To eliminate an inconvenience that a material to be treated is contaminated by reevaporating a binder from an inner exhaust system.
An inner box 2 is provided in a furnace 1 to form a treatment space 81 inside. The treatment space S1 is formed so as to directly exhaust gas outside the furnace 1 through an inner exhaust system 3. A valve mechanism 7, is provided at a position where one end 3a of the inner exhaust system 3 can communicate with the treatment space S1, which usually interrupts the communicating state of the inner exhaust system and the treatment space S1 and automatically ensures the communicating state only when the pressure of the treatment space S1 is higher than that of the inner exhaust system 3. Therefore, when a degreasing and sintering treatment is carried out, a binder reevaporating in the inner exhaust system 3 upon sintering can be prevented from flowing backward to the treatment space 81 and the clean atmosphere of the treatment space S1 can be maintained while maintaining the exhaust function peculiar to the inner exhaust system to exhaust the binder produced in the treatment space S1 upon degreasing outside the furnace 1 directly through the inner exhaust system 3.
TAKEDA MASAO
YAMAUCHI IPPEI
OTANI SHUICHI
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