JPS6144162B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel synthetic resin underdrain drain pipe.

Underdrain drainage pipes are subject to large earth pressures, so they must have excellent earth pressure resistance. However, as shown in Figure 4, a small water permeable hole b in an extremely thick pipe a...
If a general underdrain drainage pipe with a structure in which many holes are bored is manufactured from synthetic resin, a large amount of resin is required, which is disadvantageous from an economical and resource saving perspective, and the weight It was also disadvantageous in terms of portability due to its large size. Not only that, but such drainage pipes are naturally limited in water permeability aperture ratio because the earth pressure resistance strength decreases if excessive water permeability holes b are drilled, and the water absorption efficiency is also unsatisfactory. It was something.

Focusing on this point, various synthetic resin underdrain drain pipes have recently been developed, but the reality is that there are hardly any that are fully satisfactory.

In view of the above circumstances, the present invention has developed a synthetic resin that uses a relatively small amount of resin and is lightweight, yet has a thick pipe wall, high earth pressure resistance, and is also excellent in water absorption efficiency. The purpose is to provide underdrain drainage pipes.

The underdrain drainage pipe of the present invention will be described in detail below with reference to the drawings. Fig. 1 is a schematic vertical cross-sectional view of an embodiment of the present invention, and Fig. 2 is a schematic cross-sectional view of the same embodiment, with the illustrations As shown in the figure, the present invention uses thick synthetic resin right helical thread 11......
. . . are fused at their intersections to form a net cylindrical frame 1, and a large number of thin synthetic resin threads 2 are irregularly bent in the diameter direction and run in the axial direction on the outer periphery of the frame 1. This relates to an underdrain drain pipe that is made by fusing together...

Right helical thread 11 constituting the mesh tubular frame 1...
………… and left helical thread 12 ………… are made of hard synthetic resin such as high-density polyethylene (preferably
In this example, the inner right helical thread 11 and the outer left helical thread are used. Three threads 12 are arranged alternately at equal angular intervals, and the overlapping intersections are fused. Such frame 1
are helical threads 11 and 12.
It is desirable to reduce the total number of the helical threads 11 and to reduce the angle θ, and narrow the pitch interval of the helical threads to increase the pressure resistance.
... and 12...... are preferably made of very thick threads with a generally oval cross section that are long in the diametrical direction of the drain pipe to further increase the pressure resistance. To give an example of a suitable mesh cylindrical frame 1, for example, the outer diameter is 10~
A frame suitable for obtaining a culvert drainage pipe of about 15 cm has 4 to 12 right helical threads 11 and left helical threads 12, and the thickness of each helical thread is the length of the long diameter. The intersection angle θ of the helical thread is approximately 0.4 to 1.5 cm.
One example is a net cylindrical frame in which the angle is approximately 10 to 90 degrees, and the pitch intervals of the right and left helical yarns are both approximately 0.5 to 4 cm. An underdrain drainage pipe using such a frame has a flattening strength (20% deformation) of at least 1 t or more per meter, and is sufficiently durable for civil engineering applications.

In addition, in the embodiment shown in the figure, the right helical thread 11...
Although the left helical thread 12 is arranged on the inside and the left helical thread 12 is on the outside, it goes without saying that they may be arranged in the opposite relationship. . . . 12 .

A large number of thin threads 2 of synthetic resin running in the axial direction are fused to the outer periphery of the mesh cylindrical frame 1 as described above. Helical threads 11 and 12 of frame 1
An extremely thick tube wall A having a substantially triple structure is formed. This tube wall A has a permeable gap 3 sufficient to prevent the passage of soil grains formed between the thin threads 2 on the surface, and the thin threads 2... ...and helical thread 11......, 12
It has a high water permeability aperture ratio with large water permeable gaps 3' between......, and in particular, in the present invention, the thin threads 2......... are irregularly bent. Accordingly, more water permeable gaps 3 are formed than in the case where the thin threads 2 are provided linearly, thereby further improving the water permeable aperture ratio. Such thin threads 2 may be made of either the same hard synthetic resin as the mesh cylindrical frame 1 described above, or other semi-hard or relatively hard synthetic resin. From the viewpoint of increasing impact resistance strength, semi-hard or relatively soft synthetic resin fine threads having excellent tensile strength and impact absorption properties are more preferably employed. There are no particular restrictions on the thickness or number of such thin threads 2, but for example, when making an underdrain drainage pipe with an outer diameter of about 10 to 15 cm, the diameter of the thin threads should be approximately 0.1 to 15 cm. 0.5cm, the number of pieces is approx.
It is appropriate to set the number in the range of 50 to 150.
In this embodiment, the thin threads 2 are provided in a single layer on the outer periphery of the net cylindrical frame 1, but they may be provided in double or triple layers depending on the case.

The above is the basic configuration of the present invention, but furthermore,
If necessary, attach an appropriate synthetic resin film-like material 4 or the like as shown in the illustration to the water surface inside the drain pipe, or
Alternatively, it is desirable to use other appropriate means to reduce the roughness coefficient of the water surface inside the drain pipe and make it smooth so that the water absorbed into the drain pipe can flow smoothly.

To manufacture the underdrain drain pipe of the present invention as described above, a thick thread of synthetic resin is extruded in a helical shape through mutually reversible inner and outer double rotating dies x and y as illustrated in FIG. ...... and left spiral thread 12
. . . are fused at their intersections to form a net cylindrical frame 1 continuously, and before this frame 1 is solidified, a large number of Synthetic resin thin thread 2...
This can be easily and efficiently carried out by extruding . . . along the frame 1 and fusing the thin threads 2 . . . to the frame 1.
In this case, the net cylindrical frame 1 and the thin thread 2......
If the take-up speed is slower than the extrusion speed of...
The intersecting angle θ of 2... can be adjusted to a small value, and the thin thread 2 can also be made to slide.

As described above, the underdrain drainage pipe of the present invention is made of a net cylindrical frame in which thick right helical threads 11 and left helical threads 12 made of synthetic resin are fused at their intersections. The right helical thread 11 is made by fusing a large number of thin synthetic resin threads 2 running in the axial direction around the outer periphery in a sliding state in the diameter direction.
..., left helical thread 12...... and surface thin thread 2
As a result of this, an extremely thick tube wall A having a substantially triple layer structure is formed, so that a large earth pressure resistance strength can be obtained despite the small amount of resin used. This effect is especially noticeable when the helical yarn 1
1......, 12...... are very thick threads with approximately oval cross sections that are long in the drain pipe diameter direction, and when the intersection angle θ of both helical threads is made small to narrow the pitch interval, it is better to It becomes even more remarkable. In addition, if the thin threads 2 on the surface are made of a semi-hard or relatively soft synthetic resin as described above, the impact resistance will be improved and the drain pipe will be extremely durable.
In addition, in the drain pipe of the present invention, the helical thread 11...
The gaps formed between all the threads of ..., 12...... and thin thread 2 are the water permeable gaps 3...
and 3'......, the water permeable opening ratio of the tube wall A is high, and the water that has entered through the small water permeable gaps 3 between the thin threads 2 on the surface is as follows:
The thin thread 2...... and the helical thread 11......
12. Large permeable gap 3'…… between...
Since it is quickly attracted by the water and flows into the drain pipe, the water absorption efficiency is greatly improved. This effect becomes even more remarkable because the thin threads 2 on the surface are bent in the diameter direction to increase the water permeable aperture ratio. Furthermore, when the flowing water surface is made smooth by means such as pasting the film-like material 4 on the inner flowing water surface as in the previously described embodiments, there is an additional effect that the absorbed moisture flows smoothly. There is an effect.

As described above, the underdrain drain pipe of the present invention is useful because it has a high earth pressure strength despite the small amount of resin used, and also has a large water permeable aperture ratio and a good water absorption rate.

[Brief explanation of the drawing]

FIG. 1 is a partial cross-sectional schematic diagram of an embodiment of the culvert drain pipe of the present invention, FIG. 2 is a schematic cross-sectional diagram of the same embodiment, and FIG. FIG. 4 is a partial perspective view of a conventional underdrain drain pipe. (Explanation of main symbols in the drawings), 1...Mesh tubular frame, 11...Right helical thread, 12...Left helical thread, 2...Thin thread, 3, 3'...Water gap, 4...Film shaped object, A... tube wall, θ... intersection angle.

Claims (1)

[Claims] 1 A thick right helical thread 11 and a left helical thread 12 made of synthetic resin are fused at their intersections to form a net cylindrical frame 1, and a diameter is set on the outer periphery of this frame 1. A large number of thin synthetic resin threads 2 that are irregularly bent in the direction and run in the axial direction...
Underdrain drain pipe made by fusing together.