PURPOSE: To improve the construction of an auxiliary heat-exchanger to be used for preventing the stagnation of noncondensable gas in a heat-transfer tube.
CONSTITUTION: A heat-transfer tube passing through the evaporation part of a vacuum boiler-type evaporator is provided with a by-pass line branching at the upstream side of the evaporation part and joining at the downstream side. The by-pass line is passed through an auxiliary heat-exchanger placed in a condensed liquid return line extending from the evaporation part to the evaporator pot. The apparatus has the following merits. (1) It is not necessary to extend the pipe to the installation site of the auxiliary heat-exchanger in contrast with conventional apparatus to use an external fluid as a cooling medium and, accordingly, the apparatus cost and installation space can be reduced. (2) The supplying source of the external fluid and the operation cost of the source can be eliminated. (3) The thermal efficiency of the evaporator is improved by the effective utilization of the condensation heat of the steam for the evaporation of the low-temperature fluid.
HANAMURE MASAKAZU
MIURA TOSHIYASU
SATO YOJI
SHOTANI HITONOBU
IKEDA SEIDO
SUMITOMO PRECISION PROD CO