The use of rotor impact pulverizers for the comminution of slightly to moderately abrasive materials

摘要

The first rotor impact pulverizer was manufactured in 1980. The demands imposed on concrete sands by the expanding dry mortar industry and the construction industry prompted the design of this new type of mill. The aim was to supersede the hammer mills that had often been used up to that time by a machine that was optimized both mechanically and process technologically and was easier to service. Figure 1 shows a rotor impact pulverizer of construction size RPM 1513. Figure 2 depicts the design of the machine. It consists of the following subassemblies: frame with motor bearing assembly, lower machine section with drive unit, upper machine section with cover and rotor. The machine tower, consisting of the upper and lower sections, is mounted via rubber vibration absorbers on the frame. These absorbers attenuate the minor vibrations that occur in any fast running machine and are thus not transmitted to the sub-structure. The electric motor of construction type V5 is mounted on a rocker in the frame. The V-belts are tensioned via this rocker by means of a tensioning screw. The circumferential speed of the rotor can be altered by either changing the motor V-belt pulley or by operating it with a frequency converter. The lower machine section consists of a stable welded construction and accommodates the bearing assembly of the vertical shaft. It is specially formed to allow ground material to form deposits that provide autogenous protection for the machine housing. In addition, the housing is protected by inserted wear plates.