Liner is used to protect the cylinder, so that cylinder from the direct impact of grinding and friction: the same time, different forms can also be used to adjust the grind of liner motion state of the body to enhance the grinding of the crushing effect of the material, there is help to improve mill grinding efficiency, increase productivity and lower metal consumption.
Ball mill liners are mostly made of metal materials, but also a small amount of non-metallic materials. In addition to protect the cylinder liner cylinder, but also the movement of the grinding law of impact, in order to adapt to different working state (crushed or broken bits) requirements, lining the shape and material are also different. When the order to crush the main, require the lining of the grinding capacity of a strong elected body, while lining should have a good fighting performance. High manganese steel ZGMn13 have sufficient impact toughness, and dealt a blow when it is able to work hardening the surface becomes hard wear-resistant. Therefore, the main crushing mill cylinder liner are mostly high-manganese steel manufacturing.
Where the finely ground-based, the lining of the highlights on the relatively small body elected to the ground on the weak, the impact is smaller than strong abrasive. Require lining has a good wear resistance. Domestic mill mainly used for fine grinding cylinder liner materials are generally wear-resistant white iron, chilled cast iron, ductile iron and other rare-earth manganese. In recent years, widely used in rubber liner. Shape rubber lining rubber layering generally peaceful lining of two parts.
According to the working state of the different mill, rubber lining of the bead is also made to be corresponding to different shapes in order to change the tube mill grinding body in the law of motion.
Rubber lining of the advantages and disadvantages:
a. Wear. As the rubber with good elasticity, the impact of the ball can withstand deformation, so that a smaller force, for soft materials, rubber lining service life 2-3 times higher than manganese steel liner, while the higher the material hardness, rubber lining of the the superiority of the more remarkable.
b. Corrosion-resistant. Steel liner plate acidic slurry can be corrupted, but the rubber liner on the acidic or alkaline medium, water, steam at a certain temperature is not sensitive, and only the oil and ozone (by the Grand Duke generated by the rate of point machines) it corrosion.
c. Easy disassembly. As the rubber liner, light weight, with the specification of quality rubber lining is only one-third to one fourth of manganese steel. Replacement of steel liner plates, often are required to unload all the balls out, but when you replace the rubber liner is not necessary.
d. Easy maintenance. The use of steel liner plates, often need to screw inspection, while the rubber liner leakage phenomenon rarely screws.
e. Rubber lining thin, the effective cylinder volume increases. The thickness of the lining is usually only 50mm.
f. Rubber marker system to plug the phenomenon of lattice panels less than the steel grid plate.
g. Rubber liner less noise at work.
Rubber lining drawback is: no heat, not suitable for use in the dry mill.
The type of lining
Mill liner wear and tear of the most common phenomenon is the formation of trough-shaped groove. To avoid this situation, the surface shape of mill liners made various improvements to make the distribution of grinding media from a variety of slide down one of falling behind. For grinding to maintain the correct movement of the track is virtually impossible to install by changing the mill speed to solve this problem, and proper selection of mill liner surface grinding body shape is to solve the only way to track the movement. According to the shape of the work surface can be divided into flat lining, layering lining, convex edge lining, hemispheric lining, small ripple liner (5 bolt liner) and the cover liner.
a. Flat lining: Where the surface smooth or cast a pattern of the lining are all flat lining, its role in grinding media and liner are basically dependent on the static friction between the grinding media for grinding a certain enhancement of the role of . When wet coefficient of friction between them is 0.35, when the dry mill 0.4. The flat liner to enhance the friction coefficient of grinding required to be larger than the above data, have resulted when the rotary cylinder grinding the inevitable slide to appear, reducing the grinding speed and increase the rise in body height, is because there is sliding phenomenon, an increase of grinding role. Therefore, flat lining mainly applies to the fine grinding mill of the cylinder.
b. Layering liner: from flat lining and the pressure of the composition, layering on bolts, through the layering (bolts) will be fixed liner.
The layering of this liner than lining the high pressure side of the grinding of the thrust and the flat lining of the grinding friction of the body so that the higher grinding up with a larger impact energy. So batten lining apply to the crush (rough grinding) as the main mill cylinder. Especially for large particle size materials, high hardness of the situation is even more suited to layering lining drawback is that the ball high degree of non-uniform, the pressure of pre-grinding with high side and away from the grinding pressure of the local body as in the flat lining as a partial fall, when the mill speed is high, the pressure of the former side of the grinding belt is too high, Paola liner to the opposite, not only the crushing impact was small, but accelerated the liner and grinding media wear and tear on the speed of the more high mill liner is not fit for. Layering lining the main parameters are the height and density layering. Should not exceed the height of bead mill (or the warehouse) the largest ball of radius. Layering of the slope angle should be preferably 400-500. 2 the distance between the bead is equal to the mill (warehouse) Maximum of 3 times the ball through for the best.
c. Convex edge lining: It is cast in the flat liner on the semi-circular convex edge. The role of convex edges and layering the same. It is rigid, difficult deformation, but the ridge after lining a worn lining block must be replaced, it is better layering lining the economy.
d. Wave, lining: Making ridge flat lining of the convex edge of the wave formed liner. This ball-handling ability liner liner worse than the ridge, in a wave section, the increase in part in raising the grinding is very effective, while the decline, some of them some of the adverse effect. This liner used in rod mill or rod mill of the rod position.
e. Step lining: lining surface of an angle, so that the friction angle with the original synthesis, after installation into a number of steps, you can increase the lining of the grinding body thrust. Ladder liner right at the same level enhancement of a high degree of ball uniform, lining the surface changes its shape after wear and tear was not significant, to prevent sliding between the grinding media and wear. Ladder liner for coarse grinding and multi-positions crushing mill warehouse.
f. Hemisphere-line lining: lining can be completely applied to the hemisphere line to avoid liner to generate ring groove wear and tear, can greatly reduce the grinding body and lining of metal consumption, smooth liner surface area can increase production by about 10%. Hemispheric body diameter should be for the mill (warehouse) the largest diameter ball two-thirds of the hemisphere center distance is not greater than the mill (warehouse) the average of two times the ball diameter, hemispheric to be arranged into a triangle-line to facilitate the block steel sliding the ball along the cylinder.
g. Ripple liner: This is suitable for fine grinding mill (warehouse) to install the non-liner bolts. To the peaks and pitch are small.
h. Hierarchical classification lining the main characteristics of liner along the axis with a pitch. Installed in the mill grinding direction is towards the end of big-endian, that is close to the expected end of large diameter, discharging end of a small diameter. The shape of this liner will cause grinding mill according to their size along the channel within the automatic classification, resulting in large-diameter of the grinding mill to remain in the feed-side area, small diameter grinding media gathered near the mill discharge material side of the side. A self-steel ball grinding machine will be descending axial direction of the arrangement, that can automatically grade, in line with the requirements of material grinding process. And hence reduce the number of mill positions to increase the effective volume of mill to reduce the ventilation resistance, improve grinding efficiency and productivity, reduce consumption. In order to avoid the feed-side ball or a large accumulation of excessive coarse material can be loaded by the feed-side row of 1-2 flat liner. In order to avoid a small ball or materials focused on the mill’s discharge end, and it can depend on the exit liner installed as a 1-2 row of flat liner. Classification is only used for lining the ball mill and the mill warehouse.
i. Cover lining: Cover the surface is flat lining, with the bolt on the end cap fixed to the mill in order to protect the cover from wear and tear of grinding bodies and materials.
Specification liner
Liner size should take into account the size of the carriage, handling and grinding out the door convenience. In recent years, mill liner size has been unified, a width of 314mm, monolithic lining long 500mm, half a lining length 250mm, thickness 40-50mm, the quality of about 45-55kg.
Lining the fixed link and inserts a bolt puzzle in two ways. When the bolt liner, the liner to make the body close to the tube wall, without the existence of loopholes. In order to prevent slurry or the materials were washed into the cylinder, should be installed between the liner and cylinder liner. In order to prevent the outflow of slurry along the bolt hole, fixed liner bolt with a washer with a conical surface. In the cone-plane filled race hemp ring, tighten the nut when the ring is tightly pressed hemp cone washer, so that bolt and cylinder bolt hole to eliminate the gap between Ji Bei. In order to relax, ask to take pairs of bolts nuts or anti-washer. Has the advantage of a fixed link bolt shock resistance, vibration, more reliable. The disadvantage is the need to drill in the cylinder, consuming human and material resources, reduced cylinder strength, and may leak material.
Ripple liner are generally interwoven framed puzzle in the cylinder body, tightening with each other when they form a “arch” structure, plus the condensation cement mortar curing, the general is very solid. To be able to tighten in the lining iron wedge tight ring from the users. Another non-bolt liner, and his side are on both sides with a semi-circle marketing lining each hole when tightened, the wedge-shaped pin into the pin hole. In the cylinder liner between the cushioned. Cast stone liner is installed, be staggered ring puzzle, not bolt. Normally fitted in a 10mm or so thick layer of adhesive materials.