A pressurized hydraulic oil tank and a pressurization force control method

Abstract

A kind of pressurized hydraulic oil tank and pressurized force control method, the hydraulic oil tank pressurized hydraulic oil tank, including the spacing between the closed tank partition and the inner wall of tank forms upper and lower passages, upper and lower passages are used to connect oil return cavity and oil suction cavity, oil return filter is suspended installation outside the tank, and is inserted into the oil return cavity of tank by oil return pipe through the connection of oil return pipe line, oil suction filter is installed in the side of tank, oil suction filter cartridge is inserted into the inside of oil suction cavity and relies on middle position, gas pressure control valve group is installed outside the tank, and is connected on the gas pressure interface b of the upper cover plate of tank by pipeline.This application's hydraulic oil tank structure is compact, convenient to carry, can be designed into smaller volume, and has strong versatility, can be used in the field of engineering machinery under high altitude low pressure environment, especially track car, railway engineering machinery.

Description

Technical Field

[0001] This invention relates to the field of hydraulic technology, specifically to a pressurized hydraulic oil tank and a pressure control method. Background Technology

[0002] A hydraulic oil tank is a container used to store the hydraulic fluid required for the normal operation of a hydraulic system. It also circulates and filters the oil, settles impurities and condensate, defoams and releases gases mixed in with the oil returning from the system, and monitors oil temperature and quality. The hydraulic oil tank is a core component ensuring the continuous and stable operation of the hydraulic system. The self-priming capability of a hydraulic pump is related to atmospheric pressure. In high-altitude environments with low atmospheric pressure, the pump's starting self-priming capability is greatly reduced. If the pump draws in cavitation, it will fail to pump oil normally, causing abnormal noises, cavitation, localized wear, or even damage. Summary of the Invention

[0003] To overcome the aforementioned deficiencies of existing technologies, this invention proposes a pressurized hydraulic oil tank with a structure that facilitates pressurization. This is achieved by installing removable, bolt-fixed transverse partitions at locations most prone to bulging and deformation during pressurization, thereby improving the overall rigidity of the tank and facilitating subsequent maintenance and cleaning. Furthermore, this invention also proposes a method for controlling the pressure of the hydraulic oil tank. By depressurizing a high-pressure air source and controlling the timing of pressurization according to system operating conditions, the pressure inside the tank is increased to a level higher than that of the external atmosphere. This enhances the self-priming capability of the hydraulic system's oil pump in low-pressure environments, solving the problem of difficult self-priming of the oil pump in high-altitude, low-pressure environments and maintaining the normal operation of the hydraulic system.

[0004] The technical solution of the present invention is as follows: a pressurized hydraulic oil tank includes a closed tank body partition and an inner wall of the tank body forming an upper and lower channel. The upper and lower channel is used to connect the return oil chamber and the suction oil chamber. The return oil filter is suspended and installed on the outside of the tank body and is inserted into the return oil chamber of the tank body through the return oil pipe. The suction oil filter is installed on the side of the tank body and the suction oil filter cartridge is inserted into the middle position inside the suction oil chamber, mainly to minimize the suction resistance and to avoid the lower position to avoid sucking in the sedimented impurities. The air pressure control valve group is installed on the outside of the tank body and is connected to the air pressure interface b on the upper cover plate of the tank body through a pipeline.

[0005] The diaphragm is fixedly installed in the middle of the box by bolts, dividing the box into two parts: the oil return chamber and the oil suction chamber. The length and width of the diaphragm are smaller than the length and width of the inner cavity of the box. An air filter is provided on the upper cover.

[0006] The outer wall of the oil return chamber of the housing is equipped with several drain port assemblies for connecting to drain pipes in the hydraulic system. These drain port assemblies are connected to the oil return chamber of the housing via drain pipes, the ends of which are beveled. The end of the drain pipe should be below the minimum allowable liquid level in the hydraulic tank but above the bottom of the oil return chamber. This prevents the returned oil from splashing directly onto the surface, creating foam and bubbles, or from directly impacting the bottom of the oil return chamber, stirring up impurities and hindering sedimentation. The beveled surface primarily facilitates oil diffusion, preventing the returned oil from directly impacting the bottom and causing significant turbulence, which is detrimental to impurity deposition. The diaphragm acts as the bottom of the oil return chamber. The end of the drain pipe should be above the bottom of the oil return chamber, generally required to be at least 100mm higher, and even in extreme cases, at least 50mm higher. This beveled design promotes oil diffusion and prevents high-speed, direct jets of oil from impacting the bottom, causing significant oil agitation and hindering impurity deposition.

[0007] The suction filter cartridge of the suction filter is inserted into the return oil chamber of the housing. The return oil filter, installed outside the housing, is connected to the return oil chamber via a return oil pipe. The end of the return oil pipe is beveled. There is only one return oil pipe, which is directly connected to the outlet of the return oil filter.

[0008] The air pressure control valve assembly is installed outside the housing. The air pressure control valve assembly includes an air supply port a, a throttle valve, a filter, a shut-off solenoid valve, a pressure gauge, a pressure reducing valve, a check valve, and the pressure gauge is connected in sequence and connected to the air pressure interface b on the top of the housing through a pipeline.

[0009] The enclosed tank is a cuboid structure assembled by welding left, right, front, and rear uprights to a bottom plate, and then using bolts and sealing gaskets to connect the top cover plate. A level gauge with a recessed mounting plate is installed on the right outer wall of the tank, corresponding to the oil return chamber. Lifting lugs are provided on the left and right outer walls of the tank, mounting seats are provided on the left and right sides of the bottom plate, and several threaded seats are provided on the front outer wall. The level sensor is used to monitor the real-time level of the hydraulic oil tank and to detect sudden leaks in the hydraulic system. The temperature sensor is used to monitor the temperature of the hydraulic oil in the tank and to detect abnormal temperature rises caused by component failures in the hydraulic system. An oil drain port is located at the lowest point on the right side of the bottom of the tank and is sealed with a plug.

[0010] A method for controlling the pressure of a pressurized hydraulic oil tank includes the following steps:

[0011] S1, Connection of the hydraulic system

[0012] One end of the drain pipe in the hydraulic system is connected to the drain port assembly on the outer wall of the return oil chamber of the hydraulic oil tank, and the other end is connected to the oil supply port of the hydraulic system. One end of the return oil pipe in the hydraulic system is connected to the return oil interface c on the return oil filter installed outside the tank, and the other end is connected to the oil supply port of the hydraulic system. One end of the suction pipe in the hydraulic system is connected to the suction port d, and the other end is connected to the oil pump suction port of the hydraulic system to supply oil to the pump. This allows the hydraulic oil tank to be connected to the hydraulic system, forming a complete circulation loop system.

[0013] S2. Calibration of initial parameters

[0014] Install the pneumatic pressure control valve assembly on the hydraulic test bench and apply pressure and flow rate (the applied flow rate and pressure are determined according to the rated parameters of the air source that can be provided by the vehicle). Based on the preset pressure value A of the air filter and the maximum value C that the tank can withstand, determine the pressure target value B of the pressure reducing valve, where C > A ≥ B. Adjust the throttle valve opening to the minimum state. To avoid excessive air pressure flow due to excessive opening during the initial start-up of the system, which could cause the tank to burst, the throttle valve opening should be adjusted to the minimum to facilitate the safe start-up of the system. The preset pressure value A of the air filter on the upper cover plate is determined in the initial design stage based on the actual operating conditions of the hydraulic system. A = tank pressure value.

[0015] S3, Installation parameter settings

[0016] Based on the chamber volume V, the pressurization time T, and the pressurization target value B, calculate the flow rate q corresponding to the opening degree that the throttle valve needs to be set, q=αBV / T, where α is a calculation constant;

[0017] S31. The pneumatic control valve assembly is installed outside the housing to form a pressurized hydraulic oil tank, and is connected to the pneumatic port b on the upper cover of the housing via pipeline. Static observation shows that all components and pipeline connections of the hydraulic system are correct and there is no oil leakage or abnormality, confirming that the hydraulic system is ready for start-up and commissioning; operate the cut-off solenoid valve to energize and maintain it, and observe the pressure rise and change of pressure gauge 2; initially open the throttle valve to 20±10%; confirm that there are no abnormalities in the pressurized hydraulic oil tank;

[0018] S32. Start the hydraulic system and observe the rise and fall of the pointer on pressure gauge 2 at the moment of start-up. Increase the opening of the throttle valve by 20±10%, stop the machine, unscrew the air filter cover to depressurize the housing, and then reinstall the air filter. Operate the cut-off solenoid valve again to energize and maintain it, start the hydraulic system, and observe the rise and fall of the pointer on pressure gauge 2 at the moment of start-up.

[0019] S33. Repeat step S32 M times, where M≥3. When the flow rate corresponding to the throttle valve opening is equal to q, the pointer of pressure gauge 2 swings within 15±5% of the total range during startup, indicating the throttle valve opening is properly adjusted. During the repeated S32 process, if it is found that the pressurized flow rate corresponding to the set throttle valve opening causes vibration and abnormal noise in the hydraulic system at startup, and the oil tank shows a tendency to bulge and deform, reduce the throttle valve opening by 20±10%.

[0020] S4. System Performance Verification: Simulate normal system operation by repeatedly starting and stopping the system. Observe and confirm that the housing has no obvious bulging or deformation, the oil pump operates normally, and there is no oil leakage, abnormal noise, or temperature rise. This confirms that the system is operating normally. If bulging or deformation of the housing occurs, pressurization and testing of the housing should be stopped immediately. For housings with obvious deformation or bulging, the welds should be inspected to confirm that there are no weld cracks or leaks. The bulging parts should be returned to the factory for leveling. At the same time, the internal rigidity of the housing should be strengthened by adding stiffening plates before installation. The pressurization control valve assembly should be disassembled and recalibrated on a hydraulic test bench before installation and pressurization testing. If the oil pump has oil leakage, abnormal noise, or a significant increase in housing temperature, the throttle valve opening setting should be appropriately reduced, the pressure reducing valve pressure setting should be lowered, the oil pump should be repaired or replaced, and the system should be reinstalled and tested.

[0021] S5. Confirm that the inspection is qualified.

[0022] When the shut-off solenoid valve is energized and held, the entire pneumatic circuit is open. High-pressure air from the air pressure system enters the housing through pneumatic interface b, and the air pressure inside the housing increases accordingly. When the air pressure reaches and exceeds the exhaust pressure of the air filter, the air filter exhausts and maintains stable internal pressure in the housing. The hydraulic system starts working. When the hydraulic system is running stably, the shut-off solenoid valve is de-energized and held, and the pneumatic circuit is cut off. Because the check valve is one-way shut off, the internal pressure fluctuations of the housing will not affect the working performance of the air pressure system. Repeatedly start and stop the hydraulic system several times and observe that the pressure of the air pressure system does not fluctuate. If the hydraulic system is running well, it is confirmed that the working performance of the pressurized hydraulic oil tank is qualified.

[0023] In step S33, the solenoid valve is controlled to remain energized or de-energized for a duration t, where t ≥ T. For example, if t = T + 5, after the pressure is applied to the desired level, the solenoid valve is controlled to remain energized for approximately 5 minutes.

[0024] An air filter installed on the top cover is an air filtration and cleaning device that allows air to freely enter a closed chamber after passing through the filter screen, but requires the passage to automatically open under rated internal air pressure to exit the chamber. The rated internal air pressure is determined by the pre-compression spring force of the air filter, and a pressure rating of 0.035MPa or 0.07MPa is generally selected. The air supply port a of the air pressure control valve group is connected to the high-pressure air from the air pressure system. The high-pressure air from the air pressure system is flow-limited by a throttle valve and then passes through the filter. The air filter is cleaned and controlled by the on / off switch of the solenoid valve. The air supply pressure is monitored by a pressure gauge. The high-pressure air is reduced by a pressure reducing valve. After passing through a check valve, the reduced air supply pressure is monitored by a pressure gauge. The air is then connected to the air pressure port b on the top cover of the housing via a pipeline to pressurize the air supply inside the housing. When the air pressure inside the housing reaches and exceeds the rated exhaust pressure of the air filter, the housing exhausts air to the outside at the exhaust pressure of the air filter. At the same time, the air pressure inside the housing is maintained at the rated exhaust pressure value of the air filter, thus having a pressurization function higher than atmospheric pressure.

[0025] The on / off control of the shut-off solenoid valve on the pneumatic pressure control valve assembly is determined based on the operating conditions of the hydraulic system. Operating conditions refer to the working conditions of the hydraulic system. For example, in a railcar primarily used for drive and cooling, the system runs continuously after the engine is started. In this case, pressurization can be performed in the initial stage before startup. After pressurization lasts for a few minutes, power is deactivated to stop pressurization, and the hydraulic system starts operating. For hydraulic systems with working devices performing construction operations, due to the intermittent nature of the mechanism's movements, a pressurization and pressure holding time can be set. When the mechanism's movement stops for more than the set time, the system automatically performs pressurization, which continues for a few minutes before power is deactivated to stop pressurization. Specific control strategies can be adjusted to match different vehicle configurations.

[0026] The pneumatic pressure control valve assembly includes a throttle valve, a filter, a shut-off solenoid valve, a pressure gauge one, a pressure reducing valve, a check valve, and a pressure gauge two, which are installed sequentially on the pipeline. The rear end of the pipeline is connected to the pneumatic interface b on the top of the housing, and the front end of the pipeline is the air supply port a.

[0027] The air filter installed on the top cover is an air filtration and cleaning device that allows air to freely enter the sealed enclosure through the filter screen, but requires automatic opening of the channel under rated internal air pressure to discharge from the enclosure. The air pressure control valve group's air supply port is connected to the high-pressure air from the air pressure system. The air passes through a throttle valve, filter, shut-off solenoid valve, pressure gauge, pressure reducing valve, check valve, and pressure gauge, and is connected via pipeline to the air pressure interface on the top of the enclosure. The high-pressure air from the air pressure system is flow-limited by the throttle valve, then filtered cleanly by the filter, and finally shut off... The on / off control of the solenoid valve uses a pressure gauge to monitor the supply air pressure. The high-pressure air is reduced by a pressure reducing valve, and after passing through a check valve, the reduced supply air pressure is monitored by a pressure gauge. The air is then connected to the air pressure port on the top of the housing via a pipeline to pressurize the air supply inside the housing. When the air pressure inside the housing reaches and exceeds the rated exhaust pressure of the air filter, the housing exhausts air to the outside at the exhaust pressure of the air filter. At the same time, the air pressure inside the housing is maintained at the rated exhaust pressure value of the air filter, thus providing a pressurization function that is higher than atmospheric pressure.

[0028] The on / off control of the shut-off solenoid valve on the pneumatic pressure control valve assembly is determined according to the operating conditions of the hydraulic system. When the hydraulic system starts working, the shut-off solenoid valve is energized and held, and the entire pneumatic circuit is open. High-pressure air from the air pressure system enters the housing through the pneumatic interface, and the air pressure inside the housing increases accordingly. When the air pressure reaches and exceeds the exhaust pressure of the air filter, the air filter exhausts and keeps the housing pressurized and stable. When the hydraulic system is working stably, the shut-off solenoid valve is de-energized and held, and the pneumatic circuit is cut off. Because the check valve is one-way shut off, the internal pressure fluctuation of the housing will not affect the working performance of the air pressure system in the reverse direction.

[0029] This invention employs a bottom-mounted support system for the tank, ensuring stability and reliability. A horizontal partition, bolted to the center of the tank, divides the tank into upper and lower sections: a return oil chamber and a suction oil chamber. The distance between the partition and the inner wall of the tank forms a vertical channel connecting the return and suction chambers. The returning oil, guided by the partition, automatically forms a vortex flow characteristic, promoting oil circulation, heat dissipation, and the release and defoaming of mixed air bubbles. It also prevents floating foam generated during return from entering the suction chamber and being directly sucked into the oil pump. The partition's central position also enhances the overall rigidity of the tank, reducing the likelihood of bulging in the center due to pressure. For high-altitude equipment with more compact structures and maintenance spaces, the return oil filter is suspended externally, while the suction filter is mounted on the side, facilitating filter element maintenance and replacement and reducing the required maintenance space for the hydraulic oil tank. The hydraulic oil tank of this invention has a compact structure, is easy to transport, can be designed to be small in size, and has strong versatility. It can be widely used in the field of engineering machinery, especially in rail vehicles and railway engineering machinery.

[0030] Using this invention, while applying pressure, the hydraulic system's oil pump is ensured to draw oil safely and reliably, and the hydraulic oil tank structure is protected from significant deformation. In engineering practice, the oil pump's suction pressure should generally be less than 1 MPa. Excessive suction pressure can cause the pump seals to be squeezed out, or even the pump housing to burst; excessive pressure can also cause the hydraulic oil tank to bulge and deform, or even the welds to crack. Attached Figure Description

[0031] Figure 1 This is the front view of the present invention;

[0032] Figure 2 This is the left view of the present invention;

[0033] Figure 3 This is a system schematic diagram of the present invention;

[0034] In the diagram: 1. Return oil filter; 2. Return oil pipe; 2-1. Return oil line; 3. Lifting lug; 4. Housing; 5. Top cover; 6. Air filter; 7. Air pressure control valve assembly; 7. Throttle valve; 7-1. Filter; 7-2. Shut-off solenoid valve; 7-3. Pressure reducing valve; 7-4. Pressure gauge; 7-5. Check valve; 7-6. Pressure gauge; 7-7. Level gauge; 8. Drain port assembly; 9. Drain line; 9-1. Horizontal partition; 10. Threaded seat; 11. Oil drain port; 12. Mounting seat; 13. Suction filter; 14. Suction filter cartridge; 14-1. Air supply port a; Air pressure interface b; Return oil interface c. Detailed Implementation

[0035] The present invention will be further described in detail below with reference to the accompanying drawings. These embodiments are only used to explain the present invention and do not constitute a limitation on the scope of protection of the present invention.

[0036] like Figure 1 , Figure 2As shown, the hydraulic oil tank is mounted on a bottom mounting base 13 and includes a rectangular box body 4, a top cover plate 5, an air filter 6, a pneumatic pressure control valve assembly 7, a level gauge 8, an oil drain assembly 9, a transverse partition 10, a threaded seat 11, an oil drain port 12, a mounting base 13, and an oil suction filter 14. The box body 4 is a rectangular enclosed box body assembled by welding left, right, front, and rear upright plates to a bottom plate, and then using bolts and sealing gaskets to connect the top cover plate 5. The partition 10 divides the entire inner cavity of the tank 4 into upper and lower parts: the oil return chamber and the oil suction chamber. The distance between the partition 10 and the inner wall of the tank 4 forms an upper and lower channel for connecting the oil return chamber and the oil suction chamber. The oil return filter 1 is suspended and installed on the outside of the tank 4, and is inserted into the oil return chamber of the tank 4 through the oil return pipe 2 and the oil return pipeline 2-1. The end of the oil return pipeline 2-1 is beveled. The oil suction filter 14 is installed on the side of the tank 4, and the oil suction filter cartridge 14-1 is inserted into the oil suction chamber. A level gauge 8 is installed on the right outer wall of the tank 4 with a recessed mounting plate. The outer wall of the housing 4 is provided with several drain port assemblies 9 for connecting the drain pipes in the hydraulic system. The drain port assemblies 9 are connected to the return oil chamber of the housing 4 through drain pipes 9-1. The end of the drain pipes 9-1 is beveled. The left and right outer walls of the housing 4 are provided with lifting lugs 3. The left and right sides of the bottom plate of the housing 4 are provided with mounting seats 13. The front outer wall of the housing 4 is provided with threaded seats 11 for installing level sensors, temperature sensors, pressure sensors and oil sampling valves. The bottom right side of the housing 4 is provided with an oil drain port 12 for draining oil from the hydraulic oil tank. The oil drain port 12 is sealed with a plug.

[0037] like Figure 3 As shown, an air pressure control valve assembly 7 is installed outside the housing 4. The air pressure control valve assembly 7 includes an air supply port a, a throttle valve 7-1, a filter 7-2, a shut-off solenoid valve 7-3, a pressure gauge 7-5, a pressure reducing valve 7-4, a check valve 7-6, and a pressure gauge 7-7 connected in sequence and connected to the air pressure interface b on the top of the housing 4 through a pipeline. An air filter 6 is provided on the upper cover plate 5. The air filter 6 is an air filtration and cleaning device that allows air to freely enter the closed housing 4 through the filter screen, but requires the channel to be automatically opened under the rated internal air pressure to be discharged from the housing 4. One end of the drain pipe in the hydraulic system is connected to the drain port assembly 9, and the other end is connected to the oil supply port of the hydraulic system drain port. One end of the return pipe in the hydraulic system is connected to the return port c, and the other end is connected to the oil supply port of the hydraulic system return port. One end of the suction pipe in the hydraulic system is connected to the suction port d, and the other end is connected to the oil supply port of the hydraulic system oil pump suction pump.

[0038] like Figure 3As shown, in practical applications, the air supply port a of the air pressure control valve group 7 is connected to the high-pressure air from the air pressure system. The flow is limited by the throttle valve 7-1, then filtered clean by the filter 7-2, and controlled by the on / off control of the shut-off solenoid valve 7-3. The air supply pressure is monitored by the pressure gauge 7-5. The high-pressure air is reduced by the pressure reducing valve 7-4, and after passing through the check valve 7-6, the reduced air supply pressure is monitored by the pressure gauge 7-7. The air is then connected to the air pressure port b on the top of the housing 4 via a pipeline to pressurize the air supply inside the housing 4. When the air pressure inside the housing 4 reaches and exceeds the rated exhaust pressure of the air filter 6, the housing 4 exhausts air to the outside at the exhaust pressure of the air filter 6. At the same time, the air pressure inside the housing 4 is maintained at the rated exhaust pressure value of the air filter 6, thus having a pressurization function higher than atmospheric pressure.

[0039] The on / off control of the shut-off solenoid valve 7-3 is determined according to the operating conditions of the hydraulic system. When the hydraulic system starts working, the shut-off solenoid valve 7-3 is energized and maintained, and the entire pneumatic circuit is open. High-pressure air from the air pressure system enters the housing 4 through the air pressure interface b, and the internal air pressure of the housing increases accordingly. When the air pressure reaches and exceeds the exhaust pressure of the air filter 6, the air filter 6 exhausts and maintains the pressure of the housing 4 stable. When the hydraulic system is working stably, the shut-off solenoid valve 7-3 is de-energized and maintained, and the pneumatic circuit is cut off. Because the one-way valve 7-6 is one-way shut off, the internal pressure fluctuation of the housing 4 will not affect the working performance of the air pressure system in the reverse direction.

[0040] In practical applications, the return oil in the system enters the return oil filter 1 through the return oil interface c, and after being filtered, it returns to the return oil chamber of the housing 4 through the return oil pipe 2-1. The returned oil is guided by the transverse baffle 10, which automatically forms a vortex oil flow characteristic, so that the oil in the housing circulates and dissipates heat and releases and defoams mixed with air bubbles. It can also prevent the floating foam generated by the return oil from entering the oil suction chamber and being directly sucked in by the oil pump. The transverse baffle is set in the middle position inside the housing, which also helps to improve the overall rigidity of the housing.

[0041] For high-altitude, low-pressure environments, the preferred design for the transverse partition 10 is rectangular, or a perforated rectangular or polygonal shape, depending on the oil circulation requirements. It is positioned in the center of the inner cavity of the housing 4 and fixed to a welded support on the inner wall of the housing 4 with bolts. A gap or spacing exists between the transverse partition 10 and the inner wall of the housing 4 to form a flow channel for oil circulation. Simultaneously, the support provided by the transverse partition 10 increases the overall rigidity of the housing 4, reducing the amount of bulging deformation in the center of the housing caused by internal pressurization. Preferably, the return oil filter is suspended externally on the housing, while the suction oil filter is installed on the side of the housing. This facilitates filter element inspection and replacement, reducing the space requirements for installation and maintenance of the hydraulic oil tank on the entire machine.

[0042] The preferred pneumatic pressure control valve assembly 7 includes components such as a throttle valve 7-1, a filter 7-2, a shut-off solenoid valve 7-3, a pressure reducing valve 7-4, a pressure gauge 7-5, a check valve 7-6, and a pressure gauge 7-7, all made of stainless steel or copper. The number of components in the pneumatic pressure control valve assembly 7 can be increased or decreased according to pressure control needs. The preferred shut-off solenoid valve 7-3 is a solenoid directional valve that allows bidirectional flow when energized and bidirectional shut-off when de-energized.

[0043] A method for controlling the pressure of a pressurized hydraulic oil tank includes the following steps:

[0044] S1, Connection of the hydraulic system

[0045] One end of the drain pipe in the hydraulic system is connected to the drain port assembly 9 on the outer wall of the return oil chamber of the hydraulic oil tank 4, and the other end is connected to the oil supply port of the hydraulic system. One end of the return oil pipe in the hydraulic system is connected to the return oil interface c on the return oil filter 1 installed outside the tank 4, and the other end is connected to the oil supply port of the hydraulic system. One end of the suction pipe in the hydraulic system is connected to the suction port d, and the other end is connected to the oil pump suction port of the hydraulic system to supply oil to the pump. This allows the hydraulic oil tank to be connected to the hydraulic system, forming a complete circulation loop system.

[0046] S2. Calibration of initial parameters

[0047] Install the pneumatic pressure control valve assembly 7 on the hydraulic test bench and apply pressure and flow. Based on the preset pressure value A of the air filter 6 and the maximum pressure value C that the chamber can withstand, determine the pressure target value B of the pressure reducing valve 7-4, where C > A ≥ B. Adjust the opening of the throttle valve 7-1 to the minimum state. The preset pressure value A of the air filter 6 on the upper cover plate 5 is determined in the initial design stage based on the actual operating environment of the hydraulic system. A = chamber pressure value.

[0048] S3, Installation parameter settings

[0049] Based on the volume V of the housing, the pressurization time T, and the target pressurization value B, calculate the flow rate q corresponding to the opening degree that the throttle valve needs to be set, where q = αBV / T, and α is a calculation constant.

[0050] S31. The pneumatic control valve group 7 is installed outside the housing 4 to form a pressurized hydraulic oil tank, and is connected to the pneumatic port b of the upper cover plate 5 of the housing 4 through a pipeline. Static observation shows that the hydraulic system components and pipeline connections are correct and there is no oil leakage or abnormality, confirming that the hydraulic system is ready for start-up and commissioning. Operate the cut-off solenoid valve 7-3 to be energized and maintain it, and observe the pressure rise and change of pressure gauge 7-7. Initially increase the opening of the throttle valve 7-1 by 20±10%; confirm that there are no abnormalities in the pressurized hydraulic oil tank.

[0051] S32. Start the hydraulic system and observe the pointer of pressure gauge 7-7 swinging up and down at the moment the hydraulic system starts. Increase the opening of throttle valve 7-1 by 20±10%, stop the machine, unscrew the top cover of air filter 6 to depressurize the housing, and then reinstall the air filter. Operate the cut-off solenoid valve 7-3 again to energize and maintain it, start the hydraulic system, and observe the pointer of pressure gauge 7-7 swinging up and down at the moment the hydraulic system starts.

[0052] S33. Repeat step S32 M times, where M≥3. When the flow rate corresponding to the throttle valve opening is equal to q, the pointer of pressure gauge 7-7 swings within 15±5% of the total range during startup, indicating that the throttle valve opening is properly adjusted. During the repeated steps of S32, if it is found that the pressurized flow rate corresponding to the set throttle valve opening causes vibration and abnormal noise in the hydraulic system at startup, and the oil tank shows a tendency to bulge and deform, reduce the opening of throttle valve 7-1 by 20±10% (i.e., 1-2 turns).

[0053] S4. System performance test: Simulate the normal operating conditions of the system and start and stop the system multiple times. Observe and confirm that there is no obvious bulging or deformation of the housing 4, the oil pump is running normally, and there is no oil leakage, abnormal noise or temperature rise. This confirms that the system is operating normally.

[0054] S5. Confirm that the inspection is qualified.

[0055] When the shut-off solenoid valve 7-3 is energized and held, the entire pneumatic circuit is open. High-pressure air from the air pressure system enters the housing 4 through the pneumatic port b, and the air pressure inside the housing increases accordingly. When the air pressure reaches and exceeds the exhaust pressure of the air filter 6, the air filter 6 exhausts and maintains stable pressure inside the housing 4. The hydraulic system starts working. When the hydraulic system is running stably, the shut-off solenoid valve 7-3 is de-energized and held, and the pneumatic circuit is cut off. Because the one-way valve 7-6 is one-way shut off, the pressure fluctuation inside the housing 4 will not affect the working performance of the air pressure system in the reverse direction. The hydraulic system is started and stopped several times. If the pressure of the air pressure system does not fluctuate and the hydraulic system is running well, it is confirmed that the working performance of the pressurized hydraulic oil tank is qualified.

[0056] Before actual system commissioning, the pressure reducing valve 7-4 was calibrated to 0.03 MPa using a hydraulic test bench, and the opening of the throttle valve 7-1 was adjusted to its minimum. During actual system commissioning, the shut-off solenoid valve 7-3 was energized and held, and the pressure rise and change of the pressure gauge 7-7 were observed. Based on the size of the tank 4, the opening of the throttle valve 7-1 was adjusted appropriately to control the rate of system inflation. The hydraulic system was started, and the pressure change of the pressure gauge 7-7 was observed. The opening of the throttle valve 7-1 and the pressure setting of the pressure reducing valve 7-4 were adjusted appropriately, controlling the duration of energization or de-energization of the shut-off solenoid valve 7-3. The hydraulic system was run for at least one hour under working conditions. It was confirmed that the tank 4 had no obvious bulging or deformation, the oil pump was operating normally, and there was no oil leakage, abnormal noise, or temperature rise, thus optimizing the pressurization control strategy. By implementing a reasonable pressurization control strategy, it is possible to avoid instantaneous cracking of the hydraulic oil tank or bursting of the hydraulic pump housing due to excessively short inflation and pressurization times. It can also avoid alternating pressure from alternating air pressurization or oil pump start-up and oil suction pressure reduction, which can lead to structural changes in the hydraulic oil tank and pressure fluctuations in the hydraulic system, thus affecting the safe operation of the hydraulic system.

[0057] In practical applications, considering the frequency of hydraulic system starts and stops, for hydraulic systems that start frequently, the opening of throttle valve 7-1 should be appropriately reduced to avoid pressure surges caused by frequent starts. Starting more than 3 times per hour is generally considered frequent starting, and starting 10 times per workday can be considered regular starting; in such cases, the opening should be reduced by 20-50%. For hydraulic systems that operate continuously after a single start, the opening of throttle valve 7-1 should be appropriately increased to improve operational efficiency while ensuring system safety and reliability.

[0058] The above description, taken in conjunction with the accompanying drawings, is merely a description of one specific embodiment of the present invention and does not limit the technical solution of the present invention to this. All equivalent changes or modifications to the appearance made in accordance with the spirit and essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A pressurized hydraulic oil tank, characterized in that: The enclosure includes a closed housing (4). A partition (10) divides the interior of the housing (4) into two parts: an oil return chamber and an oil suction chamber. The partition (10) and the inner wall of the housing (4) form an upper and lower channel, which connects the oil return chamber and the oil suction chamber. The oil return filter (1) is suspended on the outside of the housing (4) and inserted into the oil return chamber of the housing (4) through the oil return pipe (2) and the oil return pipeline (2-1). The oil suction filter (14) is installed on the side of the housing (4). The oil suction filter cartridge (14-1) is inserted into the oil suction chamber. The air pressure control... The control valve assembly (7) is installed outside the housing (4) and connected to the air pressure port (b) of the upper cover plate (5) of the housing (4) through a pipeline; the air pressure control valve assembly (7) is installed outside the housing (4), and the air pressure control valve assembly (7) includes an air supply port (a), a throttle valve (7-1), a filter (7-2), a shut-off solenoid valve (7-3), a pressure gauge (7-5), a pressure reducing valve (7-4), a one-way valve (7-6), and a pressure gauge (7-7) connected in sequence and connected to the air pressure port (b) at the top of the housing (4) through a pipeline.

2. The pressurized hydraulic oil tank according to claim 1, characterized in that: The diaphragm (10) is fixedly installed in the middle of the box (4) by bolts, dividing the box (4) into two parts: the oil return chamber and the oil suction chamber. The length and width of the diaphragm (10) are smaller than the length and width of the inner cavity of the box (4). An air filter (6) is provided on the upper cover plate (5).

3. The pressurized hydraulic oil tank according to claim 1, characterized in that: The outer wall of the return oil chamber of the housing (4) is provided with several drain port assemblies (9) for connecting the drain pipe in the hydraulic system. The drain port assembly (9) is connected to the return oil chamber inserted into the housing (4) through the drain pipe (9-1). The end of the drain pipe (9-1) is a beveled surface.

4. The pressurized hydraulic oil tank according to claim 1, characterized in that: The oil suction filter cartridge (14-1) of the oil suction filter (14) is inserted into the oil return chamber of the housing (4). The oil return filter (1) installed outside the housing (4) is connected to the oil return chamber inserted into the housing (4) via the oil return pipe (2) and the oil return pipeline (2-1). The end of the oil return pipeline (2-1) is a beveled surface.

5. The pressurized hydraulic oil tank according to claim 1, characterized in that: The enclosed box (4) is a rectangular structure assembled by welding the left, right, front and rear uprights to the bottom plate, and then by bolting the top cover (5) with a sealing gasket.

6. The pressurized hydraulic oil tank according to claim 1, characterized in that: The return oil chamber is provided with a level gauge (8) installed on the right outer side wall of the box (4) with a concave mounting plate; the left and right outer side walls of the box (4) are provided with lifting lugs (3); the bottom plate of the box (4) is provided with mounting seats (13) on the left and right sides; the front outer side wall of the box (4) is provided with a number of threaded seats (11); the bottom right side of the box (4) is provided with an oil drain port (12); the oil drain port (12) is sealed with a plug.

7. A method for controlling the pressure of a pressurized hydraulic oil tank, characterized in that: The steps include the following: S1, Connection of the hydraulic system One end of the drain pipe in the hydraulic system is connected to the drain port assembly (9) on the outer wall of the return oil chamber of the hydraulic oil tank (4), and the other end is connected to the oil supply port of the hydraulic system. One end of the return oil pipe in the hydraulic system is connected to the return oil interface (c) on the return oil filter (1) installed outside the tank (4), and the other end is connected to the oil supply port of the hydraulic system. One end of the suction pipe in the hydraulic system is connected to the suction port (d), and the other end is connected to the oil pump suction port of the hydraulic system to supply the oil pump to suction oil; so that the hydraulic oil tank is connected to the hydraulic system to form a complete circulation loop system. S2. Calibration of initial parameters Install the air pressure control valve group (7) on the hydraulic test bench to apply pressure and flow. Based on the preset pressure value A of the air filter (6) and the maximum value C that the box can withstand, determine the pressure target value B of the pressure reducing valve 7-4, C>A≥B; adjust the opening of the throttle valve (7-1) to the minimum state. The preset pressure value A of the air filter (6) on the upper cover plate (5) is determined in the initial stage of design based on the actual operating environment of the hydraulic system. A=box pressure value. S3, Installation parameter settings Based on the volume V of the housing, the pressurization time T, and the target pressurization value B, calculate the flow rate q corresponding to the opening degree that the throttle valve needs to be set, where q = αBV / T, and α is a calculation constant. S31. The pneumatic pressure control valve group (7) is installed outside the housing (4) to form a pressurized hydraulic oil tank, and is connected to the pneumatic port (b) of the upper cover plate (5) of the housing (4) through a pipeline. Observe the hydraulic system components and pipeline connections to ensure they are correct and there is no oil leakage. Confirm that the hydraulic system is ready for start-up and commissioning. Operate the cut-off solenoid valve (7-3) to be energized and maintain it, and observe the pressure rise and change of pressure gauge 2 (7-7). Initially increase the opening of the throttle valve (7-1) by 20±10%. Confirm that there are no abnormalities in the pressurized hydraulic oil tank. S32. Start the hydraulic system and observe the pointer swing of pressure gauge 2 (7-7) at the moment of hydraulic system startup. Increase the opening of throttle valve (7-1) by 20±10%, stop the machine, unscrew the top cover of air filter (6), depressurize the housing, and then reinstall the air filter. Operate the cut-off solenoid valve (7-3) again to energize and maintain it, start the hydraulic system, and observe the pointer swing of pressure gauge 2 (7-7) at the moment of hydraulic system startup. S33. Repeat step S32 M times, where M≥3. When the flow rate corresponding to the throttle valve opening is equal to q, the pointer swing range of pressure gauge 2 (7-7) during startup is within 15±5% of the total range, indicating that the throttle valve opening is properly adjusted. During the repeated steps of S32, if it is found that the pressurized flow rate corresponding to the set throttle valve opening causes vibration and abnormal noise in the hydraulic system at startup, and the oil tank shows a tendency to bulge and deform, reduce the opening of throttle valve 7-1 by 20±10%. S4. System performance test: Simulate the normal operating conditions of the system and start and stop the system multiple times. Observe and confirm that there is no obvious bulging or deformation of the housing 4, the oil pump is running normally, and there is no oil leakage, abnormal noise or temperature rise. This confirms that the system is operating normally. S5. Confirm that the inspection is qualified. When the shut-off solenoid valve (7-3) is energized and held, the entire pneumatic circuit is open. High-pressure air from the air pressure system enters the housing (4) through the pneumatic interface (b), and the air pressure inside the housing increases accordingly. When the air pressure reaches and exceeds the exhaust pressure of the air filter (6), the air filter (6) exhausts and keeps the internal pressure of the housing (4) stable. The hydraulic system starts working. When the hydraulic system is running stably, the shut-off solenoid valve (7-3) is de-energized and held, and the pneumatic circuit is cut off. Because the check valve (7-6) is cut off in one direction, the internal pressure fluctuation of the housing (4) will not affect the working performance of the air pressure system in the reverse direction. The hydraulic system is started and stopped several times. The pressure of the air pressure system is observed to be stable. The hydraulic system is running well, which confirms that the working performance of the pressurized hydraulic oil tank is qualified.

8. The pressure control method for a pressurized hydraulic oil tank according to claim 7, characterized in that: In step S33, the solenoid valve (7-3) is controlled to remain energized or de-energized for a time t, where t ≥ T.

9. The pressure control method for a pressurized hydraulic oil tank according to claim 7, characterized in that: An air filter (6) is installed on the top cover plate (5). It is an air filtration and cleaning device that allows air to freely enter the closed box (4) through the filter screen, but requires the passage to be automatically opened under rated internal air pressure before it can be discharged from the box (4). The air supply port (a) of the air pressure control valve group (7) is connected to the high-pressure air from the air pressure system. The high-pressure air from the air pressure system is limited by the flow rate of the throttle valve (7-1), then filtered clean by the filter (7-2), and controlled by the on / off state of the shut-off solenoid valve (7-3). The pressure gauge (7-5) is used for pressure measurement. The air supply pressure is monitored by reducing the pressure of the incoming high-pressure air through the pressure reducing valve (7-4), and then through the check valve (7-6). The pressure is monitored by the pressure gauge (7-7). The air supply pressure is connected to the air pressure port (b) of the top cover plate (5) of the box (4) through the pipeline to pressurize the air supply inside the box (4). When the air pressure inside the box (4) reaches and exceeds the rated exhaust pressure of the air filter (6), the box (4) exhausts the air to the outside at the exhaust pressure of the air filter (6). At the same time, the air pressure inside the box (4) is maintained at the rated exhaust pressure value of the air filter (6), thus having a pressurization function higher than atmospheric pressure. The on / off control of the shut-off solenoid valve (7-3) on the pneumatic pressure control valve group (7) is determined according to the operating conditions of the hydraulic system.

10. The pressure control method for a pressurized hydraulic oil tank according to claim 9, characterized in that: The air pressure control valve group (7) includes a throttle valve (7-1), a filter (7-2), a shut-off solenoid valve (7-3), an air pressure gauge (7-5), a pressure reducing valve (7-4), a check valve (7-6), and an air pressure gauge (7-7) installed sequentially on the pipeline. The rear end of the pipeline is connected to the air pressure interface (b) on the top of the box (4), and the front end of the pipeline is the air supply port (a).

Images