Equipment overview
Bell type furnace is composed of one heating cover, two furnace bases, two inner covers and valve frames.
The heating cover is a cylinder vessel that is welded by steel plate after bending into round shape . The heating cover has hoisting lugs for change, and three supporting legs below it. On its bottom, there are sand seal knives surrounding cover body, which are directly placed on inner cover flange, so as to improve seal effectiveness. There are two guide rings in the heating cover, therefore it makes the heating cover lifted and positioned on the furnace base easily and acurately.

Furnace lining is made of whole-fiber aluminum silicate needle felt blocks. So it can make the furnace weight light, improve the effect of heat preservation, and reduce the energy waste. The heating components are hung around the hearth symmetrically with resistance bands and fixed by ceramic bolts, so that they can be solid and can be used for a long time.

The furnace base takes circular shape and is welded by fireproof stainless steel plates. A round fireproof steel soleplate is placed on each furnace base, under which there are some support pipes to bear the weight of the workpieces. There is a strong convective fan in the middle of the furnace base. The fan impeller is driven by the motor to form the air convection in order to homogenize the temperature inside the furnace. The fan motor with two speeds is water cooled and sealed, capable of switch between high and low speed. So motor bearings use water cooling to avoid being destroyed by the high temperature. The rubber airproof ring with water-cooling on the furnace base is used to airproof the inner cover.

The inner cover is cylindrical and made of corrugated stainless steel. The top is circular head, and the bottom is welded with a flange to connect with the sealing ring of furnace base in order to make a hermetic space in the hearth. So the materials are heated and treated in a protective atmosphere.