A kind of gas cylinder hydraulic alternating cycle test control device

Abstract

The utility model belongs to cylinder detection technical field, especially relates to a kind of cylinder hydraulic pressure alternating cycle test control device, including water storage tank, exhaust valve, pipeline pressure increasing unit, pressure sensing unit and control execution unit, and pipeline pressure increasing unit includes electric pressure test pump, water inlet pipeline, backwater pipeline;Control execution unit includes PLC controller, host computer, be set between the water inlet pipeline and backwater pipeline and start unloading module, pulse unloading module, pulse loading module;Test loading module is set in the water inlet pipeline;Pressure sensing unit includes the first pressure sensor being set in the water outlet of electric pressure test pump and the second pressure sensor being set in the water inlet of the cylinder to be measured. By using the utility model, high-precision pressure control can be achieved.

Description

Technical Field

[0001] This utility model belongs to the field of gas cylinder testing technology, and in particular relates to a gas cylinder hydraulic alternating cycle test control device. Background Technology

[0002] In modern industry and daily life, gas cylinders play a crucial role, serving as indispensable gas storage and transportation equipment. During actual use, gas cylinders frequently undergo filling, transportation, storage, and usage, resulting in continuous pressure changes within them. For example, the pressure rises rapidly during filling and gradually decreases as gas is released during use. This cyclical pressure variation, much like the pulse of the human body, continuously impacts the structure and performance of the gas cylinder. If a gas cylinder cannot withstand these alternating pressure changes, various safety issues may arise. Therefore, conducting fatigue cycle tests on gas cylinders to simulate the pressure changes they experience during actual use is crucial.

[0003] However, existing gas cylinder fatigue cycle testing devices have significant shortcomings in pressure control accuracy. Existing fatigue cycle testing devices, such as the one in patent application number 201711249924.5, employ a relatively simple pressure control method, controlling pressure changes during the test solely through a pressurization pump unit. During hydraulic alternating cycle testing, the pressure fluctuation range is large, making it difficult to stably maintain it within the specified upper and lower pressure limits. This severely affects the accuracy of the test results, failing to truly reflect the stress conditions experienced by the gas cylinder during actual use. Utility Model Content

[0004] The purpose of this invention is to provide a hydraulic alternating cycle test control device for gas cylinders, which aims to solve the problem of low pressure control accuracy in existing gas cylinder fatigue cycle test devices.

[0005] To achieve the above objectives, this utility model provides a hydraulic alternating cycle test control device for gas cylinders, comprising a water tank, an exhaust valve, a pipeline pressurization unit, a pressure sensing unit, and a control execution unit, wherein: The pipeline pressurization unit includes an electric pressure testing pump, an inlet pipeline, and a return pipeline; The control execution unit includes a PLC controller, a host computer, a start-up unloading module, a pulse unloading module, and a pulse loading module installed between the inlet water pipe and the return water pipe; and a test loading module installed in the inlet water pipe. The pressure sensing unit includes a first pressure sensor disposed at the outlet of the electric pressure testing pump and a second pressure sensor disposed at the inlet of the gas cylinder to be tested. The water storage tank is connected to the inlet of the electric pressure testing pump; the outlet of the electric pressure testing pump is connected to the inlet of the start-up unloading module and the inlet of the test loading module; the outlet of the test loading module is connected to the inlet of the pulse unloading module, the inlet of the pulse loading module, the inlet of the exhaust valve, and the gas cylinder to be tested; the outlets of the start-up unloading module, the pulse unloading module, the pulse loading module, and the exhaust valve are connected to the return water pipeline. The host computer is electrically connected to the PLC controller and is used to transmit user control commands to the PLC controller and generate control signals; the PLC controller is electrically connected to the first pressure sensor, the second pressure sensor, the start-up unloading module, the pulse unloading module, the pulse loading module, and the test loading module.

[0006] As an optional solution of this utility model, the bottom of the water storage tank is provided with a water level sensor and a temperature sensor, which are used to detect the water level and water temperature in the water storage tank, respectively.

[0007] As an optional solution of this utility model, a wind cooler is connected to one side of the water storage tank, and the wind cooler and the water storage tank form a water circulation loop to reduce the water temperature in the water storage tank.

[0008] As an optional solution of this utility model, the start-up unloading module includes a start-up unloading valve and a first one-way valve. The inlet of the start-up unloading valve is connected to the outlet of the electric pressure testing pump; the outlet of the start-up unloading valve is connected to the inlet of the first one-way valve; and the outlet of the first one-way valve is connected to the return water pipeline.

[0009] As an optional embodiment of this utility model, the test loading module includes a test solenoid valve and a second check valve. The inlet of the test solenoid valve is connected to the outlet of the electric test pump; the outlet of the test solenoid valve is connected to the inlet of the second check valve; and the outlet of the second check valve is connected to the inlet of the pulse unloading module.

[0010] As an optional embodiment of this utility model, the pulse unloading module includes a pulse unloading valve and a throttle valve. The inlet of the pulse unloading valve is connected to the outlet of the second one-way valve; the outlet of the pulse unloading valve is connected to the inlet of the throttle valve; and the outlet of the throttle valve is connected to the return water passage.

[0011] As an optional solution of this utility model, the pulse loading module includes a pulse loading valve and a back pressure valve. The inlet of the pulse loading valve is connected to the outlet of the second one-way valve; the outlet of the pulse loading valve is connected to the inlet of the back pressure valve; and the outlet of the back pressure valve is connected to the return water passage.

[0012] As an optional solution of this utility model, a diverter is provided between the gas cylinder and the water inlet pipe.

[0013] As an optional solution of this utility model, an overflow valve is provided at the outlet of the electric pressure testing pump, the inlet of the overflow valve is connected to the outlet of the electric pressure testing pump, and the outlet of the overflow valve is connected to the return water passage.

[0014] As an optional solution of this utility model, the outlet of the electric pressure testing pump is provided with a first shut-off valve and a first pointer pressure gauge, which are used to cut off the water flow at the outlet of the electric pressure testing pump in an emergency; the inlet of the pulse loading valve is provided with a second shut-off valve and a second pointer pressure gauge, which are used to cut off the water flow at the inlet of the pulse loading valve in an emergency.

[0015] The above-mentioned technical solutions in the gas cylinder hydraulic alternating cycle test control device provided in this embodiment of the utility model have at least one of the following technical effects: This application provides a hydraulic alternating cycle test control device for gas cylinders. Equipped with a pressure sensing unit and a control execution unit, it can precisely regulate pressure changes during the test. A first pressure sensor and a second pressure sensor are respectively installed at the outlet of the electric test pump and the inlet of the gas cylinder under test, monitoring water pressure in real time and providing accurate data support for pressure regulation. The PLC controller precisely controls the start-up unloading module, pulse unloading module, pulse loading module, and test loading module based on the pressure signals fed back from the sensors. This ensures that during the test, hydraulic pressure is stably applied to the gas cylinder under test according to the set pressure value and cycle frequency, achieving a stable hydraulic alternating cycle test. This precise pressure control effectively avoids the impact of pressure fluctuations on the test results, ensuring the accuracy and stability of the test, making the test data more reliable, and providing a solid data foundation for gas cylinder quality inspection. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the pipeline of a hydraulic alternating cycle test control device for gas cylinders according to the present invention.

[0018] Figure 2 This is a schematic diagram of the structure of a hydraulic alternating cycle test control device for gas cylinders according to the present invention.

[0019] Figure Descriptions: 1. Control Cabinet; 2. Air-cooled Unit; 3. Frame; 4. Water Tank; 5. Test Gas Cylinder; 6. Sample Cabinet; 7. Electric Test Pump; 701. Filter; 8. Start-up Unloading Module; 801. Start-up Unloading Valve; 802. First Check Valve; 9. Test Loading Module; 901. Test Solenoid Valve; 902. Second Check Valve; 10. Pulse Unloading Module; 1001. Pulse Unloading Valve; 1002. Throttling Valve; 11. Pulse loading module; 1101, pulse loading valve; 1102, back pressure valve; 12, exhaust valve; 13, first shut-off valve; 1301, first pointer pressure gauge; 14, second shut-off valve; 1401, second pointer pressure gauge; 15, water level sensor; 16, temperature sensor; 17, overflow valve; 18, first pressure sensor; 19, second pressure sensor; 20, diverter; 21, return water pipeline; 22, inlet water pipeline. Detailed Implementation

[0020] The embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the embodiments of the present invention, and should not be construed as limiting the present invention.

[0021] In the description of the embodiments of this utility model, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing the embodiments of this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0022] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0023] In this embodiment of the invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this embodiment of the invention according to the specific circumstances.

[0024] In specific embodiments of this utility model, such as Figure 1 As shown, a hydraulic alternating cycle test control device for gas cylinders is provided, comprising a water tank 4, an exhaust valve 12, a pipeline pressurization unit, a pressure sensing unit, and a control execution unit, wherein: The pipeline pressurization unit includes an electric pressure testing pump 7, an inlet water pipeline 22, and a return water pipeline 21; The control execution unit includes a PLC controller, a host computer, a start-up unloading module 8, a pulse unloading module 10, and a pulse loading module 11 installed between the inlet water pipe 22 and the return water pipe 21; and a test loading module 9 installed in the inlet water pipe 22. The pressure sensing unit includes a first pressure sensor 18 installed at the outlet of the electric pressure testing pump 7 and a second pressure sensor 19 installed at the inlet of the gas cylinder 5 to be tested. The water storage tank 4 is connected to the inlet of the electric pressure testing pump 7 through a pipeline to provide the test medium for the hydraulic alternating cycle test of the gas cylinder to the electric pressure testing pump 7. The outlet of the electric pressure testing pump 7 is connected to the inlet of the start-up unloading module 8 and the inlet of the test loading module 9 through the inlet pipe 22. The outlet of the test loading module 9 is connected to the inlet of the pulse unloading module 10, the inlet of the pulse loading module 11, the inlet of the exhaust valve 12, and the gas cylinder 5 to be tested. The outlets of the start-up unloading module 8, the pulse unloading module 10, the pulse loading module 11, and the exhaust valve 12 are connected to the return water pipe 21. The start-up unloading module 8, test loading module 9, pulse unloading module 10 and pulse loading module 11 are connected by pipelines to form a collaborative control logic. The start-up unloading module 8 is responsible for system start-up and shutdown protection, the test loading module 9 is responsible for the overall control of the test circuit on and off, and the pulse unloading module 10 and pulse loading module 11 work alternately and adjust parameters to jointly realize the pressure alternating cycle of the gas cylinder 5 under test.

[0025] The outlet of the air vent valve 12 is directly connected to the return water pipe 21 to discharge the air in the test pipe.

[0026] The end of the return water pipe 21 is connected to the water storage tank 4 to form a closed-loop water circulation system.

[0027] Specifically, the start-up unloading module 8 includes a start-up unloading valve 801 and a first check valve 802. The inlet of the start-up unloading valve 801 is connected to the outlet of the electric pressure testing pump 7; the outlet of the start-up unloading valve 801 is connected to the inlet of the first check valve 802, and the outlet of the first check valve 802 is connected to the return water pipeline 21 via a pipe. The first check valve 802 only allows the test medium to flow from the start-up unloading valve 801 to the return water pipeline 21, preventing the test medium in the return water pipeline 21 from flowing back to the outlet of the electric pressure testing pump 7, thus avoiding affecting the stability of the pump's output pressure. Before the test begins, the start-up unloading valve 801 is opened, and the test medium output by the electric pressure testing pump 7 flows directly back to the return water pipeline 21 through the first check valve 802, avoiding the high-pressure impact on the downstream pipeline at the moment of pump start-up, achieving "pressureless start-up," and protecting the pump body and pipeline components. When the test is interrupted or ends, start the unloading valve 801 to quickly release the pressure between the outlet of the electric test pump 7 and the start unloading module 8, ensuring that the system pressure returns to zero before shutdown, which facilitates subsequent operations.

[0028] Specifically, the test loading module 9 includes a test solenoid valve 901 and a second check valve 902. The inlet of the test solenoid valve 901 is connected to the outlet of the electric pressure testing pump 7, and the outlet of the test solenoid valve 901 is connected to the inlet of the second check valve 902. The outlet of the second check valve 902 is connected to the inlets of the pulse unloading module 10, the pulse loading module 11, the exhaust valve 12, and the gas cylinder 5 under test. The second check valve 902 only allows water to flow from the test solenoid valve 901 downstream (to the gas cylinder 5 under test and the pulse unloading module 10 and pulse loading module 11), preventing high-pressure water in the gas cylinder 5 or downstream pipeline from flowing back to the electric pressure testing pump 7, thus ensuring stable pressure on the gas cylinder side. The test solenoid valve 901 is controlled by a PLC controller and is the "master switch" for the electric pressure testing pump 7 to supply high-pressure water to the gas cylinder 5 under test, the pulse unloading module 10, and the pulse loading module 11. The test pump 7 is shut off during startup to prevent water from entering the test circuit prematurely; it is turned on during the test to provide power for pressure circulation; and it is shut off in case of failure to cut off the pressure input to the gas cylinder 5 under test. By shutting off the test solenoid valve 901, the electric test pump 7 can be isolated from the downstream test circuit (gas cylinder 5 under test, pulse unloading module 10, and pulse loading module 11), which facilitates separate maintenance of the electric test pump 7 or the downstream test circuit.

[0029] Specifically, the pulse unloading module 10 includes a pulse unloading valve 1001 and a throttle valve 1002. The inlet of the pulse unloading valve 1001 is connected to the outlet of the second one-way valve 902, and the outlet of the pulse unloading valve 1001 is connected to the inlet of the throttle valve 1002. The outlet of the throttle valve 1002 is connected to the return water pipeline 21. The pulse unloading valve 1001 serves as a "pressure relief channel" for the pressure cycle. Controlled by a PLC controller, the pulse unloading valve 1001 opens during the unloading phase, allowing the high-pressure water in the test cylinder 5 to flow back to the return water pipeline 21 via the throttle valve 1002, thus reducing the system pressure from its peak value to its trough value. The throttle valve 1002 precisely controls the water flow rate during unloading by adjusting the channel cross-sectional area, thereby controlling the slope of the pressure drop and ensuring that the pressure change meets the "unloading rate" requirements in the test standard, preventing the test cylinder 5 from being subjected to impact loads due to excessively rapid pressure relief. The pulse unloading module 10 and the pulse loading module 11 work alternately. Through the on / off timing control, the pressure of the gas cylinder fluctuates periodically between the peak value and the valley value to complete the alternating cycle test.

[0030] Specifically, the pulse loading module 11 includes a pulse loading valve 1101 and a back pressure valve 1102. The inlet of the pulse loading valve 1101 is connected to the outlet of the second one-way valve 902, and the outlet of the pulse loading valve 1101 is connected to the inlet of the back pressure valve 1102. The outlet of the back pressure valve 1102 is connected to the return water pipe 21. The pulse loading valve 1101 serves as the "loading channel" for pressure circulation. Controlled by a PLC controller, the pulse loading valve 1101 opens during the loading phase, allowing the high-pressure water output from the electric pressure testing pump 7 to enter the gas cylinder 5 under test through the test loading module 9, pushing the gas cylinder pressure from the valley value to the peak value. The back pressure valve 1102 is set with a fixed opening pressure (i.e., the valley pressure required for the test). During the unloading phase or the initial loading stage, by limiting the leakage flow of the return water pipe 21, it ensures that the system pressure will not fall below the valley value, avoiding test data distortion caused by excessively low pressure. The back pressure valve 1102 can buffer the water flow impact during the loading stage. Combined with the opening and closing speed of the pulse loading valve 1101, it makes the pressure rise process more stable and reduces the interference of pressure fluctuations on the gas cylinder fatigue test results.

[0031] Preferably, in a specific embodiment of this utility model, a mixture of water and ethylene glycol coolant is used to give the test medium an anti-corrosion effect, while increasing the fluidity and lubricity of the test medium. This greatly enhances the test effect and the anti-corrosion ability of the sample, avoids damage to the sample during the test, and improves the reliability of the test results.

[0032] Preferably, the host computer is electrically connected to the PLC controller to transmit user control commands to the PLC controller and generate control signals. The PLC controller is connected to the first pressure sensor 18 and the second pressure sensor 19 to collect pressure data from the outlet of the electric pressure testing pump 7 and the inlet of the gas cylinder 5 under test, and transmits the data to the host computer through the PLC controller. The host computer is equipped with a visualization device, preferably a display screen, which can visualize the pressure data and provide feedback to the operator. The PLC controller is electrically connected to the start-up unloading module 8, the pulse unloading module 10, the pulse loading module 11, and the test loading module 9 to control these modules at different test stages.

[0033] Preferably, a water level sensor 15 is provided at the bottom of the water storage tank 4 to detect the water level in the water storage tank 4. The water level sensor 15 is electrically connected to the PLC controller. When the water level sensor 15 detects that the water level in the water storage tank 4 is lower than the set water level, the PLC controller issues an alarm signal.

[0034] Preferably, a distributor 20 is provided between the gas cylinder 5 to be tested and the water inlet pipe 22, which can connect multiple gas cylinders 5 to be tested. In a specific embodiment of this utility model, a 3-way distributor is preferred to realize multi-station synchronous testing and improve testing efficiency.

[0035] Preferably, the outlet of the electric pressure testing pump 7 is provided with an overflow valve 17. The inlet of the overflow valve 17 is connected to the outlet of the electric pressure testing pump 7, and the outlet of the overflow valve 17 is connected to the return water pipeline 21. When the system pressure exceeds the preset safety value, the overflow valve 17 automatically opens to relieve pressure and prevent the pipeline from being damaged by overpressure.

[0036] Preferably, the outlet of the electric pressure testing pump 7 is also provided with a first shut-off valve 13 and a first pointer pressure gauge 1301. The first shut-off valve 13 is used to manually disconnect the connection between the electric pressure testing pump 7 and the downstream pipeline in an emergency, and the first pointer pressure gauge 1301 is used to visually display the outlet pressure of the electric pressure testing pump 7.

[0037] Preferably, the inlet of the pulse loading valve 1101 is provided with a second shut-off valve 14 and a second pointer pressure gauge 1401. The second shut-off valve 14 is used to cut off the fluid passage when an abnormality occurs in the pulse loading circuit, and the second pointer pressure gauge 1401 is used to display the real-time pressure at the inlet of the pulse loading module 11.

[0038] Reference Figure 2A hydraulic alternating cycle test control device for gas cylinders is fixed on a frame 3. The frame 3 is vertically divided into an upper installation area and a lower installation area. The lower installation area is fixedly equipped with a pipeline pressurization unit with an electric test pump 7 as the core, a pressure sensing unit, and the execution part of the control execution unit. The upper installation area is horizontally divided into a left installation position and a right installation position. A wind cooler 2 is fixedly installed at the left installation position, and a water storage tank 4 is fixedly installed at the right installation position. A control cabinet 1 is fixedly installed on the left side of the frame body. A PLC controller and a host computer are installed in the control cabinet, and the PLC controller is electrically connected to the corresponding components in the upper and lower installation areas. A sample cabinet 6 is fixedly installed on the right side of the frame body. Several gas cylinders 5 to be tested are fixedly installed in the sample cabinet 6. The water inlet of the gas cylinders to be tested is connected to the pipeline pressurization unit through a pipeline.

[0039] Preferably, the air cooler 2 is equipped with a circulating water pipe interface for heat exchange, and the water storage tank 4 is equipped with a connection port that communicates with the circulating water pipe interface. The circulating water pipe interface of the air cooler is connected to the connection port of the water storage tank through the circulating water pipe to form a water circulation loop. The air cooler 2 is equipped with a refrigeration component. When water in the water circulation loop flows into the air cooler 2, the refrigeration component cools the water, and the cooled water flows back to the water storage tank 4, thereby reducing the temperature of the water in the water storage tank 4.

[0040] Preferably, a temperature sensor 16 is provided at the bottom of the water storage tank 4 to detect the water temperature in the water storage tank 4. The temperature sensor 16 is electrically connected to the PLC controller. When the temperature sensor 16 detects that the water temperature in the water storage tank 4 is higher than the set temperature, the PLC controller controls the cooling component of the air cooler 2 to work and cool down the water in the water circulation loop.

[0041] This utility model discloses a hydraulic alternating cycle test control device for gas cylinders, the working process of which is as follows: 1. System Start-up and Unloading Preparation: Before the test begins, the host computer sends a start command to the PLC controller. The PLC controller controls the start unloading valve 801 to open. After the electric test pump 7 starts, the test medium flows directly back to the return water pipeline 21 through the start unloading module 8, realizing the system no-load start-up and avoiding instantaneous high pressure impact.

[0042] 2. After startup, the PLC controller closes the startup unloading valve 801 and opens the test solenoid valve 901 and the exhaust valve 12. The test medium output by the electric test pump 7 enters the gas cylinder 5 under test and each branch through the test loading module 9. The air in the pipeline is discharged through the exhaust valve 12. After the exhaust is completed, the exhaust valve 12 is closed and the system begins to build up pressure.

[0043] 3. Alternating Cyclic Test Loading: The PLC controller controls the pulse loading valve 1101 to open according to the preset parameters, and at the same time closes the pulse unloading valve 1001. The high-pressure test medium output by the electric test pump 7 enters the gas cylinder 5 under test through the test loading module 9. The second pressure sensor 19 monitors the gas cylinder inlet pressure in real time until the pressure reaches the set peak value.

[0044] 4. Alternating Cyclic Test Unloading: When the pressure reaches the set peak value, the PLC controller closes the pulse loading valve 1101 and opens the pulse unloading valve 1001. The test medium in the test cylinder 5 flows back to the return water pipeline 21 through the pulse unloading module 10. The throttle valve 1002 controls the unloading rate, and the back pressure valve 1102 maintains the lowest system pressure (valley value), forming periodic pressure fluctuations.

[0045] 5. During the periodic pressure test, the first pressure sensor 18 monitors the outlet pressure of the electric test pump 7, and the second pressure sensor 19 monitors the real-time pressure of the gas cylinder. Both data are fed back to the PLC controller. The PLC controller adjusts the output power of the electric test pump 7 and the opening and closing sequence of the pulse loading valve 1101 and the pulse unloading valve 1001 to ensure that the pressure alternation curve meets the test standard.

[0046] 6. After the test is completed, the PLC controller closes the test solenoid valve 901, opens the start unloading valve 801 and the exhaust valve 12, the system pressure is released through the return water pipeline 21, and the electric test pressure pump 7 stops running.

[0047] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A hydraulic alternating cycle test control device for gas cylinders, characterized in that, It includes a water storage tank, an air vent valve, a pipeline pressurization unit, a pressure sensing unit, and a control execution unit, wherein: The pipeline pressurization unit includes an electric pressure testing pump, an inlet pipeline, and a return pipeline; The control execution unit includes a PLC controller, a host computer, a start-up unloading module, a pulse unloading module, and a pulse loading module installed between the inlet water pipe and the return water pipe; and a test loading module installed in the inlet water pipe. The pressure sensing unit includes a first pressure sensor disposed at the outlet of the electric pressure testing pump and a second pressure sensor disposed at the inlet of the gas cylinder to be tested. The water storage tank is connected to the inlet of the electric pressure testing pump; the outlet of the electric pressure testing pump is connected to the inlet of the start-up unloading module and the inlet of the test loading module; the outlet of the test loading module is connected to the inlet of the pulse unloading module, the inlet of the pulse loading module, the inlet of the exhaust valve, and the gas cylinder to be tested; the outlets of the start-up unloading module, the pulse unloading module, the pulse loading module, and the exhaust valve are connected to the return water pipeline. The host computer is electrically connected to the PLC controller and is used to transmit user control commands to the PLC controller and generate control signals; the PLC controller is electrically connected to the first pressure sensor, the second pressure sensor, the start-up unloading module, the pulse unloading module, the pulse loading module, and the test loading module.

2. The gas cylinder hydraulic alternating cycle test control device according to claim 1, characterized in that, The bottom of the water tank is equipped with a water level sensor and a temperature sensor, which are used to detect the water level and water temperature in the water tank, respectively.

3. The gas cylinder hydraulic alternating cycle test control device according to claim 1, characterized in that, A cooler is connected to one side of the water tank, and the cooler and the water tank form a water circulation loop to reduce the water temperature in the water tank.

4. The gas cylinder hydraulic alternating cycle test control device according to claim 1, characterized in that, The start-up unloading module includes a start-up unloading valve and a first check valve. The inlet of the start-up unloading valve is connected to the outlet of the electric pressure testing pump; the outlet of the start-up unloading valve is connected to the inlet of the first check valve; and the outlet of the first check valve is connected to the return water pipeline.

5. The gas cylinder hydraulic alternating cycle test control device according to claim 1, characterized in that, The test loading module includes a test solenoid valve and a second check valve. The inlet of the test solenoid valve is connected to the outlet of the electric test pump; the outlet of the test solenoid valve is connected to the inlet of the second check valve; and the outlet of the second check valve is connected to the inlet of the pulse unloading module.

6. The gas cylinder hydraulic alternating cycle test control device according to claim 5, characterized in that, The pulse unloading module includes a pulse unloading valve and a throttle valve. The inlet of the pulse unloading valve is connected to the outlet of the second one-way valve; the outlet of the pulse unloading valve is connected to the inlet of the throttle valve; and the outlet of the throttle valve is connected to the return water pipeline.

7. The hydraulic alternating cycle test control device for gas cylinders according to claim 5, characterized in that, The pulse loading module includes a pulse loading valve and a back pressure valve. The inlet of the pulse loading valve is connected to the outlet of the second one-way valve; the outlet of the pulse loading valve is connected to the inlet of the back pressure valve; and the outlet of the back pressure valve is connected to the return water pipeline.

8. The gas cylinder hydraulic alternating cycle test control device according to claim 1, characterized in that, A diverter is provided between the gas cylinder and the water inlet pipe.

9. The hydraulic alternating cycle test control device for gas cylinders according to claim 1, characterized in that, The electric pressure testing pump is equipped with an overflow valve at its outlet, and the inlet of the overflow valve is connected to the outlet of the electric pressure testing pump; the outlet of the overflow valve is connected to the return water pipeline.

10. The gas cylinder hydraulic alternating cycle test control device according to claim 7, characterized in that, The electric pressure testing pump is equipped with a first shut-off valve and a first pointer pressure gauge at its outlet, which are used to cut off the water flow at the outlet of the electric pressure testing pump in an emergency; the pulse loading valve is equipped with a second shut-off valve and a second pointer pressure gauge at its inlet, which are used to cut off the water flow at the inlet of the pulse loading valve in an emergency.

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