JP2000161505A - Eccentric rotary valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a good sealing property for long period with a simple structure by arranging a seat ring whose center part is formed of a rubber elastic body, covering a part which is brought into contact with at least a fluid of a surface of the rubber elastic body with a seat made of polytetrafluoroethylene, and arranging a lip part which is annularly protruded to an inner circumferential surface. SOLUTION: A seat ring 31 is composed of a rubber elastic body 33 fixed to an inner surface of a stainless made angle shaped mandrel 32, and a polytetrafluoroethylene(PTFE) made seat 34 stuck on the surface of the rubber elastic body 33 with special adhesive. A lip part 39 is arranged on an inner circumferential surface by annularly protruding. In the case where it is held in a valve box by a holding member, sealing property with the valve box is surely improved by compression force of the lip part 39. Thus the frictional resistance with a valve element is so small to produce excellent opening/closing operability of a valve, and manufacture is easy without increasing the number of part items, and excellent sealing durability is available.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a valve body in which a rotation shaft of a valve body rotates eccentrically from the center of curvature of a sealing surface of a valve body abutting on a seat ring mounted in a valve box. It relates to an eccentric rotary valve in which a sealing surface is in close contact with the seat ring and the sealing surface of the valve element rotates so as to separate from the seat ring when the valve is opened. The sealing property is good and the valve element can be easily opened and closed. About things.

[0002]

2. Description of the Related Art Conventionally, as a seat ring used for a valve in which a valve element such as a ball valve rotates in a valve box, a single polytetrafluoroethylene resin (trade name: Teflon, hereinafter referred to as PTFE) or nitrile rubber is usually used. Is used. Also, as shown in FIG. 6, in the eccentric rotary valve in which the rotation axis of the valve element rotates eccentrically from the center of curvature of the valve element sealing surface that comes into contact with the seat ring mounted in the valve box, An eccentric rotary valve is known in which a sheet holding member 93 that slides back and forth is provided, a seat ring 9 made of PTFE is held by the sheet holding member 93, and a disc spring 92 is mounted on the back surface thereof.

[0003]

In the eccentric rotary valve, the rotary shaft of the valve element is eccentrically rotated from the center of curvature of the seal surface of the valve element abutting on the seat ring mounted in the valve box, and rotates when the valve is closed. Has a structure in which the sealing surface of the valve element is in close contact with the seat ring in the valve box, and when the valve is opened, the sealing surface of the valve element rotates so as to separate from the seat ring. Therefore, when the valve is closed, when the rotational force of the valve body is increased, a strong pressure is applied to the seat ring, thereby increasing the sealing performance. On the other hand, a large surface pressure is applied to the seat ring, thereby increasing the compression load of the seat ring.

[0004] A single PTFE seat ring is often used for a ball valve or the like, but has a high expansion coefficient and is relatively hard. Therefore, if the seat ring is restrained, it expands at a high temperature and presses the valve body. There is a problem in that the valve is restricted, and the rotational torque of the valve body is increased, making opening and closing difficult. In addition, PTFE has a problem in creep resistance. For example, when the seat ring is thermally expanded in a state where the seat ring is in contact with the valve body, or when the seat ring is compressed by the fluid pressure in the closed state of the valve body, the outer periphery of the valve body is reduced. There is a problem that a creep phenomenon that causes plastic deformation in a state of flowing on the surface occurs and the sealing property is impaired. Although a single rubber seat ring is rich in elasticity and excellent in sealability, it has a problem in chemical resistance, and there is a problem in ensuring long-term sealability in conformity with various fluids. Also, if the valve is closed for a long period of time with a large coefficient of friction and excessive compressive force applied, the seat ring and the valve will stick,
There is a problem that the seat ring creeps and loses its elasticity, thus impairing the sealing performance.

Therefore, as shown in FIG. 6, the seat member 93 on which the seat ring 9 is mounted is slid back and forth in the valve box, so that even if a strong rotational force is applied to the valve body when the valve is closed, the seat member back surface can be used. An eccentric rotary valve structure is used in which only an appropriate sealing surface pressure is always applied to the seat ring 9 by the disc spring 92. However, in this structure, the seat holding member 93 must be slidable in a sealed state on the inner surface of the valve box, and a seal packing 91, a disc spring 92, a seat holding member 93, and a retaining ring 94 for preventing back leakage are provided. And the like, the number of parts is large, and a complicated seal structure must be used. SUMMARY OF THE INVENTION An object of the present invention is to provide an eccentric rotary valve which can achieve a good sealing performance over a long period of time with a simple sealing structure by solving the above-mentioned problems.

[0006]

The gist of the present invention is that a rotary shaft of a valve element rotates eccentrically from the center of curvature of a seal surface of a valve element abutting on a seat ring mounted in a valve box. An eccentric rotary valve in which the sealing surface of the valve body is in close contact with the seat ring and the sealing surface of the valve body rotates so as to be separated from the seat ring when the valve is opened. At least a portion of the surface of the rubber elastic body which is in contact with the fluid is covered with a PTFE sheet, and a lip portion is provided on the inner peripheral surface held by the valve box so as to protrude in a ring shape, and is sealed in the valve box. An eccentric rotary valve held by a seat ring holding member. In the above, the rubber elastic body is reinforced with a metal core bar, and the surface of the rubber elastic body is covered with a PTFE sheet. In the above, the thickness of the PTFE sheet is about 0.1 mm to 1 mm.

Further, the rotating shaft of the valve element rotates eccentrically from the center of curvature of the sealing surface of the valve element which comes into contact with the seat ring mounted in the valve box. Eccentric rotary valve that rotates in such a manner that the sealing surface of the valve body separates from the seat ring when the valve is opened,
The seat ring is provided with polytetrafluoroethylene, and the inner peripheral surface is held by a seat ring holding member hermetically mounted in a valve box. An annular ring is formed on one of the seat ring holding member and the rear surface of the seat ring. An eccentric rotary valve characterized in that a concave groove is formed and a rubber ring is mounted in the annular concave groove.

[0008]

The present invention has the above-mentioned structure, and even if a large contact pressure is applied to the seat ring due to the rotational force of the eccentric rotary valve body, the elastic force of the rubber elastic body inside the seat ring is used.
The rubber ring attached to the back of the seat ring allows
An elastic force acts on the TFE seat ring, and the contact surface pressure of the seat ring received by the rotational force of the valve body is absorbed by the elastic force of the rubber elastic body and the rubber ring. Therefore, creep does not occur in the PTFE seat ring and the PTFE seat,
Good sealing performance is obtained by contacting the valve body with an appropriate sealing surface pressure.

In each case, since the outer surface of the seat ring which is in contact with the fluid is made of PTFE, the rubber elastic body is also shielded from the fluid in the piping and the atmosphere, so that the rubber is not deteriorated.
By reinforcing the rubber elastic body with a metal core, the shape of the seat ring is stabilized, and the seat ring can be stably mounted and fixed in the valve box. In addition, the outer surface of the seat ring which comes into contact with the fluid in the valve box is a PTFE seat ring and a sheet. PTFE has excellent chemical resistance, and is used in various corrosive fluid pipes. No long-term sealing performance. Further, PTFE has a small frictional resistance with the valve body, a small rotating torque of the eccentric rotary valve body, and has a good opening / closing performance for rotating the valve body.

The rubber ring mounted on the back of the PTFE seat ring is mounted in an annular groove formed in the seat ring or the seat ring holding member, and the rotation of the valve body is stronger than the normal closed position. , The rubber ring in the groove is not excessively compressed, so that the contact surface pressure between the seat ring and the valve body is properly maintained and a good sealing action is performed. In addition, a seal on the back of the seat ring is obtained at the same time.
Therefore, unlike the conventional eccentric rotary valve, there is no need to provide a sheet member or a disc spring that slides in the valve box, and there is no problem of creep, and excellent sealing properties can be obtained over a long period of time.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 5 are views for explaining an embodiment of the present invention, and FIGS. 1 and 2 are views showing the structure of an eccentric rotary valve. In the figure, a valve body 20 has a partially spherical sealing surface 22 on the periphery of a valve plate 21, and has an upper arm 23 and a lower arm 25 formed on the upper and lower portions of the back surface of the valve plate 21. The lower arm 25 is connected to the valve box 10 with the support pin 27.
The valve body 20 is rotated by being pivotally supported at the lower portion of the inner surface of the valve body, and is brought into contact with a seat ring 30 provided in the one-side flow path 11 of the valve box 10 to open and close the valve body 20. As shown in FIG. 2, the rotation center S of the valve body 20 is decentered from the center of curvature O of the valve body sealing surface 22 in the closed state by ΔY in a direction orthogonal to the flow path axis X direction. For this reason, the valve body 20 contacts the seat ring 30 only after the valve body 20 is rotated near the fully closed position, and further rotates in the fully closed direction to increase the contact surface pressure with the seat ring 30 so that the valve can be completely closed. Has become. Seat ring 3
Numeral 0 is fixed to an inner surface of the valve box by being held by an insert 12 whose inner peripheral surface is hermetically screwed to the inner surface of the valve box flow path 11.

FIGS. 3 and 4 are sectional views showing the seat ring 30. FIG. The seat ring 31 in FIG. 3 includes a rubber elastic body 33 fixed to the inner surface of an angled core bar 32 made of stainless steel, and a PTFE sheet 34 bonded to this surface with a special adhesive. The thickness of the sheet 34 is 0.5 m
m, the rubber elastic body 33 and the surface of the metal core 32 are adhered and coated while applying heat. A lip portion 39 is provided on the inner peripheral surface so as to protrude in a ring shape.
When held inside, the sealing performance with the valve box is ensured by the compressive force of this portion.

FIG. 4 shows another seat ring 35. In this embodiment, a stainless steel cored bar 36 is molded into a rubber elastic body 37 and the outer surface thereof is covered with a PTFE sheet 38. The seat rings 31 and 35 shown in FIGS.
The portions of the valve box that come into contact with the fluid are also covered with sheets 34 and 38, and the cores 32 and 36 and the elastic rubber members 33 and 37 are held by the insert 12 in the valve box 10 so as not to come into contact with the fluid. At this time, the lip portion 39 on the inner peripheral surface of the seat ring 30 is compressed to reliably seal with the insert 12, and the outer surface covered with the PTFE sheets 34, 38 is covered with the inner surface of the valve box 10 and the insert 12 And the cores 32 and 36 and the rubber elastic bodies 33 and 37 do not come into contact with the fluid.

FIG. 5 is a partial sectional view of a seat ring mounting portion showing another embodiment of the eccentric rotary valve of the present invention. The seat ring 40 of this embodiment is made of a single piece of PTFE, the inner surface of which is supported by the insert 12, and is held slidably back and forth on the inner surface of the valve box 10. An annular groove 41 is provided on the back surface of the seat ring 40, and a rubber ring 42 is attached to the annular groove 41. The groove depth of the annular groove 41 is slightly smaller than the outer diameter of the rubber ring 42, and as shown in FIG.
When the seat ring 40 is closed and rotated, the seat ring 40 is pressed toward the flow path 11, so that the rubber ring 42 is compressed and abuts against the end side surface of the insert 12. While the rubber ring 42 is being compressed, the seat ring 40 is pressed against the valve body 20 with an appropriate sealing surface pressure by the repulsive force of the rubber ring 42, so that a good sealing action can be obtained.

As shown in FIG. 5, the seat ring 3 is normally attached to the side surface of the end of the insert 12 at the normal closing rotation position of the valve body 20.
9, the rubber ring 42 is confined in the annular groove 41, and the rubber ring 42
Does not protrude around the seat ring 40. When the valve element 20 is opened and rotated, the seat ring 40 slides toward the center of the valve box by the repulsive force of the rubber ring 42. Therefore, even when the valve body 20 is strongly rotated to the closing side, the rubber ring 42 and the seat ring 40 are prevented from being excessively compressed, and a sealing action is performed with an appropriate sealing surface pressure with the valve body 20. be able to. still,
The annular groove 41 may be provided on a side surface of the end of the insert 12 and a rubber ring 42 may be mounted. As described above, the eccentric rotary valve using the seat rings 30 and 40 according to the present embodiment has a low frictional resistance because the PTFE sheet on the surface comes into contact with the valve body, and furthermore, the rubber ring 40 and the rubber elastic bodies 33 and 37.
Because of its excellent creep characteristics, it is not necessary to use a complicated sheet structure as in the past, and it has excellent chemical resistance,
It is an eccentric rotary valve capable of obtaining good sealing properties over a long period of time.

[0016]

As described above, the eccentric rotary valve of the present invention has a small frictional resistance with the valve body and is excellent in opening and closing operability of the valve.
In addition, the eccentric rotary valve maintains good sealing performance for a long time because of its good creep characteristics, is easy to manufacture without increasing the number of parts, and has excellent sealing durability.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an eccentric rotary valve according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating rotation of a valve body of the eccentric rotary valve of the present invention.

FIG. 3 is a view showing a seat ring 31 of the eccentric rotary valve of the present invention.

FIG. 4 is a sectional view showing a seat ring 35 according to another embodiment of the present invention.

FIG. 5 is a view showing a seat ring mounting portion of another embodiment of the eccentric rotary valve of the present invention.

FIG. 6 is a longitudinal sectional view illustrating a conventional eccentric rotary valve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Valve box 20 Valve body 12 Insert 23 Upper arm 25 Lower arm 27 Support pin 30, 31, 35, 40 Seat ring 32, 36 Core bar 33, 37 Rubber elastic body 34, 38 PTFE seat 39 Lip of inner peripheral surface of seat ring Part 41 annular concave groove 42 rubber ring

Claims (3)

[Claims] A rotating shaft of the valve body which is eccentrically rotated from a center of curvature of a sealing surface of a valve body which comes into contact with a seat ring mounted in a valve box, and which seals the valve body when the valve is closed; Eccentric rotary valve that rotates so that the sealing surface of the valve body separates from the seat ring when the valve is opened, wherein the seat ring is provided with a rubber elastic body at the center and the surface of the rubber elastic body At least a portion that comes into contact with the fluid is covered with a polytetrafluoroethylene sheet, and a lip portion that protrudes annularly on the inner peripheral surface is provided, and is held by a seat ring holding member hermetically mounted in the valve box. Core rotary valve. 2. The eccentric rotary valve according to claim 1, wherein the rubber elastic body of the seat ring is reinforced by a metal core. 3. The valve body rotating shaft rotates eccentrically from the center of curvature of a valve body sealing surface that comes into contact with a seat ring mounted in a valve box, and when the valve is closed, the valve body sealing surface becomes the seat ring. And an eccentric rotary valve that rotates so that the sealing surface of the valve body separates from the seat ring when the valve is opened, wherein the seat ring is provided with polytetrafluoroethylene and the inner peripheral surface is provided in the valve box. It is held by a seat ring holding member that is hermetically mounted, an annular groove is formed in one of the seat ring holding member and the back surface of the seat ring, and a rubber ring is mounted in the annular groove. Eccentric rotary valve.