JPH0630732B2 - Gas pipe installation method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing a gas pipe using a flexible pipe.

[0002]

2. Description of the Related Art In recent years, gas pipes have been installed not only in multi-dwelling houses where the conditions of gas work such as piping space and relationships with other equipment are severe, but also in detached houses under the floor, in the wall,
Since the space such as the ceiling is narrow, it is difficult to use gas pipes only with rigid pipes. As a result, it takes a lot of time for piping work, and outdoor exposed pipes are forced.

Therefore, a piping method using a flexible long flexible pipe as a piping material (hereinafter referred to as a flexible piping method) was developed, and this piping method can be relatively easily piped in a narrow space such as a wall. Since the construction time is shortened, the influence on the construction process due to the delay in gas piping work can be reduced, and there are many advantages such as no gas leakage from the joints and easy maintenance because there is no joint in the middle. Therefore, it is being actively promoted.

On the other hand, since the material used for the gas pipe is limited in terms of safety, in order to obtain the required flexibility, it is possible to give the flexibility by forming the pipe wall in a corrugated form, that is, forming a bellows shape. It is necessary, and currently, a flexible metal pipe made of metal such as stainless steel is used in the flexible pipe construction method.

[0005]

However, the pipe constructed by the conventional flexible pipe construction method using the flexible pipe having the corrugated pipe wall as described above is a white gas pipe having the same diameter as the conventional structure due to the structure of the flexible pipe. Since the pressure loss is larger than that of, the gas supply efficiency is reduced.

Therefore, it is necessary to increase the diameter of the flexible pipe or to arrange a plurality of pipes in parallel in order not to reduce the gas supply capacity.

The present invention has been made in view of the above problems of the prior art. The object of the present invention is to further develop a flexible piping construction method using a flexible pipe having a corrugated pipe wall, and to perform the construction by the construction method. Nevertheless, it is necessary not to reduce the gas supply capacity.

[0008]

In order to achieve the above-mentioned object, in the gas pipe piping construction method of the present invention, in the pipe construction of the gas pipe using the metal flexible pipe having the corrugated pipe wall, A resin layer having a uniform inner diameter as close to the inner diameter as possible is formed in the flexible tube.

In the present invention, the inner diameter of the flexible pipe means the effective diameter of the portion of the flexible pipe protruding inward.

[0010]

According to the pipe construction method for the gas pipe constructed as described above, since the flexible pipe has no unevenness on the inner surface and becomes flat, the pressure loss is reduced.

[0011]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of piping in an apartment house. As shown in FIG. 1, from a header 4 connected to a gas meter 3 to a required gas appliance 5 indoors and outdoors, a gas outlet 6, and a gas pipe through the wall and under the floor. It is piped.

A flexible pipe 1 is used for the construction of the gas pipe. This flexible tube 1 is shown in Fig. 2 and below.
As is well known, it has the same structure as that used in the conventional flexible piping method, and is made of a bellows-shaped stainless pipe that is flexible by forming the pipe wall 1a into a corrugated shape, and has an outer peripheral surface. It is covered with a synthetic resin coating material (not shown).

Then, first, the flexible pipe 1 is piped by a conventionally known flexible pipe construction method.

Subsequently, a synthetic resin 2a is lined on the inner surface of the flexible pipe 1 piped by the above process to form a resin layer 2
To form.

The synthetic resin 2a is, for example, an epoxy resin-based elastic adhesive which is not corroded by gas, and the amount of resin required for lining is previously determined from the pipe diameter and the extension of the pipe.
Mix so that the weight ratio of the curing agent is 1: 1 and after mixing,
It is immediately injected into the flexible pipe 1 and, as shown in FIG. 3 , a pig 7 is used to line the entire surface of the pipe.

The method of injecting the resin 2a into the flexible tube 1 is arbitrary, but as a simple method, it is conceivable to inject it by using a caulking gun 8 or the like as shown in FIG .

At this time, a blower or the like may be connected to the end of the flexible pipe 1 on the resin injection side to blow pressurized air with a low air volume and a low pressure into the pipe 1 to push the injected resin to the other end. good.

The pig 7 is formed in a spherical shape or an elliptic spherical shape having a diameter substantially the same as or slightly smaller than the inner diameter of the flexible tube 1 and is connected to the wire 9 to be injected with the flexible tube 1 after resin injection.
By inserting it inside and pulling and moving it from the resin injection side end to the other end, the resin 2a is washed away in the moving direction, and the resin 2a is applied to the inner surface of the pipe 1 while filling the recess 1b in the flexible pipe 1 with the resin. .

At this time, the pig 7 is reciprocated several times if necessary.

As a result, the concave portion 1b in the flexible tube 1 is filled with the resin 2a, and the lined resin layer 2 is formed on the entire surface of the tube 1 as shown in FIG.

Since the pig 7 has substantially the same diameter as the inner diameter of the flexible tube 1, the inner diameter of the resin layer 2 is substantially the same as the inner diameter of the flexible tube 1, and the inner diameter is uniform over the entire length of the tube. Will have.

In the above description, the resin layer 2 is formed by lining the flexible tube 1 with the synthetic resin 2a.
It is also possible to form the resin layer 2 having a flat inner peripheral surface in the flexible tube by inserting a synthetic resin hose or a thin tubular film into the flexible tube 1.

Thus, a comparison was made between the flexible tube having the flat inner surface in this way and the flexible tube having the corrugated inner surface without providing the resin layer by using the measurement of the pressure loss per 1 m. The results shown in the graph were obtained.

The measuring method is a constant differential pressure between the inlet side and the outlet side of a flexible pipe having a corrugated inner surface without a resin lining of 25A and 32A and a flexible pipe having a resin inner surface and a flat inner surface. (0.2mmH2O ~ 2.0mmH2O)
The flow rate was adjusted with 5C gas and the flow rate at that time was measured.

From the above measurement results, it has been proved that the pressure loss is reduced by lining the flexible pipe to make the inner surface flat, as compared with the flexible pipe without the lining.

That is, when the inner surface is made flat by lining or the like, the flow rate increases by about 20% with the same pressure loss.

This corresponds to a pressure loss of the flexible pipe 25A which is almost the same as that of a steel pipe having the same diameter.

No. 16 water heater (30,000 kcal / h) with a flexible pipe lined based on the above measurement results
And water heater with No. 16 additional heating (40,000 kcal / h)
Table 1 shows the calculation of the possible piping extension when the is installed with a constant allowable pressure loss.

[0030]

[Table 1] It can be seen that the pipe extension is increased by about 1.5 to 2.0 times by making the inner surface flat by applying the lining as described above.

[0031]

As described above, the present invention forms a resin layer having a uniform inner diameter as close as possible to the inner diameter of the flexible pipe in the pipe construction of the gas pipe using the metal flexible pipe having the corrugated pipe wall. The following effects are achieved. (1) Despite using a flexible pipe with a corrugated pipe wall, the pressure loss is small, and the flow rate is greatly increased in the same extension with respect to the gas pipe with the corrugated inner surface that was piped by the conventional flexible piping method without lining. To increase.

Therefore, it is not necessary to use a flexible pipe having a large pipe diameter or to provide a plurality of pipes in parallel so as not to reduce the gas supply capacity. (2) As compared to the conventional flexible pipes that were laid by the method without a resin layer on the inner surface as described above, the flow rate is greatly increased in the same extension, so it is possible to lengthen the pipe extension and install it due to pressure loss until now. The number of cases that can be installed in places where it was not possible increases. (3) Since the inner surface of the metallic flexible tube is covered with the synthetic resin layer, the corrosion resistance to water is improved, and even if the gas contains water, the water does not corrode. (4) Since the resin layer is formed on the inner surface of the flexible pipe after piping, the workability of the flexible piping method is not impaired.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an example of a state in which a pipe is piped by a flexible pipe construction method, and is partially cut away.

FIG. 2 is an explanatory diagram showing an example of a state in which a lining resin for forming a resin layer is injected into a flexible pipe after piping.

FIG. 3 is an explanatory view showing an example of a lining step (resin layer forming step).

FIG. 4 is a cross-sectional view of the flexible pipe after completion of the lining process (resin layer forming process).

FIG. 5 is a graph showing the measurement results of the pressure loss of a flexible pipe provided with a resin layer on the inner surface in comparison with a flexible pipe having no resin layer.

[Explanation of symbols]

 1: Flexible pipe 1a: Pipe wall 2: Resin layer 2a: Resin

Claims (1)

[Claims] 1. In a gas pipe piping construction using a metal flexible pipe having a corrugated pipe wall, a resin layer having a uniform inner diameter as close as possible to the inner diameter is formed in the flexible pipe after piping. How to install gas pipes.