A valve seat structure for ultra-low temperature top-mounted ball valve

Abstract

A valve seat structure of an ultra-low temperature top-mounted ball valve includes a valve body and a ball body, a valve seat is installed between the two, a spring seat and a positioning nut are installed on the valve seat, and a Z-shaped positioning piece is included; the upper end cross beam of the Z-shaped positioning piece is fixed to the valve body by bolts; and the lower end cross beam of the Z-shaped positioning piece is connected to the positioning nut by a second screw, so that the valve body and the positioning nut are connected as a whole through the Z-shaped positioning piece; the through holes of the bolts and the second screws on the Z-shaped positioning piece are both long strip holes. The valve body and the positioning nut of the present invention are connected through the Z-shaped positioning piece, which effectively prevents the anti-loosening problem of the threaded connection between the positioning nut and the valve seat, and improves the reliability of the valve during use.

Description

Technical Field

[0001] The invention relates to the technical field of valve manufacturing, in particular to an ultra-low temperature top-mounted ball valve seat structure. Background Art

[0002] As a high-quality, efficient, green and clean low-carbon energy, natural gas has been increasing its share in global energy consumption. In recent years, the proportion of LNG in my country's natural gas supply has increased rapidly. With the development of the LNG industry, the localization of key LNG equipment has been fully launched nationwide. Valves with an operating temperature of -196℃~-101℃ are ultra-low temperature valves, and the temperature of natural gas after liquefaction is -162℃. Ultra-low temperature top-entry ball valves, as one of the key equipment for LNG, are still mainly imported in my country. In recent years, some domestic manufacturers and scientific research institutes have been committed to the research of ultra-low temperature top-entry ball valves for LNG, and have also made great achievements.

[0003] Ultra-low temperature top-mounted ball valves for LNG are still relatively difficult for designers, and some key technologies are not yet mature. Among them, the sealing problem between the valve seat and the valve body under ultra-low temperature conditions and the ability to achieve online maintenance of the ball and the valve seat have always been a problem that has troubled technicians. At present, the seal between the valve seat and the valve body mostly uses lip seals, and the lip seals have very high requirements for design, processing, manufacturing, assembly and maintenance: the valve seat with the lip seal installed cannot have a large rotation in the circumferential direction; during assembly or maintenance, the spring seat cannot have a large rotation in the circumferential direction; when the valve is put into use again, the threaded connection between the positioning nut and the valve seat needs to be prevented from loosening. These requirements will directly affect the performance of the valve. Summary of the invention

[0004] The purpose of the present invention is to provide a super-low temperature top-mounted ball valve seat structure, which improves the reliability of valve use.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A super-low temperature top-mounted ball valve seat structure, comprising a valve body and a ball, with a valve seat installed therebetween, a spring seat and a positioning nut installed on the valve seat, comprising a Z-shaped positioning piece; the upper end crossbeam of the Z-shaped positioning piece is fixed to the valve body by bolts; and the lower end crossbeam of the Z-shaped positioning piece is connected to the positioning nut by a second screw, thereby connecting the valve body and the positioning nut as a whole through the Z-shaped positioning piece; the through holes of the bolts and the second screws on the Z-shaped positioning piece are both long strip holes.

[0007] A sliding bearing is installed on the second screw, and the sliding bearing is located in the long strip hole on the Z-shaped positioning piece.

[0008] The valve body and the spring seat are connected by a first screw, a sliding bearing is installed on the head of the first screw, and the sliding bearing is placed in a guide groove on the outer circumference of the spring seat.

[0009] A guide groove is machined on the inner diameter of the spring seat, a guide key is adapted in the guide groove, and the guide key is fixedly connected in the key groove at the matching position of the valve seat (16) and the spring seat.

[0010] The beneficial effects of the present invention are as follows: the valve body and the positioning nut are connected by a Z-shaped positioning piece, which effectively prevents the problem of the positioning nut and the valve seat being threaded and loose, and improves the reliability of the valve during use. The spring seat and the valve body are connected by screws, which effectively prevents the spring seat from rotating; the valve seat and the spring seat are connected by a guide key, which effectively prevents the valve seat from rotating. This structural design facilitates valve assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0012] Figure 2 for Figure 1 A partial enlarged view of the corresponding valve seat assembly;

[0013] In the figure: 1-valve body, 2-upstream valve seat assembly, 3-Z-shaped positioning plate, 4-ball, 5-downstream valve seat assembly, 6-spring seat, 7-first sliding bearing, 8-first screw, 9-bolt, 10-second screw, 11-second sliding bearing, 12-positioning nut, 13-pressure cover, 14-lip sealing ring, 15-guide key, 16-valve seat, 17-third screw, 18-valve seat sealing ring. DETAILED DESCRIPTION

[0014] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings.

[0015] See also Figure 1 A valve seat structure of an ultra-low temperature top-mounted ball valve comprises a valve body 1, a ball 4 is arranged in the middle of the valve body 1, an upstream valve seat assembly 2 and a downstream valve seat assembly 5 are arranged on both sides of the ball 4, the upstream valve seat assembly 2 and the downstream valve seat assembly 5 are symmetrically installed, wherein the upstream valve seat is a one-way sealing structure, and the downstream valve seat is a two-way sealing structure. The upstream and downstream valve seat assemblies mainly include a valve seat and a spring seat and a positioning nut installed on the valve seat. The medium in the ultra-low temperature top-mounted ball valve has flow direction requirements, and it is a DIB-2 type valve seat structure with a self-pressure relief function in the middle cavity.

[0016] Reference Figure 2 ,A sort of Ultra low temperatureThe valve seat structure of the top mounted ball valve includes a valve body and a ball body, a valve seat is installed between the two, and a spring seat and a positioning nut are installed on the valve seat, and also includes a Z-shaped positioning piece 3; the upper end cross beam of the Z-shaped positioning piece 3 is fixed to the valve body 1 by a bolt 9; and the lower end cross beam of the Z-shaped positioning piece 3 is connected to the positioning nut 12 by a second screw 10, so that the valve body 1 and the positioning nut 12 are connected as a whole through the Z-shaped positioning piece 3; the through holes of the bolt 9 and the second screw 10 on the Z-shaped positioning piece 3 are both long strip holes. The outer circumference of the positioning nut 12 is processed into a tooth shape, and a threaded hole is processed in each tooth groove, and the threaded hole connects the Z-shaped positioning piece 3 through the second screw 10.

[0017] A sliding bearing 11 is installed on the second screw 10 and is located in a long strip hole on the Z-shaped positioning piece 3 so that the valve seat can move left and right under the action of the medium pressure with low friction.

[0018] The valve body 1 and the spring seat 6 are connected by a first screw 8, and a sliding bearing 7 is installed on the head of the first screw 8. The sliding bearing 7 is placed in a guide groove on the outer circumference of the spring seat 6. This structure prevents the spring seat 6 from rotating.

[0019] A guide groove is machined on the inner diameter of the spring seat 6, and a guide key 15 is adapted in the guide groove. The guide key 15 is fixed in the key groove at the matching position of the valve seat 16 and the spring seat 6. This structure can prevent the valve seat 16 from rotating when the positioning nut 12 is rotated, thereby damaging the lip seal ring 14. At the same time, in order to prevent the guide key 15 from blowing out of the key groove under the action of the medium pressure, it is fixed to the valve seat by a third screw 17.

[0020] The working principle of the present invention is as follows: the spring seat 6 is prevented from rotating by the first screw 8 fixed on the valve body, and the valve seat 16 is prevented from rotating by the guide key 15. After the valve is assembled as a whole, the positioning nut and the valve body are connected by the Z-shaped positioning piece 3 to prevent the connection thread of the positioning nut from loosening during operation.

Claims

1. A valve seat structure of an ultra-low temperature top-mounted ball valve, comprising a valve body and a ball, a valve seat installed between the two, a spring seat and a positioning nut installed on the valve seat, characterized in that: The invention comprises a Z-shaped positioning piece (3); the upper end cross beam of the Z-shaped positioning piece (3) is fixed to the valve body (1) by means of bolts (9); and the lower end cross beam of the Z-shaped positioning piece (3) is connected by means of a second screw (10) and a positioning nut (12), so that the valve body (1) and the positioning nut (12) are connected as a whole through the Z-shaped positioning piece (3); the through holes of the bolts (9) and the second screws (10) on the Z-shaped positioning piece (3) are both long strip holes; a guide groove is machined on the inner diameter of the spring seat (6), a guide key (15) is adapted in the guide groove, and the guide key (15) is fixed in a keyway at a matching position of the valve seat (16) and the spring seat (6).

2. The ultra-low temperature top-entry ball valve seat structure according to claim 1, characterized in that: A sliding bearing (11) is mounted on the second screw (10), and the sliding bearing (11) is located in the long strip hole on the Z-shaped positioning piece (3).

3. The ultra-low temperature top-entry ball valve seat structure according to claim 1, characterized in that: The valve body (1) and the spring seat (6) are connected by a first screw (8). A sliding bearing (7) is installed on the head of the first screw (8). The sliding bearing (7) is placed in a guide groove on the outer circumference of the spring seat (6).

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