JPH01182031A - Manufacture of synthetic resin corrugated pipe - Google Patents

Abstract

PURPOSE:To make it possible to form a large diameter synthetic resin corrugated pipe near a working site, by winding a thermoplastic resin band sheet, a belt tape and a core material composed of flexible small-diameter tubular body spirally on a rotating cylindrical body through a heating range. CONSTITUTION:A core material D is composed of a flexible tubular body such as small diameter corrugated pipe. A band sheet B and a band tape C are heated to above their softening points by hot air or an infrared lamp as heat source, while they are wound around a quasi rotating cylindrical body A with an inclined angle on one side end thereof, applying said core material D between said sheet and tape. They are contacted and welded by means of a press roll F in such a way that the firstly wound band tape C and the secondly wound tape C are not overlapped each other and arranged in parallel, and then moved to the other end of the rotating cylindrical body A, cooled and hardened to form a pipe (a).

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a method for manufacturing a synthetic resin corrugated pipe used as water supply and drainage pipes for agricultural and civil engineering, industrial water supply and drainage pipes, etc. The present invention relates to a method for manufacturing a synthetic resin corrugated pipe that enables efficient and continuous molding of a large-diameter synthetic resin corrugated pipe with excellent watertightness near the construction site.

[Conventional technology]

Conventionally, methods for manufacturing this type of synthetic resin corrugated pipe are disclosed in Japanese Patent Publication No. 50-33112 and Japanese Patent Application Laid-open No. 56-895.
By spirally winding a core material and a belt-shaped body formed into a sheet or tube shape on a rotating shaft body such as a virtual cylindrical rotating shaft body as seen in Publication No. 31, these are fused. A method of manufacturing a synthetic resin corrugated pipe having a spiral unevenness formed by the core material on the surface is known.

[Problems to be solved by the invention] However, in the above manufacturing method, the product is extruded from an extruder,
Because the belt-shaped body, which is still in a semi-molten state, is manufactured by winding it around a rotating shaft, it is difficult to form it near the construction site. The transportation cost increases significantly because it has to be transported to the construction site, and furthermore, when winding the strip in a spiral shape on the top surface of the virtual cylindrical rotating shaft, one leaf of the strip is used, and it is necessary to wind the strip first. When the rolled strip and the later rolled strip overlap each other at the sides (due to the fact that they are wound to form a tube, if a thin strip is used, the above-mentioned Since the width of the polymerized portion has to be widened, productivity is significantly reduced. On the other hand, when a thick strip is used, it is not only difficult to obtain a uniform wall thickness due to the moldability of the strip. There were problems such as a difference in level occurring in the polymerized portion.

The present invention was invented to solve the above-mentioned drawbacks of the conventional method.It is an object of the present invention to provide a large-diameter synthetic resin corrugated pipe with a substantially smooth surface, uniform wall thickness, and excellent watertightness at a construction site. It is an object of the present invention to provide a method for manufacturing a synthetic resin corrugated pipe that can be efficiently and continuously molded near the pipe.

[Means for solving problems]

The present invention was invented in view of the above, and includes at least two thermoplastic resin strip sheets pre-formed to form the inner and outer surface layers of a tube, and an intermediate layer of the tube by laminating a plurality of layers. After heating a plurality of sheets of thermoplastic resin belt-like tape that have been pre-formed to form a sheet through a heating region to a temperature above the softening point and below the melting point, a layer is formed between the belt-like sheets forming the inner and outer surface layers. A band-shaped tape is interposed so that both sides of the band-shaped tape are shifted in the lateral direction so that they are not located on the same line with each other, and a flexible sheet is interposed between the band-shaped sheet forming the outer surface layer of the tube body and the band-shaped tape. While winding the virtual cylindrical rotating shaft in a spiral manner with a core material consisting of a small-diameter tubular body interposed therebetween, in this winding, at least the band-shaped tape wound first and the band-shaped tape wound later are wound. are wound so that they are arranged in parallel to each other without polymerizing to form a tube, and when the tube is still at a temperature above the softening point and below the melting point, the pressure roll is placed in contact with the virtual cylindrical rotating shaft. The problem was solved by pressure welding and cooling and hardening.

Hereinafter, the features of the present invention will be described in detail with reference to the drawings. Fig. 1 is a partially cutaway perspective view illustrating the manufacturing process of the present invention, and Fig. 2 is a tube body formed by the same manufacturing process. FIG. 3 is a partial cross-sectional view of the tube wall of another embodiment of the same, FIG. 4 is a partially cutaway cross-sectional view showing the manufacturing process of the same, and FIG. In the partially cutaway plan view shown,
In the figure, A is a virtual cylindrical rotating shaft body, and B is a thermoplastic resin strip sheet that forms the inner and outer surface layers of the tube body a, and is a strip sheet that has been previously formed into a long shape with a predetermined thickness and width. C is a plurality of thermoplastic resin strip tapes for forming the intermediate layer of the tube body a, and like the strip tape 1-B, a predetermined tape is prepared in advance. It is formed into a long piece with a thickness and width, and is rolled up into a roll. The core material is interposed between C and C, and is made of a small-diameter tubular body having flexibility, such as a small-diameter corrugated pipe. These band-shaped sheet B and band-shaped tape C are heated to a temperature above the softening point and below the melting point through a heating zone E using hot air, an infrared lamp, etc. as a heat source, and then between the band-shaped sheet B and the band-shaped tape L-B forming the inner and outer surface layers. A band-shaped tape C to be laminated is interposed with the positions shifted in the lateral direction so that both sides thereof are not located on the same line, and a band-shaped sheet B and a band-shaped tape C are interposed to form the outer surface layer B of the tube body a. With the core material interposed between them, the imaginary cylindrical rotary shaft body A is simultaneously supplied at an inclined angle to the circumferential surface of one end thereof, and is wound spirally. The rolled tape C and the tape C wound later are wound so as to be arranged in parallel with each other without polymerizing to form a tube body a, and the cough tube body a is still at a temperature higher than the softening point and lower than the melting point. At a certain temperature, the tube body a is formed by pressure-welding with a pressure roll F that is in contact with the virtual cylindrical rotating body 8, and cooling and hardening while transferring it to the other end side.

The virtual cylindrical rotating shaft body A shown here includes a plurality of rolls la, lb, 0. It consists of a set of rolls la, Ib, . The parts are rotatably supported by the base plate 2 and the bearing plate 3, and the entire combination substantially constitutes one virtual cylindrical rotating body, and each of the rolls la, lb, . Reference numeral 11 rotates the bearing plate 3 by a required angle in one direction with respect to the substrate 2, and connects one end of each roll 1a, 1b, . That is, by shifting each roll la, Ib, 1. By twisting and tilting li around the axis of the virtual cylindrical rotating shaft body A, the band-shaped sheet B and the band-shaped tape C are wound in a vI spiral shape.

Each of the rolls la, lb, .

9.11 are made to rotate in the same direction at a constant speed.

In addition, when the band-shaped sheet B used in the present invention is wound spirally around the virtual cylindrical rotating shaft body A in order to improve watertightness, the band-shaped sheet B used in the present invention is first wound.
It is made thinner and wider than the belt-shaped tape C so that it can be wound so that the tape and the later-wound belt-shaped sheet B overlap on the sides, and the step difference at the overlapped part after winding is extremely small. It is preferable to form the strip-shaped sheath B used as the upper surface layer, and the strip-shaped sheath B used as the upper surface layer may be formed into two layers as shown in FIG. On the other hand, because the tape C is relatively thick within the allowable range for molding, the fusion surface is made of thermoplastic resin with a relatively low softening point, such as low-density polyethylene, as shown in Figure 6. It is preferable to use a composite tape layered with .

〔Example〕

Hereinafter, the present invention will be described in more detail based on the embodiments shown in the drawings. Low-density polyethylene with a thickness of 0.5 mm is preformed and rolled into a roll to form the inner and outer surface layers of the tube body a. A two-lobed belt-shaped sheet B consisting of a sheet, and a belt-shaped sheet B having a thickness of 1 mm and a width of approximately 2 to form the inner surface layer of the tube body a, which is preformed to form an intermediate layer and rolled up into a roll. A four-leaf tape C made of a laminated sheet of a high-density polyethylene sheet and a low-density polyethylene sheet with a thickness of less than 1/2 is passed through a heating zone E using hot air as a heat source, and heated to a temperature above the softening point and below the melting point. The above-mentioned strip-like sheet 8 is arranged so that the two-leaf strip-shaped tapes C arranged in parallel are arranged in two stages, upper and lower, with their respective side parts of the four-leaf strip-shaped tape C aligned in the horizontal direction so that they are not located on the same line with each other.
A virtual cylindrical rotating shaft body A is formed by interposing a core material made of a small-diameter corrugated pipe between the belt-shaped sheet B and the belt-shaped tape C, which are interposed between them and form the outer surface layer of the tube body.
The tubular body a is wound spirally on top of the tube body a, and is wound so that at least the band-shaped tape C wound earlier and the band-shaped tape C wound later are arranged side by side with each other without overlapping. When the tube body a is still at a temperature higher than the softening point and lower than the melting point, it is pressed and fused with a pressure roll F that is in contact with the virtual cylindrical rotating shaft body A, and is cooled and hardened to form the shape shown in FIG. A band-shaped sheet 1-B with a substantially smooth inner surface and a core material enclosed in the outer surface as shown.
A tubular body a having spiral protrusions formed by swells was formed.

〔Effect of the invention〕

As is clear from the above, the present invention provides at least two preformed thermoplastic resin strip sheets, a plurality of thermoplastic resin strip tapes, and a core material consisting of a flexible small-diameter tubular body through a heating region. It is formed by winding it in a spiral shape on a virtual cylindrical rotating shaft, and the equipment is then transported to the construction site according to demand for continuous molding, which significantly reduces transportation costs. When winding the belt-shaped tape on the cylindrical rotating shaft, at least the belt-shaped tape wound earlier and the belt-shaped tape wound later are wound so as to be arranged side by side with each other without overlapping, thereby forming a tube body. As a result, a tube with a substantially smooth inner surface, which is the initial objective, is formed without the steps that occur in conventional polymerization. Characteristics include that moldability is greatly improved because they are wound at the same time, and watertightness is further improved because the laminated band sheets and band tapes are wound in different positions. It has the following.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view illustrating the manufacturing process of the present invention;
FIG. 2 is a partial cross-sectional view of a tube wall formed by the same manufacturing process as above, and FIG. 3 is a cross-sectional view of a tube wall of another embodiment of the same.
Fig. 4 is a partially cutaway sectional view showing the manufacturing process of the above, Fig. 5 is a partially cutaway plan view showing the same manufacturing process, and Fig. 6 is an example of the thermoplastic resin strip tape used in the present invention. It is a partially enlarged sectional view shown. A--Virtual cylindrical rotating shaft body B--Strip sheet C--Strip tape D--Core material E--Heating zone F--Press roll a--Tubular body

Claims (4)

[Claims] (1) At least two thermoplastic resin strip sheets preformed to form the inner and outer surface layers of the tube, and a plurality of thermoplastic resin sheets preformed to form the middle layer of the tube by laminating multiple layers. After heating the plastic resin strip tape through a heating region to a temperature above the softening point and below the melting point, the strip tape to be laminated is placed between the strip sheets forming the inner and outer surface layers so that both sides of the strip tape are mutually connected. A core material consisting of a flexible small-diameter tube is interposed between the strip sheet and the strip tape, which are interposed with their positions shifted in the lateral direction so as not to be located on the same line, and which form the outer surface layer of the tube. While being wound spirally on a virtual cylindrical rotating shaft while intervening,
During this winding, at least the first-wound tape strip and the second-wound tape strip are wound so that they are arranged side by side with each other without polymerizing to form a tube, and the tube is still melted above its softening point. At a temperature below 100 yen, the sheet is pressure bonded with a pressure roll that is in contact with a virtual cylindrical rotating shaft body, and is cooled and hardened, so that the inner surface is substantially smooth and the outer surface is bulged by enclosing a core material. A method for manufacturing a synthetic resin corrugated pipe, characterized by continuously manufacturing a pipe body having a spiral protrusion. (2) When winding the belt-like sheet in a spiral shape on the virtual cylindrical rotating shaft, the belt-like sheet is wound so that the first-wound belt-like sheet and the second-wound belt-like sheet overlap at the sides. A method for manufacturing a synthetic resin corrugated pipe according to claim 1. (3) A method for manufacturing a synthetic resin corrugated pipe according to claim 1, characterized in that the belt-shaped sheet is made thinner and wider than the belt-shaped tape. (4) The method for manufacturing a synthetic resin corrugated pipe according to claim 1, characterized in that a composite tape consisting of a laminate of a high-density polyethylene tape and a low-density polyethylene tape is used as the band-shaped tape.