Double disc gate valve with improved seal

Abstract

The application relates to the technical field of gate valves, and particularly discloses a double-gate-plate gate valve with an improved sealing structure, which comprises a valve body, one side of the valve body is an upstream side, the other side of the valve body is a downstream side, the top of the valve body is provided with a valve cover, an upper sealing cover is arranged at the position where the valve body and the valve cover are internally connected, a connecting nut is fixedly installed at the top of the valve cover, a valve rod is in threaded connection with the inside of the connecting nut, and the bottom of the valve rod is provided with an opening-closing assembly comprising a side pressing block and two groups of connecting seats which are connected with each other. The opening-closing assembly is arranged, the first gate plate is matched with the first valve seat, the second gate plate is matched with the second valve seat, the double-side fourfold sealing when the valve is closed can be realized, the sealing property is improved, meanwhile, the connecting seat can be pressed by the side pressing block to enhance the sealing property when the valve is sealed, the hook structure formed between the side pressing block and the connecting seat can assist the two connecting seats to move close to the middle position, the required torque when the valve is opened is reduced, and the service life of the gate valve is prolonged.

Description

Technical Field

[0001] This invention relates to the field of gate valve technology, and in particular to a double gate valve with an improved sealing structure. Background Technology

[0002] As the name suggests, a double-gate valve consists of two independent gates instead of a single unit. Parallel double-gate valves offer good sealing performance. However, friction occurs between the gate and valve seat during opening and closing, which can cause wear and tear on the valve seat or gate over time, leading to media leakage. Furthermore, when a double-gate valve isolates a pipeline transporting liquid media, the liquid in the pipeline will thermally expand due to increased ambient temperature. Because the valve is closed, this expansion cannot be released, causing a sharp increase in pressure in the valve chamber and upstream pipeline. Since the liquid is incompressible, the high-pressure liquid pressure is not immediately released upon opening; the valve stem must continuously exert a significant force to push the gate until there is enough space for the liquid to depressurize. This process places a greater impact on the valve. Summary of the Invention

[0003] The purpose of this invention is to address the shortcomings of existing technologies by proposing a double gate valve with an improved sealing structure.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A double gate valve with an improved sealing structure includes a valve body, one side of the valve cavity on the valve body is the upstream side, the other side of the valve cavity is the downstream side, a valve cover is provided on the top of the valve body, an upper sealing cover is provided at the internal connection between the valve body and the valve cover, a connecting nut is fixedly installed on the top of the valve cover, a valve stem is connected to the internal thread of the connecting nut, and an opening and closing assembly including a side pressure block and two sets of interconnected connecting seats is provided at the bottom of the valve stem.

[0006] The side pressure block is fixedly installed at the bottom of the valve stem. Two sets of connecting seats are set on both sides of the side pressure block, corresponding to the upstream and downstream sides. A first gate is provided on the side of the connecting seat away from the side pressure block. The first gate is in contact with the connecting seat. A second gate is provided on the side of the first gate away from the connecting seat. The second gate is in contact with the first gate. A synchronization groove is opened on the side of the connecting seat near the side pressure block. The side pressure block is movably installed inside the synchronization groove. A notch is opened on the side of the side pressure block near the connecting seat. A synchronization plate is rotatably installed inside the notch. An auxiliary opening and closing assembly including a sealing plate is provided between the connecting seat and the first gate. A first valve seat is provided on the side of the connecting seat away from the side pressure block. A second valve seat is fixedly installed on the side of the first valve seat away from the connecting seat.

[0007] The sealing plate is slidably installed inside the first gate plate. A first pressure relief hole is opened at the center of the connecting seat, a second pressure relief hole is opened at the center of the first gate plate, a fourth pressure relief hole is opened at the center of the second gate plate, and a third pressure relief hole is opened on the sealing plate.

[0008] Preferably, the first valve seat is fixedly installed at the upstream and downstream ports inside the valve body, and the second valve seat is also fixedly installed at the upstream and downstream ports inside the valve body. The sealing surfaces of the first valve seat and the first gate, and the second gate and the second valve seat are all lined with sealing layers. Two positioning shafts are symmetrically fixedly installed inside the second valve seat, and positioning holes are opened on the second gate corresponding to the positions of the positioning shafts.

[0009] Preferably, the side pressure block consists of three parts: the first part is a cylindrical connecting shaft; the second part is two trapezoidal blocks with a cross-section that is wider at the top and narrower at the bottom, which are fixed outside the cylindrical connecting shaft; and the third part is two symmetrically arranged arc-shaped blocks fixed on the top of the trapezoidal blocks.

[0010] Preferably, the synchronization groove consists of three parts: the first part is a circular groove adapted to the cylindrical connecting shaft in the side pressure block; the second part is a right-angled trapezoidal groove with a cross-section that is wider at the top and narrower at the bottom and adapted to the trapezoidal block in the side pressure block; and the third part is a groove with a triangular cross-section that is opened at the top of the inner wall of the right-angled trapezoidal groove.

[0011] Preferably, the synchronization plate is rotatably mounted inside the recess via a rotating shaft, and a torsion spring is sleeved on the rotating shaft.

[0012] Preferably, a limiting plate is fixedly installed at the bottom of the connecting seat, and a guide shaft is provided between the two sets of limiting plates. The guide shaft passes through the two sets of limiting plates and extends to both sides of the limiting plates. A connecting spring is sleeved on the guide shaft, and the two ends of the connecting spring are fixedly connected to one end of the limiting plate and one end of the guide shaft, respectively.

[0013] Preferably, the auxiliary opening and closing assembly further includes a reset spring, which is fixedly installed on the side of the connecting seat near the first gate plate. The connecting seat has a fixing groove for installing the reset spring, and a positioning short shaft is fixedly installed inside the fixing groove. The positioning short shaft is sleeved with the reset spring.

[0014] Preferably, a mounting plate for connecting a reset spring is fixedly installed on the side of the sealing plate near the connecting seat. The mounting plate is fixedly connected to the upper end of the reset spring. An inner groove for installing the sealing plate is provided on the first gate plate. The sealing plate is slidably installed inside the inner groove.

[0015] Preferably, the auxiliary opening and closing assembly further includes a driving block, which is disposed between the sealing plate and the connecting seat. The two ends of the driving block are fixedly connected to the sealing plate and the connecting seat respectively. The connecting seat has a side groove, and the driving block is slidably installed inside the side groove. The side groove has a sliding groove, and the inside of the sliding groove communicates with the inside of the inner groove. The driving block is slidably installed inside the sliding groove.

[0016] Compared with the prior art, the beneficial effects of the present invention are:

[0017] This invention incorporates an opening and closing assembly. When the valve is closed, driven by the valve stem, the side pressure block, connecting seat, first gate, and second gate move to the corresponding first and second valve seats. During descent, the connecting seat, constrained by the connecting spring and the connecting seat, moves towards the side pressure block. After the connecting seat reaches its downward position, the side pressure block remains pressed down. Under the action of the side pressure block, the two sets of connecting seats can move towards the first and second valve seats until the second gate presses against the sealing surface of the second valve seat. The first gate presses against the sealing surface of the first valve seat. Through the cooperation of the first gate and the first valve seat, and the cooperation of the second gate and the second valve seat, a double-sided quadruple seal can be achieved when the valve is closed, improving sealing performance and reducing the possibility of liquid medium leakage. At the same time, the side pressure block can press the connecting seat to enhance sealing performance during sealing.

[0018] This invention incorporates an opening and closing assembly. When the valve is opened, the connecting seat moves upward, causing the side pressure block to move upward. During this upward movement, the connecting seat, under the influence of the side pressure block and the connecting spring, moves closer to the side pressure block. As the side pressure block continues to move, when the first gate separates from the first valve seat and the second gate separates from the second valve seat, and both sets of connecting seats reset, the upward movement of the side pressure block causes the connecting seat, the first gate, and the second gate to reset back into the valve cavity, at which point the valve is fully opened. When the valve is open, the hook structure formed between the side pressure block and the connecting seat helps the connecting seats on both sides move closer to the center position, reducing the torque required for valve opening. This also avoids friction caused by direct contact between the gate and the valve seat during valve opening and closing, improving valve performance and extending the valve's service life.

[0019] This invention incorporates an auxiliary opening and closing assembly. During valve opening and closing, the side pressure block, in conjunction with the connecting seat, drives the first gate and the second gate, in conjunction with the first and second valve seats, to open and close the valve. Furthermore, by utilizing the up-and-down movement of the sealing plate to drive the third pressure relief hole to overlap or stagger with the fourth, second, and first pressure relief holes, a pressure relief before opening and closing mechanism can be implemented. This reduces the pressure that the first and second gates must overcome during valve opening and closing, making valve opening and closing easier. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of a double gate valve with an improved sealing structure proposed in this invention;

[0021] Figure 2 This is a schematic diagram of the side pressure block in a double-gate valve with an improved sealing structure proposed in this invention;

[0022] Figure 3 for Figure 2 Enlarged view of point A in the middle;

[0023] Figure 4 This is a schematic diagram of the connecting seat in a double-gate valve with an improved sealing structure proposed in this invention;

[0024] Figure 5 This is a schematic diagram of the installation of the limit plate in a double-gate valve with an improved sealing structure proposed in this invention.

[0025] Figure 6 This is a schematic diagram of the opening and closing assembly in a double-gate valve with an improved sealing structure proposed in this invention.

[0026] Figure 7 This is a schematic diagram of the auxiliary opening and closing assembly in a double-gate valve with an improved sealing structure proposed in this invention.

[0027] Figure 8 This is a schematic diagram of the structure of the first gate in a double-gate valve with an improved sealing structure proposed in this invention;

[0028] Figure 9 This is a schematic diagram of the state when the first gate and the first gate seat of a double gate valve with an improved sealing structure proposed in this invention are not sealed.

[0029] Figure 10 This is a schematic diagram of the state when the first gate plate and the first gate seat of a double gate valve with an improved sealing structure proposed in this invention are in contact but the sealing plate is not pulled down.

[0030] Figure 11 This is a schematic diagram showing the state of a double gate valve with an improved sealing structure proposed in this invention, where the first gate plate is in contact with the first gate seat and the sealing plate is pulled down.

[0031] In the diagram: 1. Valve body; 11. Valve cover; 12. Connecting nut; 13. Valve stem; 14. Upper sealing cover; 2. Side pressure block; 21. Synchronizing plate; 22. Rotating shaft; 23. Torsion spring; 3. Connecting seat; 31. Limiting plate; 311. Guide shaft; 312. Connecting spring; 32. Synchronizing groove; 33. First pressure relief hole; 34. Side groove; 35. Drive block; 36. Return spring; 37. Positioning short shaft; 4. First gate plate; 41. Second pressure relief hole; 42. Sealing plate; 43. Mounting plate; 44. Inner groove; 45. Third pressure relief hole; 5. Second gate plate; 51. Fourth pressure relief hole; 52. Positioning hole; 6. First valve seat; 7. Second valve seat; 71. Positioning shaft. Detailed Implementation

[0032] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0033] Reference Figure 1-11A double-gate valve with an improved sealing structure includes a valve body 1, which is installed at a pipeline connection point during use. The valve body 1 connects two pipelines, with one side of the valve chamber on the upper part of the valve body 1 being the upstream side and the other side being the downstream side. The upstream side is the direction in which the medium enters the valve body 1, and the downstream side is the direction in which the medium exits the valve body 1. A valve cover 11 is provided on the top of the valve body 1, and the valve cover 11 is connected and fixed to the valve body 1 by fasteners. An upper sealing cover 14 is provided at the connection point between the valve body 1 and the valve cover 11, and the upper sealing cover 14 seals from the connection point. A connecting nut 12 is fixedly installed at the top of the valve cover 11, and a valve stem 13 is connected to the internal thread of the connecting nut 12. The valve stem 13 penetrates downward through the interior of the upper sealing cover 14 and... Extending downwards to the valve cavity on valve body 1, a pressure sensor is installed inside the valve cavity. The pressure sensor can be used to detect the pressure of the medium inside the valve cavity. The pressure sensor is electrically connected to an external PLC controller. A discharge pipe is installed inside the valve cavity on valve body 1, and a control valve is installed inside the discharge pipe. When the control valve is open, the medium inside the valve cavity can be discharged to the external recovery system through the discharge pipe. An opening and closing assembly is installed at the bottom of valve stem 13. The opening and closing assembly includes a side pressure block 2, which is fixedly installed at the bottom of valve stem 13. The side pressure block 2 consists of three parts: the first part is a cylindrical connecting shaft; the second part is two trapezoidal blocks with a cross-section that is wider at the top and narrower at the bottom, fixed outside the cylindrical connecting shaft; and the third part is two fixed... Symmetrically arranged arc-shaped blocks at the top of the trapezoidal block, connecting seats 3 are provided on both sides of the side pressure block 2, corresponding to the upstream and downstream positions. Limiting plates 31 are fixedly installed at the bottom of the connecting seats 3. A guide shaft 311 is provided between the two sets of limiting plates 31, passing through the two sets of limiting plates 31 and extending to both sides of the limiting plates 31. A connecting spring 312 is sleeved on the guide shaft 311, with both ends of the connecting spring 312 fixedly connected to one end of the limiting plate 31 and the guide shaft 311, respectively. When the valve is closed, the two sets of limiting plates 31 are moved apart, and the connecting spring 312 is stretched. When the valve is opened, the two sets of limiting plates 31 move towards each other, and the connecting spring 312 returns to its original position. A first gate 4 is provided on the side of the connecting seat 3 away from the side pressure block 2. The first gate plate 4 is fitted with the connecting seat 3. A second gate plate 5 is provided on the side of the first gate plate 4 away from the connecting seat 3. The second gate plate 5 is fitted with the first gate plate 4, and the outer diameter of the second gate plate 5 is smaller than the outer diameter of the first gate plate 4. A synchronization groove 32 is provided on the side of the connecting seat 3 near the side pressure block 2. The side pressure block 2 is movably installed inside the synchronization groove 32. The synchronization groove 32 consists of three parts: the first part is a circular groove that matches the cylindrical connecting shaft in the side pressure block 2; the second part is a right-angled trapezoidal groove with a wider top and narrower bottom cross-section that matches the trapezoidal block in the side pressure block 2 and is located at the top of the inner wall of the circular groove; the third part is a groove with a triangular cross-section located at the top of the inner wall of the right-angled trapezoidal groove. When the valve is closed, the side pressure block 2 moves downward.The trapezoidal block in side pressure block 2 can compress the right-angled trapezoidal groove wall in connecting seat 3. As side pressure block 2 continues to move downwards, it drives the two sets of connecting seats 3 to move relative to each other, enhancing sealing. When the valve is closed, side pressure block 2 moves upwards, causing the two sets of connecting seats 3 to move relative to each other. The arc-shaped block in side pressure block 2 and the triangular groove in connecting seat 3 can form a hook structure, helping the two sets of connecting seats 3 to move inwards and reset, reducing the torque required to open the valve. A notch is provided on the side of side pressure block 2 near the connecting seat 3. A synchronous plate 21 is rotatably installed inside the notch. The synchronous plate 21 is rotatably installed inside the notch via a rotating shaft 22. A torsion spring 23 is sleeved on the rotating shaft 22. An auxiliary opening and closing assembly is provided between the connecting seat 3 and the first gate plate 4. The components help relieve pressure when the valve is opened and closed, reducing resistance and extending valve life. A first valve seat 6 is located on the side of the connecting seat 3 away from the side pressure block 2. The first valve seat 6 is fixedly installed inside the valve body 1 at the upstream and downstream ports that are close to each other. When the valve is closed, the first gate 4 can fit against the annular surface of the first valve seat 6 near the connecting seat 3. A second valve seat 7 is fixedly installed on the side of the first valve seat 6 away from the connecting seat 3. The internal diameter of the second valve seat 7 is smaller than that of the first valve seat 6. The second valve seat 7 is also fixedly installed inside the valve body 1 at the upstream and downstream ports that are close to each other. The sealing surfaces of the first valve seat 6 and the first gate 4, and the second gate 5 and the second valve seat 7, are all lined with a sealing layer (the sealing layer can be made of rubber). When the valve is closed, the second gate 5 can fit against the annular surface of the second valve seat 7 near the connecting seat 3. When the valve is closed, the first gate 4 and the first valve seat 6 are sealed together, and the second gate 5 and the second valve seat 7 are sealed together to form a double sealing structure, which improves the sealing effect. Two positioning shafts 71 are symmetrically fixedly installed inside the second valve seat 7. Positioning holes 52 are opened on the second gate 5 at the positions corresponding to the positioning shafts 71, and the positioning shafts 71 can be inserted into the positioning holes 52. With the opening and closing assembly, when the valve is opened and closed, it is driven by the valve stem 13, and the side pressure block 2, the connecting seat 3, the first gate 4 and the second gate 5 move to the corresponding positions of the first valve seat 6 and the second valve seat 7. During the descent, the connecting seat 3 moves towards the side pressure block 2 under the constraint of the connecting spring 312 and the connecting seat 3. After the connecting seat 3 moves downwards to its position, the side pressure block 2 remains pressed down. Under the action of the side pressure block 2, the two sets of connecting seats 3 can move towards the side closer to the first valve seat 6 and the second valve seat 7 until the second gate 5 presses against the sealing surface of the second valve seat 7, and the first gate 4 presses against the sealing surface of the first valve seat 6. Through the cooperation of the first gate 4 and the first valve seat 6, and the cooperation of the second gate 5 and the second valve seat 7, a double-sided quadruple seal can be achieved when the valve is closed, improving the sealing performance and reducing the possibility of liquid medium leakage. At the same time, the side pressure block 2 can press the connecting seat 3 to enhance the sealing performance during sealing. When the valve is opened, the connecting seat 3 moves upwards, causing the side pressure block 2 to move upwards. During the upward movement of the side pressure block 2, the connecting seat 3 moves towards the side closer to the side pressure block 2 under the action of the side pressure block 2 and the connecting spring 312.During the continuous movement of the side pressure block 2, when the first gate 4 separates from the first valve seat 6, and the second gate 5 separates from the second valve seat 7, and the two sets of connecting seats 3 reset, the side pressure block 2 moves upward, causing the connecting seats 3, the first gate 4, and the second gate 5 to reset inside the valve cavity. At this point, the valve is fully opened. When the valve is open, the hook structure formed between the side pressure block 2 and the connecting seats 3 helps the connecting seats 3 on both sides to move towards the center, reducing the torque required for valve opening. This also avoids friction caused by direct contact between the gate and the valve seat during valve opening and closing, improving valve performance and extending the gate's service life.

[0034] As an optimized solution for a double-gate valve with an improved sealing structure according to the present invention, the auxiliary opening and closing assembly includes a return spring 36. The return spring 36 is fixedly installed on the side of the connecting seat 3 near the first gate 4. The connecting seat 3 has a fixing groove for installing the return spring 36. A positioning short shaft 37 is fixedly installed inside the fixing groove. The positioning short shaft 37 is sleeved with the return spring 36. A first pressure relief hole 33 is opened at the center of the connecting seat 3. A second pressure relief hole 41 is opened at the center of the first gate 4. A fourth pressure relief hole 51 is opened at the center of the second gate 5. In the initial state, the centers of the first pressure relief hole 33, the second pressure relief hole 41, and the fourth pressure relief hole 51 are on the same horizontal line. A sealing plate 42 is slidably installed inside the first gate plate 4. A mounting plate 43 is fixedly installed on the side of the sealing plate 42 near the connecting seat 3. The mounting plate 43 is fixedly connected to the upper end of the return spring 36. An inner groove 44 for installing the sealing plate 42 is provided on the first gate plate 4. The sealing plate 42 is slidably installed inside the inner groove 44. A third pressure relief hole 45 is provided on the sealing plate 42. In the initial state, the centers of the third pressure relief hole 45 and the second pressure relief hole 41 are on the same horizontal line. Online, a driving block 35 is provided between the sealing plate 42 and the connecting seat 3. The two ends of the driving block 35 are fixedly connected to the sealing plate 42 and the connecting seat 3 respectively. The connecting seat 3 has a side groove 34, which is an H-shaped groove. The driving block 35 is slidably installed inside the side groove 34. The side groove 34 has a sliding groove, which is connected to the inside of the inner groove 44. The driving block 35 is slidably installed inside the sliding groove. When the driving block 35 moves downward and slides to contact the bottom of the inner wall of the side groove 34, the third pressure relief hole 45 on the sealing plate 42 and the second pressure relief hole 45 on the first gate plate 4 are connected. 1. The valve is closed by staggering the opening and closing mechanism. With the auxiliary opening and closing components, when the valve is opened and closed, the side pressure block 2 and the connecting seat 3 drive the first gate 4 and the second gate 5 to work with the first valve seat 6 and the second valve seat 7 to realize the opening and closing of the valve. When the valve is opened and closed, by using the up and down movement of the sealing plate 42 to drive the third pressure relief hole 45 to coincide with or stagger the fourth pressure relief hole 51, the second pressure relief hole 41 and the first pressure relief hole 33, the valve can be opened and closed by first relieving pressure and then opening and closing, which reduces the pressure that the first gate 4 and the second gate 5 have to overcome when the valve is opened and closed, making the valve opening and closing easier.

[0035] When using this invention:

[0036] When the valve is closed: Rotate the handwheel connected to the outside of the valve stem 13. When the valve stem 13 rotates, it is threadedly connected to the connecting nut 12 and moves downward inside the valve cavity. When the valve stem 13 moves downward, it drives the side pressure block 2 to move downward to the middle position of the upper and lower sides of the valve cavity. During the movement, the connecting seat 3 moves towards the middle position under the action of the connecting spring 312 and the side pressure block 2. When the connecting seat 3 moves to the bottom of the connecting spring 312 and the bottom of the inner wall of the valve body 1, the side pressure block 2 squeezes the connecting seats 3 on both sides. The connecting seats 3 on both sides change from a state of vertical movement along the axial direction of the side pressure block 2 to a state of horizontal movement perpendicular to the side pressure block 2. At this time, the first gate plate 4 and the second gate plate 5 move towards the first valve seat 6 and the second valve seat 7 (see the schematic diagram for the specific state). Figure 9 (as shown)

[0037] In this state, the centers of the first pressure relief hole 33 on the connecting seat 3, the second pressure relief hole 41 on the first gate plate 4, the third pressure relief hole 45 on the sealing plate 42, and the fourth pressure relief hole 51 on the second gate plate 5 are all on the same horizontal line. During the continuous downward movement of the side pressure block 2 to press the connecting seat 3, the trapezoidal block in the side pressure block 2 presses against the right-angled trapezoidal groove wall in the synchronous groove 32 to drive the first gate plate 4 to stick tightly to the first valve seat 6, and the second gate plate 5 to stick tightly to the second valve seat 7 (see the schematic diagram for the specific state). Figure 10 (As shown), after being tightly fitted, the centers of the first pressure relief hole 33, the second pressure relief hole 41, the third pressure relief hole 45, and the fourth pressure relief hole 51 remain on the same horizontal line. The liquid medium inside the pipe continues to flow from the first pressure relief hole 33, the second pressure relief hole 41, the third pressure relief hole 45, and the fourth pressure relief hole 51 into the valve cavity. The side pressure block 2 continues to press down. When the trapezoidal block in the side pressure block 2 passes through the right-angled trapezoidal groove in the synchronization groove 32, the arc-shaped block installed on the top of the trapezoidal block in the side pressure block 2 moves into the circular groove in the synchronization groove 32. At this time, the side pressure block 2 no longer squeezes the connecting seat 3, and the first gate plate 4 and the second gate plate 5 no longer move horizontally. Synchronously, the synchronization plate 21 rotates away from the side pressure block 2 and into the side groove 34 under the action of the torsion spring 23. When the side pressure block 2 continues to move downward, the synchronization plate 21 generates downward pressure on the drive block 35 and drives the sealing plate 42 to move downward (see the specific state diagram). Figure 11As shown), the downward movement of the sealing plate 42 only requires overcoming the friction between the sealing plate 42 and the first gate 4, as well as part of the liquid medium force. Since the force-bearing area of ​​the sealing plate 42 is small, the liquid medium force can be effectively reduced. The third pressure relief hole 45 on the sealing plate 42 is no longer on the same horizontal line as the second pressure relief hole 41, the fourth pressure relief hole 51 and the first pressure relief hole 33. At this time, the liquid medium inside the pipe of the first gate 4 is sealed and no longer passes through the first pressure relief hole 33, the second pressure relief hole 41, the fourth pressure relief hole 51 and the third pressure relief hole 45. The valve is closed.

[0038] When the valve is opened: the valve stem 13 is rotated in the reverse direction, and the side pressure block 2 moves upward. At this time, the shaving-shaped block in the side pressure block 2 moves upward in the circular groove of the synchronous groove 32 and moves into the groove with a right-angled trapezoidal cross section in the synchronous groove 32. At this time, the sealing plate 42 moves upward to reset. When the sealing plate 42 moves upward, it only needs to overcome the friction between itself and the first gate plate 4 and the force of the liquid medium. The third pressure relief hole 45 coincides with the first pressure relief hole 33, the second pressure relief hole 41 and the fourth pressure relief hole 51 again. At this time, the liquid medium on the upstream side flows into the valve cavity through the fourth pressure relief hole 51, the third pressure relief hole 45, the second pressure relief hole 41 and the first pressure relief hole 33 on the upstream side, and is then discharged by the valve. The pressure flows from the cavity to the downstream side through the first pressure relief hole 33, the second pressure relief hole 41, the third pressure relief hole 45, and the fourth pressure relief hole 51. At this time, the pressure on the upstream side, the valve cavity, and the downstream side is the same. The side pressure block 2 continues to move upward. When the side pressure block 2 moves upward to the point where the arc-shaped block in the side pressure block 2 contacts the triangular groove in the synchronous groove 32, the arc-shaped block in the side pressure block 2 and the triangular groove in the connecting seat 3 can form a hook structure to help the two sets of connecting seats 3 move inward to reset. After the connecting seat 3 is reset under the action of the connecting spring 312 and the hook structure, the side pressure block 2 moves upward and drives the connecting seat 3 to move into the valve cavity, and the valve is opened.

[0039] The specific flow direction of the medium during valve opening and closing is as follows:

[0040] When the valve is not closed: the medium flows from the upstream side to the downstream side;

[0041] During valve closure: The medium flows from the upstream side to the downstream side. At this time, the valve stem 13 moves downward, and the first gate 4 and the first valve seat 6, and the second gate 5 and the second valve seat 7 are in contact and closed. Since the positions of the first pressure relief hole 33, the second pressure relief hole 41, the third pressure relief hole 45 and the fourth pressure relief hole 51 coincide at this time, the medium flow direction is: upstream side - the first pressure relief hole 33, the second pressure relief hole 41, the third pressure relief hole 45 and the fourth pressure relief hole 51 on the upstream side - valve cavity - downstream side. The first pressure relief hole 33, the second pressure relief hole 41, the third pressure relief hole 45 and the fourth pressure relief hole 51 on the downstream side - downstream side;

[0042] Subsequently, the sealing plate 42 was pulled down, and the third pressure relief hole 45 was offset from the first pressure relief hole 33, the second pressure relief hole 41, and the fourth pressure relief hole 51, completely isolating the upstream and downstream from the valve cavity, and the medium was cut off from flowing.

[0043] When the valve is opened: the sealing plate 42 is pulled open first. At this time, the positions of the first pressure relief hole 33, the second pressure relief hole 41, the third pressure relief hole 45 and the fourth pressure relief hole 51 overlap again, and the isolated medium flows again. It still flows from the upstream side - the first pressure relief hole 33, the second pressure relief hole 41, the third pressure relief hole 45 and the fourth pressure relief hole 51 on the upstream side - the valve chamber - the first pressure relief hole 33, the second pressure relief hole 41, the third pressure relief hole 45 and the fourth pressure relief hole 51 on the downstream side - downstream side;

[0044] Then the valve stem 13 continues to pull upward, and the first gate 4 and the second gate 5 move upward and reset. At this time, the direction of medium flow is upstream side to downstream side.

[0045] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

[0046] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A double-gate valve with an improved sealing structure, comprising a valve body (1), wherein one side of the valve cavity on the valve body (1) is the upstream side and the other side of the valve cavity is the downstream side, a valve cover (11) is provided on the top of the valve body (1), an upper sealing cover (14) is provided at the internal connection between the valve body (1) and the valve cover (11), a connecting nut (12) is fixedly installed at the top of the valve cover (11), and a valve stem (13) is internally threaded into the connecting nut (12), characterized in that: The bottom of the valve stem (13) is provided with an opening and closing assembly including a side pressure block (2) and two sets of interconnected connecting seats (3); The side pressure block (2) is fixedly installed at the bottom of the valve stem (13). Two sets of connecting seats (3) are set on both sides of the side pressure block (2) corresponding to the upstream and downstream sides. A first gate (4) is provided on the side of the connecting seat (3) away from the side pressure block (2), and the first gate (4) is in contact with the connecting seat (3). A second gate (5) is provided on the side of the first gate (4) away from the connecting seat (3), and the second gate (5) is in contact with the first gate (4). An opening is provided on the side of the connecting seat (3) close to the side pressure block (2). There is a synchronization groove (32), and a side pressure block (2) is movably installed inside the synchronization groove (32). A notch is opened on the side of the side pressure block (2) near the connecting seat (3). A synchronization plate (21) is rotatably installed inside the notch. An auxiliary opening and closing assembly including a sealing plate (42) is provided between the connecting seat (3) and the first gate (4). A first valve seat (6) is provided on the side of the connecting seat (3) away from the side pressure block (2). A second valve seat (7) is fixedly installed on the side of the first valve seat (6) away from the connecting seat (3). The sealing plate (42) is slidably installed inside the first gate plate (4). A first pressure relief hole (33) is provided at the center of the connecting seat (3), a second pressure relief hole (41) is provided at the center of the first gate plate (4), a fourth pressure relief hole (51) is provided at the center of the second gate plate (5), and a third pressure relief hole (45) is provided on the sealing plate (42).

2. A double-gate valve with an improved sealing structure according to claim 1, characterized in that: The first valve seat (6) is fixedly installed at the port on the upstream and downstream sides of the valve body (1) that are close to each other. The second valve seat (7) is also fixedly installed at the port on the upstream and downstream sides of the valve body (1) that are close to each other. The sealing surfaces of the first valve seat (6) and the first gate (4), and the second gate (5) and the second valve seat (7) are all lined with a sealing layer. Two positioning shafts (71) are symmetrically fixedly installed inside the second valve seat (7). Positioning holes (52) are opened on the second gate (5) at the positions corresponding to the positioning shafts (71).

3. A double-gate valve with an improved sealing structure according to claim 1, characterized in that: The side pressure block (2) consists of three parts: the first part is a cylindrical connecting shaft, the second part is two trapezoidal blocks with a cross-section that is wider at the top and narrower at the bottom, which are fixed outside the cylindrical connecting shaft, and the third part is two symmetrically arranged arc-shaped blocks fixed on the top of the trapezoidal blocks.

4. A double-gate valve with an improved sealing structure according to claim 1, characterized in that: The synchronization groove (32) consists of three parts: the first part is a circular groove that is adapted to the cylindrical connecting shaft in the side pressure block (2); the second part is a right-angled trapezoidal groove with a cross-section that is wider at the top and narrower at the bottom and adapted to the trapezoidal block in the side pressure block (2); and the third part is a groove with a triangular cross-section that is opened at the top of the inner wall of the right-angled trapezoidal groove.

5. A double-gate valve with an improved sealing structure according to claim 1, characterized in that: The synchronization plate (21) is rotatably mounted inside the recess via a rotating shaft (22), and a torsion spring (23) is sleeved on the rotating shaft (22).

6. A double-gate valve with an improved sealing structure according to claim 1, characterized in that: The bottom of the connecting seat (3) is fixedly installed with a limiting plate (31). A guide shaft (311) is provided between the two sets of limiting plates (31). The guide shaft (311) passes through the two sets of limiting plates (31) and extends to both sides of the limiting plates (31). A connecting spring (312) is sleeved on the guide shaft (311). The two ends of the connecting spring (312) are fixedly connected to one end of the limiting plate (31) and the guide shaft (311), respectively.

7. A double-gate valve with an improved sealing structure according to claim 1, characterized in that: The auxiliary opening and closing assembly also includes a reset spring (36). The reset spring (36) is fixedly installed on the side of the connecting seat (3) near the first gate plate (4). The connecting seat (3) has a fixing groove for installing the reset spring (36). A positioning short shaft (37) is fixedly installed inside the fixing groove. The positioning short shaft (37) is sleeved with the reset spring (36).

8. A double-gate valve with an improved sealing structure according to claim 7, characterized in that: The sealing plate (42) is fixedly installed with a mounting plate (43) for connecting the reset spring (36) on the side near the connecting seat (3). The mounting plate (43) is fixedly connected to the upper end of the reset spring (36). The first gate plate (4) has an inner groove (44) for installing the sealing plate (42). The sealing plate (42) is slidably installed inside the inner groove (44).

9. A double-gate valve with an improved sealing structure according to claim 8, characterized in that: The auxiliary opening and closing assembly also includes a drive block (35), which is disposed between the closing plate (42) and the connecting seat (3). The two ends of the drive block (35) are fixedly connected to the closing plate (42) and the connecting seat (3) respectively. A side groove (34) is provided on the connecting seat (3). The drive block (35) is slidably installed inside the side groove (34). A sliding groove is provided on the side groove (34). The inside of the sliding groove is connected to the inside of the inner groove (44). The drive block (35) is slidably installed inside the sliding groove.

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