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Construction and acceptance requirements for top-fired hot blast stoves
Jan 08, 2019

In the top-fired hot blast stove, the lattice bricks with certain pores are arranged in an orderly manner, and the upper and lower through holes of the lattice bricks can be allowed to pass through the gas. According to the technical requirements of different temperature zones, siliceous bricks, clay bricks, etc. are generally used. In some hot air stoves, high alumina bricks, mullite bricks, and sillimanite bricks are also selected.


 


The masonry of the lattice bricks has been clearly defined in the metallurgical standards, as follows:


1. Before laying bricks, you must check the furnace rafts and pillars. The installation quality of the furnace rafts and pillars not only affects the masonry quality of the lattice bricks, but also relates to safe production. The deviation of the surface smoothness of the upper surface of the furnace and the allowable deviation of the center line of the furnace grid and the design position are prerequisites for ensuring the quality of the lattice brick masonry. When checking by the wire drawing method, the flatness deviation of the upper surface of the furnace rafter shall be 0~5mm, and the allowable deviation of the center line of the furnace rafter hole and the design position shall be 0~3mm.


2. The dimensional deviation of the checkered brick shall be checked and accepted according to the relevant provisions of the current industry standards. Before use, the usage plan should be determined according to the spot check record of the size of the checker brick. For the upper and lower porous lattice bricks with grooved tongues, the matching layer should be selected according to the height classification to ensure the flatness of the brick layer after the lattice bricks are built.


3. In order to achieve high air temperature or reduce gas consumption, high-temperature infrared radiation environment-friendly coating should be applied on the surface of the regenerator and the vault before the upper lattice brick is built, refer to GB/T30163. The coating uniformity should be checked after coating and there should be no leakage spots larger than 200 mm2.


4. The grid hole at the center point of the regenerator should be used as the reference for determining the control line of the horizontal cross center line of each layer of grid bricks. Each layer of grid bricks should be built from the horizontal cross center line to the surrounding area, and the grid hole should be kept vertical. . In the construction of checker bricks, the bricks can be controlled at the same time with wooden scales. The center control line should be made inside the surrounding furnace wall during construction. The misalignment between the upper and lower two-layer lattice bricks should not exceed 5 mm.


5. In order to ensure the masonry quality of the whole lattice brick, the first layer of lattice bricks should be pre-built to understand whether the actual size of the lattice brick matches the casting size of the furnace grid hole. The surface of the first layer of checkered bricks should be flat, laying a good foundation for the masonry of the upper layer of checkered bricks. The displacement of the brick hole to the hole of the furnace should not exceed 10mm, and the number of complete holes should be counted and the hidden engineering record should be filled. The furnace wall masonry and the lattice brick masonry alternately, and the lattice bricks must be lower than the wall bricks 1~2 layers during the masonry process.


6. In order to prevent the lattice brick from being heated and then squeezed to the furnace wall, it is ensured that the lattice brick and the furnace wall respectively expand and do not affect each other in the production process, and the expansion joint should be left between the surrounding lattice brick and the furnace wall according to the design regulations. In order to prevent the grid brick from being displaced around in the cold state, it is ensured that the grid hole is vertical and vertical, and the expansion joint is fixed by a wooden wedge.


7. Anti-scaling measures should be taken during construction, and the grid holes should not be blocked. After the plaid bricks are finished, the final cleaning should be carried out and the cells should be inspected. If the light of the lamp can pass through the cell hole, or if the steel bar that is lowered from the top by the rope can pass the full height of the cell hole, the cell hole should be considered qualified. The number of blocked cells should not exceed 3% of the number of complete cells in the first layer.


8. When the lattice brick adopts the porous lattice brick with the upper and lower tongues, the upper and lower layers should be staggered and masonry, and the expansion joint should be reserved between the brick and the brick according to the design regulations. The surrounding grid bricks should be pre-machined, and the arrangement diagram should be drawn in order.


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