Ultralow-temperature top-mounted ball valve

Abstract

The utility model relates to the technical field of ball valves, and provides an ultralow-temperature top-mounted ball valve which comprises a valve body with an opening in the top, a stuffing box connected to the opening of the valve body, a valve rod rotatably arranged in the stuffing box, extending into the valve body and connected with a ball body, valve seats arranged between the two sides of the ball body and the valve body, and limiting steps arranged at the bottoms of the valve seats. The top of the valve seat is connected with a pressing ring through a fastener, an annular area for installing the valve seat is formed between the limiting step and the pressing ring, the valve seat is well limited from moving up and down, it is guaranteed that the valve seat is effectively fixed, and it is guaranteed that the valve is effectively sealed; and the valve seat can be taken down or installed by removing the pressing ring, so that installation and maintenance are more convenient.

Description

Technical Field

[0001] The utility model relates to the technical field of ball valves, in particular to an ultra-low temperature top-mounted ball valve. Background Art

[0002] Ultra-low temperature top-entry ball valves are widely used in small pipeline systems in ultra-low temperature liquefied natural gas industry projects, and are also used in ultra-low temperature liquefied gases such as liquid nitrogen, liquid hydrogen, and liquid argon.

[0003] At present, there are usually two ways to install the valve seat in ultra-low temperature top-mounted ball valves. One is that the valve seat is directly pressed between the ball and the valve body, and the other is that the valve seat is embedded in a groove on the valve body. However, the former method is easy to deform the valve seat under the alternating working conditions of ultra-low temperature and normal temperature, which can easily cause the valve seat to move up and down and cause sealing failure; the latter method will bring certain difficulties to disassembly and assembly, and it is inconvenient to install and maintain. Utility Model Content

[0004] The utility model aims to provide an ultra-low temperature top-mounted ball valve to solve the above-mentioned defects of the prior art.

[0005] The embodiments of the present invention are implemented by the following technical solutions:

[0006] A super-low temperature top-mounted ball valve has a valve body with an open top, a stuffing box connected to the open part of the valve body, a valve stem rotatably arranged in the stuffing box, the valve stem extends into the valve body and is connected to a ball, valve seats are arranged between the two sides of the ball and the valve body, a limiting step is arranged at the bottom of the valve seat, a pressure ring is connected to the top of the valve seat via a fastener, and an annular area for installing the valve seat is formed between the limiting step and the pressure ring.

[0007] Optionally, a pre-tightening assembly is provided between the valve seat and the valve body on at least one side, and the pre-tightening assembly includes a pre-tightening spring and a spring seat which are sequentially arranged in a direction close to the valve seat.

[0008] Optionally, the preload spring is a disc spring.

[0009] Optionally, a support seat for supporting the ball is provided at the bottom of the valve seat, and a fixing ring is connected to the bottom of the stuffing box, and the fixing ring and the support seat jointly limit the position of the ball.

[0010] Optionally, a limiting boss is provided on the valve stem, a groove for accommodating the limiting boss is provided on the stuffing box, and thrust bearings are provided at both axial ends of the limiting boss.

[0011] Optionally, a drip tray is provided on the outside of the stuffing box, and the diameter of the drip tray is larger than the maximum diameter of the stuffing box.

[0012] Optionally, a sealing assembly is provided between the stuffing box and the valve stem.

[0013] The technical solution of the present invention has at least the following advantages and beneficial effects: in the present invention, the pressure ring is connected by fasteners so that the pressure ring is removable, and an annular area for installing the valve seat is formed between the pressure ring and the limiting step. Such an arrangement, on the one hand, effectively limits the up and down movement of the valve seat, ensures the effective fixation of the valve seat, and ensures the effective sealing of the valve; on the other hand, the valve seat can be removed or installed by removing the pressure ring, making installation and maintenance more convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the utility model and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying creative work.

[0015] Figure 1 A schematic diagram of the structure of an ultra-low temperature top-mounted ball valve provided by the utility model;

[0016] Figure 2 for Figure 1 A magnified image of point A;

[0017] Figure 3 for Figure 1 The enlarged view of point B;

[0018] Icon: 1-valve body, 2-stuffing box, 3-valve stem, 301-limiting boss, 4-ball, 5-valve seat, 6-pressure ring, 7-preload spring, 8-spring seat, 9-support seat, 10-fixing ring, 11-thrust bearing, 12-drip tray. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Generally, the components of the embodiments of the utility model described and shown in the drawings here can be arranged and designed in various different configurations.

[0020] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the present invention to be protected, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] In the description of the present invention, it should be noted that if the terms "upper" and "lower" appear to indicate an orientation or position relationship, they are based on the orientation or position relationship shown in the accompanying drawings, or are the orientation or position relationship in which the product of the application is usually placed when in use. This is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0022] refer to Figure 1-3 A super-low temperature top-mounted ball valve has a valve body 1 with an open top, a stuffing box 2 is connected to the open part of the valve body 1, the valve body 1 is integral, the stuffing box 2 is connected to the valve body 1 by bolts (or screws), and the stuffing box 2 serves as a valve cover. Compared with a split-type top-mounted valve, in the integral structure, the seal at the connection between the valve body 1 and the valve cover will not be affected by the tensile stress of the pipeline.

[0023] A drip tray 12 is provided on the outside of the stuffing box 2, and the diameter of the drip tray 12 is larger than the maximum diameter of the stuffing box 2, that is, the diameter of the drip tray 12 is larger than the diameter of the connecting flange of the stuffing box 2, so as to prevent dripping water from entering the connecting gap between the stuffing box 2 and the valve body 1 and corroding the sealing component, thereby causing low-temperature energy loss and freezing.

[0024] A valve stem 3 is rotatably arranged in the stuffing box 2. Specifically, a bearing is arranged between the valve stem 3 and the stuffing box 2 to ensure smooth rotation of the valve stem 3. A sealing assembly is arranged between the stuffing box 2 and the valve stem 3. The sealing assembly can adopt a combination of commonly used packing seals and O-ring seals, etc., which is not limited in this embodiment. The valve stem 3 extends into the valve body 1 and is connected to the ball 4. The connection method between the ball 4 and the valve stem 3 can be a commonly used method in the art. For example, a groove is arranged on the top of the ball 4, and a protrusion is arranged on the bottom of the valve stem 3 to match it. It should be understood that the cross-section of the protrusion and the groove should be a polygonal structure, such as a rectangle.

[0025] It is worth noting that in the prior art, after the valve stem 3 is installed, the valve stem 3 pushes the ball 4 downward, and the ball 4 will squeeze the soft sealing valve seat 5 downward, increasing the risk of damaging the valve seat 5. For this reason, in this embodiment, a limiting boss 301 is provided on the valve stem 3, and the stuffing box 2 is provided with a groove for accommodating the limiting boss 301. Both axial ends of the limiting boss 301 are provided with thrust bearings 11. This arrangement limits the axial position of the valve stem 3 to prevent it from squeezing the valve seat 5 downward, which solves the above problem well. It is easy to understand that on this basis, a certain gap should be left between the raised end face at the bottom of the valve stem 3 and the bottom face of the groove at the top of the ball 4 to avoid over-positioning.

[0026] In this embodiment, a support seat 9 for supporting the ball 4 is provided at the bottom of the valve seat 5, and a fixing ring 10 is connected to the bottom of the stuffing box 2. Specifically, the fixing ring 10 is provided with a limiting spherical surface that can fit with the top of the ball 4. The fixing ring 10 and the support seat 9 jointly limit the position of the ball 4. With this arrangement, the valve can be installed in all directions, the position of the ball 4 can remain unchanged, and the valve can maintain a good seal.

[0027] Valve seats 5 are provided between the two sides of the sphere 4 and the valve body 1, and a limiting step is provided at the bottom of the valve seat 5. The top of the valve seat 5 is connected with a pressing ring 6 by a fastener so that the pressing ring 6 can be removed. The fastener is preferably a screw. An annular area for installing the valve seat 5 is formed between the limiting step and the pressing ring 6. Such an arrangement, on the one hand, effectively limits the up and down movement of the valve seat 5, ensures the effective fixation of the valve seat 5, and ensures the effective sealing of the valve; on the other hand, the valve seat 5 can be removed or installed by removing the pressing ring 6, which makes installation and maintenance more convenient.

[0028] In addition, in the prior art, since the seal between the valve seat 5 and the ball 4 is in direct contact, the valve seat 5 is forced to seal. After a period of time of switching under ultra-low temperature conditions, the valve seat 5 is worn and the valve is prone to failure. For this reason, this embodiment provides a pre-tightening component between the valve seat 5 on one side and the valve body 1. The pre-tightening component includes a pre-tightening spring 7 and a spring seat 8 arranged in sequence in the direction close to the valve seat 5. The pre-tightening component can provide a pre-tightening force for the valve seat 5, which solves the above problem well. Of course, in other embodiments, the above pre-tightening components can also be provided at the valve seats 5 on both sides.

[0029] Furthermore, the preload spring 7 is a disc spring, which is convenient for application in small-diameter valves and in situations where the installation space is small. Of course, in other embodiments, if there is no limitation on this factor, the preload spring 7 can also be a cylindrical spring.

[0030] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may be subject to various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A cryogenic top-mounted ball valve, comprising a valve body (1) with an open top, a stuffing box (2) connected to the open portion of the valve body (1), a valve stem (3) rotatably arranged in the stuffing box (2), the valve stem (3) extending into the valve body (1) and connected to a ball (4), valve seats (5) being arranged between both sides of the ball (4) and the valve body (1), characterized in that: A limiting step is provided at the bottom of the valve seat (5), and a pressing ring (6) is connected to the top of the valve seat (5) via a fastener, and an annular area for mounting the valve seat (5) is formed between the limiting step and the pressing ring (6).

2. The ultra-low temperature top-entry ball valve according to claim 1, characterized in that: A pre-tightening assembly is provided between the valve seat (5) and the valve body (1) on at least one side, and the pre-tightening assembly comprises a pre-tightening spring (7) and a spring seat (8) which are arranged in sequence along a direction close to the valve seat (5).

3. The ultra-low temperature top-entry ball valve according to claim 2, characterized in that: The preload spring (7) is a disc spring.

4. The ultra-low temperature top-entry ball valve according to claim 1, characterized in that: A support seat (9) for supporting the ball (4) is provided at the bottom of the valve seat (5), and a fixing ring (10) is connected to the bottom of the stuffing box (2). The fixing ring (10) and the support seat (9) jointly limit the position of the ball (4).

5. The ultra-low temperature top-entry ball valve according to claim 1, characterized in that: The valve stem (3) is provided with a limiting boss (301), the stuffing box (2) is provided with a groove for accommodating the limiting boss (301), and thrust bearings (11) are provided at both axial ends of the limiting boss (301).

6. The ultra-low temperature top-entry ball valve according to claim 1, characterized in that: A drip tray (12) is provided on the outside of the stuffing box (2), and the diameter of the drip tray (12) is greater than the maximum diameter of the stuffing box (2).

7. The ultra-low temperature top-entry ball valve according to claim 1, characterized in that: A sealing component is provided between the stuffing box (2) and the valve stem (3).

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