GB819504A - An improved method and apparatus for grinding, comminuting, and dispersing materials - Google Patents

Abstract

819,504. Comminuting machines. SOC. D'EQUIPEMENTS INDUSTRIELS ET LAITIERS. Nov. 20, 1956 [Nov. 30, 1955], No. 35426/56. Class 59 [Also in Group III] The stator 2 and rotor 8 of a machine for comminuting materials each comprise a first portion conforming to a cylinder or a frustum of a cone of small vortex angle and provided with teeth 36, 38 with intervening slots, a second portion conforming to a plane surface or to a frustum of a cone of larger vortex angle and provided with teeth 40, 42 with intervening slots, and a third portion conforming to the frustum of a cone of smaller vortex angle than the second portion, the portions on the stator and rotor moving past each other on relative rotation between them with a small clearance between their facing surfaces. The first portions of the stator and rotor have equal numbers of slots 37, 39, the second portions have equal numbers of slots, and the teeth in both these portions have a greater peripheral dimension than have the slots. One of the third portions on either the stator or rotor is without slots, and the other has a plurality of slots which are between teeth 44 equal in number to, and a continuation of, the teeth in the second portion of the member and emerge directly into an annular discharge channel 52. The teeth 40, 42 are formed by radial slots in an annular flat or conical surface on the rotor and stator, the former being secured to a shaft 14 which is rotated in bearings 16 by a motor; if desired, the stator also may be rotated. The outer radial ends of the teeth 40 terminate at a substantially conical surface 48 which is approximately parallel to the teeth 44 on the stator in register with the teeth 43 (not shown). The teeth 36, on the cylindrical or conical surface co-operate with the teeth 38 on the stator so as to constitute a preliminary comminuting stage; the teeth 36, 38 which may lie in planes inclined to the axis of the machine, are less in number than the teeth 40, 42. The clearances between the teeth at the different portions are small compared to the depth of the channels and may be slightly tapered. The material, such as paper stock, is supplied in a liquid suspension and may be pumped through a conduit 10 to arms 34 located on the rotor to impart an initial comminution action and centrifugal force to the material which then passes along the channels 37, 39 between the teeth 36, 38 to an annular space 46. When two or more comminuting stages are employed, the spaces 46 may be replaced by conduits. The width of the teeth are wider than the channels 37, 39 so that during rotation the teeth of one of the members pass across the channels of the other member and thus are alternately coincident to form cylindrical channels and then staggered to form semi-cylindrical channels. From the annular space 46, the material is further comminuted between the teeth 40, 42 which are separated by rectangular slots to provide a similar action to the teeth 36, 38. The slots between the teeth 40 are alternately opened and closed at their radially outer end by the passage of the teeth 44 of the stator to impart an intermittent motion to the material which then passes along the slots between the teeth 44 to the annular discharge channel 52. It is stated that by closing the slots, accoustic waves are thereby generated. Impeller blades may be provided in the space 52 to aid the flow of material to one or more exit conduits. Specification 779,877 is referred to.