JPH0241422Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to composite pipes, and is particularly suitable for chemical plants, water supplies, raw material transportation, district heating and cooling, etc. where temperature characteristics are important.

[Conventional technology]

Conventionally, as a composite pipe used for chemical plants, water supply, district heating and cooling, etc., there is one shown in Japanese Utility Model Publication No. 51-53450. This product consists of a fiber-reinforced synthetic resin inner layer, an intermediate layer formed by laminating a wood sand layer and a foamed synthetic resin layer, and a synthetic resin outer layer.

[Problem that the invention attempts to solve]

However, since the inner layer of this product is made of a fiber-reinforced synthetic resin layer, unevenness of the fibers occurs on the inner surface.
Since it is not smooth, the flow resistance inside the pipe increases, making it unsuitable for use as fluid transport piping. In addition, when joining this composite pipe on-site, the outer layer is forcibly peeled off while making cuts with a saw etc. and heating it at about 200 degrees Celsius. Because it was firmly attached to the layer, it was impossible to peel it off cleanly.

Therefore, the present invention was devised in view of the above points, and an object of the present invention is to provide a composite pipe that has less flow resistance inside the pipe and is easy to process.

[Problem that the invention attempts to solve]

In order to achieve the above object, the present invention includes a solid layer of thermoplastic resin, a foam layer of foamable thermoplastic resin integrally molded around the outer periphery of the solid layer, and a foam layer laminated around the outer periphery of the foam layer. It is characterized by being composed of a glass cloth layer and an outer layer in which a glass roving is laminated on the outer periphery of the glass cloth layer by filament winding molding.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.A composite pipe 1 includes a solid layer 2 whose inner layer is made of thermoplastic resin such as vinyl chloride resin, and which is integrally molded around the outer periphery of the solid layer 2. A foamed layer 3 made of foamable thermoplastic resin such as foamed vinyl chloride resin, a glass cloth layer 4 laminated surrounding the outer periphery of the foamed layer 3, and a filament winding of glass roving around the outer periphery of the glass cloth layer 4. It is composed of an outer layer 5 laminated by molding.

The solid layer 2 is a chemical-resistant layer, and is determined by the type of fluid, temperature, design life, etc.
Regarding the wall thickness, for example, for a pipe with a diameter of 100 mm, it should be 2 mm or more.

Further, it is advantageous in terms of cost to mix sand, calcium carbonate, etc. into the foam layer 3,
Furthermore, if this outer surface is made into an embossed shape or a frosted shape, the adhesive force with the glass cloth layer 4 is improved.

Furthermore, since the glass cloth layer 4 functions to suppress the deflection of the inner layer caused by changes in internal pressure, etc., the glass cloth layer 4 is attached to the foam layer 3.
It is best to wrap it around more than the ply.

Furthermore, for the outer layer 5, the winding angle of the glass roving and the type of resin impregnated into the glass fibers may be changed depending on various conditions such as the internal pressure of the composite pipe 1, the fluid, the installation environment of the composite pipe 1, etc. The ideal wrapping angle for the glass roving is 55°±10° in the direction of the tube axis, and if Surf Smat is used on the outer surface, the appearance will be improved.

In this example, it is preferable that the ratio of the ideal thickness structure of each layer is: solid layer 2: foam layer 3: glass cloth layer 4: outer layer 5 = 2:5:1:2.

[Effect of idea]

As described above, the present invention consists of a composite tube with a solid layer of thermoplastic resin, a foam layer of foamable thermoplastic resin, a glass cloth layer, and an outer layer of glass roving wrapped in order from the innermost layer by filament winding molding. As a result, the strength is increased, and the thickness of the solid layer is less than 1/2 that of conventional products.Also, a glass cloth layer is interposed between the foam layer and the outer layer wrapped with glass roving. When joining composite pipes on-site, the outer layer can be quickly peeled off, and the cuts made in the outer layer can be prevented from extending into the inner layer, which prevents the strength of the inner layer from decreasing and also prevents tension in the tube axis direction. Strength and bending strength are also improved.

Moreover, even if internal pressure is applied, the glass cloth layer is interposed, so the outer glass roving does not stretch and the shape inside the tube does not change.

[Brief explanation of the drawing]

The figure is a partially cutaway perspective view showing an embodiment of the present invention. 1... Composite pipe, 2... Solid layer, 3... Foamed layer,
4...Glass cloth layer, 5...Outer layer.

Claims (1)

[Scope of utility model registration request] A solid layer of thermoplastic resin, a foam layer of foamable thermoplastic resin integrally molded around the outer periphery of the solid layer, a glass cloth layer laminated on the outer periphery of the foam layer, and an outer periphery of the glass cloth layer. A composite tube characterized by comprising an outer layer of glass roving laminated by filament winding molding.