Abstract: A screen module for a size reduction machine has a rigid screen having a tapered apertured wall formed in a frusto-conical shape. The rigid screen has an open wide end and a flat end. The wide end is mountable within a channel of the size reduction machine at a predetermined distance from a complementarily shaped impeller. The module has a fine screen nested within the rigid screen and against the tapered apertured wall. The fine screen has a wide end and a narrow end corresponding to the apertured wall. An adaptor disc is releasably secured within the rigid screen at the flat end. The adaptor has a tapered outer perimeter for seating against the tapered apertured wall when the adaptor disc is secured within the rigid screen, clamping the narrow end of the fine screen therebetween. A clamp ring is releasably secured at the open wide end of the rigid screen.

Abstract: A size reduction machine for use in process industries to continuously and precisely reduce the size of particles, while controlling fines, comprises an impeller mounted on a rotatable shaft, a drive operably connected to the shaft for effecting rotation of the shaft. The shaft and impeller are vertically mounted within a vertically extending channel having an input and an output. A screen has a tapered apertured wall formed in a frusto-conical shape. The screen is rigidly mounted within the channel so that any particles passing from the input to the output pass through the screen. The impeller is shaped and mounted so that a gap between an edge of the impeller and an interior of the screen remains substantially constant as the impeller rotates relative to the screen. The improvement comprises the drive being operably connected to the shaft at a point under where the impeller is mounted onto the shaft.

Abstract: An extensible spacer device for setting a gap between an impeller and a screen of a size reduction machine comprises a first collar having an axially extending bore, an internal thread on an inside surface of the bore and a circumferential shroud extending axially, a second collar having a base portion, a barrel portion and an axially bore extending therethrough. The barrel portion has an external thread adapted to threadingly engage the internal thread. The shroud is adapted to cover the barrel portion and frictionally engage the base portion when the first collar threadingly engages the second collar. A calibrated scale is on the base portion and a plurality of gradations circumferentially extends about the shroud to indicate an axial length of the spacer device as the first collar is rotated relative to the second collar.