JPH0361773A - Diaphragm valve - Google Patents

Abstract

PURPOSE:To reduce the stress of a diaphragm and extend the life by providing multiple fixed receiving faces closely stuck with a back face not faced to the flow passage of the diaphragm when a valve is opened, and providing multiple movable receiving faces closely stuck with the back face of the diaphragm when the valve is closed radially alternately with fixed receiving faces. CONSTITUTION:When a valve rod 14 is moved upward and a valve is opened, movable receiving faces 29 are located above fixed receiving faces 24, and the upper face of a diaphragm 10 deformed in a turned-over dish shape is closely stuck to fixed receiving faces 24 at multiple fan-shaped portions at a uniform angular interval. No stress by the fluid pressure is applied to the diaphragm 10. The above stress occurs at noncontact portions, but the width of adjacent fixed receiving faces 24 is narrow, thus the stress is small, and the value of the total stress applied to the diaphragm deformed in a turned-over dish shape is small. When the valve is closed, the upper face of the diaphragm 10 with a flat shape is closely stuck to movable receiving faces 29, no stress is applied to the close contact portions like when the valve is opened, and the stress on the noncontact portions is suppressed small. The maximum value of the stress is small when the valve is opened and when it is closed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a diaphragm valve that can extend the useful life of the diaphragm by reducing the value of the maximum stress generated in the diaphragm that undergoes repeated deformation.

Problems to be Solved by the Prior Art and the Invention Generally, in a diaphragm valve, stress is generated in the diaphragm due to its deformation and stress due to fluid pressure acting on the pressure receiving surface, and the maximum value of the combined stress is The larger the diaphragm, the shorter the diaphragm's service life.For this reason, it was considered to form a receiving surface in the space separated from the flow path by the diaphragm, with which the back of the diaphragm approaches and comes into close contact when the valve is opened. However, such a diaphragm valve is
When the valve is open, stress due to fluid pressure is no longer generated on the diaphragm, but when the valve is closed, the back surface of the diaphragm is separated from the receiving surface, so stress due to fluid pressure is inevitably generated on the diaphragm, and the diaphragm However, a large maximum stress still occurs, and the service life of the diaphragm cannot be extended.

Means for Solving the Problems As a means for solving the above problems, the diaphragm valve of the present invention has a plurality of fixed receiving surfaces arranged radially so that the back surface of the diaphragm that does not face the flow path comes into close contact with the valve when the valve is opened. A plurality of movable receiving surfaces, which operate together with the valve body and bring the back surface of the diaphragm into close contact with the valve when the valve is closed, are arranged in a radial pattern alternating with the fixed receiving surfaces.

Functions and Effects of the Invention The present invention has the above configuration, and when the back surface of the diaphragm comes into close contact with a plurality of fixed receiving surfaces in its radial portion when the valve is opened, stress due to the action of fluid pressure is applied to the diaphragm in that contact portion. In areas where the back surface does not come into close contact with the fixed receiving surface, stress is generated on the diaphragm due to the action of fluid pressure, but the value of this stress can be reduced by narrowing the distance between adjacent fixed receiving surfaces. By minimizing the value of the stress generated in the diaphragm due to fluid pressure, the maximum stress value can be kept small, and even when the back of the diaphragm comes into close contact with the movable receiving surface when the valve is closed, the above-mentioned Similarly, the maximum stress value generated in the diaphragm can be suppressed to a small value, and according to the present invention, the maximum stress value generated in the diaphragm in both the valve open and closed states can be suppressed to a small value. Therefore, the useful life of the diaphragm can be maintained for a long time.

EXAMPLE Hereinafter, an example of the present invention will be described based on the accompanying drawings.

In the figure, l is a body consisting of a main body 1a and a cover 1b attached to the upper surface of the main body 1a, and an inflow passage 3 that communicates an inflow port 2 on the right side surface with an annular opening on the upper surface of the main body 1a. is formed, and an outflow path 6 is formed that communicates the outflow port 4 on the left side with a valve port 5 opening circularly in the center of the top surface, and an outflow path 6 is formed between the top surface of the main body 1a and the bottom surface of the cover 1b. , a stainless steel diaphragm lO having a circular shape concentric with the valve port 5 connects its periphery to the main body 1a and the cover ib.
The diaphragm 1O has a circular portion corresponding to the valve seat 11 protruding from the upper edge of the valve port 5, which is press-molded into a semi-cylindrical shape. A valve body 12 is formed by expanding the valve body 12 downward, and a cover lb is provided at the center of the upper surface of the diaphragm 10 so as to be movable up and down. The valve rod is fitted with an upward force! The lower end surface of the piston 4 is attached by brazing or the like, and when the piston 16 of the air cylinder 15 attached to the upper part of the cover ib is raised by supplying pilot air, the diaphragm valve of this structure The valve rod 14, whose upper end surface is in contact with the lower surface, rises inside the cover 1b under the force of the compression coil spring 3 for urging the valve to open, and transforms the diaphragm 10 into a sunken dish shape with its central portion raised. By doing so, the valve body 12 of the diaphragm 10 is separated from the valve seat 11 and opened, and the pilot air is released to open the piston 1.
6 is moved downward by the elastic expansion force of the compression coil spring 17 for biasing valve closing, the valve rod 14 is pushed down by the piston 16, and the diaphragm lO is deformed into a flat shape, so that the valve body 12 (F seat The valve is closed when it comes into contact with !l.

A circular device chamber 20 is formed above the diaphragm 10 and is concentric with the diaphragm 10, surrounded by the upper surface of the diaphragm 10 and four parts of the lower surface of the cover Ib.
Inside the hollow, a circular fixed support 21 with the lower end of the valve stem 4 passed through the center hole 22 is connected to the diaphragm 10 with its lower surface corresponding to the upper surface of the diaphragm 10 with a space between them. This fixed support 2 is fixed concentrically.
A plurality of fan-shaped fixing protrusions 23 are formed downward at equal angular intervals in the circumferential direction on the lower surface of I, and the lower surface of each fixed protrusion 23 has a lower plate when the valve is open. A fixed receiving surface 24 is formed that slopes downward from the center side toward the peripheral edge side so as to align with the upper surface of the diaphragm lO.

Similarly, in the device chamber 20, a movable support 25 having an annular shape concentric with the diaphragm IO is in a state where its semicylindrical bulged lower surface is fitted into the recess of the valve body 12 of the diaphragm 10. By being sandwiched from above by a collar 27 on the outer periphery of the valve rod 14, it is fitted onto the lower end of the valve rod I4 so as to move up and down integrally. A plurality of fan-shaped movable protrusions 28 are spaced at equal angular intervals in the direction and protrude radially while being fitted between adjacent fixed protrusions 23 and 23 of the fixed support 21 so as to be relatively free to move up and down. , a horizontal movable receiving surface 29 is formed on the lower surface of each movable protrusion 28 so as to align with the upper surface of the diaphragm 10, which has a flat shape in the valve closed state. , a raised position retracted above the fixed receiving surface 24 as the valve rod 14 moves up and down;
It is configured to move up and down between a lowered position in which it extends below the fixed receiving surface 24.

This embodiment has the above configuration, and when the valve is opened by the upward movement of the valve rod I4, the movable receiving surface 29 is retracted above the fixed receiving surface 24, so as shown in FIG. ,
The upper surface of the diaphragm IO, which has been deformed into a dish-shaped shape, is in close contact with the fixed receiving surface 24 at a plurality of fan-shaped portions spaced at equal angular intervals in the circumferential direction, and in these contact portions, the fluid pressure acting on the lower surface of the diaphragm IO is On the other hand, in other fan-shaped portions that are not in close contact with the fixed receiving surface 24, stress due to the action of fluid pressure is generated on the diaphragm 10.
Since the fan-shaped portion that does not come into close contact with the fixed receiving surface 24 has a narrow width in the circumferential direction, the value of stress caused by fluid pressure is extremely small. The maximum value of stress, which is the sum of stress caused by the action of fluid pressure, is kept small.

In addition, in the valve closed state, the top surface of the diaphragm 10, which has a flat shape, is connected to the fixed receiving surface 2, as shown in FIG.
4, the fan-shaped portion that is in close contact with the movable receiving surface 29 is in close contact with the diaphragm 10 against the fluid pressure that acts on the lower surface of the diaphragm 1o. No stress is generated, and only a very small stress is generated on the diaphragm 10 in the other fan-shaped portions that are not in close contact with the movable receiving surface 29, and even in this closed state, the stress generated on the diaphragm 10 is small. The maximum value is kept small.

As described above, since the maximum value of the stress generated in the diaphragm 10 is kept small in both the valve open state and the valve closed state, the useful life of the diaphragm 10 is maintained long.

In this embodiment, the valve body 12 is formed integrally with the diaphragm lO, but the present invention also applies to a diaphragm valve having a structure in which a valve body formed separately from the diaphragm is fixed to the lower surface of the diaphragm. It is something that can be applied.

[Brief explanation of drawings]

The accompanying drawings show one embodiment of the present invention, and FIG. 1 is a sectional view;
Fig. 2 is a partially enlarged sectional view of the valve in the open state, Fig. 3 is a partially enlarged sectional view of the valve in the closed state, and Fig. 4 is a partially cutaway perspective view of a component with a fixed receiving surface and a component with a movable receiving surface. be. Installation body Two-liquid inlet Two-liquid inlet Two-liquid outlet 5: Valve port: Outflow path lO: Diaphragm 2: Valve body 24: Fixed receiving surface 29: Movable receiving surface

Claims (1)

[Claims] In the body, a diaphragm is installed and partitioned to define a flow path that communicates the inlet and the outlet, and in the flow path,
In a diaphragm valve having a valve port that is opened and closed by a valve body provided at the center of the diaphragm moving toward and away from each other as the diaphragm deforms, A plurality of fixed receiving surfaces that come into close contact are arranged radially, and a plurality of movable receiving surfaces that operate together with the valve body and come into close contact with the back surface of the diaphragm when the valve is closed are arranged radially alternating with the fixed receiving surfaces. A diaphragm valve characterized by being provided with