JPH0222858B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a solar water heater provided with cathodic protection.

Conventional Structure and Problems In recent years, solar water heaters oxidize the heat pipe heat dissipation section at the inner bottom of the hot water storage tank depending on the quality of the supplied water. In other words, heat pipes are generally made of copper or copper alloy, which has high thermal conductivity, but this can also cause oxidation, or the generation of blue water, and although it is advantageous from a performance standpoint, it has the disadvantage of However, there may be disadvantages in terms of use. The difficulty of the conventional anti-corrosion measures is that a large number of heat pipe heat dissipating parts are exposed in the hot water storage tank, and anti-corrosion measures must be applied to each of them, leaving no decisive technical solution. Examples of countermeasures include adjusting the overall water quality with water treatment agents and covering the surface of the heat pipe heat dissipation section with another non-metallic coating, but the former results in high equipment costs, while the latter This has caused problems such as a decrease in heat exchange efficiency.

Purpose of the Invention In view of the above-mentioned problems, the present invention has been developed by arranging a cathodic protection electrode opposite to a heat dissipation part of a heat pipe with an electrically nonconducting wall in between, and passing a corrosion protection current.
To provide a solar water heater that does not oxidize the heat radiation part of a heat pipe and therefore does not generate green water.

Structure of the Invention In order to achieve this object, the solar water heater of the present invention is provided with a hot water storage tank in which a heat dissipating part of a heat pipe is disposed, and a cathodic protection electrode fixed to the bottom of the hot water storage tank. A wall is disposed between the heat dissipation section of the heat pipe and the cathodic protection electrode, and with this structure, a corrosion protection current is applied almost equally to each part of the object to be protected, that is, the heat dissipation section of the heat pipe. It protects solar water heaters from corrosion.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIGS. 1 and 2 show the arrangement of cathodic protection electrodes of a solar water heater in an embodiment of the present invention. 1 shows a heat pipe with a medium sealed inside, 1-a is a heat collecting part, 1-b
indicates the heat dissipation part. 2 are heat pipes 1 in each column
A heat collecting fin is shown which is fitted across the heat collecting part 1-a. 3 indicates a hot water storage tank made of resin, which includes a hot water intake port 4, a water supply port 6 having a ball tap 5, and a water overflow port 7.
are provided for each. 8 shows a cathodic protection electrode fixed at a low position on the wall of the hot water storage tank 3, and a corrosion protection power source 9
Connect to the pole of 10 indicates an electrically nonconductive wall;
Cathodic protection electrode 8 and heat dissipation part 1- of heat pipe 1
The heat dissipation part 1- of each heat pipe 1 is arranged between
The shape is such that the anti-corrosion current i to b can be made almost uniform. In other words, the distances between the cathodic protection electrode 8 and the heat radiating portion 1-b of each heat pipe 1 are made almost the same, and the water resistance of each can be made the same. Hot water tank 3
If it is made of resin, the electrically nonconductive wall 10 is molded at the same time.
may be formed. In addition, inclining or curving the plane of the electrically nonconducting wall 10, or providing small-diameter holes will help improve the convection of hot water and eliminate dead water, so this should be done as necessary. .
On the other hand, the anti-corrosion power source 9 may be one that performs DC rectification of an AC power source or may be a DC power source itself, and is of a variable type with a variable applied current capacity. A pole of the anti-corrosion power source 9 is connected to either one of the heat collecting portion 1-a of the heat pipe 1 or the heat collecting fin 2. 11 is a hot water storage tank 3, a heat collecting part 1-a of a heat pipe 1,
It also shows an outer case in which the heat collecting fins 2 and the like are packaged.

The operation of the solar water heater configured as above will be described below. First, water is supplied into the hot water storage tank 3 from the water supply port 6, and the amount of water filled is automatically regulated by the buoyancy of the ball tap 5. Then, the heat collecting part 1 of the heat pipe 1 receives sunlight.
-a, the heat collection fins 2 are warmed, and therefore the medium in the heat pipe 1 evaporates and rises to the heat radiation part 1-b, exchanges heat with the water in the hot water storage tank 3, and descends.
The expansion of the hot water storage tank 3 due to heating overflows from the overflow port 7. Hot water is supplied from the hot water intake port 4. In this case, the tap water and groundwater supplied in each region may contain components that corrode metals.
The heat radiation part 1-b of the heat pipe 1 is oxidized and becomes blue water. If the hot water storage tank 3, ball tap 5, etc. are made of resin, corrosion can be avoided. Therefore, in order to mainly protect the heat radiation part 1-b of the heat pipe 1,
The electrically non-conducting wall 10 is arranged between the cathodic protection electrode 8 and the distance from the cathode protection electrode 8 to the heat dissipation section 1-b of each heat pipe 1 is made equal, that is, the water resistance therebetween is made equal. In this case, the anticorrosion current i flows almost uniformly, preventing the generation of blue water. In this case, since the heat collecting fins 2 made of Al or the like are fitted across the heat collecting portions 1-a of the heat pipes 1 in the vertical rows,
Connect the poles of the anti-corrosion power supply 9 to the heat collecting part 1- of the heat pipe 1.
If they are connected to either one of a or the heat collecting fins 2, they are all electrically connected to the same potential.

Without this electrically nonconducting wall 10, the heat dissipation part 1-b of the heat pipe 1 directly under the cathodic protection electrode 8 has the minimum distance and small water resistance, and therefore the anticorrosion current i is concentrated and becomes maximum, resulting in excessive corrosion protection. . On the contrary, the distance to the heat dissipation part 1-b of the left and right heat pipes 1 which is farthest from the cathodic protection electrode 8 is the maximum, the water resistance is also large, and therefore the corrosion protection current i is insufficient. Blue water cannot be avoided. In addition, the position of the cathodic protection electrode 8 must be determined at an optimal low position with residual hot water in anticipation of a decrease in the amount of hot water in the hot water storage tank 3 due to the user's hot water supply operation. It will continue to double.

As described above, according to this embodiment, by arranging the electrically nonconductive wall 10 between them, the heat dissipating portions of each heat pipe can be almost uniformly protected against corrosion.

Effects of the Invention As described above, the present invention produces the following effects by providing an electrode for cathodic protection, and is of great value.

(1) Basically, 1 solar water heater has 1
It is sufficient to provide just one cathodic protection electrode, and there is no need for a large number of the same electrodes, making it possible to provide an inexpensive product with excellent corrosion protection performance.

(2) When installing solar water heaters in parallel and connecting them with piping according to the amount of hot water required by the user, set the current application capacity of one anticorrosion power supply in advance so that it can be doubled according to the number of the same water heaters. The same effect can be obtained by connecting the poles of adjacent water heaters to each other.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a solar water heater according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along line A-A' in FIG. 1... Heat pipe, 1-b... Heat dissipation section, 3...
... Hot water storage tank, 8 ... Cathodic protection electrode, 10 ...
Electrically non-conducting wall.

Claims (1)

[Claims] 1. A hot water storage tank in which a heat radiating part of a heat pipe is disposed, a cathodic protection electrode fixed to a lower part of the hot water storage tank, and an electrically nonconducting material between the heat pipe heat radiating part and the cathodic protection electrode. A solar water heater installed on a wall.