GB1569504A - Rotary drum separator - Google Patents

Description

(54) ROTARY DRUM SEPARATOR (71) I, CLAUD STOCKTON, a British Subject of S.A.E. House, 3 Gate Lane, Boldmere, Sutton Coldfleld, West Midlands, B73 STR, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement: - This invention relates to a rotary drum separator comprising a drum having a perforated wall and an inwardly directed helical screw formation on the internal surface of the wall, the drum being rotatably mounted and being rotatable about a substantially horizontal axis so as to feed material axially through the drum for separation according to size through the perforations.

According to the invention, a rotary drum separator of the aforesaid type is modified by providing a plurality of inwardly directed lifter bars on the internal surface of the drum so as to extend substantially longitudinally of the drum axis and to lie on paths that intersect the helical screw formation, the lifter bars themselves extending along helical paths of the same hand as, but of a longer pitch than, the helical screw formation.

These lifter bars serve to disturb the bed of material that forms in the bottom of the drum by lifting this material around the circumference of the drum, the material thereby being mixed for better separation.

Also, the lifter bars help feed the material axially along the drum to give a more controlled separation rate.

Preferably, the drum is started by a variable speed d.c. motor that enables the speed of the drum to be varied to suit different kinds of materials being separated.

The invention will now be described by way of example with reference to the accompanying drawings in which: - Figure 1 is a side elevation of a rotary drum separator according to the invention; Figure 2 is a plan view of part of the separator of Figure 1; and Figure 3 is an end view of the drum of the separator of Figures 1 and 2.

The illustrated rotary drum separator comprises an open ended drum 1 that rests with its axis horizontal, on two pairs of rollers 2 that are mounted in a fixed frame 3 and each engage one of two raised tracks 4 provided around the outside of the drum at its ends so that the drum can rotate about its axis on said rollers. A variable speed d.c. motor 5 (Figure 2) is mounted on the frame 3 alongside the drum and its drive shaft 6 is coupled to the drum via a belt drive comprising a pulley 7 mounted on the frame 3 and a belt 8 that passes round the pulley 7 and a pulley 9 provided around the outside of the drum. Pairs of rollers 10 are mounted on the frame 3 at each end of the drum so as to engage fiat rings 11 provided around the ends of the drum, thereby locating the drum against movement in a longitudinal direction.

The drum 1 has a perforated side wall 12 carrying an inwardly directed flange 13 on its inner surface that extends along a helix from one end to the other. Four inwardly directed lifter bars 14 are also mounted on the inner surface of the wall 12 and each extends from one end of the drum to the other. The lifter bars 14 all extend parallel to one another along helical paths with the same handed thread as the helical flange 13, but the pitch of the lifter bars 14 is much longer than that of the helical flange 13. The lifter bars 14 are equi-angularly spaced around the wall 12 and project inwards to the same extent as the helical flange 13.Typically, the lifter bars may have an angle of 5 degrees with the axis of the drum as seen in Figure 1 so that they have only a fraction of a turn along the length of the drum while the helical flange screw has several turns.

Material that is to be separated according to size is fed into one end of the drum from a hopper 15 and is fed along the drum through the screw action of the flange 13 and lifter bars 14 as the drum is rotated by the motor 5, the drum rotating in the same sense as the hand of the helical flange 13 as seen from the same end of the drum.

Smaller material passes through the perforations in the drum wall 12 into the collector bins 16 beneath the frame 3, and larger material is fed out of the opposite end of the drum from the feed hopper 15 into a collector bin 17. The portions of the lifter bars 14 which extend between the last turns of the helical flange 13 at said opposite end of the drum, retain a certain depth of material in the drum, which material is therefore sieved more efficiently by the perforations in the side wall of the drum before passing over the lifter bars into the bin 17.

A rotary drum separator according to the invention is particularly suitable for use with dry material such as swarf, steel bearings and chopped rubber.

Typically, the motor enables the drum speed to be varied from 0 to 36 r.p.m. to suit the different kinds of material being separated.

WHAT I CLAIM IS: - 1. A rotary drum separator comprising a drum having a perforated wall and an inwardly directed helical screw formation on the internal surface of the wall, the drum being rotatably mounted and being rotatable about a substantially horizontal axis so as to feed material axially through the drum for separation according to size through the perforations, and a plurality of inwardly directed lifter bars being provided on the internal surface of the drum so as to extend substantially longitudinally of the drum axis and to lie on paths that intersect the helical screw formation, the lifter bars themselves extending along helical paths of the same hand as, but of a longer pitch than, the helical screw formation.

2. A separator as claimed in claim 1 in which the lifter bars are generally parallel to one another.

3. A separator as claimed in claim 2 in which the lifter bars are equi-angularly spaced around the perforated wall.

4. A separator as claimed in any one ot the preceding claims in which the helical screw formation has a plurality of turns and the lifter bars each has a fraction of a turn along the length of the drum.

5. A separator as claimed in any one of the preceding claims in which the lifter bars project inwardly of the perforated wall by substantially the same amount as the helical screw formation.

6. A separator as claimed in any one of the preceding claims in which the drum is rotated by variable speed drive means.

7. A separator as claimed in claim 6 in which the drive means comprises a variable speed d.c. motor.

8. A separator as claimed in claim 7 in which the motor rotates the drum via a belt drive, the belt passing around the drum.

9. A rotary drum separator substantially as herein described with reference to the accompanying drawings. ~ ~~

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (9)

**WARNING** start of CLMS field may overlap end of DESC **. along the length of the drum while the helical flange screw has several turns. Material that is to be separated according to size is fed into one end of the drum from a hopper 15 and is fed along the drum through the screw action of the flange 13 and lifter bars 14 as the drum is rotated by the motor 5, the drum rotating in the same sense as the hand of the helical flange 13 as seen from the same end of the drum. Smaller material passes through the perforations in the drum wall 12 into the collector bins 16 beneath the frame 3, and larger material is fed out of the opposite end of the drum from the feed hopper 15 into a collector bin 17. The portions of the lifter bars 14 which extend between the last turns of the helical flange 13 at said opposite end of the drum, retain a certain depth of material in the drum, which material is therefore sieved more efficiently by the perforations in the side wall of the drum before passing over the lifter bars into the bin 17. A rotary drum separator according to the invention is particularly suitable for use with dry material such as swarf, steel bearings and chopped rubber. Typically, the motor enables the drum speed to be varied from 0 to 36 r.p.m. to suit the different kinds of material being separated. WHAT I CLAIM IS: -

1. A rotary drum separator comprising a drum having a perforated wall and an inwardly directed helical screw formation on the internal surface of the wall, the drum being rotatably mounted and being rotatable about a substantially horizontal axis so as to feed material axially through the drum for separation according to size through the perforations, and a plurality of inwardly directed lifter bars being provided on the internal surface of the drum so as to extend substantially longitudinally of the drum axis and to lie on paths that intersect the helical screw formation, the lifter bars themselves extending along helical paths of the same hand as, but of a longer pitch than, the helical screw formation.

2. A separator as claimed in claim 1 in which the lifter bars are generally parallel to one another.

3. A separator as claimed in claim 2 in which the lifter bars are equi-angularly spaced around the perforated wall.

4. A separator as claimed in any one ot the preceding claims in which the helical screw formation has a plurality of turns and the lifter bars each has a fraction of a turn along the length of the drum.

5. A separator as claimed in any one of the preceding claims in which the lifter bars project inwardly of the perforated wall by substantially the same amount as the helical screw formation.

6. A separator as claimed in any one of the preceding claims in which the drum is rotated by variable speed drive means.

7. A separator as claimed in claim 6 in which the drive means comprises a variable speed d.c. motor.

8. A separator as claimed in claim 7 in which the motor rotates the drum via a belt drive, the belt passing around the drum.

9. A rotary drum separator substantially as herein described with reference to the accompanying drawings. ~ ~~