JPH102462A - Polyolefin pipe for waterline and water pipeline using polyolefin pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent oil odor from shifting into a pipe without worsening workability and earthquake resistance. SOLUTION: The periphery of a pipe body 12 is formed of polyolefin resin so as to be full of flexibility, and wound with an aluminium tape 14 leaving joint margins A at both ends to form an outer layer. A thus formed polyolefin pipe 10 for waterline is buried as a water pipeline in an area with soil contaminated with oil, or an area with such concern. Accordingly, even though oil reaches the periphery of the polyolefin pipe 10, the oil is shut out by the aluminium tape 14 to prevent the pipe body 12 from coming in direct contact with the oil and swelling, and the flexible property of the pipe body 12 is not impeded by the aluminium tape 14 forming the outer layer of the pipe body 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyolefin pipe for water service and a water pipe line using the polyolefin pipe, and more particularly, to a water pipe which is buried in an oil-soil-contaminated area such as a gas station or a petroleum tank vehicle plant, or an area where there is a possibility of such a situation. And a water pipe using the polyolefin pipe.

[0002]

2. Description of the Related Art Conventionally, as a water pipe buried underground, a polyolefin pipe made of a polyolefin-based synthetic resin having high flexibility in consideration of earthquake resistance and the like is applied. here,
Since the difference in solubility parameter between polyolefin resin and petroleum-based solvents (gasoline, kerosene, etc.) is small, if gasoline or kerosene touches the polyolefin tube, the polyolefin resin will swell and the density of the tube will decrease. . Then, the odor of oil such as gasoline or kerosene is transferred to the tap water inside the polyolefin pipe, and when the tap water is used for drinking water, a complaint may be caused due to the odor or taste.

[0003]

In order to prevent such an oil odor from migrating, a steel pipe (a cast iron pipe) that does not penetrate the oil odor around the outer periphery of the polyolefin pipe only in an area where there is a risk of soil contamination by the oil. ) Or a PVC tube as a sheath tube. However, when a sheath tube is used, there is a problem that workability is poor because both the polyolefin tube and the sheath tube are required. Also, the flexibility of the polyolefin tube itself is limited by the sheath,
There was a problem that sufficient earthquake resistance could not be secured.

[0004] Therefore, a main object of the present invention is to provide a polyolefin pipe for water service which can prevent the transfer of oil odor without deteriorating workability and earthquake resistance. Another object of the present invention is to provide a water pipe using a polyolefin pipe, which can prevent the transfer of oil odor without deteriorating workability and earthquake resistance.

[0005]

According to a first aspect of the present invention, an outer layer made of a metal tape is formed on a water pipe made of a polyolefin-based synthetic resin and buried underground, with at least a joining margin at one end. It is a polyolefin water pipe characterized by the following. A second invention is a polyolefin water pipe characterized in that a coating layer made of a synthetic resin having a gas permeability smaller than that of the polyolefin pipe is formed on a water pipe buried underground, which is made of a polyolefin-based synthetic resin. is there.

According to a third aspect of the present invention, in a water pipe buried underground using a polyolefin pipe, the polyolefin pipe is covered with a gas permeation preventing coating layer at least in an area where soil is contaminated by oil or in an area where there is a possibility of this. It is a water pipe using a polyolefin pipe.

[0007]

In the first and second aspects of the present invention, the oil in the soil is blocked by the outer layer made of metal tape or the coating layer made of synthetic resin formed on the outer periphery of the polyolefin water pipe. Therefore, the oil does not touch the outer periphery of the polyolefin tube, and the tube does not swell. In addition, since only the outer layer or the coating layer is formed on the polyolefin water pipe, it is lighter in weight than the case of using a steel pipe or the like which is a coating pipe, and the polyolefin resin is rich in flexibility. Properties are not impaired.

In the third invention, a water pipe is laid using a polyolefin pipe coated with a gas permeation prevention coating layer. This conduit is lighter than the case of using a steel pipe (cast iron pipe) or the like as a cladding pipe, and the flexible property of the polyolefin resin is not hindered by the gas permeation prevention coating layer. Further, the oil in the soil is blocked by the gas permeation prevention coating layer, and the oil does not reach the outer periphery of the pipe. Therefore, the polyolefin tube is not swollen by contact with the oil.

[0009]

According to the first, second and third inventions,
Even if a lightweight and flexible polyolefin water pipe is used, oil does not come into contact with the outer periphery of the pipe and the pipe does not swell, so the transfer of oil odor does not deteriorate workability or earthquake resistance. Can be prevented.

The above objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A water supply polyolefin pipe 10 of this embodiment shown in FIGS. 1 and 2 is used for a water pipe laid underground, and is used to prevent soil contamination caused by oil at a gas station or an oil tank vehicle plant. Applicable to areas of concern, including tube body 12.

The tube main body 12 is a fixed length tube made of a polyolefin resin having high flexibility such as polyethylene. The dimensions of the tube body 12 are set to an outer diameter of 20 mm or more and a total length of about 5 m.
When the thickness is 0 mm, the thickness is set to about 8.5 mm. An aluminum tape 14 is wound around the outer periphery of the tube body 12 to form an outer layer. Further, the aluminum tape 14 is not wound from both ends of the tube main body 12 to a position of a predetermined length, and a joint margin A with a socket of another tube is formed.

Here, a commercial product is used for the aluminum tape 14 and its thickness is about 0.1 to 0.3 mm, and an adhesive layer for adhering to the tube body 12 is formed on one surface. Further, the joint allowance A of the pipe main body 12 is set corresponding to the outer diameter D of the pipe main body 12. For example, when the outer diameter D of the pipe main body 12 is 90 mm, the joint allowance A is 60 mm, and the outer diameter D is 125 mm.
In this case, the joining margin A is set to about 80 mm.

When the aluminum tape 14 is wound around the outer periphery of the tube main body 12, as shown in FIG. 3, the aluminum tape 14 is spirally wound from one end of the tube main body 12 while leaving the above-mentioned joining margin A. At this time, as shown by a broken line in FIG.
4 is wound around the aluminum tape 14 already wound around the tube body 12 so as to overlap a predetermined length. FIG.
As shown in (B), even when the tube body 12 is deformed by the bending force, the outer peripheral surface of the tube body 12 is exposed from the overlapping portion of the aluminum tape 14 due to the displacement of the overlapping portion of the aluminum tape 14. This is to prevent it.

When the water supply polyolefin pipe 10 thus formed is connected to another pipe to form a water pipe, another pipe having a socket as shown in FIG. 5 or FIG. 20 or socket tube 22 is used. The pipe 20 shown in FIG. 5 is made of the same polyolefin resin as the pipe main body 12. One end of the pipe 20 has an inner diameter slightly larger than the outer diameter of the pipe main body 12 and a length substantially equal to the joining margin A of the polyolefin pipe 10. A mouth 24 is formed. A heating wire 26 is built in an inner peripheral surface of the receiving port 24, and a terminal 28 communicating with the heating wire 26 is provided on an outer periphery of the receiving port 24.

When connecting the polyolefin pipe 10 to the pipe 20, first, one end of the polyolefin pipe 10 is connected to the pipe 20.
Is inserted into the receiving port 24. Next, in this state, a power supply (not shown) is connected to the terminal 28, the heating wire 26 is heated to heat and melt the inner peripheral surface of the receiving port 24, and the tubes 10 and 20 are fused. Thereafter, the aluminum tape 14 is wound around the outer periphery of the tube 20 similarly to the polyolefin tube 10, and the outer periphery of the tube 20 and the receiving port 24 is completely covered with the aluminum tape 14.

The length of the socket pipe 22 shown in FIG.
Is formed in a cylindrical shape having an inner diameter slightly larger than the outer diameter of The heating wire 30 is built in the inner peripheral surface of the socket tube 22, and a terminal 32 communicating with the heating wire 30 is provided on the outer periphery of the socket tube 22. When connecting two polyolefin tubes 10 using the socket tube 22, first, one end of each polyolefin tube 10 is inserted from both ends of the socket tube 20 to the vicinity of the center of the socket tube 22. Next, in this state, a power supply (not shown) is connected to the terminal 32, the heating wire 30 is heated to heat and melt the inner peripheral surface of the socket tube 20, and the polyolefin tube 10 and the socket tube 22 are fused. Thereafter, the aluminum tape 14 is wound around the outer periphery of the socket tube 22 in the same manner as the polyolefin tube 10, and the connection portion between the two polyolefin tubes 10 is completely covered with the aluminum tape 14.

Referring to FIG. 7, when the water pipe is laid in the soil-contaminated area B with oil, first, a groove for laying the water pipe is excavated, and then the polyolefin pipe 10 is piped. This is laid in the groove while being sequentially joined using the socket 20 or the socket tube 22. Then, as described above, the aluminum tape 14 is also wound around the joining portion, and finally, the groove is back-filled with soil.

In the water pipe laid underground in this way, oil in the soil around the polyolefin pipe 10
Even when the oil reaches the outer periphery of the polyolefin tube 10, the oil is blocked by the aluminum tape 14 as the outer layer. Therefore, since the oil does not directly touch the pipe main body 12, the pipe main body 12 is not swollen by the oil. Further, even if a bending force acts on the polyolefin pipe 10 due to ground displacement such as an earthquake, the pipe main body 12 is flexibly deformed following the ground displacement. Since the outer peripheral surface of the tube main body 12 is not exposed from the overlapping portion of the aluminum tape 14 as shown in FIG. 4B, there is no possibility that the tube main body 12 will be swollen by contact with oil.

The degree of the effect of preventing the oil odor from penetrating into the pipe main body 12 depends on the thickness of the pipe main body 12 and the aluminum tape 14, the ambient temperature, the burial depth, the degree of soil contamination, and the water supply. It also depends on environmental factors such as water residence time.
Therefore, when laying a water pipe, it is necessary to investigate conditions under which complaints due to unpleasant odor of tap water do not occur in the laying environment, and to construct the pipe so as to satisfy the conditions.

In general, the amount of toluene mixed in tap water is 24-170 μg / l (0.024-0.170 ppm).
About 20 to 1800 μg / l (0.
It is known that complaints due to unpleasant odors occur at about 020 to 1.800 ppm). In addition, the amount of mixed toluene was 7
It is known that human health is affected when the amount of xylene is about 500 μg / l (0.500 ppm) or about 00 μg / l (0.700 ppm). Therefore, the content of toluene is 24 μg / l (0.024 ppm).
Hereinafter, the amount of xylene mixed is 20 μg / l (0.0
It is desirable to set various conditions so as to be 20 ppm) or less. However, with regard to off-flavors, there is a large variation in the permissible range between regions, and if too strict standards are set, the actual situation may not be met. Therefore, it may be considered acceptable if the amount of oil mixed is 0.1 ppm or less.

According to this embodiment, the polyolefin tube 1
Numeral 0 is obtained by winding an aluminum tape 14 around the pipe main body 12, which is lighter than the case where a steel pipe or the like, which is a conventional cladding pipe, is used, so that workability is good. Further, even if a bending force acts on the polyolefin pipe 10, the pipe body 12 is flexibly deformed following the displacement of the ground without being swollen by oil, so that the inside of the pipe body 12 is not deteriorated without deteriorating the earthquake resistance. The odor of the oil can be prevented from migrating.

In the above-described embodiment, the case where a commercially available aluminum tape 14 is used as the metal tape forming the outer layer of the tube main body 12 has been described, but a metal tape such as a steel tape is used in addition to the aluminum tape 14. You can also. Also,
The coating layer may be formed using a tape or the like made of a resin material having a gas permeability smaller than that of the polyolefin resin instead of the metal tape described above. Such materials include, for example, hard vinyl chloride, nylon (6,6
6), vinylidene chloride, PET (polyethylene terephthalate) and the like can be used. Table 1 below shows gas permeability of polyethylene as an example of the polyolefin resin and hard vinyl chloride as an example of the coating layer.

[0024]

[Table 1]

[Brief description of the drawings]

FIG. 1 is an illustrative view showing one embodiment of the present invention;

FIG. 2 is an illustrative view showing one embodiment of the present invention;

FIG. 3 is a perspective view showing a method of winding an aluminum tape around a pipe main body.

FIG. 4 is an illustrative view showing a state in which a bending force of a pipe main body is applied;

FIG. 5 is an illustrative view showing a state where the embodiment of FIG. 1 is connected to a pipe having a receptacle;

FIG. 6 is an illustrative view showing a state where the embodiment of FIG. 1 is connected using a socket tube;

FIG. 7 is an illustrative view showing a water pipe using the embodiment in FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Polyolefin pipe for water supply 12 ... Pipe main body 14 ... Aluminum tape 22 ... Socket pipe 24 ... Receptacle 26, 30 ... Heating wire 28, 32 ... Terminal A ... Joining allowance D ... Outer diameter of pipe main body

Claims (3)

[Claims] 1. A water pipe made of a polyolefin-based synthetic resin and buried in the ground, wherein an outer layer made of a metal tape is formed except for a joining margin of at least one end. 2. A water pipe made of a polyolefin-based synthetic resin and buried underground, wherein a coating layer made of a synthetic resin having a gas permeability smaller than that of the polyolefin pipe is formed. 3. A water pipe buried underground using a polyolefin pipe, wherein the polyolefin pipe is coated with a gas permeation prevention coating layer at least in a soil-contaminated area by oil or in an area where there is a danger of this. A water pipe using a polyolefin pipe.