JPH0343505Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a composite pipe used for transferring fluids such as submarine water pipes, road heating pipes, geothermal hot water transfer pipes, and gas pipes.

(Prior art and problems to be solved) Conventionally, metal pipes and plastic pipes such as polyethylene and polyvinyl chloride have been used as pipes for fluid transfer such as submarine water pipes, road heating pipes, and gas pipes. However, in all cases, the cross-sectional shape was circular and constant.

Therefore, especially when transferring liquids such as water, hot water, hot spring water, etc., scale will adhere and grow on the inner surface of the pipe after long-term use, not only significantly increasing the pressure loss but also, in extreme cases, causing scale to grow. This was a major problem, as the scale could clog the pipes, making it impossible to transfer liquid.

A composite pipe that solves the above problems and prevents scale from growing on the inner surface of the pipe.
This was previously proposed by the inventor of the present application. (Tokugansho
60-21371) Figure 2 shows a cross-sectional view of an example of such a composite pipe, in which a freely deformable inner pipe 1 having an elliptical cross-sectional shape and having a fluid transfer passage 3 inside.
An outer pipe 2 having a fixed shape, such as a metal pipe made of stainless steel or steel, or a plastic pipe made of polyethylene or polyvinyl chloride, is provided on the outside of the pipe.

Therefore, the fluid transfer passage 3 inside the inner pipe 1, which is free to deform, is normally used to transfer water, hot water, hot spring water, etc., but if necessary, the pressure of the fluid flowing through the fluid transfer passage 3 may be reduced. Alternatively, the fluid transfer is stopped at regular intervals or for a certain period of time to remove the hydraulic pressure, and gas or the like is introduced into the space 4 formed by the outer pipe 2 having a fixed shape and the inner pipe 1 which is free to deform. The purpose is to apply pressure from the external pressure of the inner pipe 1 to deform it, thereby preventing the adhesion and growth of scale.

However, during long-term use of such composite pipes, the inner pipe made of polyethylene, etc., which is free to deform, may become flattened or deform in the longitudinal direction of the pipe, and if the outer pipe is even slightly deformed, it may become stuck to the inner pipe. I had something to do. In addition, there were cases in which the pressure within the inner pipe did not change for a long period of time, and the shape of the pipe did not change within a certain period of time, resulting in a significantly poor ability to freely remove scale. As a result, even if air is introduced from the end into the space between the inner and outer pipes, there is a large resistance and the air cannot smoothly reach the far end from the inlet, causing the problem that the inner pipe cannot be deformed as expected. Ta.

(Means for Solving the Problems) The present invention provides an improved composite pipe that solves the above-mentioned problems, and is characterized by a circular shape on the outside of a freely deformable inner pipe having a fluid transfer passage inside. Alternatively, an outer pipe having a fixed oval shape is provided, and a flexible pipe having a large number of pipe wall through holes is arranged in the space formed by the inner and outer pipes.

(Example) FIG. 1 shows a cross-sectional view A and a partial vertical cross-sectional view B of an example of a composite pipe according to the present invention. In the drawings, reference numeral 1 denotes a freely deformable inner pipe made of, for example, a polyethylene pipe with an oval cross section, or a hose without shape retention, such as a product jet hose, etc., which has a fluid transfer passage 3 for water, hot water, hot spring water, etc. inside. , 2 is an outer pipe with a fixed shape provided outside the freely deformable inner pipe 1, such as a metal pipe such as a stainless steel pipe, a steel pipe, an extruded aluminum pipe, or a plastic pipe such as a polyethylene pipe or a polyvinyl chloride pipe. It is composed of a pipe, and may be corrugated to improve flexibility.

A flexible pipe 5 having a large number of pipe wall through-holes 6 is arranged in the space 4 formed by the freely deformable inner pipe 1 and the fixed-shaped outer pipe 2. A plastic pipe such as polyethylene or polyvinyl chloride is generally used as the flexible pipe 5, and the pipe wall through-holes 6 are directed downward in order to function effectively and are arranged at regular intervals. is desirable. Moreover, a flexible metal pipe such as aluminum or lead pipe may be used instead of the plastic pipe.

In such a composite pipe, fluid is normally transferred at a constant pressure inside the inner pipe 1 which is free to deform, but the pressure of the fluid flowing through the fluid transfer passage 3 is changed under this constant pressure or as necessary. or stop the fluid transfer for a certain period of time to remove the liquid pressure, and introduce gas or the like from one end of the flexible pipe 5 and eject it from the pipe wall through-hole 6 to transform the inner pipe 1, which can be freely deformed. By applying the necessary pressure to the pipe 1, it is possible to deform the pipe 1 and prevent the adhesion and growth of scale.

In the above embodiment, when a metal pipe is used as the outer pipe 2 with a fixed shape, it is desirable to provide an anti-corrosion layer of polyethylene, polyvinyl chloride, etc. on the outer periphery, and when insulation properties are required, the outer pipe 2 A heat insulating layer is provided on the outer periphery of the

(Effect of the invention) According to the above-described composite pipe of the present invention, a flexible pipe having a large number of pipe wall through-holes is arranged in the space formed by the freely deformable inner pipe and the shape-fixed outer pipe, and The fluid pressure in the free inner pipe remains constant or preferably is reduced or removed, and gas is introduced into the flexible pipe and ejected from the pipe wall through-hole to create the required pressure in the space of the pipe. By rapidly and uniformly deforming the inner pipe in the longitudinal direction, it is effective to prevent scale adhesion and growth and to prevent pressure loss deterioration.

In addition, due to the presence of the outer pipe with a fixed outer shape, the composite pipe as a whole can have sufficient shape retention, making it easy to lay and install the pipe, and furthermore, it can be installed underground or vertically in buildings, etc. It also has the effect of making it possible.

[Brief explanation of the drawing]

FIG. 1 shows a cross-sectional view A and a partial vertical cross-sectional view B of an embodiment of a composite pipe according to the present invention, and FIG. 2 shows a cross-sectional view of an example of the composite pipe proposed earlier. 1... Inner pipe that can be freely deformed, 2... Outer pipe with fixed shape, 3... Fluid transfer passage, 4... Space section,
5... Flexible pipe, 6... Tube wall through hole.

Claims (1)

[Claims for Utility Model Registration] (1) An outer pipe with a fixed circular or oval shape is provided outside the deformable inner pipe that has a fluid transfer passage inside, and a large number of pipe walls are provided in the space formed by the inner and outer pipes. A composite pipe characterized in that a flexible pipe having a through hole is arranged. (2) The composite pipe according to claim 1, wherein the pipe wall through holes are at least directed downward and are provided at regular intervals in the longitudinal direction.