JPH086295B2 - Construction method of heat pipe in the ground - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for attaching a heat pipe for extracting geothermal heat and heat contained in groundwater to the ground.

Conventional technology For example, when the heat of groundwater is used to remove snow from a road, conventionally, groundwater was generally pumped and sprayed directly onto the road. Maintenance work requires labor, and there is a risk that the ground level will drop due to a drop in groundwater level.

In order to eliminate such inconvenience, it has been conventionally considered that a heat pipe is buried between the surface of the ground and the groundwater level to directly melt the snow on the surface of the ground by the heat of the groundwater. In other words, the heat pipe evaporates the working fluid inside due to heat input, and the vapor flows to the low temperature side and then radiates heat to condense and liquefy, so the heat pipe transports a large amount of heat without the need for external power. Therefore, it is possible to remove snow from the road with simple equipment and without requiring special maintenance. In order to perform such snow removal with a heat pipe, it is necessary to first bury the heat pipe to the groundwater level, but since there has been no method specifically developed as a vertical laying method for the heat pipe, In burying it in the actual situation, it is inevitable that the method of excavating vertical holes used in the field of civil engineering and construction will be diverted.

Problems to be Solved by the Invention However, as a method of excavating a vertical hole, a metal casing having a drilling blade at its tip is struck to the surface of the earth and rotated, and at the same time, water is pressurized and injected into the metal casing, and then the metal casing is sequentially subjected to other operations. There is a known method of excavating a vertical hole by extending the metal casing, but since the heat pipe is more fragile than the one to be buried in the field of civil engineering and construction, protection of the heat pipe when removing the metal casing is known. Therefore, there is a problem that difficult work is forced, resulting in a longer construction period and higher cost.

In order to eliminate such inconvenience, it is conceivable to bury the metal casing, but since the metal casing is an excavator and is expensive, there is a problem that the construction cost becomes extremely high.

Furthermore, it is possible to insert the heat pipe into the vertical hole after removing the metal casing, but in the case of soft ground, the vertical hole that was excavated at the same time when the metal casing is extracted will collapse, so after inserting the heat pipe, the metal casing There was a problem that it had to be removed or buried in the metal casing.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a method capable of safely and easily laying a heat pipe in the ground.

Means for Solving the Problems In order to achieve the above object, the present invention is to form a vertical hole by excavating while pushing into the ground of a cylindrical metal casing, and then to make a synthetic resin inside the metal casing. Insert a pipe made of metal, then remove the metal casing and temporarily hold it with a synthetic resin pipe, and then insert a flexible heat pipe inside the synthetic resin pipe and the synthetic resin pipe. This is a method characterized by sampling.

Further, according to the present invention, a thin film may be provided in advance on the tip of the synthetic resin pipe in order to avoid the difficulty of inserting the heat pipe due to the inflow of groundwater into the synthetic resin pipe.

Further, according to the present invention, the thin film is pierced by the tip of the heat pipe, so that the groundwater as a heat source can flow into the periphery of the heat pipe.

Function In the present invention, the metal casing mainly functions for excavation of the vertical hole, while the temporary earth retaining for inserting the heat pipe functions as the synthetic resin pipe, and therefore the heat pipe is buried in the ground. When inserted in the excavated vertical hole, there is no metal casing and only the synthetic resin pipe exists.Therefore, when removing the synthetic resin pipe for earth retaining, the pipe interferes with the heat pipe. Even if the heat pipe is not damaged, the heat pipe can be easily laid vertically vertically in the ground.

EXAMPLES Next, the present invention will be described based on examples.

1 (A) to 1 (D) are explanatory views showing a construction process according to the method of the present invention. In the method of the present invention, the pit 1 is first excavated. That is, as shown in FIG. 1 (A), a cylindrical metal casing 2 having an excavating blade at the lower end peripheral portion thereof.
Is pushed against the surface of the earth and rotated, and at the same time, high-pressure water 3 is injected into the inside of the metal casing 2 to cut down and discharge the earth and sand, and as the metal casing 2 sinks, another metal casing 2 is added to the upper side. By welding and performing such work continuously, vertical hole 1 of required depth
To drill. Then, as shown in FIG. 1 (B), a flexible synthetic resin pipe 4 is inserted inside the metal casing 2. Here, the synthetic resin pipe 4 is for temporary earth retaining, a polyethylene pipe can be used, and the tip of the insertion side is sealed with a thin film 5 such as a synthetic resin sheet to prevent inflow of groundwater. It is preferable to keep. After inserting the synthetic resin pipe 4, the metal casing 2 is pulled out. In that case, the surrounding soil may collapse, but since the synthetic resin pipe 4 acts as a soil retainer, the vertical hole 1 is maintained. After the metal casing 2 is pulled out, as shown in FIG. 1 (C), a flexible heat pipe 6 is inserted inside the synthetic resin pipe 4. Here, as the heat pipe 6, a corrugated pipe (corrugated pipe) which is provided with flexibility by using it as a container can be used. Further, if a thin film is attached to the insertion-side end of the synthetic resin pipe 4, there is no inflow of groundwater into the interior thereof, so that the heat pipe 6 can be easily inserted. After inserting the heat pipe 6, the synthetic resin pipe 4 is removed. In that case, since the synthetic resin pipe 4 and the heat pipe 6 are both flexible, it is easy to avoid interference between them, and even if they interfere, the hardness of the synthetic resin pipe 4 Since the heat resistance is low, damage to the heat pipe 6 can be prevented. The thin film 5 at the tip of the synthetic resin pipe 4 is pulled out.
Is pierced by the tip of the heat pipe 6. First
FIG. 3D shows a state after the synthetic resin pipe 4 is pulled out.

In the above description, the case where the heat pipe is laid vertically has been described as an example, but the present invention is not limited to the above embodiment, and is also applied to the case where the heat pipe is laid diagonally. can do.

Effects of the Invention As described above, in the method of the present invention, after excavating the vertical hole using the metal casing, the metal casing is extracted in the state where temporary earth retaining is performed by the synthetic resin pipe, and the synthetic resin is used. Since the synthetic resin pipe is pulled out after inserting the heat pipe into the manufactured pipe, there is no risk of damaging the heat pipe, and therefore no special means for protecting the heat pipe is required. Combined with the flexibility of both pipes, vertical installation of the heat pipe can be easily performed. Also, if the tip of the synthetic resin pipe on the insertion side is sealed with a thin film, groundwater will not flow into the synthetic resin pipe prior to insertion of the heat pipe, so buoyancy will be increased when the heat pipe is inserted. It does not work, and therefore also in this respect it is easy to insert the heat pipe into the vertical hole.

[Brief description of drawings]

1 (A) to (D) are explanatory views showing a process of vertically laying a heat pipe according to the method of the present invention. 1 ... Vertical hole, 2 ... Metal casing, 4 ... Synthetic resin pipe, 5 ... Thin film, 6 ... Heat pipe.

Front page continuation (72) Inventor Koichi Masuko 1-5-1, Kiba, Koto-ku, Tokyo Fujikura Electric Line Co., Ltd. (72) Inventor Shinichi Sugihara 1-1-5, Kiba, Koto-ku, Tokyo Fujikura Electric Line Co., Ltd. In the company

Claims (3)

[Claims] 1. A cylindrical metal casing is pushed into the ground for excavation to form a vertical hole, a synthetic resin pipe is inserted inside the metal casing, and then the metal casing is removed to obtain a synthetic resin. A method for laying a heat pipe in the ground, wherein temporary earth retaining is performed with a pipe made of plastic, and then a flexible heat pipe is inserted inside the synthetic resin pipe and the synthetic resin pipe is removed. . 2. The method for laying a heat pipe in the ground according to claim 1, wherein the synthetic resin pipe has an insertion-side end sealed in advance with a thin film. 3. The method for laying a heat pipe in the ground according to claim 2, wherein the thin film is pierced by the tip of the heat pipe inserted inside the synthetic resin pipe.