For most thermal equipment, to save energy and improve working conditions, heat preservation is necessary. However, the insulation of some equipment is not necessary because of the advantages and disadvantages of insulation. Therefore, the actual situation and the performance of thermal insulation bricks should be considered when choosing suitable thermal insulation bricks.
The insulation bricks can be divided into the following types:
1) Refractory clay insulation brick GB/T 3994-2005
2) High alumina insulation brick
3) Mulite insulation brick
The principles of choosing insulation bricks include:
1) It should not affect the service life of the entire refractory masonry;
2) For continuous working high-temperature furnaces, generally large-area heat preservation is reasonable, which can reduce heat loss. However, for some special areas, such as open hearth roofs, insulation can reduce service life. For periodic working furnaces, regenerative heat loss is the main factor of heat loss. Insulation can increase the temperature of the masonry and increase the regenerative heat loss. Therefore, whether the regular working furnace should be insulated is determined after calculating the heat storage and heat loss.
3) Due to the high porosity of insulating bricks, they cannot bear excessive load and should not directly contact molten metal, slag and high-temperature dust.
4) Insulation bricks have low strength. Brick joints and expansion joints should be properly handled to avoid damage caused by volume expansion. Insulation refractory bricks should not be subjected to strong mechanical vibration, impact and friction;
5) Since the thermal insulation brick has a large linear shrinkage after reheating, the maximum working temperature should be less than 100℃ than the firing temperature.
