JPS6350620Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention is a heat pipe corrosion protection device, particularly a heat pipe in a heat pipe type heat exchange device in which a liquid is used as at least one of the heating medium and the heated medium. This invention relates to anti-corrosion equipment.

Conventional technology and problems to be solved In a heat pipe type heat exchange device that uses a liquid as a heat medium, the evaporating part (heating part) or condensing part (heat radiation part) of the heat pipe remains in the liquid state all the time or for a long time. Since the heat pipes are in contact with each other, corrosion is likely to occur in the heat pipes at this contact portion.

In particular, for example, heat exchange equipment for road snow melting using heat pipes (so-called road heating equipment), which has been attracting attention recently, uses underground installations to circulate hot spring water, etc., as shown schematically in Figure 1. A plurality of heat pipes 1 are placed below the road surface 3 with the evaporation section 1a at one end inserted into the heat medium distribution pipe 2 of It is designed to melt snow on the road surface 3. Therefore, corrosion tends to occur near the evaporation part of the heat pipe 1, which is constantly in contact with corrosive liquids such as hot spring water. Of course, the heat pipe 1 for this purpose is itself made of a material with excellent corrosion resistance such as stainless steel, but it still suffers from pitting corrosion and interstitial corrosion in the highly corrosive environment described above. , occurrence of intergranular corrosion, etc. is unavoidable. When this kind of corrosion occurs, it is because the heat pipe is buried underground.
It is extremely difficult to replace or repair it, and if leakage of the working fluid occurs over time, it can lead to essential damage to the heat exchange device itself, and there is a significant instability factor in terms of durability. There was a problem.

This kind of problem is not limited to heat exchange equipment for road snow melting, but also to heat exchange equipment for waste heat recovery, which uses exhaust heat from boilers etc. to heat cold water with heat pipes and uses it in hot water supply systems. Similarly exists.

This invention was made to solve the above problems, and in a heat pipe type heat exchange device in which a liquid is used as at least one of the heating medium and the medium to be heated, the heat pipe is It is an object of the present invention to prevent early corrosion due to contact with liquid, and to improve the durability of the heat exchange device.

Means for Solving the Problems This invention provides a heat pipe type heat exchange device in which a liquid is used as at least one of the heating medium and the medium to be heated. is drawn by spinning, and a conductive mounting member is inserted into a through hole formed in the axial direction at the center of the tube end and fixed in electrical continuity with the heat pipe body. The above-mentioned problem can be solved by having a sacrificial anode piece made of a material having an electrode potential lower than that of the heat pipe body attached in an electrically conductive state.

Embodiments Hereinafter, the configuration of this invention will be explained in more detail based on illustrated embodiments.

FIG. 2 shows an embodiment in which this invention is applied to a road snow melting heat exchange device as shown in FIG.
Reference numerals 20 and 21 are heating medium flow pipes, and 30 is a connecting T-shaped pipe for interconnecting the flow pipes 20 and 21 and the heat pipe main body 10. The heat pipe main body 10 has an evaporation section 11 that is connected to a heating medium flow path 22.
The flange 12 is inserted from the side into the T-shaped pipe 30 through a connecting pipe 32 with a flange 31 so as to face the T-shaped pipe 30, and the flange 12 formed on the outer surface of the intermediate part in the longitudinal direction is connected to the opposing flange 31. By fastening with bolts and nuts 33 through packing, a liquid-tight connection is achieved.
Note that 13 indicates a condensing part of the heat pipe main body.

In Fig. 2 and Fig. 3, 50 is a sacrificial anode piece. This sacrificial anode piece 50 is for forming a potential difference with the heat pipe body 10 to pass an anticorrosive current and prevent corrosion of the heat pipe body 10. Therefore, it is made of a material with a lower electrode potential than the heat pipe body 10. For example,
When the heat pipe body 10 is made of austenitic stainless steel, the sacrificial anode piece 5
As the material for 0, a material having a lower electrode potential than that of 0, such as an aluminum-zinc alloy, an aluminum-manganese alloy, mild steel, a ferritic stainless steel, a zinc alloy, or a magnesium alloy, is preferably selected and used.

The sacrificial anode piece 50 is attached as follows. That is, the evaporation section 1 of the heat pipe main body 10
The end of 1 is drawn into a hemispherical shape by spinning for sealing. The tube end of the heat pipe main body must be completely sealed, but it is difficult to achieve complete sealing only by spinning because of the oxide film present on the tube end surface. For this reason, the final closure is generally performed by cutting out the metal base at the center with a drill 70 and removing the oxide film, as shown in Figure 4, and then welding. It is true. Therefore, by using the through hole 14 created in the axial direction at the center of the tube end by cutting with the drill 70,
A conductive bolt 40 as a mounting member is screwed into this through hole 14. And this bolt 40
A welded portion 60 is formed at the boundary between the heat pipe body 10 and the heat pipe body surface in order to ensure adhesion between the two and sealing of the end of the heat pipe body 10. The sacrificial anode piece 50 is attached to the tip of the bolt 40 in an electrically conductive state. By adopting such an attachment structure for the sacrificial anode piece 50, the attachment of the sacrificial anode piece 50 can be incorporated into the process of sealing the end of the heat pipe main body and can be performed simultaneously, thereby simplifying the manufacturing process. be able to. Note that the bolt 40 is made of a nobler material than the sacrificial anode piece 50.

In the apparatus according to the above embodiment, the evaporator section 11 of the heat pipe main body 10 is heated by coming into contact with a heating medium such as hot spring water flowing through the flow pipes 20 and 21, but does not face the flow path of the heating medium. An anticorrosion current flows between the heat pipe body 10 and the sacrificial anode piece 50 due to the potential difference between them, and the sacrificial anode piece 50 corrodes before the contact portion of the heat pipe body 10 with the heat medium. Therefore, corrosion of the heat pipe main body 10 is reliably prevented, and the useful life of the heat exchange device as a whole is thereby increased.

Of course, the heating medium is not limited to hot spring water.
It may also be a liquid such as freshwater or seawater. Further, in the embodiment, a case is shown in which the heating medium is a liquid, but as in the case of the heat exchange device for exhaust heat recovery described above, the medium to be heated in contact with the condensing part of the heat pipe body is a liquid such as cold water. This invention can be similarly applied to such cases. The same applies to the case where both the heating medium and the medium to be heated are liquids.

Effects of the invention As explained above, this invention provides a heat pipe type heat exchange device in which a liquid is used as at least one of the heating medium and the heated medium. Since the sacrificial anode piece made of a material of Early corrosion of the pipe body can be reliably prevented.
Therefore, the life of the heat pipe can be greatly extended,
Furthermore, especially when applied to road snow melting heat exchange equipment or heat exchange equipment for waste heat recovery, where heat pipes are difficult to replace or repair, it is advantageous in that the required durability can be guaranteed, and the product can be used for a long time. It becomes possible to provide highly durable heat exchange equipment that can withstand long-term practical use.

Further, the tube end of the heat pipe main body is drawn by spinning, and a conductive mounting member is inserted into a through hole formed in the axial direction at the center of the tube end and fixed in an electrically conductive state. Since the sacrificial anode piece is attached to this mounting member in an electrically conductive state, it is a metal that is normally used for complete sealing when closing the tube end of the heat pipe body by spinning. A through hole created in the axial direction at the center of the tube end by cutting out to remove the membrane can be used as a hole for attaching the attachment member. As a result, the step of attaching the sacrificial anode piece can be carried out by incorporating it into the process of sealing the end of the heat pipe, and the manufacturing process can be simplified.

[Brief explanation of the drawing]

Fig. 1 is a front cross-sectional view showing a schematic configuration of a heat pipe type heat exchange device for road snow melting as an example to which this invention is applied, and Fig. 2 is a main part of the above device showing an embodiment of this invention. Part cutaway plan view,
FIG. 3 is an enlarged cross-sectional view showing the sacrificial anode piece attachment portion at the end of the heat pipe body, and FIG. 4 is a cross-sectional view showing the state of the drilling process during sealing of the tube end of the heat pipe body. 10... heat pipe body, 11... evaporation section,
13... Condensation part, 20, 21... Heating medium distribution pipe, 40... Mounting bolt, 50... Sacrificial anode piece, 60... Welding part.

Claims (1)

[Scope of utility model registration request] In a heat pipe type heat exchange device in which a liquid is used as at least one of the heating medium and the medium to be heated, the tube end of the heat pipe body that comes into contact with the liquid is drawn by spinning, and the center of the tube end is drawn by spinning. A conductive mounting member is inserted into a through hole formed in the axial direction in the heat pipe body, and is fixed in electrical continuity with the heat pipe body. 1. A heat pipe corrosion prevention device in a heat pipe type heat exchange device, characterized in that a sacrificial anode piece is attached in an electrically conductive state.