JPS58128581A - Automatic gas shut-off device - Google Patents

Abstract

PURPOSE:To prevent unburnt gas from discharging at the re-opening of flow passage by a structure wherein a valve closing by pressure drop and a throttle passage are provided. CONSTITUTION:Under the state that a shut-off valve shuts off flow passage, when a valve drive shaft 8 is pressed down to open a shut-off valve body 10 off a shut-off valve seat 6 under the condition that a shut-off valve is in a shut- off state, the pressure of gas in a valve seat port 5 becomes instantly equal to that in upstream side, while the pressure at the downstream of the valve 49 closing by pressure drop gradually rises according to the gas flowing in through the throttle passage 50. Provided that the total amount of leakage occured at the downstream of the automatic gas shut-off device does not exceed the amount of flow passing the throttle passage 50, the pressure in the supply pressure chamber 20 does not rise, resulting in keeping a diaphragm 19 at its extreme position and consequently in maintaining the valve 49 closing by pressure drop at its closed state. Accordingly, there is no fear of outflowing a large amount of unburnt gas at a breath to outside.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic gas shutoff device provided in the middle of a gas supply path.

As this type of device, for example, a prior art has been invented which shows an open state in FIG. 1 and a closed state in FIG. This is located in the middle of the gas supply path and communicates with the shutoff valve (to) which has a tendency to shut off due to the action of the shaft drive spring (to) and can be opened by external operation by pushing down the shutoff mark α4, and downstream of the shutoff valve. The supply pressure chamber (e) is separated from the supply pressure chamber members by a movable membrane α [phase], and the reference pressure chamber is normally connected to a constant pressure source, such as the atmosphere.
, the pressure regulating force applying means (to) which urges the movable membrane (to) in the direction of the supply pressure chamber member, and the movable membrane (to) act in conjunction with the movable membrane (to) to push the movable membrane (to) to the extreme limit in the direction of the reference pressure chamber (2). The shutoff prevention means prevents the shutoff valve (to) from changing from open to shut off when the shutoff valve is in a range including the position (FIG. 1) and its vicinity.

In this prior art, when reopening the road after the blockage, the blockage mark α is
When 4 is pressed down, a large amount of gas flows downstream in a short period of time via the shutoff valve (to). Even if there is a closed state aK6, if the leakage point in the piping leading to the leak remains undiscovered, there is a risk that a large amount of gas will be released to the outside at once.

The object of the present invention is to realize an automatic gas shutoff device that can minimize such danger.

The prior art K which illustrates the opening state and the blocking state in FIGS. 1 and 2, respectively, and the partial sudden change W which shows the opening state, the blocking state, and the state immediately after the opening operation, respectively, in FIGS. 3 to 3J.
The structure and operation of the present invention will be explained with reference to embodiments that include the following.

In Figures 3 to J, - indicates an upward shutoff valve seat provided downstream of the cutoff valve seat (6) and upstream of the supply piezoelectric ring, which is the part of the cutoff valve (toward), and - indicates the movable membrane α and the membrane. A shutoff valve body is fixed to the lower surface of a nut screwed into a membrane boss in order to fix the plate (2) and the shutoff valve seat (2), facing the shutoff valve seat (2). For K, the supply pressure chamber (1
) makes contact at the extreme position in the direction of direction and has a closing action. That is, the shutoff valve seat and the shutoff valve body constitute a shutoff valve when the pressure of the supply pressure chamber (1) decreases. The space of the valve seat hole (5) between the cutoff valve seat (6) and the closing valve seat is communicated with the supply pressure chamber (e) via the throttle passage.

With this configuration, in the shutoff state i1 of the shutoff valve shown in Figure 1, the shutoff mark α is pushed down as shown in Figure S, and the shutoff valve body α is pressed against the shutoff valve seat (6). When the opening operation is performed, the gas pressure in the valve seat hole (5) immediately becomes the same as that on the upstream side, but when the pressure decreases, the pressure downstream of the shutoff valve gradually increases due to the gas flowing through the throttle passage. rise to For example, if this inflow amount is reduced to a small flow of about 60 j/b, 1k
If the cross-sectional area of the throttle passage is determined so that the gas limit is 6.
The pressure in the supply pressure chamber (e) does not rise unless it exceeds 0 j/h, the movable membrane Q remains at the extreme position shown in FIG. 1, and the drop shutoff valve remains closed. Therefore, there is no risk of multiple sources of raw gas leaking outside at the same time. If you release your hand from the blocking sign in this state, the blocking sign 10iK shown in FIG. 1 returns.

When the leakage downstream is small, the pressure of the supply piezoelectric ring gradually rises, and as the movable membrane (2) rises against the pressure regulating spring, the drop shutoff valve opens, and the pressure immediately stops. It will be in an open state as shown in Figure 3.

Even if you release your hand from the block mark α◆ in this state, the open state shown in FIG. 3 is maintained.

According to the invention, the prior art has a 1 drop shutoff valve -
With just a few changes, such as the addition of a diaphragm passageway,
This is extremely effective because it eliminates the above-mentioned danger of releasing raw gas at the time of re-opening.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views showing the prior art device in an open state and a closed state, respectively; FIGS. FIGS. 2A and 2B are cross-sectional views illustrating an open state, a closed state, and a state immediately after an opening operation, respectively, of the flexible portion of the prior art device of FIGS. (to)...Shutoff valve 09...Movable membrane (E)...Supply pressure chamber (2)...Reference pressure chamber (2)...Pressure regulation energizing means--Block prevention means −・・・lower closing valve ring・・・throttle passage patent applicant Aichi Tokei Denki Co., Ltd. Tokyo Gas Co., Ltd.

Claims (1)

[Claims] There is a shutoff valve in the middle of the gas supply path that tends to shut off and can be opened by external operation, a supply pressure chamber that communicates downstream of the shutoff valve, and a movable membrane that separates the supply pressure chamber and normally provides a constant pressure source. a reference pressure chamber that communicates with the supply pressure chamber, a pressure regulation and urging means that urges the movable membrane in the direction of the supply pressure chamber, and a pressure adjustment means that operates in conjunction with the movable membrane so that it is at the extreme position in the direction of the reference pressure chamber and its vicinity. and a shutoff prevention means for preventing the shutoff valve from changing from opening to shutoff only when the shutoff valve is in a range between . and a drop shutoff valve that closes at the extreme position in the direction of the supply pressure chamber, and a space between the direct downstream of the cutoff valve and the low pressure shutoff valve is communicated with the supply chamber via a throttle passage. Gas automatic shutoff device.