JPH02549Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a corrugated double wall pipe used for underground water distribution pipes, etc.

Conventionally, this type of corrugated double-walled pipe has a cylindrical inner wall 1 and an uneven outer wall 2 made of high-density synthetic resin material of the same composition, as shown in FIG. It was common to use heat-sealed materials. For such corrugated double wall pipes,
The inner surface is smooth, allowing water to flow smoothly, and the annular convex portion 21 formed on the outer wall 2 provides high earth pressure resistance, so it was preferably used for drainage pipes and the like as described above. However, such corrugated double-walled pipes have the drawback of being difficult to bend. That is, in the convex portion 21 of the outer wall 2, the outer wall 2 and the inner wall 1
It is difficult to bend the corrugated double-walled pipe at this part because a predetermined interval is maintained between
Since the inner wall 1 and the inner wall 1 are integrated by heat fusion, the wall thickness at that part is thicker and has high bending strength, so it is not possible to bend the corrugated double wall pipe at this part. It was difficult, and even if it could be bent, the radius of curvature would have to be extremely large, making it impossible to use it if it was necessary to bend it to a relatively small radius of curvature. .

This invention was made to improve the drawbacks of the conventional products. By providing raised folds in the recesses of the outer wall, the corrugated double-walled pipe has the same earth pressure resistance as the conventional product, but is easy to bend. The purpose is to provide

The present invention will be described below with reference to the illustrated embodiments.

In the corrugated double-walled pipe whose main part is shown enlarged in FIG. The above outer wall 2 excluding 22a
The recess 22 and the cylindrical inner wall 1 are heat-sealed. The inner wall 1 and the outer wall 2 are made of thermoplastic resin such as polyethylene or vinyl chloride. Note that it is desirable that the inner wall 1 and the outer wall 2 be molded from the same type of synthetic resin.

According to this, the recessed part 22 of the outer wall 2 becomes easy to bend due to the expansion and contraction action of the folded part 22a, and the corrugated double-walled pipe becomes bent at this part. Even in that case, the convex portions 21 of the outer wall 2 exhibit a large earth pressure resistance. Generally, when using a corrugated double wall pipe as an underground drainage pipe, if the inner diameter is 100 mm, the radius of curvature is 2 to 2.4.
It is said that it can be used in almost all construction areas if it is bent so that it becomes m, and it has been found that the above-mentioned corrugated double-walled pipe satisfies this requirement. In the illustrated example, the thickness of the inner wall 1 is made thinner than the thickness of the outer wall, but by doing so, the bending strength of the inner wall 1 can be kept low, so that corrugated double wall pipes can be used. It becomes more bendable. Also, for example, the outer wall 2
Even if high-density polyethylene is used for the inner wall 1 to increase the earth pressure resistance, if low-density polyethylene or the like is used for the inner wall 1, the bendability will not be significantly impaired.

FIG. 3 shows a modification. That is, the corrugated double wall pipe shown in the figure has a recess 22 in the outer wall 2.
An annular fold portion 22 having a shape that bulges inward.
b. This also provides the same bendability as the one in Figure 2, but when used as a drain pipe, the inner surface must be smooth, so the one in Figure 2 is better used as a drain pipe. Suitable. Other matters are the same as those explained in FIG.

In addition, in FIGS. 2 and 3, the pleats 22a,
22b is provided at one location in the recess 22 of the outer wall 2, but in this respect, the folds may be provided in a bellows shape over the entire area or part of the recess 22.

As detailed above, according to the present invention, it is possible to easily provide a corrugated double-walled pipe with high earth pressure resistance despite being easy to bend. It will not become unusable even in construction areas where it is required. Moreover, since the inner wall of the corrugated double-walled pipe of the present invention is formed into a cylindrical shape, water can flow smoothly when used as a drain pipe. In addition, when the corrugated double-walled pipe according to the present invention is used as an underdrain drainage pipe, a hole may be bored in the recessed part of the outer wall so as to communicate with the internal passage.

[Brief explanation of the drawing]

Fig. 1 is a partial sectional view of a conventional product, Fig. 2 is an enlarged sectional view of the main part of a corrugated double-walled pipe according to an embodiment of the present invention, and Fig. 3 is an enlarged sectional view of the main part of a modified example of the same. be. 1... Inner wall, 2... Outer wall, 22... Recessed portion of outer wall, 22a, 22b... Fold portion.

Claims (1)

[Scope of utility model registration request] A corrugated double-walled pipe formed by heat-sealing a cylindrical synthetic resin inner wall and an uneven synthetic resin outer wall, the corrugate double-walled tube having a raised pleat in the recessed part of the outer wall. Heavy walled pipe.