JPH0520637B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for laying multiple insulated pipes for use in district heating and cooling, etc., for efficiently laying them underground with a small amount of excavation.

[Prior art and problems]

In recent years, regional development including district heating and cooling has been actively carried out not only in urban areas but also in rural areas, but the piping construction is divided into above-ground piping methods in which piping is installed on structures above ground, and piping in common ditches or private trenches. Although buried piping methods have come to be adopted, most of them are directly buried underground, where factory-produced pipes and insulated pipes are directly buried underground, as shown in Figures 7 and 8. method is predominant.

The above-ground piping method has the advantage of being easy to change the route after installation, but it has problems in terms of aesthetics and ground space.The underground piping method, which uses a common trench or a dedicated trench, is superior in terms of equipment, but takes up a large area. The disadvantage is that the construction period and construction costs increase.

The most common direct underground burial method is economically superior, but requires increased strength of the casing pipe as it receives direct earth pressure or vehicle loads, and it is buried at regular intervals in an open trench, making it difficult to excavate. As the trench width increases, the amount of civil engineering work increases, and it is inefficient to bury as many service pipes as there are service pipes.

As a means to solve these shortcomings,
A perforated tube in which a filler having a plurality of holes in the tube axis direction is arranged inside the outer tube as shown in No. 97338 "Porous tube" has been proposed, but this porous tube is suitable for wiring multiple electric wires. In order to smoothly align the outer tubes when joining them, a rod-shaped body is implanted on one end surface, and a hole is provided on the other end surface to fit the rod-shaped body.From the viewpoint of strength and airtightness, The problem was that it was not suitable for cold and hot water piping, and it took time to bury it.

[Purpose and structure of the invention]

The present invention is a method for laying multiple conduits in order to solve the problems of the above-mentioned conventional technology, and was developed in particular to efficiently perform the work of burying insulated multiple conduits using cold and hot heat. Yes, the gist is that after a large-diameter outer pipe with a heat insulating material containing a plurality of small-diameter inner pipe through-holes is laid and joined in an cut-and-cut groove, the small-diameter inner pipe is inserted into the small-diameter inner through-holes. It is a method of laying multiple insulated pipes that are sequentially inserted and joined.

Furthermore, the heat insulating material to be placed inside the large-diameter outer tube of the present invention is foam-filled with urethane or styrene resin as a factory prefabricated material, and the small-diameter inner tube is a flexible tube made of resin that is easy to handle. Alternatively, the small-diameter inner pipe may be continuously formed and inserted at the installation site after the large-diameter outer pipe has been installed.

〔Example〕

Next, the embodiments of the present invention are shown in Figs.
This will be explained based on FIG.

First, a heat insulating material 2 made of urethane, styrene resin, or the like is filled inside the large diameter outer tube 1 at a factory. Inside the insulation material, there is a small diameter inner pipe 3 installed at the installation site.
A small diameter inner tube passage hole 4 for inserting the tube is formed in advance. To fill the heat insulating material 2, as shown in FIG. 4, the large-diameter outer tube 1 is blinded with plates 5 that sandwich the large-diameter outer tube 1, and a plurality of bolts 6 and nuts are inserted between the two plates. 7 to improve the sealing performance. Next, the core 8 for holding the through hole 4 for the small diameter inner tube 3 is supported and sealed by the plates 5 at both ends, and the injection hole 9 is insulated with urethane, styrene resin, etc. Fill material 2 with foam. Although urethane and styrene resin are used as examples of heat insulating materials, other heat insulating materials may be used as long as they have heat retaining performance and are easy to mold.

Figures 2 and 3 show the cross-sectional structure after the large diameter outer tube 1 is filled with the heat insulating material 2, and Figure 3 shows the reinforcing material used when the large diameter outer tube 1 requires further strength. The reinforcing member 10 is provided internally, either continuously or intermittently, before being filled with the heat insulating material 2, and by providing the reinforcing member 10 internally, it is also possible to reduce the wall thickness of the large diameter outer tube 1.

As shown in Fig. 1, the large-diameter outer pipe with insulation produced in the factory as described above is suspended by heavy machinery (not shown) or the like into an excavated trench at the installation site, and a plurality of small-diameter inner pipe through holes 4 are made. After aligning the centers and making them communicate, they are closely joined. The joining method differs depending on the material of the large diameter outer pipe 1. For steel pipes, butt welding, for cast iron pipes and synthetic resin pipes, mechanical joints are used, and for humid pipes, asbestos cement joints according to JISA-5315 are used. Any other joining method may be used as long as it maintains watertightness and has sufficient strength against external forces such as earthquakes.

After the large-diameter outer pipe containing a heat insulating material is laid and joined in a certain section in this way, the small-diameter inner pipe 3 is successively inserted into the small-diameter inner pipe passage hole 4 as shown in FIG. 5 to carry out construction.
What is shown in FIG. 6 is a folded bag-like sheet 11 impregnated with resin after the construction of the large-diameter outer pipe is completed, and is inverted by water pressure to form the small-diameter inner pipe 3 in the small-diameter inner pipe passage hole 4. This is an example of a method for inserting and constructing small-diameter inner pipes more efficiently.

〔Effect of the invention〕

In the present invention, since multiple insulated pipes are laid in the above-described steps, the amount of excavation is reduced and the construction period is shortened compared to the conventional direct underground burial method.

In addition, since multiple small diameter inner tubes are compactly housed within the large diameter outer tube at regular intervals, the strength against earth pressure is increased and the wall thickness of the large diameter outer tube can be made thinner and the material selection for the inner tube can be made freely. This also contributes to reducing material costs.

Furthermore, since it becomes possible to continuously form small-diameter inner pipes using bag-like sheets, as illustrated in FIG. 6, it is possible to significantly shorten the construction period.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing the state in which a large diameter outer pipe according to the present invention is laid in an excavated trench, Fig. 2, Fig. 3
The figure is a front view showing the cross-sectional structure after filling the large diameter outer pipe with heat insulating material, Figure 4 is a perspective view showing the device for filling the large diameter outer pipe with heat insulating material at the factory, and Figure 5 is A state diagram of inserting a small-diameter inner pipe into the small-diameter inner pipe passage hole of the large-diameter outer pipe after temporary construction; FIG. 6 is a schematic diagram of the work of continuously forming and inserting the small-diameter inner pipe after the construction of the large-diameter outer pipe is completed; FIGS. 7 and 8 are cross-sectional views of pipes showing an example of a conventional direct underground burial method. 1: Large diameter outer pipe, 2: Insulation material, 3: Small diameter inner pipe,
4: Small diameter inner pipe hole, 5: Plate, 6: Bolt,
7: Nut, 8: Core, 9: Injection hole, 10: Reinforcing member, 11: Bag-shaped sheet.

Claims (1)

[Scope of Claims] 1. A large diameter outer pipe in which a heat insulating material having a plurality of small diameter inner pipe through holes is laid and bonded inside the cut groove, and then a small diameter inner pipe is inserted into the small diameter inner through hole. A method of laying multiple insulated conduits characterized by sequentially inserting and joining pipes. 2. The method for installing multiple heat-insulating pipes according to claim 1, wherein the heat insulating material inside the large-diameter outer pipe is filled with urethane, styrene resin, or the like. 3. The method for laying multiple insulated pipe lines according to claim 1, wherein the inner pipe inserted into the small diameter inner pipe passage hole in the heat insulating material is a flexible pipe made of resin. 4. The method for laying multiple insulated pipes according to claim 1, wherein the inner pipe to be inserted into the small-diameter inner through-hole in the heat insulating material is formed continuously at the installation site after completion of laying the large-diameter outer pipe.