JPH0247812Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to an improvement of a two-seat valve that requires less operating force when shutting off.

[Conventional technology]

Conventionally, as shown in FIG. 2, this type of two-seat valve has first and second valve seats 4 on a path from an inflow path 2 into which fluid F flows in a valve housing 1 to an outflow path 3. 5, and each of the valve seats 4, 5 can be opened and closed simultaneously by first and second valve bodies 7, 8 attached to a plunger 6 that reciprocates in the vertical axial direction by an appropriate drive mechanism. In addition, inflow channel 2
The force acting on the plunger 6 is such that the pressure of the fluid F flowing into the plunger 6 can be applied to each of the valve bodies 7 and 8 from the upper side of the first valve seat 4 and the lower side of the second valve seat 5. Some valves are constructed so that the amount of operating force required to close both valve seats 4 and 5 can be reduced.

[Problem that the invention attempts to solve]

However, in the conventional structure described above, since the first and second valve bodies 7 and 8 that are brought into contact with the first and second valve seats 4 and 5 have an integral structure, both valve seats 4 and , 5 at the same time requires a high degree of dimensional accuracy for the valve body and valve seat, resulting in a problem that the valve seat's shutoff performance is likely to be unstable.

[Purpose of invention]

The present invention was developed in view of the above-mentioned problems, and aims to provide a double-seat valve that requires less operating force to close the valve seat and has good valve seat closing performance. It is.

[Means for solving problems]

In order to solve the above-mentioned problems, the double-seat valve of the present invention includes a first valve seat provided between an inflow passage and an outflow passage of the valve housing, and a first valve seat provided between the inflow passage and the outflow passage of the first valve seat. A second valve seat coaxially provided on the opposite side, and a pressure balance hole attached to the plunger and passing through the inner periphery of the second valve seat and facing the first valve seat in the axial direction. a first valve body in which is opened;
A second valve seat that is loosely fitted around the outer periphery of the first valve body, has its back surface airtightly and elastically supported by the rear end of the first valve body via a bellows, and faces the second valve seat. The valve body is configured to include a valve body.

[Effect]

That is, in the present invention, with the above-described configuration, fluid pressure is applied to both upper and lower surfaces of the first valve body in the closed state, so that the force applied to the plunger by the fluid pressure is applied to the pressure receiving area of the plunger. Since only force is required, the valve operating force required to close the valve seat is small, and the capacity of the valve drive unit can be reduced. In addition, since the bellows has a dimensional error absorbing function, the first and second valve bodies are in good contact with the first and second valve seats, respectively, and the back surface of the first valve body is connected to the rear surface of the first valve body through the pressure balance hole. Since the fluid pressure introduced to the side acts as a back pressure on the second valve body from the outer periphery of the bellows, the close contact force of the second valve body when the valve is closed is improved. Moreover, during the valve opening operation, when the first valve element separates from the first valve seat, the fluid pressure acts on the inner periphery of the bellows from the front of the second valve element, thereby reducing the back pressure. Since this problem is resolved, the second valve body can also quickly open the valve.

〔Example〕

The present invention will be explained below based on an embodiment shown in FIG.

Figure 1 is a schematic diagram showing the dual seat valve of the present invention.
In the figure, 11 is a valve housing. A first valve seat 14 is provided in the valve housing 11 on a path from an inflow path 12 into which fluid F flows to an outflow path 13.
A second valve seat 15 is provided coaxially with the first valve seat 14 on the opposite side of the inflow passage 12. A first valve body 17 and a second valve body are attached to a plunger 16 that reciprocates in the vertical axial direction by a drive mechanism.
The valve body 18 is arranged so as to be able to come into contact with the valve body 18. The first valve body 17 is attached to the lower end of the plunger 16, while the second valve body 18 is movably and loosely fitted around the outer circumference of the first valve body 17. A back surface 18a is airtightly connected to the rear end portion 17a of the first valve body 17, which passes through the inner periphery of the second valve seat 15, via a metal bellows 19. A balance hole 20 is formed in communication with the first valve body 17, and the balance hole 20
through which the pressure of the fluid F can act from both the upper and lower surfaces of the first valve body 17, thereby reducing the resistance caused by the fluid pressure against the valve operating force when closing the first valve seat 14, In the second valve body 18, fluid pressure acts as a back pressure on the second valve body 15 from the outer periphery of the bellows 19 through the balance hole 20 provided in the first valve body 17, and the pressure of the fluid acts as a back pressure on the second valve body 15. When the valve seat 15 is closed, the valve seat 15 is self-tightened by the pressure of the fluid and the spring load to be brought into pressure contact with the second valve seat 15. Further, according to the above configuration, when the first valve body 17 is separated from the first valve seat 14 during the valve opening operation, the fluid pressure acts on the front surface of the second valve body 18 and the inner periphery of the bellows 19. Since the above-mentioned back pressure is eliminated, the second valve body 18 can also quickly open the valve.

As is clear from the above description, the present invention has the first and second valve seats provided in the valve housing closed by the first and second valve bodies, and the second valve seat provided in the valve housing. The valve body is provided to be freely movable, and in the closed state, fluid pressure is applied to both the front and back sides of the first valve body, and the second valve body is self-closing by applying the fluid pressure and spring load to the second valve seat. Since the structure is configured to close the valve, when the valve is closed, the pressure of the first valve body is balanced and
Not only can sufficient contact force be applied to the valve seat of the bellows, but the pressure acting on the outer periphery of the bellows through the pressure balance hole acts as back pressure on the second valve body, so the contact force of the second valve body is also improved. Moreover, when the valve is opened, the back pressure is immediately relieved at the same time as the first valve element is opened, so the second valve element can quickly open the valve without adhering to the second valve seat. It has the following effects.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of essential parts showing an embodiment of a two-seat valve according to the present invention, and FIG. 2 is a schematic cross-sectional view of a conventional two-seat valve. 11... Valve housing, 12... Inflow path, 13
...Outflow path, 14...First valve seat, 15...Second
valve seat, 16... plunger, 17... first valve body, 18... second valve body, 19... bellows, 2
0...Balance hole, F...Fluid.

Claims (1)

[Claims for Utility Model Registration] (1) A first valve seat provided between an inflow path and an outflow path of the valve housing, and a coaxial valve located at a position opposite to the inflow path of the first valve seat. The second line provided on the line
a first valve body, which is attached to the plunger and has a pressure balance hole in the axial direction that extends through the inner periphery of the second valve seat and faces the first valve seat; The second valve body is loosely fitted around the outer periphery of the first valve body, and its back surface is airtightly and elastically supported by the rear end of the first valve body via a bellows.
A two-seat valve, comprising: a valve seat and a second valve body facing the valve seat. (2) The first and second valve bodies are airtightly connected by a sealing member having spring properties such as a bellows, and the sealing member applies a spring load to the second valve body. A two-seat valve as set forth in claim 1 of the utility model registration claim characterized by: