Patent GB-1492161-A (GB)
Title: Pellet mill
IPC: A23L13/00
Filed: 1976-01-26
Abstract: 1492161 Pellet mill CALIFORNIA PELLET MILL CO 26 Jan 1976 [28 Jan 1975] 02928/76 A pelleting mill comprises an annular die 7, having radially directed circular passages 9 through which material is outwardly extruded, to be cut into the pellets, upon rotation of the die 7 around a pair of rollers 20 which are freely rotatable about stationary axes carried by a stationary frame, and material to be extruded is separately delivered to the nip of each roller 20 with the die 7, by a pair of feed tubes 31, 31<SP>1</SP>, carried by the stationary frame and each extending parallel to the axis of rotation of the die 7 and having a delivery opening 37 which is of a length equal to that of the rollers 20. For its rotation, the die 7 is clamped by a split locking collar 8, to a rotated tubular shaft 4 which surrounds a shaft 12 carrying the frame and which is secured, against rotation, to the machine frame 1 by shear pins (16), Fig. 1 (not shown), which shear to permit rotation of the frame, including the rollers 20 and tubes 31, with the annular die 7 upon engagement of an obstruction between the rollers 20 and die 7. The frame comprises a radial flange 17 secured to the shaft 12, and a plate 21 spaced therefrom and connected to the shaft 12 by a central bolt 22, the rollers 20 each being mounted for free rotation on a shaft having at each end an eccentric stud 23, Fig. 3, which locate in corresponding bores in the flange 17 and plate 21. Adjustment of each roller 20 with respect to the die 7, is effected by the studs 23 at their ends located in plate 21, each being secured to a part 24 having a pair of abutments 25 which are engaged by adjusting bolts 27 carried by the plate 21, whereby the studs 23 may be angularly displaced. The plate 21 also supports a pair of scrapers 30, and the feed tubes 31 are secured by a bolt 35 to the flange 17, and extend through the plate 21, against which they are located by a spring clip. Each feed tube opening 37 is directed towards the die 7, and is of a width which increases towards the flange 17 between an edge 38 extending axially, and an edge 39 extending helically between axial location 42 and 43 in the direction of flange 17. The position of each feed tube opening 37 is angularly adjustable by the bolt 35, the area of each opening 37 being at least substantially equal to the cross-sectional area of the tube. Each feed tube 31 or 31<SP>1</SP> is supplied with material from a separate hopper, e.g. 44, removably mounted in a housing 28 located adjacent the die 7 at a minimum clearance, to prevent loss of material, provided by tapering surfaces of ring members 48, 49, carried by the housing 28 and die 7. The material is delivered from each hopper 44 to a feed tube 31, by a screw conveyer 52 in each hopper rotated by a common endless rope drive from a variable speed motor, preferably through a slipping clutch. Each conveyer 52 terminates with a clearance from its feed tube 31, permitting rotation of the feed tube 31 with the shaft 12 upon breakage of the shear pins, and the screw conveyers each have a hollow shaft 53 tapering towards the feed tube 31 and through which compressed air can be discharged, at a nozzle 55, for periodic removal of any material adhering to the feed tube 31 which may also be Heading B5A facilitated by an anti-adhesion coating on the feed tube 31. The material delivered through the feed tubes 31 and 31<SP>1</SP>, respectively falls on to the inner surface of the die 7, and on to the rollers 20 beneath the tube 31<SP>1</SP>. The material preferably comprises a flour product blended with molasses, for animal feed pellets which fall from the mill on to a conveyer means.