PURPOSE: To prevent the corrosion of the heat collecting plate by forming a coating layer consisting of an excellent heat-resistant, acid-resistant and waterproof coating substance to inner and outer surfaces in the heat collecting plate for solar heat for absorbing solar rays.
CONSTITUTION: The first coating layers 4 consisting of the excellent heat-resistant, acid-resistant and waterproof coating substance are formed to the outer surface and inner surface, in which a thermal medium is circulated, of a heat collecting plate blank 1 composed of a metal. Accordingly, the corrosion of the blank 1 can be inhibited by the first coating layer 4 of the inner surface even when using water of low quality, and the leakage of water can be prevented by a sealing effect of the first coating layer 4 of the outer surface of the blank 1 even when the blank 1 corrodes for one cause or another and a hole is penetrated. Paints containing metallic powder of excellent infrared reflection are applied onto the first coating layer 4 of the outer surface to form the second coating layer 5, paints containing a black pigment absorbing solar rays are applied onto the coating layer 5 to form a third coating layer 6, and selective absorbency is provided thereto.
MAKI MASAO
KANEKO YASUNORI
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