APPARATUS FOR DRYING COATED ARTICLES BY INFRA-RED RADIATION

摘要

PCT No. PCT/EP85/00066 Sec. 371 Date Oct. 24, 1985 Sec. 102(e) Date Oct. 24, 1985 PCT Filed Feb. 22, 1985 PCT Pub. No. WO85/03766 PCT Pub. Date Aug. 29, 1985.The present invention relates to a process for drying coated workpieces, particularly workpieces of irregular shape, by infrared radiation and to an apparatus for carrying out this process. The present invention can be used for drying castings, particularly those having an irregular shape, thin-walled sheet-metal products as well as ceramic and glass products which have been coated with a powder or an electro-dipping varnish or water-soluble or solvent-containing varnishes. According to said process the workpieces are dried by infrared radiation in several zones at a specific temperature, an air flow being provided in the zones and the air being drawn off from one zone. According to the present invention the workpieces are preheated in the first preheating zone. In the second rest zone the infrared radiation is interrupted so that the temperature of the workpieces slightly decreases. In the third reheating zone the workpieces are completely dried by subjecting them once more to infrared radiation while the air is circulated and heat is additionally supplied to the workpieces by convection. The apparatus comprises a casing, wherein infrared emitters having reflectors are disposed in several zones at intervals from the casing walls, the emitters encompassing an irradiation space. The apparatus also has inlet and outlet openings and a means for conveying the workpieces through the casing and a suction device. According to the present invention a rest zone without any infrared emitters is disposed between a preheating zone and a reheating zone. The suction device in the rest zone is so disposed that the air is circulated within the casing.