To uniformly cool as to even long-length work in the vertical direction at high velocity.
A vacuum heat-treatment furnace 10 is provided with a vacuum vessel 6, a heat-insulating material 1, heat exchangers 2A, 2B, cooling fans 3A, 3B and cooling pipes 4A, 4B as gas distributing devices. In the vacuum vessel 6, the upper part gas flowing passage which goes from the upper side range in the heat-insulating material 1, passing through the heat exchanger 2A, the cooling fan 3A, the cooling pipe 4A and a nozzle 13A in this order, and returns back to the upper side range in the heat-insulating material 1, and the lower part gas flowing passage which goes from the lower side range in the heat-insulating material 1, passing through the heat exchanger 2B, the cooling fan 3B, the cooling pipe 4B and a nozzle 13B in this order and returns back to the lower side range in the heat-insulating material, are constituted.
JPH0726696U | 1995-05-19 |
Toshio Ozawa