Gate valve

Abstract

A fluid channel is arranged in a valve body, and a valve seat is arranged on the side wall of the valve body between a first channel and a second channel of the fluid channel. The double-flashboard assembly comprises a first flashboard and a second flashboard which are movably connected together, and an elastic piece is arranged between the first flashboard and the second flashboard. The valve rod is connected with the double-gate-plate assembly and can drive the double-gate-plate assembly to move. When the double-gate plate assembly moves to be in complete sealing contact with the valve seat, a cavity is formed between the first gate plate and the second gate plate. The bypass assembly comprises a third connecting pipe and further comprises a first connecting pipe and / or a second connecting pipe; a pipeline connected with the third connecting pipe and the first connecting pipe can enable a medium in the first channel to flow into the cavity in a one-way manner; and / or a pipeline connected with the third connecting pipe and the second connecting pipe can enable the medium in the second channel to flow into the cavity in a one-way manner. Opening and closing torque of the gate valve can be effectively reduced, abrasion of a sealing face is reduced, and the service life of the gate valve is prolonged.

Description

Technical Field

[0001] This utility model relates to the field of valve technology, and more specifically, to a gate valve. Background Technology

[0002] A gate valve is a valve with a gate as its opening and closing element. Its movement direction is perpendicular to the water flow direction. Its function is to cut off or connect the medium in the pipeline. It is a type of valve that is always in one of two states: closed or fully open.

[0003] CN221525595U discloses a gate valve, including a valve body, a valve plate, a valve stem, and a valve handle. The valve plate is located inside the valve body, and its top is fixed to the valve handle. Rotating a handwheel causes the valve stem nut to rotate, which in turn moves the valve stem upwards or downwards, thereby moving the valve plate and opening or closing the gate valve. To improve sealing, sealing material, such as metal, is typically welded onto the sealing surfaces of the valve body sealing seat and the valve plate to increase wear resistance. Furthermore, the sealing surfaces are angled, as shown in this prior art solution, being wider at the top and narrower at the bottom. This angled design increases the force on the sealing surface as the valve plate moves downwards to close, thus ensuring sealing performance.

[0004] Because the sealing surface is made of welded metal, the dimensional accuracy of the mating between the valve seat and the valve plate directly reflects the sealing performance of the gate valve. However, in actual production, due to the objective existence of production equipment and manufacturing errors, a large closing pressure needs to be applied to the valve plate to compensate for the mating error, until the sealing surfaces of the valve seat and valve plate undergo elastic deformation to achieve effective closure. This results in a large closing torque and significant wear on the sealing surface, which can easily lead to fluid leakage after prolonged operation. Moreover, to overcome the elastic deformation caused by the large torque, the valve body is designed with increased wall thickness to reduce the impact on the valve body itself.

[0005] In summary, existing gate valves have the following disadvantages: 1. Poor sealing performance; 2. Difficult to manufacture, especially large-diameter gate valves; 3. Thick valve body walls, resulting in high material costs; 4. High opening and closing torque, requiring high-performance actuators that are easily damaged, leading to high actuator costs; 5. High overall installation height, occupying a large space, etc. Summary of the Invention

[0006] This invention provides a gate valve that can reduce the opening and closing torque of the gate valve, reduce the wear of the sealing surface, improve the sealing performance, and increase the service life of the gate valve.

[0007] To achieve the above objectives, the technical solution provided by this utility model is as follows:

[0008] A gate valve, comprising:

[0009] A valve body has a fluid channel inside, the fluid channel including a first channel and a second channel, and valve seats are provided on the valve body sidewalls that are close to each other in the first channel and the second channel;

[0010] Also includes:

[0011] A dual-gate assembly includes a first gate and a second gate that are movably connected together, and at least one elastic element is provided between the first gate and the second gate for applying an elastic force to the first gate and the second gate.

[0012] The valve stem has one end located outside the valve body and the other end extending into the valve body and connected to the double gate assembly. It can drive the double gate assembly to reciprocate along the valve stem direction to control the opening and closing of the fluid channel. When the double gate assembly moves to seal against the valve seat and closes the fluid channel, a chamber is formed between the first gate and the second gate.

[0013] The bypass assembly includes a third connecting pipe, and also includes a first connecting pipe and / or a second connecting pipe;

[0014] The third connecting pipe is connected to the first connecting pipe, and a first check valve is provided on the connecting pipe, allowing the medium in the first channel to flow unidirectionally into the chamber through the connecting pipe; and / or, the third connecting pipe is connected to the second connecting pipe, and a second check valve is provided on the connecting pipe, allowing the medium in the second channel to flow unidirectionally into the chamber through the connecting pipe.

[0015] In this design, an elastic element is also provided between the first gate and the second gate to form an elastic double gate assembly. At the same time, a bypass assembly is connected to the valve body to allow the fluid medium to flow unidirectionally into the chamber between the first gate and the second gate, which has a fluid self-sealing effect, reduces the opening and closing torque of the gate valve, reduces the wear of the sealing surface, and improves the sealing performance, thereby increasing the service life of the gate valve.

[0016] As a further improvement, the bypass assembly also includes a tee fitting; the first connecting pipe is connected to the third connecting pipe through the tee fitting, and the second connecting pipe is connected to the third connecting pipe through the tee fitting.

[0017] As a further improvement, the elastic element includes a first elastic element and a second elastic element, which are symmetrically arranged on both sides of the axial center line of the valve stem, so that the gate plate is subjected to the same force on both sides of the valve stem, avoiding the reduction of the sealing effect of the gate plate due to different forces.

[0018] As a further improvement, the first and second gates are inclined so that the size of the chamber between the first and second gates gradually decreases in the direction away from the valve stem, so that the double gate assembly forms a wedge-shaped structure that is wider at the top and narrower at the bottom. When the gate valve is opened, the inclined gates can guide the fluid and reduce the impact of the fluid on the gates.

[0019] As a further improvement, the first gate and the second gate are movably connected by a hook assembly;

[0020] The hook assembly includes a first left hook and a second left hook connected to the first gate, and a first right hook and a second right hook connected to the second gate;

[0021] The first left hook and the first right hook are connected, and the second left hook and the second right hook are connected. Furthermore, there are gaps at the connection points of the first left hook and the first right hook, as well as at the connection points of the second left hook and the second right hook, to provide space for the first and second gates to move closer or further apart. The hook assembly is also connected with an elastic element to prevent the first and second gates from disengaging, while also providing elasticity to the dual-gate assembly.

[0022] As a further improvement, two of each of the first left hook and the first right hook are provided, symmetrically located on both sides of the second left hook and the second right hook. This creates a relatively stable triangle between the connection points of the second left hook and the second right hook, and between the connection points of the first left hook and the first right hook.

[0023] As a further improvement, the hook opening directions of the first left hook and the second left hook are opposite, and the hook opening directions of the first right hook and the second right hook are opposite, so as to prevent the hook assembly from disengaging when the double gate assembly moves along the valve stem.

[0024] As a further improvement, a valve stem nut is threaded onto the valve stem, and the valve stem nut is located between and connected to the second left hook and the second right hook. Rotation of the valve stem causes the valve stem nut to move along the valve stem, simultaneously moving the double gate assembly. Positioning the valve stem nut between the second left hook and the second right hook, allowing it to sink into the space occupied by the double gate assembly, reduces the installation height of the gate valve, thereby reducing the space occupied by the gate valve in terms of height.

[0025] As a further improvement, a sealing surface is provided at the edge of the first gate and the second gate, the sealing surface being used for a sealing connection with the valve seat.

[0026] As a further improvement, a valve body opening is provided on one side of the valve body, and a valve cover is provided over the valve body opening, with the valve stem passing through the valve cover.

[0027] Other technical problems that the gate valve of this utility model can solve, other technical features contained in the technical solution, and the advantages brought by these technical features will be further explained in detail with reference to the accompanying drawings. Attached Figure Description

[0028] Figure 1 This is the main view of the gate valve;

[0029] Figure 2 for Figure 1 Cross-sectional view of the gate valve from the rear view direction;

[0030] Figure 3 This is a schematic diagram of the bypass component structure;

[0031] Figure 4 This is a schematic diagram showing the connection state between the first and second gates.

[0032] Figure 5 for Figure 4 Cross-sectional view from a low angle;

[0033] Figure 6 A three-dimensional schematic diagram showing the connection state of the first gate, the second gate, and the valve stem;

[0034] Figure 7 Another perspective three-dimensional schematic diagram of the connection state of the first gate, the second gate, and the valve stem;

[0035] Figure 8 A three-dimensional schematic diagram of the first gate, the second gate, and the valve stem;

[0036] Figure 9 This is a schematic diagram from another angle showing the connection state of the first and second gates.

[0037] Label Explanation:

[0038] 1. Valve body; 11. First channel; 12. Second channel; 13. Valve seat; 14. Valve body opening;

[0039] 2. Valve cover;

[0040] 3. Bypass assembly; 31. First connecting pipe; 32. Second connecting pipe; 33. Third connecting pipe; 34. Tee; 35. First check valve; 36. Second check valve;

[0041] 41. First gate; 411. First left hook; 412. Second left hook; 42. Second gate; 421. First right hook; 422. Second right hook; 423. Sealing surface; 424. Positioning groove; 43. Valve stem; 431. Valve stem nut; 4311. Upper limit block; 4312. Lower limit block; 432. Actuator; 44. First elastic element; 45. Second elastic element; 46. Chamber;

[0042] 5. Sealing components. Detailed Implementation

[0043] To further understand the content of this utility model, a detailed description of this utility model will be provided in conjunction with the accompanying drawings and embodiments.

[0044] The structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the implementation conditions of this utility model. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and purposes that this utility model can produce, should still fall within the scope of the technical content disclosed in this utility model.

[0045] Furthermore, terms such as "upper," "lower," "left," "right," and "middle" used in this specification are merely for clarity of description and not intended to limit the scope of implementation. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of this utility model. In addition to indicating orientation or positional relationships, some of the aforementioned terms may also have other meanings; for example, the term "upper" may, in certain circumstances, indicate a dependency or connection. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0046] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate for the embodiments of this application described herein.

[0047] Gate valves are installed in fluid media pipeline systems. The gate in a gate valve moves in a direction perpendicular to the flow direction of the fluid inside it, and the flow of the medium in the pipeline is cut off or connected by the gate.

[0048] Combination Figure 1-3 As shown, this embodiment provides a gate valve, including a valve body 1, a double gate assembly, a valve stem 43, and a bypass assembly 3.

[0049] The valve body 1 has a fluid passage, including a first passage 11 and a second passage 12. Valve seats 13 are installed on the valve body sidewalls of the first and second passages 11 and 12, which are close to each other. The gate valve is installed in a pipeline system. The first passage 11 and the second passage 12 are connected to the pipeline, and fluid flows through the fluid passages. A valve body opening 14 is also provided on one side of the valve body 1, and a valve cover 2 is installed over the valve body opening 14. To improve the sealing performance of the valve cover 2 over the valve body opening 14, an elastic sealing ring is embedded on the side of the valve cover 2 that contacts the valve body 1.

[0050] The dual-gate assembly includes a first gate 41 and a second gate 42 movably connected together. An elastic element is also provided between the first gate 41 and the second gate 42 for applying an elastic force to the first gate 41 and the second gate 42. Preferably, the elastic element is a spring, with its two ends connected to the first gate 41 and the second gate 42, respectively.

[0051] A valve stem 43 passes through the valve cover 2. One end of the valve stem 43 is located outside the valve body 1, and the other end extends through the valve cover 2 into the valve body 1 and connects to the double gate assembly. This double gate assembly can reciprocate along the valve stem 43 to control the opening and closing of the fluid passage. Specifically, the end of the valve stem 43 located outside the valve body 1 is connected to an actuator 432. The actuator 432 drives the valve stem 43 to rotate, thereby moving the double gate assembly. The actuator 432 can be a motor or a hydraulic cylinder, etc.

[0052] When the valve stem 43 moves the double gate assembly away from the fluid passage, the fluid passage opens, allowing the medium to flow. When the valve stem 43 moves the double gate assembly to the first passage 11 and the second passage 12, and the double gate assembly is in sealing contact with the valve seat 13, the fluid passage closes, and the flow of the medium is cut off. Furthermore, when the flow passage of the gate valve is closed, a chamber 46 is formed between the first gate 41 and the second gate 42.

[0053] When the valve stem 43 passes through the valve cover 2, a sealing element 5 is fitted onto the valve stem 43 to improve the sealing performance between the valve stem 43 and the valve cover 2. The sealing element 5 is located on the outside of the valve cover 2. The sealing element 5 is a sealing packing element. Using a sealing packing element for sealing can improve the sealing performance between the valve stem 43 and the valve cover 2.

[0054] The bypass assembly 3 includes a first connecting pipe 31, a second connecting pipe 32, and a third connecting pipe 33. The first connecting pipe 31 and the third connecting pipe 33 are connected, and a first check valve 35 is installed on the connecting pipe, allowing the medium in the first channel 11 to flow unidirectionally into the chamber 46 through the connecting pipe. The second connecting pipe 32 and the third connecting pipe 33 are connected, and a second check valve 36 is installed on the connecting pipe, allowing the medium in the second channel 12 to flow unidirectionally into the chamber 46 through the connecting pipe. Specifically, the valve body 1 has through holes for connecting the first connecting pipe 31, the second connecting pipe 32, and the third connecting pipe 33 respectively. When the first check valve 35 is open, the first channel 11 is connected to the chamber 46 through the first connecting pipe 31 and the third connecting pipe 33; when the second check valve 36 is open, the second channel 12 is connected to the chamber 46 through the second connecting pipe 32 and the third connecting pipe 33.

[0055] In other embodiments, the bypass assembly 3 may also consist only of a pipeline formed by the first connecting pipe 31 and the third connecting pipe 33, with a first check valve 35 provided on the connecting pipe, allowing the medium in the first channel 11 to flow unidirectionally into the chamber 46. Alternatively, the bypass assembly 3 may consist only of a pipeline formed by the second connecting pipe 32 and the third connecting pipe 33, with a second check valve 36 provided on the connecting pipe, allowing the medium in the second channel 12 to flow unidirectionally into the chamber 46.

[0056] It should be noted that in other cases, describing a check valve as a backflow preventer or a one-way valve is within the scope of protection of this application.

[0057] In this embodiment, the gate valve is explained as follows: the medium enters through the first channel 11 and flows out through the second channel 12. In this embodiment, the first gate 41 and the second gate 42 are movably connected, and an elastic element is also provided between the first gate 41 and the second gate 42, forming an elastic double-gate assembly. When the gate valve is shut off and sealed, the elastic force applied to the first gate 41 and the second gate 42 by the elastic element causes the double-gate assembly to come into close contact with the valve seat 13, thereby achieving a seal. Therefore, during the opening and closing process of the gate valve, when the double-gate assembly moves to contact the valve seat 13, the valve seat 13 respectively presses the first gate 41 and the second gate 42. There is a space for movement between the first gate 41 and the second gate 42. At this time, the first gate 41 and the second gate 42 simultaneously press the elastic element, and the elastic element applies an elastic force to the first gate 41 and the second gate 42 respectively. After the double gate assembly contacts the valve seat 13, the friction between them is generated by the elastic force on the gate, resulting in low friction. The opening and closing torque required for the valve stem 43 to move the double gate assembly only needs to overcome this friction. During the movement of the double gate assembly, it is not necessary to overcome the elastic deformation of the sealing surface, thereby reducing the opening and closing torque of the gate valve. Moreover, the reduced friction between the double gate assembly and the valve seat 13 effectively reduces wear on the sealing surface and extends the service life of the gate valve.

[0058] When the double gate assembly closes the gate valve under the action of the valve stem 43, the first gate 41 and the second gate 42 cooperate with the valve seat 13 to seal. The fluid in the first channel 11 enters the chamber 46 through the first connecting pipe 31 and the third connecting pipe 33, thereby forming a fluid pressure balance and creating a fluid pressure self-sealing effect on the double gate assembly, improving the sealing effect. For the first gate 41, the fluid pressure on both sides of the first gate 41 is balanced. Specifically, the side of the first gate 41 closer to the first channel 11 is side A, and the side closer to the chamber 46 is side B. The fluid pressure on side A and side B of the first gate 41 is the same. At this time, the first gate 41 achieves sealing through the elastic force applied to it. The second gate 42 is subjected to fluid pressure, which can form a fluid pressure self-sealing effect. At the same time, the second gate 42 is also subjected to elastic force, giving the second gate 42 a better sealing effect.

[0059] It should be noted that in other embodiments, the medium in the gate valve may also enter through the second channel 12 and flow out through the first channel 11. In this case, when the gate valve is closed, the fluid in the second channel 12 enters the chamber 46 through the second connecting pipe 32 and the third connecting pipe 33. The fluid pressure on both sides of the second gate 42 is balanced, and the second gate 42 achieves sealing through the elastic force applied to it. The first gate 41 is simultaneously sealed by both fluid pressure and elastic force.

[0060] In this embodiment, the valve seat 13 is formed by welding metal onto the valve body 1 or embedding a metal sleeve. Sealing surfaces 423 protrude from the edges of the first gate 41 and the second gate 42, and these sealing surfaces 423 are used for sealing connection with the valve seat 13. The use of an elastic double-gate assembly reduces the requirements for the precision of the sealing surfaces 423 during manufacturing and for the relative dimensions between the two valve seats 13. The double-gate assembly can still maintain its fit with the valve seat 13 through its own elastic force, resulting in strong gate adaptability and interoperability, making the gates more suitable for mass production lines. Furthermore, due to the good adaptability of the double-gate assembly, it is less affected by the elastic deformation of the valve body 1 and valve seat 13 caused by fluid pressure, eliminating the need to thicken the walls of the valve body 1 and valve cover 2, effectively reducing material costs. Moreover, due to the light opening and closing torque, the torque requirement of the actuator 432 is greatly reduced, making it easier to select a smaller, lower-cost actuator 432 and to integrate it into the valve body.

[0061] Combination Figure 3 As shown, the bypass assembly 3 also includes a tee fitting 34. The first connecting pipe 31 is connected to the third connecting pipe 33 through the tee fitting 34, and the second connecting pipe 32 is connected to the third connecting pipe 33 through the tee fitting 34.

[0062] Combination Figure 4 and Figure 5 As shown, the elastic element includes a first elastic element 44 and a second elastic element 45. The first elastic element 44 and the second elastic element 45 are symmetrically arranged on both sides of the axial center line of the valve stem 43, so that the gate plate is subjected to consistent force on both sides of the valve stem 43, avoiding uneven force distribution that would reduce the sealing effect of the gate plate. In other embodiments, other numbers of elastic elements may be provided, and there is no limitation.

[0063] by Figure 2 As illustrated in the mid-view diagram, the first gate 41 and the second gate 42 are inclined, causing the size of the chamber 46 between the first gate 41 and the second gate 42 to gradually decrease in size towards the direction away from the valve stem 43, forming a wedge-shaped structure that is wider at the top and narrower at the bottom. When the gate valve opens, the inclined gates can guide the fluid, reducing the impact of the fluid on the gates. Furthermore, due to the use of an elastic double-gate assembly, the precision of the gate inclination angle is reduced, and the sealing surface of the double-gate assembly can always remain in contact with the valve seat under the action of the elastic element, improving the sealing reliability of the gates.

[0064] Combination Figure 4-9As shown, the first gate 41 and the second gate 42 are movably connected by a hook assembly. The hook assembly includes a first left hook 411 and a second left hook 412 connected to the first gate 41, and a first right hook 421 and a second right hook 422 connected to the second gate 42. The first left hook 411 and the first right hook 421 are engaged, and the second left hook 412 and the second right hook 422 are engaged. A gap exists at the engagement points of the first left hook 411 and the first right hook 421, and at the engagement points of the second left hook 412 and the second right hook 422, to provide space for the first gate 41 and the second gate 42 to move closer to or further away from each other. Specifically, when the first gate 41 and the second gate 42 move between the two valve seats 13, due to the gap, the first gate 41 and the second gate 42 are compressed and can move closer to each other; when the first gate 41 and the second gate 42 leave the valve seat 13, under the action of the elastic element, the first gate 41 and the second gate 42 can move closer to each other. Because the hook assembly is connected in conjunction with the elastic element, the first gate 41 and the second gate 42 will not detach from each other, and the double gate assembly is elastic.

[0065] In a preferred embodiment, two of each of the first left hook 411 and the first right hook 421 are provided, symmetrically located on both sides of the second left hook 412 and the second right hook 422, forming a relatively stable triangle between the connection points of the second left hook 412 and the second right hook 422, and between the connection points of the first left hook 411 and the first right hook 421. Furthermore, the hook opening directions of the first left hook 411 and the second left hook 412 are opposite, as are the hook opening directions of the first right hook 421 and the second right hook 422, preventing the hook assembly from disengaging when the double gate assembly moves along the valve stem 43.

[0066] Combination Figure 4 , Figure 8 and Figure 9 As shown, a valve stem nut 431 is threaded onto the valve stem 43, and the valve stem nut 431 is located between and connected to the second left hook 412 and the second right hook 422. The actuator 432 drives the valve stem 43 to rotate, causing the valve stem nut 431 to move along the valve stem 43, while the valve stem nut 431 drives the double gate assembly to move. By positioning the valve stem nut 431 between the second left hook 412 and the second right hook 422, the valve stem nut 431 is recessed into the space where the double gate assembly is located, which reduces the installation height of the gate valve, thereby reducing the space occupied by the gate valve in terms of height. In addition, due to the reduction of the gate valve's opening and closing twist, a smaller actuator can be selected, thereby further reducing the overall height of the gate valve.

[0067] The valve stem nut 431 is located between the second left hook 412 and the second right hook 422. A slotted hole is formed between the second left hook 412 and the second right hook 422 to provide space for the first gate 41 and the second gate 42 to move closer or further apart. An upper limit block 4311 and a lower limit block 4312 protrude from the valve stem nut 431, located on either side of the second left hook 412 and the second right hook 422, respectively. The upper limit block 4311 and the lower limit block 4312 limit and clamp the second left hook 412 and the second right hook 422, thereby enabling the valve stem nut 431 to move synchronously with the double gate assembly. On one side near the lower limit block 4312, the second left hook 412 and the second right hook 422 are recessed with positioning grooves 424. The lower limit block 4312 is fitted into the positioning grooves 424. Both the lower limit block 4312 and the positioning grooves 424 are polygonal, for example... Figure 8 The quadrilateral shown in the diagram, after the lower limit block 4312 is connected to the positioning groove 424, limits the valve stem nut 431, preventing the valve stem nut 431 from rotating when the valve stem 43 rotates. In other embodiments, the positioning groove 424 can also be formed on the side of the second left hook 412 and the second right hook 422 near the upper limit block 4311, with the upper limit block 4311 connected to the positioning groove 424, and both the upper limit block 4311 and the positioning groove 424 are polygonal.

[0068] The gate valve in this design uses a flexible double gate assembly, which, together with the bypass assembly 3, forms a fluid self-sealing mechanism. This reduces the opening and closing torque of the gate valve, reduces wear on the sealing surface, and improves the sealing performance, thereby extending the service life of the gate valve.

[0069] The terms “installation,” “setup,” “equipped with,” and “connection” used herein should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0070] The present invention and its embodiments have been described above illustratively. This description is not restrictive, and the figures shown are only one embodiment of the present invention; the actual structure is not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the inventive spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. A gate valve, comprising: A valve body (1) has a fluid channel inside, the fluid channel including a first channel (11) and a second channel (12), and valve seats (13) are provided on the valve body sidewalls where the first channel (11) and the second channel (12) are close to each other. It is characterized by further comprising: The dual-gate assembly includes a first gate (41) and a second gate (42) movably connected together, and at least one elastic element is provided between the first gate (41) and the second gate (42) for applying an elastic force to the first gate (41) and the second gate (42); The valve stem (43) has one end located outside the valve body (1) and the other end extending into the valve body (1) to connect with the double gate assembly. It can drive the double gate assembly to reciprocate along the valve stem (43) to control the opening and closing of the fluid channel. When the double gate assembly moves to seal contact with the valve seat (13) to close the fluid channel, a chamber (46) is formed between the first gate (41) and the second gate (42). The bypass assembly (3) includes a third connecting pipe (33), and also includes a first connecting pipe (31) and / or a second connecting pipe (32); A first check valve (35) is provided on the connecting pipe formed by the connection of the third connecting pipe (33) and the first connecting pipe (31), through which the medium in the first channel (11) can flow unidirectionally to the chamber (46); and / or, a second check valve (36) is provided on the connecting pipe formed by the connection of the third connecting pipe (33) and the second connecting pipe (32), through which the medium in the second channel (12) can flow unidirectionally to the chamber (46).

2. The gate valve according to claim 1, characterized in that: The bypass assembly (3) further includes a tee (34); the first connecting pipe (31) is connected to the third connecting pipe (33) through the tee (34), and the second connecting pipe (32) is connected to the third connecting pipe (33) through the tee (34).

3. The gate valve according to claim 1 or 2, characterized in that: The elastic element includes a first elastic element (44) and a second elastic element (45), which are respectively symmetrically arranged on both sides of the axial center line of the valve stem (43).

4. The gate valve according to claim 3, characterized in that: The first gate (41) and the second gate (42) are inclined so that the size of the chamber (46) between the first gate (41) and the second gate (42) gradually decreases in the direction away from the valve stem (43).

5. The gate valve according to claim 1, characterized in that: The first gate (41) and the second gate (42) are movably connected by a hook assembly; The hook assembly includes a first left hook (411) and a second left hook (412) connected to the first gate (41), and a first right hook (421) and a second right hook (422) connected to the second gate (42). The first left hook (411) and the first right hook (421) are connected together, and the second left hook (412) and the second right hook (422) are connected together.

6. The gate valve according to claim 5, characterized in that: Two of each of the first left hook (411) and the first right hook (421) are provided and are symmetrically located on both sides of the second left hook (412) and the second right hook (422).

7. The gate valve according to claim 5, characterized in that: The hook opening directions of the first left hook (411) and the second left hook (412) are opposite, and the hook opening directions of the first right hook (421) and the second right hook (422) are opposite.

8. The gate valve according to claim 7, characterized in that: The valve stem (43) is threaded with a valve stem nut (431), and the valve stem nut (431) is located between the second left hook (412) and the second right hook (422) and is connected to the second left hook (412) and the second right hook (422).

9. The gate valve according to claim 4, characterized in that: A sealing surface (423) is provided at the edge of the first gate (41) and the second gate (42), and the sealing surface (423) is used to seal and connect with the valve seat (13).

10. The gate valve according to claim 1, characterized in that: A valve body opening (14) is opened on one side of the valve body (1), and a valve cover (2) is provided over the valve body opening (14). The valve stem (43) is set through the valve cover (2).

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