JPH102430A - Fluid pressure operated 3 port switching valve - Google Patents

Abstract

(57) [Problem] To provide a fluid-pressure operated three-port switching valve in which foreign matter is not mixed into a fluid and which is easy to assemble and maintain. A pressure fluid supply port (P) and an output port (A) are provided.
And a discharge port R, a valve body 2 having first and second valve seats 8a and 8b for connecting an output port to the supply port and the discharge port, and a first and second valve body integrally displaceably connected by fitting. It has first and second drive assemblies 3A and 3B in which pistons 11a and 11b and first and second diaphragms 6A and 6B are assembled, and these diaphragms are connected so as to be integrally displaceable by fitting both ends of a spindle 20. These members are integrally connected together with the cover 4 by connecting bolts 5 to form the three-port switching valve 1. Since the diaphragm and the piston, and the diaphragm and the spindle are connected by fitting, assembly and maintenance thereof are easy.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid-pressure operated three-port switching valve, and more particularly to a three-port switching valve suitable for foods and chemicals which do not want to contain foreign substances such as lubricants. Things.

[0002]

2. Description of the Related Art Some fluids flowing through a flow passage of a switching valve, such as foods and chemicals, do not want foreign matter such as grease or oil applied to a sliding seal portion to enter. Therefore, a switching valve that directly drives a valve element by a piston or a switching valve that switches a fluid flow by a valve element having a sliding seal portion cannot be used as a valve for food or chemicals. For this reason, when the fluid flowing through the flow path is a food or a chemical, a diaphragm-type switching valve that opens and closes a valve seat between the flow paths by the diaphragm is used. However, the diaphragm switching valve has a problem that the diaphragm is easily damaged when the pilot fluid pressure acting on the diaphragm is increased.

In order to solve this problem, a piston is provided on the pilot chamber side of the diaphragm so as to be integrally displaceable,
A fluid pressure operated two-port switching valve in which a diaphragm is displaced by a piston is proposed by Japanese Utility Model Publication No. 6-32528. This proposed two-port switching valve
Since the space between the flow path and the piston is air-tightly partitioned by the diaphragm, there is no danger of foreign substances such as lubricant being mixed into the fluid flowing through the flow path.Moreover, since the diaphragm is displaced by the piston, the pilot fluid pressure is high. Even in this case, there is an advantage that the diaphragm is not broken. However, if this switching valve is a three-port valve having a pressure fluid discharge port, it is necessary to provide a member for integrally displacing the two diaphragms for opening and closing the two valve seats. The assembly and maintenance of each member constituting the above are troublesome.

[0004]

The problem to be solved by the present invention is that foreign matter is not mixed into the fluid flowing through the flow path,
Another object of the present invention is to provide a fluid-pressure operated three-port switching valve that is easy to assemble and maintain.

[0005]

In order to solve the above-mentioned problems, a fluid pressure operated three-port switching valve according to the present invention comprises a supply port, an output port and a discharge port for a pressure fluid, and a supply port and a discharge port for an output port. First and second valve seats in a flow path communicating with the first and second diaphragms, first and second diaphragms for opening and closing these valve seats, and a diaphragm slidably provided on the opposite side of these diaphragms from the valve seats. It has first and second pistons that are integrally displaced, and a pilot chamber and a return chamber that are airtightly partitioned by these pistons, or two pilot chambers, and acts on the fluid pressure of a pilot fluid that is supplied to and discharged from the pilot chamber. The first and second pistons slide according to the magnitude of the force and the magnitude of the biasing force of the return spring contracted in the return chamber, or the magnitude of the acting force of the pilot fluid pressure supplied to and discharged from the two pilot chambers. In a fluid pressure operated three-port switching valve for opening and closing first and second valve seats by displacing an diaphragm, the three-port switching valve connects the three ports and the first and second valve seats facing each other. And a first and second drive assembly in which first and second pistons and first and second diaphragms connected to be integrally displaceable by fitting are assembled to first and second cylinder members, respectively. Prepared,
These drive assemblies are integrally mounted on the valve body so as to be opposed to the respective valve seats, and the first and second diaphragms are fitted at their opposite ends through the first and second valve seats at an intermediate portion. It is characterized in that it is connected so as to be integrally displaceable by the set spindle.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First and second pistons and first and second diaphragms connected so as to be integrally displaceable by fitting are formed as follows.
The first and second cylinders are attached to the first and second cylinder members, respectively.
A drive assembly is formed, and one end of a spindle is fitted to one of the diaphragms, and the spindle is made to face the corresponding valve seat through first and second valve seats formed on the valve body. When the other end of the spindle is fitted to the other diaphragm, and the first and second drive assemblies are integrally attached to the valve body, a fluid pressure operated three-port switching valve is formed. In this case, since the piston and the diaphragm, and the diaphragm and the spindle are all connected so as to be integrally displaceable by mutual fitting, assembling these components is easier than in the case where the components are attached by screws or other attachment members. In addition, there is no possibility that the fluid flowing through the flow path contacts the mounting member. Further, when the valve body and the first and second drive assemblies are separated from each other, a piston, a diaphragm, and the like can be taken out from each drive assembly, so that maintenance of these components is easy.

FIGS. 1 to 3 show a first embodiment of the present invention. This fluid-operated three-port switching valve 1 includes a valve body 2.
And first and second drive assemblies 3A and 3B, and cover 4
(See FIG. 3), these members are hermetically mounted by mounting bolts 5,... (See FIG. 3), and the first and second diaphragms 6A, 6B are provided between the valve body 2 and the drive assemblies 3A, 3B. The peripheral edges are each hermetically clamped.
In this case, it is needless to say that the mounting bolts 5,... Are located at places where they do not come into contact with the fluid flowing through the switching valve 1.

The valve body 2 has a supply port P and an output port A for the pressure fluid which are opened to face each other, and a discharge port R which is opened in a direction orthogonal to these ports.
First and second valve seats 8a and 8b are formed so as to face each other, and the first valve seat 8a in the flow path connecting the supply port P and the output port A is connected to the output port by the first diaphragm 6A. The second valve seat 8b in the flow path that connects the discharge port R with the valve A is opened and closed by the second diaphragm 6B. The first drive assembly 3A has a first cylinder member 9A having a bottomed square tubular shape and a first cylinder 10a formed therein, and the second drive assembly 3B has a square tubular shape having both ends opened and has an inside. A second cylinder member (9B) having a second cylinder (10b) is provided, and an opening of the cylinder member (9B) on the opposite side to the valve body (2) is closed by the cover (4). However, although not shown, the second cylinder member 9B may be formed into a bottomed square cylindrical shape like the first cylinder member 9A.

First and second pistons 11a and 11b slidably inserted into first and second cylinders 10a and 10b.
Has a protrusion 12 integrally formed on the diaphragm side,
This projection 12 is attached to the thick portion 6 at the center of the diaphragms 6A and 6B.
By being fitted into the mounting holes 13 formed in a, these diaphragms are assembled so as to be integrally displaceable. A sliding seal ring 14 for hermetically sealing between the cylinders 10a and 10b is fitted in grooves formed on the outer peripheral surfaces of the pistons 11a and 11b. The return chamber 16 is formed by the bottom wall of the first cylinder member 9A and the first cylinder 10a so that the return chamber 16 is formed by the cover 4 or the second cylinder member 9A.
A pilot chamber 17 is respectively formed by the bottom wall of B and the second cylinder 10b. In the return chamber 16, return springs 18, 18 arranged concentrically are contracted, and a pilot port 19 is opened in the cover 4. ing. When the second cylinder member 9B is formed into a square cylinder with a bottom, a pilot port is opened on the bottom wall of the second cylinder member 9B instead of the cover 4.

The diaphragms 6A and 6B have intermediate portions passing through the valve seats 8a and 8b of the valve body 2 and fitting portions 20 at both ends.
a, 20a are rigid spindles 20 fitted into mounting holes 21 provided in the thick portions 6a of these diaphragms, respectively.
Are connected so as to be integrally displaceable. Further, between the pistons and the diaphragms of the first and second cylinder members 9A and 9B, diaphragm supports 22 that abut against the diaphragms 6A and 6B to prevent excessive displacement are fitted respectively.

In the first embodiment, the first cylinder member 9A
Then, the return springs 18 and 18 and the first piston 11a are inserted, and the diaphragm receiver 22 is fitted thereto.
The first drive assembly 3A is formed by fitting the protrusion 12a of FIG. 1A and the mounting hole 13 of the first diaphragm 6A, and the second piston 11b is inserted into the second cylinder member 9B, and the diaphragm receiver 22 is fitted. When the projection 12 of the second piston 11b is fitted to the mounting hole 13 of the second diaphragm 6B, the second drive assembly 3B is formed. Next, the fitting portion 2 is inserted into one of the mounting holes 21 of these diaphragms.
0a is fitted to the spindle 20 through the valve seats 8a and 8b, and the other fitting portion 20a is fitted to the mounting hole 21 of the other diaphragm, and these drive assemblies 3A and 3B are covered by mounting bolts 5,. Valve body 2 with 4
, A three-port switching valve 1 is configured.

In this case, the pistons 11a and 11b and the diaphragms 6A and 6B, and the diaphragms 6A and 6B and the spindle 20 are connected so as to be integrally displaceable by fitting each other. Unlike the above, they are easy to assemble, and there is no possibility that the fluid flowing through the flow path contacts the mounting member. When the connection between the valve body 2 and the drive assemblies 3A, 3B and the cover 4 is separated, the diaphragm 6 connected by fitting is connected.
A and 6B and the pistons 11a and 11b, and the diaphragms 6A and 6B and the spindle 20 can be separated, so that maintenance is easy.

In the first embodiment, the pilot port 19
When the pilot fluid is supplied to the pilot chamber 17 from
Since the second diaphragm 6B closes the second valve seat 8b and the first diaphragm 6A connected by the rigid spindle 20 opens the first valve seat 8a against the urging force of the return springs 18,18, The pressure fluid in the supply port P is output from the output port A (see FIG. 1), and the diaphragm receiver 2
2 prevents excessive displacement of the first diaphragm 6A. When the pilot fluid in the pilot chamber 17 is discharged, the first diaphragm 6A closes the first valve seat 8a by the urging force of the return springs 18, 18, and the second diaphragm 6B opens the second valve seat 8b. The fluid in the port A is discharged outside from the discharge port R (see FIG. 2), and the diaphragm receiver 22 prevents the second diaphragm 6B from being excessively displaced.

In the first embodiment, the pistons 11a, 11a
b has a sliding seal ring 14, but the piston 1
Diaphragms 6A, 6B provided on the valve seat side of 1a, 11b
As a result, the lubricant applied to the sliding seal ring 14 for opening and closing the valve seats 8a and 8b does not come into contact with the fluid flowing through the flow path. Therefore, it is possible to provide a switching valve for a food or a chemical which is not likely to be mixed with a foreign substance such as a lubricant. Further, the diaphragm 6 displaced by the pistons 11a and 11b
Since A and 6B are connected by the rigid spindle 20, the pilot fluid pressure can be increased, and the diaphragms 6A and 6B can be reliably displaced integrally. Further, the pistons 11a, 11b and the diaphragms 6A, 6
Since the acting force of the pilot fluid pressure and the urging force of the return spring act on the fitting portion of the diaphragm 6A and 6B and the fitting portion of the diaphragm 6A and 6B and the spindle 20, the diaphragms 6A and 6B are long. Even if the opening and closing of the period valve seats 8a and 8b are repeated, these fitting portions do not come off.

FIG. 4 shows a second embodiment of the present invention.
The port switching valve 26 includes a first cylinder member 27A having the same shape as the second cylinder member 9B.
In addition, a pilot chamber 28 is provided instead of the return chamber. In the second embodiment, the diaphragm 6 is operated by the pilot fluid alternately supplied to and discharged from the pilot chambers 17 and 28.
A and 6B open and close valve seats 8a and 8b. Since other configurations and operations of the second embodiment are the same as those of the first embodiment, the same reference numerals are given to the same main parts in the drawings, and detailed description is omitted. Note that, similarly to the first cylinder member 9A of the first embodiment, these cylinder members 27A and 9B may be formed into a rectangular tube with a bottom, and the cover 4 may be omitted.

[0016]

The hydraulically actuated three-port valve of the present invention constitutes first and second drive assemblies by connecting the diaphragm and the piston and the diaphragm and the spindle so as to be integrally displaceable by mutual fitting. By connecting the diaphragms of these assemblies with a spindle and attaching them to the valve body, a three-port switching valve can be configured, so that assembly and maintenance are easier than those in which these are assembled with mounting members such as screws. In addition, there is no possibility that the fluid flowing through the flow path contacts the mounting member. In addition, since the two diaphragms are connected so as to be integrally displaceable by the spindle, these diaphragms can be reliably displaced. Further, since the forces in the fitting directions act on the fitting portions of the diaphragm and the piston and the fitting portions of the diaphragm and the spindle, the fitting portions do not come off even if the valve seat is repeatedly opened and closed for a long period of time.

[Brief description of the drawings]

FIG. 1 is a vertical sectional front view of a first embodiment.

FIG. 2 is a vertical sectional side view of the clan section.

FIG. 3 is a plan view of the same.

FIG. 4 is a vertical sectional front view of the second embodiment.

[Explanation of symbols]

 1, 26 3-port switching valve 2 Valve body 3A, 3B Drive assembly 6A, 6B Diaphragm 8a, 8b Valve seat 9A, 9B Cylinder member 11a, 11b Piston 16 Return chamber 17, 28 Pilot chamber 18 Return spring 20 Spindle P, A, R port

 ────────────────────────────────────────────────── ─── Continued from the front page (72) Inventor Taketaka Miwa 4-2-2 Kinudai, Yawahara-mura, Tsukuba-gun, Ibaraki Pref. SMC Corporation Tsukuba Technical Center

Claims (1)

[Claims] 1. A pressure fluid supply port, an output port, and a discharge port, first and second valve seats in a flow path connecting the output port to the supply port and the discharge port, and these valve seats are opened and closed. First and second diaphragms, first and second pistons slidably provided on opposite sides of the valve seats of these diaphragms and displaced integrally with the diaphragm, a pilot chamber air-tightly partitioned by these pistons, and A return chamber or two pilot chambers are provided, the magnitude of the acting force of the fluid pressure of the pilot fluid supplied to and discharged from the pilot chamber and the magnitude of the urging force of the return spring provided in the return chamber, or the supply to the two pilot chambers A fluid-pressure operated three-port switching valve that opens and closes first and second valve seats by displacing first and second diaphragms by first and second pistons that slide according to the magnitude of the acting force of the pilot fluid pressure to be discharged. To And a first and second pistons connected to the valve body having the three ports and the first and second valve seats facing each other so as to be integrally displaceable by fitting. First and second drive assemblies each having a second diaphragm attached to the first and second cylinder members, respectively, and these drive assemblies are integrally attached to the valve body so as to face the respective valve seats; A fluid-operated three-port, wherein the first and second diaphragms are integrally displaceably connected by spindles having an intermediate portion passing through the first and second valve seats and having both ends fitted to the diaphragms. Switching valve.