A liquid control check valve and method of use

Abstract

The application relates to a liquid control one-way valve and a use method thereof. A valve rod is slidably arranged in an outlet chamber. A valve core is arranged at the end of the valve rod facing an inlet chamber. The valve core contacts a connecting part between the inlet chamber and the outlet chamber, and can block the connection between the inlet chamber and the outlet chamber. A control rod is also slidably arranged in a control chamber. The control rod extends into the inlet chamber. Under the action of the hydraulic pressure in the control chamber, the control rod can push the valve core at one end of the valve core to connect the inlet chamber and the outlet chamber. A slow flow structure is further arranged on the control rod. The slow flow structure can reduce the flow between the inlet chamber and the outlet chamber after the valve core is pushed. The slow flow structure of the application can prevent the rapid drop of a hydraulic support stand column, affect the stability, cause danger, and expand the structure to increase the blocking area of the flow resistance plate to increase the slow flow effect of the slow flow structure, and further ensure the stable drop of the column.

Description

Technical Field

[0001] This invention belongs to the field of coal mine machinery technology, and specifically relates to a hydraulically controlled check valve and its usage method. Background Technology

[0002] Hydraulic supports are one of the key pieces of equipment in fully mechanized coal mining faces. They are hydraulic power devices that use liquid pressure to generate supporting force and achieve automatic movement for roof support and management. They can reliably and effectively support and control the roof of the working face, isolate the goaf, and prevent gangue from entering the longwall face.

[0003] The hydraulically controlled check valve is one of the key components of a hydraulic support, often referred to as a "hydraulic lock." It is typically installed in the lower chamber of the hydraulic support column and the supporting jack. It controls the movement of the column and the supporting jack in two ways: first, it controls the normal extension and retraction of the hydraulic support column and the supporting jack, maintaining a proper working position; second, it locks the liquid in the working chamber, maintaining the supporting force until the pressure relief valve opens to release pressure, at which point the liquid in the lower chamber of the jack flows back, causing the column to descend.

[0004] However, with the existing hydraulic control check valve, the liquid in the lower chamber of the jack flows back too quickly, causing the column to descend too fast and making the hydraulic support operation unstable. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a hydraulically controlled check valve and its usage method.

[0006] The technical solution of this invention is implemented as follows:

[0007] A hydraulically controlled one-way valve includes a valve body, which is hollow and includes a control chamber, an inlet chamber, and an outlet chamber. One end of the inlet chamber is connected to the control chamber, and the other end is connected to the outlet chamber. The other ends of the control chamber and the outlet chamber are sealed by end caps. The valve body also has an inlet port, an outlet port, and a control port. The inlet port is connected to the inlet chamber, the outlet port is connected to the outlet chamber, and the control port is connected to the control chamber. The valve body is characterized by having a valve stem slidably disposed within the outlet chamber, with a valve core disposed at the end of the valve stem facing the inlet chamber. The valve core contacts the connection between the inlet and outlet chambers, blocking the connection between them. A control rod is also slidably disposed within the control chamber, extending into the inlet chamber. Under the hydraulic pressure of the control chamber, the control rod pushes the valve core at its end facing the valve core, connecting the inlet and outlet chambers. A flow-slowing structure is also provided on the control rod, which reduces the flow rate between the inlet and outlet chambers after the valve core is pushed.

[0008] The slow-flow structure operates when the hydraulic support column descends, preventing the liquid from flowing back from the outlet chamber to the inlet chamber at an excessively fast speed. This prevents the hydraulic support column from dropping rapidly, affecting stability, and causing danger.

[0009] Preferably, the slow-flow structure includes:

[0010] A flow barrier, which is used to block the flow of liquid, is arranged around the axis of the control rod;

[0011] Foldable power source;

[0012] A folding structure is provided inside the control rod;

[0013] The flow-blocking plate is connected to the folding structure. Under the action of the folding power source, the folding structure can push the flow-blocking plate, which is parallel to the axis of the control rod and is folded inside the control rod, out of the control rod and open the flow-blocking plate in a direction away from the axis of the control rod to block the flow of liquid.

[0014] Preferably, the folding structure includes:

[0015] A fixed post is coaxially disposed inside the control rod;

[0016] The fixed seat is fixedly sleeved on the fixed column near the valve core end;

[0017] The slide is slidably sleeved on the outside of the fixed column and located on the side of the fixed seat away from the valve core. The outer wall of the slide is sealed and slidably connected to the inner wall of the control rod. Under the action of the above-mentioned folding power source, the slide can slide closer to or away from the fixed seat.

[0018] Connecting rod;

[0019] The aforementioned baffle plate is rotatably connected to the slide at one end and extends toward the fixed seat at the other end. The connecting rod is rotatably connected to the fixed seat at one end and rotatably connected to the baffle plate at the other end.

[0020] Preferably, the folding power source is liquid entering the control chamber from the control port. The inner cavity of the control rod, the outer wall of the fixed column, and the upper end face of the slide form a slow-flow pushing cavity. The slow-flow pushing cavity is connected to the control chamber through a connecting hole on the control rod. The liquid in the control chamber can enter the slow-flow pushing cavity through the connecting hole and push the slide towards the fixed seat.

[0021] Preferably, the folding structure further includes a limiting block, which extends inward from the inner wall of the control rod.

[0022] The aforementioned slide block is I-shaped and includes:

[0023] Middle section;

[0024] A sliding section, which protrudes outward from the surface of the middle section and is slidably connected to the inner wall of the control rod; a hinged section, which protrudes outward from the surface of the middle section, and the aforementioned baffle plate is rotatably connected to the hinged section;

[0025] The sliding section and the hinge section are located on both sides of the limiting block. The limiting block can limit the movement of the slide towards the fixed seat by blocking the sliding section, and can limit the movement of the slide away from the fixed seat by blocking the hinge section.

[0026] Preferably, the folding structure is further provided with an enlarged structure, which increases the blocking area of ​​the flow-blocking plate to enhance the flow-slowing effect of the flow-slowing structure. The enlarged structure includes:

[0027] An enlarged seat is fixedly mounted on a baffle plate, and the interior of the enlarged seat is a sealed accommodating space; an enlarged baffle is slidably mounted inside the baffle plate.

[0028] An enlarging slider is provided within the enlarging seat, and is sealed and slidably connected to the inner wall of the enlarging seat. The enlarging slider divides the accommodating space of the enlarging seat into a first cavity and a second cavity. An enlarging push rod is fixedly connected at one end to the enlarging slider, and at the other end extends through the second cavity to the outside of the enlarging seat and is fixedly connected to the enlarging baffle.

[0029] Promote the expansion of sources;

[0030] Among them, the connection between the amplification source and the amplification seat can provide power for the sliding of the amplification slider, so that the amplification slide rod can slide out of the baffle plate with the amplification baffle.

[0031] Preferably, the amplification source includes:

[0032] An airbag is fixedly mounted on one end of the sliding section of the slide block facing the limiting block, and the airbag is filled with gas.

[0033] The trachea has one end connected to the air bag and the other end connected to the first cavity on the enlarged seat.

[0034] Preferably, each baffle plate has an enlarged baffle on both sides.

[0035] A method for using a hydraulically controlled check valve includes the following steps:

[0036] Step S1: Connect the inlet to the emulsion pump station via an oil pipe, connect the outlet to the lower oil chamber of the hydraulic support column via an oil pipe, and connect the control port to the guide pipe of the upper oil chamber of the hydraulic support column via an oil pipe.

[0037] Step S2: When the control valve of the hydraulic support is in the column raising position, the high-pressure liquid drawn from the emulsion pump station will enter the inlet chamber through the inlet pipe. The high-pressure liquid will squeeze the valve core, causing the valve core to move towards the outlet chamber. Then the inlet chamber and the outlet chamber are connected to each other. After the high-pressure liquid enters the outlet chamber, it flows out from the outlet to the lower oil chamber of the hydraulic support column, causing the column to rise.

[0038] Step S3: When the column is raised to the required height, the emulsion pump station stops supplying high-pressure liquid to the inlet chamber. At this time, the valve stem will drive the valve core to return to the connection between the inlet chamber and the outlet chamber under the action of the spring force and block the connection between the inlet chamber and the outlet chamber.

[0039] Step S4: When the column needs to be lowered, high-pressure liquid enters the upper oil chamber of the column through the oil guide pipe. At the same time, high-pressure liquid enters the control chamber through the oil pipe. The high-pressure liquid squeezes the upper end of the control rod, causing the control rod to push the valve core towards the valve core, thus connecting the inlet chamber and the outlet chamber. Then, the high-pressure liquid in the lower oil chamber will flow back to the outlet chamber through the outlet, then flow to the inlet chamber through the outlet, and finally flow back to the emulsion pump station through the inlet.

[0040] Step S5: Some of the high-pressure liquid in the control chamber will also enter the slow-flow push chamber, which is surrounded by the inner cavity of the control rod, the outer wall of the fixed column, and the upper end face of the slide, through the connecting hole set at the upper end of the control rod. The high-pressure liquid in the slow-flow push chamber will push the slide along the fixed column towards the fixed seat. The baffle plate will be gradually pushed outward from the control rod and opened away from the axis of the control rod to block the flow of liquid, so that the flow rate of liquid returning from the outlet chamber to the inlet chamber is reduced, which makes it easier for the column to descend stably.

[0041] Step S6: When the sliding section of the slide block slides to the limit block and is blocked by the limit block, the baffle plate stops opening and is now fully opened.

[0042] Step S7: When the column descends to the position, the high-pressure liquid stops supplying oil to the control chamber through the oil pipe. The control rod will then reset under the action of the spring force, causing the valve core to also reset to the connection between the inlet and outlet chambers and blocking the connection between the inlet and outlet chambers. The slide will also slide and reset along the fixed column under the action of the spring force, causing the baffle plate to retract.

[0043] Preferably, the method further includes step S8: when the sliding section of the slide block slides to the limiting block, it can be blocked by the limiting block. The airbag below the sliding section slides to the limiting block along with the slide block and will be squeezed by the limiting block and the sliding section. The gas in the airbag will go along the air tube to the first cavity, thereby pushing the expanding slider to drive the expanding push rod to move, so that the expanding push rod carries the expanding baffle out of the flow barrier, increasing the blocking area of ​​the flow barrier to increase the flow slowing effect of the flow slowing structure, and making it easier for the column to descend more stably.

[0044] The beneficial effects of this invention are as follows:

[0045] 1. The slow-flow structure works when the hydraulic support column descends, so that the backflow speed of the liquid from the outlet chamber to the inlet chamber is not too fast, which can prevent the hydraulic support column from falling suddenly, affecting stability and causing danger.

[0046] 2. Enlarging the structure increases the obstruction area of ​​the flow-blocking plate, thereby enhancing the flow-slowing effect of the flow-slowing structure and further ensuring the stable descent of the column. Attached Figure Description

[0047] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0048] Figure 1 This is a cross-sectional view of the hydraulically controlled check valve's slow-flow structure when it is not in operation.

[0049] Figure 2 A cross-sectional view of the slow-flow structure of the hydraulically controlled check valve during operation;

[0050] Figure 3 This is a magnified view of a portion of the image (A).

[0051] Figure 4 This is a magnified view of part B;

[0052] Figure 5 This is a top view of the slow-flow structure.

[0053] Reference numerals: 1. Valve body; 2. Control chamber; 3. Inlet chamber; 4. Outlet chamber; 5. End cap; 6. Inlet; 7. Outlet; 8. Control port; 9. Valve stem; 10. Valve core; 11. Control rod; 12. Slow-flow structure; 13. Baffle plate; 14. Slow-flow push chamber; 15. Connecting hole; 16. Fixing column; 17. Fixing seat; 18. Slide seat; 19. Connecting rod; 20. Limiting block; 21. Intermediate section; 22. Sliding section; 23. Hinge section; 24. Enlarging seat; 25. Enlarging baffle; 26. Enlarging slider; 27. Enlarging push rod; 28. First cavity; 29. ​​Second cavity; 30. Airbag; 31. Air tube. Detailed Implementation

[0054] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0055] like Figure 1As shown, a hydraulically controlled one-way valve includes a valve body 1. The valve body 1 is hollow and includes a control chamber 2, an inlet chamber 3, and an outlet chamber 4. One end of the inlet chamber 3 is connected to the control chamber 2, and the other end is connected to the outlet chamber 4. The other ends of the control chamber 2 and the outlet chamber 4 are both sealed by end caps 5. The valve body 1 also has an inlet port 6, an outlet port 7, and a control port 8. The inlet port 6 is connected to the inlet chamber 3, the outlet port 7 is connected to the outlet chamber 4, and the control port 8 is connected to the control chamber 2. A valve stem 9 is slidably disposed in the cavity 4. A valve core 10 is disposed at the end of the valve stem 9 facing the liquid inlet cavity 3. The valve core 10 is disposed at the connection between the liquid inlet cavity 3 and the liquid outlet cavity 4 and can block the communication between the liquid inlet cavity 3 and the liquid outlet cavity 4. A control rod 11 is also slidably disposed in the control cavity 2. The control rod 11 extends into the liquid inlet cavity 3. Under the action of hydraulic pressure in the control cavity 2, the end of the control rod 11 facing the valve core 10 can push the valve core 10 to connect the liquid inlet cavity 3 and the liquid outlet cavity 4.

[0056] Connect inlet 6 to the emulsion pump station via an oil pipe, connect outlet 7 to the lower oil chamber of the hydraulic support column via an oil pipe, and connect control port 8 to the guide pipe of the upper oil chamber of the hydraulic support column via an oil pipe. When the hydraulic support's control valve is in the rising position, the high-pressure liquid drawn from the emulsion pump station enters inlet chamber 3 through the inlet pipe. The high-pressure liquid squeezes valve core 10, causing it to move towards outlet chamber 4. Inlet chamber 3 and outlet chamber 4 then connect. After entering outlet chamber 4, the high-pressure liquid flows out from outlet 7 to the lower oil chamber of the hydraulic support column, causing the column to rise. Once the column has risen to the required height, the emulsion pump station stops pumping liquid. High-pressure liquid is supplied to the inlet chamber 3. At this time, under the action of the spring force, the valve stem 9 will drive the valve core 10 to return to the connection between the inlet chamber 3 and the outlet chamber 4 and block the connection between the inlet chamber 3 and the outlet chamber 4. When the column needs to be lowered, the high-pressure liquid enters the upper oil chamber of the column through the oil guide pipe. At the same time, the high-pressure liquid will enter the control chamber 2 through the oil pipe. The high-pressure liquid will squeeze the upper end face of the control rod 11, causing the end of the control rod 11 facing the valve core 10 to push the valve core 10 to connect the inlet chamber 3 and the outlet chamber 4. Then the high-pressure liquid in the lower oil chamber will flow back to the outlet chamber 4 through the outlet 7, then flow back to the inlet chamber 3 through the outlet chamber 4, and then flow back to the emulsion pump station through the inlet 6.

[0057] like Figure 2-4 As shown, the control lever 11 is also provided with a flow-slowing structure 12, which can reduce the flow rate between the inlet chamber 3 and the outlet chamber 4 after the valve core 10 is pushed.

[0058] The flow-slowing structure 12 includes a flow-blocking plate 13, a folding power source, and a folding structure. The flow-blocking plate 13 is used to block the flow of liquid and is arranged around the axis of the control rod 11. The folding structure is arranged inside the control rod 11. The flow-blocking plate 13 is connected to the folding structure. Under the action of the folding power source, the folding structure can push the flow-blocking plate 13, which is parallel to the axis of the control rod 11 and is folded inside the control rod 11, out of the control rod 11 and open the flow-blocking plate 13 in a direction away from the axis of the control rod 11 to block the flow of liquid.

[0059] like Figure 2 As shown, the folding power source is liquid entering the control chamber 2 from the control port 8. The inner cavity of the control rod 11, the outer wall of the fixed column 16, and the upper end face of the slide 18 form a slow-flow pushing cavity 14. The slow-flow pushing cavity 14 is connected to the control chamber 2 through the connecting hole 15 opened on the control rod 11. The liquid energy in the control chamber 2 enters the slow-flow pushing cavity 14 through the connecting hole 15 and pushes the slide 18 towards the fixed seat 17.

[0060] like Figure 3-4 As shown, the folding structure includes a fixed post 16, a fixed seat 17, a slide 18, and a connecting rod 19. The fixed post 16 is coaxially arranged inside the control rod 11; the fixed seat 17 is fixedly sleeved on the fixed post 16 near the valve core 10; the slide 18 is slidably sleeved outside the fixed post 16, tangentially located on the side of the fixed seat 17 away from the valve core 10, the outer wall of the slide 18 is sealed and slidably connected to the inner wall of the control rod 11, and the slide 18 can slide closer to or away from the fixed seat 17 under the action of the aforementioned folding power source; one end of the aforementioned baffle plate 13 is rotatably connected to the slide 18, and the other end extends toward the fixed seat 17; one end of the connecting rod 19 is rotatably connected to the fixed seat 17, and the other end of the connecting rod 19 is rotatably connected to the baffle plate 13.

[0061] When the column needs to be lowered, high-pressure liquid enters the upper oil chamber of the column through the oil guide pipe. At the same time, high-pressure liquid enters the control chamber 2 through the oil pipe. Some of the high-pressure liquid in the control chamber 2 enters the slow-flow push chamber 14, which is surrounded by the inner cavity of the control rod 11, the outer wall of the fixed column 16, and the upper end face of the slide 18, through the connecting hole 15 at the upper end of the control rod 11. The high-pressure liquid in the slow-flow push chamber 14 pushes the slide 18 to move along the fixed column 16 toward the fixed seat 17. The flow baffle 13 is gradually pushed outward from the control rod 11 and opened away from the axis of the control rod 11 to block the flow of liquid, so that the flow rate from the outlet chamber 4 back to the inlet chamber 3 is reduced, which facilitates the stable descent of the column.

[0062] The folding structure also includes a limiting block 20, which extends inward from the inner wall of the control rod 11. The slide 18 is I-shaped and includes a middle section 21, a sliding section 22, and a hinge section 23. The sliding section 22 protrudes outward from the surface of the middle section 21 and is slidably connected to the inner wall of the control rod 11; the hinge section 23 protrudes outward from the surface of the middle section 21, and the baffle plate 13 is rotatably connected to the hinge section 23. The sliding section 22 and the hinge section 23 are respectively located on both sides of the limiting block 20. The limiting block 20 can limit the movement of the slide 18 toward the fixed seat 17 by blocking the sliding section 22, and can also limit the movement of the slide 18 away from the fixed seat 17 by blocking the hinge section 23. When the sliding section 22 of the slide 18 slides to the limiting block 20 and is blocked by the limiting block 20, the baffle plate 13 stops opening, and at this time it has been opened to the correct position.

[0063] like Figure 4-5 As shown, the folding structure is further provided with an enlargement structure, which increases the blocking area of ​​the flow-blocking plate 13 to enhance the flow-slowing effect of the flow-slowing structure 12. The enlargement structure includes an enlargement seat 24, an enlargement baffle 25, an enlargement slider 26, an enlargement push rod 27, and a pushing and enlarging source. The enlargement seat 24 is fixedly mounted on the flow-blocking plate 13, and the interior of the enlargement seat 24 is a sealed accommodating space. The enlargement baffle 25 is slidably mounted within the flow-blocking plate 13, and an enlargement baffle 25 is provided on both sides of each flow-blocking plate 13. The enlargement slider 26 is mounted within the enlargement seat 24, and the enlargement slider 26 is sealed and slidably connected to the inner wall of the enlargement seat 24. The enlargement slider 26 divides the accommodating space of the enlargement seat 24 into a first cavity 28 and a second cavity 29. One end of the expanding push rod 27 is fixedly connected to the expanding slider 26, and the other end extends through the second cavity 29 to the outside of the expanding seat 24 and is fixedly connected to the expanding baffle 25; pushing the expanding source to connect with the expanding seat 24 can provide power for the sliding of the expanding slider 26, so that the expanding push rod carries the expanding baffle 25 out of the flow barrier 13.

[0064] The amplification source includes an airbag 30 and an air tube 31. The airbag 30 is fixedly installed at one end of the sliding section 22 of the slide block 18 facing the limiting block 20, and the airbag 30 is filled with gas; one end of the air tube 31 is connected to the airbag 30, and the other end is connected to the first cavity 28 on the amplification seat 24.

[0065] When the sliding section 22 of the slide block 18 slides to the limiting block 20, it can be blocked by the limiting block 20. The airbag 30 below the sliding section 22 follows the slide block to the limiting block 20 and will be squeezed by the limiting block 20 and the sliding section 22. The gas in the airbag 30 will go along the air tube 31 to the first cavity 28, thereby pushing the expanding slider 26 to drive the expanding push rod 27 to move, so that the expanding push rod 27, along with the expanding baffle 25, slides out of the flow deflector 13, increasing the blocking area of ​​the flow deflector 13 to increase the flow deflection effect of the flow deflector structure 12, making it easier for the column to descend more stably.

[0066] When the column descends to its position, the high-pressure liquid stops supplying oil to the control chamber 2 through the oil pipe. Then, the control rod 11 will reset under the action of the spring force, so that the valve core 10 will also reset to the connection between the inlet chamber 3 and the outlet chamber 4 and block the connection between the inlet chamber 3 and the outlet chamber 4. The slide 18 will also slide and reset along the fixed column 16 under the action of the spring force, so that the baffle plate 13 will retract.

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A kind of liquid control check valve, including valve body (1), the hollow including control cavity (2) in valve body (1), liquid inlet cavity (3) and liquid outlet cavity (4), liquid inlet cavity (3) one end with control cavity (2) communication, the other end with liquid outlet cavity (4) communication, control cavity (2) and the other end of liquid outlet cavity (4) are all blocked by end cover (5), valve body (1) still be provided with liquid inlet (6), liquid outlet (7) and control port (8), liquid inlet (6) with liquid inlet cavity (3) communication, liquid outlet (7) with liquid outlet cavity (4) communication, control port (8) with control cavity (2) communication, its characterized in that, The valve stem (9) is arranged in the liquid outlet cavity (4) and is provided with a valve core (10) at the end facing the liquid inlet cavity (3), the valve core (10) is arranged at the connection between the liquid inlet cavity (3) and the liquid outlet cavity (4) and can block the communication between the liquid inlet cavity (3) and the liquid outlet cavity (4), the control rod (11) is further arranged in the control cavity (2) and extends into the liquid inlet cavity (3), the control rod (11) can push the valve core (10) at one end facing the valve core (10) under the action of the hydraulic pressure of the control cavity (2) to make the liquid inlet cavity (3) and the liquid outlet cavity (4) communicate, and the flow regulating structure (12) is further arranged on the control rod (11), the flow regulating structure (12) can reduce the flow between the liquid inlet cavity (3) and the liquid outlet cavity (4) after pushing the valve core (10); The flow regulating structure (12) comprises: A flow blocking plate (13) is arranged around the axis of the control rod (11) to block the liquid flow; A folding power source; A folding structure is arranged in the control rod (11); The flow blocking plate (13) is connected with the folding structure, and under the action of the folding power source, the folding structure can push the flow blocking plate (13) which is parallel to the axis of the control rod (11) and folded in the control rod (11) out of the control rod (11) and make the flow blocking plate (13) open to block the liquid flow away from the axis of the control rod (11); The folding structure comprises: A fixed column (16) is coaxially arranged in the control rod (11); A fixed seat (17) is fixedly arranged on the fixed column (16) near the valve core (10); A sliding seat (18) is slidingly arranged outside the fixed column (16) and located away from the valve core (10) on the fixed seat (17), the outer wall of the sliding seat (18) is sealingly and slidingly connected with the inner wall of the control rod (11), and the sliding seat (18) can slide towards or away from the fixed seat (17) under the action of the above-mentioned folding power source; A connecting rod (19) is arranged; One end of the flow blocking plate (13) is rotatably connected to the sliding seat (18), the other end extends towards the fixed seat (17), one end of the connecting rod (19) is rotatably connected to the fixed seat (17), and the other end of the connecting rod (19) is rotatably connected to the flow blocking plate (13).

2. A pilot operated check valve according to claim 1, wherein The folding power source is the liquid entering the control cavity (2) from the control port (8), the inner cavity of the control rod (11), the outer wall of the fixed column (16) and the upper end surface of the sliding seat (18) form a flow regulating push cavity (14), the flow regulating push cavity (14) is in communication with the control cavity (2) through the connecting hole (15) arranged on the control rod (11), and the liquid in the control cavity (2) can enter the flow regulating push cavity (14) through the connecting hole (15) and push the sliding seat (18) to move towards the fixed seat (17).

3. A pilot operated check valve according to claim 2, wherein The folding structure further comprises a limiting block (20) which is formed by extending inward from the inner wall of the control rod (11), and the sliding seat (18) is in the shape of an I-beam and comprises: A middle section (21) The sliding section (22) protrudes outward from the surface of the middle section (21) and is in sliding connection with the inner wall of the control rod (11); The hinged section (23) protrudes outward from the surface of the middle section (21), and the above-mentioned flow barrier (13) is rotationally connected to the hinged section (23); The sliding section (22) and the hinged section (23) are arranged on the two sides of the limiting block (20), the limiting block (20) can limit the movement of the sliding seat (18) towards the fixed seat (17) by blocking the sliding section (22), and the limiting block (20) can limit the movement of the sliding seat (18) away from the fixed seat (17) by blocking the hinged section (23).

4. A pilot operated check valve according to claim 3, wherein The folding structure is further provided with an expansion structure, which can increase the blocking area of the flow barrier (13) to increase the flow slowing effect of the flow slowing structure (12), and the expansion structure comprises: The expansion seat (24) is fixedly arranged on the flow barrier (13), and the expansion seat (24) is a closed containing space; The expansion baffle (25) is slidingly arranged in the flow barrier (13); The expansion slider (26) is arranged in the expansion seat (24), the expansion slider (26) is sealingly and slidingly connected with the inner wall of the expansion seat (24), and the expansion slider (26) divides the containing space of the expansion seat (24) into a first cavity (28) and a second cavity (29); The expansion push rod (27) is fixedly connected with the expansion slider (26) at one end and extends to the outside of the expansion seat (24) through the second cavity (29) and is fixedly connected with the expansion baffle (25) at the other end; The expansion source is pushed; The expansion source is connected with the expansion seat (24) to provide power for the sliding of the expansion slider (26), so that the expansion slider (27) slides out of the flow barrier (13) with the expansion baffle (25).

5. A pilot operated check valve according to claim 4, wherein The expansion source comprises: The air bag (30) is fixedly arranged at one end of the sliding section (22) of the sliding seat (18) facing the limiting block (20), and the air bag (30) is filled with gas; The air pipe (31) is connected with the air bag (30) at one end and is in communication with the first cavity (28) of the expansion seat (24) at the other end.

6. A pilot operated check valve according to claim 5, wherein Each flow barrier (13) is provided with expansion baffles (25) on both sides.

7. A method of using a pilot operated check valve comprising the pilot operated check valve of claim 6, wherein, The method comprises the following steps: Step S1: connecting the liquid inlet (6) to the emulsion pump station through an oil pipe, connecting the liquid outlet (7) to the lower oil cavity of the hydraulic support column through an oil pipe, and connecting the control port (8) to the oil guide pipe of the upper oil cavity of the hydraulic support column through an oil pipe; Step S2: when the operating valve of the hydraulic support is in the column lifting position, the high-pressure liquid pumped out from the emulsion pump station enters the liquid inlet cavity (3) through the liquid inlet pipe, the high-pressure liquid squeezes the valve core (10), the valve core (10) moves towards the liquid outlet cavity (4), the liquid inlet cavity (3) and the liquid outlet cavity (4) are in communication, the high-pressure liquid enters the liquid outlet cavity (4) and then flows out from the liquid outlet (7) to the lower oil cavity of the hydraulic support column, so that the column rises upward; Step S3: When the column is raised to the required height, the emulsion pump station stops supplying high-pressure liquid into the liquid inlet cavity (3), at which time the valve stem (9) will drive the valve core (10) to reset to the connection between the liquid inlet cavity (3) and the liquid outlet cavity (4) under the action of the spring force and block the communication between the liquid inlet cavity (3) and the liquid outlet cavity (4); Step S4: When the column needs to be lowered, high-pressure liquid enters the oil cavity of the column through the oil guide pipe, At the same time, the high-pressure liquid will enter the control cavity (2) through the oil pipe, and the high-pressure liquid will extrude the upper end surface of the control rod (11) to push the valve core (10) towards the end of the valve core (10) to make the liquid inlet cavity (3) and the liquid outlet cavity (4) communicate, so that the high-pressure liquid in the lower oil cavity will flow back to the liquid outlet cavity (4) through the liquid outlet (7), then flow to the liquid inlet cavity (3) through the liquid outlet cavity (4), and then flow back to the emulsion pump station through the liquid inlet (6); Step S5: Part of the high-pressure liquid in the control cavity (2) will also enter the slow-flow push cavity (14) surrounded by the inner cavity of the control rod (11), the outer wall of the fixed column (16) and the upper end surface of the sliding seat (18) through the connecting hole (15) arranged on the upper end of the control rod (11), and the high-pressure liquid in the slow-flow push cavity (14) will push the sliding seat (18) to move along the fixed column (16) towards the fixed seat (17), the flow plate (13) will be gradually pushed out of the control rod (11) and opened away from the axis of the control rod (11) to block the liquid flow, so that the flow rate of the liquid outlet cavity (4) back to the liquid inlet cavity (3) is reduced, facilitating stable descent of the column; Step S6: When the sliding section (22) of the sliding seat (18) slides to the limit block (20), it can be blocked by the limit block (20), so that the flow plate (13) stops opening, and at this time it has been opened to the right position; Step S7: When the column is lowered to the right position, the high-pressure liquid stops supplying oil to the control cavity (2) through the oil pipe, so that the control rod (11) resets under the action of the spring force, the valve core (10) also resets to the connection between the liquid inlet cavity (3) and the liquid outlet cavity (4) and blocks the communication between the liquid inlet cavity (3) and the liquid outlet cavity (4), and the sliding seat (18) also resets under the action of the spring force along the fixed column (16), so that the flow plate (13) is retracted.

8. The method of using a pilot operated check valve of claim 7, wherein, Step S8: When the sliding section (22) of the sliding seat (18) slides to the limit block (20), it can be blocked by the limit block (20), and the air bag (30) below the sliding section (22) will be extruded by the limit block (20) and the sliding section (22) when it slides to the limit block (20), so that the gas in the air bag (30) will flow along the air pipe (31) to the first cavity (28), thereby pushing the enlarged sliding block (26) to drive the enlarged push rod (27) to move, so that the enlarged push rod (27) slides out of the flow plate (13) with the enlarged baffle (25), increases the blocking area of the flow plate (13) to increase the slow-flow effect of the slow-flow structure (12), and facilitates further stable descent of the column.

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