JPH0225778B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a synthetic resin pipe in which a metal reinforcing member is embedded in a rib portion integrally provided on a pipe wall.

As pipes to be buried underground, conventionally used are hume pipes, steel pipes, asbestos pipes, reinforced plastic composite pipes, etc., which are lightweight and have excellent pressure resistance.
This tendency is particularly strong for large-diameter pipes. However, hume pipes and steel pipes have problems in handling due to their corrosion resistance, chemical resistance, and heavy weight, which greatly limits their uses, and they also have drawbacks such as high manufacturing costs. In addition, asbestos pipes, glass fibers, and reinforced plastic composite pipes are expensive to manufacture, and in the case of reinforced plastic composite pipes in particular, manufacturing is too labor-intensive and requires a large amount of raw material usage, which inevitably increases costs.

In addition, ribbed synthetic resin pipes made from thermosetting synthetic resins such as polyester resin have excellent pressure resistance, corrosion resistance, and chemical resistance; The material is manufactured using the so-called hand lay-up method, in which mat-shaped glass fibers are covered and polyester resin is applied in multiple layers using a coating brush and cured. and the cost is high. This manufacturing method is adopted not only because of the nature of the raw material, which makes it impossible to extrude synthetic resin pipes when thermosetting synthetic resin is used as a raw material, but also because metal reinforcing members are attached to the ribs. This is because there was no suitable means for embedding it in the synthetic resin layer.

The present invention provides an inexpensive long tube with excellent pressure resistance even though the raw material of the synthetic resin tube is a thermoplastic synthetic resin, in which the rib portion in which the metal reinforcing member is embedded and the tube wall are integrally formed. It is an object of the present invention to provide a long synthetic resin pipe, and also to provide a manufacturing apparatus that can easily and continuously mold such a long synthetic resin pipe by a continuous injection molding method.

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

In the long synthetic resin pipe 100 illustrated in FIG. 1, the pipe wall 101 and rib portions 102 are integrally formed at a plurality of locations on the pipe wall 101 at predetermined intervals.
is made of thermoplastic synthetic resin. As the thermoplastic synthetic resin, it is possible to use, for example, polyvinyl chloride, polypropylene, polyethylene and others.

FIGS. 2A, 2B, and 2C show details of the rib portion 102 formed on the tube wall 101 and its vicinity. The metal reinforcing members 103 used in these are all ring-shaped, and their cross-sectional shapes are T-shaped in the figure A, U-shaped in the figure B, and U-shaped in the figure B.
The one in Figure C is L-shaped. Same figure A, B,
As is clear from C, the reinforcing member 103 is not only embedded in the rib portion 102 but also extends into the resin layer forming the tube wall 101 on the side of the rib portion 102. Extension portion 104 of lever
is embedded in the resin layer.

With this configuration, the long synthetic resin pipe 100 has the following advantages: the rib portion 102 is reinforced by the reinforcing member 103, the tube wall 101 is reinforced by the rib portion 102 reinforced in this way, and the rib portion 102 is reinforced by the reinforcing member 103. Due to the synergistic effect that the pipe wall 101 is reinforced by the extending portion 104 of the reinforcing member 19
3 reliably reinforces the corner portion of the boundary between the rib portion 102 and the tube wall 101, so that cracks do not occur in the root portion of the rib portion 102 where stress tends to concentrate, that is, the corner portion, or the boundary portion is damaged. No more cracking. Therefore, the long synthetic resin pipe 100 has enough strength and durability to be used as a substitute for the above-mentioned hume pipe, steel pipe, asbestos pipe, and reinforced plastic pipe. In addition, 30% is added to thermoplastic synthetic resin as a raw material.
It is of course possible to use polypropylene filled with glass fibers. In addition to the true cylindrical shape shown in FIG. 1, the long synthetic resin pipe 100 may have a polygonal shape such as an elliptical cylinder or a square cylinder. It is desirable to use circular, elliptical, and polygonal rings, respectively.

Next, an apparatus for manufacturing a synthetic resin pipe using the above-mentioned thermoplastic synthetic resin as a raw material will be explained.

In the synthetic resin pipe manufacturing apparatus illustrated in FIG. 4, 1 is a molten resin extrusion section, and the end of the molten resin passage 11 of this molten resin extrusion section 1 is flat as shown in FIG. Molten resin injection ports 12 having a small diameter are formed by openings at equal pitches at a plurality of locations on a virtual circle X set on the end face. Further, a pipe forming core 2 is supported in the molten resin extrusion section 1 in a cantilevered manner, that is, in a protruding state. Further, on the end face of the molten resin extrusion part 1 around the fixed end of the pipe forming core 2, protruding support mechanisms 3 are provided at multiple locations (three locations in the illustrated example) at equal angles. These support mechanisms 3 are configured to be able to support a metal reinforcing member 108 in a fitted manner.

Next, as clearly shown in FIG. 4, a pair of upper and lower split shapes 4, 4 are arranged at the front of the molten resin extrusion section 1.
The split molds 4, 4 are formed by dividing a mold block having a cylindrical molding surface 41 into two vertically. A pair of split molds 4, 4 are configured to be able to move back and forth between spaced positions, and when these split molds 4, 4 are set at the molding position, their end faces are exposed to the molten resin extrusion. It is adapted to come into contact with the end surface of part 1. Also split 4,
Space portions 42 and 43 are provided at two locations in the axial direction of 4. One of these spaces 42 is provided in a concave shape with respect to the cylindrical molding surface 41, and is opened at the end faces of the split molds 4, 4, so that the split molds 4, 4 are set at the molding position. When the opening 42a is opened, the opening 42a faces the molten resin injection port 12, as shown in detail in FIG. Furthermore, as clearly shown in the figure, a reinforcing member 108 supported by the above-mentioned support mechanism 3 is disposed in this space 42.
As clearly shown in FIG. 4, the other space 43 is provided in the intermediate portion near the front ends of the split shapes 4, 4 in a concave manner with respect to the cylindrical molding surface 41. The diameter of this space 43 is set to be the same as the diameter of the space 42 described above, but the width thereof is set to be larger than the width of the space 42.

Next, the effect will be explained.

FIG. 7A shows a case where the end portion including the rib portion of the molded synthetic resin pipe 100A is accommodated in the other space 43 and held by the pair of split molds 4, 4. That is, the synthetic resin pipe 100A has a pipe wall 10.
1A is provided with a rib portion 102A in which a metal reinforcing member 103A is embedded in the end portion of the rib portion 102A.
is housed in the space 43, so that the split mold 4,
It is held at 4. Note that the rib portion 102A is a portion molded in the space 42 of one of the split molds 4, 4 in the previous molten resin extrusion process, and therefore one surface of the reinforcing member 103A is exposed on one side of the rib portion 102A. There is. In addition, at the very first stage of molding, the above-mentioned molded synthetic resin pipe 100A
You can use its imitation instead. Also the 7th
FIG.
Also shown is a case in which the pipe forming core 2 is inserted and supported in a pipe, and in this state, the pipe forming core 2 is supported on both sides.

FIG. 7B shows a space S for forming a pipe wall formed between the cylindrical molding surface 41 of the split molds 4, 4 and the pipe forming core 2 opposed thereto (Figs. 4 and 7). The case is shown in which thermoplastic synthetic resin P is injected in a molten state into (see). That is, the thermoplastic synthetic resin P is injected in a molten state from the molten resin injection port 12 shown in detail in FIG. 5 into the space 42 of one of the split molds 4, 4 shown in FIG. Space S for pipe wall forming
and is pushed out to the other space 43 and filled therein. As a result, the end of the synthetic resin pipe 100A that is in contact with the molten thermoplastic synthetic resin P, that is, a part of the rib portion 102A, is heated and melted, and the two are thermally fused and integrated, and the initially synthetic resin pipe 100A The reinforcing member 103A, which was held by the rib portion 102A and one side of which was exposed on one side of the rib portion 102A, is now embedded in the rib portion 102A.

FIG. 7C shows the case where the pair of split molds 4, 4 are moved to the mold release position after the thermoplastic synthetic resin P explained in FIG. 7B has hardened. From this state, the synthetic resin pipe 100B molded in the process of FIG. 7C is pulled in the direction of the arrow in FIG.
Pull it out. Then, the rib part 102B of the synthetic resin pipe 100B, which is the part formed by the one space part 42 (see FIG. 7A), is inserted into the other space part 43.
(See Figure 7 A) and hold it.

After that, the reinforcing member 103 is supported on the support mechanism 3 → the thermoplastic synthetic resin P is injected into the tube wall molding space S (see Fig. 7B) → the thermoplastic synthetic resin P is hardened → the mold is released (the By sequentially repeating steps (see FIG. 7C), the long synthetic resin pipe 100 described in FIGS. 1 and 2 can be continuously molded without any length restriction.

Metal reinforcing member 10 to be supported by the support mechanism 3
It goes without saying that the shape of 3 may be ring-shaped with an I-shaped cross section as shown in FIGS. 4 to 7, as well as those explained in FIGS. It is. When the reinforcing member 103 explained in FIG. It is arranged over a space S of . In addition, Figure 7 A,
In (b) and (c), the same elements are given the same reference numerals, and detailed explanations thereof are omitted.

Since the long synthetic resin pipe of the present invention is made of thermoplastic synthetic resin as a raw material, it has excellent corrosion resistance and chemical resistance. The reinforcement of the pipe wall by the rib part and the reinforcement of the pipe wall by the extended part of the rib part have a synergistic effect, resulting in extremely high pressure resistance. Therefore, the corner portion of the boundary between the rib portion and the tube portion is reliably reinforced, so that cracks do not occur in the corner portion where stress tends to concentrate, and the boundary portion does not break. Therefore, the above-mentioned long synthetic resin pipes include the above-mentioned hume pipes, steel pipes, asbestos pipes,
It has enough strength and durability to be used as a replacement for reinforced plastic pipes.

Next, according to the synthetic resin pipe manufacturing apparatus according to the present invention, it is possible to continuously mold a synthetic resin pipe with high pressure resistance, in which a metal reinforcing member is embedded in the rib part that is integral with the pipe wall. Synthetic resin pipes with high pressure resistance and strength made from thermoplastic synthetic resin can be easily and inexpensively manufactured.

[Brief explanation of drawings]

Fig. 1 is an external perspective view of a long synthetic resin pipe according to an embodiment of the present invention, and Fig. 2 A, B, and C show synthetic resin pipes having rib portions embedded with metal reinforcing members of various shapes. FIG. 3 is an enlarged cross-sectional view of the main part of a long synthetic resin pipe manufactured by the manufacturing apparatus according to the embodiment of the present invention, and FIG. 5 is a front view of the extrusion part in the same manufacturing device, FIG. 6 is an enlarged sectional view of the main part of FIG. 4, and FIGS. 7 A, B, and C show the operation of the above manufacturing device. FIG. 1... Molten resin extrusion part, 12... Molten resin injection port,
2... Core for pipe line formation, 3... Support mechanism, 4... Split mold,
41... Cylindrical molding surface, 42, 43... Space part, 42a
... Opening of space, 100 ... Long synthetic resin pipe, 10
DESCRIPTION OF SYMBOLS 1... Pipe wall, 102... Rib part, 103... Metal reinforcing member, 104... Extension part of reinforcing member, S... Space for forming pipe wall.

Claims (1)

[Scope of Claims] 1. A tube wall is integrally provided with a rib portion projecting outward from the tube wall, and these rib portions are molded from thermoplastic synthetic resin and are embedded in the rib portion. The reinforced metal reinforcing member is extended to the inside of the resin layer forming the tube wall on the side of the upper rib portion, and the extended portion is embedded in the resin layer. A long synthetic resin pipe. 2 A molten resin extrusion part with a molten resin injection port opened at an end face is configured to be movable back and forth between a molding position where they abut each other and a position where they are spaced apart from each other, and at the molding position, the end face of the molten resin extrusion part is in contact with the molten resin extrusion part. a pair of split molds that abut against the end faces, the split molds having a cylindrical molding surface for molding the outer surface of the tube wall, and projecting to the outside of the tube wall at two locations in the axial direction. An annular space for molding the rib part provided integrally with the pipe wall is recessed in the cylindrical molding surface, and one of these spaces is is opened at the end face of the split mold, the other space has the same diameter as one space and is wider than the other space, and the end includes a rib part of a molded synthetic resin pipe. The molten resin extrusion section faces the cylindrical molding surface of the split mold at a distance, and forms a space for tube wall molding between the cylindrical molding surface and the cylindrical molding surface. It is equipped with a core for forming a pipe channel in a protruding state, and has a molten resin injection port facing the opening of one of the spaces of the split mold set at the molding position, and has a melt resin injection port facing the opening of one of the spaces of the split mold set at the molding position, and has a mold for forming the pipe wall between the one space and the pipe wall. A projecting support mechanism is provided in a protruding state at a plurality of locations on the end face of the molten resin extrusion part to support in a fitted state a metal reinforcing member disposed across the space. Equipment for manufacturing long synthetic resin pipes.