A low-torque gate valve and an assembly method

Abstract

The present invention discloses a low-torque gate valve and an assembly method, belonging to the technical field of valves. It includes a valve body, a valve cover, a valve stem assembly and a valve flap assembly. A valve cavity is provided inside the valve body, and a feed port and a discharge port are provided on both sides of the valve cavity; the valve cover has openings at both the upper and lower ends and is covered on the valve body; the valve stem assembly includes a valve stem, the upper end of the valve stem penetrates through the valve cover, and the lower end is disposed in the valve cavity. A plug thrust bearing that is clamped with the upper opening of the valve cover is sleeved on the upper end of the valve stem. A limiting boss is provided on the valve stem, and the limiting boss is located below the plug thrust bearing and is used for axial limiting of the valve stem; the valve flap assembly includes a valve flap body, and a valve flap nut that is clamped inside the valve flap body and is threadedly connected to the lower end of the valve stem. The low-torque gate valve of the present invention has a simple structure, simplifies the processing technology of parts, saves production costs, and is easy to assemble and debug.

Description

Technical Field

[0001] The present invention belongs to the technical field of valves, and more specifically, relates to a low-torque gate valve and an assembly method thereof. Background Art

[0002] In the prior art, a gate valve is installed on a liquid delivery pipeline system. The gate valve drives the valve flap assembly to move through the rotation of the valve stem to realize the opening and closing of the gate valve. During the assembly process of the gate valve, it is found that the valve stem needs to maintain good concentricity with the valve cover and the valve body, and the assembly precision requirement is high. Otherwise, the valve stem will get stuck during the process of driving the valve flap assembly to open and close the gate valve, which requires high machining precision of the parts in the gate valve and results in high production costs. In addition, the plug thrust is generally fixed to the valve cover by threads, and both the plug thrust and the valve cover need to be thread-machined. There are many parts machining processes. When installing and debugging the concentricity between the valve stem and the valve cover, the plug thrust needs to be disassembled and assembled, which is inconvenient for debugging. Moreover, in the prior art, the plug thrust is mostly made of cast iron and is provided with a plastic lining for assembly with the valve stem. The valve stem is generally made of stainless steel. There are many parts and the assembly process is relatively complex. At the same time, during the long-term use process, the plastic lining is easily worn, resulting in an increase in torque and a reduction in service life. Also, the rubber coating thickness of the valve flap assembly is uneven, resulting in poor sealing performance when the gate valve is closed. Summary of the Invention

[0003] Aiming at the defects of the prior art, the purpose of the present invention is to provide a low-torque gate valve and an assembly method thereof, aiming to solve the problems of high assembly precision requirement, high production cost, inconvenient debugging, low service life, and poor sealing performance when the gate valve is closed in the prior art.

[0004] To achieve the above purpose, the present invention provides a low-torque gate valve, which includes a valve body, a valve cover, a valve stem assembly, and a valve flap assembly, wherein:

[0005] A valve cavity is provided inside the valve body, and a feed port and a discharge port are provided on both sides of the valve cavity;

[0006] The valve cover has openings at both upper and lower ends and is covered on the valve body;

[0007] The valve stem assembly includes a valve stem. The upper end of the valve stem penetrates through the valve cover, and the lower end is disposed in the valve cavity. A plug thrust that is clamped with the upper-end opening of the valve cover is sleeved on the valve stem. A limiting boss is provided on the valve stem. The limiting boss is located below the plug thrust and is used for axial limiting of the valve stem;

[0008] The valve flap assembly includes a valve flap body. A valve flap nut that is thread-connected to the lower end of the valve stem is clamped inside the valve flap body. The valve stem can drive the valve flap body to axially move to connect or disconnect the feed port and the discharge port.

[0009] Furthermore, a clamping groove is provided at the upper end of the valve cover, a limiting groove is formed on the side wall of the clamping groove, a clamping block is provided on the outer wall of the plug thrust. During installation, the plug thrust is placed into the clamping groove and rotated by a certain angle, so that the clamping block and the inner wall of the clamping groove are cooperatively clamped to form an inverted buckle structure. The plug thrust is also provided with limiting members having the same number and corresponding positions as the limiting grooves.

[0010] Furthermore, an installation portion is provided at the upper end of the valve flap body. An installation groove is axially formed in the middle of the installation portion. A clamping portion is formed by the side wall of the installation groove extending radially inwards. A first positioning groove is formed in the clamping portion. The valve flap nut is located in the installation groove. A clamping boss corresponding to the position and having the same number as the clamping portion is formed by the side wall of the valve flap nut extending radially outwards. A second positioning groove corresponding to the position of the first positioning groove is formed in the clamping boss. During installation, the valve flap nut is placed in the installation groove and rotated by a certain angle, so that the clamping portion and the clamping boss are rotationally clamped to form an inverted buckle structure, and the first positioning groove and the second positioning groove cooperate to form a positioning hole. A positioning member is provided in the positioning hole. After the valve flap body and the valve flap nut are connected by the positioning member, a rubber coating layer is integrally formed by encapsulating with rubber.

[0011] Furthermore, the limiting member is a positioning pin or a screw, and an anti-rotation cover plate is further provided at the upper end of the valve cover.

[0012] Furthermore, guide columns for limiting the movement of the valve flap body are provided on both sides of the valve cavity.

[0013] Furthermore, both the plug thrust and the valve flap nut are formed by hot stamping of copper materials. Annular grooves are evenly distributed on the inner wall of the plug thrust, and sealing rings for sealing with the outer wall of the valve stem are provided in the annular grooves.

[0014] Furthermore, an arc groove and a stepped hole are coaxially arranged in sequence below the clamping groove. A sealing ring for abutting and sealing with the outer wall of the plug thrust is provided in the arc groove. A gasket is arranged in the stepped hole. The gasket is sleeved on the valve stem and abuts against the bottom surface of the limiting boss.

[0015] Furthermore, a sealing groove is formed on the lower end surface of the valve cover. A sealing member is provided in the sealing groove. The valve cover and the valve body are sealed by the sealing member.

[0016] Furthermore, an installation gap is provided between the limiting groove and the limiting member.

[0017] The present invention also provides an assembly method for a low-torque gate valve, and the method includes the following steps:

[0018] S1. Assembling the valve stem assembly and the valve disc assembly respectively;

[0019] S2, assembling the valve stem assembly and the valve cover;

[0020] S3, connecting the valve flap assembly and the valve stem assembly;

[0021] S4, placing the valve flap assembly in the valve cavity, and covering the valve cover on the valve body and connecting them with screws.

[0022] In general, the above technical solution conceived by the present invention has the following beneficial effects compared with the prior art:

[0023] (1) The valve cover and the plug thrust are connected. When the valve stem rotates, the plug thrust can be driven to rotate a certain angle, so that the valve stem and the plug thrust are automatically aligned, avoiding the valve stem driving the valve disc assembly to open and close the gate valve. The machining accuracy requirements for the parts are not high, and a certain deviation can be allowed when the valve cover and the valve body are assembled, which reduces the production cost and assembly difficulty, is convenient for debugging, and is easy to assemble.

[0024] (2) The plug thrust and valve disc nut are made of copper material by hot stamping, and there is no need to further process the valve cover and plug thrust, which simplifies the processing process, improves assembly efficiency and reduces production costs;

[0025] (3) The plug thrust is made of hot stamped copper material and is directly assembled with the valve stem. It is not easy to wear and does not require a plastic lining. This reduces parts, reduces manufacturing costs, and increases service life.

[0026] (4) After the valve disc body and the valve disc nut are connected by the positioning piece, they are covered with rubber as a whole and provided with a rubber coating layer. The rubber coating is evenly covered, thereby improving the sealing performance when the gate valve is closed.

[0027] (5) The valve cover and the plug thrust are connected by a limit piece after being clamped together, and the valve disc nut and the valve disc body are connected by a positioning piece after being clamped together, both of which form an inverted structure, which is stable and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is an exploded view of the parts of the low torque gate valve provided by the present invention;

[0029] Figure 2 It is a structural schematic diagram of the low torque gate valve provided by the present invention;

[0030] Figure 3 is a cross-sectional view of a low torque gate valve provided by the present invention;

[0031] Figure 4 is a cross-sectional view of the low torque gate valve provided by the present invention from another perspective;

[0032] Figure 5 is Figure 3 The partial enlarged view at position A in

[0033] Figure 6 is the cross-sectional view of the valve disc assembly of the low-torque gate valve provided by the present invention;

[0034] Figure 7 is the structural schematic diagram of the valve disc body of the low-torque gate valve provided by the present invention;

[0035] Figure 8 is the structural schematic diagram of the valve disc nut of the low-torque gate valve provided by the present invention;

[0036] Figure 9 is the structural schematic diagram of the valve cover of the low-torque gate valve provided by the present invention;

[0037] Figure 10 is the assembly schematic diagram of the valve cover and the rotating thrust of the low-torque gate valve provided by the present invention;

[0038] Figure 11 is the structural schematic diagram of the valve body of the low-torque gate valve provided by the present invention;

[0039] The structures corresponding to the respective numerical markings in the drawings are: 1 - valve body, 11 - valve cavity, 111 - guide post, 12 - feed port, 13 - discharge port, 2 - valve cover, 21 - clamping groove, 22 - arc groove, 23 - stepped hole, 24 - gasket, 25 - sealing groove, 26 - seal, 3 - valve stem assembly, 31 - valve stem, 311 - limit boss, 32 - plug thrust, 321 - clamping block, 33 - limit member, 4 - valve disc assembly, 41 - valve disc body, 411 - mounting portion, 412 - mounting groove, 413 - clamping portion, 414 - first positioning groove, 42 - valve disc nut, 421 - clamping boss, 422 - second positioning groove, 43 - positioning member, 44 - rubber coating, 5 - anti-rotation cover plate. Detailed implementation manners

[0040] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0041] Refer to Figures 1 to 11 , the present invention provides a low-torque gate valve, which includes a valve body 1, a valve cover 2, a valve stem assembly 3 and a valve disc assembly 4, wherein:

[0042] The valve body 1 is hollow inside and is provided with a valve cavity 11. Feed ports 12 and a discharge port 13 are provided on both sides of the valve cavity 11. The valve cavity 11 is communicated with the feed ports 12 and the discharge port 13. The valve cover 2 has openings at both the upper and lower ends and is covered on the valve body 1. The valve stem assembly 3 includes a valve stem 31. The upper end of the valve stem 31 penetrates through the valve cover, and the lower end is disposed in the valve cavity 11. A plug thrust 32 that is clamped to the upper opening of the valve cover 2 is sleeved on the upper end of the valve stem 31. In order to axially limit the valve stem 31, a limiting boss 311 is provided on the valve stem 31, and the limiting boss 311 is located below the plug thrust 32.

[0043] The valve flap assembly 4 includes a valve flap body 41. A valve flap nut 42 that is threadedly connected to the lower end of the valve stem 31 is clamped inside the valve flap body 41. When the valve stem 31 rotates, it can drive the valve flap nut 42 to axially move, and then drive the valve flap body 41 to axially move to connect or cut off the feed port 12 and the discharge port 13. The following will combine specific embodiments to detail each component.

[0044] Embodiment 1

[0045] Refer to Figures 1 to 5 and Figure 9 and Figure 10 In the prior art, the valve cover 2 and the plug thrust 32 are threadedly connected, and threading processing needs to be performed on the valve cover 2 and the plug thrust 32. It is found in use that when the valve stem rotates, it will drive the plug thrust 32 to rotate and retreat, and the structure is not stable enough. To simplify the processing procedure and at the same time make the connection between the valve cover 2 and the plug thrust 32 stable, the valve cover 2 and the plug thrust 32 are clamped.

[0046] Specifically, in this embodiment, a clamping groove 21 is provided at the upper end of the valve cover 2. A vertical limiting groove 211 is opened on the side wall of the clamping groove 21. A clamping block 321 is provided on the outer wall of the plug thrust 32, and the number of the clamping blocks 321 is greater than or equal to 2. In this embodiment, preferably, the number of the clamping blocks 321 is 2. During installation, the plug thrust 32 is placed in the clamping groove 21 and rotated by a certain angle. The rotation angle can be designed according to actual needs, as long as the clamping block 321 and the inner wall of the clamping groove 21 cooperate to form a reverse buckle structure to axially limit the plug thrust 32. In this embodiment, the rotation angle is 90°. To prevent the plug thrust 32 from being screwed out of the clamping groove 21, a limiting member 33 with the same number and corresponding position as the limiting groove 211 is further provided on the plug thrust 32, such as Figure 9As shown, further, there is an installation gap between the limiting member 33 and the limiting groove 211, so that the plug thrust 32 can rotate within a certain angle. The rotation angle can be designed according to actual needs. In this embodiment, the range of the rotatable angle is -2° to 2°, that is, 2° to the left and 2° to the right. When there is some misalignment between the valve stem 31 and the valve cover 2, rotating the valve stem 31 can drive the plug thrust 32 to rotate a certain angle in the clamping groove 21 to automatically align, allowing a certain deviation during the assembly of the valve cover and the valve body.

[0047] In this embodiment, to facilitate the connection between the plug thrust 32 and the limiting member 33, a connection hole is provided in the clamping block 321, as Figure 10 shown. In some embodiments, the connection hole is processed with threads, and the limiting member 33 can be directly selected as a screw. Further, to simplify the processing, the connection hole can also be set as a pin hole, that is, the limiting member 33 can be selected as a positioning pin; furthermore, since the plug thrust 32 is integrally formed by hot stamping of copper material, the connection hole can also be stamped into a polygonal hole, and the positioning member 33 is designed accordingly according to the shape of the connection hole.

[0048] To achieve dust-proof sealing of the upper end of the valve cover 2, an anti-rotation cover plate 5 is further provided at the upper end of the valve cover 2. The anti-rotation cover plate 5 is a plastic part, and it is connected to the valve cover 2 by a buckle.

[0049] Embodiment 2

[0050] Refer to Figures 1 to 8 This embodiment is a further improvement based on Embodiment 1, and the details are as follows:

[0051] In the prior art, a threaded connection is mostly adopted between the valve flap body 41 and the valve flap nut 42, and both the valve flap body 41 and the valve flap nut 42 need to be thread - processed. To simplify the process, in this embodiment, the valve flap body 41 and the valve flap nut 42 are connected by snap - fit; specifically, an installation portion 411 is provided at the upper end of the valve flap body 41. An installation groove 412 is axially opened in the middle of the installation portion 411. A snap - fit portion 413 extends radially inwards along the side wall of the installation groove 412. A first positioning groove 414 is opened on the snap - fit portion 413. The valve flap nut 42 is located within the installation groove 412. A snap - fit boss 421 corresponding to the position of the snap - fit portion 413 and having the same number extends radially outwards along the side wall of the valve flap nut 42. A second positioning groove 422 corresponding to the position of the first positioning groove 414 is opened on the snap - fit boss 421; during installation, the valve flap nut 42 is placed within the installation groove 412 and rotated by a certain angle. The rotation angle can be designed according to actual needs and is not limited in this invention. The snap - fit portion 413 and the snap - fit boss 421 are rotationally snap - fitted to form an inverted - buckle structure, and the first positioning groove 414 and the second positioning groove 412 cooperate to form a positioning hole. Preferably, in this embodiment, the rotation angle is 90°; a positioning member 43 is provided within the positioning hole. After the valve flap body 41 and the valve flap nut 42 are connected by the positioning member 43, a rubber coating layer 44 is integrally formed by encapsulating with rubber; to make the rubber coating layer evenly encapsulated and to avoid the rubber coating layer 44 from contacting and colliding with the inner wall of the valve cover 2 when the gate valve is opened and thus cracking, in this example, the upper end surface of the valve flap nut 42 is higher than the upper end surface of the installation portion 411. During the encapsulation process, the outer circle of the non - encapsulated part of the valve flap nut 42 is radially positioned, and the upper end surface of the valve flap nut 42 is axially positioned, so that the thickness of the encapsulation layer is uniform and the gate valve has good sealing performance when closed.

[0052] Furthermore, the valve flap body 42 and the valve flap nut 42 are connected by a positioning member 43. The positioning member 43 can adopt a positioning pin, and its specific shape can be designed accordingly according to the shape of the positioning hole;

[0053] To guide the axial movement of the valve flap assembly, guide columns 111 for limiting the movement of the valve flap body 41 are provided on both sides of the valve cavity 11. The plug thrust 32 and the valve flap nut 42 are both made by hot stamping of copper material. To improve the sealing performance between the valve stem 31 and the plug thrust, annular grooves 322 are evenly distributed on the inner wall of the plug thrust 32, and sealing rings for sealing with the outer wall of the valve stem 31 are provided within the annular grooves 322.

[0054] In order to improve the sealing effect between the valve cover 2 and the valve stem assembly 3, an arc groove 22 and a stepped hole 23 are coaxially arranged in sequence below the clamping groove 21. A sealing ring for abutting and sealing against the outer wall of the plug thrust 32 is arranged in the arc groove 22; Since the valve stem 31 is made of stainless steel and the valve cover 2 is mostly formed by casting with cast iron, and the friction between stainless steel and cast iron is relatively large, therefore, in order to avoid direct contact between the valve stem 31 and the valve cover 2, a gasket 24 is arranged in the stepped hole 23, and the gasket 24 is sleeved on the valve stem 31 and abuts against the bottom surface of the limiting boss 311.

[0055] In order to improve the sealing effect between the valve cover 2 and the valve body 1, a sealing groove 25 is opened on the lower end surface of the valve cover 2, a sealing member 26 is arranged in the sealing groove 25, and the valve cover 2 and the valve body 1 are sealed through the sealing member 26.

[0056] The present invention also provides an assembly method for a low-torque gate valve, and this method includes the following steps:

[0057] S1. Assemble the valve stem assembly 3 and the valve flap assembly 4 respectively;

[0058] S2. Assemble the valve stem assembly 3 and the valve cover 2;

[0059] S3. Connect the valve flap assembly 4 and the valve stem assembly 3;

[0060] S4. Place the valve flap assembly 4 in the valve cavity 11, and fix the valve body 1 and the valve cover 2 with screws.

[0061] Among them, step S1 specifically includes:

[0062] S11. After installing the sealing ring in the annular groove of the plug thrust 32, the plug thrust 32 is sleeved on the valve stem 31 and abuts against the limiting boss 311;

[0063] S12. After the valve flap main body 41 and the valve flap nut 42 are connected through the positioning member 43, the whole is coated with a rubber coating layer 44;

[0064] Among them, step S2 specifically includes:

[0065] S21. Place the gasket 24 in the stepped hole 23 in the valve cover 2, and place the sealing ring in the arc groove 22;

[0066] S22. Pass the valve stem 31 through the valve cover 2, the plug thrust 32 is located in the clamping groove 21 and rotated by a certain angle, and install the limiting member 33;

[0067] S23. Sleeve the anti-rotation cover plate 5 on the valve stem 31, and snap-fix the anti-rotation cover plate 5 and the valve cover 2.

[0068] Among them, step S3 is specifically as follows: Connect the valve flap nut 42 and the valve stem 31, and rotate the valve flap assembly 4 to rise a certain height to ensure that when the valve cover 2 is set on the valve body 1, the entire valve flap assembly 4 is located within the valve cavity 11;

[0069] Among them, step S4 is specifically as follows: Place the seal 26 in the seal groove 25, place the valve flap assembly 4 in the valve cavity 11, and fix the valve body 1 and the valve cover 2 with screws.

[0070] Those skilled in the art can easily understand that the above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A low-torque gate valve, characterized in that: it includes a valve body (1), a valve cover (2), a valve stem assembly (3) and a valve flap assembly (4), wherein: a valve cavity (11) is provided inside the valve body (1), and a feed port (12) and a discharge port (13) are provided on both sides of the valve cavity (11); the upper and lower ends of the valve cover (2) are open and the valve cover (2) is covered on the valve body (1); the valve stem assembly (3) includes a valve stem (31), the upper end of the valve stem (31) penetrates through the valve cover, and the lower end is disposed in the valve cavity (11). A plug thrust (32) that is clamped with the upper opening of the valve cover (2) is sleeved on the upper end of the valve stem (31). A limit boss (311) is provided on the valve stem (31), and the limit boss (311) is located below the plug thrust (32) and is used for axial limit of the valve stem (31); the valve flap assembly (4) includes a valve flap body (41), and a valve flap nut (42) that is threadedly connected to the lower end of the valve stem (31) is clamped inside the valve flap body (41). The valve stem (31) can drive the valve flap body (41) to move axially to connect or disconnect the feed port (12) and the discharge port (13), a clamping groove (21) is provided at the upper end of the valve cover (2), a limit groove (211) is opened on the side wall of the clamping groove (21), and a clamping block (321) is provided on the outer wall of the plug thrust (32). During installation, the plug thrust (32) is placed in the clamping groove (21) and rotated by a certain angle, so that the clamping block (321) and the inner wall of the clamping groove (21) are cooperatively clamped to form an inverted buckle structure. The plug thrust (32) is also provided with limit members (33) having the same number and corresponding positions as the limit grooves (211).

2. The low-torque gate valve according to claim 1, characterized in that: an installation portion (411) is provided at the upper end of the valve flap body (41), an installation groove (412) is axially opened in the middle of the installation portion (411), a clamping portion (413) extends radially inward along the side wall of the installation groove (412), a first positioning groove (414) is opened on the clamping portion (413), the valve flap nut (42) is located in the installation groove (412), and a clamping boss (421) that is corresponding in position and the same in number as the clamping portion (413) extends radially outward along the side wall of the valve flap nut (42). A second positioning groove (422) that is corresponding in position to the first positioning groove (414) is opened on the clamping boss (421); during installation, the valve flap nut (42) is placed in the installation groove (412) and rotated by a certain angle, so that the clamping portion (413) and the clamping boss (421) are rotationally clamped to form an inverted buckle structure, and the first positioning groove (414) and the second positioning groove (422) cooperate to form a positioning hole. A positioning member (43) is provided in the positioning hole, and after the valve flap body (41) and the valve flap nut (42) are connected by the positioning member (43), the whole is integrally rubber-coated with a rubber coating layer (44).

3. The low-torque gate valve according to claim 1, characterized in that: the limiting member (33) is a positioning pin or a screw, and an anti-rotation cover plate (5) is further provided at the upper end of the valve cover (2).

4. The low-torque gate valve according to claim 2, characterized in that: guide posts (111) for limiting the movement of the valve flap body (41) are provided on both sides of the valve cavity (11).

5. The low-torque gate valve according to claim 1, characterized in that: both the plug thrust (32) and the valve flap nut (42) are formed by hot stamping of copper material. The inner wall of the plug thrust (32) is uniformly provided with annular grooves (322), and sealing rings for sealing with the outer wall of the valve stem (31) are provided in the annular grooves (322).

6. The low-torque gate valve according to claim 1, characterized in that: a circular arc groove (22) and a stepped hole (23) are coaxially arranged in sequence below the clamping groove (21). A sealing ring for abutting and sealing with the outer wall of the plug thrust (32) is provided in the circular arc groove (22); a gasket (24) is arranged in the stepped hole (23), and the gasket (24) is sleeved on the valve stem (31) and abuts against the bottom surface of the limiting boss (311).

7. The low-torque gate valve according to claim 1, characterized in that: a sealing groove (25) is formed on the lower end surface of the valve cover (2), a sealing member (26) is provided in the sealing groove (25), and the valve cover (2) and the valve body (1) are sealed by the sealing member (26).

8. The low-torque gate valve according to claim 1, characterized in that: an installation gap is provided between the limiting groove (211) and the limiting member (33).

9. An assembly method of a low-torque gate valve for assembling the low-torque gate valve according to any one of claims 1-8, characterized in that, the method comprises the following steps: S1. Assemble the valve stem assembly (3) and the valve flap assembly (4) respectively; S2. Assemble the valve stem assembly (3) and the valve cover (2); S3. Connect the valve flap assembly (4) and the valve stem assembly (3); S4. Place the valve flap assembly (4) in the valve cavity (11), and cover the valve cover (2) on the valve body (1) and connect them by screws.

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