A gas medium pressure fatigue test system

Abstract

The present application relates to the technical field of fatigue test, in particular to a gas medium pressure fatigue test system, the pressurizing device has at least one gas cavity for containing gas medium and at least one liquid cavity communicated with the hydraulic drive circuit, the gas cavity and the liquid cavity are separated by a reciprocating piston; the gas loading circuit is communicated with the gas cavity of the pressurizing device, and is used for connecting at least one or a group of pressure test pieces; the hydraulic drive circuit is used for supplying high-pressure liquid into the liquid cavity of the pressurizing device to drive the reciprocating motion of the piston. The controllable hydraulic power is output through the hydraulic drive circuit, and the liquid pressure energy is converted into gas pressure through the pressurizing device, so that the test system of the present application can apply stable load to the gas cavity, and the problem that direct gas pressurization is difficult to control and has poor safety is solved. Since the loading medium is gas, the test system of the present application can simulate the loading effect of the gas medium on the test piece.

Description

Technical Field

[0001] This invention relates to the field of fatigue testing technology, and more specifically, to a gas medium pressure fatigue testing system. Background Technology

[0002] In the design, manufacturing, and safety assessment of pressure vessels, gas cylinders, and related gas-bearing components, fatigue performance is a key indicator determining their service life and operational safety. To accurately assess the durability of components under real service conditions, fatigue tests must be conducted to simulate the periodic changes in internal gas pressure.

[0003] Currently, fatigue testing of gas-pressure components mainly employs two technical approaches: direct gas circulation pressurization systems and hydraulic fatigue testing systems. Direct gas circulation pressurization systems apply gas pressure loads by periodically charging and discharging the sample using a compressor, gas tank, and control valve assembly. However, due to the strong compressibility of gas, pressure control response is slow and accuracy is low, making it difficult to achieve high-frequency, stable cyclic loading. Furthermore, the rapid flow and release of high-pressure gas pose significant safety hazards, requiring extremely high equipment sealing and pressure resistance, resulting in a complex and expensive system. Hydraulic fatigue testing systems, on the other hand, apply periodic liquid pressure to the sample using hydraulic pumps and cylinders. These systems offer high pressure control accuracy, fast response, and reliability, but the loading medium is a liquid, whose incompressible physical properties differ fundamentally from the pressure fluctuations and impact characteristics of gas in actual service, making it impossible to realistically simulate the loading effect of a gas medium on the component. Summary of the Invention

[0004] The problem solved by this invention is that direct gas pressurization is difficult to control and has poor safety in the prior art.

[0005] To address the above problems, the present invention provides a gas medium pressure fatigue testing system, comprising: Hydraulic drive circuit; A booster device having at least one gas chamber for containing a gaseous medium and at least one liquid chamber in communication with the hydraulic drive circuit, the gas chamber and the liquid chamber being separated by a reciprocating piston; A gas loading circuit, which is connected to the gas chamber of the pressurization device and is used to connect at least one or a group of pressure test specimens; The hydraulic drive circuit is used to supply high-pressure liquid into the liquid chamber of the pressurization device to drive the piston to reciprocate.

[0006] Preferably, the pressurization device includes a first piston chamber and a second piston chamber; a first piston is disposed in the first piston chamber to divide the first piston chamber into a first gas chamber and a first liquid chamber; a second piston is disposed in the second piston chamber to divide the second piston chamber into a second gas chamber and a second liquid chamber; the hydraulic drive circuit alternately supplies high-pressure liquid to the first liquid chamber and the second liquid chamber.

[0007] Preferably, the first liquid chamber and the second liquid chamber are arranged adjacent to each other, and the first gas chamber and the second gas chamber are located on opposite sides of the first liquid chamber and the second liquid chamber, respectively.

[0008] Preferably, the first piston and the second piston are synchronously linked and connected to reciprocate under the action of the hydraulic drive circuit.

[0009] Preferably, the gas loading circuit includes a first loading branch and a second loading branch. The first loading branch is connected to the first gas chamber and is used to connect the first pressure-bearing test piece. The second loading branch is connected to the second gas chamber and is used to connect the second pressure-bearing test piece.

[0010] Preferably, the hydraulic drive circuit includes: A liquid tank is used to store liquid and is connected to the first liquid chamber and the second liquid chamber via pipelines; A hydraulic pump is installed on the pipeline; A reversing valve assembly, installed on the pipeline, is used to switch the flow direction of the liquid medium; The reversing valve assembly has a first working state and a second working state. In the first working state, the reversing valve assembly guides liquid into the first liquid chamber and guides the liquid in the second liquid chamber back to the liquid tank. In the second working state, the reversing valve assembly guides liquid into the second liquid chamber and guides the liquid in the first liquid chamber back to the liquid tank.

[0011] Preferably, a heat exchanger is provided on the gas loading circuit to regulate the temperature of the gas medium entering the pressure test piece.

[0012] Preferably, a buffer tank is provided in the gas loading circuit and / or the hydraulic drive circuit to absorb pressure fluctuations.

[0013] Preferably, it also includes a control system and a monitoring system; The monitoring system includes at least one pressure sensor and / or temperature sensor installed on the gas loading circuit and / or hydraulic drive circuit; The control system is electrically connected to the monitoring system and the electronic control devices on the hydraulic drive circuit. The control system is used to receive feedback signals from the monitoring system and control the operation of the electronic control devices on the hydraulic drive circuit according to the feedback signals.

[0014] Preferably, it also includes a safety protection system, which includes at least one gas discharge safety valve disposed on the gas loading circuit and / or pressurization device, and at least one liquid overflow valve disposed in the hydraulic drive circuit. The liquid overflow valve has its inlet connected to the first liquid chamber and the second liquid chamber, and its outlet connected to the liquid tank.

[0015] The beneficial effects of the gas medium pressure fatigue testing system of the present invention are as follows: the pressurizing device has at least one gas chamber for containing the gas medium and at least one liquid chamber connected to the hydraulic drive circuit. The gas chamber and the liquid chamber are separated by a reciprocating piston, so that the liquid medium and the gas medium are physically completely isolated, and are only connected at the pressure transmission level through the piston. When the system is running, the hydraulic drive circuit supplies high-pressure liquid to the liquid chamber of the pressurizing device. During operation, the hydraulic drive circuit operates according to a predetermined sequence. For example, in one half-cycle, high-pressure liquid enters (i.e., supplies) the liquid chamber, driving the piston to move and do work, the volume of the gas chamber decreases, the gas medium in it is compressed, and the pressure increases; in the next half-cycle, the hydraulic drive circuit depressurizes, causing the high-pressure liquid to flow out (i.e., discharge) the liquid chamber, the liquid chamber pressure decreases, the piston gradually returns to the initial position, the volume of the gas chamber increases, and the pressure decreases. Thus, a periodic pressure change is formed in the gas chamber. This changing gas pressure is transmitted to the interior of the pressure-bearing test piece through the gas loading circuit, thereby realizing gas pressure fatigue loading on the test piece.

[0016] Compared to existing direct gas circulation pressurization systems, the gas medium pressure fatigue testing system of this invention outputs controllable hydraulic power through a hydraulic drive circuit and converts liquid pressure energy into gas pressure through a pressurization device. This allows the testing system to apply a stable load to the gas chamber, solving the problems of difficulty in controlling and poor safety associated with direct gas pressurization. Furthermore, compared to existing hydraulic fatigue testing systems, in this invention, the gas chamber and liquid tank are completely isolated by a piston. High-pressure gas exists only in the sealed gas chamber and gas loading circuit. The pressure load within the gas chamber is applied to the test piece through the gas loading circuit. Because the loading medium is gas, the testing system of this invention can realistically simulate the loading effect of a gas medium on the test piece. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the gas medium pressure fatigue testing system of the present invention; Figure 2for Figure 1 A schematic diagram of the booster device shown.

[0018] Explanation of reference numerals in the attached figures: 1. Pressurization device; 2. First piston chamber; 3. Second piston chamber; 4. First gas chamber; 5. First liquid chamber; 6. First piston; 7. Second gas chamber; 8. Second liquid chamber; 9. Second piston; 10. First loading branch; 11. Second loading branch; 12. First pressure test piece; 13. Second pressure test piece; 14. Gas medium storage tank; 15. Hydraulic pump; 16. Liquid tank; 17. First solenoid valve; 18. Second solenoid valve; 19. Third solenoid valve; 20. Fourth solenoid valve; 21. Heat exchanger; 22. Buffer tank; 23. Pressure sensor; 24. Temperature sensor; 25. Gas safety valve; 26. Liquid overflow valve; 27. Cooler; 28. Liquid level switch; 29. ​​Filter. Detailed Implementation

[0019] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Although some embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the accompanying drawings and embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0020] The term "comprising" and its variations as used herein are open-ended, meaning "including but not limited to"; the term "based on" means "at least partially based on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments"; and the term "optionally" means "optional embodiments". Definitions of other terms will be given in the following description. It should be noted that the concepts of "first," "second," etc., mentioned in this invention are used only to distinguish different devices, modules, or units, and are not intended to limit the order of functions performed by these devices, modules, or units or their interdependencies.

[0021] It should be noted that the terms "a" and "a plurality of" used in this invention are illustrative rather than restrictive. Those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0022] To address the problems existing in the aforementioned related technologies, this embodiment provides a gas medium pressure fatigue testing system. This system is used to apply periodically varying gas pressure loads to pressure-bearing test specimens to simulate their actual stress conditions under service conditions. Figure 1 As shown, the test system includes a hydraulic drive circuit, a booster device 1, and a gas loading circuit.

[0023] First, the hydraulic drive circuit is the power source for the entire system. This circuit is used to provide a liquid medium with a preset pressure and is connected to the subsequent pressurization device 1 via pipeline. Specifically, the hydraulic drive circuit may include components such as a hydraulic pump 15, a liquid tank 16, and a valve group for controlling the flow of liquid, and its function is to supply high-pressure liquid to the liquid chamber of the pressurization device 1.

[0024] The pressurization device 1 has at least one gas chamber for containing the gaseous medium and at least one liquid chamber connected to the hydraulic drive circuit. The gas chamber and the liquid chamber are separated by a reciprocating piston, so that the liquid medium and the gaseous medium are physically completely isolated, and are only connected at the pressure transmission level through the piston. This isolation design can effectively avoid the contamination of the gaseous test medium by the hydraulic medium, and also prevent the safety hazards caused by high-pressure gas entering the hydraulic system.

[0025] The gas loading circuit is used to guide the compressed gas medium to the pressure test specimen. The gas loading circuit is connected to the gas chamber of the pressurization device 1 and to at least one or a group of pressure test specimens. The pressure test specimen is an object such as a pressure vessel or gas cylinder that needs to undergo fatigue testing.

[0026] When the system is running, the hydraulic drive circuit supplies high-pressure liquid to the liquid chamber of the pressurization device 1. During operation, the hydraulic drive circuit operates according to a predetermined sequence. For example, in one half-cycle, high-pressure liquid enters (i.e., supplies) the liquid chamber, driving the piston to move and do work. The volume of the gas chamber decreases, the gas medium inside is compressed, and the pressure increases. In the next half-cycle, the hydraulic drive circuit depressurizes, causing the high-pressure liquid to flow out (i.e., discharge) the liquid chamber. The pressure in the liquid chamber decreases, the piston gradually returns to its initial position, the volume of the gas chamber increases, and the pressure decreases. Thus, a periodic pressure change is formed in the gas chamber. This changing gas pressure is transmitted to the interior of the pressure-bearing test piece via the gas loading circuit, thereby achieving gas pressure fatigue loading on the test piece.

[0027] In summary, the test system of this embodiment has a hydraulic drive circuit that can output controllable and stable hydraulic power. Through the isolation design in the pressurization device 1, the liquid pressure energy is converted into gas pressure, enabling the test system of this embodiment to apply a stable load to the gas chamber. This solves the problems of difficulty in controlling and poor safety of direct gas pressurization. Since the gas chamber and liquid chamber are completely isolated by the piston, the high-pressure gas exists only in the sealed gas chamber and gas loading circuit. The pressure load in the gas chamber is applied to the test piece through the gas loading circuit. The loading medium is always gas. Therefore, the test system of this embodiment can realistically simulate the loading effect of the gas medium on the test piece.

[0028] As a further optimization, in order to achieve alternating loading of two or more pressure-bearing test specimens within a single pressurizing device 1, this embodiment constructs the pressurizing device 1 as containing two relatively independent working chambers. Specifically, the pressurizing device 1 includes a first piston chamber 2 and a second piston chamber 3. These two piston chambers are physically separated independent cavity structures, each used to cooperate with different pressure-bearing test specimens. Furthermore, to enable each piston chamber to independently compress and release gas, this embodiment provides a piston within each piston chamber. Specifically, a first piston 6 is provided within the first piston chamber 2, which divides the internal space of the first piston chamber 2 into a first gas chamber 4 and a first liquid chamber 5, which are not interconnected. The first gas chamber 4 is used to contain the gas medium and is connected to the first pressure-bearing test specimen 12, while the first liquid chamber 5 is connected to the hydraulic drive circuit. Similarly, a second piston 9 is provided within the second piston chamber 3, which divides the internal space of the second piston chamber 3 into a second gas chamber 7 and a second liquid chamber 8, which are not interconnected. With this separation method, the liquid pressure provided by the hydraulic drive circuit can act on the piston, thereby driving the piston to move and change the volume of the gas chamber, thus achieving the compression or expansion of the gas.

[0029] To achieve alternating pressurization and depressurization of the two gas chambers, thereby applying continuous cyclic loads to the two pressure-bearing test specimens, the hydraulic drive circuit alternately supplies high-pressure liquid to the first liquid chamber 5 and the second liquid chamber 8. "Alternating supply" means that during one working period, high-pressure liquid is fed into the first liquid chamber 5, while liquid in the second liquid chamber 8 is allowed to drain; in the next working period, high-pressure liquid is fed into the second liquid chamber 8, while liquid in the first liquid chamber 5 is allowed to drain. This cycle repeats continuously. By setting up two independent piston chambers and corresponding first piston 6 and second piston 9, a pressurization device 1 can simultaneously drive two independent gas loading circuits, providing a structural basis for simultaneously testing two or more sets of pressure-bearing test specimens. Furthermore, by alternately supplying high-pressure liquid to the two liquid chambers through the hydraulic drive circuit, the alternating reciprocating motion of the two pistons is achieved, thereby enabling the two gas chambers to alternately compress (pressurize) and release (depressurize) the gas. This alternating working mode allows the system to operate in a continuous cycle where, while one gas chamber outputs high-pressure gas to the pressure test specimen connected to it, another gas chamber draws low-pressure gas back from the pressure test specimen connected to it, preparing for the next pressurization stroke.

[0030] As a further optimization, the first liquid chamber 5 and the second liquid chamber 8 are arranged adjacent to each other, and the first gas chamber 4 and the second gas chamber 7 are located on opposite sides of the first liquid chamber 5 and the second liquid chamber 8, respectively. "Adjacent arrangement" means that the two liquid chambers are spatially close to each other; in other words, as... Figure 2 As shown in the diagram, from an overall layout perspective, the pressurizing device 1 forms a structure in which the first gas chamber 4, the first piston 6, the first liquid chamber 5, the second liquid chamber 8, the second piston 9, and the second gas chamber 7 are arranged in sequence. As a possible implementation, those skilled in the art can change the overall layout; for example, it can be changed to the first liquid chamber 5, the first piston 6, the first gas chamber 4, the second liquid chamber 8, the second piston 9, and the second gas chamber 7. Of course, other layout changes are also possible, which will not be elaborated upon here.

[0031] In this embodiment, the first piston 6 is located between the first gas chamber 4 and the first liquid chamber 5, serving to separate these two chambers; the second piston 9 is located between the second gas chamber 7 and the second liquid chamber 8, serving to separate these two chambers. Since the first liquid chamber 5 and the second liquid chamber 8 are arranged adjacent to each other, and the two gas chambers are located on opposite sides, as... Figure 2As shown, when the hydraulic drive circuit supplies high-pressure liquid to the first liquid chamber 5, the volume of the first liquid chamber 5 increases, pushing the first piston 6 towards the first gas chamber 4 (moving to the left), compressing the gas in the first gas chamber 4. Simultaneously, the hydraulic drive circuit allows liquid to drain from the second liquid chamber 8, reducing the volume of the second liquid chamber 8. Under the pressure of the gas in the second gas chamber 7, the second piston 9 moves towards the second liquid chamber 8 (also to the left), increasing the volume of the second gas chamber 7 and drawing gas from the pressure-bearing test piece connected to it. Conversely, when the hydraulic drive circuit supplies high-pressure liquid to the second liquid chamber 8, both pistons move simultaneously to the right, compressing the second gas chamber 7 and increasing the volume of the first gas chamber 4 to draw in gas. Therefore, the two pistons always move in the same direction, either simultaneously to the left or simultaneously to the right.

[0032] Based on the above layout, the adjacent arrangement of the two liquid chambers allows for a centralized arrangement of the hydraulic drive circuit's supply lines, simplifying the connection structure between the hydraulic system and the booster device 1. More importantly, this layout naturally creates a synchronized "advancing and retracting" relationship between the two pistons. That is, when one piston compresses gas, the other piston simultaneously expands its volume to draw in gas, and the gas reciprocates between the two gas chambers and the connected pressure-bearing test piece. This unidirectional motion design ensures that the inertial forces generated by the two pistons during reciprocating motion are in the same direction, facilitating balancing through counterweights or synchronization mechanisms, thereby reducing system vibration and improving loading stability.

[0033] To further ensure that the two pistons maintain a coordinated motion during reciprocating motion, the first piston 6 and the second piston 9 are synchronously linked to reciprocate under the action of the hydraulic drive circuit. This synchronous linkage can be achieved through various mechanical connection methods. For example, the first piston 6 and the second piston 9 can be fixedly connected by a piston rod passing through the first liquid chamber 5 and the second liquid chamber 8, forming a "double-headed piston" structure; or, the first piston 6 and the second piston 9 can be motionally coupled through transmission components such as gear and rack mechanisms or linkage mechanisms to ensure that they move synchronously.

[0034] Synchronous linkage ensures precise synchronization of the two piston movements, achieving strict matching of the volume changes of the two gas chambers without relying on complex electronic control systems or hydraulic synchronization circuits, thus ensuring smooth gas transfer between the two test pieces. More importantly, this synchronous linkage design allows the hydraulic drive circuit to control only the total flow rate and direction of the liquid, eliminating the need to separately control the inlet and outlet timing of the two liquid chambers, greatly simplifying the control logic and improving system reliability. For example, when using a double-piston structure, the entire moving part becomes a single unit, and the hydraulic system only needs to alternately supply liquid to the two liquid chambers to achieve alternating compression and release of the two gas chambers, resulting in a simple and reliable control method.

[0035] As a further optimization, the gas loading circuit includes a first loading branch 10 and a second loading branch 11. The first loading branch 10 is connected to the first gas chamber 4 and is used to connect to the first pressure-bearing test piece 12. The compressed high-pressure gas in the first gas chamber 4 can be transported to the first pressure-bearing test piece 12 via the first loading branch 10 to apply a pressure load to the first pressure-bearing test piece 12. When the volume of the first gas chamber 4 increases and it is in a suction state, the gas in the first pressure-bearing test piece 12 flows back to the first gas chamber 4 via the first loading branch 10 to achieve pressure relief. Similarly, the second loading branch 11 is connected to the second gas chamber 7 of the pressurization device 1, and the end of the second loading branch 11 away from the second gas chamber 7 is used to connect to the second pressure-bearing test piece 13, thereby realizing gas transmission between the second gas chamber 7 and the second pressure-bearing test piece 13. To ensure the smoothness and controllability of gas transmission, components such as shut-off valves, check valves, or flow control valves are installed on the pipeline when necessary.

[0036] By setting up two independent loading branches, one pressurizing device 1 can simultaneously serve two pressure test specimens, fully utilizing the structural advantages of the pressurizing device 1 and significantly improving test efficiency. Secondly, the two loading branches are independent and do not interfere with each other, allowing the first pressure test specimen 12 and the second pressure test specimen 13 to withstand independent gas pressure cycles. Even if the volume or pressure characteristics of the two test specimens differ, they will not affect each other, ensuring the accuracy and reliability of the test data.

[0037] As a further optimization, the hydraulic drive circuit includes a hydraulic pump 15, a liquid tank 16, and a directional valve assembly. The hydraulic pump 15 draws liquid medium from the liquid tank 16 and pressurizes it to provide the system with high-pressure liquid at a set pressure. The specific type of hydraulic pump 15 can be selected according to the test pressure requirements and flow rate demands; for example, a piston pump, gear pump, or vane pump can be used. The liquid tank 16 stores the liquid medium and provides sufficient liquid capacity for the entire hydraulic system. A level switch 28 is installed on the liquid tank 16 to monitor the liquid level in real time. When the liquid medium in the liquid tank 16 falls below the set level, the level switch 28 issues an alarm signal or controls the hydraulic pump 15 to stop, preventing cavitation or damage to the hydraulic pump 15 due to air intake. The directional valve assembly is connected between the outlet of the hydraulic pump 15, the return port of the liquid tank 16, and the first liquid chamber 5 and the second liquid chamber 8, forming a complete hydraulic control circuit. The directional valve assembly can take various forms, such as electromagnetic directional valves, electro-hydraulic directional valves, or manual directional valves, selected according to the requirements of control precision and automation. The directional valve assembly has a first operating state and a second operating state. In the first operating state, the oil circuit inside the directional valve assembly is in a first connected mode. At this time, the high-pressure liquid output from the hydraulic pump 15 is guided into the first liquid chamber 5, pushing the first piston 6 to move; simultaneously, the low-pressure liquid in the second liquid chamber 8 is guided back to the liquid tank 16. This oil circuit connection method achieves pressurized supply to the first liquid chamber 5 and depressurized drainage of the second liquid chamber 8. In the second operating state, the oil circuit inside the directional valve assembly switches to a second connected mode. At this time, the high-pressure liquid output from the hydraulic pump 15 is guided into the second liquid chamber 8, pushing the second piston 9 to move; simultaneously, the low-pressure liquid in the first liquid chamber 5 is guided back to the liquid tank 16. This oil circuit connection method achieves pressurized supply to the second liquid chamber 8 and depressurized drainage of the first liquid chamber 5.

[0038] By periodically switching between the first and second operating states using the reversing valve assembly, the hydraulic drive circuit can alternately supply high-pressure liquid to the first liquid chamber 5 and the second liquid chamber 8, thereby driving the first piston 6 and the second piston 9 to reciprocate, realizing the alternating compression and release of the first gas chamber 4 and the second gas chamber 7. Specifically, the reversing valve assembly in this embodiment includes a first solenoid valve 17, a second solenoid valve 18, a third solenoid valve 19, and a fourth solenoid valve 20. The first solenoid valve 17 is located on the return line between the first liquid chamber 5 and the liquid tank 16; the second solenoid valve 18 is located on the supply line between the hydraulic pump 15 and the first liquid chamber 5; the third solenoid valve 19 is located on the supply line between the hydraulic pump 15 and the second liquid chamber 8; and the fourth solenoid valve 20 is located on the return line between the second liquid chamber 8 and the liquid tank 16. In this embodiment, as... Figure 1As shown, the design of each pipeline is adjusted to simplify the pipeline. The inlets of the second solenoid valve 18 and the third solenoid valve 19 are connected to the outlet of the hydraulic pump 15, and their outlets are connected to the first liquid chamber 5 and the second liquid chamber 8, respectively. The inlets of the first solenoid valve 17 and the fourth solenoid valve 20 are connected to the outlets of the second solenoid valve 18 and the third solenoid valve 19, respectively, and their outlets are connected to the liquid tank 16.

[0039] During operation, the reversing valve assembly switches the on / off states of each solenoid valve to achieve alternating liquid supply and drainage between the first liquid chamber 5 and the second liquid chamber 8. For example... Figure 1 As shown, in the first operating state, the first solenoid valve 17 and the third solenoid valve 19 are closed, while the second solenoid valve 18 and the fourth solenoid valve 20 are open. At this time, the oil circuit inside the directional valve assembly is in the first connected mode. The high-pressure liquid output by the hydraulic pump 15 enters the first liquid chamber 5 through the second solenoid valve 18, pushing the first piston 6 to move; simultaneously, the low-pressure liquid in the second liquid chamber 8 flows back to the liquid tank 16 through the fourth solenoid valve 20. In the second operating state, the first solenoid valve 17 and the third solenoid valve 19 are open, while the second solenoid valve 18 and the fourth solenoid valve 20 are closed. At this time, the oil circuit inside the directional valve assembly switches to the second connected mode. The high-pressure liquid output by the hydraulic pump 15 sequentially enters the second liquid chamber 8 through the third solenoid valve 19, pushing the second piston 9 to move; simultaneously, the low-pressure liquid in the first liquid chamber 5 flows back to the liquid tank 16 through the first solenoid valve 17.

[0040] By coordinating and switching the four solenoid valves, the directional valve assembly periodically switches between the first and second operating states, thereby achieving alternating fluid supply to the first liquid chamber 5 and the second liquid chamber 8, driving the piston assembly to reciprocate continuously. This valve arrangement allows the hydraulic pump 15 to operate continuously without frequent start-stop, effectively reducing the impact of motor start-stop and extending the service life of the equipment. At the same time, the rapid switching of the valve assembly ensures the high-frequency response of the piston reciprocating motion.

[0041] As a further optimization, a heat exchanger 21 is provided on the gas loading circuit to regulate the temperature of the gas medium entering the pressure-bearing test specimen. When the gas medium flows from the gas chamber to the pressure-bearing test specimen, it inevitably passes through the heat exchanger 21, thus ensuring that all gas entering the pressure-bearing test specimen undergoes temperature regulation. Depending on the specific test requirements, the heat exchanger 21 can adopt various structural forms, such as a shell-and-tube heat exchanger 21, a plate heat exchanger 21, or a coaxial heat exchanger 21. When the first gas chamber 4 or the second gas chamber 7 of the pressurizing device 1 compresses the gas, the compressed high-pressure gas first flows through the heat exchanger 21. The heat exchange medium inside the heat exchanger 21 exchanges heat with the gas medium, regulating the gas temperature to a preset target value. Then, the regulated gas enters the pressure-bearing test specimen through the gas loading circuit, applying a pressure load under specific temperature conditions to the test specimen. Similarly, when the gas flows back from the pressure test piece to the gas chamber, it will flow through the heat exchanger 21 again. At this time, the heat exchanger 21 can choose whether to continue to regulate the temperature of the returning gas as needed.

[0042] By actively regulating the temperature of the gas medium through heat exchanger 21, the temperature of the gas entering the pressure test specimen can be precisely controlled within the target range, thereby simulating the real temperature environment that the pressure test specimen experiences under actual service conditions. More importantly, for certain special gas media (such as supercritical carbon dioxide), temperature changes directly affect the gas's density, viscosity, and compressibility, thus influencing the transmission of pressure loads and fatigue damage mechanisms. Precise temperature control allows for a more accurate reproduction of the physical properties and pressure fluctuation behavior of the gas medium under actual service conditions, thereby improving the reliability and engineering reference value of the test data. For example, in the fatigue test of a supercritical carbon dioxide storage tank, maintaining the carbon dioxide gas temperature at approximately 50°C through heat exchanger 21 keeps it in a supercritical state, realistically simulating the internal medium state and pressure change patterns of the storage tank during actual operation.

[0043] As a further optimization, such as Figure 1As shown, the buffer tank 22 is installed in the hydraulic drive circuit. Specifically, the buffer tank 22 is connected to the output pipeline of the hydraulic pump 15, located between the outlet of the hydraulic pump 15 and the reversing valve assembly. In this configuration, the buffer tank 22 is used to absorb the pressure pulsations generated during the operation of the hydraulic pump 15. Since the hydraulic pump 15 (especially a piston pump) periodically draws in and discharges liquid during operation, pressure pulsations and flow fluctuations are inevitable. These fluctuations are transmitted to the liquid chamber of the booster device 1, thus affecting the smoothness of piston movement and the stability of gas pressure. As an alternative implementation, the buffer tank 22 can be installed in the gas loading circuit. Specifically, the buffer tank 22 is connected in series or parallel to the gas loading circuit, located on the pipeline between the gas chamber of the booster device 1 and the pressure test piece, or located near the interface of the pressure test piece. In this configuration, the buffer tank 22 is used to absorb the pressure pulsations generated during the compression and release of the gas medium. Because of the high compressibility of gas, gas pressure is prone to spikes or fluctuations when the piston reverses direction or the valve switches. The gas volume in the buffer tank 22 can absorb these instantaneous pressure changes through its own compression and expansion, making the gas pressure entering the pressure test piece more stable.

[0044] As a further optimization, the test system in this embodiment includes a control system and a monitoring system. The monitoring system is used to collect key status parameters of the system in real time. Specifically, the monitoring system includes pressure sensors 23 and temperature sensors 24 installed on the gas loading circuit and / or the hydraulic drive circuit. When the monitoring system is installed on the gas loading circuit, at least one pressure sensor 23 is installed to detect the real-time pressure value of the gas medium in the loading circuit; at least one temperature sensor 24 is installed to detect the real-time temperature value of the gas medium. The number and installation positions of the pressure sensors 23 and temperature sensors 24 can be adaptively configured according to monitoring requirements. For example, a first pressure sensor 23 can be installed at the outlet of the first gas chamber 4 to monitor the output pressure of the first gas chamber 4; a second pressure sensor 23 can be installed at the outlet of the second gas chamber 7 to monitor the output pressure of the second gas chamber 7; and a temperature sensor 24 can be installed on the outlet side of the heat exchanger 21 to monitor the temperature of the gas entering the pressure-bearing test piece. These sensors convert the collected pressure and temperature signals into electrical signals and transmit them to the control system in real time. Similarly, when the monitoring system is installed on the hydraulic drive circuit, the number and installation position of the pressure sensor 23 and temperature sensor 24 are also adapted according to the monitoring requirements, which will not be elaborated here.

[0045] The control system is electrically connected to the monitoring system and the electronically controlled components in the hydraulic drive circuit. Specifically, these electronically controlled components refer to the hydraulic pump 15, the directional valve assembly, the heat exchanger, the buffer tank, and various sensors. The control system typically uses a programmable logic controller (PLC) or an industrial computer to receive feedback signals from the monitoring system and control the operation of the hydraulic drive circuit based on these signals. Specifically, the control system compares the received measured pressure value with a preset target pressure curve. When the measured pressure value deviates from the set range, the control system generates corresponding control commands based on the deviation and outputs them to the electronically controlled components in the hydraulic drive circuit to adjust their operating state. For example, the control system can control the switching timing and frequency of the directional valve assembly to change the cycle of the piston's reciprocating motion; or control the start / stop and output flow of the hydraulic pump 15 to adjust the piston's speed, thereby adjusting the pressure output value in the gas chamber.

[0046] As a further optimization, the test system in this embodiment includes a safety protection system. A gas safety valve 25 is installed in the gas loading circuit and / or the pressurization device. Specifically, a first gas safety valve 25 can be installed in the first loading branch 10 to automatically open and release pressure when the gas pressure in the first gas chamber 4 or the first pressure-bearing test piece 12 exceeds a set threshold; a second gas safety valve 25 can be installed in the second loading branch 11 to automatically open and release pressure when the gas pressure in the second gas chamber 7 or the second pressure-bearing test piece 13 exceeds a set threshold; or it can be installed in the gas chamber of the pressurization device. The gas safety valve 25 is typically a spring-loaded safety valve, whose opening pressure is set according to the system's maximum allowable operating pressure, does not rely on an external power source, and can operate independently in the event of a control system failure.

[0047] A liquid relief valve 26 is installed in the hydraulic drive circuit. Specifically, the inlet of the liquid relief valve 26 is connected to the first liquid chamber 5 and the second liquid chamber 8, and the outlet is connected to the liquid tank 16. When the liquid pressure in the first liquid chamber 5 or the second liquid chamber 8 exceeds a set threshold due to abnormal conditions, the relief valve automatically opens, directly returning the high-pressure liquid to the liquid tank 16, limiting the liquid pressure within a safe range, and preventing damage to the hydraulic system due to overpressure.

[0048] As a further optimization, a filter 29 and a cooler 27 are sequentially arranged along the direction of liquid flow into the hydraulic pump 15. The cooler 27 regulates the temperature of the circulating liquid medium, preventing the liquid medium temperature from exceeding the equipment's allowable operating temperature range due to prolonged continuous operation of the motor and hydraulic pump 15. The filter 29 removes impurities from the liquid medium, ensuring its cleanliness and preventing impurities from entering the hydraulic system and affecting the normal operation stability and service life of the hydraulic components. Through the installation of the cooler 27 and the filter 29, this embodiment effectively achieves active control of the liquid medium temperature and continuous assurance of medium purity, thereby ensuring the operational stability and reliability of the hydraulic drive circuit under long-term continuous operation.

[0049] As a further optimization, this embodiment also includes a gas medium storage tank 14, whose two ends are respectively connected to the first gas chamber 4 and the second gas chamber 7 to replenish the first gas chamber 4 and the second gas chamber 7 with gas medium.

[0050] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.

Claims

1. A gas medium pressure fatigue testing system, characterized in that, include: Hydraulic drive circuit; A booster device (1) has at least one gas chamber for containing a gas medium and at least one liquid chamber connected to the hydraulic drive circuit, the gas chamber and the liquid chamber being separated by a reciprocating piston; A gas loading circuit is connected to the gas chamber of the pressurization device (1) and is used to connect at least one or a group of pressure test specimens; The hydraulic drive circuit is used to supply high-pressure liquid to the liquid chamber of the booster device (1) to drive the piston to reciprocate.

2. The gas medium pressure fatigue testing system according to claim 1, characterized in that, The booster device (1) includes a first piston chamber (2) and a second piston chamber (3); a first piston (6) is provided in the first piston chamber (2) to divide the first piston chamber (2) into a first gas chamber (4) and a first liquid chamber (5); a second piston (9) is provided in the second piston chamber (3) to divide the second piston chamber (3) into a second gas chamber (7) and a second liquid chamber (8); the hydraulic drive circuit alternately supplies high-pressure liquid to the first liquid chamber (5) and the second liquid chamber (8).

3. The gas medium pressure fatigue testing system according to claim 2, characterized in that, The first liquid chamber (5) and the second liquid chamber (8) are arranged adjacent to each other, and the first gas chamber (4) and the second gas chamber (7) are located on opposite sides of the first liquid chamber (5) and the second liquid chamber (8), respectively.

4. The gas medium pressure fatigue testing system according to claim 3, characterized in that, The first piston (6) and the second piston (9) are synchronously linked and reciprocate under the action of the hydraulic drive circuit.

5. The gas medium pressure fatigue testing system according to claim 2, characterized in that, The gas loading circuit includes a first loading branch (10) and a second loading branch (11). The first loading branch (10) is connected to the first gas chamber (4) and is used to connect the first pressure test piece (12). The second loading branch (11) is connected to the second gas chamber (7) and is used to connect the second pressure test piece (13).

6. The gas medium pressure fatigue testing system according to any one of claims 2-5, characterized in that, The hydraulic drive circuit includes: A liquid tank (16) is used to store liquid and is connected to the first liquid chamber (5) and the second liquid chamber (8) via a pipeline; A hydraulic pump (15) is installed on the pipeline; A reversing valve assembly, installed on the pipeline, is used to switch the flow direction of the liquid medium; The reversing valve assembly has a first working state and a second working state. In the first working state, the reversing valve assembly guides liquid into the first liquid chamber (5) and guides the liquid in the second liquid chamber (8) back to the liquid tank (16). In the second working state, the reversing valve assembly guides liquid into the second liquid chamber (8) and guides the liquid in the first liquid chamber (5) back to the liquid tank (16).

7. The gas medium pressure fatigue testing system according to any one of claims 1-5, characterized in that, A heat exchanger (21) is provided on the gas loading circuit to regulate the temperature of the gas medium entering the pressure test piece.

8. The gas medium pressure fatigue testing system according to any one of claims 1-5, characterized in that, A buffer tank (22) is provided in the gas loading circuit and / or the hydraulic drive circuit to absorb pressure fluctuations.

9. The gas medium pressure fatigue testing system according to any one of claims 1-5, characterized in that, It also includes control and monitoring systems; The monitoring system includes at least one pressure sensor (23) and / or temperature sensor (24) disposed on the gas loading circuit and / or hydraulic drive circuit. The control system is electrically connected to the monitoring system and the electronic control devices on the hydraulic drive circuit. The control system is used to receive feedback signals from the monitoring system and control the operation of the electronic control devices on the hydraulic drive circuit according to the feedback signals.

10. The gas medium pressure fatigue testing system according to claim 6, characterized in that, It also includes a safety protection system, which includes at least one gas discharge safety valve (25) disposed on the gas loading circuit and / or pressurization device (1), and at least one liquid overflow valve (26) disposed in the hydraulic drive circuit. The inlet of the liquid overflow valve (26) is connected to the first liquid chamber (5) and the second liquid chamber (8), and the outlet is connected to the liquid tank (16).

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