JPS6116752Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a flexible pipe in which a cable is installed, cooling water is allowed to flow through the pipe to cool the cable, and the pipe is installed in a snake shape together with the cable.

As a means to dramatically increase cable power transmission capacity, a pipe is laid inside a tunnel, and after the cable is drawn inside the pipe, cooling water is forced to cool the cable inside the pipe, which further increases the temperature of the cable. One way to reduce the tendency of cables to extend out from pipes is to make the pipes flexible and lay the pipes and cables in a snake shape.

To explain this method with reference to drawings,
The pipe was made as straight as possible so as not to apply local force or friction to the pipe 1, and in this state, the cable 2 was drawn in (see Figure 1). After the cable 2 was drawn in, the pipe 1 was placed at a predetermined interval. The pipe 1 is placed on a plurality of support stands (not shown), and the pipe 1 and the cable 2 are bent in a predetermined manner by pressing down from the upper side of the pipe 1 with a jig and applying lateral pressure at the middle part of the support stands in front and back relationship. By sequentially repeating this operation in the longitudinal direction of the pipe 1, a snake-shaped curl is achieved. Ideally, this snake state should be such that the snake shape of pipe 1 and the snake shape of cable 2 match as shown in Figure 2, but in actual work,
The state will be as shown in FIG. Looking at this formation process, at the initial stage when the jig starts applying lateral pressure to the pipe 1, the pipe 1, which has a larger diameter than the cable 2, is deformed and the cable 2 is not deformed, and the deformed pipe 1 is the cable 2. After contacting the upper surface, a bending force is applied to the cable 1 for the first time by continuing to apply lateral pressure, and the pipe 1 and the cable 2 try to bend together.

However, this bending is achieved by moving the pipe 1 and the cable 2 in the axial direction, but since the Young's modulus of the more flexible pipe 1 and the rigid cable 2 with a conductor are different, the pipe 1 is more flexible than the cable 2. It moves by more than 1 to make the snake shape larger.

In reality, if the cable 2 has even a slight snake shape, the snake shape can be enlarged as the temperature rises and the extension of the cable 2 from the pipe 1 can be suppressed, so there is no practical problem.
There was one problem that made the work of creating such a snake shape difficult.

In other words, when performing snake-shaped curling work,
As mentioned above, pipe 1 and cable 2 differ in the amount of axial movement associated with bending, so it is necessary to create slippage between them. It is necessary to apply an external force _F1 that is sufficient to overcome the resistance force against the slip between Cable 2 and Pipe 1. However, if this simply uses Pipe 1 to accommodate Cable 2, it will cause relative slip between Cable 2 and Pipe 1. If the length of the cable 2 housed in the pipe 1 is large and the weight of the cable is large, the above F ₁ will exceed the force F ₂ that deforms the cable. This sometimes made it impossible to implement.

In order to reduce the resistance to slippage, it is possible to apply the same lubricant as when running the cable, but when the pipe is filled with water and circulated after the cable installation is completed, the lubricant is added to the circulation system. It adheres and causes problems such as clogging, corrosion, and melting.

Additionally, when the warm cooling water returns to the cooling system, if the specific gravity of the lubricating oil is lower than that of water, the lubricating oil will float on the surface, preventing the water from evaporating and reducing the cooling effect of the water due to evaporation. . Furthermore, it takes a lot of effort to apply lubricant inside the pipe after the pipe is laid and before the cable starts being pulled in, and it is also difficult to apply the lubricant uniformly.

Therefore, the purpose of the present invention is to solve the above-mentioned drawbacks of the prior art, and to provide a pipe for cable water cooling, which allows cables to be laid directly on water-cooled lines and can be easily twisted into a snake shape, and which does not impede the cooling effect. Our goal is to provide the following.

The cable water cooling pipe of the present invention for achieving the above object is flexible, and the inner surface is coated with silicone oil having a specific gravity of more than 1.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

A rubber hose (inner diameter 200 mm) with a reinforcing agent woven into the intermediate layer was used as the flexible pipe 1, and DC-550 (Dow Corning) in methyl phenyl silicone oil was used as a silicone oil with a specific gravity greater than 1 on the inner surface. This was applied using a commercially available product (trade name of Co., Ltd.).

In this way, the inner surface of the pipe 1 is coated with silicone oil having a specific gravity of more than 1, and as shown in FIG.
I tried pulling in cable 2 (outer diameter 100mm) with a PVC anti-corrosion layer, but the friction coefficient at that time was 0.05 ~
0.1, using a cable with the same PVC corrosion protection layer, the coefficient of friction for untreated pipes is 0.5 to 0.6, the coefficient of friction for pipes thoroughly wetted with water is 0.4 to 0.6, and the coefficient of friction for conventional water-soluble lubricants is 0.5 to 0.6. Compared to the friction coefficient of 0.4 to 0.5 in pipes coated with
It was found that the reduction was between 1/5 and 1/10.

Therefore, according to the pipe of the present invention, the frictional force when pulling in the cable can be sufficiently reduced, making it possible to easily carry out the cable installation work.

In the pipe 1 with the cable 2 installed as described above, the pipe 2 is mounted on support stands at regular intervals, and lateral pressure is applied from the outside of the front and rear intermediate parts of the support stand to create a snake-like curl. ,
As shown in FIG. 3, the snake shape of the cable 2 has a smaller amplitude than the snake shape of the pipe 1.

If there is a difference in the snake shape of the pipe 1 and the cable 2 as described above, axial slippage occurs between the two during bending of the snake shape.
At that time, the external force F ₁ that is sufficient to overcome the resistance force against the slip between the cable 2 and the pipe 1 can be reduced to at least 1/5 compared to the case of an untreated pipe, making it easier and safer to snake. This allows you to work on shaping the shape.

I tried flowing cooling water into the pipe 1 where the cable 2 was installed as described above, but the applied silicone oil did not form an oil film on the upper surface of the cooling water, and the cooling water circulation system No problems such as clogging or corrosion occurred.

Furthermore, in the pipe 1 coated with the silicone oil described above, there was no deterioration in pipe performance due to the silicone oil. If a flexible tube made of rubber or plastic is used as a pipe and ordinary lubricant is applied to it, the lubricant will soak the rubber or plastic and deteriorate the performance of the pipe, but this invention prevents such deterioration of pipe performance. It is also excellent in that it does

As explained above, according to the cable water cooling pipe of the present invention, by using silicone oil with a specific gravity of more than 1 as a lubricant and applying it to the inner surface of the flexible pipe, the cable can be drawn in easily. In addition, it facilitates the work of creating a snake-like shape on the cable, and it also provides an excellent cooling effect due to the flow of cooling water, so the practical effects are enormous.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing a state when the cable is pulled in, FIG. 2 is an explanatory diagram showing an ideal snake-shaped state, and FIG. 3 is an explanatory diagram showing an actual snake-shaped state. 1: pipe, 2: cable.

Claims (1)

[Scope of utility model registration request] In a flexible pipe that has a cable inside and a space for cooling water to flow between the cable and the cable, and is formed in a snake shape together with the cable, a silicone oil with a specific gravity greater than 1 is applied to the inner surface of the pipe. A cable water cooling pipe characterized by being coated with.