HEAT EXCHANGER

摘要

PROBLEM TO BE SOLVED: To remove surely even oils and fats mixed with drain hot water and deposited to a heat exchanging pipe. SOLUTION: A pipe-like evaporator 27 of a constituent of a heat pump is disposed in a drain hot water recovering tank 30 to store the drain hot water from a tableware washing machine 1. A bypass pipe is connected between the high pressure side of a compressor 24 and an inlet of the evaporator 27 where an opening/closing hot gas valve 62 is interposed. A temperature sensor 64 is set in the outlet side of the evaporator 27. In the completion of heat recovery, the running of the compressor 24 is continued while the hot gas valve 63 is opened and hot gas is supplied to the evaporator 27 so that the evaporator 27 is heated from the inside to liquefy an oil and fat film deposited on the surface. At the same time a shunt valve 54 is opened and the residue of warm water formed in the part of a condenser 25 is sprayed toward the evaporator 27 and flushed away. When the evaporator 27 is heated to a predetermined temperature, the supply of hot gas is stopped.