JPS6143011Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an emergency gas shutoff valve for safe use of supply gas used in domestic, commercial, industrial, and other applications.

BACKGROUND ART Recently, gas consuming appliances have rapidly become popular, and accidents due to incomplete combustion, gas leaks, etc. are rapidly increasing. These accidents are often caused by flashbacks, extinctions, etc. that occur when the pressure of the supplied gas drops beyond an allowable range for some reason during use.

As a gas shutoff valve to prevent accidents caused by such a drop in gas pressure, for example,
As shown in US Pat. No. 5,592,545, it is known to employ a valve structure in which the force of a spring and the gas pressure acting on a diaphragm are counterbalanced, so that when the gas pressure drops, the force of the spring closes the valve and a locking means maintains the valve in the closed state.

However, with this structure in which the force of the spring and the gas pressure acting on the diaphragm are balanced, the force of the spring does not always act as a closing force that presses the valve body against the valve seat, and for example, when the gas pressure once drops, Later, when the predetermined pressure is restored again, the gas pressure pressing the diaphragm exceeds the pressing force of the spring, so the gas pressure acts as a valve opening force against the locking means, indicating that the locking means is inappropriate. In such cases, the valve body may become separated from the valve seat, resulting in gas leakage.

In order to solve this problem, the present inventors set the biasing force of the spring sufficiently large relative to the gas pressure acting on the diaphragm, and held the valve body in the open position against the biasing force of the spring. We focused on the fact that when the gas pressure drops below a certain value, the locking means is released and the valve is closed by the biasing force of a spring, and the valve is maintained in the closed state by the biasing force of the spring. did. According to this configuration, even if the gas pressure that has once decreased returns to a predetermined pressure, sufficient valve closing force can be obtained because the biasing force of the spring is large. However, when adopting such a configuration, the problem is to operate the locking means stably with a constant force, and we have conducted various experiments on the structure of the locking means for this purpose. As the locking means, it was confirmed that the structure in which a spherical engager disposed radially in a locking groove on an operating shaft equipped with a valve body is fitted and locked by a spring performs extremely stable operation. I was able to do that.

The present invention is based on such knowledge, and
A stable valve closing operation is performed when the gas pressure decreases to a certain value, and a reliable and stable valve closing operation is performed even if the gas pressure returns to the specified pressure once the gas pressure decreases. It is something.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings. Reference numeral 1 denotes a valve body, which has a gas inlet 2 and a gas outlet 3 on the left and right sides.
A valve seat 4 is formed between the gas outlet 3 and the gas outlet 3. The operating shaft 5, which is disposed vertically in the center of the valve body 1, is rotated upward in the valve closing direction by a spring 8 interposed between a spring seat 6 on the upper part of the shaft 5 and the upper cover 7 of the valve body 1. A valve element 9 is attached to the lower end of the actuating shaft 5 and abuts the valve seat 4 from below on the gas inlet 2 side.

Further, inside the valve body 1, the above-mentioned upper cover 7 is provided on the upper surface side of the main diaphragm 10 attached to the operating shaft 5.
An airtight pressure acting chamber 11 is provided between the main diaphragm 10 and the gas outlet 3, and the pressure acting chamber 11 and the gas outlet 3 are communicated with each other through a through hole 12 bored in the actuating shaft 5. The spherical engager 16 is supported in the holder 13 so as to be freely movable back and forth and is biased by the spring 14 in the direction of pressing against the actuating shaft 5 via the presser 15. A locking groove 17 is formed around the side surface of the actuating shaft 5, into which the engager 16 is fitted and locked when the actuating shaft 5 is in the depressed position (valve seat 4 open position). The locking force of the spherical engaging element 16 can be adjusted by moving the screw cap 18 back and forth to adjust the biasing force of the spring 14. This can be done through the adjustment hole 19 provided.

Further, the upper end of the actuating shaft 5 is made to protrude above the valve body 1, and a pressing portion 2 is provided at the upper end to push it down.
1, and a flexible cover 22 that encloses the operating shaft 5 is attached to the upper part of the valve body 1.

In the figure, 23 and 24 are diaphragms for maintaining airtightness between the gas outlet 3 and the pressure chamber 11 and other parts, and 25 is a screw cap with a breathing hole screwed onto the adjustment hole 19.

Next, the operation of the gas cutoff valve having the above configuration will be explained.

When the pressing part 21 is pressed from above the cover 22 to push down the operating shaft 5, the valve element 9 is separated from the valve seat 4, and the valve seat 4 opens, as shown by the chain line in FIG. The engaging element 16 is fitted and locked into the locking groove 17. Therefore, the gas flows from the gas inlet 2 to the gas outlet 3, and also passes through the through hole 12 to the pressure action chamber 1.
1. At this time, if the gas pressure is maintained within the allowable range, the gas pressure acting on the main diaphragm 10 within the pressure action chamber 11 and the locking force of the spherical engager 16 to the locking groove 17 will be synergistic. Due to this action, the actuating shaft 5 is held in the depressed position against the spring 8.

Next, when the gas pressure drops below a predetermined pressure,
Along with this, the gas pressure acting on the main diaphragm 10 in the pressure action chamber 11 decreases, and the sum of this pressure and the locking force of the engaging element 16 is increased by the spring 8.
When the biasing force becomes smaller than the biasing force of the spring 8, the operating shaft 5 moves upward due to the biasing force of the spring 8, and as a result, the valve body 9 comes into pressure contact with the valve seat 4, and the valve seat 4 is closed. At this time, the actuating shaft 5 rises due to the spherical engager 1
6 in the locking groove 17 does not proceed gradually as the gas pressure decreases, but occurs instantaneously when the biasing force of the spring 8 becomes greater than the locking force.

Even if the gas pressure rises again in the closed state of the valve seat 4, the actuating shaft 5 is held in the same position by the biasing force of the spring 8 and the gas pressure acting on the lower surface of the valve body 9. The valve seat 4 remains closed unless the operating shaft 5 is manually pushed down.
Further, unless the gas pressure is restored to the required pressure, the valve body 9 will not be held in the open position even if the operating shaft is manually pushed down.

As described above, according to the gas cutoff valve of the present invention, the valve seat can be reliably closed by the actuation of the actuation shaft in response to a drop in the pressure of the supplied gas, and the actuation shaft can close the valve seat in the open position of the valve seat. The spherical engager locks into the locking groove provided, so when the switch is activated, the switch is instantaneous when the gas pressure drops below a certain value, and even after the gas pressure returns, the spring does not release. The biasing force reliably maintains the valve closed state, and the spherical engager allows the valve to be stably closed when the gas pressure drops to a certain value.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a gas cutoff valve according to the present invention, and FIG. 2 is a cross-sectional view of the main part thereof. 1... Valve body, 2... Gas inlet, 3... Gas outlet, 4... Valve seat, 5... Operating shaft, 8... Spring, 9... Valve body, 10... Main diaphragm, 11
... Pressure action chamber, 12 ... Through hole, 14 ... Spring, 16 ... Spherical engagement element, 17 ... Locking groove.

Claims (1)

[Scope of utility model registration request] A vertical operating shaft biased in the valve closing direction by a spring is disposed in the center of the valve body having a gas inlet and a gas outlet, and a vertical operating shaft is disposed at the lower end of the operating shaft midway between the gas inlet and the gas outlet. a valve body that abuts the valve seat, and communicates the gas outlet with an airtight pressure chamber defined by a main diaphragm attached to the operating shaft through a through hole provided in the operating shaft;
Spherical engagers biased by a spring in the direction of pressure contact with the operating shaft are arranged radially within the valve body, and the engagers are arranged around the operating shaft at a position where the operating shaft opens the valve seat. A locking groove is provided around the circumference for fitting and locking, and when the gas pressure acting on the main diaphragm drops below a predetermined pressure, the sum of that force and the locking force of the engaging element moves the operating shaft in the valve closing direction. An emergency gas cutoff valve characterized in that the urging force of the spring is set to be smaller than the urging force of the spring.