one end of the test valve is connected to the reciprocating liquid pump, and the other end is connected to a pressure holding control valve. The application utilizes the pulsating flow and pressure generated by the reciprocating liquid pump to carry out the alternating load impact test of the low-temperature high-pressure valve, and realizes the performance detection and verification of the valve after the impact through the cooperative control of the valve, the pump and the accumulator.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pressure testing equipment, in particular to a low-temperature high-pressure valve alternating load impact test system and method based on a reciprocating liquid pump. BACKGROUND

[0002] Low-temperature high-pressure valves are key equipment in the LNG industry chain and are essential core components of LNG transport ships, LNG receiving stations and liquefaction plants. They work in a low-temperature, high-pressure and large pressure difference environment, requiring leak-proof, corrosion-resistant, anti-cavitation and cold brittle properties, and meeting the requirements of high sealing performance and safety and reliability under-196℃ ultra-low temperature conditions.

[0003] The working environment of low-temperature high-pressure valves is harsh, and they need to ensure safe and stable operation and precise control of valve flow under high pressure difference and alternating load impact. The instantaneous impact faced by the valve during start and stop may also cause failure of the key structure in the valve body, leading to leakage or control failure. Low-temperature high-pressure valves have the characteristics of high cost and difficult maintenance, so they need to be tested and tested for high-pressure alternating load impact before leaving the factory to ensure their stability and safety under extreme conditions.

[0004] The prior art does not have a valve testing system or method suitable for low-temperature high-pressure valves. For example, the Chinese patent document with publication number CN112484986A discloses a valve testing system that simulates different working conditions to improve testing efficiency and can test the valve at the moment of opening.

[0005] For example, the Chinese patent document with publication number CN112903280A discloses a valve impact performance test pipeline and system. The mechanical system is used to provide gas medium and working condition for the test piece, and the measurement and control system is used to control the gas medium and working condition, and also to automatically collect and store test parameters. The mechanical system includes a gas pressurizing unit, a high-pressure gas cylinder unit, a pressure reducing valve mounting unit, a gas cushion simulation unit and a flow regulating unit; the gas pressurizing unit is used to pressurize the gas medium; the high-pressure gas cylinder unit is used to store and release the gas medium; the pressure reducing valve mounting unit is used to clamp and fix the test valve; the gas cushion simulation unit is used to simulate the volume change of the pipeline behind the test valve; and the flow simulation unit is used to simulate the working condition when the valve flow is different.

[0006] Therefore, there is an urgent need to design a low-temperature high-pressure valve testing system that can provide high pressure difference and alternating load impact. SUMMARY

[0007] The application provides a low-temperature high-pressure valve alternating load impact test system, which can impact the valve multiple times by using the pulsating flow and pressure generated by a reciprocating liquid pump, test the sealing performance of the reciprocating liquid pump by pressurization detection after the impact is completed, and verify the precise control ability of the valve under long-term impact by comparing the flow characteristic curves before and after the impact.

[0008] The low-temperature high-pressure valve alternating load impact test system comprises a liquid storage tank, a circulating tank and a double-cylinder reciprocating liquid pump.

[0009] The outlet of the liquid storage tank is connected with the circulating tank, the outlet of the circulating tank is divided into two paths after passing through a total valve, one path is connected with the first interface of a No. 1 three-way valve, and the other path is connected with the lower working cavity inlet of the double-cylinder reciprocating liquid pump through a lower inlet check valve, the lower working cavity outlet is connected with the third interface of a No. 2 three-way valve through a lower outlet check valve, and the first interface of the No. 2 three-way valve is connected with the circulating tank.

[0010] The third interface of the No. 1 three-way valve is connected with the upper working cavity inlet of the double-cylinder reciprocating liquid pump through an upper inlet check valve, the upper working cavity outlet is connected with the second interface of the No. 2 three-way valve after passing through an upper outlet check valve, the pipeline after the combination is sequentially connected with a safety valve, a back pressure valve, a pre-valve pressure gauge, a test valve, a post-valve pressure gauge, the first and second interfaces of a No. 3 three-way valve, a pressure holding control valve and a flowmeter and then returns to the circulating tank, the third interface of the No. 3 three-way valve is connected with the second interface of the No. 1 three-way valve, and the first and second accumulator control valves are respectively connected with a first accumulator and a second accumulator on the pipeline between the safety valve and the back pressure valve.

[0011] The pre-valve pressure gauge, the post-valve pressure gauge and the flowmeter are connected with a display instrument, the display instrument monitors the real-time data of the pre-valve pressure gauge, the post-valve pressure gauge and the flowmeter and transmits the data to a control platform.

[0012] The application uses the pulsating flow and pressure generated by the double-cylinder reciprocating liquid pump to carry out the alternating load impact test of the low-temperature high-pressure valve, and realizes the performance detection and verification of the valve after the impact through the cooperative control of the valve, the pump and the accumulator.

[0013] Alternatively, the double-cylinder reciprocating liquid pump is a double-cylinder double-acting piston pump, a double-cylinder double-acting plunger pump or a double-cylinder double-acting diaphragm pump.

[0014] Alternatively, the test valve can be a butterfly valve, a ball valve, a gate valve, a stop valve or a check valve.

[0015] Alternatively, the circulating working medium can be but is not limited to a low-temperature liquid.

[0016] The application further provides a low-temperature high-pressure valve alternating load impact test method.

[0017] Specifically, in the continuous half-sine impact, the first interface and the third interface of the first three-way valve are controlled to be opened, and the second interface is controlled to be closed; the second interface and the third interface of the second three-way valve are controlled to be opened, and the first interface is controlled to be closed; the first interface and the second interface of the third three-way valve are controlled to be opened, and the third interface is controlled to be closed; the first accumulator control valve and the second accumulator control valve are both controlled to be closed; and the test valve and the pressure holding control valve are controlled to be opened.

[0018] In the interval half-sine impact, the first interface and the third interface of the first three-way valve are controlled to be opened, and the second interface is controlled to be closed; the first interface and the third interface of the second three-way valve are controlled to be opened, and the second interface is controlled to be closed; the first interface and the second interface of the third three-way valve are controlled to be opened, and the third interface is controlled to be closed; the first accumulator control valve and the second accumulator control valve are both controlled to be closed; and the test valve and the pressure holding control valve are controlled to be opened.

[0019] In the continuous sine impact, the second interface and the third interface of the first three-way valve are controlled to be opened, and the first interface is controlled to be closed; the first interface and the third interface of the second three-way valve are controlled to be opened, and the second interface is controlled to be closed; the first interface and the third interface of the third three-way valve are controlled to be opened, and the second interface is controlled to be closed; the first accumulator control valve is controlled to be opened, and the second accumulator control valve is controlled to be closed; and the test valve and the pressure holding control valve are controlled to be opened.

[0020] After the alternating load impact is performed, the sealing performance and the control performance of the test valve are tested, the first interface and the third interface of the first three-way valve are controlled to be opened, and the second interface is controlled to be closed; the second interface and the third interface of the second three-way valve are controlled to be opened, and the first interface is controlled to be closed; the first interface and the second interface of the third three-way valve are controlled to be opened, and the third interface is controlled to be closed; and the specific test process includes the following three stages.

[0021] In the valve leakage detection stage, the first accumulator control valve, the second accumulator control valve and the pressure holding control valve are closed, and the test valve is opened; the double-cylinder reciprocating liquid pump pumps the pressurized liquid into the test valve until the design pressure of the test valve stops; based on the pressurized detection leakage method, whether the test valve has leakage is judged by observing the change of the pressure gauges before and after the valve.

[0022] In the valve internal leakage detection stage, the first accumulator control valve, the second accumulator control valve and the test valve are closed, and the pressure control valve is opened; the double-cylinder reciprocating liquid pump pumps the pressurized to the pipeline in front of the test valve until the design pressure of the test valve stops; based on the pressurized detection leakage method, by observing the change of the pressure gauge in front of the valve, if no external leakage phenomenon is found in the valve external leakage detection stage, it can be judged whether the test valve appears internal leakage phenomenon;

[0023] In the valve control accuracy detection stage, the first accumulator control valve, the second accumulator control valve, the pressure control valve and the test valve are opened; the double-cylinder reciprocating liquid pump pumps the pressurized to the test valve, the pulsating pressure and flow are stabilized by the first accumulator and the second accumulator and then enter the test valve with a certain opening, and then return to the circulating tank through the No. 3 three-way valve, the pressure control valve and the flowmeter; by measuring the pressure difference before and after the test valve at different openings, the flow characteristics of the test valve after the alternating load impact are obtained, and whether the valve control accuracy is affected by the alternating load impact is determined by comparison.

[0024] Compared with the prior art, the present application has the following beneficial effects:

[0025] 1、The low-temperature high-pressure valve alternating load impact test system provided by the present application uses a reciprocating liquid pump as a pulsating pressure source, can realize a large range of pressure fluctuation up to 100MPa, and can meet the test demand of extreme working conditions. At the same time, the test system provided by the present application can also realize stable flow and pressure output of the reciprocating liquid pump by connecting an accumulator, so as to meet the sealing performance and control performance demand of the test valve after the alternating load impact test.

[0026] 2、The present application uses the pulsating flow and pressure generated by the reciprocating liquid pump to impact the valve for multiple times, tests the sealing performance of the reciprocating liquid pump by the pressurized detection method after the impact ends, and can verify the accurate control ability of the valve under long-term impact by comparing the flow characteristic curves before and after the impact. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is a whole structure schematic view of the low-temperature high-pressure valve alternating load impact test system of the present application;

[0028] Figure 2 It is a pipeline connection schematic view when the present application carries out continuous half-sine impact;

[0029] Figure 3 It is a pipeline connection schematic view when the present application carries out interval half-sine impact;

[0030] Figure 4 It is a pipeline connection schematic view when the present application carries out continuous sine impact;

[0031] Figure 5A schematic diagram of pipeline communication for testing the sealing and regulating performance of the regulating valve in the present application;

[0032] Figure 6 Output characteristic curve of the reciprocating liquid pump when continuous half-sine impact is performed;

[0033] Figure 7 Output characteristic curve of the reciprocating liquid pump when interval half-sine impact is performed;

[0034] Figure 8 Output characteristic curve of the reciprocating liquid pump when continuous sine impact is performed. DETAILED DESCRIPTION

[0035] The present application will be further described in detail below in conjunction with the accompanying drawings and examples, it should be noted that the following examples are intended to facilitate the understanding of the present application and do not limit the present application in any way.

[0036] As shown in the drawings, Figure 1 A low-temperature high-pressure valve alternating load impact test system, comprising a liquid storage tank 1, a circulating tank 4 and a double-cylinder reciprocating liquid pump 10.

[0037] The outlet of the liquid storage tank 1 is connected with the circulating tank 4 through a pipeline with a regulating valve 2, and a liquid storage tank pressure gauge 3 is arranged on the pipeline; the outlet of the circulating tank 4 is divided into two routes after passing through a total valve 5, one of which is connected with the first interface of a No. 1 three-way valve 6, and the other is connected with the lower working chamber inlet of the double-cylinder reciprocating liquid pump 10 through a lower inlet check valve 9, the lower working chamber outlet is connected with the third interface of a No. 2 three-way valve 13 through a lower outlet check valve 12, and the first interface of the No. 2 three-way valve 13 is connected with the circulating tank 4. The piston of the double-cylinder reciprocating liquid pump 10 is driven by a motor 11.

[0038] The third interface of the No. 1 three-way valve 6 is connected with the upper working chamber inlet of the double-cylinder reciprocating liquid pump 10 through an upper inlet check valve 7, the upper working chamber outlet is connected with the second interface of the No. 2 three-way valve 13 after passing through an upper outlet check valve 8, the pipeline after the confluence is sequentially connected with a safety valve 14, a back pressure valve 19, a pre-valve pressure gauge 20, a test valve 21, a post-valve pressure gauge 22, the first and second interfaces of a No. 3 three-way valve 23, a pressure holding control valve 24 and a flowmeter 25, and then returns to the circulating tank 4, and the third interface of the No. 3 three-way valve 23 is connected with the second interface of the No. 1 three-way valve 6; the pipeline between the safety valve 14 and the back pressure valve 19 is connected with a first energy accumulator 16 and a second energy accumulator 18 through a first energy accumulator control valve 15 and a second energy accumulator control valve 17, respectively.

[0039] The valve front pressure gauge 20, the valve rear pressure gauge 22 and the flow meter 25 are connected with a display instrument 26, the display instrument 26 is used for monitoring real-time data of the valve front pressure gauge 20, the valve rear pressure gauge 22 and the flow meter 25, and is transmitted to a control platform 27. The control platform 27 is responsible for the state control of the double-cylinder reciprocating liquid pump 10 and each valve.

[0040] In the present application, the double-cylinder reciprocating liquid pump 10 is used to deliver liquid to the test valve 21, and the flow fluctuation and pressure fluctuation generated by the double-cylinder reciprocating liquid pump 10 are directly transmitted to the flow control components such as the valve rod and valve disc of the test valve 21 through the pipeline (the pre-accumulator valve is closed) (the valves such as butterfly valves and ball valves for adjusting or cutting off need to maintain a certain opening degree in the alternating load impact test) to realize the simulation of the alternating load impact environment in front of the valve. After the test valve needs to bear the flow and pressure fluctuation times, the control valve behind the closed test valve 21 is closed, and the liquid pressure in the test valve 21 is raised to the required test pressure by the double-cylinder reciprocating liquid pump 10. Based on the pressurization detection method, when the test valve 21 is not closed, the external leakage of the valve can be checked according to the pressure gauges before and after the test valve 21; when the test valve 21 is closed, the control valve behind the opened test valve 21 can be opened, and the internal leakage of the valve can be checked according to the pressure gauge before the test valve 21. After the pre-accumulator valve is opened, the reciprocating liquid pump can output stable flow and pressure to the test valve together with the accumulator at this time, and the flow characteristic curve of the valve can be measured, and the standard characteristic curve of the test valve is compared to evaluate the control accuracy of the valve after bearing the alternating load impact.

[0041] In the specific implementation process, the double-cylinder reciprocating liquid pump 10 can adopt a double-cylinder double-acting piston pump, a double-cylinder double-acting plunger pump or a double-cylinder double-acting diaphragm pump.

[0042] The double-cylinder double-acting piston pump includes a compression cylinder, an inlet valve, an outlet valve and a piston, relies on the reciprocating motion of the piston to periodically change the volume of the pump cavity, and realizes the pressurized delivery of the liquid. The double-cylinder double-acting plunger pump includes a compression cylinder, an inlet valve, an outlet valve and a plunger, relies on the reciprocating motion of the plunger to periodically change the volume of the pump cavity, and realizes the pressurized delivery of the liquid. The double-cylinder double-acting diaphragm pump includes a compression cylinder, an inlet valve, an outlet valve, a piston, hydraulic oil and a diaphragm, and realizes the pressurized delivery of the liquid by transmitting the pressure from the piston to the diaphragm and then to the liquid to be pressed.

[0043] The test valve 21 can be a butterfly valve, a ball valve, a gate valve, a stop valve or a check valve. The butterfly valve includes a valve disc, a valve shaft, a valve cover, a valve body and a valve seat; the ball valve includes a ball, a valve shaft, a valve cover, a valve body and a valve seat; the gate valve includes a gate plate, a valve shaft, a valve cover, a valve body and a valve seat; the stop valve includes a valve disc, a valve shaft, a valve cover, a valve body and a valve seat; and the check valve includes a valve disc, a valve shaft, a valve cover, a valve body and a valve seat.

[0044] The working fluid used in the circulation of the whole test system can be, but is not limited to, low-temperature liquid.

[0045] When the above system is used for the alternating load impact test, the first three-way valve 6, the second three-way valve 13, the third three-way valve 23, the first accumulator control valve 15 and the second accumulator control valve 17 are adjusted to make the impact on the test valve 21 have three modes of continuous half-sine impact, interval half-sine impact and continuous sine impact.

[0046] As shown in Figure 2 , the pipeline connection state when the continuous half-sine impact test is performed, at this time, the output characteristic curve of the reciprocating liquid pump is as shown in Figure 6 .

[0047] The specific pipeline connection state is that the first interface and the third interface of the first three-way valve 6 are opened, and the second interface is closed; the second interface and the third interface of the second three-way valve 13 are opened, and the first interface is closed; the first interface and the second interface of the third three-way valve 23 are opened, and the third interface is closed; the first accumulator control valve 15 and the second accumulator control valve 17 are both closed; the test valve 21 and the pressure holding control valve 24 are opened.

[0048] The liquid in the circulation tank 4 enters the two-stage compression cylinders of the double-cylinder reciprocating liquid pump 10 driven by the motor 11 through the total valve 5, the first three-way valve 6, the inlet check valve 7, and the inlet check valve 9, is pressurized, and then flows out through the outlet check valve 8, the outlet check valve 12, the second three-way valve 13, and the back pressure valve 19 to continuously impact the test valve 21. The pressure threshold of the safety valve 14 is set according to the design parameters of the test valve 21 to prevent the pressure from being too high. The high-pressure liquid after impact flows back to the circulation tank 4 through the third three-way valve 23 and the pressure holding control valve 24.

[0049] As shown in Figure 3 , the pipeline connection state when the interval half-sine impact test is performed, at this time, the output characteristic curve of the reciprocating liquid pump is as shown in Figure 7 .

[0050] The specific pipeline connection state is that the first interface and the third interface of the first three-way valve 6 are opened, and the second interface is closed; the first interface and the third interface of the second three-way valve 13 are opened, and the second interface is closed; the first interface and the second interface of the third three-way valve 23 are opened, and the third interface is closed; the first accumulator control valve 15 and the second accumulator control valve 17 are both closed; the test valve 21 and the pressure holding control valve 24 are opened.

[0051] The liquid in the circulation tank 4 flows through the total valve 5, and part of the liquid flows through the inlet check valve 9 into one compression cylinder of the double-cylinder reciprocating liquid pump 10 driven by the motor 11, and after being pressurized, the liquid flows back to the circulation tank 4 through the outlet check valve 12 and the second three-way valve 13. Part of the liquid flows through the first three-way valve 6 and the inlet check valve 7 into the other compression cylinder of the double-cylinder reciprocating liquid pump 10 driven by the motor 11, and after being pressurized, the liquid continuously impacts the test valve 21 through the outlet check valve 8, the back pressure valve 19. The pressure threshold of the safety valve 14 is set according to the design parameters of the test valve 21 to prevent excessive pressure. The high-pressure liquid after impact flows back to the circulation tank 4 through the third three-way valve 23 and the pressure holding control valve 24.

[0052] As shown in Figure 4 , the pipeline connection state when performing continuous sine impact test experiment, at this time, the output characteristic curve of the reciprocating liquid pump is as shown in Figure 8 .

[0053] The specific pipeline connection state is: the second interface and the third interface of the first three-way valve 6 are opened, and the first interface is closed; the first interface and the third interface of the second three-way valve 13 are opened, and the second interface is closed; the first interface and the third interface of the third three-way valve 23 are opened, and the second interface is closed; the first accumulator control valve 15 is opened, and the second accumulator control valve 17 is closed; the test valve 21 and the pressure holding control valve 24 are opened.

[0054] The liquid in the circulation tank 4 flows through the total valve 5, the inlet check valve 9, and into one compression cylinder of the double-cylinder double-acting reciprocating liquid pump 10 driven by the motor 11, and then flows back to the circulation tank 4 through the outlet check valve 12 and the second three-way valve 13. In the other closed circulation, the liquid is pressurized by the other compression cylinder of the double-cylinder reciprocating liquid pump 10, and after being pressurized, the liquid continuously impacts the test valve 21 through the outlet check valve 8, the first accumulator control valve 15, the first accumulator 16, and the back pressure valve 19. The pressure threshold of the safety valve 14 is set according to the design parameters of the test valve 21 to prevent excessive pressure. The high-pressure liquid after impact flows back to the double-cylinder reciprocating liquid pump 10 through the third three-way valve 23 and the first three-way valve 6.

[0055] After the above-mentioned three alternating load impact stages of continuous half-sine impact, interval half-sine impact, and continuous sine impact, the present embodiment performs a test on the sealing performance and control performance of the regulating valve, and the pipeline connection state at this time is as shown in Figure 5 .

[0056] The liquid from the liquid storage tank 1 flows into the circulation tank 4 through the regulating valve 2, which is used to maintain the liquid level in the circulation tank, and the following stages are performed in sequence: valve external leakage detection stage, valve internal leakage detection stage, and valve control accuracy detection stage.

[0057] In the valve leakage detection stage, the first accumulator control valve 15, the second accumulator control valve 17 and the pressure holding control valve 24 are closed, and the test valve 21 is opened. The double-cylinder reciprocating liquid pump 10 pumps pressurized liquid into the test valve 21 until the design pressure of the test valve 21 stops. Based on the pressurized leakage detection method, by observing the changes of the valve front pressure gauge 20 and the valve rear pressure gauge 22 within a certain period of time, it can be determined whether the test valve 21 has leakage phenomenon.

[0058] In the valve leakage detection stage, the first accumulator control valve 15, the second accumulator control valve 17 and the test valve 21 are closed, one way of the three-way valve 23 connected with the pressure holding control valve 24 is opened, and the pressure holding control valve 24 is opened. The double-cylinder reciprocating liquid pump 10 pumps pressurized liquid into the pipeline in front of the test valve 21 until the design pressure of the test valve 21 stops. Based on the pressurized leakage detection method, by observing the changes of the valve front pressure gauge 20 within a certain period of time, if no leakage phenomenon is found in the valve leakage detection stage, it can be determined whether the test valve 20 has internal leakage phenomenon.

[0059] In the valve control accuracy detection stage, the first accumulator control valve 15, the second accumulator control valve 17, the pressure holding control valve 24 and the test valve 21 are all opened. The double-cylinder reciprocating liquid pump 10 pumps pressurized liquid into the test valve 21, and the pulsating pressure and flow are stabilized by the first accumulator 16 and the second accumulator 18 before entering the test valve 21 with a certain opening degree, and then return to the circulating tank 4 through the three-way valve 23, the pressure holding control valve 24 and the flowmeter 25. By measuring the pressure difference before and after the test valve 21 at different openings, the flow characteristics of the test valve after the alternating load impact can be obtained, and by comparison, it can be determined whether the valve control accuracy is affected by the alternating load impact.

[0060] During the experiment, the display instrument 26 monitors the real-time data of the valve front pressure gauge 20, the valve rear pressure gauge 22 and the flowmeter 25, and transmits them to the control platform 27. Based on the data transmitted by the display instrument and the test task, the control platform adjusts the operating frequency of the motor 11, controls the opening and closing of the first accumulator control valve 15, the second accumulator control valve 17 and the pressure holding control valve 24, and the opening of the test valve 21.

[0061] The above embodiments have described the technical solutions and beneficial effects of the present application in detail. It should be understood that the above description is only a specific embodiment of the present application and is not intended to limit the present application. Any modification, supplement and equivalent replacement made within the principle range of the present application shall be included in the protection scope of the present application.

Claims

1. A low temperature high pressure valve alternating load shock test system, characterized by, It comprises a liquid storage tank (1), a circulating tank (4) and a double-cylinder reciprocating liquid pump (10). The outlet of the liquid storage tank (1) is connected with the circulating tank (4), the outlet of the circulating tank (4) is divided into two ways after passing through a total valve (5), one of the two ways is connected with the first interface of a No. 1 three-way valve (6), the other way is connected with the lower working chamber inlet of the double-cylinder reciprocating liquid pump (10) through a lower inlet check valve (9), the outlet of the lower working chamber is connected with the third interface of a No. 2 three-way valve (13) through a lower outlet check valve (12), the first interface of the No. 2 three-way valve (13) is connected with the circulating tank (4); The third interface of the No. 1 three-way valve (6) is connected with the upper working chamber inlet of the double-cylinder reciprocating liquid pump (10) through an upper inlet check valve (7), the outlet of the upper working chamber is connected with the second interface of the No. 2 three-way valve (13) after passing through an upper outlet check valve (8), the pipeline after the combination is sequentially returned to the circulating tank (4) after passing through a safety valve (14), a back pressure valve (19), a pre-valve pressure gauge (20), a test valve (21), a post-valve pressure gauge (22), the first and second interfaces of a No. 3 three-way valve (23), a pressure holding control valve (24) and a flowmeter (25), the third interface of the No. 3 three-way valve (23) is connected with the second interface of the No. 1 three-way valve (6); the first and second accumulator control valves (15, 17) are respectively connected with a first accumulator (16) and a second accumulator (18) through the pipeline between the safety valve (14) and the back pressure valve (19); The pre-valve pressure gauge (20), the post-valve pressure gauge (22) and the flowmeter (25) are connected with a display instrument (26), the display instrument (26) monitors the real-time data of the pre-valve pressure gauge (20), the post-valve pressure gauge (22) and the flowmeter (25) and transmits them to a control platform (27).

2. The cryogenic high pressure valve alternating load shock test system of claim 1, wherein, The double-cylinder reciprocating liquid pump (10) is a double-cylinder double-acting piston pump, a double-cylinder double-acting plunger pump or a double-cylinder double-acting diaphragm pump.

3. The cryogenic high pressure valve alternating load shock test system of claim 1, wherein, The test valve (21) is a butterfly valve, a ball valve, a gate valve, a stop valve or a check valve.

4. A method of low temperature high pressure valve alternating load shock testing, the method comprising: The low-temperature high-pressure valve alternating load impact test system of any one of claims 1-3 is used to impact the test valve (21) in a continuous half-sine impact, an interval half-sine impact and a continuous sine impact by adjusting the No. 1 three-way valve (6), the No. 2 three-way valve (13), the No. 3 three-way valve (23), the first accumulator control valve (15) and the second accumulator control valve (17).

5. The cryogenic high pressure valve alternating load shock test method of claim 4, wherein, In the continuous half-sine impact, the first and third interfaces of the No. 1 three-way valve (6) are opened, the second interface is closed; the second and third interfaces of the No. 2 three-way valve (13) are opened, the first interface is closed; the first and second interfaces of the No. 3 three-way valve (23) are opened, the third interface is closed; the first and second accumulator control valves (15, 17) are closed; the test valve (21) and the pressure holding control valve (24) are opened.

6. The cryogenic high pressure valve alternate load shock test method of claim 4, wherein, When the interval half-sine shock is performed, the first port and the third port of the first three-way valve (6) are opened, the second port is closed; the first port and the third port of the second three-way valve (13) are opened, the second port is closed; the first port and the second port of the third three-way valve (23) are opened, the third port is closed; the first accumulator control valve (15) and the second accumulator control valve (17) are closed; the test valve (21) and the pressure holding control valve (24) are opened.

7. The cryogenic high pressure valve alternate load shock test method of claim 4, wherein, When the continuous sine shock is performed, the second port and the third port of the first three-way valve (6) are opened, the first port is closed; the first port and the third port of the second three-way valve (13) are opened, the second port is closed; the first port and the third port of the third three-way valve (23) are opened, the second port is closed; the first accumulator control valve (15) is opened, the second accumulator control valve (17) is closed; the test valve (21) and the pressure holding control valve (24) are opened.

8. The cryogenic high pressure valve alternate load shock test method of claim 4, wherein, After the alternating load shock is performed, the sealing performance and the control performance of the test valve (21) are tested, the first port and the third port of the first three-way valve (6) are opened, the second port is closed; the second port and the third port of the second three-way valve (13) are opened, the first port is closed; the first port and the second port of the third three-way valve (13) are opened, the third port is closed; the specific test process includes the following three stages: In the valve external leakage detection stage, the first accumulator control valve (15), the second accumulator control valve (17) and the pressure holding control valve (24) are closed, and the test valve (21) is opened; the double-cylinder reciprocating liquid pump (10) pumps pressure to the test valve (21) until the design pressure of the test valve (21) stops; based on the pressure detection leakage method, by observing the changes of the valve front pressure gauge (20) and the valve rear pressure gauge (22), it is judged whether the test valve (21) has external leakage phenomenon; In the valve internal leakage detection stage, the first accumulator control valve (15), the second accumulator control valve (17) and the test valve (21) are closed, and the pressure holding control valve (24) is opened; the double-cylinder reciprocating liquid pump (10) pumps pressure to the pipeline before the test valve (21) until the design pressure of the test valve (21) stops; based on the pressure detection leakage method, by observing the changes of the valve front pressure gauge (20), if no external leakage phenomenon is found in the valve external leakage detection stage, it can be judged whether the test valve (21) has internal leakage phenomenon; In the valve control accuracy detection stage, the first accumulator control valve (15), the second accumulator control valve (17), the pressure holding control valve (24) and the test valve (21) are all opened; the double-cylinder reciprocating liquid pump (10) pumps the pressurized liquid to the test valve (21), the pulsating pressure and flow are stabilized by the first accumulator (16) and the second accumulator (18) and then enter the test valve (21) with a certain opening degree, and then return to the circulating tank (4) through the third three-way valve (23), the pressure holding control valve (24) and the flowmeter (25); by measuring the pressure difference before and after the test valve (21) at different openings, the flow characteristics of the test valve (21) after the alternating load impact are obtained, and whether the valve control accuracy is affected by the alternating load impact is determined by comparison.

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