A positive feedback quick response safety valve for hydraulic support

Abstract

The present invention belongs to the technical field of safety valves for hydraulic supports, and specifically relates to a positive feedback, rapid-response safety valve for hydraulic supports. The valve comprises a valve body, a main valve component, and a pilot valve component. The main valve component comprises a main valve core, a filter, and a main return spring, while the pilot valve component comprises a pilot valve sleeve, a pilot return spring, a locking sleeve, a lower ball valve, a push rod, a pilot valve seat, an upper ball valve, a guide spring seat, a pressure-regulating spring, and an adjusting screw. During the opening process of the main valve core, its upper control chamber is isolated from the P port, thereby accelerating the outward discharge of liquid from the control chamber and the upward movement and opening speed of the main valve core. During closing, the valve core relies not only on the spring force of the main return spring but also on the pressure at the P port, with high-pressure liquid accelerating the downward closing speed of the main valve core. The present invention enables the safety valve to exhibit a positive feedback promoting effect during both the opening and closing processes, thereby improving the safety valve's response speed and reducing or even eliminating the accident rate of hydraulic supports experiencing column expansion, cylinder explosion, and top penetration due to impact loads.

Description

Technical Field

[0001] The present invention belongs to the technical field of safety valves for hydraulic supports, and in particular relates to a positive feedback type quick response safety valve for hydraulic supports. Background Art

[0002] Hydraulic supports in coal mines support and manage the roof, often bearing its impact loads. Due to the large cross-sectional area of the hydraulic support column cavity, when the roof rapidly sinks, the existing safety valve cannot quickly and promptly drain the liquid from the column cavity, causing a sharp increase in pressure. Sometimes, excessive pressure in the column cavity can even lead to column expansion, explosion, and roof penetration, seriously threatening production safety. Existing safety valves suffer from slow opening and closing responses due to their structure and principle. Summary of the Invention

[0003] The purpose of the present invention is to reduce or even eliminate accidents such as cylinder expansion, cylinder explosion, and roof penetration caused by impact loads on hydraulic supports, thereby ensuring safe production on fully mechanized mining working faces in coal mines.

[0004] In order to achieve the above-mentioned object, the present invention provides the following technical solutions: a hydraulic support positive feedback type fast response safety valve, comprising a valve body, a main valve component, and a pilot valve component;

[0005] The main valve components include a main valve core and a main return spring. The main valve core is slidingly sealed and assembled in the valve body. The main return spring uses the valve body as support to push the main valve core to block the passage between the liquid inlet and the liquid outlet on the valve body.

[0006] The main valve core is hollow inside, and the pilot valve component is assembled on the valve body and slides and seals with the inner cavity of the main valve core. The main valve core control cavity is formed between the main valve core, the valve body and the pilot valve component;

[0007] A main flow channel and a secondary flow channel are provided in the pilot valve component, and the liquid inlet is connected to the valve body through the inner cavity of the main valve core and the main flow channel. The main flow channel includes a straight channel section, the upper port of the straight channel section is equipped with an upper ball valve, and the lower port is equipped with a lower ball valve. A push rod is installed in the straight channel section, and the upper ball valve, the lower ball valve and the push rod are arranged along the same axis. The upper ball valve and the lower ball valve are pushed toward the straight channel section by springs respectively, and the length of the push rod is greater than the length of the straight channel section. When the pressure at the liquid inlet is lower than the set pressure, the upper ball valve blocks the upper port, and the push rod pushes the lower ball valve to open the lower port; the secondary flow channel is located between the upper ball valve and the lower ball valve, and the secondary flow channel is cross-connected with the straight channel section. The liquid inlet is connected to the main valve core control cavity after passing through the inner cavity of the main valve core, the main flow channel and the secondary flow channel.

[0008] Furthermore, the pilot valve component includes a pilot valve sleeve, the lower end of the pilot valve sleeve is slidingly sealed with the inner cavity of the main valve core, and the upper end is fastened to the valve body by a fastening screw, the main reset spring sleeve is at the lower end of the pilot valve sleeve, and the two ends of the main reset spring are respectively abutted against the upper end face of the pilot valve sleeve and the step surface of the inner cavity of the main valve core; the main flow channel and the secondary flow channel are integrated in the pilot valve sleeve.

[0009] Furthermore, a single-stage stepped hole is provided at the upper end of the pilot valve sleeve, and a two-stage stepped hole is provided at the lower end; the single-stage stepped hole and the two-stage stepped hole are connected;

[0010] The first step hole of the single-stage stepped hole is equipped with an upper ball valve, a guide spring seat, a pressure regulating spring, and an adjusting screw. The adjusting screw is threadedly connected to the first step hole. The lower end surface of the guide spring seat is provided with a groove, and the upper ball valve is placed in the groove. The outer periphery of the guide spring seat is provided with a step, and the pressure regulating spring is placed between the adjusting screw and the step of the guide spring seat. The cavity within the adjusting screw in the first step hole is connected to the outside.

[0011] The locking sleeve and the pilot valve seat are installed in sequence from bottom to top in the two-stage stepped hole. The mechanical limit surface of the locking sleeve is in close contact with the first step surface of the two-stage stepped hole. The upper end surface of the locking sleeve is in close contact with the lower end surface of the pilot valve seat. A through hole is provided inside the locking sleeve. The lower ball valve and the pilot return spring are installed in sequence from top to bottom in the through hole.

[0012] The upper end surface of the pilot valve seat is flush with the step surface of the single-stage stepped hole, and the mechanical limit surface of the pilot valve seat is in contact with the second-stage step surface of the two-stage stepped hole; a center hole is opened vertically inside the pilot valve seat, and the push rod is placed in the center hole. The two ends of the center hole are the upper and lower valve ports, the upper ball valve cooperates with the upper valve port of the pilot valve seat, and the lower ball valve cooperates with the lower valve port of the pilot valve seat. A small hole is opened horizontally in the middle of the pilot valve seat, and the small hole is aligned with the horizontal through-hole on the pilot valve sleeve.

[0013] Furthermore, the through hole inside the locking sleeve is a stepped hole, the lower ball valve and the pilot return spring are located in the large hole at the upper end, and the small hole at the lower end is a damping hole.

[0014] Furthermore, the locking sleeve is connected to the threaded hole at the lower end of the pilot valve sleeve through an external thread.

[0015] Furthermore, it also includes a filter, which is inserted into the main valve core from the lower end of the main valve core.

[0016] Furthermore, the contact portion between the lower end of the main valve core and the interior of the valve body is conical or arc-shaped, correspondingly forming a cone valve or ball valve structure.

[0017] Compared with the prior art, the advantages of the present invention are:

[0018] When the existing pilot-operated safety valve is opened and unloaded, the main valve core control chamber is connected to the P port, which prevents the liquid in the control chamber from being discharged outward through the upper ball valve, thereby reducing the speed at which the main valve core moves upward and opens. During the opening process of the main valve core of the safety valve of the present invention, the upper control chamber (i.e., the chamber where the main reset spring is located) is separated from the P port, which can speed up the discharge of liquid from the control chamber and the speed at which the main valve core moves upward and opens. When closing, it not only relies on the spring force of the main reset spring, but also relies more on the pressure of the P port. The high-pressure liquid speeds up the downward closing speed of the main valve core. The present invention enables the opening and closing processes of the main valve core of the safety valve to exhibit a positive feedback promoting effect, and both the opening and closing processes are accelerated, thereby improving the overall response speed of the safety valve, reducing or even eliminating the accident rate of the hydraulic support due to the impact load, such as the expansion of the column cylinder, the explosion of the cylinder, and the penetration of the top, thereby ensuring the safe production of the coal mine comprehensive mining working face. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of the present invention.

[0020] In the figure: 1-valve body; 2-filter; 3-main valve core; 4-pilot return spring; 5-locking sleeve; 6-lower ball valve; 7-top rod; 8-pilot valve seat; 9-upper ball valve; 10-main return spring; 11-fastening screw; 12-pilot valve sleeve; 13-guide spring seat; 14-pressure regulating spring; 15-adjusting screw. DETAILED DESCRIPTION

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] like Figure 1 As shown: A hydraulic support positive feedback fast response safety valve includes a valve body 1, a main valve component, and a pilot valve component, wherein the pilot valve component is integrated into the main valve component; liquid outlets O are evenly arranged on the valve body 1, and the lower part of the valve body 1 is a liquid inlet P.

[0023] The main valve assembly includes a main valve core 3 and a main return spring 10. The main valve core 3 is slidingly and sealingly assembled in the valve body 1. The main return spring 10 uses the valve body 1 as support to push the main valve core 3 to block the passage between the liquid inlet and the liquid outlet on the valve body 1.

[0024] The main valve core 3 is hollow inside, and the pilot valve component is assembled on the valve body 1 and is slidingly sealed with the inner cavity of the main valve core 3. The main valve core control cavity is formed between the main valve core 3, the valve body 1 and the pilot valve component;

[0025] A main flow channel and a secondary flow channel are provided in the pilot valve component. The liquid inlet is connected to the valve body after passing through the inner cavity of the main valve core 3 and the main flow channel. The main flow channel includes a straight channel section. The upper port of the straight channel section is equipped with an upper ball valve 9, and the lower port is equipped with a lower ball valve 6. A push rod 7 is installed in the straight channel section. The upper ball valve 9, the lower ball valve 6 and the push rod 7 are arranged along the same axis. The upper ball valve 9 and the lower ball valve 6 are pushed toward the straight channel section by springs respectively. The length of the push rod 7 is greater than the length of the straight channel section. When the pressure at the liquid inlet is lower than the set pressure, the upper ball valve 9 blocks the upper port and the push rod 7 pushes the lower ball valve 6 to open the lower port; the secondary flow channel is located between the upper ball valve 9 and the lower ball valve 6, and the secondary flow channel is cross-connected with the straight channel section. The liquid inlet is connected to the main valve core control cavity after passing through the inner cavity of the main valve core 3, the main flow channel and the secondary flow channel.

[0026] Specifically, a threaded hole is provided at the lower end of the main valve core 3, and the filter 2 is inserted into the inside of the main valve core 3 from the lower end of the main valve core 3, and is installed and connected with the threaded hole at the lower end of the main valve core 3 by relying on the external thread at the lower end of the filter 2. The reason for setting the filter 3 is that there will be a large amount of iron filings and magazines inside the hydraulic support column due to reciprocating motion wear, which can easily clog the valve port of the pilot ball valve and require precise filtration.

[0027] The outer wall of the main valve core 3 contacts the inner wall of the valve body 1, and the inner wall of the main valve core 3 contacts the outer wall of the pilot valve sleeve 12. The main valve core 3 can slide in the vertical direction along the inner wall of the valve body 1 and the outer wall of the pilot valve sleeve 12 to control the opening and closing of the PO valve port; the upper end of the main valve core 3 is provided with an annular cavity, and the main reset spring 4 is provided in the annular cavity; the upper end surface of the main valve core 3, the inner wall of the valve body 1, and the wall of the pilot valve sleeve 12 constitute the main valve core control cavity; the contact point between the lower end of the main valve core 3 and the interior of the valve body is conical or arc-shaped, forming a cone valve or ball valve structure.

[0028] Specifically, the pilot valve components are composed of a pilot valve sleeve 12, a pilot return spring 4, a locking sleeve 5, a lower ball valve 6, a push rod 7, a pilot valve seat 8, an upper ball valve 9, a guide spring seat 13, a pressure-regulating spring 14, and an adjusting screw 15; the upper ball valve 9 and the lower ball valve 6 have exactly the same dimensions, and the upper ball valve 9, the lower ball valve 6, and the push rod 7 are arranged along the same axis.

[0029] The pilot valve sleeve 12 has a single-stage stepped hole at its upper end and a double-stage stepped hole at its lower end. The single-stage stepped hole and the double-stage stepped hole are interconnected. The first step of the single-stage stepped hole houses the upper ball valve 9, the guide spring seat 13, the pressure-regulating spring 14, and the adjusting screw 15. The upper portion of the first step of the single-stage stepped hole is threaded, and the adjusting screw 15 connects to the first step through this threaded structure. An oblique channel d is provided at the upper end of the single-stage stepped hole, connecting the first step hole to the outside.

[0030] A groove is provided on the lower end surface of the guide spring seat 13, and the upper ball valve 9 is placed inside the groove. A step is provided on the outer side of the spring seat 13, and an annular cavity is formed between the outer side of the spring seat 13 and the inner wall of the pilot valve sleeve 12. The pressure-regulating spring 14 is placed in the annular cavity between the adjusting screw 15 and the spring seat 13, and the two ends of the pressure-regulating spring 14 are respectively in contact with the adjusting screw 15 and the steps of the guide spring seat 13.

[0031] The locking sleeve 5 and the pilot valve seat 8 are installed in the two-step hole of the pilot valve sleeve 12 in sequence from bottom to top.

[0032] The mechanical limit surface of the locking sleeve 5 is in close contact with the first step surface of the two-step stepped hole, the upper end surface of the locking sleeve 5 is in close contact with the lower end surface of the pilot valve seat 8, and the locking sleeve 5 is connected to the threaded hole at the lower end of the pilot valve sleeve 12 through an external thread. A stepped hole is provided inside the locking sleeve 5. The lower ball valve 6 and the pilot return spring 4 are installed in the large hole at the upper end from top to bottom. The small hole at the lower end is a small damping hole a, which is used to prevent the pressure fluctuation of the main oil circuit of the system from affecting the stability of the pilot valve and the main valve.

[0033] The upper end surface of the pilot valve seat 8 is flush with the step surface of the single-stage stepped hole, and the mechanical limit surface of the pilot valve seat 8 is fitted with the second step surface of the two-stage stepped hole. A small hole is opened in the middle of the pilot valve seat 8 in the horizontal direction, and the small hole is aligned with the channel c on the pilot valve sleeve 12; a center hole is opened in the vertical direction inside the pilot valve seat 8, and the two ends of the center hole are the upper and lower valve ports. The upper ball valve 9 cooperates with the upper valve port of the pilot valve seat 8, and the lower ball valve 6 cooperates with the lower valve port of the pilot valve seat 8. The upper ball 9 is in the pressure regulating spring 14. Under the action of the pilot valve seat 8, it is tightly pressed on the upper valve port of the pilot valve seat 8 to close the valve port of the upper ball valve 9; the lower ball 6 is tightly pressed on the lower valve port of the pilot valve seat 8 under the action of the pilot return spring 4, and the push rod 7 is placed in the vertical center hole inside the pilot valve seat 8. The length of the push rod 7 must ensure that when the upper ball valve 9 is in the closed state, the valve port of the lower ball valve 6 is in the open state, and an annular gap channel b is formed between the push rod 7 and the vertical center hole inside the pilot valve seat 8, and the annular gap channel b is cross-connected with the horizontal transverse channel c.

[0034] Working principle:

[0035] Port P is connected to the lower chamber of the hydraulic support column. When the pressure at port P falls below the set pressure of pressure-regulating spring 14, upper ball valve 9, under the action of pressure-regulating spring 14, presses against the upper end face of pilot valve seat 8 via the guide spring seat, sealing the upper end of annular clearance channel b. Lower ball valve 6, under the action of push rod 7, remains open. Oil enters through inlet P, passes through the filter, and enters the lower ball valve port via damping orifice a. It then passes through annular clearance channel b and reaches upper ball valve 9. Annular clearance channel b intersects with horizontal transverse channel c, filling the control chamber at the upper end of main valve core 3. The entire oil level is at rest. The pressures at the upper and lower ends of main valve core 3 are equal, and the main return spring closes the main valve core 3, effectively closing unloading channel PO. When the pressure at port P exceeds the set pressure of pressure-regulating spring 14, the hydraulic pressure on upper ball valve 9 overcomes the set force of pressure-regulating spring 14, pushing it upward and opening the upper ball valve port. Simultaneously, the lower ball valve 6, under the action of pilot return spring 4, moves upward, closing the lower ball valve port. Liquid in the control chamber at the upper end of main valve core 3 (i.e., the chamber containing the main return spring) flows through transverse channel c and annular clearance channel b, then through the upper ball valve port, reaching the chamber containing the pressure-regulating spring and being discharged through channel d. This causes the liquid pressure in the control chamber at the upper end of main valve core 3 to drop, disrupting the original pressure balance of the main valve core and causing it to move upward. At this point, unloading channel PO is connected, and unloading begins in the lower chamber of the hydraulic support column. When the pressure in the lower chamber of the column is lower than the set pressure of the pressure-regulating spring 14 again, the upper ball valve 9 is closed again, the lower ball valve 6 is opened again, and the control chamber at the upper end of the main valve core 3 (i.e., the chamber where the main return spring is located) stops discharging liquid. The high-pressure liquid at port P flows through the damping hole a, the annular gap channel b and the transverse channel c and reaches the control chamber at the upper end of the main valve core 3. The combined action of the high-pressure liquid and the main return spring 10 causes the main valve core 3 to move downward, closing the unloading channel PO, and the column begins to bear the top plate load normally again.

[0036] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A positive feedback quick response safety valve for a hydraulic support, characterized by: It includes a valve body (1), a main valve component, and a pilot valve component; The main valve component includes a main valve core (3) and a main return spring (10); the main valve core (3) is slidingly and sealingly assembled in the valve body (1); the main return spring (10) pushes the main valve core (3) with the valve body (1) as support to block the passage between the liquid inlet and the liquid outlet on the valve body (1); The main valve core (3) is hollow inside, the pilot valve component is assembled on the valve body (1) and is slidably sealed with the inner cavity of the main valve core (3), and a main valve core control cavity is formed between the main valve core (3), the valve body (1) and the pilot valve component; A main flow channel and a secondary flow channel are provided in the pilot valve component. The liquid inlet is connected to the valve body after passing through the inner cavity of the main valve core (3) and the main flow channel. The main flow channel includes a straight channel section. The upper end of the straight channel section is equipped with an upper ball valve (9), and the lower end is equipped with a lower ball valve (6). A push rod (7) is installed in the straight channel section. The upper ball valve (9), the lower ball valve (6) and the push rod (7) are arranged along the same axis. The upper ball valve (9) and the lower ball valve (6) are pushed toward the straight channel section by springs respectively. The length of the push rod (7) is greater than the length of the straight channel section. When the pressure at the liquid inlet is lower than the set pressure, the upper ball valve (9) blocks the upper end, and the push rod (7) pushes the lower ball valve (6) to open the lower end. The secondary flow channel is located between the upper ball valve (9) and the lower ball valve (6). The secondary flow channel is cross-connected with the straight channel section. The liquid inlet is connected to the main valve core control chamber after passing through the inner cavity of the main valve core (3), the main flow channel and the secondary flow channel. The pilot valve component includes a pilot valve sleeve (12), the lower end of the pilot valve sleeve (12) is slidably sealed with the inner cavity of the main valve core (3), and the upper end is fastened to the valve body (1) by a fastening screw (11), and the main return spring (10) is sleeved on the lower end of the pilot valve sleeve (12), and the two ends of the main return spring (10) are respectively in contact with the upper end surface of the pilot valve sleeve (12) and the step surface of the inner cavity of the main valve core (3); the main flow channel and the secondary flow channel are integrated in the pilot valve sleeve (12); The pilot valve sleeve (12) is provided with a single-stage stepped hole at the upper end and a two-stage stepped hole at the lower end; the single-stage stepped hole and the two-stage stepped hole are connected; The first step hole of the single-stage stepped hole is provided with an upper ball valve (9), a guide spring seat (13), a pressure regulating spring (14), and an adjusting screw (15). The adjusting screw (15) is threadedly connected to the first step hole. A groove is provided on the lower end surface of the guide spring seat (13). The upper ball valve (9) is placed in the groove. A step is provided on the outer periphery of the guide spring seat (13). The pressure regulating spring (14) is placed between the adjusting screw (15) and the step of the guide spring seat (13). The cavity within the adjusting screw (15) in the first step hole is communicated with the outside. A locking sleeve (5) and a pilot valve seat (8) are sequentially installed in the two-stage stepped hole from bottom to top, a mechanical limit surface of the locking sleeve (5) is in close contact with the first step surface of the two-stage stepped hole, an upper end surface of the locking sleeve (5) is in close contact with the lower end surface of the pilot valve seat (8), a through hole is provided inside the locking sleeve (5), and a lower ball valve (6) and a pilot return spring (4) are sequentially installed in the through hole from top to bottom; The upper end surface of the pilot valve seat (8) is flush with the step surface of the single-stage stepped hole, and the mechanical limit surface of the pilot valve seat (8) is in contact with the second-stage step surface of the two-stage stepped hole; a center hole is opened in the vertical direction inside the pilot valve seat (8), and the push rod (7) is placed in the center hole. The two ends of the center hole are upper and lower valve ports, the upper ball valve (9) cooperates with the upper valve port of the pilot valve seat (8), and the lower ball valve (6) cooperates with the lower valve port of the pilot valve seat (8). A small hole is opened in the middle of the pilot valve seat (8) along the horizontal direction, and the small hole is aligned with the horizontal through-hole c on the pilot valve sleeve (12).

2. The positive feedback quick response safety valve of a hydraulic support according to claim 1, characterized in that: The through hole inside the locking sleeve (5) is a stepped hole, the lower ball valve (6) and the pilot return spring (4) are located in the large hole at the upper end, and the small hole at the lower end is a damping hole.

3. The positive feedback quick response safety valve for a hydraulic support according to claim 1, characterized in that: The locking sleeve (5) is connected to the threaded hole at the lower end of the pilot valve sleeve (12) via an external thread.

4. The positive feedback quick response safety valve for a hydraulic support according to claim 1, characterized in that: It also includes a filter (2), which is inserted into the main valve core (3) from the lower end of the main valve core (3).

5. The positive feedback quick response safety valve for a hydraulic support according to claim 1, characterized in that: The contact portion between the lower end of the main valve core (3) and the interior of the valve body (1) is conical or arc-shaped, correspondingly forming a cone valve or ball valve structure.

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