CONTROLLING METHOD OF HEAT EXCHANGING AMOUNT IN MULTI-STAGE SYSTEM SEPARATE TYPE HEAT EXCHANGER

摘要

PURPOSE:To permit to control the exchanging amount of heat and the outlet temperatures of exhaust gas as well as a liquid to be heated by a method wherein multiple stages of heat exchanging devices are provided and the level of operating liquid in an evaporating section is displaced in any one stage of the multiple stages while the heat exchange is operated or stopped independently in remaining stages. CONSTITUTION:The height l1 of the level of operating liquid in an evaporating section 1 is detected by providing a branch pipe 11 between both headers 1a, 1b of the evaporating section 1 with a level meter 12 or attaching the level meter 12' to a tank 3. The detecting signals 12a, 12'a of the level meters are sent into a liquid surface controller 13 to compare them with a present signal. On the other hand, a pipeline 5 is provided with an automatic opening and closing valve 10 in natural circulation system to control the opening degree of the automatic opening and closing valve 10 by the operating signal 10a of the liquid surface controller 13 and regulate the height l1 of the level of operating liquid in the evaporating section 1. Thus, the exchanging amount of heat is controlled finely in one stage from 100% exchange to the stop of it while the heat exchage is operated or stopped in other stages in accordance with the necessities. According to this method, the exchanging amount of heat of the whole of multi- stage type may be controlled finely.