JP4540317B2 - Air purge method for gas supply equipment - Google Patents

Description

  The present invention provides, for each of a plurality of dwelling units constituting a multi-story apartment house, a main pipe buried in the ground, a main pipe connected to the main pipe, a common stand pipe connected to the main pipe, and the common In a gas supply facility for supplying a gas mainly composed of natural gas from a vertical pipe through a branch pipe, after the pipe is cut upstream from the common vertical pipe, the pipe is cut downstream from the cut portion. The present invention relates to an air purging method for a gas supply facility that performs air purging for removing air mixed in a side pipe and replacing it with the gas.

  Conventionally, this type of air purging method involves only the gas meter part located on the uppermost stream side of the common standpipe after completion of construction, that is, the gas meter part installed for the dwelling unit on the first floor. A method has been proposed in which air purging is unnecessary in a gas meter portion installed in a dwelling unit on the second floor or higher by performing air purging (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 2002-364776

However, according to the method described in the above publication, air purging is performed only on the first-floor gas meter section regardless of the difference in piping of gas supply equipment to the housing complex, the construction status, and the type of gas to be supplied. To eliminate the need for air purging in the gas meter section on the second floor and above, and questions remain regarding its effectiveness.
In other words, gas supply facilities have various pipe configurations depending on the structure and location conditions of the housing complex.Therefore, even if it is replacement work for service pipes, existing pipes are always installed at the same location under the same conditions. The gas to be supplied is not limited to cutting, and there are many gases having different specific gravity against air, such as various city gases and propane gas.
Ignoring these differences, it is possible to purify air only in the gas meter part on the first floor and to avoid the need for air purging elsewhere, even if possible under certain conditions. It may not be possible to say that it is applicable.

  The present invention pays attention to such conventional problems, and its purpose is limited to the gas mainly composed of natural gas, but the minimum necessary air purge is performed regardless of other conditions. An object of the present invention is to provide an air purge method for a gas supply facility that only requires.

The first characteristic configuration of the present invention is that, for each of a plurality of dwelling units constituting a multi-story apartment house, a main pipe buried in the ground, a main pipe connected to the main pipe, and a common stand connected to the main pipe In a gas supply facility for supplying a gas mainly composed of natural gas via a branch pipe branched from the common stand pipe, after cutting the pipe upstream from the common stand pipe, An air purging method for a gas supply facility for performing air purging for removing air mixed in a pipe downstream from a cut portion of the pipe and replacing it with the gas, wherein the floor of the uppermost floor of the housing complex is 6.0 m. the has exceeded, as a reference point of the cut portion of the tube, the overall length of the downstream side of the shared stand pipe from the reference point as Lm, {2.5 + L × a height direction from the reference point (2.3 / 100 )} M or more of the common located on the downstream side Branch pipe from the pipe, the gas meter portion is attached to the branch pipe, or is only where implementing the air purge Oite indoor side distribution pipe connected to the downstream side of the branch pipe.

According to the first characteristic configuration of the present invention, in the gas supply facility for supplying a gas mainly composed of natural gas, the floor of the top floor is an apartment house that exceeds 6.0 m , and is upstream from the common standpipe. After the pipe cutting work is carried out in step 2, the pipe cutting point in the cutting work is used as a reference point, the total length of the common stand pipe downstream from the reference point is Lm, and the height from the reference point in the height direction {2. 5 + L × (2.3 / 100)} m or more The branch pipe from the common stand pipe located closest to the downstream side, the gas meter portion attached to the branch pipe , or the house connected to the downstream side of the branch pipe since only implement an air purge Oite inside piping, although the gas of interest is limited to gas mainly composed of natural gas, even if apartment is a case shared elevational tube is extremely long in high-rise To air diffusion by the long common vertical pipe In impact in consideration state, it is possible to dispense the air purge minimum necessary.

According to a second characteristic configuration of the present invention, the reference point is located on the ground, and the branch pipe from the common standing pipe of the second and higher floors of the apartment house, the gas meter portion attached to the branch pipe , or , there is to be carried air purge only Oite indoors side distribution pipe connected to the downstream side of the branch pipe.

According to the second characteristic configuration of the present invention, the reference point is located on the ground, and a branch pipe from a common vertical pipe of a dwelling unit on the second floor or higher of an apartment house, a gas meter portion attached to the branch pipe , or since only implement the air purge Oite indoor side distribution pipe connected to the downstream side of the branch pipe, in normal conditions, it is possible to meet the first characteristic configuration in which at least the foregoing, therefore, the air The portion to be purged can be easily identified.

In a third characteristic configuration of the present invention, the gas mainly composed of the natural gas is 13A.

According to the third characteristic configuration of the present invention, the gas mainly composed of natural gas is 13A, that is, 13A, which is actually widely used as city gas, and therefore, gas supply for a large number of existing housing complexes. In the facility, the air purge method according to the present invention can be applied as it is.

An embodiment of an air purge method for a gas supply facility according to the present invention will be described with reference to the drawings.
As shown in FIG. 1, this air purging method is implemented in a gas supply facility for a multi-storey apartment house such as a condominium or a public house. For example, a three-story condominium M has four units on each floor. If there are dwelling units M1 to M4 on the 1st floor, dwelling units M5 to M8 on the 2nd floor, and dwelling units M9 to M12 on the 3rd floor, each dwelling unit M1 to M12 has a main pipe 1 and a main pipe embedded in the ground. 1 through the lead-in pipe 2 buried in the ground, two common stand pipes 3 connected to the lead-in pipe 2, and a total of twelve branch pipes 4 branched from each common stand pipe 3, 13A, which is an example of a gas mainly composed of natural gas, is supplied, and a gas meter GM is attached to each branch pipe 4.

In the gas supply facility to the condominium M, for example, when the replacement work of the lead-in pipe 2 is performed, the vicinity of the upstream end of the common stand pipe 3 that is upstream (including the common stand pipe 3) from the common stand pipe 3 The pipes 2 and 3 are cut at A and the upstream end portion vicinity B of the lead-in pipe 2 and replaced with a new lead-in pipe 2.
In construction involving cutting of such pipes, the cutting point A is normally opened to the atmosphere for 60 minutes or more during the cutting of the existing pipe and the connection to the new pipe, and downstream of the cutting point A during that time. The air is mixed into the two common vertical pipes 3 and rises. Depending on the structure of the piping, air may also be mixed into the branch pipes 4 of the dwelling units M1 to M4 on the first floor.
The present inventor has tried to elucidate the rising mechanism of the mixed air with respect to the gas by repeating various experiments, and as a result, the increase of the air with respect to the gas in the common vertical pipe 3 is mainly due to the diffusion of the air to the gas. We found out that if the gas is a gas whose main component is natural gas, we obtained new knowledge that the distance from the opening is less than 2.5 m when opened for about 60 minutes. .

Furthermore, in order to confirm the effectiveness of this new knowledge, a confirmation experiment was conducted in a state in line with the actual construction, and the results will be mentioned.
As shown in FIG. 2, the first floor is 1.0 m, the second floor is 3.5 m, the third floor is 6.0 m, and the supplied gas is 6.0 m. 13A.
The common vertical pipe 3 was cut at the ground surface vicinity A, and then a new pipe was connected to close the cut portion A for 180 minutes.
Meanwhile, mainly at the time of cutting the existing pipe and connecting to the new pipe, the cut portion A of the common vertical pipe 3 was opened to the atmosphere for a total of 60 minutes.

Then, after the connection work of the new pipe was completed, the concentration of 13A in the common vertical pipe 3 was measured, and the value shown in FIG. 2 was obtained.
That is, with the cut point A as the reference point, the concentration from the reference point A along the common stand 3 in the height direction is 1.5% downstream at 94.5% and 2.0m downstream at 98.8%. However, it was 100% on the downstream side of 2.5 m, and 100% on the further downstream side.
From this result, it was confirmed that when the supply gas was 13 A, the opening distance from the opening location was less than 2.5 m when the gas was opened for 60 minutes and then closed for 180 minutes.

However, the above conclusion is for the case of a three-story condominium M with a floor of 6.0 m on the third floor, that is, the apartment M with a top floor of 6.0 m, and the length of the common standpipe 3 It has also been found that the rising height of the mixed air with respect to the gas increases as the length increases, that is, when the floor of the top floor exceeds 6.0 m.
As a result of investigating this point, it has been clarified that the rising height is increased by 2.3% of the total length of the common standpipe 3 in addition to the 2.5 m described above.
In other words, it was revealed that when the opening was made for 60 minutes, the rising height of the mixed air was {2.5 + L × (2.3 / 100)} m where the total length of the common standpipe 3 was Lm.
Therefore, assuming that the total length of the common standpipe 3 downstream from the reference point A is Lm, {2.5 + L × (2.3 / 100)} m or more in the height direction from the reference point A is located closest to the downstream side. It has been found that if the air purge is performed only in the gas meter GM portion, even a high-rise apartment M is sufficient.
And, if the reference point A is located on the ground, the air purge is performed only in the gas meter GM portion of the second floor or higher of the apartment M, so that at least the above-described configuration is satisfied under normal conditions. Can do.

Note that the place where the air purge is performed is not particularly limited to the gas meter GM portion. For example, the air purge can be performed at the branch pipe 4 from the common stand pipe 3 or at a specific place of the branch pipe 4.
Therefore, operation position of the air purge, shared elevational tube 3 branch pipe 4 from, gas meter GM portion mounted to the branch pipe 4, and any which indoor side distribution pipe connected to the downstream side of the branch pipe 4 It becomes.

Schematic diagram of gas supply equipment used in the experiment Explanatory drawing showing experimental results

DESCRIPTION OF SYMBOLS 1 Main pipe 2 Lead-in pipe 3 Common standing pipe 4 Branch pipe A Cutting point used as a reference point GM Gas meter M Apartment house M1-M12 Dwelling unit

Claims (3)

For each of a plurality of dwelling units constituting a multi-story apartment building, a main pipe buried in the ground, a main pipe connected to the main pipe, a common pipe connected to the main pipe, and a branch from the common pipe In a gas supply facility for supplying a gas mainly composed of natural gas through a branch pipe, after cutting the pipe on the upstream side of the common vertical pipe, the pipe is inserted into the pipe on the downstream side of the cut portion of the pipe. An air purging method for a gas supply facility that performs air purging for removing mixed air and replacing the gas.
The floor of the uppermost floor of the apartment building is over 6.0m, and the height of the common standpipe downstream from the reference point is Lm, where the cut point of the pipe is the reference point. {2.5 + L × (2.3 / 100)} m or more in the direction The branch pipe from the common standing pipe located closest to the downstream side, the gas meter portion attached to the branch pipe , or the downstream of the branch pipe air purging method for a gas supply facility for implementing the air purge only Oite indoors side distribution pipe connected to the side. The reference point is located on the ground, and is connected to a branch pipe from the common stand pipe of a dwelling unit on the second floor or higher of the apartment house, a gas meter portion attached to the branch pipe , or a downstream side of the branch pipe. air purging method for a gas supply system of claim 1, only carrying out the air purge Oite indoor side piping that. The gas purging method for a gas supply facility according to claim 1 or 2 , wherein the gas mainly composed of natural gas is 13A.

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