JPH0418179B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention generally relates to an improved plastic lined plug valve that provides long service life with minimal maintenance costs. More particularly, the present invention relates to an improved stem seal suitable for use in such plastic-lined plug valves.

[Conventional technology]

Plug valves have found wide use in handling a variety of fluids. For many applications, a particularly desirable form of plug valve is a so-called plastic-lined plug valve, where the plastic lining provides chemical resistance that is desirable for many applications. Generally, such plugs
The valve has a protruding handle that is fixed to the plug,
This handle rotates the plug, allowing the valve to open and close. Various techniques have been used to provide a seal around the stem of such plug valves. Often such seals require relatively high maintenance costs, and although dynamic seals were often used, these seals tended to leak during initial pressurization. be. Some plastic-lined valves are disclosed in U.S. Pat. No. 3,157,195;
Same No. 3698422; Same No. 3703910 and Same No.
Generally described in No. 3916943. While the plastic-lined valves described in these patents had advantages in terms of reduced seal maintenance costs, they were still unsatisfactory in terms of leakage during pressurization.

[Problem to be solved by the invention]

The present invention provides a plastic-lined plug valve which improves upon the disadvantages of prior art plug valves, namely relatively high seal maintenance costs and leakage when pressurized.
The aim is to provide a valve.

[Means to solve the problem]

The above objects are accomplished by providing a frusto-conical surface between the plug and the stem to provide a seal around the stem of the plug valve. This frusto-conical surface provides a reliable handle seal in combination with the seal and its compression member and minimizes leakage.

The present invention combines the following components (A) commonly found in conventional plug valves with the following features of the present invention:
A plug valve comprising the improved components of (B). More specifically, the present invention provides a plug valve comprising: (A) a first end, a second end, a fluid passageway 15 extending from the first end to the second end, and a valve. A valve body 11 having a synthetic resin material coating with a plug receiving cavity 17 formed by the body and extending substantially perpendicular to the axis of the fluid passageway; a handle 25 disposed within the fluid passageway and extending away from the valve body; a generally planar sealing member 47 disposed adjacent to and above the valve plug;
A bonnet 22 is disposed over the sealing member and secured to the valve body 11 to press the sealing member 47 in sealing engagement with the valve body and define a generally centrally located stem storage passageway larger than the diameter of the stem 25. Plug 1 having a synthetic resin material coating
8; and in a plug valve including a packing foot 27 adjustably positionable in the bonnet and extending around the handle into the passageway of the bonnet; (B) at a location adjacent to the junction of the plug and the handle; 18 defines an annular frusto-conical surface 46 having a larger diameter adjacent the plug and a smaller diameter adjacent the handle;
7 has an opening formed by a flexible sealing portion 53 of sufficient diameter to pass over the handle and an annular frustoconical surface 46, and a large diameter of the frustoconical surface. a generally annular cup seal 55 having a trapezoidal cross-section is disposed against the seal member 47 and has a surface generally parallel to the frusto-conical surface 46; The cup seal 55 is restrained from radial movement by an annular locking ring 49 and is made of a pressure deformable synthetic resin material, with a rigid support ring 58 adjacent the cup seal 55 and adjacent to the valve. This is achieved by a plug valve characterized in that it comprises members 61, 62 which are arranged at a distance from the plug; and which elastically press the support ring 58 towards the valve plug.

〔Example〕

Further detailed features and advantages of the invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings.

FIG. 1 is a longitudinal sectional view of a valve according to the invention.

FIG. 2 is a partial cross-sectional view of the plug bonnet and seal assembly.

In FIG. 1, a longitudinal section of a plastic lined plug valve, designated generally by the numeral 10, is schematically shown. The valve 10 has a valve body 11. This valve 11 has a first end 13
A passage 15 is formed extending between the second end portion 14 and the second end portion 14 . The interior of the body 11 is lined with a plastic lining 16. The body 11 has a plug receiving cavity 17 in which a plastic coated plug 18 is placed.
is formed. As shown in Figure 1, plug 1
8 is in the closed position. The seal member 21 is the plug 1
8 and held in sealing engagement with a portion of lining 16 by valve bonnet 22. Valve bonnet 22 is connected to body 11 by a plurality of bolts 23, only one of which is shown. Valve plug 18 is of tapered shape, with its larger diameter positioned adjacent seal 21 . A plastic-coated handle 25 is attached to the plug 18 adjacent the seal 21. A packing foot 27 is adjustably attached to the bonnet 22 by a plurality of bolts 28, two of which are shown. An operating handle assembly 29 is attached to handle 25. A live-loaded handle seal assembly 31 is located substantially adjacent the handle and plug juncture.

FIG. 2 shows the live load seal assembly 31 of FIG.
A detailed cross-sectional view is shown. The seal assembly 31 includes in cooperative combination a valve plug 41 having a coating 42 of synthetic resin thermoplastic material.
The plug 41 is attached to the handle 25 and has a generally annular recess formed adjacent to the plug 41, into which the covering material 42 of the plug 41 is inserted.
A portion 45 is arranged. At a location adjacent the plug and handle and sheathing portion 45 , sheathing 42 forms a generally annular frustoconical sealing surface 46 . Surrounding the handle 25 and adjacent the frustoconical surface is a generally flat sealing member 47. This seal member 47 is substantially equivalent to the seal member 21 of FIG. 1, and is fixed to the valve body by the bonnet 22 during operation. Seal member 47 forms a generally annular locking ring 49 with a generally cylindrical surface 51 facing towards handle 25 . There is a thin flexible portion of the seal 47 that forms a flexible seal portion 53 that conforms to the frusto-conical sealing surface 46 within the locking ring 49 of the seal 47 . In a preferred embodiment of the invention, flexible sealing portion 53 is lip-shaped and may hereinafter be referred to as sealing lip 53. Adjacent to seal lip 53 and remote from plug 41 is a cup seal 55, such as seal 47, made of a flexible synthetic resin. This cup seal has an approximately annular shape and a trapezoidal cross section, and has four faces.
6 and spaced apart from surface 46 to cup seal 55. Disposed on the cup seal 55 away from the face 56 is a cup seal support ring 58, preferably made of a metal such as steel and having an annular shape with a diameter approximating the diameter of the cup seal. .
Adjacent to support ring 58 is a first conical spring washer 61, often referred to as a Belleville spring, which engages support ring 58 away from the cup seal. A second conical spring washer 62 is spaced from support ring 58 and in contact with washer 61. A thrust washer 64 is disposed about the handle 44 and engages a second washer 62 at a location remote from the support ring 58. This thrust washer 64 has a substantially cup-like shape, and includes a conical spring washer, a support ring 58,
It surrounds a cup seal 55 and an annular locking ring 49 generally adjacent the seal member 47 .
This thrust washer 64 forms a seal-engaging annular flange 65. Adjacent to thrust washer 64 and separate from conical spring washer 62 is an antistatic washer 66 which engages the metal of the handle to provide electrical contact with the handle. This antistatic washer 66 is held in place by a packing foot 27.

Valves according to the invention can be easily manufactured using a wide variety of materials. Most commonly, malleable iron and steel are used for the body, bonnet, packing foot, and plug. The body is generally lined by well-known injection molding methods, but
The plug is also coated by injection molding. The shape of the plug is usually not important. Figures 1 and 2
The configuration shown is commonly referred to as a putter plug, and when in the closed position as shown in FIG. 1, the plug is released 180 degrees to each side and leaves the central vein. Alternatively, the plug may be made of a more conventional design in which a passageway is formed within the plug that extends approximately perpendicular to the generation axis. Once the plug is coated by injection molding, the outer surface is machined to the desired dimensions. Advantageously, surfaces with a roughness of 8 to 16 micron inches have been found to be very satisfactory. Advantageously, the truncated conical surface when projected onto the shaft of the handle forms an angle of 80 to 45 degrees with the shaft, preferably 55 to 45 degrees.
form a 65 degree angle. The seals 21, 47 are preferably produced by machining. Seal 4 in Figure 2
The sealing lip 53 of 7 is advantageously relatively thin, for example 0.25 to 0.65 mm, which serves the purpose. Cup seal 55 is preferably manufactured from a flexible synthetic resin material. Particularly desirable materials for these seals, liners, and plug coverings include fluorocarbon polymers, polytetrafluoroethylene,
Examples include polyvinyl fluoride, polyvinylidene fluoride, vinylidene chloride polymer, low-density polyethylene, polyisoptylene, perfluoroalkoxy resin, natural rubber, and perbunan. The plug valve according to the invention provides a greatly improved operating life with minimal leakage and minimal maintenance costs.

As is clear from the above description, the present invention can be embodied in various changes and modifications different from those specifically described in the above description. For this reason, the above description is by way of example only and should not be considered or construed as limiting or limiting the invention, which is limited only by the scope of the claims. be.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a valve according to the invention. FIG. 2 is a partial cross-sectional view of the plug bonnet and seal assembly. In the figure; 11... Valve body; 13...
First end; 14... Second end; 15... Passage; 1
6... Plastic lining; 17... Plug storage cavity; 18... Plug; 21... Seal; 22...
...Bonnet; 23, 28... Bolt; 25...
Handle; 27...Packing foot; 29...Handle assembly; 31...Seal assembly; 41...Plug; 42...Coating; 44...Handle; Member; 49...Lock ring; 53...Flexible seal portion (sometimes called seal lip); 55...Cup seal;
58... Support ring; 61, 62... Conical spring
Washer; 64... Thrust washer; 66...
Anti-static washers.

Claims (1)

[Claims] 1. A first end and a second end, from the first end to the second end.
A valve body 11 having a synthetic resin material coating with a fluid passageway 15 extending at the end and a plug receiving cavity 17 formed by the valve body and extending substantially perpendicular to the axis of the fluid passageway; a handle 25 extending apart, a generally planar sealing member 47 disposed adjacent to the handle and above the valve plug, a generally planar sealing member 47 disposed over the sealing member and secured to the valve body 11 in sealing engagement with the valve body; a plug 18 having a synthetic resin material coating comprising a bonnet 22 which presses against the sealing member 47 in relation and forms a generally centrally located shank receiving passageway larger than the diameter of the shank 25; In a plug valve including a packing foot 27 which extends into the bonnet passage around the plug; the plug 18 has a large diameter adjacent the plug and a small diameter adjacent the handle at a location adjacent the plug-handle junction; forming an annular frusto-conical surface 46 having a diameter; a flexible sealing portion 53 that is centrally located and conforms to the annular frusto-conical surface 46 of sufficient diameter for the sealing member 47 to pass over the handle therein; a locking ring 4 having an aperture formed by
9; a cup seal 55 of generally annular shape with a trapezoidal cross section is disposed against the sealing member 47 and has a surface substantially parallel to the frustoconical surface 46; Radial movement is restrained by an annular locking ring 49 and made of pressure deformable synthetic resin material, and a rigid support ring 58
is located adjacent to the cup seal 55 and at a distance from the valve plug; and is characterized in that it comprises members 61, 62 for elastically compressing the support ring 58 towards the valve plug. Plug valve. 2. The valve according to claim 1, wherein the synthetic resin material is a fluorocarbon polymer. 3. The valve according to claim 1 or 2, wherein the annular locking ring 49 is integral with the sealing member 47. 4. The element for elastically tensioning the rigid support ring 58 adjacent the cup seal 55 towards the valve plug 41 comprises at least one conical spring washer 61, 62. The valve according to item 2 or 3. 5. A valve according to any one of claims 1 to 4, comprising a washer 66 for providing an electrical connection between the valve handle 25 and the bonnet 22. 6. The valve according to any one of claims 1 to 5, wherein the truncated conical surface 46 forms an angle of 55 to 65 degrees with the handle when it projects toward the rotational axis of the handle 25.