JPH0425563Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a ball valve that opens and closes a fluid passage attached to a fluid piping of a fluid system to control the flow.

In a ball valve, a valve ball placed inside a valve casing is rotated by a valve shaft that passes through the valve casing in an airtight manner, and an annular valve seat placed on the inlet side, outlet side, or both of the inlet and outlet sides of the valve ball is rotated. They work together to open and close fluid passages.

The present invention particularly relates to a seal structure between an annular valve seat and a valve casing.

Conventional technology A conventional seal structure between an annular valve seat and a valve casing is such that an elastic member within the annular valve seat is biased toward the valve casing. and the valve casing. FIG. 1 is a sectional view of a conventional ball valve. The valve casing is formed by a body 1 and an end piece 3 which is threadedly connected to the body 1. Main body 1 and end member 3
An inlet 4, an outlet 5, and a valve chamber 6 are provided to form a fluid passage. A valve ball 7 is rotatably arranged in the valve chamber 6, a through hole 8 and a guide hole 9 are formed orthogonally to each other in the valve ball 7, and a parallel keyway 10 is provided above the guide hole 9. Annular valve seats 11 and 12 are arranged on the inlet 4 side and the outlet 5 side of the valve ball 7. FIG. 2 is an enlarged view of a conventional seal structure between an annular valve seat and a valve casing. 11 is an annular valve seat, 17 is an elastic member, and 7 is a valve ball. Belleville spring 1
5 connects the annular valve seat 11 to the valve ball 7 via the washer 13.
At the same time, the annular valve seat 11 is urged against the valve casing by the elastic member 17. The annular valve seat is usually made of synthetic resin or synthetic rubber.

Problems to be Solved by the Present Invention The structure described above has the problem of leakage within a short period of time after use. In other words, an annular valve seat made of synthetic resin or synthetic rubber is inferior in strength to one made of metal, so the reaction force of the biasing force of the elastic member that is constantly applied to the valve casing causes short-term damage to the center of the annular valve seat. This is because the valve casing is deformed between the valve casings and the elastic member cannot exert the desired urging force on the valve casing.

The technical problem of the invention is therefore to make it possible to maintain a good sealing effect between the annular valve seat and the valve casing over a long period of time.

Means for Solving the Problems The technical means of the present invention taken to solve the above problems is to arrange a valve ball having a through hole in a valve casing that forms a fluid passage, and rotate the valve ball. A valve shaft to be operated is provided to pass through the valve casing in an airtight manner, and an annular valve seat made of synthetic resin or synthetic rubber is placed in the fluid passageway to contact the valve ball and cooperate with the valve ball to open and close the fluid passageway. A recess is formed in the substantially annular center of the annular valve seat, and an elastic member such as a spring is arranged in the recess to bias the annular valve seat toward the center of the ring and toward the outer periphery of the ring. The outer peripheral side of the ring of an elastic member such as a spring is formed into a thin wall or a comb-teeth shape so that the elastic modulus of the elastic member is small on the outer peripheral side of the ring and large on the center side of the ring.

Effect The operation of the above technical means is as follows.

The elastic member within the annular valve seat is constantly subjected to force toward the center of the annular valve seat due to the reaction force of the biasing force against the valve casing, but the elastic modulus of the elastic member is larger toward the center of the ring than toward the outer circumference. Therefore, it does not deform toward the center of the ring. Therefore, the biasing force of the elastic member as originally designed is maintained between the annular valve seat and the valve casing for a long period of time, so that no leakage occurs.

Effect of invention The present invention produces the following specific effects.

By making the elastic modulus of the elastic member within the annular valve seat larger in the ring center direction than in the ring outer circumferential direction, the annular valve seat does not deform except for deformation due to sliding wear with the valve ball. The urging force applied to the valve casing by the elastic member within the valve seat does not change, and no leakage occurs for a long period of time.

Example An example showing a specific example of the above technical means will be described.

Embodiment 1: See FIGS. 3 and 4 The valve casing is formed by a body 1 and an end piece 3 which is threadedly connected to the body 1. Inlet 4 to main body 1 and end member 3
An outlet 5 and a valve chamber 6 are provided to form a fluid passage.

A valve ball 7 is rotatably arranged within the valve chamber 6.
A through hole 8 and a guide hole 9 are formed perpendicularly in the valve ball 7, and a parallel keyway 10 is provided above the guide hole 9.

An annular valve seat 1 is provided on the inlet 4 side and the outlet 5 side of the valve ball 7.
Place 1 and 12. Both valve seats 11 and 12 are made of synthetic resin such as Teflon, and are urged toward the valve ball 7 by disc springs 15 and 16 via washers 13 and 14. Concave portions are formed in the inlet-side side surface of the valve seat 11 and the outlet-side side surface of the washer 12, respectively, and variable-walled annular springs 32 and 33 having a U-shaped cross section and having a thin wall on the outer peripheral side of the annular valve seat and a thick wall on the center side of the ring are arranged. do. annular valve seat 11,
12 is not deformed toward the center of the ring by the variable thickness annular springs 32 and 33, and is urged against the wall surface of the end member 3 and the wall surface of the main body 1 with a constant force by the elastic force of the thin wall portion of the variable thickness annular springs 32 and 33. Ru.

A bearing hole 19 is formed in the main body 1, and a valve shaft 20 is rotatably arranged. The valve stem 20 passes through the guide hole 9 of the valve ball 7 and is inserted into the holding hole 21 of the main body 1 with a bush 22.
mating through. A packing 23 is interposed between the valve stem 20 and the bearing hole 19, a washer 24 is interposed between the valve stem 20 and the bearing hole 19, and a disc spring 25 is biased against a collar 26. An O-ring 27 is interposed on the outer periphery of the packing 23. A handle 28 is fixed to the upper end of the valve stem 20 with a bolt 29. The valve stem 20 is prevented from popping out by a snap spring 31 via a disc 30.

Example 2: See FIG. 5 This example is another example of Example 1, and is the third example.
Components corresponding to those in the figures and FIG. 4 are given the same reference numerals and detailed explanations will be omitted.

An annular valve seat 1 is provided on the inlet 4 side and the outlet 5 side of the valve ball 7.
Place 1 and 12. Both valve seats 11 and 12 are washers 1
Valve ball 7 with disc springs 15 and 16 via 3 and 14
bias in the direction. Recesses are formed in the inlet-side side surface of the valve seat 11 and the outlet-side side surface of the valve seat 12, and annular springs 32 and 33 having a U-shaped cross section and a comb-like shape on the outer peripheral side of the ring of the annular valve seat are arranged. 3 and 4 show that the annular valve seats 11 and 12 are biased with a constant force against the wall surface of the end member 3 and the wall surface of the main body 1 by the spring force of the comb-shaped annular springs 32 and 33 on the outer peripheral side of the ring. It is similar to that of .

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional ball valve. FIG. 2 is an enlarged view of the inlet side valve seat of a conventional example. FIG. 3 is a sectional view of the ball valve of the present invention. FIG. 4 is an enlarged view of the inlet side valve seat in the embodiment of the present invention. FIG. 5 is an enlarged view of the inlet side valve seat in another embodiment of the present invention. 1...Main body, 3...End member, 4...Inlet, 5...
... Outlet, 6 ... Valve chamber, 7 ... Valve ball, 8 ... Through hole, 11, 12 ... Annular valve seat, 15, 16 ...
Belleville spring, 17, 18... annular spring, 20... valve stem, 28... handle, 32, 33... annular spring with U-shaped cross section.

Claims (1)

[Scope of utility model registration request] A valve ball having a through hole is arranged in a valve casing forming a fluid passage, and a valve shaft for rotating the valve ball is provided to pass through the valve casing in an airtight manner,
An annular valve seat made of synthetic resin or synthetic rubber that comes into contact with the valve ball and cooperates with the valve ball to open and close the fluid passage is disposed within the fluid passage, and a recess is formed in the approximately annular center of the annular valve seat. in which an elastic member such as a spring is arranged in the concave portion to bias the annular valve seat toward the center of the ring and toward the outer circumference of the ring. A ball valve in which the elastic modulus of the elastic member is small on the outer peripheral side of the ring and large on the center side of the ring.