Shield furnace is used for the workpiece of the bright annealing and heat treatment equipment, is intermittent temperature furnace, furnace temperature is between 650-1100 degrees, according to the provisions of the heating system with time. According to the charging situation of the bell-type furnace, the furnace is divided into two types: square-type furnace and round-type furnace. The heat source of the bell-type furnace is mostly gas, followed by electricity and light oil, it consists of the cover, the inner cover and the furnace, the combustion device is set on the outer cover, the cover is set on the insulation layer, the workpiece is generally placed in the inner cover for heating and cooling.
 Bell-type furnace insulation advantages:  First, good air tightness, small heat loss; high thermal efficiency. Second, the furnace is without the door and lifting agencies and a variety of mechanical rotation mechanism, the cost. is low. Therefore, in the heat treatment of the workpiece,  the bell-type furnace is used widely.
Hood type bright annealing furnace insulation, control point of shell material selection:
Material selection: ceramic fiber module, the bulk density of 220Kg/m3, ceramic fiber blanket ;
Total insulation thickness: 330 or 350mm, ceramic fiber module 300mm, backing layer ceramic fiber blanket 30 or 50mm;
Heater burner parts: This area with a higher than the lining of the ceramic fiber module and ceramic fiber blanket.
The bell-type furnace lining adopts the laminar module composite structure, which firstly saves the steel consumption and reduces the overall cost of the lining. Secondly, the anchor is located between the ceramic fiber layer and the ceramic fiber module, which can guarantee the long service life of the anchor. The fiber orientation of the ceramic fiber blanket is perpendicular to the folding direction of the ceramic fiber module so that can effectively improve the sealing effect.