NZ198138A - Spiral separator for particles in liquid - Google Patents

Description

Priority Defcs(«>: .'"Wa-frl Co?r.p!stQ Gpscifi^ion^Filfd^. ...... c:-": 6-??" "'"'' 3 T JAN 1985''' Publication Dsts: ..••••»• iiii* 24AU6W81 N.Z. No.

NEW ZEALAND Patents Act 1953 COMPLETE SPECIFICATION " A SPIRAL SEPARATOR." INHEED PTY LTD., of Main Street, Murwillumbah, New South Wales, Australia, incorporated under the laws of the State of New South Wales, Australia do hereby declare the invention, for which we pray that a Patent may be granted to us, 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 spiral separator. Spiral separators for wet separation of minerals are well known , such a separator consisting of one or more helical sluices or "spirals" mounted on a central column, a pulp or slurry of water and the minerals to be separated being introduced to the head of each spiral, minerals of higher density or specific gravity tending to travel near to the inner part of the spiral, near to its axis, the less dense minerals travelling along the outer part of the spiral, so that the pulp forms strata, take-offs being provided for drawing off the required minerals, which may be separated into concentrates and tailings, or concentrates, middlings and tailings.

Such conventional spiral separators have take-off arrangements or assemblies which in one form may include a a slot or aperture near the inner part of the spiral separator which may optionally have a splitter operatively associated therewith so as to draw off concentrates from the remainder of the pulp into the interior of the central column. Often as many as three or four of such take-off assemblies were incorporated in each helical turn of the separator and the resulting1' spiral separator was somewhat complex in construction owing to the necessity of forming the slots or apertures in the bottom wall or floor of each helical turn. The take-off assemblies including the splitter blades for use with the slot or aperture were also difficult to manufacture.

The present invention has been devised with the general object of providing a spiral separator which alleviates the above mentioned problems associated with the prior art in being simple in construction and efficient in operation.

The invention provides a spiral separator including an upright column and supported with its axis substantially vertical which is adapted to receive at an upper end thereof a pulp of water and peptides to be separated, said spiral separator including a plurality of helical turns mounted to said upright column wherein there is provided in at least 198138 portion of the spiral separator an inner trough or gutter and an outer channel wherein said trough or gutter and said channel are separated by an upstanding boundary wall having a gap or entrance opening whereby a proportion of the pulp is diverted into the inner trough or gutter.

Preferably the boundary wall is provided with a plurality of gaps or openings throughout its length and optionally adjustable splitters are located within the region of said gaps or openings.

As used in the specification, the term "pitch" refers to the vertical distance between adjacent turns of the separator at corresponding locations.

BRIEF DESCRIPTION OF THE DRAWINGS One embodiment of the invention is shown, by way of illustrative example only, in the accompanying drawings, wherein: FIG. 1 is a side elevation of a single-start spiral separator according to the invention; FIG 2 is a plan view of the separator; FIG 3 is a plan view of part of an intermediate turn of the separator; FIG 4 is a plan view of part of an intermediate turn of the separator; FIG 5 is a sectional view along line 5-5 in FIG 2; FIG 6 is a sectional view along line 6-6 in FIG 2; FIG 7 is a sectional view along line 7-7 in FIG 3; and, FIG 8 is a sectional view along line 8-8 in FIG 4.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The spiral separator illustrated includes a single spiral 10 mounted about an upright tubular column 11.

Ordinarily the separator would be of "two-start" type, with two identical spirals 10 mounted about the column 11, their heads and discharge ends being angularly spaced apart, but for clarity of illustration the single spiral only is shown.

At the head of the separator pulp is discharged through a feed pipe 12 into a recess or downward extension 13 in the separator bottom the pulp in the bottom of this recess minimising frictional wear of the separator bottom at this position. As shown in FIG 2, the radius of the separator at its head is reduced, thus enabling the installation of two separators on the central column 11 without fouling.

The first turn of the separator is formed with a high and wide boss 14 about the column, as shown in FIGS 2 and 5, constricting the flow of pulp into a narrow and deep channel or trough 15 having an inner wall and outer wall as shown. Within the first turn of the separator, this boss gradually decreases in width and height to become indistinguishable from the inner wall, so that the channel or trough 15 is progressively widened and decreased in depth, as shown inFIGS 2 and 6. The first turn of the separator, as shown in FIG 1, is of small pitch, say about 24cm (the maximum inside radius of the separator being 29cm);but the pitch of the second turn is increased gradually to about 35cm.

In the third turn of the separator, the pitch is v i somewhat decreased, say to about 32cm and the inner wall of the channel 15 may be increased in height to form a gradually rising boundary wall 16 spaced from the inside of the separator to form an.'inner trough 17 dividing the denser or finer materials from the coarser or less dense. This wall continues down the separator, gradually increasing in depth and, at about the end of each turn, as shown in FIGS 3 and 4, it is formed with a break or gap 18, the up-stream wall end curving in, the downstream wall end turning out, so that denser or finer minerals travelling close to the outside of the wall 16 will be guided into the inner trough 17. This is facilitated by a lead-in depression 19 in the separator bottom up-stream of the gap 18 and outside the wall 16.

The fourth turn and most of the fifth turn of the separator may be of about 30cm pitch; but the final part of the I 198138 fifth or final turn is increased in pitch and decreased in radius to increase the velocity of the final run of the pulp. In this final part of the separator, a further dividing wall 20 is developed so that the pulp leaving the sluice is divided 5 into denser or finer particles from the innermost trough 17, middlings passing between the walls 16 and 20, and coarser or less dense fractions from the outermost part of the spiral.

If required, adjustable splitters (not shown) may be placed at locations 20A shown in FIG 4.

Spiral separators according to the invention will be found to be very efficient in operation, and therefore enabling the effective separation of concentrates from middlings and tailings at a minimal cost of manufacture.

In a second aspect of the invention, there is provided 15 a spiral separator including an upright column and supported with its axis substantially vertical which is adapted to receive at an upper end thereof a pulp of water and particles to be separated, said spiral separator also including a plurality of helical turns mounted to said upright column 20 wherein at least in a top portion of the separator there is provided a channel located on an outer part of the separator which is initially narrow and deep and becomes progressively wider to enable the particles to obtain or maintain an initial velocity so as to maintain the flow of pulp without the coarser 25 and/or less dense particles becoming stationary or stranding and wherein the coarser and/or less dense particles may be retained in an outer section of the channel and the finer and/or denser particles may move toward and inner section of the channel and be retained in said inner section. 30 Spiral separators according to the second aspect of 198138 the invention will be found to be very efficient in operation, and therefore enabling the effective wet-separation of asbestos which, because of its carcinogenic nature may present serious health dangers if processed dry, the pulp with high water 5 content effectively preventing any likelihood of danger from air-borne asbestos particles.

The second aspect of the invention, as well as being useful in the separation of asbestos from crushed rock will, in fact, be found to be extremely useful in the classification of 10 low density particles generally and in particular in the washing of fine coal particles from coal ash. It also may be used in the classification of low grade tin ore wherein the low grade particles or debris (sometimes called gangue) will move to the outer part of the channel unlike the other two 15 examples referred to above wherein the debris will move to the inner part of the channel.

In particular in relation to this aspect of the invention, it is found that the rapid flow of the pulp into the deep and narrow channel 15 ensures that the coarser and/or less 20 dense particles such as asbestos or coal, maintained in suspension'without any tendency to stranding of the particles, and the gradual or progressive widening of the channel 15 and decreasing of its depth, facilitates the finer and/or denser particles moving toward the inner part of channel 15 after 25 being initially evenly dispersed throughout the pulp. At the same time the coarser and/or less dense particles may be retained in the outer part of channel 15. 198138

Claims (9)

WHAT WE CLAIM IS:

1. A spiral separator including an upright column and supported with its axis substantially vertical which is adapted to receive at an upper end thereof a pulp of water and particles to be separated, said spiral separator including a plurality of helical turns mounted to said upright column wherein there is provided in at least portion of the spiral separator an inner trough or gutter and an outer channel wherein said trough or gutter and said channel are separated by an upstanding boundary wall having a gap or entrance opening whereby a proportion of the pulp is diverted into the inner trough or gutter.

2. A spiral separator as claimed in claim J. wherein said gap or entrance opening is located at an upstream end of said upstanding boundary wall.

3. A„spiral separator as claimed in claim 1 or 2 wherein said boundary wall is provided with a plurality of gaps or openings throughout its length.

4. A spiral separator as claimed in claim 3 wherein there are provided adjustable splitters within the region of said gaps or openings.

5. A spiral separator as claimed in claim 1 wherein the channel has an outer wall which is substantially uniform in height.

6. A spiral separator as claimed in any preceding claim wherein the channel has a base wall or floor which inclines slightly downwardly relative to the axis of the separator.

7. A spiral separator as claimed in claim 6 wherein the base wall or floor becomes progressively less steep throughout at least part of the length of the channel.

8. A spiral separator including an upright column and supported with its axis substantially vertical which is adapted to receive at an upper end thereof a pulp of water and particles «%\to be separated, said spiral separator also including a plurality ^ \ ^ &f helical turns mounted to said upright column wherein at least in a top portion of the separator there is provided a channel $5^Located on an outer part of the separator which is initially narrow and deep and becomes progressively wider to enable the particles to obtain or maintain an initial velocity so as to maintain the flow of pulp without the coarser and/or less dense particles becoming stationary or stranding and wherein the coarser and/or less dense particles may be retained in an outer section of the channel and the finer and/or denser particles may move toward an inner section of the channel and be retained in said inner section.

9. A spiral separator as claimed in claim 1 substanti ally as herein described with reference to the accompanying drawings. INHEED PTY LTD By Their Attorneys HENRY HUGHES LIMITED By: