JPH0452327B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a traffic sign that prevents snow and frost from accumulating on the traffic sign, maintains a clear sign surface, and facilitates construction and maintenance work.

During the winter, in snowy or cold regions, traffic signs installed on roads etc. will have snow or frost build up on their sign surfaces, making the sign surface extremely unclear and making it difficult to use as a traffic sign. There was a serious problem in that the system was not able to fully demonstrate its functions, leading to traffic accidents.

One possible way to solve this problem is to use commercial power to heat the sign surface of the traffic sign with an electric heater, etc., but traffic signs, which are often installed on the side of the road, can be used to prevent traffic accidents. It has not been put into practical use for several reasons, including the risk of causing unexpected short circuits and electric shocks, and the need for maintenance work after installation.

Furthermore, the concept of heating the sign surface by utilizing geothermal heat using a heat pipe is disclosed in Japanese Patent Publication No. 58-5429. For example, as shown in FIG. 1, the condensing side part 3 of the heat pipe 2 buried underground is located in an enlarged or multi-branched structure on the back side of the sign surface 1 of the traffic sign. The outer surface of 3 is the sign surface 1
It is also used as a heat pipe 2.
The working fluid 4 inside is heated by geothermal heat and evaporates,
Heat is transferred to the condensing side 3 on the back side of the sign surface 1, and the sign surface 1
It is used to heat the

In this method, the hydraulic fluid 4 that has absorbed geothermal heat directly heats the sign surface 1, which is preferable in terms of high heat transfer, but it also heats the sign surface 1 and prevents snow and frost formation. For this purpose, it is sufficient if the sign surface temperature is around 5 degrees Celsius, and a very high heat transfer is not necessary. Furthermore, since the condensing side portion 3 of the heat pipe 2 and the sign surface 1 are integrated, it is impossible to adjust the angle or replace the sign surface 1 after installation.
That is, at the production stage, the dimensions and shape of the heat pipe 2 must be determined according to the conditions of the installation location, and the condensing side part 3 of the heat pipe 2 must be enlarged or processed into a multi-branched structure. After that, it is necessary to evacuate the inside of the heat pipe 2, resulting in extremely low productivity. Furthermore, even when the sign surface 1 is replaced, there are drawbacks such as the need to replace the entire traffic sign including the heat pipe 2, and this has not yet been put to practical use.

Another method is to install the condensing side part of a heat pipe on the back surface of a curved mirror (sign surface) via a heat transfer conductor. However, the contact area between the cylindrical heat pipe and the planar heat transfer conductor is extremely small, and an air layer is likely to form between the heat pipe and the heat transfer conductor, increasing thermal resistance and reducing thermal efficiency. Furthermore, if the shape of the heat pipe is processed to match the angle of the sign surface, or if a good heat transfer conductor with a good heat transfer rate is used, there are problems such as an increase in cost.

Therefore, the purpose of the present invention is to eliminate all of the above-mentioned drawbacks and to create a heat pipe section that pumps geothermal heat and a heating section that heats the sign surface using different heat transfer systems using heat exchangers, thereby achieving sufficient snow accumulation and adhesion. To provide a practical traffic sign that prevents frost and has extremely high productivity and construction workability.

Therefore, in order to achieve the above object, the traffic sign of the present invention pumps geothermal heat using a heat pipe,
In this traffic sign whose sign surface is heated by geothermal heat, a heat exchanger filled with a heat medium is installed in the heat dissipation part of the heat pipe, and a heating room that receives heat transfer from the heat exchanger is marked. It is characterized in that it is provided on the back side of the surface, and the heat exchanger and heating chamber are removably connected.

Hereinafter, the present invention will be explained in detail based on the embodiment shown in FIG.

The traffic signs indicated by 5 as a whole include instruction signs, regulation signs, curved mirrors, delineators, and various traffic signals depending on the installation location and purpose, and each sign is formed on the sign surface 6.

First, heat pipe 7 that effectively pumps geothermal heat.
A pump having a certain size and filled with an appropriate amount of a working fluid 8 such as ammonia and evacuated is used.
The heat pipe 7 can be effectively installed after boring to a depth (2 m to 10 m) that can pump geothermal heat.
Temporarily install the heat pipe 7, fix it with cracked stones and concrete, and install it. In order to prevent heat loss of the absorbed geothermal heat, the heat pipe 7 is inserted into the signpost 9 while being covered with a heat insulating material such as urethane foam from about 1 m underground to a heat exchanger 13 to be described later. .

A bag-shaped body 10' made of polyethylene or the like is attached to the back side of the sign surface 6 so as to form a heating chamber 10 extending over the area requiring heating.
An opening/closing opening 11 for heat medium injection is provided at the top of the holder, and heat medium circulation ports 12a and 12b are provided at the upper and lower parts, respectively. Although not shown, the portion of the bag-shaped body 10' exposed to the outside air is covered with a heat insulating material.

13 is a heat exchanger, which is the heat pipe 7 mentioned above.
A heat transfer system that transfers the geothermal heat pumped up by the heat absorption section 15 of the heat pipe 7 to the heat dissipation section 14 of the heat pipe 7 using the working fluid 8, and a heat transfer system that transfers the heat to the heating chamber 10 that heats the sign surface 6. It performs heat exchange and is attached to the signpost 9 at a lower position than the heating chamber 10. The heat exchanger 13 is provided with at least one heat pipe connection port 16,
With the heat dissipation section 14 of the heat pipe 7 positioned within the heat exchanger 13, the connection port 16 is sealed with a seal ring or the like. Heat medium circulation ports 12a and 12b of the heating chamber 10 are provided at the upper and lower portions of the heat exchanger 13.
Heating medium circulation ports 17a, 17b are provided corresponding to each of the upper heating medium circulation ports 17a, 12a and the lower heating medium circulation ports 17b, 12b are removably connected with flexible heat insulating hoses 18a, 18b. By removing the flexible heat insulating hoses 18a and 18b, the sign surface 6 to which the heating chamber 10 is attached can be removed.
can be removed from the heat exchanger 13.
Heat exchanger 13, flexible insulation hoses 18a, 18b
The inside of the sign surface heating heat transfer system consisting of the heating chamber 10 is filled with a heating medium 19 through the heating medium injection opening/closing opening 11 of the heating chamber 10, and is degassed. The sign surface 6 to which the heating chamber 10 is attached is fixed to the sign post 9 using fastening fittings 20 so that the sign surface 6 can be adjusted vertically and horizontally as desired.

Next, the operation of the heat transfer system of the present invention will be explained. First, in the geothermal absorption heat transfer system using the heat pipe 7, the working fluid 8 of the heat pipe 7 is heated and vaporized by geothermal heat in the heat absorption part 15, and then converted into a heat medium 19 in the heat radiation part 14 located in the heat exchanger 13. The geothermal pumping cycle of transferring heat, liquefying it, and lowering it to the heat absorption section 15 is repeated.

Next, in the sign surface heating heat transfer system, the heat medium 19 whose temperature has increased by the heat radiating part 14 of the heat pipe 7 in the heat exchanger 13 causes convection due to the difference in specific gravity, and 13 through the heat medium circulation port 17a and the heat medium circulation port 12a of the heating room 10, and thereby the sign surface 6 is heated. Since the sign surface heating heat transfer system is a closed system filled with the heat medium 19, natural circulation is efficiently performed by thermosiphon action. Heating room 1 where the temperature is lowered by heating the sign surface 6
The heat medium 19 inside 0 is the heat medium circulation port 1 of the heating chamber 10.
2b to the heat exchanger 13 via the flexible heat insulating hose 18b and the heat medium circulation port 17b. That is, heat exchanger 13 - heat medium 19 temperature rise - flexible insulated hose 18a - heating chamber 10 - sign surface 6 heating -
Heat medium 19 temperature drop - Flexible insulation hose 18b -
A heat exchanger 13 performs a heat transfer cycle.

As mentioned above, since the heat dissipation part 14 of the heat pipe 7 is located inside the heat exchanger 13, heat loss is extremely small, the sign surface heating heat transfer system is filled with the heat medium 19, and the heating chamber 10 is used for heat exchange. Since it is located higher than the vessel 13, heat is always evenly transferred to the heating chamber 10. Note that it is possible to attach a plurality of heat exchangers 13 to one heat pipe 7 to heat a plurality of sign surfaces 6. When installing the heat exchanger 13 in the middle of the heat pipe 7, it is sufficient to simply pass the heat pipe 7 through the heat exchanger 13, and the heat pipe 7 can be processed into a complicated shape or a wick that utilizes capillary action can be installed. It is not necessary, and the sign surface heating heat transfer system is simply constructed of flexible and elastic members, resulting in high productivity and workability.

As described above, according to the traffic sign of the present invention, the sign surface heating heat transfer system is filled with a heat medium and degassed, so heat loss in the heat exchanger is kept extremely low and a good heat transfer coefficient is achieved. allows natural circulation to occur evenly,
This is a practical traffic sign that can prevent snow and frost from accumulating by heating the sign surface.

In addition, if installed with multiple heat exchangers, it can be used for traffic signs with multiple sign surfaces, and the heat pipes used at the same time only need to be of a fixed size and shape.
It has excellent versatility and productivity because there is no need to prepare heat pipes of different sizes and shapes to match the sign surface. Furthermore, the sign surface can be replaced independently of the heat pipe, which has excellent practical benefits in terms of economy and ease of work.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a traffic sign using a conventional heat pipe. FIG. 2 is a sectional view of the traffic sign of the present invention. 6...Sign surface, 7...Heat pipe, 10...
Heating chamber, 13... Heat exchanger, 18a, 18b...
Flexible heat insulating hose, 19... heat medium.

Claims (1)

[Claims] 1. In a traffic sign in which geothermal heat is pumped up by a heat pipe and the sign surface is heated by this geothermal heat, a heat exchanger filled with a heat medium is provided in the heat dissipation part of the heat pipe, and the heat exchanger is heated. A traffic sign characterized in that a heating chamber for receiving heat transfer is provided on the back side of the sign surface, and the heat exchanger and heating chamber are removably connected.