JPH0546480B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a gas piping system.

[Prior art and its problems] The gas pipes connected to each home are branched from the gas main pipe on the upstream side.
In some cases, the piping is configured as shown in the figure.

That is, an overflow prevention valve 3 is disposed at the most upstream part of a branch pipe 2 branched from a main pipe 1, and on the downstream side of the overflow prevention valve 3, a meter cock 4, a governor 50, a gas meter 5, and an indoor The terminal gas tank 6 and the like located at the most downstream part are connected by piping in this order.

The overflow prevention valve 3 automatically shuts off the gas flow path and prevents the release of a large amount of gas in the event of accidental destruction of a person buried underground due to road construction, etc., or in the event of a fire, etc. in each home. This valve is provided as a safety measure to prevent excessive overflow, and for example, a structure as shown in FIG. 5 can be adopted as the overflow prevention valve.

That is, the overflow prevention valve 3 shown in the same figure has a cylindrical body 31
A spherical valve body 33 is loaded inside the valve body 3.
3 is connected to a fixing pin 35 by a coil spring 34. Further, a valve seat 32 is formed on the inner periphery of the downstream end of the cylindrical body 31, and the gas flow is configured to flow from the valve body 33 toward the valve seat 32.

When a large amount of gas is released from the terminal gas tanks 6 and 8 due to a fire outbreak, or when gas is released due to the underground pipe breaking,
The gas flow in the gas flow path increases, and as a result, the valve body 33 is pushed downstream against the coil spring 34 and fitted into the valve seat 32. That is, the gas supply to the downstream side is automatically cut off. This prevents secondary disasters such as explosions due to the release of a large amount of gas from the destroyed location or the release of raw gas into the fire area.

However, in the conventional gas piping system mentioned above,
Even if the damaged part of the piping system is repaired, there is a problem in that if the overflow prevention valve is returned to its initial state (reset), the governor 50 and gas meter 5 will be damaged.

That is, as a method of returning the overflow prevention valve 3 to its initial state, a method can be considered to bring the gas pressure in the gas flow path downstream of the overflow prevention valve 3 to a high pressure state. However, in the conventional gas piping system described above, This is because high pressure gas is supplied from the terminal gas tanks 6, 6, and in this case, high pressure is applied to the governor 50 and gas meter 5.

Then, to the governor 50 and gas meter 5,
If high pressure gas exceeding the allowable pressure is supplied, the governor 50 and gas meter 5 will be damaged.

[Technical Problem] The present invention provides an overflow prevention valve 3, which is activated by the pressure difference between the upstream and downstream channels, at the most upstream part of a branch pipe 2 branched from a common main pipe 1 to each household. In the gas piping system where the meter stock 4 and the gas meter 5 following it are piped, overflow prevention valve 3 is installed to prevent damage to the governor 50, gas meter 5, etc. even if the overflow prevention valve 3 is reset. The objective is to prevent high pressure from being applied to a gas meter 5, etc. when resetting a prevention valve.

[Technical Means] The technical means of the present invention for solving the above problems is to provide an opening/closing system for communicating with the outside in the gas flow path between the gas cutoff part of the meter cock 4 and the overflow prevention valve 3. This is because a possible branch flow path has been provided.

[Effect] The above technical means works as follows.

First, when the gas overflow occurs, the overflow prevention valve 3 operates in the same manner as the conventional valve described above to cut off the gas supply to the downstream side.

Next, when resetting the overflow prevention valve 3 to return the entire gas piping system to its initial state,
First, the meter tip 4 is closed to block the flow path downstream from the meter tip 4.

Next, a branch channel provided between the overflow prevention valve 3 and the meter stock 4 is opened, and high pressure gas is supplied from this section. Then, the high pressure gas is supplied between the overflow prevention valve 3 and the meter stock 4,
The pressure on the downstream side of the valve body 33 increases, thereby causing the valve body 33 to deviate toward the upstream side. That is, valve body 3
3 is opened and the overflow prevention valve 3 is in a reset state.

Since the meter stock 4 is in a closed state when the overflow prevention valve is reset, the high pressure supplied from the branch flow path is not transmitted to the governor 50, gas meter 5, etc.

Thereafter, when the gas supply from the branch channel is stopped and the opening of the branch channel is closed, the gas piping system as a whole returns to its initial state.

[effect] The present invention has the following unique effects.

Governor 50 when resetting the overflow prevention valve.
Since high pressure is not applied to the gas burner 5 and the gas burner 5, there is no fear that the gas meter 5 etc. will be damaged when the overflow prevention valve is reset.

[Embodiment] The flow path configuration between the overflow prevention valve 3 and the gas cutoff portion of the meter cock 4 is configured to include a valve body that closes the downstream circuit only when high pressure gas is supplied from the branch flow path. .

According to this embodiment, when high-pressure gas is supplied from the branch flow path, the valve body closes and blocks the downstream flow path, so that pressure is not transmitted to the downstream side of the valve body.

Therefore, even if a considerably high pressure is supplied from the branch flow path in order to quickly reset the overflow prevention valve 3, the seal of the meter stock 4 will remain at the boundary between the closure of the meter stock 4 and the housing portion of the closure. Pressure that exceeds the capacity will not be transmitted, and there is no worry that the airtightness of the meter cock 4 will destroy it.

[Example] Next, the above-described example of the present invention will be described in detail with reference to the drawings.

As shown in FIG. 1, the gas piping system according to the embodiment of the present invention includes an overflow prevention valve 3 and a meter cock 4.
The structure is similar to the conventional one described above except that a branch pipe 7 is inserted into the gas flow path in between.

As shown in FIG. 2, the branch pipe 7 is formed from a T-shaped pipe, and has the side opening 72.
is configured to be connected to the overflow prevention valve 3 side by piping, and the downstream opening 73 opposite thereto is configured to be connected to the meter stock 4 side by piping. The remaining flow path is a branch flow path 71, the open end of which is covered by a cap nut 74.

Further, a valve body 76 is attached to the branch portion of the flow path in the branch pipe 7, and is lifted toward the branch flow path 71 side in a normal state by a locking spring 75.

Now, when resetting the overflow prevention valve 3 that has been activated, first close the meter cock 4 to prevent high pressure from being applied to the governor 50, gas meter 5, etc. when pressure is supplied to the gas flow path, which will be described later.

Next, the cap nut 7 is inserted from the tip of the branch flow path 71.
4, and a plug 8 at the tip of a high-pressure supply device (not shown) is attached to that part. Then, the valve body 78 is pushed down by the tip of the plug 8 and rotated downward to close the downstream opening 73.

Then, when high-pressure gas is supplied from the plug 8 in the installed state, the valve body 33 of the overflow prevention valve 3 mentioned above escapes from the valve seat 32 due to the pressure.
The overflow prevention valve 3 will be reset.

FIG. 3 shows a modification of the branch pipe 7, in which an elevating body 77 is slidably mounted inside the branch flow path 71, and the above-mentioned 77 is lifted upward by a coil spring 78. There is.

An L-shaped through hole 78 is provided in the elevating body 77.
is bored, and when the elevating body 77 is lowered downward against the through hole 78, the elevating body 7
7 closes the downstream opening 73, and the lower opening of the through hole 78 of the branch pipe 7 faces 72.

[Brief explanation of the drawing]

FIG. 1 is a gas circuit diagram of an embodiment of the present invention, FIG. 2 is a sectional view of branch pipe 7, and FIG. 3 is a plug 8 in branch pipe 7.
Fig. 4 is a cross-sectional view showing the state in which the branch pipe 7 is installed.
5 is a sectional view showing a modification of the overflow prevention valve 3.
A cross-sectional view of the installation part, FIG. 6 is an explanatory diagram of a conventional example, and in the figure, 2...branch piping, 3...overflow prevention valve, 4...
Meter tip, 5... Gas meter, 6... Terminal gas tip, 32... Valve seat, 33... Valve body.

Claims (1)

[Claims] 1. At the most upstream part of a branch pipe 2 branched from a common main pipe 1 to each home, there is an overflow prevention valve 3 which is activated by the pressure difference between the upstream and downstream passages, and a meter is installed downstream of the overflow prevention valve 3. In a gas piping system in which the gas meter 5, etc. connected to the gas meter 4 is connected, the gas flow path between the gas cutoff part of the meter gas meter 4 and the overflow prevention valve 3 can be opened and closed to communicate with the outside. Gas piping system with branch flow paths. 2 The flow path configuration between the overflow prevention valve 3 and the gas cutoff portion of the meter cock 4 is configured to include a valve body that closes the downstream circuit only when high pressure gas is supplied from the branch flow path. Gas piping system according to scope 1.