Rotary kiln shell as rotary kiln’s pillar and rotation part holds on at a high-temperature state under running. Because the rotary kiln shell has joints, which will be burned to deformation. When it gets serious, it will severely damage the normal running of rotary kiln, if the new shell joints do not be switched in time.
The Common Reason Of Kiln Shell Deformation
- Overlarge yield. Add more abrasion on shell material in the kideye to cause kiln shell’s overheat deformation.
- Overload heating flow. The length of the cooling zone is too short or rotary kiln even doesn’t have a cooling zone. Kilneye’s working circumstance is bad where the outlet clinker’s temperature is between 1300℃ to 1400℃ and the secondary winding is between 1000℃ to 2000℃.
- High thermal expansion. High-temperature resistance materials’ strength declines sharply.
- Bolt looseness on kilneye backplate causes fire tolerance materials falling off to burn down the kiln shell.
- Using polluted earth. When disposal improperly, it will cause badly corrosion to shell even burn down it.
- Sulphur, phosphorus and chlorine’s corrosion to the kin shell. They not only decline shell’s thickness and strength but also add steel materials’ brittleness. It may damages the kiln shell.
Methods To Prevent Kiln Shell Deformation
- Add shell’s rigidity. Use welding to replace rivet because rivet shell will cause the surface too smooth to lay refractory bricks and the rivet will loose when heating. So modern rotary kiln all adopts welding shell with the advantages of simple structure, lower cost, lightweight and good strength; Increase the thickness of the steel plate. Productive practise and theoretical analysis shows that general rotary kiln under axial bending strength has a big degree of safety but less rigidity, so it will have large radial deformation; Adopt reinforcing ring. It was a widely used way to set several reinforcing rings on kiln shell to enforce the rigidity of shell.
- Adopt proper gap value of backplate between the tyre and rotary kiln cylinder. When designing a rotary kiln, the gap value should be as small as possible. Under ideal condition, when the rotary kiln is running, the tyre should waling the cylinder backplate fitly, which creates no interference and no gap. The cylinder’s deformation under tyre is in accordance with the tyre, which not only has the function of strengthening radial direction rigidity, but also avoids the massive necking temperature stress. You can take the measures below: make sure your backplate is replaceable to switch regularly and hola on fitful gap; Adopt wear resistance materials as your backplate to longer the working life of the backplate; Lubricate the surface of the tyre to decline the wear out between tyre and cylinder. Adopt the grease including graphite or MOS, owning to the cylinder’s surface temperature can be 200℃ to 300℃.
- Strength the tyre’s rigidity. When the gap value between tyre and backplate is zero, the radial deformation of cylinder can be seen as the same to tyre deformation. The cylinder’s radial deformation depends on the rigidity of tyre.