Classifying – separating – and assorting solids – Magnetic – Paramagnetic
Patent
1986-01-08
1987-05-12
Sever, Frank
Classifying, separating, and assorting solids
Magnetic
Paramagnetic
209459, 210322, 2105121, B03B 304
Patent
active
046647899
DESCRIPTION:
BRIEF SUMMARY
CROSS REFERENCE TO RELATED APPLICATION(S)
This U.S. application stems from PTC International Application No. PCT/AU85/00080 filed Apr. 15, 1985.
The present invention relates to a spiral separator adapted for separating particles in a stream of such particles according to their respective densities and/or sizes.
Conventionally spiral separators comprise a helical trough normally supported by a central pillar or column, The trough is conventionally of a cross-sectional shape that includes a base portion adjacent the central pillar or column and a wall portion at the radial extremity of the trough. In some cases there is a smooth arcuate transition between the base portion and the wall portion while in other cases there is a clear angular disjunction therebetween. The efficiency of separation of materials according to their density and particle size will depend upon the pitch of the helical trough and to a lesser extent the means used to introduce a slurry onto the trough and the cross-sectional shape of the trough. The splitters used to split the stream flowing off the trough into fractions also contribute to the efficient operation of the spiral separator.
The conventional spiral separators also suffer from a number of disadvantages due to their mode of construction. In the first place for the flange on the radially inner edge of the trough to be effectively connected to the central column, which is normally done with rivets, it is necessary to space the troughs apart sufficiently for an operator to reach between the troughs. This means there is a severe limit to the number of troughs which may be accommodated on one column. The normal number of troughs on a column being two or three. Conventional spiral separators introduce the slurry to be separated vertically donwardly into a feed box from where it flows onto the trough. The depth of the feed box has itself limited the number of troughs which may be nested together. This problem is made worse by the fact that the outer wall of the trough preferably extends upwardly at a steep angle to the horizontal and adjacent troughs are thus in much closer juxtaposition at their outer edges than they are at their points of contact with the column. Secondly it is difficult to obtain access to the troughs from their outer edges if it is desired to wash them clean. Such washing may be required to clear obstructions in a trough or because a different material is to be classified in the spiral separator. Thirdly it can be difficult to accurately position the troughs on the central column. Accurate positioning is necessary to maintain the trough at the desired pitch to bring about the desired separation of the particles in the slurry stream.
The present invention is in a first aspect directed to spiral separators which substantially avoid the above problems and which allow a greater number of troughs to be supported in coaxial array than has previously been possible.
The present invention consists in its first aspect in a spiral separator comprising at least one substantially helical trough having a cross sectional shape comprising a base portion, an upwardly directed wall portion radially outwardly of the base portion and an upwardly directed lip radially inwardly of the base portion, characterised in that the wall portion is connected to one or more support members positioned radially outwardly of the wall, and in that the lip is free and unconnected, directly, to any supporting means, the lip serving to define an axially extending space within the separator.
The troughs and the support members preferably are made from glass reinforced plastic in a suitable mould, however, it will be appreciated that either could be made from other material and in other ways. In particular the support members may be made of extruded aluminium.
It is strongly preferred that the troughs be sufficiently flexible that the pitch thereof may be varied at the time the trough is connected to the support members. The trough is preferably made of a fibre reinforced synthetic plastics material wi
REFERENCES:
patent: 2431559 (1947-11-01), Humphreys
patent: 2431560 (1947-11-01), Humphreys
patent: 2700469 (1955-01-01), Humphreys
patent: 3891546 (1975-06-01), Humphreys
Andrews John R. G.
Lees Jeremy J.
Pryor Murray H.
Minpro Pty. Limited
Sever Frank
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