JPH10184947A - Diaphragm valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the service life of a diaphragm from being shortened when a user applies operating fluid pressure exceeding specified pressure to a piston. SOLUTION: A diaphragm valve is provided with a bonnet 3, a piston 8 fitted in a cylinder chamber 11 of the bonnet so as to be freely slid, a spindle 7 perforating the piston and to be raised and lowered by the piston, and a diaphragm 4 to be raised and lowered by the spindle, and the piston is operated by fluid pressure to open the valve. The piston is fitted between the upper limit part 7a and the lower limit part 7b provided on the spindle so as to be freely slid, and a spring 10 to be extended and contracted in the axial direction is provided between the piston and the lower limit part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a diaphragm valve,
In particular, the present invention relates to a diaphragm valve in which a piston is actuated by operating fluid pressure to close the valve.

[0002]

2. Description of the Related Art In a conventional diaphragm valve, a piston reciprocating in a cylinder chamber under operating fluid pressure, spring force or the like moves up and down a diaphragm made of an elastic material through a spindle fixed to the piston. Opens and closes the diaphragm valve. In particular, in a diaphragm valve in which a piston is actuated by operating fluid pressure to close the valve, a fluid such as compressed air adjusted to a specified pressure is sent to a cylinder chamber to depress the piston, thereby closing the diaphragm valve. .

[0003]

As described above, in a conventional diaphragm valve, an operating fluid such as compressed air adjusted to a specified pressure is sent into a cylinder chamber to push down a piston to close the diaphragm valve. In some cases, compressed air or the like having a pressure significantly higher than the specified pressure is supplied to the cylinder chamber to operate the diaphragm valve. In this case, there is a problem that the life of the diaphragm is shortened because the diaphragm impacts and seats on the sheet surface with a larger pressing force than usual.

The present invention has been made in order to solve such a problem. Even when a user sends compressed air or the like having a pressure exceeding a specified pressure into a cylinder chamber to operate a diaphragm valve, the life of the diaphragm is reduced. It is an object of the present invention to provide a diaphragm valve which does not shorten.

[0005]

In order to solve the above-mentioned problems, the present invention employs a bonnet, a piston slidably fitted in a cylinder chamber of the bonnet, and
A diaphragm valve that includes a spindle that penetrates the piston and is raised and lowered by the piston, and a diaphragm that is raised and lowered by the spindle, wherein the piston is actuated by operating fluid pressure to close the valve. And a spring means which is slidably fitted between the piston and the piston and extends and contracts in the axial direction between the piston and the lower limit. Preferably, a stopper for restricting the lowering limit of the piston is provided between the piston and the bonnet. For example, the spring means may be loosely fitted to the spindle, and the stopper may be loosely fitted to the spindle so as to surround the spring means.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the above-mentioned diaphragm valve, the diaphragm valve includes a bonnet, a piston slidably fitted in a cylinder chamber of the bonnet, a spindle which penetrates the piston and is raised and lowered by the piston, The piston is actuated by operating fluid pressure to close the valve, and the piston is slidably fitted between an upper limit and a lower limit provided on the spindle. And a spring means which expands and contracts in the axial direction. That is, when the diaphragm valve is opened without applying the fluid pressure to the piston to close the valve, the spring means extends to bring the piston into contact with the upper limit provided on the spindle. On the other hand, when fluid pressure for closing is applied to the piston, the diaphragm seats on the seat surface and the diaphragm valve closes, the spring means contracts axially between the piston and the lower limit, The piston to which the fluid pressure is applied is instantaneously slid toward the lower limit of the spindle to reduce the impact force applied when the diaphragm is seated on the seat surface. Accordingly, even when the user sends a fluid such as compressed air having a pressure exceeding the specified pressure into the cylinder chamber, the impact force applied when the diaphragm is seated on the seat surface is appropriately reduced.

[0007] Preferably, a stopper is provided between the piston and the bonnet for restricting the lowering limit of the piston. That is, since the stopper receives the piston at the lower limit position and prohibits the piston from lowering the spindle below the predetermined position, the spindle is prevented from excessively pressing the diaphragm against the seat surface. Thus, even when the user sends a fluid such as compressed air having a pressure exceeding the specified pressure into the cylinder chamber, the maximum pressing force or the maximum crushing width when the diaphragm seats on the seat surface can be regulated. Further, in this case, the spring means alleviates the collision of the stopper when the stopper operates, thereby preventing the abrasion, breakage and the like of the stopper. Further, the minimum pressure of the cylinder chamber when the stopper operates can be easily changed by appropriately adjusting the spring force of the spring means.

For example, a spring means is loosely fitted on a spindle,
The stopper may be loosely fitted to the spindle so as to surround the spring means. As a result, the stopper also serves as a spring chamber for accommodating the spring means, and makes the whole diaphragm valve compact.

[0009]

FIG. 1 shows a diaphragm valve according to the present invention.
This will be described in detail with reference to FIG. As shown in FIG. 1, a diaphragm 4 is sandwiched between a main body 1 forming a flow path 2 and a bonnet 3. Body 1 and bonnet 3
Are screwed by flange bolts and nuts (not shown). The diaphragm 4 is screwed to a compressor 5, and the compressor 5 is attached to a lower end of a spindle 7 via a hanger 6. The spindle 7 is slidably and axially slidable inside the bonnet 3. A spindle 7 penetrates the center of the piston 8, and the piston 8 is slidable in an airtight manner with respect to the spindle 7. The spindle 7 has an upper limit 7a with an upper step and a lower limit 7b with a lower step.
Are formed at the top and bottom, respectively, and the piston 8
And the lower limit part 7b.

A cylindrical stopper 9 is fixed to the lower surface of the piston 8. Bottom 9 of stopper 9 fixed to piston 8
a and the lower end 7b of the spindle 7
(Spring means) is interposed. The disc spring 10 is loosely fitted to the spindle 7, and the stopper 9 is loosely fitted to the spindle 7 so as to surround the disc spring 10. Thus, the stopper 9 is connected to the disc spring 1
By setting the spring chamber to zero, the attitude of the entire disc spring 10 in several stages can be maintained, and the entire diaphragm valve can be made compact. The upper bonnet 3 forming the cylinder chamber 11 is hermetically mounted on the upper portion of the lower bonnet 3 described above. The piston 8 is fitted in the cylinder chamber 11 so as to be slidable in an airtight manner in the axial direction. A valve opening coil spring 12 is interposed between the piston 8 and the bonnet 3. The cap 13 is hermetically attached to the upper wall opening of the bonnet 3.

Next, the operation of the diaphragm valve according to the present invention will be described. FIG. 1 shows a state when the diaphragm valve is opened. That is, when the diaphragm valve is opened, the compressed air for operating the piston 8 is not supplied to the cylinder chamber 11, and the piston 8 is moved to the upper limit portion 7 a provided on the spindle 7 by the spring force of the coil spring 12. By moving and abutting on this, the spindle 7 is raised. Then, the spindle 7 pulls up the central portion of the diaphragm 4 via the hanging member 6 and the compressor 5, and the diaphragm valve is opened. At this time, the disc spring 1
0 is the maximum length while the tip 9 of the stopper 9 is
A gap 14 is interposed between b and the stopper receiving portion 3a of the bonnet 3.

FIG. 2 shows a state when the diaphragm valve is closed. That is, when the diaphragm valve is closed, compressed air adjusted to the specified pressure (fluid pressure) P1 for operating the piston 8 is supplied to the cylinder chamber 11. The piston 8 receives the pressure P1 and lowers the spindle 7 via the disc spring 10 against the spring force of the coil spring 12. Then, the spindle 7 includes the hanging tool 6 and the compressor 5.
The central part of the diaphragm 4 is seated on the seat surface 1a of the main body 1, and the diaphragm valve is closed. Here, the disc spring 10 is extended to almost the maximum length when the specified pressure P1 is applied to the piston 8 in the same manner as when the valve is closed.
And descends integrally with the spindle 7 in a state of being almost in contact with the upper limit portion 7a provided in the spindle. However, when the diaphragm 4 seats on the seat surface 1a, the disc spring 10 contracts instantaneously,
The impact force received when the diaphragm 4 seats on the seat surface 1a is reduced. This prevents the life of the diaphragm 4 from being shortened. Here, in a state where the diaphragm 4 is properly seated on the seat surface 1a, the above-described gap 14 shown in FIG. 1 is still interposed.

Next, the specified pressure P is applied to the cylinder chamber 11.
When the compressed air is supplied to the working pressure (fluid pressure) P2 of the diaphragm 4 which exceeds 1 in the valve closing operation, when the diaphragm 4 seats on the seat surface 1a in the valve closing operation described above, the disc spring 10 Instantaneously retracts to reduce the impact force when the diaphragm 4 seats on the seat surface 1a, and the tip 9b of the stopper 9 contacts the stopper receiving portion 3a of the bonnet 3 as shown in FIG. 8 prevents the spindle 7 from lowering further. In this way, the stopper 9 regulates the lowering limit of the piston 8. As a result, even when compressed air having a pressure exceeding the service pressure P2 of the diaphragm 4 is supplied to the cylinder chamber 11, the pressing force for pressing the diaphragm 4 is regulated, and the diaphragm 4 exceeds a certain width and is applied to the seat surface 1a. Pressing is prevented. Thus, shortening of the life of the diaphragm 4 is more reliably prevented.

As described above, the width of the gap 14 between the distal end portion 9b of the stopper 9 and the stopper receiving portion 3a of the bonnet 3 and the spring force of the disc spring 10 shown in FIG. It is set based on the maximum pressing force or the maximum crushing width. Also, by appropriately adjusting the spring force of the disc spring 10, the minimum pressure of the compressed air when the stopper 9 operates can be easily changed without changing the width of the gap 14 shown in FIG. . On the other hand, since the spring force of the disc spring 10 increases in proportion to the contraction, the pushing force of the piston 8 as a whole decreases as the tip 9b of the stopper 9 approaches the stopper receiving portion 3a of the bonnet 3. , The collision between them is avoided,
Wear, breakage, and the like of the distal end portion 9b and the stopper receiving portion 3a are prevented. When the compressed air supplied to the cylinder chamber 11 is released, the piston 8 returns to the above-described valve-opened state again by the spring force of the coil spring 12 and the disc spring 10 as shown in FIG.

The spring means is not limited to the above-mentioned disc spring 10, but may be any kind of spring such as a coil spring or a gas spring. Further, the diaphragm valve of the present invention is not limited to the diaphragm valve opened by the above-described coil spring 12, but may be another kind of spring such as a gas spring, or a diaphragm valve opened by a fluid pressure or the like. Good. Further, the fluid for operating the piston 8 is not limited to the above-described compressed air, but may be another gas, a liquid such as hydraulic oil, or the like.

[0016]

As described in detail above, the diaphragm valve of the present invention has a bonnet material, a piston slidably fitted in a cylinder chamber of the bonnet, and a piston penetrating through the piston and raised and lowered by the piston. A spindle and a diaphragm that moves up and down by the spindle are provided, and the piston is actuated by fluid pressure to close the valve, and the piston is slidably fitted between an upper limit and a lower limit provided on the spindle. A spring means that expands and contracts in the axial direction between the lower limit portion and the lower limit portion is provided. Thereby, when fluid pressure is supplied to the piston, the diaphragm seats on the seat surface and the diaphragm valve closes, the spring means contracts in the axial direction between the piston and the lower limit, causing the piston on which fluid pressure is applied to move. By sliding in the direction of the lower limit of the spindle, the impact force applied when the diaphragm is seated on the seat surface is reduced, so even if the user sends a fluid such as compressed air exceeding the specified pressure into the cylinder chamber, the diaphragm will not move. This has an excellent effect that the shortening of the life is prevented.

[Brief description of the drawings]

FIG. 1 is a sectional front view showing a state when a diaphragm valve according to the present invention is opened.

FIG. 2 is a sectional front view showing a state when the diaphragm valve of FIG. 1 is closed.

[Explanation of symbols]

1 body, 1a seat surface, 2 flow path, 3 bonnet, 3a stopper receiving section, 4 diaphragm, 5 compressor, 6 hanging tool, 7 spindle, 7a upper limit section,
7b lower limit, 8 piston, 9 stopper, 9a bottom, 9b tip, 10 disc spring, 11 cylinder chamber,
12 coil spring, 13 cap, 14 gap

Claims (3)

[Claims] 1. A bonnet (3), a piston (8) slidably fitted in a cylinder chamber (11) of the bonnet, and a spindle (7) penetrating the piston and raised and lowered by the piston. And a diaphragm (4) lifted and lowered by the spindle, wherein the piston is actuated by fluid pressure to close the valve, wherein the piston has the upper end (7a) and the lower end (7b) provided on the spindle. ) And slidably fit between
A diaphragm valve comprising: a spring means (10) that expands and contracts in the axial direction between the piston and the lower limit. 2. The diaphragm valve according to claim 1, wherein a stopper (9) for restricting a lower limit of the piston is provided between the piston (8) and the bonnet (3). . 3. The spindle (7), wherein the spring means (10) is loosely fitted to the spindle (7), and the stopper (9) is loosely fitted to the spindle so as to surround the spring means. 2. The diaphragm valve according to 1.