Normally, the surface of the rollers is not a cylinder and it will be a concave profile with both ends large and the middle small when the roller of the roll crusher worn out. At this time, large size clay pieces or mud group may go out through the notch without crushing, so the rollers need repairing.The methods of repairing the rollers generally include the following two:(1) Cutting (grinding) on the spotThe operating steps of this method is: install a dedicated knife rest whose moving track should be parallel with the axis of the roller at the frame of the roll crusher. Start the crusher when repairing and then cut the rollers with manual feed gear (automatic feed gear is ok as well if the condition permit). When using this method we should pay attention to the following few points:a) Keep the moving track of the knife rest parallel with the axis of the roller,in order to avoid appearing a taper after cutting , which will influence broken effect.b) Control the pace of the rollers. The line speed of the rollers surface should not be higher than allowable cutting speed of the cutter, or the cutter will be broken.c) As with the high hardness rollers, we should take the method of grinding the rollers by the use of wheelhead.(2) Welding on siteIt means welding filling of the worn notch. This method is simple and practical and do not affect the production, and the hardness and abrasion resistance of the overlaying parts are relatively good.Its only defect is that it is just suitable for the rollers of good solderability . When welding we should pay attention to the following points:a) Choose the right welding rod, a pile of 266 256 is advisable.b) Had better choose welding rod of a small diameter, it is standard to weld with the small current. Also it can reduce heat stress and avoid serious deformation and crack.c) In the process of welding, we should check the welding parts regularly with the ruler model to ensure a qualified size of the shape.d) Link the electric...