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Notes for construction of castable for flue lining

April 21, 2022

The construction of castable for flue lining can be carried out after installation, or the lining can be constructed before installation. The temperature of the flue is not high, but the smoke and dust and acid erosion are very large, especially the heat exchanger should be washed with water, which brings great impact on the construction and use of the lining material.

For the construction of the lining castable of the flue, 3mm gap should be left between each castable to set expansion joints. Castable construction is a piece of castable adjacent to the sealing material before the next piece of casting.


If it is installed after the completion of lining construction, relatively better. It is easy to construct the large diameter flue liner with castable. However, if the large diameter pipe is heavy, the lining construction will be carried out before installation, which will double the weight of the pipe, increase the installation risk and make it difficult to weld components. Therefore, the large diameter flue liner is suitable for construction after installation.


The construction of refractory castable for flue lining before installation is suitable for the construction of castable for small diameter flue lining because of its light weight. Construction before installation also reduces the difficulty of aerial work, castable is carried out on the ground, low labor intensity and high construction efficiency. The disadvantage is that the lining construction can not be carried out continuously, and the expansion joint is not easy to deal with.


The construction of castable for flue lining should pay attention to safety first, then the welding of anchor parts and the way of castable casting. For large-caliber flue, the anchor nails are welded first, then the anchor parts are painted, and then the construction is divided. The construction is divided into three and four valves after the construction of two valves within 180°, the pipeline is turned to 180°, and then the construction of three and four valves, if there is a insulation layer, the insulation layer of the insulation castable, and then the construction of wear-resistant castable working layer.


In addition, if the pipeline lining has two or two kinds of castable construction, it is also necessary to separate the construction of 4 pieces, but the construction of each piece can be stopped for 12 hours before the construction of the next piece, the first casting construction of the lower half, and then the flue is turned over on the ground, casting the other half.


If it is lined on the ground, the pipe opening should be corrected and deformation prevention measures should be taken. Prevent pipe opening deformation due to large or light weight in construction. During castable construction, the position that is easy to deform should not be constructed first, and the lining construction should be carried out on the dismantled position after the construction of other parts is completed.


For pipe elbow, expansion joint and valve, castable shall be constructed in sections, and expansion joints shall be reserved for pipe sections in horizontal and vertical directions. The position of the position is not high can be taken to support the inclined mold casting, and vibrating compaction, cut off the excess part along the tangent line. If the space is small and the construction joint position is high, the castable construction adopts flat port butt, and 3mm high temperature resistant ceramic fiber felt is clamped into the joint, and then group welding is carried out.