JPS605277Y2 - Heat exchanger - Google Patents

Description

[Detailed description of the invention] The purpose of this invention is to prevent fluids from mixing with each other and to improve heat transfer efficiency in a heat exchanger that conducts heat from one fluid to another. It is.

Generally, when trying to obtain a heat source using solar heat, it is easy and widely used to use hot water obtained from a heat collector for hot water supply, but in the Chubu region and north of Japan, in winter The collector may be destroyed by freezing of the water.

For this purpose, conventionally, as shown in Figure 1, the water circuit of the heat collector 1,
Separate the water circuit of the water heater 2, and connect the hose 4 and valve 5 with a pressurized cylinder or pressurized pump 3 to prevent it from freezing.
An antifreeze solution containing an antifreeze agent or the like is injected into the heat collector 1 and the heat exchanger 6 via the heat collector 1 and the heat exchanger 6.

That is, the heat collector 1 receives heat from the sun, and the valve A
, the valve 8 is opened, the antifreeze is circulated by the pump 9, and the water in the water heater 2 is heated by the heat exchanger 6.

Note that the expansion and contraction of the antifreeze is absorbed by the expansion tank 10.

Furthermore, FIGS. 2 and 3 are a front view and a sectional view of the water heater 2, and water supplied from the water supply port 11 is transferred to the outer surface of the heat exchanger 6 which is transferred to the tank 12 as described above. The water is heated by heat conduction and supplied as hot water indoors etc. from the hot water supply port 13.

Note that 14 is a drain port for draining water, and the heat exchanger 6 and tank 12 are protected against corrosion by externally powered cathodic protection, and 15 is an electrode thereof.

In the case of the above configuration, if the antifreeze flowing through the heat exchanger 6 gets mixed into the water inside the water heater 2, various problems will occur.

In such a case, the double-tube heat exchanger 6 described above is used.

That is, details of the heat exchanger 6 are shown in FIGS. 4 to 6, and the heat exchanger 6 is composed of an inner tube 16 and an outer tube 17.
is supported by an outer tube 17, and the outer tube 17 is fixed to a flange 18, which is fixed to the side surface of the tank 12.

Since the outside of the outer tube 17 is spiral-shaped, the inner tube 1
6 and the outer tube 17 is a continuous spiral passage 21.
is formed, and the outer tube 17 is cut outside the flange 18.

Therefore, if the inner tube 16 or the outer tube 17 corrodes and water enters between the inner tube 16 and the outer tube 17, the water will flow out of the tank 12 from the opening 17a through the spiral passage 21. It's starting to leak out.

In addition, the inner tube 16 and the outer tube 17 are combined through a close contact portion 19 and a spiral portion 20. In the close contact portion 19, the inner tube 1
6 and the outer tube 17 are in uniform contact with each other, the inner tube 16
The heat transfer from the tube to the outer tube 17 is good, so the thermal efficiency is good.

However, since the spiral part 20 has a hollow passage 21 inside, when cold water is supplied from the water supply port 11, moisture in the air condenses in the passage 21. This condensed water is caused by nitrogen and oxygen in the air. , since it contains carbon dioxide, the pH value shows acidic and corrosive properties.
The drawback was that it corroded from the sides.

The present invention eliminates these conventional drawbacks, and as an example thereof, as shown in FIG. 7, a spiral passage 21 is filled with a powdered anticorrosion substance 22.

This anti-corrosion substance 22 is a substance effective in preventing corrosion of metals, such as nitrite, phosphoric acid, chromate, molybdate, benzoate or silicate, so that condensation water can be protected from the inner pipe 16. In addition to preventing corrosion of the outer tube 17, the anti-corrosion substance 22 eliminates the cavity inside the passage 21, and since the anti-corrosion substance 22 has better thermal conductivity than air, the heat exchange efficiency of the heat exchanger 6 is improved. It gets expensive.

Furthermore, when the anticorrosion substance 22 is dissolved in water, its volume decreases compared to when it is dry. In other words, when it is in a solid state, it is in a powder state, but when it is dissolved in water, its volume decreases, so that it easily collects condensed water. The space for passage of fluid can be secured, and the original role of the passage 21 (even if the inner pipe 16 or the outer pipe 17 corrodes, the fluid is discharged to the outside of the water heater 2).

). As described above, according to the present invention, the liquid inside the inner tube does not mix with the liquid outside the outer tube, so it is safe, and the provision of anticorrosion material improves heat conduction between the inner tube and the outer tube. Therefore, the heat exchange efficiency becomes high.

[Brief explanation of the drawing]

Figure 1 shows the country of the system configuration of the heat exchanger that was developed earlier in the present invention, Figures 2 and 3 are a partially cutaway front view and side view of the heat exchanger, and Figures 4 and 5 are the same. FIG. 6 is an enlarged sectional view of section A in FIG. 5, and FIG. 7 is a sectional view of essential parts of a heat exchanger according to an embodiment of the present invention. . 16...Inner pipe, 17...Outer pipe, 21.
...Aisle, 22...Anti-corrosion substance.

Claims (1)

[Claims for Utility Model Registration] 1. A metal inner tube through which a fluid passes, and a metal outer tube whose outer surface is in contact with another fluid. A heat exchanger characterized in that an anticorrosion substance containing one or more of nitrite, phosphate, chromate, molybdate, and benzoate as a main component is interposed between the heat exchangers. 2 A spiral passage is provided between the inner tube and the outer tube,
The heat exchanger according to claim 1, characterized in that this passage is provided with an anticorrosive substance.