Parallel gate valve adopting expansion blocks to open double valve discs

Abstract

The utility model relates to a parallel gate valve adopting expansion blocks to open double valve discs, and belongs to the technical field of valves. Comprising a valve body, a valve rod assembly, valve disc assemblies and an expansion assembly arranged between two valve discs, and the expansion assembly comprises a first expansion block connected with the valve rod assembly so as to axially move along with the valve rod assembly; the second expansion block is in wedge-shaped sliding fit with the first expansion block, the second expansion block extends in the axial direction of the valve body, and an elastic pressure applying arm is formed at the position close to the bottom of the valve body; an abutting piece corresponding to the elastic pressure applying arm in position is formed on a valve seat of the valve body. In the bottom area of the valve disc, the area can obtain additional sealing force through the interaction of the elastic pressure applying arm and the valve seat abutting piece, so that the sealing reliability and durability of the valve on the whole circumference of the valve disc, especially the sealing reliability and durability of the bottom of the valve disc are improved, and leakage is effectively prevented.

Description

Technical Field

[0001] The utility model belongs to the technical field of valves, and in particular relates to a parallel gate valve which adopts an expansion block to prop open a double valve disc. Background Art

[0002] As a key pipeline control component, gate valves are widely used in many industrial fields such as petroleum, chemical industry, electricity, water supply, etc. Their main function is to connect or cut off the flow of media in the pipeline. According to the structural characteristics of their opening and closing parts, gate valves can be divided into wedge-type and parallel-type types. Parallel gate valves usually have two parallel valve disc sealing surfaces, which produce less friction with the valve seat sealing surface during the opening and closing process, have relatively low operating torque, and have a certain degree of self-adaptation to deformation caused by temperature changes. Therefore, they are favored under specific working conditions.

[0003] In actual industrial pipelines, the fluid medium is often not completely pure and may contain solid particles, impurities, scale or sediment. These substances are very likely to accumulate in the bottom cavity of the valve body, the bottom of the valve seat and the bottom edge of the valve disc when the flow rate is low or the valve is not frequently opened and closed. When the valve is closed, these accumulations will hinder the close fit between the bottom of the valve disc and the valve seat, directly forming a leakage channel. This is a very common and important reason for the failure of the valve bottom seal. Utility Model Content

[0004] In order to solve the above-mentioned problems in the prior art, the utility model provides a parallel gate valve which adopts an expansion block to prop open a double valve disc.

[0005] In order to achieve the above purpose, the technical solution adopted by the utility model is:

[0006] Provided is a parallel gate valve using an expansion block to prop open a double valve disc, comprising a valve body, a valve stem assembly and a valve disc assembly, wherein the valve disc assembly comprises two valve discs, and the two valve discs are adapted to move along the axial direction of the valve body under the drive of the valve stem assembly to open and close the gate valve;

[0007] An expansion assembly is arranged between the two valve discs, and the expansion assembly comprises:

[0008] A first expansion block connected to the valve stem assembly to move axially therewith;

[0009] A second expansion block that is wedge-shaped and slidingly matched with the first expansion block and connected to the valve disc;

[0010] Wherein, the second expansion block extends along the axial direction of the valve body and forms an elastic pressure arm at a position close to the bottom of the valve body;

[0011] And, an abutment piece corresponding to the position of the elastic pressure arm is formed on the valve seat of the valve body;

[0012] Moreover, the elastic pressing arm is in a radially expanded deformation state due to the interaction with the abutting member, and this expanded deformation state is used to push the valve disc onto the valve seat of the valve body.

[0013] Preferably, the elastic pressing arm has a deformation rib portion;

[0014] The deformation rib portion is arranged on the end face of the elastic pressing arm facing the valve disc;

[0015] Wherein, the deformation rib portion expands radially synchronously with the elastic pressing arm.

[0016] Preferably, the deformation rib portion is at least one convex rib-like structure extending along the end face of the elastic pressing arm and integrally formed.

[0017] Preferably, at the connection position between the elastic pressing arm and the second expansion block, a smooth and curved transition structure is formed in the direction towards the valve disc.

[0018] Preferably, between the inner sides of the two elastic pressing arms, a wedge-shaped acting channel extending along the axial direction of the valve body is jointly defined;

[0019] Wherein, the wedge-shaped acting channel has a conical region with a decreasing width from one end to the other end until a minimum width region is formed.

[0020] Preferably, it includes:

[0021] A coupling component, which includes:

[0022] A first coupling member, connected to the first expansion block and having a coupling hole;

[0023] A second coupling member, connected to the valve disc and slidably positioned in the coupling hole.

[0024] Preferably, the coupling hole of the first coupling member is an oblong or rectangular guide groove extending along the transverse movement direction of the valve disc;

[0025] Moreover, the second coupling member has a guide protrusion or pin shaft that slidably cooperates with the oblong or rectangular guide groove.

[0026] Preferably, the first expansion block has:

[0027] A connection end, which is configured to be suitable for connecting with the valve stem assembly to receive and transmit the axial driving force from the valve stem assembly;

[0028] A driving body, fixedly connected to the connection end and having at least one first wedge-shaped working surface;

[0029] Wherein, the first wedge-shaped working surface is configured to be slidably matched with the corresponding second wedge-shaped working surface on the second expansion block.

[0030] Preferably, the first expansion block has a first constraint portion;

[0031] The second expansion block has a second restraining portion;

[0032] Wherein, at least within a stroke section of the valve stem assembly to open the gate valve, the first constraint portion and the second constraint portion form abutment.

[0033] Preferably, the second expansion block has:

[0034] A guide slot, wherein the first coupling member is slidably connected to the guide slot;

[0035] Wherein, the length L1 of the guiding through groove is greater than the length L2 of the first coupling member.

[0036] The utility model provides a parallel gate valve using an expansion block to prop open a double valve disc. The beneficial effects of the utility model are as follows:

[0037] In the bottom area of the valve disc, the elastic pressure arm and the valve seat abutment interact with each other to provide an additional sealing force in this area. This not only helps to overcome the problem of insufficient bottom sealing force caused by machining, assembly or solid medium wear in traditional expansion block mechanisms, but also compensates for the slight unevenness of the valve seat or valve disc to a certain extent, thereby significantly improving the sealing reliability and durability of the valve around the entire circumference of the valve disc, especially at the bottom, and effectively preventing leakage. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 A three-dimensional diagram of a parallel gate valve using an expansion block to prop open a double valve disc proposed by the utility model;

[0039] Figure 2 It is a cross-sectional view of a parallel gate valve using an expansion block to prop open a double valve disc proposed by the utility model;

[0040] Figure 3 A schematic diagram of the structural coordination of the first expansion block and the second expansion block in the parallel gate valve using the expansion block to prop open the double valve discs proposed by the utility model;

[0041] Figure 4 for Figure 3 A front view of the structure shown;

[0042] Figure 5 This is a structural schematic diagram of the first expansion block in the parallel gate valve using an expansion block to prop open the double valve discs proposed by the utility model;

[0043] Figure 6This is a schematic diagram of the structure of the second expansion block in the parallel gate valve using the expansion block to prop open the double valve discs proposed by the utility model;

[0044] Figure 7 for Figure 6 Front view of the structure shown.

[0045] Description of reference numerals:

[0046] 1. Valve body; 2. Valve stem assembly; 3. Valve disc; 4. Expansion assembly; 401. First expansion block; 4011. Connection end; 4012. Driving body; 4013. First wedge-shaped working surface; 4014. First constraint portion; 402. Second expansion block; 4021. Second wedge-shaped working surface; 4022. Second constraint portion; 4023. Guide groove; 403. Elastic pressure arm; 4031. Deformation rib; 4032. Transition structure; 404. Abutment; 405. Wedge-shaped action channel; 4051. Conical area; 4052. Minimum width area; 501. First coupling member; 5011. Coupling hole; 502. Second coupling member; 6. Valve seat. DETAILED DESCRIPTION

[0047] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0048] See also Figures 1 - 7 As shown, the specific embodiments provided by the utility model are as follows:

[0049] like Figures 1 to 7 As shown, in order to overcome the problems of existing parallel gate valves, especially the uneven sealing or damage caused by fluid impact that may exist in the bottom area of the valve disc 3, an embodiment of the utility model provides a parallel gate valve that uses an expansion block to prop open the double valve discs 3, aiming to enhance the sealing reliability of the valve through an elastic pressure and abutment mechanism, especially for the lower area of the valve disc 3.

[0050] The parallel gate valve using an expansion block to open a double valve disc 3 comprises a valve body 1, a valve stem assembly 2 and a valve disc 3 assembly. The valve body 1 defines a channel for the flow of the medium, and a valve seat 6 for cooperating with the valve disc 3 to form a seal is arranged at an appropriate position in the channel. The valve stem assembly 2 is the operating mechanism of the valve, which is usually driven by a hand wheel or other driving device to realize the axial reciprocating motion of the valve stem, thereby controlling the opening and closing of the valve.

[0051] The valve disc 3 assembly includes two substantially parallel valve discs 3. These two valve discs 3 are configured to be able to move linearly synchronously along the axial direction of the valve body 1 under the drive of the valve stem assembly 2, so as to open the valve to a predetermined degree or close it completely.

[0052] Between the two valve discs 3, an expansion assembly 4 is provided. The expansion assembly 4 includes a first expansion block 401 and a second expansion block 402.

[0053] Among them, the first expansion block 401 is directly connected to the valve stem assembly 2 and moves axially synchronously with the axial movement of the valve stem assembly 2.

[0054] Among them, the two second expansion blocks 402 are respectively located on both sides of the first expansion block 401 and respectively act on one of the two valve discs 3. Each second expansion block 402 has a wedge-shaped sliding fit with at least one wedge-shaped surface of the first expansion block 401. This means that when the first expansion block 401 has an axial displacement relative to the second expansion block 402, the wedge-shaped surfaces between them will interact to convert the axial force into a force that causes the second expansion block 402 to have a lateral displacement. At the same time, each second expansion block 402 is connected to the corresponding valve disc 3, and this connection method allows the valve disc 3 to move laterally under the drive of the second expansion block 402, and also ensures the followability of the valve disc 3 when the valve stem drives the first expansion block 401 to perform an overall axial movement.

[0055] In a specific embodiment, the first expansion block 401 has a first wedge-shaped working surface 4013, and the second expansion block 402 has a second wedge-shaped working surface 4021 and has a sliding fit with the first wedge-shaped working surface 4013.

[0056] On the above basis, the main body part of the second expansion block 402 extends downward along the axial direction of the valve body 1, and an elastic pressing arm 403 is integrally formed at a position close to the bottom of the valve body 1. Correspondingly, on the valve seat 6 of the valve body 1, one or more abutting members 404 are formed at positions corresponding to each elastic pressing arm 403. The abutting member 404 is a fixed protrusion, step or other preset contact structure on the valve seat 6.

[0057] Specifically, when the valve is closed, the valve stem assembly 2 drives the first expansion block 401 to move downward, and then drives the second expansion block 402 and the valve disc 3 assembly as a whole to move towards the valve seat 6 through a wedge-shaped sliding fit. In this process, first, the main body sealing surface of the valve disc 3 may initially contact the valve seat 6. As the valve stem assembly 2 continues to apply a downward closing force, the elastic pressing arm 403 located at the lower part of the second expansion block 402 will contact the corresponding abutting member 404 on the valve seat 6 and receive a reaction force.

[0058] Due to the structural characteristic that the elastic pressing arm 403 can radially expand and deform towards the corresponding valve disc 3, under the combined action of the continuous reaction force from the abutting member 404, the elastic pressing arm 403 will undergo the expected radial expansion deformation towards its corresponding valve disc 3. The force generated by this expansion deformation will push the corresponding valve disc 3, especially the lower region of the valve disc 3, more forcefully onto the valve seat 6 of the valve body 1, thereby enhancing the sealing effect in this region.

[0059] Therefore, in the bottom region of the valve disc 3, through the interaction between the elastic pressing arm 403 and the abutting member 404 of the valve seat 6, an additional sealing force can be obtained in this region. This not only helps to overcome the problem of insufficient bottom sealing force that may exist in the traditional expansion block mechanism due to processing, assembly, or wear of solid media, but also compensates to a certain extent for the possible slight unevenness of the valve seat 6 or the valve disc 3, thereby significantly improving the sealing reliability and durability of the valve around the entire circumference of the valve disc 3, especially at the bottom, and effectively preventing leakage.

[0060] In one embodiment, the elastic pressing arm 403 has a deformation rib portion 4031. The deformation rib portion 4031 is formed on the end face of the elastic pressing arm 403 facing the valve disc 3.

[0061] In a preferred embodiment, the deformation rib portion 4031 is specifically embodied as at least one raised rib-like structure extending along the end face of the elastic pressing arm 403 and integrally formed with the main body of the elastic pressing arm 403. Of course, the deformation rib portion 4031 can also be other forms of protrusions, such as a dot array, a specific wavy contour, etc.

[0062] Among them, when the elastic pressing arm 403 undergoes overall radial expansion deformation due to the interaction with the abutting member 404 on the valve seat 6, the deformation rib portion 4031 provided on its end face will synchronously undergo radial expansion following the main body of the elastic pressing arm 403. Thereby, a thrust is applied to the valve disc 3 to further improve the sealing ability of the valve disc 3.

[0063] More specifically, in the transition region where each second expansion block 402 is connected to the elastic pressing arm 403, a curved transition structure 4032 is formed that faces the valve disc 3 and has a smooth contour.

[0064] Specifically, this smooth curved transition structure 4032 can be embodied as an arc or a gradually changing curve with a preset large radius of curvature, rather than a sharp right angle or a small-angle turn.

[0065] Based on this, when the elastic pressure arm 403 interacts with the abutment 404 on the valve seat 6 and undergoes radial expansion deformation to push the valve disc 3, its root, that is, the transition area connected to the main body of the second expansion block 402, is one of the main stress-bending areas. The smooth curved transition structure 4032 can effectively disperse the stress concentration here and avoid excessive local stress at the geometric mutation point, thereby improving the bending strength, fatigue resistance and overall service life of the elastic pressure arm 403, ensuring that it is not prone to breakage or early failure during repeated expansion deformation.

[0066] On the other hand, the smooth curved transition structure 4032 can guide the initial bending direction and subsequent deformation mode of the elastic pressure arm 403 when the elastic pressure arm 403 is deformed under force, so that its expansion deformation is more inclined to the desired shape that can effectively push the valve disc 3.

[0067] In a specific embodiment, the elastic pressure arms 403 of two different valve discs 3 define and form a wedge-shaped action channel 405 extending axially along the valve body 1 between their inner side surfaces facing each other.

[0068] More specifically, the wedge-shaped action channel 405 has at least one tapered area 4051 whose width or spacing between inner walls gradually decreases from one end thereof, such as an end closer to the root of the elastic pressure arm 403 connected to the main body of the second expansion block 402, to the other end thereof, such as the free end of the elastic pressure arm 403, until the channel forms a predetermined minimum width area 4052 in this direction.

[0069] The reason is that the wedge-shaped action channel 405 can guide the entire elastic pressure arm 403 to expand and deform when the elastic pressure arm 403 is subjected to force, that is, to deform in the direction toward the valve disc 3, thereby applying a thrust to the valve disc 3 to ensure sealing.

[0070] In a specific implementation, a coupling component is included. The coupling component includes a first coupling member 501 and a second coupling member 502 .

[0071] Specifically, the first coupling member 501 is connected to the first expansion block 401, or can be directly integrally formed as a part of the first expansion block 401. The first coupling member 501 is provided with a coupling hole 5011.

[0072] In a preferred embodiment, in order to give the valve disc 3 the necessary lateral freedom of movement, the coupling hole 5011 is an oblong guide groove or a rectangular guide groove extending along the direction in which the valve disc 3 undergoes lateral sealing movement.

[0073] Specifically, the second coupling member 502 is connected to a side of the valve disc 3 facing away from the sealing surface, or can also be integrally formed as a part of the valve disc 3 .

[0074] In a preferred embodiment, the second coupling member 502 is a guiding bump, a T-shaped head or a cylindrical pin shaft, and the cross-sectional shape and size thereof are adapted to the width of the guiding groove on the first coupling member 501 to ensure smooth sliding between the two and stable guiding.

[0075] When the valve approaches the closed position and the wedge-shaped sliding fit between the first expanding block 401 and the second expanding block 402 starts to act, driving the second expanding block 402 to apply a lateral thrust to the valve disc 3, the second coupling member 502 connected to the valve disc 3 can freely slide in the oval or rectangular guiding groove of the first coupling member 501, thereby ensuring the movement of the valve disc 3 in the lateral position.

[0076] In a specific embodiment, the first expanding block 401 includes a connecting end 4011 and a driving body 4012.

[0077] Wherein, the connecting end 4011 is a mechanical connection between the first expanding block 401 and the valve stem assembly 2. Its specific structure can be diverse. For example, it can be a hole with internal threads for screwing with the threaded end of the valve stem; or it can be a T-shaped groove, a fork-shaped head or other structures that can be reliably connected to the end of the valve stem assembly 2 and effectively transmit axial thrust and tension. This connecting end 4011 ensures that when the valve stem assembly 2 makes an axial reciprocating motion, the first expanding block 401 can be driven synchronously, so as to receive and transmit all axial driving forces from the valve stem assembly 2.

[0078] Wherein, the driving body 4012 is the main body part of the first expanding block 401 and is fixedly connected to the connecting end 4011. Moreover, the driving body 4012 is formed with at least one first wedge-shaped working surface 4013.

[0079] In a double-valve-disc 3 parallel gate valve, if the expansion assembly 4 acts symmetrically on the two valve discs 3, the driving body 4012 of the first expanding block 401 is a double-sided symmetric wedge-shaped structure, that is, it has two first wedge-shaped working surfaces 4013 with opposite directions or symmetrically distributed, and each first wedge-shaped working surface 4013 corresponds to a second expanding block 402 respectively. Correspondingly, the second expanding block 402 is provided with a second wedge-shaped working surface 4021, and it is an inclined surface matching the wedge-shaped surface of the first expanding block 401.

[0080] In a specific embodiment, a first constraint portion 4014 is formed on the first expanding block 401. The first constraint portion 4014 can be a stop surface, a shoulder, a pin or a contact surface with a specific profile.

[0081] Correspondingly, a second constraint portion 4022 is formed on the second expanding block 402. The geometric shape and position of the second constraint portion 4022 match those of the first constraint portion 4014 so that the two can have effective mechanical abutment under specific conditions.

[0082] When the valve is in the fully closed state, the first expansion block 401 and the second expansion block 402 are closely matched through the wedge-shaped working surface, and the second expansion block 402 presses the valve disc 3 against the valve seat 6 to achieve sealing. In this state, there is a gap between the first constraint portion 4014 and the second constraint portion 4022. When the user operates the valve stem assembly 2 to open the gate valve, the valve stem will first drive the first expansion block 401 to move axially upward (or in the direction of valve opening). Within this stroke, the first constraint portion 4014 on the first expansion block 401 will mechanically abut against the corresponding second constraint portion 4022 on the second expansion block 402, so as to drive the second expansion block 402 to move synchronously in the direction of valve opening.

[0083] In a specific implementation, the second expansion block 402 is provided with a guide groove 4023 .

[0084] Specifically, the guide slot 4023 is formed on the body of the second expansion block 402 to allow the first coupling member 501 to pass through the solid portion of the second expansion block 402 .

[0085] The inner wall surface of the guide groove 4023 can provide certain guidance for the movement trajectory of the first coupling member 501 passing through or accommodated therein, ensuring that the first expansion block 401 and the second expansion block 402 can maintain the correct alignment and movement posture when relative displacement occurs.

[0086] The length L1 of the guiding slot 4023 is greater than the length L2 of the first coupling member 501 , so as to provide space for the first coupling member 501 and the first expansion block 401 connected thereto to move relative to the second expansion block 402 .

[0087] Specifically, when the first expansion block 401 moves axially relative to the second expansion block 402 to open the second expansion block 402 through the wedge surface, the gap provided by L1>L2 allows relative axial displacement to occur, so that the wedge surface can fully engage and generate sufficient lateral opening force. When the valve is opened, when the first expansion block 401 retracts to release the wedge effect, this relative displacement space is also required to ensure that the wedge surface can be effectively separated and the second expansion block 402 can retract smoothly.

[0088] In the description of the embodiments of the present invention, it needs to be understood that terms such as “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “center”, “top”, “bottom”, “top”, “bottom”, “inside”, “outside”, “inside”, and “outside” indicate orientation or positional relationships.

[0089] In the description of the embodiments of the present utility model, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", "linkage", and "assembly" shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0090] In the description of the embodiments of the present utility model, specific features, structures, materials, or characteristics may be combined in a suitable manner in any one or more of the embodiments or examples.

[0091] In the description of the embodiments of the present utility model, it should be understood that "-" and "~" represent the range between two numerical values, and this range includes the endpoints. For example: "A - B" represents the range greater than or equal to A and less than or equal to B. "A ~ B" represents the range greater than or equal to A and less than or equal to B.

[0092] In the description of the embodiments of the present utility model, the term "and / or" herein only describes the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " herein generally represents an "or" relationship between the associated objects before and after.

[0093] Although the embodiments of the present utility model have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirits of the present utility model. The scope of the present utility model is defined by the appended claims and their equivalents.

Claims

1. A parallel gate valve using an expansion block to prop open a double valve disc, comprising a valve body, a valve stem assembly and a valve disc assembly, characterized in that: The valve disc assembly includes two valve discs, which are suitable for moving along the axial direction of the valve body under the drive of the valve stem assembly to open and close the gate valve; An expansion assembly is arranged between the two valve discs, and the expansion assembly comprises: A first expansion block connected to the valve stem assembly to move axially therewith; A second expansion block that is wedge-shaped and slidingly matched with the first expansion block and connected to the valve disc; Wherein, the second expansion block extends along the axial direction of the valve body and forms an elastic pressure arm at a position close to the bottom of the valve body; And, an abutment piece corresponding to the position of the elastic pressure arm is formed on the valve seat of the valve body; Furthermore, the elastic pressure arm is in a radial expansion deformation state due to the interaction with the abutment member, and the expansion deformation state is used to push the valve disc to the valve seat of the valve body.

2. The parallel gate valve using expansion blocks to expand two valve discs according to claim 1, characterized in that, The elastic pressure arm has a deformation rib; The deformation rib is arranged on the end surface of the elastic pressure arm facing the valve disc; Wherein, the deformation rib portion expands radially synchronously with the elastic pressure arm.

3. The parallel gate valve using an expansion block to expand two valve discs according to claim 2, wherein The deformation rib is at least one protruding ridge-shaped structure extending along the end surface of the elastic pressure arm and formed integrally.

4. The parallel gate valve using expansion blocks to prop open double valve discs according to claim 3 is characterized in that: A connecting position between the elastic pressure arm and the second expansion block forms a smoothly curved transition structure toward the valve disc.

5. The parallel gate valve using expansion blocks to prop open double valve discs according to claim 4 is characterized in that: The two elastic pressure arms jointly define a wedge-shaped action channel extending axially along the valve body between their inner sides; The wedge-shaped action channel has a tapered area whose width decreases from one end to the other end until a minimum width area is formed.

6. The parallel gate valve using an expansion block to expand two valve discs according to claim 1 or 2, characterized in that, include: A coupling component, the coupling component comprising: A first coupling member, connected to the first expansion block and having a coupling hole; The second coupling member is connected to the valve disc and is slidably positioned in the coupling hole.

7. The parallel gate valve using expansion blocks to prop open double valve discs according to claim 6, characterized in that: The coupling hole of the first coupling member is an oblong or rectangular guide groove extending along the lateral moving direction of the valve disc; Furthermore, the second coupling member has a guide protrusion or a pin which is slidably matched with the oblong or rectangular guide groove.

8. The parallel gate valve using an expansion block to expand two valve disks according to claim 1 or 2, characterized in that, The first expansion block has: A connecting end, the connecting end being configured to be connected to the valve stem assembly to receive and transmit an axial driving force from the valve stem assembly; A driving body, which is fixedly connected to the connecting end and has at least one first wedge-shaped working surface; Wherein, the first wedge-shaped working surface is configured to be slidably matched with the corresponding second wedge-shaped working surface on the second expansion block.

9. The parallel gate valve using expansion blocks to prop open double valve discs according to claim 8, characterized in that: The first expansion block has a first restraining portion; The second expansion block has a second restraining portion; Wherein, at least within a stroke section where the valve stem assembly opens the gate valve, the first constraint portion and the second constraint portion form an abutment.

10. The parallel gate valve using expansion blocks to open double valve discs according to claim 6, characterized in that: The second expansion block has: a guiding through groove, and the first coupling member is slidably connected to the guiding through groove; wherein, the length L1 of the guiding through groove is greater than the length L2 of the first coupling member.

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