JPH0212360Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a self-holding on-off valve used in a compressor, etc., and more specifically, the invention is equipped with a safety device that operates when the temperature of the discharge air of the compressor reaches a predetermined temperature. Regarding self-holding shut-off valves.

Generally, in a rotary compressor, as shown in Fig. 1, air compressed by the action of compressor C is sent into receiver tank a via check valve e, and is sent into receiver tank a by the action of pressure holding valve d. However, in order to reduce the burden on starting the engine, the pressure in the receiver tank a is increased.
A self-retaining on-off valve b is attached to the pressure fluid circuit to release the pressure. As shown in FIG. 2, this on-off valve b has a space 2 formed inside a casing 1, and flow passages 5 and 6 communicating with the space 2, respectively.
is formed. Also, in this space 2, there is a flow path 5.
a valve body that is selectively positioned at an open position that opens the flow passage 6 until the air pressure in the flow passage 5 reaches a predetermined pressure; or a closed position that closes the flow passage 6 when the air pressure in the flow passage 5 reaches a predetermined pressure; 3, and a spring 4 that always biases the valve body 3 to the open position. Further, a rod body 3a is provided protruding from the valve body 3, and the casing 1
Its head protrudes outward from the hole 1a.

Since the on-off valve b is configured as described above,
When the engine is started, the valve body 3 is brought into pressure contact with the inner wall 1b of the casing by the pressure of the spring 4, and the passage from the flow passage 5 through the space 2 to the flow passage 6 is opened. Thereafter, the internal pressure of the receiver tank gradually increases due to the action of the compressor body, and when the air pressure of the compressed air flowing into the flow passage 5 reaches a predetermined pressure, the rod 3 protrudes from the casing 1.
When the head part a is lightly pressed, the valve body 3 can be moved to the right as shown by the imaginary line in the figure by overcoming the pressing force of the spring 4, and the valve body 3 can be pressed against the stepped portion 1c inside the casing. . Then, the path from the flow path 5 through the space 2 to the flow path 6 is blocked. As long as the pressure of the compressed air flowing in from the flow path 5 is equal to or higher than a predetermined pressure, the on-off valve can remain closed. On the other hand, when the compressor main body stops and the pressure of the compressed air flowing in from the flow path 5 becomes lower than the predetermined pressure, the valve body 3 moves to the left in the figure (indicated by the solid line) due to the pressure of the spring 4 and compresses the air. The air passage becomes open. Therefore, normally, the above configuration functions as an on-off valve, but the above on-off valve allows the compressor main body to continue operating even if the discharge air temperature of the compressor main body rises abnormally.
If the operation continues without noticing the abnormal rise in discharge air temperature, the compressor may seize up, resulting in a fire or other serious accident.

In order to eliminate the above drawbacks, an air temperature switch is attached to the air discharge part of the compressor, and when the discharge air temperature reaches a predetermined temperature, the air temperature switch is turned on, and when the switch is turned on, the engine injection In some compressors, it has been proposed and practiced to stop the engine by activating an electric magnet connected to the pump's stop lever. However, this device has the drawbacks of high component costs and a large amount of man-hours for installation.

The present invention was devised to solve the above-mentioned drawbacks, and its purpose is to provide a safety device that is inexpensive and easy to install, and that prevents accidents when the temperature of air discharged from a compressor rises abnormally. An object of the present invention is to provide a self-holding type on-off valve.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

In FIGS. 3 and 4, the same reference numerals as in FIG. 2 represent the same parts, and the parts with a dash symbol represent the same functions. Also, parts that overlap with the description of the conventional on-off valve will be omitted.

As shown in FIGS. 3 and 4, a second casing 7 is fixed to the side wall of the first casing 1' with a plurality of bolts 9, and a second valve body 8 is fitted into the space inside the second casing 7. has been done. A valve stem 8a is provided on the second valve body 8, protruding from the hole 1'a of the first casing 1', and facing the valve body 3 in the first casing. Further, the second casing 7 is connected to the check valve (the first
It is connected to a hole formed in the side wall 11 with reference numeral e) shown in the figure through a connecting pipe 12, and a metal fuse holder 10 is provided at the end on the check valve side, and a metal fuse 10a is built therein. metal fuse 10
a is designed to melt when it reaches a predetermined temperature, and when it melts, the connecting pipe 12 is opened, and the second casing 7 and the inside of the side wall 11 of the check valve e are communicated with each other.

Therefore, when the discharge air from the compressor main body reaches a predetermined temperature at which the metal fuse 10a melts for some reason, the metal fuse 10a melts and the compressed air in the discharge path flows through the connecting pipe 1, as shown in FIG.
2 and flows into the space 7a inside the second casing. The second valve body 8 is moved by the pressure of this inflowing compressed air, and the tip of the valve rod 8a protruding into the space 2 in the first casing presses the valve body 3, causing the valve body 3 to move. , the passage from the flow passage 5 through the space 2 to the flow passage 6 is opened. Then, the internal pressure of the receiver tank decreases, and the engine becomes idle, preventing an abnormal rise in the discharge air temperature and preventing a compressor accident.

As is clear from the above explanation, according to the present invention,
By attaching an inexpensive and easy-to-install safety device to a conventional self-holding on-off valve, it is possible to prevent accidents caused by an abnormal rise in the temperature of the air discharged from the compressor.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing an example of a conventional on-off valve attached to a compressor, Fig. 2 is a sectional view of the on-off valve, Fig. 3 is a sectional view of an embodiment of the present invention in a closed state, and Fig. 4 is a cross-sectional view of the open state. 1... Casing, 1'... First casing,
2... Space, 3... Valve body, 4... Spring, 5, 6...
...Flow path, 7...Second casing, 8...Second valve body, 10a...Metal fuse, 12...Connecting pipe.

Claims (1)

[Scope of utility model registration request] Provided in the air outflow side passage of the receiver tank,
A valve body is provided inside the casing, and this valve body is normally kept in the open position by being biased by a spring.
In the self-holding on-off valve in which the valve body is pushed to the closed position by the inflow of compressed air from the receiver tank, the casing includes a second valve.
a casing is fixed, a second valve body is provided within the second casing, a valve stem protruding from the tip thereof is made to protrude into the casing and face the valve body; A connecting pipe is connected to a check valve provided in the inflow side passage of the receiver tank, and the connecting pipe is provided with a metal fuse that melts and opens the connecting pipe when the compressed air reaches a predetermined temperature. A self-holding on-off valve equipped with a safety device.