JPH0434195Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to improvement of synthetic resin underdrain drain pipes used for agricultural and civil engineering purposes.

[Conventional technology]

There are various types of underdrain drain pipes, but those made of synthetic resin can be broadly divided into five types.
A regular polyvinyl chloride pipe, that is, a cylindrical pipe with many small holes, a pipe with a net shape as a whole, a corrugated pipe with alternating peaks and valleys in the form of a thread or ring. A pipe with a small hole in the pipe, a pipe with thick and thin parts connected alternately and a small hole in the thin part, and an improved version of the corrugated pipe.
There are cylindrical types with a wavy exterior and a smooth inner wall.

[Problem that the invention attempts to solve]

Each of these underdrain pipes has advantages and disadvantages.

The functions of an underdrain drainage pipe are (1) excellent earth pressure resistance as it is a pipe buried underground, (2) good water absorption, and (3) smooth inner wall surface for good water flow. (4) It must be lightweight, easy to carry, and easy to carry out construction, but as culvert burying work has become mechanized in recent years, one important requirement is to lengthen the culvert (that is, to have flexibility). It has come to be mentioned as

If we look at the above-mentioned drain pipe from the above-mentioned functions, we can see that a regular circumferential pipe made of polyvinyl chloride cannot be made long. A pipe whose entire structure is mesh-like has problems with its inner surface smoothness and earth pressure resistance. So-called corrugated pipes, in which only the outer wall is corrugated, can be made longer, but the inner surface is not smooth and water flow is poor.
In addition, a corrugated double-walled pipe with a smooth inner surface has been developed as an improved version of this corrugated pipe, but it has problems with flexibility and is difficult to wind.
Once rolled, a curl remains. A pipe in which thick and thin walls are connected alternately has earth pressure resistance in the thick wall part,
Although it has a thin wall and is flexible, there is a problem that it will tear from the thin wall if both ends of the tube are pulled with strong force.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention alternately and integrally connects a thick annular part made of synthetic resin and a number of thin bands arranged in parallel at predetermined intervals along the annular part. , and the thin strip is uniaxially stretched so that its inner surface is substantially flush with the inner surface of the annular portion.

[Effect of invention]

This invention has a thick annular part, so it is strong against earth pressure, and the many thin bands integrally connected along the annular part can be bent freely, so even if it is long. It can be wound, and since the thin-walled bands are uniaxially stretched, the tensile strength is very strong.Moreover, the spacing between the thin-walled bands is moderately wide, allowing sufficient water to infiltrate through the gaps. . Furthermore, when the underdrain drain pipe that has been wound for transportation or storage is unwound at the underdrain construction site, since the thin band portion is stretched, there is little curling and it is easy to return to a straight shape. Furthermore, since the inner surface of the annular portion and the inner surface of the thin band are substantially flush with each other, and the inner surface of the tube is smooth, solid matter is less likely to clog and can be drained smoothly.

〔Example〕

Examples of the present invention will be described in detail below.

FIG. 1 is a perspective view showing one embodiment of the present invention, in which 1 indicates high-density polyethylene, polypropylene,
This is an underdrain drain pipe made of thermoplastic synthetic resin such as polyvinyl chloride. Reference numeral 2 denotes a thick-walled annular portion which can also be referred to as the aggregate of the underdrain drainage pipe 1, and 3 refers to a large number of thin-walled bands arranged in parallel at predetermined intervals along the annular portion 2. It extends in the length direction of the tube 1.

The thickness of the annular portion 2 varies depending on the diameter of the drain pipe 1, and as the diameter increases, the thickness must also increase. When the diameter of the underdrain drain pipe 1 is 50 mm, the thickness of the annular part 2 is about 2.0 to 4.0 mm, and the width of the annular part 2 is about 4 to 8 mm, considering the strength of the drain pipe and the entire pipe. This is suitable from the viewpoint of flexibility. Further, if the drain pipe 1 has a large diameter of about 200 mm, the thickness of the annular portion 2 should be about 2.5 to 5.0 mm. The thickness of the annular portion 2 is not necessarily limited to the above numerical values, and varies depending on the material of the underdrain drain pipe, and also depending on its use.

On the other hand, the thin band 3 is half the thickness of the annular part 2.
It is desirable that the amount is less than 1/2, and it becomes almost impossible to wind it. In order to ensure pressure resistance in the annular part 2, normal underdrain drainage pipes use hard synthetic resin, so for example, if the annular part 2 has a thickness of 2 mm, but the thin strip 3 is 1 mm, it is almost in good condition. It cannot be wound around. Therefore, the thickness of the thin band 3 is one-half or less of the thickness of the annular portion 2, preferably one-fourth to one-seventh of the thickness, which is a condition for good winding of the drain pipe. I can say that.

Further, the thickness of the thin band 3 varies depending on the thickness of the annular portion 2 and the stretching ratio. This means that
This is due to the method of connecting the underdrain drain pipe of the present invention, and this point will be briefly explained below. Figure 2 shows a high-density polyethylene pipe 10.
1, 12, 13... are extremely small circular holes. When this pipe 10 is stretched with strong force in the direction of arrow X, small holes 11, 11..., 12, 12..., 1
The strength is weak where the small holes are lined up from 3, 13... to 15, 15..., and between 11, 11... and 12, 15...
At the same time as the space between 12... and 15, 15... is extended, the small hole is also extended to become an elongated gap. This is the gap 4 created in FIG. Also, conversely, 11 and 1
There are no holes between 2, 12 and 13 to 14 and 15, so that part is stronger than the others, and since it is not stretched, it remains as a thick annular part, and 1
The areas between 1 and 11 and between 12 and 12 and between 15 and 15 are stretched to form a thin band shape, and are displaced in the centripetal direction of the pipe 10 so as to alleviate the strain caused by the stretching, and the inner surface thereof is approximately in the same plane as the inner surface of the annular portion. become one.

In this way, the thick annular part becomes the annular part 2 in FIG. 1, and the thin band becomes the thin band 3. Therefore, the pipe 10 shown in FIG. 2 is stretched in the direction of arrow X, and cut lengthwise between the small holes.
Fig. 3 shows the end face. The part 23 between the small holes 11 and 11 in FIG. 2 is the thin band 23 in FIG. 3, and the part 22 between the small holes 11 and 12 in FIG. This is a thick annular portion 22 .

Although the above embodiment uses a pipe with small holes drilled in it, the underdrain drainage pipe of the present invention can also be manufactured by similarly extending a small mesh pipe in the length direction. As can be understood from the above explanation, the thin band 3 was originally the same thickness as the annular part 2 but was stretched and became thinner, so the thickness of the thin band 3 is the same as the thickness of the annular part 2 and It depends on the magnification. For example, if the underdrain drain pipe 1 has a diameter of 60 mm and the annular portion 2 has a thickness of about 2 mm, the thin band 3 will have a thickness of about 0.4 mm by being stretched five times. The elongated gap between one thin-walled band 3 and the adjacent thin-walled band 3 is originally a small hole, but it has been stretched and becomes elongated.

The underdrain drain pipe 1 thus manufactured has pressure resistance due to the thick annular portion 2 and sufficient flexibility due to the thin band 3. In addition, the elongated gap can be formed freely depending on the shape of the small hole drilled before being stretched, so if an underdrain drainage pipe with high water absorption is required, the small hole 1 in Figure 2 can be formed.
1...15 can be easily manufactured by opening a large number of them in slightly larger sizes.

Further, although the end surface 22 of the annular portion is square in FIG. 3, it is not necessarily square. 4 to 6 are enlarged sectional views of the annular portion 22. When the width of the annular portion 22 is small, it becomes a mountain shape as shown in FIG. 4, and when the width is a little wide, it becomes a shape as shown in FIG. As the width becomes wider, the upper part becomes completely flat and completely unaffected by stretching, as shown in FIG.

[Effect of idea]

The synthetic resin underdrain drainage pipe of this invention has a thick annular part, so it has excellent earth pressure resistance, and the numerous thick bands integrally connected to the annular part can be bent freely. Since it can be wound, the underdrain drain pipe can be made into a long body. Furthermore, since the thin strip is uniaxially stretched, it has high tensile strength. Therefore, when a long rolled underdrain drain pipe is loaded at the rear of a trencher and buried at the same time as trench digging, it will not break easily even if a strong tensile force is applied to the underdrain drain pipe during burying. This has the effect of allowing construction to be carried out extremely smoothly and quickly. also,
The strength can be adjusted freely by increasing or decreasing the thickness of the thick part, and thick parts are used where pressure resistance is required, and conversely, thick parts are used where pressure resistance is not required. It has the advantage that it can be freely selected, such as a relatively thin one. In addition, there is a suitable gap between the thin-walled bands, which allows sufficient water to be absorbed into the pipe, and since it is uniaxially stretched, it is easy to return to a straight shape when unwound, so construction work is easy. Not only is it easy to install, but it can also be buried accurately by setting a predetermined slope, and since the inner surfaces of the annular portion and the thin band are substantially flush with each other and the inner surface of the tube is smooth, it has the effect of allowing water to flow smoothly.

[Brief explanation of drawings]

Fig. 1 is a perspective view of an underdrain drainage pipe showing an embodiment of the present invention, Fig. 2 is a synthetic resin perforated pipe showing the state before the underdrain drainage pipe of Fig. 1 is made,
The figures are end views of the stretched pipe in Figure 2 cut in the length direction, Figures 4, 5, and 6.
Each figure is an enlarged cross-sectional view of the annular portion 22. 1...Underdrain drain pipe, 2...Annular part, 3...Thin wall band, 10...Pipe.

Claims (1)

[Scope of utility model registration request] A thick annular portion and a large number of thin bands arranged in parallel at predetermined intervals along the annular portion are alternately and integrally formed, and the thin bands are uniaxially stretched so that the inner surface thereof forms the annular portion. A synthetic resin underdrain drain pipe characterized by being substantially flush with the inner surface of the pipe.