Integrated built-in safety valve

Abstract

The utility model discloses an integrated built-in safety valve, belongs to the field of metering pumps, and aims to solve the problems that in the prior art, a non-integrated structure is not convenient to disassemble, assemble and maintain, a main sealing line is arranged on a hydraulic cylinder, a hydraulic cylinder orifice is high in machining difficulty, out-of-round sealing is prone to failure, consequently, the hydraulic cylinder is scrapped, an upper limiting part is complex in structure, a pressure adjusting spring is inconvenient to adjust, and the like. And the installation occasion is limited. The check valve comprises a valve seat, the valve seat is composed of an upper cylinder and a lower cylinder, a valve body is sleeved outside the upper cylinder, a main valve core is arranged above the valve seat, and a first channel and a second channel are arranged in the valve seat. The integrated structure is convenient to disassemble, assemble and maintain; the lower end conical surface of the main valve core is in line contact with the opening of the valve seat, and the main sealing line is arranged on the valve seat, so that the hydraulic cylinder is prevented from being scrapped due to out-of-round orifice; spring seats and adjusting holes are respectively arranged at two ends of the adjusting screws in the thread grooves, so that the adjustment is convenient; the oil plug is in threaded fit with the top opening of the valve body and provided with a sealing gasket, the structure is simple, and the installation occasion is wider.

Description

Technical Field

[0001] The utility model relates to the field of metering pumps, and more specifically, it relates to an integrated built-in safety valve. Background Art

[0002] The performance of a three-valve hydraulic diaphragm metering pump depends to a large extent on the coordination ability of the three-valve group. The three-valve group includes a compensation valve, a vent valve, and a hydraulic chamber safety valve. Among them, the compensation valve is used to control the replenishment of hydraulic oil in the hydraulic cylinder, the vent valve is used to exhaust the excess gas in the hydraulic cylinder to ensure that the hydraulic oil is filled sufficiently, and the hydraulic chamber safety valve is used for overpressure overflow to protect the metering pump.

[0003] The existing hydraulic chamber safety valve has a non-integrated structure, and its internal parts are not completely encapsulated in the valve body, which is not convenient for installation, disassembly, and maintenance. The spool of the existing hydraulic chamber safety valve is in direct line contact with the orifice of the hydraulic cylinder for sealing, which is the key to ensuring that the hydraulic oil does not leak under normal conditions and preventing air from flowing back during the suction stroke of the plunger. Therefore, the processing accuracy is very high. That is, in addition to maintaining a necessary cutting edge at the outlet, the roundness requirement of the orifice is also relatively high; and the hydraulic cylinder is a key component at the hydraulic end of the hydraulic diaphragm metering pump, with many internal flow channels that are crisscrossed, and the structure is very complex, with high processing difficulty and time-consuming; in practical applications, it is found that due to the processing accuracy problem of the orifice of the hydraulic cylinder, the orifice becomes out-of-round, resulting in seal failure, which is very common, and the effect of secondary repair is not ideal, causing the hydraulic cylinder to be scrapped, resulting in a large economic loss. The existing hydraulic chamber safety valve adopts an external oil return pipeline, which is not compact and beautiful in structure, and the oil return pipeline usually uses a plastic hose, which is particularly prone to aging and failure under the influence of weather and external environment, resulting in hydraulic oil leakage. The limiting part above the existing hydraulic chamber safety valve has a relatively complex structure, the pressure regulating spring is not convenient to adjust, and the height of the part of the limiting part outside the valve body is too large, resulting in limited installation occasions. The existing hydraulic chamber safety valve has no self-exhaust function. For medium and small flow pumps, it is not easy to ensure the volumetric efficiency. To meet the exhaust function, an exhaust valve needs to be separately provided on the hydraulic cylinder, with a complex structure and inconvenient application.

[0004] Chinese Patent Publication No. CN218543298U, publication date February 28, 2023, the name of the utility model is a metal-coupled high-pressure safety valve structure. This application discloses a metal-coupled high-pressure safety valve structure, which includes a valve body and a valve seat. The valve body is threadedly connected above the hydraulic cylinder body through external threads provided on the outer side of the lower end, and an inner cavity is opened inside the valve body; the valve seat is arranged inside the inner cavity, and at least part of the valve seat protrudes from the lower end face of the valve body and blocks the communication hole between the pressure oil cavity and the inner cavity. An elastic reset member is abutted above the valve seat, and a limiting portion is abutted above the elastic reset member; a fluid passage is opened in the valve seat, and a valve core is arranged in the fluid passage. The valve core is coupled with the valve seat, and a fluid permeation gap is formed between the valve core and the inner wall of the valve seat. The metal-coupled high-pressure safety valve structure disclosed in the above patent document adopts an internal oil return pipeline, and the structure is relatively compact and beautiful, avoiding the problem that the plastic hose of the external oil return pipeline is particularly prone to aging and failure under the influence of weather and external environment, resulting in hydraulic oil leakage. And it adopts an exhaust flow passage with multiple steps composed of a valve ball, a valve core and a valve cover, and has an independent exhaust function; however, it is not an integral structure, which is not convenient for installation, disassembly and maintenance. The main seal line is set on the hydraulic cylinder, and the processing of the hydraulic cylinder orifice is difficult and time-consuming, and it is easy for the orifice to be out of round, resulting in seal failure and scrapping of the hydraulic cylinder. The limiting portion above it has a relatively complex structure, the adjustment of the pressure regulating spring is not convenient, and the installation occasion is limited. Summary of the Invention

[0005] Aiming at the problems of the prior art mentioned in the background technology that it is not an integral structure, not convenient for installation, disassembly and maintenance, the main seal line is set on the hydraulic cylinder, the processing of the hydraulic cylinder orifice is difficult and time-consuming, it is easy for the orifice to be out of round, resulting in seal failure and scrapping of the hydraulic cylinder, the limiting portion above it has a relatively complex structure, the adjustment of the pressure regulating spring is not convenient, and the installation occasion is limited, the present utility model provides an integral internal safety valve. It adopts an integral structure in which the valve seat is sleeved with the valve body, which is convenient for later installation, disassembly and maintenance; it adopts a sealing structure in which the lower conical surface of the main valve core and the opening edge of the valve seat form a line contact, and the main seal line is not set on the hydraulic cylinder, avoiding the problem that the hydraulic cylinder is easy to be out of round at the orifice, resulting in seal failure and scrapping of the hydraulic cylinder, saving costs; it adopts a structure in which an internal adjusting screw is arranged on the threaded groove on the inner wall of the valve body, and a spring seat and an adjusting hole are respectively arranged at both ends of the internal adjusting screw, making the adjustment of the pressure regulating spring convenient. It adopts a structure in which the oil plug and the top opening of the valve body are threadedly matched and provided with a sealing gasket, making the limiting portion structure above the safety valve simpler and more compact and the installation occasion wider.

[0006] To solve the above technical problems, the present utility model adopts the following technical solutions: An integrated built-in safety valve, comprising: a valve seat, the valve seat is composed of an upper cylinder and a lower cylinder, the upper cylinder is sleeved with a valve body, a main valve core is arranged above the valve seat, and a first channel and a second channel are arranged in the valve seat. In the present utility model, the integrated structure with the valve body sleeved outside the valve seat is convenient for later installation, disassembly and maintenance; the sealing structure in which the lower conical surface of the main valve core and the opening edge of the valve seat form a line contact is adopted, and the main sealing line is not arranged on the hydraulic cylinder, avoiding the problem that the hydraulic cylinder is easily out-of-round at the orifice, resulting in seal failure and scrapping of the hydraulic cylinder, thus saving costs.

[0007] Preferably, the diameter of the upper cylinder is smaller than the diameter of the lower cylinder. With this design, the larger diameter of the lower cylinder provides a larger supporting area for the valve body sleeved outside the upper cylinder above, which helps to increase the overall stability of the built-in safety valve and reduce the risk of deformation under high-pressure working conditions.

[0008] Preferably, a sealing ring A is arranged at the mating surface of the upper cylinder and the valve body. This structure can not only prevent the hydraulic oil inside the safety valve body from leaking out and ensure its sealing performance, but also prevent the valve seat from disengaging from the valve body by virtue of the elastic characteristics of the sealing ring itself.

[0009] Preferably, a third channel is further arranged in the valve seat, a third channel port B is arranged above the third channel, and the third channel port B is a cylindrical groove. The third channel in the valve seat connects the hydraulic cylinder cavity and the valve body cavity above the valve seat. The third channel port B is designed as a cylindrical groove and is used in cooperation with the main valve core, thereby playing a main sealing role.

[0010] Preferably, the lower end of the main valve core is conical. The conical surface sealing structure formed by the cooperation of the lower conical surface of the main valve core and the third channel port B of the valve seat has a greater specific pressure and better sealing effect compared with the plane sealing structure. At the same time, the two parts do not need to be lapped, reducing the processing difficulty.

[0011] Preferably, the lower end of the main valve core and the opening edge of the third channel port B form a line contact. The sealing structure formed by this line contact has its main sealing line not arranged on the hydraulic cylinder, avoiding the problem that the hydraulic cylinder is easily out-of-round at the orifice, resulting in seal failure and unsatisfactory secondary repair effect, and causing the hydraulic cylinder to be scrapped, thus saving costs; the sealing structure formed by this line contact has its main sealing line arranged on the valve seat. If the valve seat has a problem of out-of-round orifice resulting in seal failure, the difficulty and cost of its repair and processing are relatively low.

[0012] Preferably, the first channel and the second channel are symmetrically arranged with respect to the third channel. Both the first channel and the second channel in the valve seat are part of the built-in oil return passage. The upper ends of the first channel and the second channel communicate with the inner cavity of the valve body above the valve seat, and the lower end of either the first channel or the second channel communicates with the part of the built-in oil return passage located within the hydraulic cylinder body. The dual-channel design of the first channel and the second channel in the valve seat can flexibly handle the situation where one of the channels fails, can adapt to more hydraulic cylinder bodies, and can also efficiently handle the situation where a large amount of hydraulic oil needs to be quickly released. The design that the first channel and the second channel in the valve seat are symmetrically arranged with respect to the third channel can ensure that the pressure distribution of the hydraulic oil when passing through the safety valve is more uniform, which helps to improve the stability and reliability of the entire system. At the same time, the symmetrical structure helps to optimize the hydrodynamic performance, reduce the fluid resistance, and thus improve the fluid flow efficiency. The design of the built-in oil return passage enables the overflow hydraulic oil to flow back to the fuel tank after passing through the internal channel, avoiding the external oil return pipeline. The structure is compact and beautiful, and at the same time, it can avoid the problem that the plastic hose of the external oil return pipeline is particularly prone to aging and failure due to weather and external environment, resulting in hydraulic oil leakage.

[0013] Preferably, the inner wall of the valve body is provided with a threaded groove, and an internal adjusting screw is provided on the threaded groove. In this structure, the threaded groove has a certain length, and the internal adjusting screw can rotate along the threaded groove to freely adjust its height position, which is convenient for adjustment.

[0014] Preferably, a pressure regulating spring is provided below the internal adjusting screw, a spring seat is provided at one end of the internal adjusting screw close to the pressure regulating spring, and an adjusting hole is provided at the other end. The structure in which the internal adjusting screw arranged on the threaded groove on the inner wall of the valve body is provided with a spring seat and an adjusting hole at both ends makes it convenient to adjust the pressure regulating spring. Among them, the spring seat at one end of the internal adjusting screw is used to stably arrange the pressure regulating spring, and the adjusting hole at the other end of the internal adjusting screw is used in combination with an internal hexagonal wrench for adjustment.

[0015] Preferably, the integrated built-in safety valve further includes an oil plug, the oil plug is arranged in the top opening of the valve body, and the oil plug and the valve body are in threaded fit and provided with a sealing gasket. The structure in which the oil plug and the top opening of the valve body are in threaded fit and provided with a sealing gasket makes the limiting part structure above the safety valve simpler and more compact. And the height of the part of the limiting part outside the valve body is smaller, so the installation occasion of the current safety valve is wider. In addition, this structure has better sealing effect, and is more convenient for installation and disassembly.

[0016] Compared with the prior art, the beneficial effects of the present utility model are as follows: (1) The integrated structure with the valve seat externally sleeved with the valve body facilitates later installation, disassembly, and maintenance; (2) The conical surface at the lower end of the main spool and the opening edge of the valve seat form a line-contact sealing structure, and the main sealing line is not arranged on the hydraulic cylinder, avoiding the problem that the hydraulic cylinder is prone to orifice out-of-roundness leading to seal failure and causing the hydraulic cylinder to be scrapped, thus saving costs; (3) The structure in which the inner adjusting screw arranged on the inner wall thread groove of the valve body has a spring seat and an adjusting hole at both ends makes the adjustment of the pressure regulating spring convenient; (4) The structure in which the oil plug is thread-fitted with the opening at the top of the valve body and is provided with a gasket makes the limiting part structure above the safety valve simpler, more compact, and has a wider installation range. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a sectional view of the present utility model.

[0018] In the figure: 1. Valve body, 2. Thread groove, 3. Oil plug, 4. Gasket, 5. First cavity, 6. Inner adjusting screw, 7. Adjusting hole, 8. Spring seat, 9. Pressure regulating spring, 10. Main spool, 11. Shoulder, 12. Inner channel of the main spool, 13. First stepped hole, 14. Second stepped hole, 15. Third stepped hole, 16. Valve ball, 17. Cylindrical spool, 18. Arc-shaped end face, 19. Valve cap, 20. Valve cap hole, 21. Second cavity, 22. Annular flow channel, 23. Third cavity, 24. Valve seat, 25. Upper cylinder, 26. Lower cylinder, 27. Sealing ring A, 28. Sealing ring B, 29. Sealing ring C, 30. First channel, 31. First channel port A, 32. First channel port B, 33. Second channel, 34. Second channel port A, 35. Second channel port B, 36. Third channel, 37. Third channel port A, 38. Third channel port B, 39. Hydraulic cylinder body, 40. Fourth channel, 41. Fourth channel port A, 42. Fourth channel port B, 43. Fifth channel, 44. Fifth channel port. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] The technical solution of the present utility model will be further specifically described below through specific embodiments and in conjunction with the drawings.

[0020] Embodiment:

[0021] As Figure 1An integrated built-in safety valve as shown includes a valve seat 24, which is composed of an upper cylinder 25 and a lower cylinder 26. The diameter of the upper cylinder 25 is smaller than that of the lower cylinder 26. A valve body 1 is sleeved outside the upper cylinder 25. With this design, the larger diameter of the lower cylinder 26 provides a larger supporting area for the valve body 1 sleeved outside the upper cylinder 25 above, which helps to increase the overall stability of the built-in safety valve and reduce the risk of deformation under high-pressure working conditions. The integrated structure with the valve body 1 sleeved outside the valve seat 24 has its internal parts completely encapsulated in the valve body 1, facilitating later installation, disassembly, and maintenance. A sealing ring A27 is provided at the mating surface between the upper cylinder 25 and the valve body 1. This structure can not only prevent the hydraulic oil inside the safety valve valve body 1 from leaking out and ensure its sealing performance but also prevent the valve seat 24 from slipping out of the valve body 1 by virtue of the elastic characteristics of the sealing ring itself.

[0022] A third channel 36 is also provided inside the valve seat 24. Above the third channel 36, there is a third channel port B38. The third channel port B38 is a cylindrical groove, and the diameter of the third channel port B38 is slightly larger than that of the third channel 36. A main spool 10 is arranged above the valve seat 24. The third channel 36 inside the valve seat 24 connects the hydraulic cylinder cavity and the valve body cavity above the valve seat 24. The third channel port B38 is designed as a cylindrical groove and is used in cooperation with the main spool 10 to play a main sealing role. The lower end of the main spool 10 is conical. The conical sealing structure formed by the cooperation of the conical surface at the lower end of the main spool 10 and the third channel port B38 of the valve seat 24 has a larger specific pressure and better sealing effect compared with the plane sealing structure. At the same time, the two parts do not need to be lapped, reducing the processing difficulty. The lower end of the main spool 10 and the opening edge of the third channel port B38 form a line contact. The sealing structure formed by this line contact has its main sealing line not set on the hydraulic cylinder, avoiding the problem that the hydraulic cylinder is prone to orifice ovality resulting in sealing failure and the secondary repair effect is not ideal, causing the scrapping of the hydraulic cylinder, saving costs; the sealing structure formed by this line contact has its main sealing line set on the valve seat 24. If the valve seat 24 has a problem of orifice ovality resulting in sealing failure, the difficulty and cost of its repair and processing are relatively low.

[0023] A main spool valve 10 is axially provided with a main spool valve inner channel 12 and several stepped holes, including a first stepped hole 13, a second stepped hole 14, and a third stepped hole 15. Among the above three stepped holes, the third stepped hole 15 has the largest diameter, the second stepped hole 14 is the second, and the first stepped hole 13 has the smallest diameter. The third stepped hole 15 has the largest height, the second stepped hole 14 is the second, and the first stepped hole 13 has the smallest height. A valve ball 16 is arranged in the second stepped hole 14. The lower end of the valve ball 16 is located in the first stepped hole 13. The diameter of the valve ball 16 is slightly smaller than the diameter of the second stepped hole 14 so that fluid can flow through the gap between the valve ball 16 and the second stepped hole 14. A cylindrical spool 17 is arranged in the third stepped hole 15. Both ends of the cylindrical spool 17 are provided with arc-shaped end faces 18. The arc-shaped end face 18 at the lower end of the cylindrical spool 17 is partially located in the second stepped hole 14. The diameter of the cylindrical spool 17 is slightly smaller than the diameter of the third stepped hole 15 so that fluid can flow through the gap between the cylindrical spool 17 and the third stepped hole 15. The valve ball 16 and the cylindrical spool 17 are both provided with a certain lifting amount along the axis. The combined structure of the valve ball 16 and the cylindrical spool 17 can play a dual-insurance role in the sealing performance. The cylindrical spool 17 has a larger weight, a faster return speed, and a higher return pressure compared to the valve ball 16, which is beneficial for quick sealing. The upper end of the main spool valve 10 is provided with an external thread. The lower side of the valve cap 19 is provided with a cylindrical groove. The side of the cylindrical groove is provided with an internal thread. The cylindrical groove opened on the lower side of the valve cap 19 and the upper end of the main spool valve 10 are connected and matched by threads. The valve cap 19 can limit the lifting height of the cylindrical spool 17 after being pressured at the lower end. A valve cap hole 20 is opened on the valve cap 19. The valve cap hole 20 is located above the third stepped hole 15. The diameter of the valve cap hole 20 is smaller than the diameter of the cylindrical spool 17. The purpose of opening the valve cap hole 20 is to facilitate the fluid in the third stepped hole 15 to enter the second cavity 21 through the valve cap 19. The main spool valve 10 is also provided with a shoulder 11. The purpose of this structure is to be used to abut and install the pressure regulating spring 9. An annular flow passage 22 is arranged between the side of the main spool valve 10 and the valve body 1. The annular flow passage 22 communicates the second cavity 21 and the third cavity 23.

[0024] The inner wall of the valve body 1 is provided with a threaded groove 2, on which an inner adjusting screw 6 is arranged. The threaded groove 2 has a certain length. The lower end of the threaded groove 2 is flush with the upper end surface of the valve cap 19, and the upper end of the threaded groove 2 extends all the way to the top of the valve body 1. The inner adjusting screw 6 can rotate along the threaded groove 2 to freely adjust its height position, which is convenient for adjustment. A pressure regulating spring 9 is arranged below the inner adjusting screw 6. The pressure regulating spring 9 is not limited to a cylindrical spring, and its shape can also adopt corresponding derivative forms such as a butterfly shape and a rectangular shape. One end of the inner adjusting screw 6 close to the pressure regulating spring 9 is provided with a spring seat 8, and the other end is provided with an adjusting hole 7. The adjusting hole 7 is of an internal hexagonal structure. The structure of arranging the spring seat 8 and the adjusting hole 7 at both ends of the inner adjusting screw 6 arranged on the threaded groove 2 on the inner wall of the valve body 1 makes it convenient to adjust the pressure regulating spring 9. Among them, the spring seat 8 at one end of the inner adjusting screw 6 is used to stably arrange the pressure regulating spring 9, and the adjusting hole 7 at the other end of the inner adjusting screw 6 can be adjusted by matching with an internal hexagonal wrench. An oil plug 3 is arranged in the top opening of the valve body 1. The oil plug 3 and the valve body 1 are in threaded fit through the threaded groove 2 and are provided with a gasket 4. The structure of the oil plug 2 and the top opening of the valve body 1 being in threaded fit and provided with a gasket 4 makes the limiting part structure above the safety valve simpler and more compact, and the height of the part of the limiting part outside the valve body 1 is smaller, so the installation occasion of the current safety valve is wider. In addition, this structure has a better sealing effect, can effectively prevent the leakage of hydraulic oil during overflow, and is more convenient for installation and disassembly. The space between the lower end surface of the oil plug 3 and the upper end surface of the inner adjusting screw 6 is the first cavity 5. The inner adjusting screw 6 rotates along the threaded groove 2 to adjust its height position, so the axial width of the first cavity 5 will also change with the change of the height position of the inner adjusting screw 6.

[0025] The valve seat 24 is provided with a first channel 30 and a second channel 33. The first channel 30 and the second channel 33 are symmetrically arranged with respect to the third channel 36. Both the first channel 30 and the second channel 33 in the valve seat 24 are part of the built-in oil return passage. The upper ends of the first channel 30 and the second channel 33 communicate with the inner cavity of the valve body above the valve seat 24. In the current embodiment, the lower end of the second channel 33 communicates with the part of the built-in oil return passage located within the hydraulic cylinder block 39. Generally, the lower end of either the first channel 30 or the second channel 33 communicates with the part of the built-in oil return passage located within the hydraulic cylinder block 39. The dual-channel design of the first channel 30 and the second channel 33 in the valve seat 24 can flexibly handle the situation where one of the channels fails, can adapt to more hydraulic cylinder blocks, and can also efficiently handle the situation where a large amount of hydraulic oil needs to be quickly released. The design that the first channel 30 and the second channel 33 in the valve seat are symmetrically arranged with respect to the third channel 36 can ensure a more uniform pressure distribution of the hydraulic oil when passing through the safety valve, which helps to improve the stability and reliability of the entire system. At the same time, the symmetrical structure helps to optimize the hydrodynamic performance, reduce the fluid resistance, and thus improve the fluid flow efficiency. The design of the built-in oil return passage allows the overflow hydraulic oil to flow back to the fuel tank after passing through the internal channel, avoiding external oil return pipelines. The structure is compact and beautiful. At the same time, it can avoid the problem that the plastic hose of the external oil return pipeline is particularly prone to aging and failure due to weather and external environment, resulting in hydraulic oil leakage. The lower end of the first channel 30 in the valve seat 24 is provided with a first channel port A31, and the upper end of the first channel 30 is provided with a first channel port B32. The diameters of both the first channel port A31 and the first channel port B32 are slightly larger than the diameter of the first channel 30. The lower end of the second channel 33 in the valve seat 24 is provided with a second channel port A34, and the upper end of the second channel 33 in the valve seat 24 is provided with a second channel port B35. The diameters of both the second channel port A34 and the second channel port B35 are slightly larger than the diameter of the second channel 33.

[0026] The described integrated built-in safety valve is installed on the hydraulic cylinder body 39. The hydraulic cylinder body 39 is provided with a cylindrical groove. A fourth channel 40 is opened in the hydraulic cylinder body 39. The fourth channel 40 communicates with the hydraulic cylinder cavity. The fourth channel port B42 at the upper end of the fourth channel 40 is aligned with the third channel port A37 at the lower end of the third channel 36 in the valve seat 24. The diameter of the fourth channel port B42 is slightly larger than the diameter of the third channel port A37. The diameter of the third channel port A37 is slightly larger than the diameter of the third channel 36 in the valve seat 24. A fifth channel 43 is opened in the hydraulic cylinder body 39. The fifth channel 43 is part of the built-in oil return passage. The upper end of the fifth channel 43 is aligned with the second channel port A34 at the lower end of the second channel 33 in the valve seat 24. The bottom surface of the cylindrical groove of the hydraulic cylinder body 39 abuts against the bottom surface of the valve seat 24, and the contact surface is sealed with a seal ring B28 and a seal ring C29. The seal ring B28 surrounds the third channel 36, and the seal ring C29 surrounds the first channel 30, the second channel 33, and the third channel 36. Internal threads are machined on the side surface of the cylindrical groove. External threads are machined at the lower end of the valve body 1 of the integrated built-in safety valve. The lower end of the valve body 1 is threadedly connected to the cylindrical groove. By rotating the valve body 1 until the lower end of the valve body 1 is in close contact with the valve seat 24 and at the same time the valve seat 24 is in close contact with the hydraulic cylinder body 39, the installation of the integrated built-in safety valve on the hydraulic cylinder body 39 is completed.

[0027] The described integrated built-in safety valve simultaneously has the functions of independent exhaust and unloading protection. The working principle of the present utility model is that under normal circumstances, the main spool 10 forms a tight line contact with the opening edge of the third channel port B38 of the valve seat 24 under the elastic force of the pressure regulating spring 9, sealing the hydraulic oil in the hydraulic cylinder block 39. When the hydraulic oil in the hydraulic chamber is subjected to abnormal external load interference and causes overpressure, and the oil pressure is greater than the setting pressure of the pressure regulating spring 9, the main spool 10 jumps up for overflow. The excess hydraulic oil sequentially passes through the fourth channel port A41, the fourth channel 40, the fourth channel port B42, the third channel port A37, the third channel 36, the third channel port B38 into the third cavity 23, and then sequentially passes through the second channel port B35, the second channel 33, the second channel port A34, the fifth channel 43, the fifth channel port 44 and finally returns to the fuel tank, thus realizing the function of unloading protection. In the case of non-overpressure, the valve port seals and the main spool 10 does not act. At the moment when the plunger is converted from the end moment of the suction stroke stage to the stroke stage, a high-pressure environment is quickly established in the hydraulic chamber. The bubbles attached to the hydraulic oil are squeezed into the inner channel 12 of the main spool below the valve ball 16 and the first stepped hole 13 in the main spool at this time, thus triggering the valve ball 16 to jump up. The bubbles together with a small amount of hydraulic oil then enter the second stepped hole 14 and enter the space between the valve ball 16 and the cylindrical spool 17 through the gap between the valve ball 16 and the second stepped hole 14. Under the action of pressure, the cylindrical spool 17 is pushed open and jumps up. The bubbles together with a small amount of hydraulic oil then enter the third stepped hole 15 and enter the second cavity 21 through the gap between the cylindrical spool 17 and the third stepped hole 15 and the valve cap hole 20 provided on the valve cap 19. The excess gas and a small amount of hydraulic oil in the second cavity 21 enter the third cavity 23 through the annular flow channel 22, and then sequentially pass through the second channel port B35, the second channel 33, the second channel port A34, the fifth channel 43, the fifth channel port 44 and are finally discharged. A small amount of oil will be carried out during the independent exhaust process. The compensation valve is used to control the replenishment of the hydraulic oil in the hydraulic cylinder, so the reduced oil volume can be replenished accordingly through the compensation valve. The valve ball 16, the cylindrical spool 17 and several stepped holes in the main spool also form a necessary sealing structure. When the plunger is in the suction stroke, the valve ball 16 and the cylindrical spool 17 fall back, thus avoiding the reverse suction of air and playing a double-insurance role for the sealing performance. During the operation of the metering pump, as the suction and stroke of the plunger alternate, the valve ball 16 and the cylindrical spool 17 in the integrated built-in safety valve can independently exhaust gas, ensuring that there is no free gas in the hydraulic chamber, thus ensuring the volumetric efficiency and flow rate. This function is particularly important for medium and small flow conditions, and there is no need to separately set an exhaust valve on the hydraulic cylinder, with a simple structure and convenient application.

[0028] The above-described embodiments are only the preferred solutions of the present utility model and do not impose any form of limitation on the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements on some of the technical features. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the utility model shall be included within the protection scope of the present utility model.

Claims

1. An integrated built-in safety valve, characterized in that: include: A valve seat (24), the valve seat (24) consisting of an upper cylinder (25) and a lower cylinder (26), the upper cylinder (25) being provided with a valve body (1) on its outer sleeve, a main valve core (10) being provided above the valve seat (24), and a first channel (30) and a second channel (33) being provided inside the valve seat (24).

2. An integrated built-in safety valve according to claim 1, characterized in that: The diameter of the upper cylinder (25) is smaller than the diameter of the lower cylinder (26).

3. An integrated built-in safety valve according to claim 1 or 2, characterized in that: A sealing ring A (27) is provided at the matching surface between the upper cylinder (25) and the valve body (1).

4. The integrated built-in safety valve according to claim 1, characterized in that: A third channel (36) is also provided in the valve seat (24), and a third channel opening B (38) is provided above the third channel (36), wherein the third channel opening B (38) is a cylindrical groove.

5. An integrated built-in safety valve according to claim 1, 2 or 4, characterized in that: The lower end of the main valve core (10) is conical.

6. The integrated built-in safety valve according to claim 4, characterized in that: The lower end of the main valve core (10) and the opening edge of the third channel port B (38) form a line contact.

7. An integrated built-in safety valve according to claim 4 or 6, characterized in that: The first channel (30) and the second channel (33) are symmetrically arranged with respect to the third channel (36).

8. The integrated built-in safety valve according to claim 1, characterized in that: The inner wall of the valve body (1) is provided with a thread groove (2), and the thread groove (2) is provided with an internal adjustment screw (6).

9. The integrated built-in safety valve according to claim 8, characterized in that: A pressure regulating spring (9) is provided below the inner regulating screw (6); a spring seat (8) is provided at one end of the inner regulating screw (6) close to the pressure regulating spring (9), and an regulating hole (7) is provided at the other end.

10. The integrated built-in safety valve according to claim 1, characterized in that: The one-piece built-in safety valve further comprises an oil plug (3), wherein the oil plug (3) is arranged in the top opening of the valve body (1), and the oil plug (3) and the valve body (1) are threadedly matched and provided with a sealing gasket (4).

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