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Retention Specification For Expansion Joints Of Refractory Castables
Jan 02, 2019

The thermal expansion of the refractory castable is mainly related to the aggregate of the aggregate, which is roughly the same as the thermal expansion of the refractory brickwork of the same material.

The furnace body built with refractory bricks, because the refractory mud in a large number of brick joints can be compressed, the expansion of the masonry after heating, so the total elongation is small, the refractory castable prefabricated parts or the on-site pouring furnace In the inner lining, the total elongation of the furnace body after thermal expansion is large. If there is no proper expansion joint, the lining will be bent, squeezed or deformed at the steel structure at both ends of the furnace body.

1. Expansion value of refractory castable

The setting of the integral cast refractory lining expansion joint shall be stipulated by the design. When the design does not specify the value of the expansion joint, for clay or high-aluminum refractory castables, the average value of the lining expansion joint per meter length can be as follows:

1 clay refractory castable is 4~6mm;

2 high alumina cement refractory castable is 6~8mm;

3 phosphate refractory castables are 6~8mm;

4 water glass refractory castable is 4~6mm;

5 Portland cement refractory castable is 5~8mm.

2. Expansion joint filler

The filler and thickness of the refractory castable expansion joint shall be designed according to the design. When the design is not specified, it shall be filled with asbestos board or plywood, and its thickness is 4~5mm.

3. Form of refractory castable expansion joint

The form of the refractory castable expansion joint is basically divided into two types, a through seam and a non-through seam, such as

4. Expansion joint expansion

The retention of the refractory castable expansion joint is mainly to select the spacing, width and form of the expansion joint. The pre-formed furnace body and the cast-in-place furnace have different distances between the expansion joints.

1The furnace body assembled by prefabricated components, if assembled with prefabricated parts, if the furnace body is short, there is no need to leave additional expansion joints between the prefabricated parts, only need to leave appropriate gaps at both ends of the furnace body; if the furnace body is long, According to the temperature of each section of the furnace body, an expansion joint is left every 5~10m along the length of the furnace body. The joint is filled with asbestos rope impregnated with clay mud to prevent the smoke from escaping at low and medium temperatures. Get angry.

2 On-site casting of the furnace body. The cast-in-place refractory castable furnace body is provided with the spacing and width of the expansion joints. Can be referred to Table 1. The values in the table apply to clay and high alumina refractory castables.

3 fixing of the filler. The material of the expansion joint in the refractory castable should be fixed in place before pouring or carefully filled in the casting. When the block is poured, the refractory castable should be divided into several pieces according to the expansion joint and separated from the expansion joint by the template. Casting, embedded in the joint filler after initial setting.

4 to prevent displacement. In order to prevent the displacement of the expansion joint filler or the local refractory castable adhesion, the filler layer should be cut accurately and tightly laid. If necessary, nails can be used to nail the castable to stabilize the filler layer.

5 isolation measures. When the packing layer is in the cold state in the construction environment and is in contact in the hot state, that is, when it becomes a slip surface, it is preferable to increase the separation layer to prevent the displacement of the packing, prevent the slurry from sticking or block the expansion gap.

5. Notes

Pipes and components that pass through the refractory castable shall be wrapped with asbestos rope and asbestos board.

For dense small tube bundles, you can pack 350 linoleum paper or brush asphalt (brushing thickness is 2mm).

6. Allowable error of expansion joint

(1) The allowable error of the vertical expansion of the vertical expansion joint is not more than 2mm per meter height, and the full height is not more than 15mm.

(2) The allowable error of the horizontal expansion joint is not more than 2.5mm per meter and the total length is not more than 15mm.

(3) The error of the expansion joint of the power station boiler is allowed to be 3~4mm.

(4) The allowable error of the width of the expansion joint is shown in Table 2.

(5) All kinds of refractory castables cast on site shall be provided with expansion joints according to the design drawings. The width error shall be +3mm and shall not be less than the specified width.

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