Valve cover welding type gate valve

Abstract

The utility model discloses a valve cover welding type gate valve which comprises a valve body, a valve cover, a valve rod, a hand wheel, a gate plate and the like, and is mainly characterized in that a positioning cylinder is arranged at the bottom of the valve cover, a circle of upper step surface extending outwards in the radial direction is arranged on the outer circumferential surface of the positioning cylinder, and a circle of lower step surface extending inwards in the radial direction is arranged at the top of a mounting hole. The valve cover can be positioned and inserted in the mounting hole in the top of the valve body in a matched mode only through the positioning cylinder, so that the valve cover and the valve body are not eccentrically assembled, the upper step face can be tightly attached to the lower step face to form an axial limiting contact face, and then the peripheral area of the outer circumference of the axial limiting contact face is fixed through an annular welding seam. Therefore, the improved structure not only simplifies metalworking production, but also eliminates the trouble of regularly fastening the valve cover, omits the application of sealing parts such as a mouth surface gasket and the like, reduces the production cost of the product, can prevent the valve cover from being disassembled at will, reduces the risk of manual misoperation, and improves the sealing performance.

Description

Technical Field

[0001] This utility model relates to a gate valve, specifically a gate valve with a valve cover welded to a mounting hole on the top of the valve body by welding. Background Technology

[0002] Currently, the structure of a gate valve mainly consists of a valve body, a gate installed inside the valve body, a valve cover installed in a mounting hole on the top of the valve body, a valve stem installed in the valve cover, and a handwheel located on the top of the valve cover. The handwheel drives the gate to open and close the valve via the valve stem. The valve cover is typically installed on top of the valve body using a threaded connection and a face gasket for sealing. During metalworking, this requires machining internal and external threads at the joint between the valve body and the valve cover, increasing the number of machining steps and the cost of tools such as taps and dies. Combined with the use of face gaskets and other sealing components, these structural design features increase the production cost. Furthermore, while the valve cover is generally not disassembled after the gate valve is assembled, the threaded installation makes it easy to remove, increasing the risk of human error and significantly affecting the sealing performance at the joint. Additionally, the preload of the threaded valve cover often decreases after a period of use, requiring periodic tightening, which also causes inconvenience. Utility Model Content

[0003] The technical problem to be solved by this utility model is to overcome the defects of the prior art and provide a valve cover welded gate valve that can reduce the production cost of the product, eliminate the trouble of regularly tightening the valve cover, prevent the valve cover from being disassembled at will, and effectively ensure the sealing performance of the valve cover and valve body joint.

[0004] The technical problem of this utility model is solved by the following technical solution:

[0005] A welded gate valve with a valve cover includes a valve body, a gate plate installed inside the valve body, a valve cover installed in a mounting hole at the top of the valve body, a valve stem installed inside the valve cover, and a handwheel located at the top of the valve cover. The handwheel drives the gate plate to open and close the valve via the valve stem. The bottom of the valve cover is provided with a positioning cylinder. The outer circumference of the positioning cylinder is provided with an upper stepped surface extending radially outward. The top of the mounting hole is provided with a lower stepped surface extending radially inward. The valve cover is positioned and inserted into the mounting hole at the top of the valve body via the positioning cylinder, and the upper stepped surface is in close contact with the lower stepped surface to form an axial limiting contact surface. The outer circumferential edge area of ​​the axial limiting contact surface is fixed by an annular weld.

[0006] The outer circumferential edge of the upper step surface is provided with an upper weld position chamfer, and the outer circumferential edge of the lower step surface is provided with a lower weld position chamfer. The upper and lower weld position chamfers are joined together after the axial limiting contact surfaces are in close contact to form an annular welding groove with a V-shaped cross-section. The upper step surface and the lower step surface are coaxial annular planes.

[0007] The annular welding groove is filled with welding to form an annular weld.

[0008] The axial limiting contact surface is perpendicular to the centerline of the valve stem.

[0009] Compared with existing technologies, this utility model mainly features a positioning cylinder at the bottom of the valve cover. The outer circumference of this positioning cylinder has an upper stepped surface extending radially outward, and the top of the mounting hole has a lower stepped surface extending radially inward. The valve cover can be positioned and inserted into the mounting hole at the top of the valve body simply by using the positioning cylinder. This ensures that the assembly between the valve cover and the valve body is not misaligned, and that the upper stepped surface is tightly against the lower stepped surface to form an axial limiting contact surface. A circumferential weld is then used to fix the outer circumferential edge of this axial limiting contact surface, ensuring the connection between the valve cover and the valve body. Obviously, since this structure eliminates the threaded connection at the valve cover and valve body joint, it simplifies the thread processing steps in the metalworking process and reduces the cost of using tools such as taps and dies. It also eliminates the hassle of periodically tightening the valve cover. In particular, it eliminates the need for sealing components such as face gaskets, greatly reducing the production cost. At the same time, the valve cover fixed with a circumferential weld, while ensuring sealing performance, prevents the valve cover from being arbitrarily disassembled, reducing the risk of human error and creating another form of sealing effect. Attached Figure Description

[0010] Figure 1 This is a cross-sectional structural diagram of the present invention.

[0011] Figure 2 This is an enlarged cross-sectional view of the valve cover mounted on top of the valve body.

[0012] Figure 3 for Figure 2 A cross-sectional view of the annular welding groove in which no annular weld has been formed.

[0013] Figure 4 This is a cross-sectional view of the top of the valve body.

[0014] Figure 5 This is a cross-sectional view of the valve cover. Detailed Implementation

[0015] The embodiments of this utility model will now be described in detail with reference to the accompanying drawings.

[0016] like Figures 1-5As shown, 1. Valve body, 11. Mounting hole, 12. Lower step surface, 13. Lower weld position outer chamfer, 2. Valve cover, 21. Valve cover hole, 22. Positioning cylinder, 23. Upper step surface, 24. Upper weld position outer chamfer, 3. Valve stem, 4. Handwheel, 5. Gate, 6. Tightening ring, 7. Circular weld, 8. Circular weld groove.

[0017] A type of gate valve with welded bonnet, such as Figure 1 As shown, this mainly relates to the field of fluid control technology, specifically to a special connection method between the valve cover 2 and the valve body 1 in a civil gate valve.

[0018] The gate valve includes a valve body 1, a gate plate 5 installed inside the valve body, a valve cover 2 installed in the mounting hole 11 on the top of the valve body, a valve stem 3 installed inside the valve cover, and a handwheel 4 set on the top of the valve cover. The upper end of the valve stem extends out of the valve cover 2 and is connected to the handwheel 4 for transmission. The lower end of the valve stem is threaded to the gate plate 5. Therefore, operating the handwheel 4 drives the valve stem 3 to rotate inside the valve cover 2, which in turn drives the gate plate 5 to move up and down to open and close the valve.

[0019] The valve stem 3 rotates by a convex ring that is mounted in the valve cover hole 21 of the valve cover 2 through a radially protruding convex ring in the middle. The upper limit surface of the convex ring is limited by the inner shoulder of the valve cover hole 21 to prevent the valve stem from moving upward axially, and the lower limit surface of the convex ring is limited by the tight ring 6 installed in the valve cover hole 21 to prevent the valve stem from moving downward axially.

[0020] Meanwhile, the valve cover 2 is fixed to the top of the valve body 1 by welding. Specifically, the bottom of the valve cover 2 is provided with a cylindrical positioning cylinder 22. The outer circumference of the positioning cylinder is provided with an upper step surface 23 that extends radially outward. The mounting hole 11 is a round hole that matches the positioning cylinder 22, and a lower step surface 12 that extends radially inward is provided at the top of the mounting hole 11.

[0021] Therefore, the valve cover 2 can be positioned and inserted into the mounting hole 11 on the top of the valve body 1 by the positioning cylinder 22. This ensures that the assembly between the valve cover 2 and the valve body 1 will not be eccentric, and that the upper step surface 23 is in close contact with the lower step surface 12 to form an axial limiting contact surface. The upper step surface 23 and the lower step surface 12 are coaxial annular planes. The axial limiting contact surface formed by the two in close contact is perpendicular to the axis of the valve stem 3. Then, the outer circumferential edge area of ​​the axial limiting contact surface is fixed by an annular weld 7 to ensure the connection and fixation between the valve cover 2 and the valve body 1.

[0022] In addition, the fixing structure of the annular weld 7 is provided with an upper weld position outer chamfer 24 on the outer circumferential edge of the upper step surface 23 and a lower weld position outer chamfer 13 on the outer circumferential edge of the lower step surface 12. The upper and lower weld position outer chamfers are closely attached to each other on the axial limiting contact surface and then merge to form an annular welding groove 8 with a V-shaped cross-section. The annular weld 7 can be formed by welding filling in the annular welding groove.

[0023] Furthermore, the cross-section of the annular welding groove 8 can also be rectangular or trapezoidal or other shapes, but in this embodiment, the welding effect is best achieved by using a V-shaped cross-section.

[0024] Obviously, since this utility model eliminates the threaded connection at the junction of the valve cover 2 and the valve body 1, it simplifies the thread processing process in the metalworking production process and reduces the cost of using tools such as taps and dies. It also eliminates the trouble of periodically tightening the valve cover. In particular, it also omits the application of sealing components such as the orifice gasket, which means that sealing can be achieved without relying on an external sealing ring, making the structural assembly simpler and thus greatly reducing the production cost of the product.

[0025] Of course, the valve cover 2 fixed by the circumferential weld 7 not only ensures the sealing performance, but also prevents the valve cover 2 from being disassembled at will, reduces the risk of human error, and also forms another form of sealing effect.

[0026] The basic principles and main features of this utility model have been described above. Those skilled in the art should understand that this utility model is not limited to the above embodiments. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the utility model as claimed. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A welded gate valve with a valve cover, comprising a valve body (1), a gate plate (5) installed inside the valve body, a valve cover (2) installed in a mounting hole (11) on the top of the valve body, a valve stem (3) installed inside the valve cover, and a handwheel (4) disposed on the top of the valve cover, wherein the handwheel drives the gate plate (5) to open and close the valve via the valve stem (3), characterized in that... The valve cover (2) is provided with a positioning cylinder (22) at the bottom. The outer circumferential surface of the positioning cylinder is provided with an upper step surface (23) extending radially outward. The top of the mounting hole (11) is provided with a lower step surface (12) extending radially inward. The valve cover (2) is positioned and inserted into the mounting hole (11) at the top of the valve body (1) by the positioning cylinder (22), and the upper step surface (23) is closely attached to the lower step surface (12) to form an axial limiting contact surface. The outer circumferential edge area of ​​the axial limiting contact surface is fixed by an annular weld (7).

2. A bonnet welded gate valve according to claim 1, characterized in that The outer circumferential edge of the upper step surface (23) is provided with an upper weld position chamfer (24), and the outer circumferential edge of the lower step surface (12) is provided with a lower weld position chamfer (13). The upper and lower weld position chamfers are joined together after the axial limiting contact surfaces are closely attached to form an annular welding groove (8) with a V-shaped cross-section. The upper step surface (23) and the lower step surface (12) are coaxial annular planes.

3. A bonnet welded gate valve according to claim 2, wherein The annular weld groove (8) is filled with welding to form an annular weld (7).

4. A bonnet welded gate valve as defined in claim 2 wherein The axial limiting contact surface is perpendicular to the axis of the valve stem (3).

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