Topower Insulation Ceramic Fibre Blanket For Sale, Customer In United Arab Emirates Ordered 25tons
High quality thermal aluminum silicate ceramic fiber blanket widely used for industry furnace insulation refractory
The volume density of ceramic fiber refers to the ratio of the weight of ceramic fiber products to the total material. The size of the volume density is an indicator that determines whether the selection of furnace lining is reasonable. It is an important factor affecting the thermal conductivity:
The thermal conductivity of ceramic fiber products decreases with the increase of volume density, but the reduction gradually decreases, so that when the density exceeds a certain range, the thermal conductivity no longer decreases, but tends to increase. There is a minimum thermal conductivity and a corresponding minimum volume density at different temperatures, and the volume density corresponding to the minimum thermal conductivity increases with the increase of temperature.
Correctly understanding and applying the above rules is of great significance to the application of ceramic fiber blanket . The thermal insulation performance of ceramic fibers mainly utilizes the thermal insulation effect of the enclosed air in the pores of the products. When the specific gravity of solid fiber is constant, the greater the porosity, the smaller the volume density. When the slag ball content is constant, the influence of volume density on thermal conductivity actually refers to the influence of porosity, pore size and pore properties on thermal conductivity.
1 When the volume density is <96Kg/m3
Due to the enhanced oscillating convection and radiation heat transfer of the gas in the mixed structure, the thermal conductivity decreases with the volume density, and shows an exponential function relationship.
2 When the volume density is >96Kg/m3
As the volume density increases, the pores distributed in the fiber are closed, the proportion of micropores increases, the air flow in the pores is restricted, the heat transfer in the fiber is reduced (thermal resistance increases), and at the same time, the radiation heat transfer through the pore wall is also reduced accordingly, thereby reducing the thermal conductivity.
3 When the volume density increases to a certain range of 240~320Kg/m3
When the ceramic fiber blanket volume density increases to a certain range of 240~320Kg/m3, the contact points of the solid fiber increase, so that the fiber itself forms a bridge, and the heat transfer is increased through the bridge. Secondly, the increase in the contact points of the solid fiber weakens the damping effect of the pores on heat transfer, resulting in the thermal conductivity no longer decreasing and having an increasing trend. Therefore, porous fiber materials have an optimal volume density with the minimum thermal conductivity. The volume density of ceramic fiber on the hot surface of foreign layered ceramic fiber wall linings is stipulated to be 130~160Kg/m3. The volume density of ceramic fiber on the hot surface of flat-laid composite furnace linings is stipulated to be 200~240Kg/m3.
The volume density of fiber products on each layer after the hot surface of the furnace wall decreases gradually, because at high temperatures, the degree to which the thermal conductivity of ceramic fibers decreases with increasing volume density is more significant than at low temperatures. The fiber lining structure with each layer in the thickness direction matched according to density can maintain uniform thermal resistance in the thickness direction of the furnace lining. Under the same thermal resistance conditions, it can save fiber usage and reduce furnace construction costs.
