Novel forced sealing plug valve

Abstract

The utility model belongs to the field of valves, and particularly relates to a novel forced sealing plug valve which comprises a valve body, a valve rod, a plug body and a transmission device, the plug body is of a regular cone structure, and the center of the upper end face of the plug body is connected with the transmission device on a support through the valve rod. The upper end of the valve rod is matched and connected with an internal thread of a screw sleeve through an external thread; the screw sleeve is fixedly connected with a transmission shaft of a transmission device; a driving guide device is arranged between the outer circle face of the valve rod and the support, the driving guide device is composed of a guide groove in the outer circle face of the valve rod and a guide pin fixedly installed on the support in a matched mode, and the guide groove is composed of a 90-degree arc groove in the circumferential direction and an axial groove in the upward direction of the tail end of the arc groove. Friction-free opening and closing between the cock body and the valve seat sealing face of the inner cavity of the valve body are achieved, the opening and closing torque and abrasion of the sealing face are reduced, the configuration cost of a driving device is reduced, the sealing performance is improved, and the service life of a product is prolonged.

Description

Technical Field

[0001] The utility model belongs to the field of valves, and in particular relates to a hard-sealed plug valve. Background Art

[0002] The plug valve is composed of a valve body, a valve cover, a valve stem, a plug body and a transmission device. The plug body is a conical structure and is installed in the conical valve cavity of the valve body. The transmission device drives the plug body to rotate 90 degrees through the valve stem to realize the opening and closing operation. In high-temperature and abrasive medium working conditions, the plug body and the valve seat sealing surface of the inlet and outlet channels of the valve body adopt a hard sealing structure to ensure that the sealing pair has high temperature resistance and wear resistance. However, the existing hard-sealed plug valve is composed of a sealing pair formed by pressing the plug body and the valve seat sealing surface in the inner cavity of the valve body. During the opening and closing process, there is a large friction between the plug body and the valve seat sealing surface, and the opening and closing torque and sealing surface wear are very large, which affects the sealing performance and service life of the product; in the closed state, the plug body is pushed by the medium pressure to press the outlet side valve seat seal, so the sealing pressure ratio of the inlet side sealing pair is very low, and only one-side sealing on the outlet side can be achieved. Summary of the invention

[0003] The utility model aims at the deficiencies in the prior art and provides a new forced sealing plug valve which is disengaged from the sealing surface of the valve seat during the opening and closing process, reduces the wear of the sealing surface, and can realize double shut-off sealing of the sealing pairs on both sides of the inlet and outlet after closing. It has the advantages of small opening and closing torque, good sealing performance and long service life.

[0004] The technical solution of the utility model is:

[0005] A novel forced-seal plug valve comprises a valve body, a valve stem, a plug body and a transmission device. The plug body is a right cone structure, and the center of its upper end face is connected to the transmission device on the bracket through the valve stem. Its characteristics are: the upper end of the valve stem adopts an external thread to match the internal thread of the screw sleeve, and the screw sleeve is fixedly connected to the transmission shaft of the transmission device; a driving guide device is provided between the outer cylindrical surface of the valve stem and the bracket, and the driving guide device is composed of a guide groove on the outer cylindrical surface of the valve stem and a guide pin fixedly installed on the bracket, and the guide groove is composed of a 90º arc groove in the circumferential direction and an axial groove in the upward direction at the end of the arc groove.

[0006] In the above technical solution, the valve stem consists of a plug rod and an inner valve stem, the lower end of the plug rod is fixedly connected to the center of the upper end surface of the plug body, and the upper end is fixedly connected to the lower end of the inner valve stem through a connecting pin.

[0007] In the above technical solution, a conical elastic sliding piece cooperating with the plug body is arranged in the inner cavity of the valve body, and the outer circumferential surface of the conical elastic sliding piece is fixedly sealed and embedded in the inner cavity of the valve body.

[0008] In the above technical solution, an automatic pressure relief device is arranged in the cavity between the upper and lower end surfaces of the plug body and the valve body, and the automatic pressure relief device is composed of a pressure relief pipe arranged between the inner cavity of the valve body on the upper and lower sides of the plug body and the valve body inlet channel.

[0009] In the above technical solution, the valve body adopts a split structure consisting of a valve body main body and an upper end cover and a lower end cover. The upper end cover and the lower end cover are respectively fixed and sealed on the upper end face and the lower end face of the valve body main body by bolts.

[0010] Compared with the prior art, the utility model has the following beneficial effects: a driving guide device is provided on the outer cylindrical surface of the valve stem, which is composed of a 90° arc groove and an axial groove and cooperates with a guide pin on the bracket. When opening, the guide pin is first located in the axial groove, the valve stem drives the plug body to lift, and then the guide pin enters the arc groove, and the valve stem drives the plug body to rotate; when closing, the guide pin is first located in the arc groove, the valve stem drives the plug body to rotate, and then the guide pin enters the axial groove, and the valve stem drives the plug body to move down and press and seal with the valve seat sealing surface in the inner cavity of the valve body. Frictionless opening and closing between the plug body and the valve seat sealing surface in the inner cavity of the valve body is achieved, the opening and closing torque and the wear of the sealing surface are reduced, the configuration cost of the drive device is reduced, and the sealing performance and product service life are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a structural schematic diagram of the utility model.

[0012] Figure 2 This utility model Figure 1 Schematic diagram of the structure between the middle valve stem and the bracket.

[0013] Figure 3 This utility model Figure 2 Schematic diagram of the structure of the middle guide groove.

[0014] In the figure: 1 valve body, 2 lower end cover, 3 upper end cover, 4 plug body, 5 sealing ring, 6 conical elastic slide, 7 plug rod, 8 sealing ring, 9 wire-wrapped gasket, 10 packing, 11 pressure relief pipe, 12 packing gland, 13 connecting pin, 14 bracket, 15 inner valve stem, 16 rolling bearing, 17 mounting plate, 18 transmission device, 19 connecting sleeve, 20 guide pin, 21 arc groove, 22 axial groove. DETAILED DESCRIPTION

[0015] like Figure 1The new forced sealing plug valve shown in the figure comprises a valve body, a valve stem, a plug body 4 and a transmission device 18. The plug body 4 is a right cone structure, the center of its upper end face is connected to the transmission device 18 on the bracket 14 through the valve stem, and the outer cone surface cooperates with the valve seat sealing surface of the inner cavity of the valve body to form a sealing pair. The right cone is a cone whose upper end face diameter is larger than the lower end face diameter; its characteristics are: the upper end of the valve stem adopts an external thread to cooperate with the internal thread of the screw sleeve, and the outer cylindrical surface of the screw sleeve is transmission-connected with the transmission device 18; a driving guide device is provided between the outer cylindrical surface of the valve stem and the bracket 14, and the driving guide device is composed of a guide groove on the outer cylindrical surface of the valve stem and a guide pin 20 fixedly installed on the bracket 14, and the guide groove is composed of a circular arc groove 21 of 90° in the circumferential direction and an axial groove 22 located at the end of the circular arc groove 21 in the upward direction, as shown in FIG. Figure 2 , Figure 3 As shown. In the closed state, the guide pin 20 is located at the upper end of the axial groove 22, and in the valve open state, the guide pin 20 is located at the left end. In the initial stage of valve opening, the transmission device 18 drives the screw sleeve to rotate, and the valve stem rises in the screw sleeve under the guidance of the guide pin 20, driving the plug body 4 to rise, so that the plug body 4 is out of contact with the valve seat sealing surface in the inner cavity of the valve body. When the guide pin 20 is located at the lower end of the axial groove 22, the rotation of the screw sleeve drives the valve stem to rotate 90º together, aligning the inner hole of the plug body 4 with the inlet and outlet channels of the valve body, and opening the valve. At this time, the guide pin 20 is located at the left end of the arc groove 21; similarly, when the valve is closed, the plug body 4 first rotates 90º, and then moves down to press and fit with the valve seat sealing surface in the inner cavity of the valve body. Frictionless opening and closing is achieved, and the opening and closing torque is small. The transmission device 18 can be equipped with a relatively low-power electric actuator or pneumatic actuator, which reduces product costs and improves sealing performance and product service life.

[0016] The valve stem is composed of a plug rod 7 and an inner valve stem 15. The lower end of the plug rod 7 is fixedly connected to the center of the upper end surface of the plug body 4, and the upper end is fixedly connected to the lower end of the inner valve stem 15 through a coupling. The coupling is composed of a connecting sleeve 19 and a connecting pin 13. The outer cylindrical surface of the lower end of the inner valve stem 15 is tightly connected to the upper part of the inner hole of the connecting sleeve 19. The upper end of the plug rod 7 is fixedly connected to the lower part of the inner hole of the connecting sleeve 19 through the connecting pin 13. The guide groove is set on the outer cylindrical surface of the connecting sleeve 19.

[0017] The technical effect of this technical feature is that the drive guide device is arranged between the connecting sleeve 19 and the bracket, which can ensure the matching position accuracy between the guide groove and the guide pin 20 and improve the guiding accuracy of the drive guide device.

[0018] A conical elastic slide 6 cooperating with the plug body 4 is arranged in the valve body cavity. The outer circumferential surface of the conical elastic slide 6 is fixedly sealed and embedded in the valve body cavity. Sealing rings 5 ​​are respectively arranged between the upper and lower ends of the outer circumferential surface of the conical elastic slide 6 and the wall of the valve body cavity.

[0019] The technical effect produced by this technical feature is that, by utilizing the wedge-shaped fit between the plug body 4 and the conical elastic slide 6, when the valve is closed, the plug body 4 wedges the conical elastic slide 6 to seal, thereby achieving double-shutoff forced sealing of the inlet and outlet sealing pairs and improving the sealing performance.

[0020] An automatic pressure relief device is arranged in the cavity between the upper and lower end surfaces of the plug body 4 and the upper and lower walls of the inner cavity of the valve body. The automatic pressure relief device is composed of a pressure relief pipe 11 arranged between the inner cavity of the valve body on the upper and lower sides of the plug body 4 and the valve body inlet channel.

[0021] The technical effect of this technical feature is that when the valve is closed, the high pressure in the cavity caused by the temperature rise can be automatically discharged to the inlet channel through the pressure relief pipe 11, thereby improving safety.

[0022] The valve body is a split structure consisting of a valve body main body 1 and an upper end cover 3 and a lower end cover 2. The upper end cover 3 and the lower end cover 2 are respectively fixed and sealed on the upper end face and the lower end face of the valve body main body 1 by bolts. Wire-wrapped gaskets 9 are respectively arranged between the radial annular planes of the upper end cover 3 and the lower end cover 2 and the upper and lower end faces of the valve body main body 1. Sealing rings 8 are respectively arranged between the inner cylindrical surfaces of the radial annular planes of the upper end cover 3 and the lower end cover 2 and the inner circular wall of the valve body main body 1, forming a double sealing structure between the valve body main body 1 and the upper end cover 3 and the lower end cover 2.

[0023] The technical effect produced by this technical feature is that, by adopting a two-way opening structure design at the top and bottom, after the pipeline is depressurized and emptied, the internal components can be repaired and replaced on site without removing them from the pipeline, making maintenance convenient.

[0024] A packing 10 is arranged between the upper end cover 3 and the plug rod 7, and the packing 10 is pressed and installed in the packing cavity between the upper end cover 3 and the plug rod 7 by a packing gland 12. A rolling bearing 16 is arranged between the inner valve stem 15 and the bracket 14, and the rolling bearing 16 is pressed between the inner valve stem 15 and the inner hole of the bracket 14 by a mounting plate 17, and a transmission device 18 is installed in the upper plane of the mounting plate 17.

[0025] The “upper”, “lower”, “left” and “right” described in the present invention are directions in the accompanying drawings and should not be regarded as limitations on the present invention.

Claims

1. A novel forced sealing plug valve, comprising a valve body, a valve stem, a plug body (4) and a transmission device (18), wherein the plug body (4) is a right circular cone structure, the center of the upper end surface of which is connected to the transmission device (18) on the bracket (14) through the valve stem, and the outer cone surface and the valve seat sealing surface in the inner cavity of the valve body cooperate with each other to form a sealing pair; Its characteristics are: The upper end of the valve stem is connected to the inner thread of the screw sleeve by an external thread, and the outer cylindrical surface of the screw sleeve is connected to the transmission device (18) in a transmission manner. A driving guide device is provided between the outer cylindrical surface of the valve stem and the bracket (14), and the driving guide device is composed of a guide groove on the outer cylindrical surface of the valve stem and a guide pin (20) fixedly installed on the bracket (14) that cooperates with each other. The guide groove is composed of a circular arc groove (21) with a circumferential angle of 90° and an axial groove (22) located at the end of the circular arc groove (21) in an upward direction.

2. The novel forced sealing plug valve according to claim 1, Its characteristics are: The valve stem is composed of a plug rod (7) and an inner valve rod (15). The lower end of the plug rod (7) is fixedly connected to the center of the upper end surface of the plug body (4), and the upper end is fixedly connected to the lower end of the inner valve rod (15) via a coupling.

3. The novel forced sealing plug valve according to claim 1 or 2, Its characteristics are: A conical elastic sliding piece (6) that cooperates with the plug body (4) is arranged in the inner cavity of the valve body, and the outer circumferential surface of the conical elastic sliding piece (6) is fixedly and sealingly embedded in the inner cavity of the valve body.

4. The novel forced sealing plug valve according to claim 3, Its characteristics are: An automatic pressure relief device is arranged in the cavity between the upper and lower end surfaces of the plug body (4) and the upper and lower walls of the inner cavity of the valve body. The automatic pressure relief device is composed of a pressure relief pipe (11) arranged between the inner cavity of the valve body on the upper and lower sides of the plug body (4) and the inlet channel of the valve body.

5. The novel forced sealing plug valve according to claim 1 or 2, Its characteristics are: An automatic pressure relief device is arranged in the cavity between the upper and lower end surfaces of the plug body (4) and the upper and lower walls of the inner cavity of the valve body. The automatic pressure relief device is composed of a pressure relief pipe (11) arranged between the inner cavity of the valve body on the upper and lower sides of the plug body (4) and the inlet channel of the valve body.

6. The novel forced sealing plug valve according to claim 1, 2 or 4, Its characteristics are: The valve body is a split structure consisting of a valve body main body (1), an upper end cover (3) and a lower end cover (2). The upper end cover (3) and the lower end cover (2) are respectively fixed and sealed on the upper end surface and the lower end surface of the valve body main body (1) by bolts.

7. The novel forced sealing plug valve according to claim 5, Its characteristics are: The valve body is a split structure consisting of a valve body main body (1), an upper end cover (3) and a lower end cover (2). The upper end cover (3) and the lower end cover (2) are respectively fixed and sealed on the upper end surface and the lower end surface of the valve body main body (1) by bolts.

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