JPH04272831A - Manufacture of eccentric thickness fiber reinforced resin pipe - Google Patents

Abstract

PURPOSE:To readily form an uneven thickness fiber reinforced resin pipe by injecting resin mortar between a core mold and an outer mold for forming an uneven thickness intermediate layer, and then winding resin-impregnated glass fibers again around the intermediate layer after curing for forming an outer layer. CONSTITUTION:Resin impregnated glass fibers are wound round the outer periphery of a circular cross-sectional core mold 1 for forming an inner layer F1. One outer mold 2A is concentrically attached to the core mold 1 and the other outer mold 2B is attached by interposing spacers 3,3 in the outer mold 2A, which is fixed eccentrically with respect to the core mold 1 at a thickness of the spacers. Furthermore, resin mortar is injected between the core mold 1 and the outer molds 2A,2B for forming an eccentric intermediate layer 4M, and resin impregnated glass fibers F are wound round the intermediate layer 4M again after curing for forming an outer layer F2. In the next place, the outer layer F2 is cured and then the three layers F1. 4M, F2 are integrated for obtaining an uneven thickness fiber reinforced resin pipe.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing fiber-reinforced resin tubes with uneven wall thickness.

0002

BACKGROUND OF THE INVENTION Conventionally, fiber-reinforced resin pipes have been widely used as underground pipes due to their excellent corrosion resistance.

0003

[Problems with the prior art] By the way, the above-mentioned fiber-reinforced resin pipe (
FRP pipes (hereinafter referred to as "FRP pipes") have inferior strength compared to cast iron pipes and steel pipes, so when used as pipes buried in ultra-high embankments, which have become popular in recent years, there was a problem that the pipe tops would buckle and fail due to lack of strength. One possible measure to prevent such buckling failures is to use pipes with thick walls to withstand the earth pressure of ultra-high embankments, but the locations where buckling fractures occur are mostly limited to the top of the pipe. The above-mentioned method cannot be said to be very economical since high loads are not applied to the tube sides or the tube bottom. Therefore, it is desirable to use an unevenly walled tube with a thicker wall only at the top of the tube, but F
Since RP pipes are formed by winding resin-impregnated glass fibers around a core mold, it is extremely difficult or almost impossible to form pipe walls with uneven thickness. there were.

0004

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention provides a method for manufacturing an FRP pipe with uneven wall thickness, which can be easily manufactured using a conventional core mold and outer mold. This was done for the purpose of obtaining.

[0005]

[Means for solving the problem] That is, the FRP of the present invention
The method for manufacturing uneven wall tubes is to form an inner layer by winding resin-impregnated glass fiber around the outer periphery of a core mold with a circular cross section, and then insert the outer mold, which is split into two in the axial direction, into the glass fiber. When erecting the tube wall thickness apart from the outer periphery, one outer mold is attached concentrically to the inner mold, and the other outer mold is attached to the one outer mold with a spacer interposed between them. The other outer mold is eccentrically fixed to the core mold by the thickness of the spacer, and resin mortar is injected between the core mold and the outer mold to form an intermediate layer with uneven thickness, and then hardened. Afterwards, resin-impregnated glass fiber is wound again on the intermediate layer to form an outer layer, thereby integrating the three layers.

[0006]

[Example] Next, an example of the present invention will be described. FIG. 1 is a cross-sectional view showing the steps of the method of the present invention, FIG. 2 is a cross-sectional view showing the external shape of the present invention, FIG. 3 is a plan cross-sectional view showing the same state of use, and FIG. 4 is a final step of the method of the present invention. FIG.

As shown in FIG. 1, the method for producing a fiber-reinforced resin tube with uneven wall thickness includes winding resin-impregnated glass fibers F around the outer periphery of a core mold 1 having a circular cross section to form an inner layer F1. Then, the outer molds 2A and 2 were split into two in the axial direction.
When fixing B with a distance equal to the tube wall thickness, as shown in FIG. The spacers 3, 3 are interposed, and the other outer mold 2B is eccentrically fixed to the core mold 1 by the thickness t of the spacers 3, 3, and the core mold 1 and the outer mold 2A are fixed. , 2B, as shown in FIG. 3, a resin mortar 4 is injected to form an uneven thickness intermediate layer 4M, and after curing, resin-impregnated glass fiber F is wound again on the intermediate layer 4M, as shown in FIG. It consists of a step of integrating three layers F1, 4M, and F2 by forming and curing the outer layer F2.

In the above, the core mold 1 and the outer mold 2A,
2B is used for molding resin mortar tubes with uniform wall thickness as shown in FIG.

[0009]

[Operation] When placing the outer mold after uniformly winding the resin-impregnated glass fiber around the core mold 1, the outer mold 2A is placed concentrically with respect to the core mold 1. Its installation is easy. When arranging the other outer mold 2B, it is joined to one outer mold 2A via the spacers 3, 3, so if even one outer mold 2A is positioned correctly, Installation is easy.

[0010] When the core mold 1 and the outer molds 2A and 2B are installed, the outer periphery of the core mold 1 has a mold with uneven thickness on the half circumference of the other outer mold 2B. The space becomes S. Therefore,
By injecting resin mortar 4 here and hardening it, a fiber-reinforced resin pipe with uneven wall thickness can be formed. Therefore, even if the resin-impregnated glass fiber is wound after that, the thickness of the whole will be uneven.

[0011]

[Effects of the Invention] As explained above, according to the present invention, it is possible to easily manufacture an FRP mortar uneven-walled pipe using the conventionally used core mold and split-type outer mold. It is. Further, since the state of the uneven thickness can be adjusted only by adjusting the thickness of the spacer inserted between the outer shapes, it is very easy to implement and can be manufactured at low cost.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the steps of the method of the invention.

FIG. 2 is a plan sectional view showing the state in which the mold used in the method of the present invention is used.

FIG. 3 is a longitudinal cross-sectional view showing the state of use of the mold used in the method of the present invention.

FIG. 4 is a cross-sectional view showing the final step of the method of the invention.

[Explanation of symbols]

1 Core mold 2A, 2B Outer mold 3 Spacer 4 Resin mortar 4M Middle class F Resin-impregnated glass fiber F1 Inner layer F2 Outer layer

Claims (1)

[Claims] Claim 1: An inner layer is formed by winding resin-impregnated glass fiber around the outer periphery of a core mold having a circular cross section, and then an outer mold split into two in the axial direction is separated from the outer periphery of the glass fiber. When erecting the tubes apart by the wall thickness, one outer mold is attached concentrically with the inner mold, and the other outer mold is attached to the one outer mold with a spacer interposed between them. The other outer mold is eccentrically fixed with respect to the core mold by the thickness, and a resin mortar is injected between the core mold and the outer mold to form an uneven thickness intermediate layer, and after curing, A method for producing a fiber-reinforced resin uneven-walled tube, which comprises winding resin-impregnated glass fibers again on the intermediate layer to form an outer layer and integrating the three layers.