PREHEATING ZONE IN DIRECT FIRING TYPE STRIP CONTINUOUS HEAT TREATMENT FURNACE

摘要

PURPOSE:To improve preheating efficiency by arranging an eject at front part of a nozzle spouting exhaust gas in preheating zone, sucking high temp. exhaust gas in heating zone to enable injection thereof to the material to be treated in the heat treatment furnace communicating the heating zone and the preheating zone. CONSTITUTION:In the direct firing type strip continuous heat treatment furnace 1 communicating the preheating zone at front of the heating zone, the exhaust gas Tg1 in the preheating zone is sucked from a suction gas hole 2 and circulated with a fan 3. This exhaust gas Tg1 is spouted from the nozzles 6, 7 arranged at upper and lower parts of the material A to be treated. By this method, the high temp. exhaust gas Tg2 in the heating zone is sucked with the eject 8 arranged at the front part of the nozzles 6, 7. Then, the mixed gas Tg3 mixing with the above exhaust gas Tg1 is injected to the material A to be treated. In such a way, the exhaust gas quantity is increased and the coefficient of convective heat transfer is improved and also solid radiation heat transfer is increased and the preheating efficiency is improved.