JP2000035144A - Injection type seat structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To certainly seal fluid by raising contact surface pressure between a valve chest seat part and a valve element seat part and to remarkably reduce valve opening and closing operating torque. SOLUTION: An elastic rubber seat 21 and a backup ring 24 free to elastically press on a valve element seat 10 at the time of closing a ball type valve element 7 are provided on a ring sheet part 2 provided on a valve chest 4 on the upstream side of the ball type valve element 7 at least, and an air supply pipe 23 free to inject and extract compressed air is provided in a ring space 22 formed on the back of these elastic rubber seat 21 and backup ring 24.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ball valve, and more particularly, to opening and closing a flow passage by rotation of a ball-shaped valve element disposed in a valve box. And a ball valve configured to seal a fluid such as a gas between them.

[0002]

2. Description of the Related Art FIG. 2 is a half sectional vertical sectional view of an entire ball valve which has been generally used in the past.
(The downstream side is not shown, but is the same as the upstream side)
Valve box 4 fitted and held in an airtight manner via ring 3
And is arranged so as to be inserted through a stand 5 fixedly extended upward from the valve box 4 so as to be rotatable about an axis b perpendicular to the axis a of the internal flow path 1 of the valve box 4. The valve stem 6 has a cylindrical flow passage 7A, which is disposed at the center of the supported valve stem 6 in the direction of the axis a in the valve box 4 and is fixed to the lower end of the valve stem 6. Valve box 4 with rotating operation
Ball-shaped valve element 7 which rotates around the axis b so as to open and close the internal flow path 1 of the ball-shaped valve body, and radially opposite sides perpendicular to streamlines of the cylindrical flow passage 7A in the ball-shaped valve element When the ball-shaped valve element 7 is closed and fixedly supported by the opposed part via the mounting bolt 8 and the nut 9, the arc-shaped valve element seat part 10 (which contacts the annular seat part 2 on the valve box 4 side). Although the downstream side is not shown, it is the same as the upstream side).

At the upper end of the stand 5 is fixedly supported an operating device 11 interlocked with the upper end of the valve rod 6, and at the upstream and downstream valve box annular seats 2,
As shown in FIG. 3, grease is injected into the annular gap 13 between the outer peripheral inclined portion 10a of the valve body seat portion 10 and the inclined portion 2a of the annular seat portion 2 on the valve box 4 side which comes in contact with the valve when the valve is closed. A greasing passage 12 for sealing the fluid (gas) is formed. A greasing pipe 14 for supplying grease into the greasing passage 12 rises upward from the valve box 4, and its upper end is supported by a bracket 15 fixed to the stand 5. In FIG. 2, reference numeral 16 denotes a fluid (gas) discharge pipe, and 17 denotes a suspension ring.

In the conventional ball valve having the above structure, when the valve is closed, the valve body seat portion 10 is passed through the greasing pipe 14 and the greasing passage 12.
The fluid (gas) leakage is sealed by injecting grease into the annular gap 13 between the outer peripheral inclined portion 10a and the inclined portion 2a of the annular seat portion 2 on the valve box 4 side.

[0005]

However, in the above-described ball valve having the conventional grease injection type seal structure, when the valve is closed, the valve element 7 is displaced downstream from the valve element seat portion 10 on the upstream side. And the seal surface pressure between the outer peripheral inclined portion 10a and the inclined portion 2a of the annular seat portion 2 on the valve box 4 side decreases, and the fluid leaks to the downstream side,
There was a possibility that the predetermined sealing performance could not be secured.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is possible to reliably seal the valve when the valve is closed regardless of the magnitude of the fluid pressure and to reduce the valve opening and valve closing operation torque. It is intended to provide structure.

[0007]

According to the present invention, there is provided an injectable sheet structure according to the present invention.
A valve box having an annular seat portion on each of an upstream side and a downstream side of the internal flow path, a valve stem rotatably held around an axis orthogonal to an axis of the internal flow path of the valve box, and a valve; A ball-shaped valve element that is disposed in the box and fixed to one end of the valve stem, and that opens and closes an internal flow path of the valve box with the rotation of the valve stem;
A ball that is fixedly supported by the ball-shaped valve body and has a valve body seat portion that contacts the upstream annular seat portion and the downstream annular seat portion to seal fluid when the valve body is closed. In the valve, of the upstream and downstream valve box seats, at least the upstream valve box seat is provided with an elastic rubber sheet that can be elastically pressed against the valve body sheet when the valve is closed, An air supply pipe capable of injecting and extracting compressed air is provided in a back space of the air conditioner.

According to the above construction, when the valve is closed, the compressed air is injected into the back space of the elastic rubber sheet in the valve box sheet through the air supply pipe, so that the elastic rubber sheet is elastically pressed against the valve body sheet. As a result, a large surface pressure is generated between the two sheet portions, and the fluid can be reliably sealed. Here, the surface pressure can be arbitrarily adjusted by increasing or decreasing the compressed air pressure, and a predetermined sealing performance can be ensured regardless of the magnitude of the internal fluid pressure.

When the valve is opened from the closed state, and
When closing the valve from the open state, by extracting air from the back space of the elastic rubber sheet through an air supply pipe,
The surface pressure between the two seat portions can be reduced to zero or very small, and the valve opening and closing operation torque can be significantly reduced, and the damage due to the rubbing of the elastic rubber sheet can be suppressed. .

[0010] In particular, according to a second aspect of the present invention, a backup ring having a concave portion receiving compressed air pressure behind the elastic rubber sheet is fitted and held through a taper having the same contact gradient as the elastic rubber sheet. By employing this, it is possible to reliably generate a predetermined sheet surface pressure by pressing the front end portion of the elastic rubber sheet against the valve body sheet portion without deforming the elastic rubber sheet into distortion by compressed air pressure.

According to the third aspect of the present invention, by installing a pressure gauge upstream of the compressed air supply pipe, it is possible to easily check the sheet surface pressure and to always generate an appropriate surface pressure so as to improve the sealing performance. Stabilization can be achieved.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an enlarged vertical sectional view of a main part of a ball valve according to the present invention. Of the upstream and downstream annular seat portions 2 in the valve box 4 shown in FIG. It is configured as follows.

That is, the annular seat portion 2 which is fitted and held in an airtight manner with the valve box 4 via the O-ring 3 extends along the direction of the axis a of the internal flow path 1 of the valve box 4 and has a wide distal end and a downstream end. An annular passage 20 that opens toward the front is formed. The front end wide portion 20a in the annular passage 20 has the front end 2
1a is formed in a substantially circular shape elastically abutting on the outer peripheral inclined portion 10a of the valve body sheet portion 10, and an annular elastic rubber sheet 21 having a substantially cross-sectionally substantially square shape is fitted therein. Annular passage 20 behind rubber sheet 21
An annular space 22 is formed between the valve box 4 and the annular seat portion 2 so as to communicate with a narrow portion 20b of the air supply tube 23. An air supply pipe 23 through which compressed air can be injected and extracted from the annular space 22 is formed.
Is set up from the valve box 4.

Behind the elastic rubber sheet 21, a side receiving the compressed air pressure is formed in a concave shape, and a backup ring 24 having the same contact gradient as the elastic rubber sheet 21 is fitted and held on the elastic rubber sheet 21 side. ing. A pressure gauge (not shown) is provided upstream of the air supply pipe 23 so that the surface pressure of the elastic rubber sheet 21 and the valve body sheet portion 10 can be checked.

The entire structure of the ball valve is the same as that shown in FIG. 2 except for the configuration of the above-mentioned upstream annular seat portion 2, so that the overall structure is omitted. Further, the downstream annular seat portion 2 in the valve box 4 is similar to that shown in FIG.
A configuration in which grease is injected into the annular gap 13 between the outer peripheral inclined portion 10a of the valve seat 10 and the inclined portion 2a of the annular seat 2 on the valve box 4 side through the greasing pipe 14 and the greasing passage 12 when the valve is closed. However, the downstream annular seat portion 2 may have the same configuration as that of FIG.

In the ball valve having the above structure, the operating device 1
The ball-shaped valve element 7 is rotated by rotating the valve stem 6 through the valve 1, and the cylindrical flow path 7 A in the ball-shaped valve element 7 is fully closed so as to be orthogonal to the internal flow path 1 of the valve box 4. By injecting compressed air into the annular passage 20 through the air supply pipe 23 and the annular space 22 after setting the posture, the distal end portion 21a of the elastic rubber sheet 21 of the upstream valve box annular seat portion 2 is formed.
Can be elastically pressed against the outer peripheral inclined portion 10a of the valve body seat portion 10 to generate a large surface pressure between the two seat portions 2 and 10, thereby securely sealing the fluid (gas). Here, the surface pressure can be arbitrarily adjusted by increasing or decreasing the compressed air pressure while checking the pressure gauge, and a predetermined sealing performance can be secured regardless of the magnitude of the internal fluid pressure.

When the ball-shaped valve element 7 is rotated to open the valve from the valve-closed state, and when the ball-shaped valve element 7 is rotated to close the valve from the open state, the elastic rubber sheet 21 is used.
The air supply pipe 2 extends from the annular passage 20 and the annular space 22 at the back.
By extracting air to the outside through 3, the surface pressure between the two seat portions 2 and 10 can be reduced to zero or very small, and the valve opening and closing operation torque can be significantly reduced. In addition, the elastic rubber sheet 21 can be prevented from being damaged by being rubbed while strongly contacting the valve body sheet portion 10, and can be used for a long time.
Sealing performance can be reliably maintained.

[0018]

As described above, according to the present invention, when the valve is closed, compressed air having a pressure corresponding to the internal fluid pressure is injected into at least the space behind the elastic rubber sheet in the upstream valve box seat. , An elastic rubber sheet is elastically pressed against the valve body sheet portion to generate a large surface pressure between both seat portions,
The fluid can be reliably sealed regardless of the magnitude of the internal fluid pressure. Moreover, when opening the valve from the closed state,
And, when closing the valve from the open state, by extracting air from the back space of the elastic rubber sheet, it is possible to reduce the surface pressure between the two seat parts to zero or very small, so that the valve opening and It is possible to remarkably reduce the valve closing operation torque, suppress the damage due to the rubbing of the elastic rubber sheet, and maintain the excellent sealing performance even when used for a long time.

[Brief description of the drawings]

FIG. 1 is an enlarged vertical sectional view of a main part of a ball valve according to an embodiment of the present invention.

FIG. 2 is a half vertical sectional view of a general ball valve as a whole.

FIG. 3 is an enlarged vertical sectional view of a main part of a conventional ball valve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Internal flow path 2 Valve box side annular seat part 4 Valve box 6 Valve stem 7 Ball-shaped valve body 10 Valve body seat part 21 Elastic rubber sheet 22 Annular space (back space) 23 Air supply pipe 24 Backup ring a Flow path axis b Rotation axis

Claims (3)

[Claims] 1. A valve box having an annular seat portion on each of an upstream side and a downstream side of an internal flow path, and is rotatably held around an axis perpendicular to an axis of the internal flow path of the valve box. A valve stem, a ball-shaped valve body arranged in the valve box and fixed to one end of the valve stem, and a ball-shaped valve body that opens and closes an internal flow path of the valve box with rotation of the valve stem, and fixed to the ball-shaped valve body side A ball valve having a valve body seat portion that supports and seals fluid by contacting the upstream annular seat portion and the downstream annular seat portion when the valve body is supported and the valve body is closed. Of the downstream valve box seats, at least the upstream valve box seat is provided with an elastic rubber sheet that can be elastically pressed against the valve body sheet when the valve is closed, and compressed air is supplied to the space behind the elastic rubber sheet. Make sure that there is an air supply pipe that can be filled and withdrawn. Injection seat structure to butterflies. 2. A backup ring is provided behind the elastic rubber sheet. The backup ring has a concave portion for receiving compressed air pressure, and is fitted to the elastic rubber sheet through a taper having the same contact gradient as the elastic rubber sheet. The injectable sheet structure according to claim 1, which is held together. 3. The injection type seat structure according to claim 1, wherein a pressure gauge is attached to an upstream side of the compressed air supply pipe.