Great wall machinery has been focusing on manufacturing kiln grinding equipment for more than 57 years, and the grinding mills has been widely regarded as the top level in quality. Moreover, with Great wall machinery helps, 200,000-1,000,000 tons per year production lines had been established domestically and overseas, and won the great reputation from clients.

　　Currently, the vertical mill series products mainly include: slag vertical mill, cement vertical mill, raw material vertical mill, coal vertical mill and so on. For the need of market and client’s requirements, all the series of vertical mills has been upgraded. So let me introduce the differences in designing between coal vertical mill and slag vertical mill after upgrading.

　　1.Similarities.

　　The two working principles are basically the same. The raw materials are fallen to millstone through blanking device, then gradually moved to the edge by centrifugal force, and the materials are milled by a number of grinding rollers. The hot air coming through wind ring keeps blowing the milled materials and drying the suspended matters. The coarse size materials are blew back to millstone to re-grind, and the fine materials are brought into the separator by the hot air, the qualified fine powder is collected by the collector.

　　The structure of the coal mill and the slag vertical mill is roughly the same, mainly including rollers, millstone, rocker arms, separator, drive devices, frame, roller-pressing device, lubricating device, upper shell, caging device and so on.

　　2.Differences.

　　Now here are the differences between coal and slag vertical mill.

　　1)1、Disc-shape millstone and tire-shape roller sleeves in structure.

　　2)The rollers still can work by turn-over when abrasion, which can increase the capacity of coal mill, reduce abrasion and expend working time.

　　3)The crossing structures on the frame are not need. It is the support device on the wind box connecting the frame sections, and only one air inlet is need on the air box.

　　4) A pair of spherical roller bearings are used on the rollers, and the bearing seal cavity expends to the outside of frame which sealing up with dust gas. So, the air sealing machine is not necessary by the simple sealing design.

　　5)No need for auxiliary transmission device on vertical mill.

　　6)An explosion-proof valve is arranged on the upper shell for security, in case of coal dust explosion.

　　7)Do not need to install the discharge valve. The discharging port has a cover plate as little slag discharging from coal mill.

　　8)For the roller-pressing device, No.I loading cylinder are divided in design from frame, but directly fixed on the mill base by anchor bolt.

　　All in all, the both mills are widely accepted in the industry. The coal vertical mill mainly used in milling system of power, metallurgy, building materials, chemical industry etc., especially for coal pulverizing system of burning bituminous.