JPH0343507B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an opening/closing part of a pneumatic or hydraulic valve, and more particularly to an improvement of a seal structure in which the opening/closing part is interposed with a sealing material.

[Conventional technology]

A conventional valve having this type of seal structure is shown in FIG. The figure shows the opening and closing parts of the valve in the open state, where 1 is the valve body, 2 is the valve seat forming surface, 3 is the valve seat formed of a sealing material, 4 is the valve closing spring, and 5 is the fluid inlet. , 6 is a fluid outlet. In this valve 7, the valve body 1 is normally pressed against the valve seat 3 by the pressing force of the spring 4, thereby closing the space between the inlet 5 and the outlet 6. When a valve-opening force larger than the valve-closing force of the spring 4 acts on the valve body 1, for example, the fluid pressure at the inlet 5 increases and overcomes the force of the spring 4, and the valve opens as shown in the figure. state, the inlet 5 and the outlet 6 communicate with each other, and the fluid flows out to the outlet 6. The valve seat 3 is formed of rubber into an annular shape and is accommodated in an annular groove 2a formed in the valve seat forming surface 2 so as to slightly protrude toward the valve body 1 side.

[Problem that the invention seeks to solve]

Generally, if rubber materials are left in close contact with copper or iron-based materials for a long period of time, the rubber materials contain plasticizers, anti-aging materials, wax-like substances, sulfur, etc. and iron, and both become physically and chemically fixed. If the adhesion area is large, the components of the rubber material contained in the area tend to gather around the adhesion part, so the larger the adhesion area, the stronger the tendency to stick.

For this reason, in the conventional valve, the valve body 1 is pressed toward the valve seat forming surface side with the spring force necessary to ensure sufficient sealing performance when the valve is closed, and the valve body 1 is pressed against the rubber valve seat 3. If the state of close contact is maintained for a long period of time, there is a problem that the valve body 1 and the valve seat 3 will stick together. This may cause the valve to not open when it is required to open, so depending on the purpose of the valve, for example, if it is normally closed and only opens in case of an abnormality or emergency, it is natural that the valve will not open for a long period of time. Since the valve is kept closed, there is a very high possibility that the valve will not open, and if the valve does not open, problems such as malfunction of the system in which the valve is installed will occur.

[Means for solving problems]

The technical problem of this invention is to prevent the sealing material and the valve seat from sticking even if the valve body and the valve seat made of the sealing material are in a closed state in close contact for a long period of time. .

The means of this invention to solve this technical problem are:
An annular gasket groove is provided along the edge of the valve hole on the valve seat forming surface where the valve hole formed in the main body opens, a rubber sheet is installed at the bottom of the groove, and a groove is placed on the rubber sheet in the gasket groove. A lip packing made of ethylene tetrafluoride having lip portions on the bottom side and the groove opening side and a back-up spring interposed between both lip portions is installed, and is pressed against the valve seat forming surface side. A rubber sheet is installed on the surface of the valve body that closes the valve hole facing the gasket.

[Effect]

Since the lip seal, that is, the valve seat in this invention is made of tetrafluoroethylene, it is difficult to adhere to rubber materials, and since it has a lip, only a small area of the tip of the lip covers the rubber of the valve body. Demonstrates sealing performance by contacting the sheet surface.
Therefore, even if the valve is kept closed for a long period of time, the seal and the rubber sheet of the valve body will not stick together.

〔Example〕

One embodiment is shown in FIGS. 1 and 2. In this embodiment, if the inside of the explosive fuel gas bypass pipe becomes lower than a predetermined temperature, for example, if something such as low-temperature liquefied natural gas leaks and the temperature in the vicinity becomes low, there is a risk of danger. This valve opens a compressed air circuit that is separate from the gas circuit and detects leaks of dangerous gas.

The overall structure of the valve 20 is as shown in FIG. 2, and is flange-connected to a hazardous gas pipe 21. In the figure, 22 is a valve body, 23 is a valve body, and 24 is a packing.

The valve body 22 has an inlet 3 connected to a compressed air pipe.
0, a valve 31 connected to the inlet 30, a valve seat forming surface 32 which is the open surface of the valve hole 31, a valve chamber 33, and an outlet 34 to which a detection tube is connected.

The valve body 23 has a flange-like portion 36 provided on the open side of a cylindrical portion 35 with one end closed, and a protrusion portion provided on the closed end side to serve as a spring receiver 37. The end face of the flange-shaped portion 36 of the valve body 23 faces the valve seat forming surface 32 and is supported by a valve body support hole 38 formed in the valve body 22 so as to be freely movable back and forth. It is pressed against the surface 32. The spring 39 has one end in contact with a spring cover 40 screwed to the valve body 22, and the other end is received by the spring receiver 37. This spring 39 is made of shape memory alloy.

As shown in an enlarged view in FIG. 1, the packing 24 has an annular packing groove 41 along the edge of the valve hole 31 on the valve seat forming surface 32 of the valve body 22, and a rubber sheet at the bottom of the groove 41. It is installed on top of the 42 installed. This gasket 24 is a lip gasket, and has lip portions 2 on the bottom side and the opening side of the groove 41, respectively.
4a, 24b, both lip portions 24
A gap is formed between a and 24b, and a backup spring 43 is interposed within the gap. The packing 24 is made of tetrafluoroethylene,
The back up spring is made of stainless steel. A rubber sheet 44 is also provided on the flange-shaped portion 36 of the valve body 23 facing the packing 24.

In this valve 20, when the temperature inside the dangerous gas bypass pipe is higher than a predetermined temperature, the valve body 23 is pressed by the reaction force of the spring 39 and comes into contact with the gasket 24 in the groove 41 of the rubber sheet 44. ing. When the temperature inside the hazardous gas bypass pipe falls below a predetermined temperature, the reaction force of the spring 39 decreases, and the compressed air pressure acting on the valve element 23 opens the valve, allowing compressed air to flow into the valve chamber 3.
3. The gas is sent to the detection tube through the outlet 34, thereby detecting that the hazardous gas has begun to leak.

In such a valve 20, if the temperature set by the spring 39 is the temperature for detecting danger, the valve 20 is closed without opening almost as a precaution. The valve state will continue for a long period of time. However, in the unlikely event that a dangerous temperature is reached, the valve can be reliably opened and detected.

In other words, since we use a packing with a lip made of tetrafluoroethylene with a back-up spring, it is harder and less deformable than conventional rubber ones, so it does not get stuck in the air outlet gap. This is because there is no sticking between the valve seat side and the valve body side, and the valve opening sensitivity is good. Of course, the sealing effect is also good because the rubber sheet is provided on both the bottom of the packing groove and the valve body side, and the lip portion is sandwiched between the rubber sheets, so that sealing on both sides of the packing is ensured. As for the durability of the sealing action, the seal is equipped with a back-up spring, so the tension of the lip is guaranteed semi-permanently.

〔Effect of the invention〕

According to this invention, even if the opening/closing part of the valve is kept in the closed state for a long period of time, it does not become stuck. Moreover, both the sealing action and the durability thereof are good. Therefore, high reliability can be obtained by using it as a part of an abnormality detection device or the like.

[Brief explanation of drawings]

Fig. 1 is an enlarged sectional view of the main parts of an embodiment of the present invention, Fig. 2 is a longitudinal sectional view showing the state in which the valve of the same embodiment is used, and Fig. 3 is a conventional valve using a sealing material in the opening/closing part. FIG. 20... Valve, 22... Valve body, 23... Valve body,
24...Packing, 24a, 24b...Lip portion, 30...Inlet, 31...Valve hole, 32...Valve seat forming surface, 34...Outlet, 39...Spring, 41...
Packing groove, 42, 44...Rubber sheet.

Claims (1)

[Claims] 1. Provide an annular gasket groove along the edge of the valve hole on the valve seat forming surface where the valve hole formed in the main body opens, install a rubber sheet at the bottom of the groove, and place a rubber sheet on the rubber sheet in the gasket groove. A lip packing made of ethylene tetrafluoride having lip portions on the groove bottom side and the groove opening side and a back-up spring interposed between both lip portions is installed, and is pressed against the valve seat forming surface side. A sealing structure for an opening/closing part of a valve, comprising a rubber sheet installed on a surface of a valve body facing the gasket that closes the valve hole.