JPH062775A - Diaphragm valve - Google Patents

Abstract

PURPOSE:To obtain an exceedingly compact diaphragm valve having a structure for preventing the outside flow-out of fluid even if a creep is generated on a sealed part because of the fluid pressure variation or temperature change for a long period. CONSTITUTION:As for a diaphragm valve which carries out communication and closure by an inlet flow passage 3, outlet flow passage 4, and a diaphragm 9, the diaphragm 9 has a structure having a disc part 10 at the center part and a membrane part 11 on the peripheral edge, and an annular fitted part 13 is formed on the peripheral edge part of the diaphragm 9, and fitted with the body 1, and futher the peripheral edge part 12 is nipped on the body 1 by a bonnette 16 through an elastic body 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diaphragm valve used for fluid transportation piping, and more particularly to a diaphragm valve having improved diaphragm sealing performance.

[0002]

2. Description of the Related Art In a conventional diaphragm valve,
As shown in FIG. 4, the locking projection 27 of the diaphragm is fitted into the fitting groove 28 of the valve body, and is clamped and fixed by the bonnet 29 to prevent fluid from leaking to the outside of the valve body.

[0003]

However, the sealing method has a problem that the sealing portion creeps and causes fluid leakage due to pressure fluctuations and temperature changes of the fluid over a long period of time. In particular, this tendency is remarkable in the fluororesins (PTFE, PFA, etc.) which are preferably used as the diaphragm material.

The present invention has been made to solve the above-mentioned problems of the prior art. The object of the present invention is to prevent liquid leakage even if the seal portion creeps due to pressure fluctuations or temperature changes of fluid. It is to provide a diaphragm valve having a structure that does not cause it.

[0005]

Means for Solving the Problems A diaphragm valve of the present invention for solving the above-mentioned problems is a diaphragm valve in which an inlet passage and an outlet passage are connected and closed by a diaphragm, and the diaphragm is provided at a central portion. The disk portion has a film portion on its peripheral edge, and an annular fitting portion is provided on the peripheral edge portion of the diaphragm to be fitted with the main body, and the peripheral edge portion is sandwiched by the main body by the bonnet via an elastic body. It is characterized by being present.

The material of the diaphragm valve of the present invention may be metal or plastic and is not particularly limited. Also, the material of the diaphragm is not particularly limited, but a fluororesin (eg PTFE, PFA, ECTFE, etc.)
Is particularly effective.

[0007]

When the diaphragm valve of the present invention having the above-mentioned structure is used, the fluid flows out from the inlet passage to the outlet passage through the space formed by the diaphragm and the main body. At this time, the fluid that has reached the space tries to flow out of the valve due to the action of the pressure, but since the peripheral portion of the diaphragm and the annular fitting portion are clamped and fixed by the main body and the bonnet, The outflow is stopped. Further, even if the peripheral portion or the corresponding portion of the main body creeps due to pressure fluctuations or temperature changes of the fluid over a long period of time, since the peripheral portion is backed up by the elastic body, the action of the elastic body causes the peripheral portion and the main body to move. The clearance with the corresponding part is not expanded, and the sealing effect can always be maintained.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a longitudinal cross-sectional view of a main part showing an open state of a plastic diaphragm valve which is an embodiment of the present invention. In the figure, reference numeral 1 is a stop valve type valve body (hereinafter referred to as a body), and an inlet passage 3 is formed by a partition wall 2 provided inside.
And the outlet flow path 4 are separated from each other, and the flow paths 3 and 4 are curved. 5 is a partition wall 2
Is an opening portion that is provided in the communication path and connects the inlet flow path 3 and the outlet flow path 4. Reference numeral 6 denotes an annular valve seat integrally provided around the partition wall 2, that is, the opening 5, and having a shape protruding upward. 7 is an annular groove provided in the upper part of the valve body 1,
Reference numeral 8 is a flat portion provided inside the annular groove 7 and is formed so that the area thereof is as small as possible. Further, the upper surface of the partition wall 2 from the flat portion 8 to the annular valve seat 6 is formed so as to be located below the flat portion 8.

A PTFE diaphragm 9 has a disk portion 10 at the center and a film portion 1 at the periphery of the disk portion 10.
1. A disk-shaped peripheral portion 12 is provided continuously to the film portion 11, and an annular fitting portion 13 having a rectangular cross section is integrally formed below the peripheral portion 12. Also, the disc section 1
0 has a threaded portion 14 protruding from the upper surface thereof.
Reference numeral 4 is screwed and fixed to the compressor 15. Further, the annular fitting portion 13 is fitted and fixed in the annular groove 7 of the main body,
The peripheral portion 12 is pressed from above by a cylindrical bonnet 16. Therefore, the peripheral portion 12 and the annular fitting portion 1
3 is sandwiched and fixed by the main body 1 and the bonnet 16. The lower surface 17 of the peripheral edge portion 12 is fixed to the flat portion 8 of the main body, and both side surfaces of the annular fitting portion 13 are fixed to the inner side surface of the annular groove 7, respectively.

The tubular bonnet 16 is provided at its center with an opening 18 slidably supporting the compressor 15. Further, an annular groove 19 is provided at the lower end of the bonnet 16 at a position corresponding to the flat portion 8.
An O-ring 20 is attached. Reference numeral 21 is a lid fixed to the bonnet, and an opening 2 provided in the center thereof.
2, the compressor 15 is slidably supported.

The operation of the diaphragm valve of this embodiment having the above structure is as follows. In FIG. 1, when a fluid is flown through the valve, the fluid passes through the inlet passage 3, the opening 5, the space 26 formed by the diaphragm 9 and the main body 1 and flows out to the outlet passage 4. The fluid that has reached the space 26 is affected by the pressure of the fluid, and the peripheral edge of the diaphragm 12
And, it tries to flow out of the valve through the clearance between the annular fitting portion 13 and the main body 1.

However, the peripheral edge portion 12 and the annular fitting portion 13 are connected to the annular groove 7 and the flat portion 8 of the main body 1 by the bonnet 16.
The fluid is prevented from flowing out of the valve because it is closely clamped and fixed to the valve. In addition, since the fluid pressure and the temperature fluctuate over a long period of time, the diaphragm peripheral portion 12
Even if the annular fitting portion 13 creeps or the flat portion 8 and the annular groove 7 of the main body are distorted, the peripheral edge portion 12 is constantly pressed by the flat portion 8 of the main body by the elastic action of the O-ring 20. The clearance between the lower surface 17 and the flat portion 8 does not increase, and the fluid is prevented from flowing out of the valve.

In order to make the elastic action of the O-ring 20 more effective, the sectional area of the flat portion 8, that is, the contact area between the lower surface 17 of the peripheral portion 12 of the diaphragm and the flat portion 8 is made as small as possible. It is necessary to form. At the same time, it is desirable that the O-ring 20 be configured so that the lower surface 17 is pressed against the flat portion 8 of the main body in a concentrated manner.

Further, as in this embodiment, the elastic member O
By using a ring, the diaphragm periphery 1
The purpose of intensively pressing 2 onto the flat portion 8 of the main body can be most effectively achieved, and at the same time, the creep of the elastic member itself can be suppressed to a minimum, so that there is a synergistic effect of enabling the elastic action for a long period of time. You can have it together. In that sense, it is much more effective to use an O-ring as the elastic member than to use a normally used sheet packing having a rectangular cross section. Further, in the case of this embodiment, the elastic action of the O-ring 20 does not act on the annular fitting portion 13 of the diaphragm and the annular groove 7 of the main body, but there is no particular need for it, and the above action alone is sufficient. You can overcome the problems.

Next, when the compressor 15 is moved downward by the driving force from the outside, the disk portion 10 of the diaphragm 9 is also moved downward in association with it and abuts against the main body annular valve seat 6 and is further pressed. Therefore, the flow path is now completely blocked and the valve is closed. Further, by the action opposite to this, when the compressor 15 is moved upward, the disk portion 10 is also moved upward and the valve is opened again. In this way, the valve is opened and closed.

Further, when the valve is opened and closed, a phenomenon occurs in which the disk portion 10 and the membrane portion 11 of the diaphragm 9 are pulled into the inside of the flat portion 8 of the body due to the action of fluid pressure. Since the annular fitting portion 13 is fitted and fixed in the annular groove 7 of the main body 1, such a phenomenon can be prevented.

FIG. 3 is an enlarged vertical cross-sectional view of an essential part showing another embodiment of the diaphragm valve of the present invention. The structure of the present embodiment is different from the first embodiment in that the main body annular groove 7
Annular projections 23, 24 having a triangular cross section on the bottom and the flat portion 8
Is provided one by one, and the sheet packing 25 is used as an elastic member instead of the O-ring,
The sheet packing 25 is configured so as to be able to press the upper surface of the peripheral edge portion 12 of the diaphragm over substantially the entire area, and other configurations are the same as those in the first embodiment.

According to the diaphragm valve of this embodiment constructed as described above, the lower surface 17 of the diaphragm peripheral portion 12 is pressed by the annular projection 24, and the lower end surface of the annular fitting portion 13 is pressed by the annular projection 23. Therefore, the outflow of fluid to the outside of the valve is stopped here. Further, since the contact area between the annular projections 23 and 24 and the diaphragm is extremely small, the sealing effect is extremely large.

Further, even if the diaphragm peripheral portion 12 and the annular fitting portion 13 or the flat portion 8 and the annular groove 7 of the main body 1 creep due to long-term fluctuations in the fluid pressure and temperature, the upper surface of the peripheral portion 12 remains. Seat packing 25
Since it is pressed against the annular protrusions 23 and 24 by this, the elastic action of the sheet packing 25 does not increase the clearance between the diaphragm 9 and the main body 1, and the sealing action is maintained.

In the case of the present embodiment, since the annular projections 23 and 24 are pressed against the diaphragm 9 at two places, even if the annular projection 24 or 25 is damaged for some reason, the second annular projection 25 or 24 will be damaged. Has a double sealing effect by preventing fluid from flowing out of the valve. The other operations are the same as those of the first embodiment of the present invention, and the description thereof will be omitted. Needless to say, the annular projections 23 and 24 described in the present embodiment bring about a greater effect when applied to the first embodiment of the present invention.

[0021]

By using the diaphragm valve of the present invention having the structure as described above, even if the seal portion creeps due to long-term fluctuations in fluid pressure and temperature, no liquid leaks to the outside of the valve. Fluid control with high safety becomes possible. Further, since this effect is achieved by an extremely simple structure, the valve device becomes compact, and at the same time, it is extremely inexpensive.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of an essential part of an embodiment of a diaphragm valve according to the present invention in an open state.

FIG. 2 is an enlarged vertical cross-sectional view of an essential part showing a seal portion of a diaphragm outer peripheral portion of the diaphragm valve in FIG.

FIG. 3 is an enlarged vertical sectional view of an essential part showing another embodiment of the diaphragm valve according to the present invention.

FIG. 4 is an enlarged vertical sectional view of a main part of a conventional diaphragm valve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Main body 2 ... Partition wall 3 ... Entrance flow path 4 ... Exit flow path 7 ... Annular groove 8 ... Flat part 9 ... Diaphragm 10 ... Disk part 11 ... Membrane part 12 ... Peripheral part 13 ... Annular fitting part 16 ... Bonnet 20 ... O-ring 23 ... Annular projection 24 ... Annular projection 25 ... Seat packing 26 ... Space 27 ... Locking projection 28 ... Fitting groove 29 ... Bonnet

Claims (2)

[Claims] 1. A diaphragm valve which connects and closes an inlet flow path and an outlet flow path with a diaphragm, wherein the diaphragm has a disk portion at a central portion and a membrane portion at a peripheral portion, and the peripheral portion of the diaphragm has a peripheral portion. A diaphragm valve, wherein an annular fitting portion is provided and fitted to a main body, and the peripheral edge portion is sandwiched by the main body by a bonnet via an elastic body. 2. The diaphragm valve according to claim 1, wherein the elastic body is an O-ring.