A shock-absorbing back-flushing filter for a fully-mechanized coal mining hydraulic support

Abstract

This invention discloses a backwash filter for reducing hydraulic shock in fully mechanized coal mining hydraulic supports. It includes a main valve body, a first electromagnetic pilot valve mounted on the main valve body, a first valve core assembly disposed in a first valve chamber of the main valve body, a second valve core assembly disposed in a second valve chamber of the main valve body, a first filter assembly disposed in a third valve chamber of the main valve body, and a second filter assembly disposed in a fourth valve chamber of the main valve body. The second and fourth valve chambers are connected. The first electromagnetic pilot valve is configured to adjust the opening of the first valve core assembly. This backwash filter for fully mechanized coal mining hydraulic supports, through the cooperation of the first electromagnetic pilot valve and the first valve core assembly, reduces the hydraulic shock during hydraulic cylinder startup. In fully mechanized coal mining hydraulic supports, it can reduce the hydraulic shock during hydraulic cylinder startup and stabilize the pressure and flow rate at the working port. Simultaneously, the valve core assembly and filter assembly are disposed within the same main valve body, improving integration.

Description

Technical Field

[0001] This invention belongs to the technical field of hydraulic supports for fully mechanized coal mining. Specifically, this invention relates to a backwash filter for hydraulic supports in fully mechanized coal mining. Background Technology

[0002] With increasing demands on the performance and reliability of fully mechanized coal mining equipment in underground coal mines, the hydraulic fluid in hydraulic systems such as hydraulic supports in underground coal mining faces needs to be pre-filtered through backwash filters to prevent dirt and impurities from entering the hydraulic systems and further improve the service life of various hydraulic equipment.

[0003] Chinese Patent Application No. 202420434989.6 discloses a backwash filter, including a valve body and a valve core assembly. The valve core assembly includes a valve core, a valve seat, an inlet valve sleeve, and a return valve sleeve. The valve core passes through the valve seat, and a hard seal connection is formed between the valve core and the valve seat. The valve core and the valve seat are made of metal.

[0004] In fully mechanized coal mining operations, hydraulic supports are core equipment, crucial for ensuring mining safety and efficiency. The backwash filter connects to a directional valve, which in turn connects to a hydraulic cylinder. The hydraulic cylinder is the key actuator for the hydraulic support to perform actions such as pushing and pulling the support. However, when the hydraulic cylinder starts, the sudden change in hydraulic oil flow rate can easily generate a strong impact, a problem particularly prominent in the pushing and pulling operations of high-end supports.

[0005] While conventional hydraulic valves (such as ordinary directional valves and pressure reducing valves) are used for pressure control in hydraulic systems, there is a lack of precise and efficient solutions for the impact characteristics of hydraulic cylinders during startup in coal mine fully mechanized hydraulic supports. Ordinary hydraulic valves cannot quickly and adaptively adjust to the sudden pressure changes during hydraulic cylinder startup, and therefore cannot effectively reduce the impact energy.

[0006] This invention provides a backwash filter that reduces the impact of hydraulic cylinder startup while improving integration. Summary of the Invention

[0007] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention provides a backwash filter for hydraulic supports in fully mechanized coal mining, with the purpose of reducing the impact of hydraulic cylinder startup while improving integration.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a backwash filter for reducing flushing in a fully mechanized hydraulic support for coal mines, comprising a main valve body, a first electromagnetic pilot valve disposed on the main valve body, a first valve core assembly disposed in a first valve chamber of the main valve body, a second valve core assembly disposed in a second valve chamber of the main valve body, a first filter assembly disposed in a third valve chamber of the main valve body, and a second filter assembly disposed in a fourth valve chamber of the main valve body, wherein the second valve chamber and the fourth valve chamber are connected, and the first electromagnetic pilot valve is configured to adjust the opening degree of the first valve core assembly.

[0009] The first valve core assembly includes a first threaded sleeve, a first valve sleeve connected to the first threaded sleeve, a first valve core movably disposed inside the first valve sleeve, and a first valve sleeve cooperating with the first valve core. The valve body is provided with an inlet and a working liquid port. The inlet and the first valve sleeve are arranged opposite to each other. The inlet and the inner cavity of the first valve sleeve are connected through a third liquid passage. The working liquid port is connected to a first liquid passage hole provided on the side wall of the first valve sleeve. The first liquid passage hole is connected to the inner cavity of the first valve sleeve. The first electromagnetic pilot valve is connected to the first valve cavity through a first pilot oil passage provided in the main valve body.

[0010] The end of the first valve core is provided with a fourth liquid passage for guiding liquid from the third liquid passage to the inner cavity of the first valve sleeve.

[0011] The fourth liquid passage includes a second liquid passage hole and a third liquid passage hole. The second liquid passage hole is connected to the third liquid passage, and the third liquid passage hole is connected to the inner cavity of the first valve sleeve.

[0012] The second liquid passage extends along the axial direction of the first valve core, and the third liquid passage extends radially from the inner surface of the second liquid passage to the outer surface of the first valve core.

[0013] Multiple third liquid passages are provided, and all third liquid passages are distributed around the second liquid passage, which is located at the center of the first valve core.

[0014] The second valve core assembly includes a second valve core, a second valve seat, an inlet valve sleeve, and a return valve sleeve. The second valve core passes through the second valve seat, and a hard seal connection is formed between the second valve core and the second valve seat. The second valve core and the second valve seat are made of metal.

[0015] The second valve core assembly also includes a second threaded sleeve and a piston. The inlet valve sleeve is located between the return valve sleeve and the second threaded sleeve. Both ends of the inlet valve sleeve are threadedly connected to the return valve sleeve and the second threaded sleeve, respectively. The piston is located inside the second threaded sleeve and is fixedly connected to one end of the second valve core. A return spring is provided between the piston and the inlet valve sleeve.

[0016] The piston is fixed to the second valve core by a nut, and a gasket and an elastic washer are provided between the nut and the piston.

[0017] The third valve chamber is connected to the third liquid passage through the first filter oil passage provided in the main valve body. The first electromagnetic pilot valve is connected to the third valve chamber through the third pilot oil passage provided in the main valve body. The liquid filtered by the first filter assembly enters the first electromagnetic pilot valve through the third pilot oil passage.

[0018] The first filter assembly includes a first connector and a second connector disposed opposite to each other, and a first filter screen disposed between the first connector and the second connector.

[0019] This invention relates to a backwash filter for reducing hydraulic shock in fully mechanized coal mining hydraulic supports. Through the cooperation of a first electromagnetic pilot valve and a first valve core assembly, it has the function of reducing the hydraulic cylinder starting impact. When used in fully mechanized coal mining hydraulic supports, it can reduce the hydraulic shock during hydraulic cylinder startup and stabilize the pressure and flow of the working oil port. At the same time, the valve core assembly and the filter assembly are set in the same main valve body, which improves the integration. Attached Figure Description

[0020] This manual includes the following figures, which illustrate the following:

[0021] Figure 1 This is a front view of the backwash filter of the present invention;

[0022] Figure 2 This is a left view of the backwash filter of the present invention;

[0023] Figure 3 This is a right view of the backwash filter of the present invention;

[0024] Figure 4 This is a schematic diagram showing the arrangement of the first valve core assembly and the second filter assembly within the main valve body.

[0025] Figure 5 This is a schematic diagram showing the arrangement of the second valve core assembly within the main valve body;

[0026] Figure 6 This is a schematic diagram showing the arrangement of the first filter component within the main valve body;

[0027] Figure 7 This is a cross-sectional view of the first valve core assembly;

[0028] Figure 8 This is a cross-sectional view of the first valve core;

[0029] Figure 9 This is a cross-sectional view of the second valve core assembly;

[0030] Figure 10 This is a cross-sectional view of the second valve core;

[0031] Figure 11 This is a functional symbol diagram of an automatic damping valve;

[0032] The components in the diagram are labeled as follows: 1. Main valve body; 2. First solenoid pilot valve; 3. First threaded sleeve; 4. First valve sleeve; 5. First valve core; 6. First valve seat; 7. Third liquid passage; 8. First liquid passage hole; 9. Second liquid passage hole; 10. Third liquid passage hole; 11. First connecting piece; 12. Second connecting piece; 13. First filter screen; 14. Second threaded sleeve; 15. Nut; 16. Elastic washer; 17. Gasket; 18. Piston; 19. Return spring; 20. 21. Inlet valve sleeve; 22. Second valve seat; 23. Second valve core; 24. Return valve sleeve; 25. Third valve seat; 26. Fourth through hole; 27. Fifth through hole; 28. Sixth through hole; 29. ​​First rod section; 30. Second rod section; 31. Third rod section; 32. Second solenoid pilot valve; 33. Third connector; 34. Fourth connector; 35. Second filter screen; 36. First through channel; 37. First filter oil passage; 38. First pilot oil passage. Detailed Implementation

[0033] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings, in order to help those skilled in the art to have a more complete, accurate and in-depth understanding of the concept and technical solutions of the present invention, and to facilitate its implementation.

[0034] It should be noted that in the following embodiments, the terms "first," "second," and "third" do not represent an absolute distinction in structure and / or function, nor do they represent the order of execution; they are merely for the convenience of description.

[0035] like Figures 1 to 11 As shown, the present invention provides a backwash filter for a fully mechanized hydraulic support in a coal mine, comprising a main valve body 1, a first electromagnetic pilot valve 2 disposed on the main valve body 1, a first valve core assembly disposed in a first valve chamber of the main valve body 1, a second valve core assembly disposed in a second valve chamber of the main valve body 1, a first filter assembly disposed in a third valve chamber of the main valve body 1, and a second filter assembly disposed in a fourth valve chamber of the main valve body 1. The first valve chamber and the third valve chamber are connected, and the second valve chamber and the fourth valve chamber are connected. The first electromagnetic pilot valve 2 is configured to adjust the opening of the first valve core assembly, and the second electromagnetic pilot valve 31 is configured to control the second valve core assembly to switch between a first working state and a second working state. The main valve body 1 is configured to connect to the hydraulic cylinder of the fully mechanized hydraulic support in a coal mine, and the first electromagnetic pilot valve 2 and the second electromagnetic pilot valve 31 are fixedly installed on the main valve body 1.

[0036] Specifically, such as Figures 1 to 3 and Figure 11 As shown, the main valve body 1 is equipped with a return port R, an inlet port PA, and a working port A. The inlet port PA and the working port A are located on two opposite surfaces of the main valve body 1. Liquid enters the main valve body 1 through the inlet port PA, and the liquid inside the main valve body 1 is discharged through the working port A. The working port A is connected to the directional valve of the fully mechanized coal mining hydraulic support via a hydraulic pipeline. The directional valve is connected to the hydraulic cylinder of the fully mechanized coal mining hydraulic support. The liquid exiting from the working port A enters the hydraulic cylinder after passing through the directional valve. The inlet port PA is connected to the second valve chamber through a first liquid passage 35. The second valve chamber is connected to the fourth valve chamber through a second liquid passage. The fourth valve chamber is connected to the first valve chamber through a third liquid passage 7. The third valve chamber is also connected to the first valve chamber through a third liquid passage 7. The second valve chamber is connected to the return port R through a return channel provided inside the main valve body 1. The return port R is used to discharge liquid outward.

[0037] like Figure 4 and Figure 7 As shown, the first valve core assembly includes a first threaded sleeve 3, a first valve sleeve 4 connected to the first threaded sleeve 3, a first valve core movably disposed inside the first valve sleeve 4, and a first valve seat 6 cooperating with the first valve core. The first threaded sleeve 3, the first valve sleeve 4, the first valve core, and the first valve seat 6 are coaxially arranged. The working fluid port A communicates with the first fluid passage 8 provided on the side wall of the first valve sleeve 4. The first fluid passage 8 communicates with the inner cavity of the first valve sleeve 4. The first electromagnetic pilot valve 2 communicates with the third valve cavity through the first pilot oil passage 37 provided in the main valve body 1. The third fluid passage 7 communicates with the first valve cavity. A one-way valve is also provided in the first pilot oil passage 37. The one-way valve ensures that the liquid can only flow from the third valve cavity to the first pilot oil passage 37 and enter the first electromagnetic pilot valve 2, and the liquid cannot flow in the opposite direction.

[0038] like Figure 4 and Figure 7As shown, the first valve sleeve 4 is a cylinder with open ends and a hollow interior. A first threaded sleeve 3 is connected to one end of the first valve sleeve 4 and is threaded to the main valve body 1. The first threaded sleeve 3 has external threads. The first valve sleeve 4 is sandwiched between the first threaded sleeve 3 and a stepped surface within the first valve cavity. The first valve core is located within the inner cavity of the first valve sleeve 4, which has a stepped surface for axially limiting the first valve core. The first valve seat 6 is installed in the other end opening of the first valve sleeve 4. The first valve seat 6 cooperates with the first valve core to achieve a seal. The head of the first valve core has a sealing cone surface for contacting the first valve seat 6. The first valve seat 6 has a ring-shaped structure with a central hole at its center to accommodate the first valve core. The diameter of the central hole is smaller than the outer diameter of the first valve core. Both the first valve core and the first valve seat 6 are made of metal, specifically 3Cr13. The first valve core and the first valve seat 6 have a hard seal connection, enhancing the sealing performance. Compared to soft material seals, hard seals not only have better sealing performance but can also withstand ultra-high pressure, resulting in a longer service life for the pressure relief valve.

[0039] like Figure 3 and Figure 7 As shown, the first fluid passage 8 is a through hole formed in the annular sidewall of the first valve sleeve 4. Multiple first fluid passages 8 are provided, located between the first valve seat 6 and the first threaded sleeve 3. Oil entering the first valve sleeve 4 through the third fluid passage 7 can push the first valve core towards the first threaded sleeve 3, causing the first valve core to separate from the first valve seat 6. After the first valve core is completely separated from the first valve seat 6, the automatic damping valve is at its maximum opening, and the fluid flow rate of the automatic damping valve is at its maximum. The fluid exiting the automatic damping valve enters the hydraulic cylinder through the reversing valve.

[0040] like Figure 4 and Figure 7As shown, the end of the first valve core is provided with a fourth liquid passage for guiding liquid from the third liquid passage 7 to the inner cavity of the first valve sleeve 4. The fourth liquid passage includes a second liquid passage hole 9 and a third liquid passage hole 10. The diameters of the second liquid passage hole 9 and the third liquid passage hole 10 are smaller than the diameter of the central hole of the first valve seat 6. The second liquid passage hole 9 communicates with the third liquid passage 7, and the third liquid passage hole 10 communicates with the inner cavity of the first valve sleeve 4. The second liquid passage hole 9 extends axially along the first valve core, and the third liquid passage hole 10 extends radially from the inner surface of the second liquid passage hole 9 to the outer surface of the first valve core. Multiple third liquid passage holes 10 are provided, all of which are distributed around the second liquid passage hole 9, which is located at the center of the first valve core. The second liquid passage 9 extends from the end face of the first valve core facing the third liquid passage 7 along the axial direction of the first valve core into the interior of the first valve core. The second liquid passage 9 is located at the center of the first valve core. The second liquid passage 9 and the first valve seat 6 are coaxially arranged. All the third liquid passages 10 are evenly distributed circumferentially with the axis of the second liquid passage 9 as the center line.

[0041] When the second valve core assembly is in the first working state, the first electromagnetic pilot valve 2 delivers liquid to the first valve chamber of the main valve body 1 through the first pilot oil passage 37. The liquid in the first valve chamber enters the inner cavity of the first valve sleeve 4 through the control hole provided on the annular side wall of the first threaded sleeve 3. The control hole provided on the annular side wall of the first threaded sleeve 3 is connected to the inner cavity of the first threaded sleeve 3. The inner cavity of the first threaded sleeve 3 is connected to the inner cavity of the first valve sleeve 4, so that the liquid enters the tail of the first valve core (the head and tail of the first valve core are the two ends of the first valve core in the axial direction), applies hydraulic pressure to the first valve core, and pushes the first valve core to move axially toward the first valve seat 6, so that the sealing cone surface of the head of the first valve core contacts the first valve seat 6. At this time, the automatic de-flushing valve is in the minimum opening state, and the liquid in the third liquid passage 7 can only enter the inner cavity of the first valve sleeve 4 through the fourth liquid passage.

[0042] Therefore, after the first valve core contacts the first valve seat 6, the second liquid passage 9 is used to guide the liquid from the third liquid passage 7 to the third liquid passage 10. The liquid in the second liquid passage 9 enters the third liquid passage 10, and the liquid in the third liquid passage 10 finally enters the inner cavity of the first valve sleeve 4. At this time, the liquid can only enter the inner cavity of the first valve sleeve 4 through the fourth liquid passage, and then enter the working liquid port through the first liquid passage 8. The automatic de-flushing valve is in the minimum opening state.

[0043] The aforementioned backwash filter with reduced backwashing capacity, through the cooperation of the first electromagnetic pilot valve 2 and the first valve core assembly, has the function of reducing the hydraulic cylinder starting impact. When used in the hydraulic support of fully mechanized coal mining, it can reduce the hydraulic shock when the hydraulic cylinder starts and stabilize the pressure and flow of the working oil port.

[0044] During operation, the system detects signals such as the action of the directional valve and the start and stop of the hydraulic cylinder. When the triggering conditions are met, the first electromagnetic pilot valve 2 is energized. The first electromagnetic pilot valve 2 delivers liquid to the first valve chamber of the main valve body 1 through the first pilot oil passage 37, controls the first valve core to move, reduces the opening of the backwash filter, weakens the impact energy generated by the hydraulic cylinder impact pressure through throttling, avoids the impact from being transmitted to downstream components, reduces the impact energy input from the "source", and ensures stable working oil port pressure.

[0045] like Figure 6 As shown, a first filter assembly is installed in the third valve chamber of the main valve body 1. The first filter assembly filters the oil. The third valve chamber is connected to the third liquid passage 7 through the first filter oil passage 36 installed in the main valve body 1. The first electromagnetic pilot valve 2 is connected to the third valve chamber through the first pilot oil passage 37 installed in the main valve body 1. The liquid filtered by the first filter assembly enters the first electromagnetic pilot valve 2 through the first pilot oil passage 37.

[0046] like Figure 6 As shown, the first filter assembly includes a first connector 11 and a second connector 12 disposed opposite to each other, and a first filter screen 13 disposed between the first connector 11 and the second connector 12. The first filter screen 13 is used to filter liquid. The first connector 11 is threadedly connected to the main valve body 1, and the first connector 11 is provided with an external thread. The first connector 11, the first filter screen 13, and the second connector 12 are coaxially arranged. A protrusion is provided at the center of the first connector 11. The protrusion is a hollow cylindrical structure. Filter holes for liquid to pass through are provided on the annular sidewall of the protrusion. The first filter screen 13 is sleeved on the protrusion. The central hole of the protrusion is connected to the first pilot oil passage 37. Multiple filter holes are provided, densely distributed on the annular sidewall of the protrusion, and distributed around the central hole of the protrusion. The filter holes are connected to the central hole of the protrusion. Liquid filtered by the first filter screen 13 enters the central hole of the protrusion and finally flows into the first electromagnetic pilot valve 2 through the first pilot oil passage 37. The second connector 12 has a mounting hole at its center for inserting the protrusion on the first connector 11. The mounting hole is a threaded hole, and the protrusion is threadedly connected to the second connector 12. The two ends of the first filter screen 13 are bonded to the first connector 11 and the second connector 12 respectively, forming a complete filter core.

[0047] like Figure 5 and Figure 9As shown, the second electromagnetic pilot valve 31 communicates with the second valve chamber through the second pilot oil passage provided in the main valve body 1. The second valve core assembly includes a second threaded sleeve 14, a piston 18, a second valve core 22, a second valve seat 21, an inlet valve sleeve 20, and a return valve sleeve 23. The second valve core 22 passes through the second valve seat 21, and a hard seal connection is formed between the second valve core 22 and the second valve seat 21. The second valve core 22 and the second valve seat 21 are made of metal. The second threaded sleeve 14 is threadedly connected to the main valve body 1. The second threaded sleeve 14 has a structure that is open at one end, closed at the other end, and hollow inside. The inlet valve sleeve 20 and the return valve sleeve 23 have structures that are open at both ends and hollow inside. The second valve core 22, the second valve seat 21, the second threaded sleeve 14, the inlet valve sleeve 20, and the return valve sleeve 23 are coaxially arranged. The inlet valve sleeve 20 is located between the return valve sleeve 23 and the second threaded sleeve 14. The two ends of the inlet valve sleeve 20 are threadedly connected to the return valve sleeve 23 and the second threaded sleeve 14, respectively. The two ends of the inlet valve sleeve 20 are provided with internal threads.

[0048] In this embodiment, the second valve core 22 and the second valve seat 21 are made of metal, preferably 3Cr13. Compared with soft material seals, hard seals not only have better sealing performance but can also withstand ultra-high pressure, extending the service life of the second valve core assembly. The second valve core 22 is provided with a first outer sealing surface that contacts the second valve seat 21, and the second valve seat 21 is provided with a first inner sealing surface that contacts the first outer sealing surface. Both the first outer sealing surface and the first inner sealing surface are conical surfaces and are coaxially arranged.

[0049] like Figure 9 As shown, piston 18 is located inside the second threaded sleeve 14. One end of piston 18 is fixedly connected to the second valve core 22. A return spring 19 is provided between piston 18 and inlet valve sleeve 20. The second threaded sleeve 14 is sleeved on piston 18, and the return spring 19 is sleeved on the second valve core 22. Piston 18 and second valve core 22 are coaxially arranged. Piston 18 is fixed on second valve core 22 by nut 15. A washer 17 and an elastic washer 16 are provided between nut 15 and piston 18. Second valve core 22 and piston 18 move synchronously.

[0050] like Figure 9 and Figure 10As shown, the second valve core 22 includes a first rod segment 28, a second rod segment 29, and a third rod segment 30 connected in sequence. All three segments are cylindrical and coaxially arranged, with their diameters gradually increasing. The first rod segment 28 is threadedly connected to the nut 15. A piston 28 is fitted onto the first rod segment 28, sandwiched between the nut 15 and the end face of the second rod segment 29. The outer diameter of the second rod segment 29 is smaller than the diameter of the central hole of the second valve seat 21. An inlet valve sleeve 30 and a return spring 29 are fitted onto the second rod segment 29. The return spring 29 is a cylindrical helical spring and a compression spring. The third rod segment 30 mates with the second valve seat 21. The first end of the third rod segment 30 has a first external sealing surface, and the second end has a second external sealing surface. The first and second ends of the third rod segment 30 are opposite ends of the second rod segment 29 in the axial direction.

[0051] like Figure 9 As shown, the inlet valve sleeve 30 is provided with a fourth liquid passage hole 25. Multiple fourth liquid passage holes 25 are provided, each a radially penetrating through-hole on the annular sidewall of the inlet valve sleeve 30. The axis of the fourth liquid passage hole 25 forms an acute angle with the axis of the inlet valve sleeve 30. The return valve sleeve 23 is provided with a fifth liquid passage hole 26. Multiple fifth liquid passage holes 26 are provided, each a radially penetrating through-hole on the annular sidewall of the return valve sleeve 23. The axis of the fifth liquid passage hole 26 forms an acute angle with the axis of the return valve sleeve 23. The return valve sleeve 23 is provided with a sixth liquid passage hole 27, located between the fourth and sixth liquid passage holes 25. Both the fifth and sixth liquid passage holes 26 are connected to the connecting hole 17. Multiple sixth liquid passages 27 are provided. Each sixth liquid passage 27 is a through hole radially extending through the annular sidewall of the return valve sleeve 23. The sixth liquid passage 27 is a circular hole, and its axis forms an acute angle with the axis of the return valve sleeve 23. The fourth liquid passage 25, the fifth liquid passage 26, and the sixth liquid passage 27 are designed with oblique holes, which makes the liquid flow more smoothly, reduces resistance loss, and is easier to process.

[0052] like Figure 9 and Figure 10As shown, a third valve seat 24 is provided inside the return valve sleeve 23. The third valve seat 24 is made of polyoxymethylene. After the second outer sealing surface contacts the third valve seat 24, a seal is achieved, and the second valve core assembly is in the second working state. Liquid from the inlet cannot pass through the second valve core assembly, and the fourth liquid passage hole 25 and the fifth liquid passage hole 26 are in a connected state. The second outer sealing surface is a conical surface, coaxial with the first outer sealing surface, and the outer edge of the second outer sealing surface is connected to the outer circular surface of the third rod segment 30. After the second valve seat 21 contacts the first outer sealing surface of the second valve core 22, the second valve core assembly is opened, the fourth liquid passage hole 25 and the fifth liquid passage hole 26 are in a disconnected state, and the sixth liquid passage hole 27 is in a connected state with the second liquid passage channel. Liquid from the second valve cavity can enter the second filter assembly for filtration, and the second valve core assembly is in the first working state.

[0053] like Figure 4 As shown, a second filter assembly is installed in the fourth valve chamber of the main valve body 1. The second filter assembly filters the oil. The fourth valve chamber is connected to the third liquid passage 7 through the second filter oil passage installed in the main valve body 1. The first electromagnetic pilot valve 2 is connected to the fourth valve chamber through the first pilot oil passage 37 installed in the main valve body 1. The liquid filtered by the second filter assembly enters the third liquid passage 7 through the second filter oil passage.

[0054] like Figure 4 As shown, the second filter assembly includes a third connector 32 and a fourth connector 33 disposed opposite to each other, and a second filter screen 34 disposed between the third connector 32 and the fourth connector 33. The second filter screen 34 is used to filter the liquid. The third connector 32 is threaded to the main valve body 1 and has an external thread. The third connector 32, the second filter screen 34, and the fourth connector 33 are coaxially arranged. The liquid entering the fourth valve chamber is filtered by the second filter screen 34, passes through the central hole of the fourth connector 33, and finally flows into the third liquid passage 7 through the second filter oil passage. The two ends of the second filter screen 34 are bonded to the third connector 32 and the fourth connector 33 respectively, forming a complete filter.

[0055] The aforementioned anti-flush backwash filter features a modular integrated design with multiple valve chambers and components. Each component is connected through internal oil passages, eliminating the need for additional external pipelines, shortening the oil path, reducing energy loss, and integrating anti-flush filtration functions. It boasts a high degree of integration while making the entire filter smaller, suitable for the compact installation environment of coal mine fully mechanized mining equipment, and supports automated control.

[0056] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the inventive concept and technical solution; or the direct application of the inventive concept and technical solution to other situations without modification, are all within the protection scope of the present invention.

Claims

1. A backwash filter for reducing flushing in fully mechanized hydraulic supports in coal mines, characterized in that: The system includes a main valve body, a first electromagnetic pilot valve and a second electromagnetic pilot valve disposed on the main valve body, a first valve core assembly disposed in a first valve chamber of the main valve body, a second valve core assembly disposed in a second valve chamber of the main valve body, a first filter assembly disposed in a third valve chamber of the main valve body, and a second filter assembly disposed in a fourth valve chamber of the main valve body. The second valve chamber and the fourth valve chamber are connected. The first electromagnetic pilot valve is configured to adjust the opening of the first valve core assembly to reduce the hydraulic shock when the hydraulic cylinder is started. The second electromagnetic pilot valve is connected to the second valve chamber through a second pilot oil passage disposed in the main valve body. The second electromagnetic pilot valve is configured to control the second valve core assembly to switch between a first working state and a second working state. The first electromagnetic pilot valve and the second electromagnetic pilot valve are fixedly mounted on the main valve body. The first valve core assembly includes a first threaded sleeve, a first valve sleeve connected to the first threaded sleeve, a first valve core movably disposed inside the first valve sleeve, and a first valve sleeve cooperating with the first valve core. The valve body is provided with an inlet and a working inlet. The inlet and the first valve sleeve are arranged opposite to each other. The inlet and the inner cavity of the first valve sleeve are connected through a third liquid passage. The working inlet is connected to a first liquid passage hole provided on the side wall of the first valve sleeve. The first liquid passage hole is connected to the inner cavity of the first valve sleeve. The first electromagnetic pilot valve is connected to the first valve cavity through a first pilot oil passage provided in the main valve body. The end of the first valve core is provided with a fourth liquid passage for guiding liquid from the third liquid passage to the inner cavity of the first valve sleeve. The fourth liquid passage includes a second liquid passage hole and a third liquid passage hole. The second liquid passage hole communicates with the third liquid passage and the third liquid passage hole communicates with the inner cavity of the first valve sleeve. When the second valve core assembly is in the first working state, the first electromagnetic pilot valve delivers liquid to the first valve chamber of the main valve body through the first pilot oil passage. The liquid in the first valve chamber enters the inner cavity of the first valve sleeve through the control hole provided on the annular side wall of the first threaded sleeve. The inner cavity of the first threaded sleeve is connected to the inner cavity of the first valve sleeve. The liquid enters the tail of the first valve core, applies hydraulic pressure to the first valve core, and pushes the first valve core to move axially toward the first valve seat, so that the sealing cone surface of the head of the first valve core contacts the first valve seat. The liquid in the third liquid passage can only enter the inner cavity of the first valve sleeve through the fourth liquid passage, and then enters the working liquid port through the first liquid passage. The first electromagnetic pilot valve is connected to the third valve chamber through the first pilot oil passage provided in the main valve body. The liquid filtered by the first filter assembly enters the first electromagnetic pilot valve through the first pilot oil passage.

2. The backwash filter according to claim 1, characterized in that: The second liquid passage extends along the axial direction of the first valve core, and the third liquid passage extends radially from the inner surface of the second liquid passage to the outer surface of the first valve core.

3. The backwash filter according to claim 2, characterized in that: Multiple third liquid passages are provided, and all third liquid passages are distributed around the second liquid passage, which is located at the center of the first valve core.

4. The backwash filter according to claim 1, characterized in that: A one-way valve is provided in the first pilot oil passage. The one-way valve ensures that the liquid can only flow from the third valve chamber to the first pilot oil passage and enter the first electromagnetic pilot valve. The liquid cannot flow in the opposite direction.

5. The backwash filter according to any one of claims 1 to 4, characterized in that: The second valve core assembly includes a second valve core, a second valve seat, an inlet valve sleeve, and a return valve sleeve. The second valve core passes through the second valve seat, and a hard seal connection is formed between the second valve core and the second valve seat. The second valve core and the second valve seat are made of metal.

6. The backwash filter according to claim 5, characterized in that: The second valve core assembly also includes a second threaded sleeve and a piston. The inlet valve sleeve is located between the return valve sleeve and the second threaded sleeve. Both ends of the inlet valve sleeve are threadedly connected to the return valve sleeve and the second threaded sleeve, respectively. The piston is located inside the second threaded sleeve and is fixedly connected to one end of the second valve core. A return spring is provided between the piston and the inlet valve sleeve.

7. The backwash filter according to claim 6, characterized in that: The piston is fixed to the second valve core by a nut, and a gasket and an elastic washer are provided between the nut and the piston.

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