Description：Before the masonry construction, firstly, clarify the construction tasks; secondly, do the “three checks”, that is, check personnel, check materials, and check the site; then, be prepared to eliminate hidden dangers and reduce problems; finally, make a plan to deal with it. Possible accidents.
Title：struction and masonry method of refractory bricks in cement kiln
Keyword：refractory bricks, cement kiln, refractory motor
This Article Related Product : Magnesia carbon brick
- Masonry preparation
1. Analyze the drawings carefully, clarify the construction tasks, understand the design intent, and clarify the design requirements and key points of each part.
2. Visit the leaders of the designer, supplier, construction party, and application party to clarify the working and organizational relationships between the parties and the parties, implement their respective responsibilities, and clarify what problems they encounter and who should be approached to solve them.
3. Check the refractory materials, construction machinery and auxiliary facilities and tools that enter the site to confirm whether their varieties, specifications, quantities and quality meet the construction requirements, and whether the personnel and organizations involved in the construction meet the predetermined requirements.
4. Check the construction site carefully to observe whether the kiln is cleaned, whether the cylinder is deformed, whether the welds and connections are flat, and whether the block ring is perpendicular to the kiln axis. It is required to have sufficient lighting, smooth transportation, complete tools, intact mechanical and electrical equipment, and complete personnel. In case of mechanical and electrical equipment failure, it can be eliminated in time.
5. According to the construction tasks and actual conditions of the site, prepare the progress plan and cross-work plan of the masonry project, prepare the construction technology, material and work, and formulate the plan in case of failure to ensure that the kiln lining construction is carried out in a harmonious and orderly manner and reaches the maximum excellent quality.
6. Before laying bricks, after cleaning the site, put the line. The longitudinal reference line of the kiln is placed every 1.5m along the circumference, and each line is parallel to the axis of the kiln. The hoop reference line is placed every 10m, and each line is perpendicular to the axis of the kiln. In addition, it is necessary to draw construction control lines parallel to the circular or longitudinal reference line, and place one construction control line every 1m.
- Basic requirements
The basic requirements of bricklaying: brick lining should be close to the kiln body, that is, the” four corners” of the cold end of the bricks( the big end of the brick and the kiln body should be fully attached to the kiln body without leaving seams),the bricks should be tight, the brick seams should be straight, and the bricks should be circled. To ensure that the brick ring and the cylinder are reliably concentric, the kiln lining structure is stable, so that the pressure of the cylinder on the brick ring and the internal stress of the brick lining are evenly distributed on each brick in the entire lining to prevent stress concentration. The layout of refractory materials in the kiln barrel is shown in Figure 1.
It can be seen from Figure 1 that the four corners of the large head of the refractory brick must be closely attached to the inner surface of the cylinder; the axial seam of the brick must be strictly parallel to the central axis of the kiln body; the radial seam of the brick must be strictly perpendicular to the center of the kiln body axis. According to the reference line released in advance, the orientation of the brick lining can be determined. If the reference line cannot be seen clearly, the orientation can be determined according to the horizontal and vertical welds on the cylinder. Once the kiln lining is found to be deviated, it must be corrected in time with fire mud and joint-filled steel plates. When correcting, pay attention to the width of the fire mud joints＜3mm. The thickness of the joint-filling steel plate is 1-1.2mm, and it is required to be flat, not crimped, not twisted, and free of burrs. Each piece is smaller than the width of the brick or the height of the brick by 10mm, and the width is 20-40mm. When the deflection is large, it takes several bricks to correct it.
Pay special attention to the masonry: it is absolutely not allowed to build large or small heads of refractory bricks. Even if only the size of a brick is reversed, the kiln lining must be resolutely removed and re-construction. Otherwise, major equipment and personal accidents may occur.
- Masonry method
Arch frame method is commonly used for laying bricks in large rotary kilns. Small and medium-sized rotary kilns can also be used for bricklaying by pole method.
The arch is a sliding pneumatic device installed on a movable platform, and the bricks are pressed against the kiln body through a hydraulic device. The masonry procedure is:
- Lat the brick lining of the lower half circle
- Install the mobile platform with a metal clamping device to make the hydraulic cylinder in place
- Place the brick on the clamping device and press it on the kiln body by hydraulic cylinder
- Before locking the bricks, use a jack to prop up the bricks on both sides to squeeze the brick lining tightly before locking the bricks
As can be seen from the picture, firstly, build the lower half circle of bricks; secondly, build the support frame with horizontal wood and top bars. Next, turn the kiln 90°, build the bricks at 1/2 to 3/4 of the circumference, and build the second road support frame, then turn the kiln 90°. Then, lay the remaining lining bricks until the brick opening is near; turn the kiln around 45° to lock the bricks.
Special emphasis: the following two issues should be paid attention to when laying bricks with the jacking method: one is that the height of the jack must exceed the semicircle of the kiln; the other is that the side of the cross wood contacting the refractory bricks should be nailed with elastic materials such as rubber, or the cross wood should be nailed tightly with a wooden wedge, every brick pressed.
If the top cylinder is not a semicircle, when the kiln rotates 180°, the lining bricks on the top of the top cylinder(before the brick kiln is located at the bottom of the top cylinder) will collapse due to loss of support. In the same way, if the horizontal wood is not nailed with rubber or wood chips, if the kiln body is deformed and some of the bricks are not pressed by the horizontal wood, the unpressed bricks after the rotary kiln may loosen or even collapse. Since the collapse of the kiln lining may cause serious casualties, it must be carefully checked to prevent accidents.
In addition, if wet masonry is used, it must be ensure that the mortar in the brick joints is full and the size of the brick joints should be controlled within 2mm.
- Lockstitch method
Locking bricks is the process of using the main bricks, inserting bricks, steel plates and fire mortar to complete the final masonry of a circle of bricks and closing the bricks circle.
Insert bricks are lining bricks whose main bricks are reduced by 10mm, 20mm, or 10mm thicker. Under normal circumstances, at least 2 types of inserts should be prepared for each circle, at least 2 pieces of each. The thickness of the seam filling steel plate required for the lock seam is 2mm, 1-1.2mm and the length and width are slightly smaller than the main brick. Also need to adjust the length and width of the steel plate. The steel plate is required to be flat, not crimped, not twisted, and free of burrs. When the bricks are locked, the masonry and fastening of the last brick are shown in the figure.
Pay attention to the following points when locking the bricks:
- Processing bricks cannot be used as lock-seam bricks
- When several lock bricks need to be used, the lock bricks should be used separately
- The axial seam of the lock seam brick should be parallel to the kiln axis
- The thickness of the lock seam steel plate is less than or equal to 2mm, and it should be used dispersedly
- Several steel plates cannot be driven into a brick joint, so as to avoid the oxidation and expansion of the steel plate and damage the refractory materials
- After the bricks are locked, try to drive steel plates into the cracks in the bricks where there is a possibility of looseness until no one can be hit
- Can not directly process refractory bricks with metal tools
It is especially emphasized that under any circumstances, it is absolutely not allowed to directly hit the refractory bricks with a hammer! Otherwise, the injured firebricks may suddenly be damaged, which may cause serious personal and equipment accidents.