JPS5920255B2 - Cooling method for long buried objects - Google Patents

Description

[Detailed description of the invention] The present invention provides long underground objects such as underground cable lines,
This invention relates to a method of cooling by circulating a liquid that is easily vaporized as a refrigerant.

Conventionally, underground cables with many cables installed side by side have been used to increase the current carrying capacity, but because the cables are laid closely together, the temperature rise in this area is large.
Limits the allowable current of the cable.

For this reason, an indirect pipe cooling method is used, in which a cooling pipe is buried in the soil near the cable installation pipe, and water is passed through it to cool it through the soil, but the water is circulated using a pump. This makes maintenance and management troublesome, and the large temperature difference between the water inlet and outlet makes uniform cooling impossible.

In view of this, two or more cooling pipes are installed in parallel along long underground objects to be cooled, such as underground cable lines, and their tips are connected, and a condensing cooler is installed in the drawer at the base. In this method, the base of one pipe is connected to an electric heating means such as a heater, and the pipe is filled with a liquid that easily vaporizes, such as water, freon, or ammonia, as a refrigerant. The gaseous refrigerant at the base of one pipe is heated, and the refrigerant in the condensing cooler is transferred to the base of the other pipe, using the head difference of the refrigerant between the base of one pipe and the other pipe. Cooling methods using one pipe base and sequential circulation are already known.

That is, in Fig. 1, 1 indicates a cable buried underground, that is, a long buried object, and along this buried object 1, two cooling pipes 2 and 3 are installed in parallel.
(including, but not limited to) pipes 2 and 3.
The tips of the pipes 4 are connected to each other, and the drawers 5 and 6 at the base are connected to a condensing cooler 7, so that the refrigerant 8 such as Frene filled in the pipes 2 and 3 is cooled and the vaporized content is liquefied. be.

At this time, a heating part 9 having a band heater wrapped around one side of the base drawer part of the pipe, for example, the outer periphery of the drawer part 6, is provided to provide a temperature difference, that is, a head difference, between the refrigerant and the heating part 1 and the drawer part 5.
Therefore, the refrigerant in the drawer part 6 becomes lighter than the refrigerant in the drawer part 5, and the refrigerant in the drawer part 6 flows into the condensing cooler T, where the vaporized refrigerant is liquefied.

On the other hand, the refrigerant in the drawer part 5 flows downward due to the head difference, and then the liquefied refrigerant flows in, so the head difference becomes more and more narrow.Therefore, the refrigerant flows into the cooling pipes 2 and 3 in the direction of the arrow in the figure. It circulates, cools long buried objects, and repeats vaporization and liquefaction to efficiently cool them.

In the figure, 10 indicates cooling fins of the condensing cooler 7.

However, in this cooling method, a heating section 9 consisting of an electric heating means is used.
, the maintenance cost is high and the maintenance is complicated.

An object of the present invention is to reduce maintenance costs and simplify maintenance in a cooling method in which refrigerant is circulated using a refrigerant head difference.

FIG. 2 shows an embodiment of the present invention, and only the points different from FIG. 1 will be explained. In FIG.
A heat insulating layer 11 may be provided by wrapping a heat insulating material around the pipe, and a cooling fin 12 may be attached to the other pipe pull-out portion 5 for cooling to provide a head difference.In the latter case, after installing the heat insulating layer and cooling fins Since there is no need to take any detailed measures, maintenance and management become easier.

Note that even if the cooling fins 12 are omitted and only the heat insulating layer 11 is provided, a head difference sufficient to circulate the refrigerant will occur.

Next, as shown in Fig. 3, a 6KV plastic insulated cable is drawn into the multi-strip conduit as a long buried object, and two steel pipes with an inner diameter of 30m++φ are laid at the locations of Fig. A and the mouth. A condensing cooler was attached to the tip of the steel pipe, and a 20rtrm-thick foam insulation layer was provided on one side over 1m of the base of the steel pipe, and a 0.77rr? Using a finned tube with a surface area of It can be seen that the heat dissipation effect from the tube part is also quite good.

As explained above, according to the present invention, a plurality of cooling pipes are arranged in parallel along a long buried object to be cooled, such as an underground cable, and communicated at the tips, and a condensing cooler is installed at the drawer part of the base. When a long buried object is cooled by connecting and filling the inside with a refrigerant that easily vaporizes, a heat insulating layer is provided at the base of the pipe that leads the refrigerant from the pipe to the condensing cooler.

As a result, heat radiation from the pipe base is prevented, condensation of the refrigerant within the pipe base due to heat radiation is prevented, and the pipe base and the other pipe base that leads the refrigerant from the condensing cooler to the pipe are prevented. A temperature difference occurs between the two, and the long buried object to be cooled is cooled by circulating the refrigerant without using a pump.

Since the present invention does not use electrical heating means that require a power source and wiring, maintenance costs are low and maintenance is simple.

[Brief explanation of the drawing]

FIG. 1 is a side view of the prior art, FIG. 2 is a side view of the embodiment of the present invention, and FIG. 3 is a front view of the embodiment of the present invention. 1... Long buried object, 2, 3... Cooling pipe, 5, 6
... Base drawer of the cooling pipe, 7... Condensing cooler,
8... Refrigerant, 11... Heat insulation layer.

Claims (1)

[Claims] 1 Multiple cooling pipes are installed in parallel along a long buried object to be cooled, such as an underground cable track, and their tips are connected, and a condensing cooler is connected to the tip of the drawer at the base of the pipe. A method for cooling a long buried object by filling it with a refrigerant that easily evaporates, characterized in that a heat insulating layer is provided at the base of the pipe that leads the refrigerant from the pipe to the condensing cooler. Method.