GB1588490A - Sand separator - Google Patents

Description

(54) IMPROVED SAND SEPARATOR (71) We, NATIONAL RESEARCH DE VELOPMENT CORPORATION, a British Corporation established by Statute, of Kingsgate House, 6674Victoria Street, London, S.W.1, 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 is a modification of the sand separator described and claimed in Patent Application 12655/77 (Serial No.

1576469).

During the step when that separator is receiving the suspending liquid without .par tides, various densities of particles separate out down the slope. This phenomenon is exploited in the present invention by modifying feature (e), and optionally features (b) and (c), of that separator, in the following ways: Feature (b): The sloping directions may be in line, the upper edges of the sloping surfaces being adjacent and the surfaces sloping downwardly away from each other.

Feature (c): The lower ends of the surfaces may each have a gutter affixed to its respective surface, the gutters drain- ing into common tailings collection means.

Feature (e): The change in shear con ditions is arranged to be achieved in that the timing means is arranged to initiate a tilting of the surface, the line on which the surface pivots being parallel to the sloping direction. The collecting arrange ments are not arranged to receive differ ent time-intervals of particles in different compartments, but lie alongside the (when tilted) lower edge of each surface parallel to the sloping direction and are partitioned to collect separately particles which at the instant of tilting have travelled different distances down the sloping direction.

Preferably, each surface has full-length riffles substantially parallel to the hori zontal motion.

Preferably, the riffles are in groups separated along the sloping direction by unriffled portions of the surface.

Preferably the partitioning of the col lecting arrangements corresponds with the grouping of the riffles.

The riffles may be i" to 9" wide by 10 thou to 100 thou (thousandths of an inch) high, spaced by 1 to 3 inches.

The invention extends to a method of using the present separator and to the particles separated by it.

The invention will now be discussed by way of example.

The words 'slope' and 'tilt' are throughout used to designate different directions. The invention is illustrated by the accompanying drawing.

With the sideways tilting, riffles do assist and may be in say three groups 71, 72 and 73 or 3-5 each, the groups 71 being intended to retain high-grade concentrate (for which low riffles, e.g. 30 thou high, are suitable), the groups 72 medium-grade concentrate (slightly higher riffles-the riffles generally should be slightly higher than the coarsest particles to be collected thereat) and the groups 73 middlings respectively.

A sideways flushing water supply 76 is of course provided to allow the particles to be rinsed off when the surface is tilted, to say 400, consequent on which the upturned lips 74 at the edges of the surfaces parallel to the sloping direction should be of a somewhat smaller angle of upturn, say 300.

The launder 75- which collects the particles during the sideways tilting is partitioned corresponding to the groups 71, 72 and 73 of riffles. The launder may either be common to both surfaces (or stacks) with separate feeds of flushing water, or said feeds may be common, with separate launders. Where the whole surface is riffled, the partitioning 75a of the launders may be made movable, so that fractions of any desired range of characteristics may be collected separately.

The change in shear conditions in 12655/ 77 (Serial No. 1576469) may be a rapid tilt perpendicular to the sloping direction, addi tional suspending fluid being applied along the side which has been tilted up. The 14 slope interferes relatively little if the tilt is around 400, and may thus conveniently be left alone.

Turning to the riffles, these are applied to the deck surfaces and extend the full length parallel to the horizontal motion. Their height and spacing are related to the feed characteristics but are usually grouped as above. Their heights and widths are as above. The riffle spacing, conveniently and the number of riffles in each group are chosen to provide sufficient catchment appropriate to the amount of liberated or free heavies arriving on the surface during a feed period.

The riffle dimensions being tailored to their proposed function, the second group of riffles may for example be required to reproduce the first group and be of the same height and spacing, or they may be successively higher down the slope to catch the intermediate density particles (which are usually of larger size). The tilt now being sideways (rather than as in 12655/77 (Serial No. 1576469) being a mere increase in the tilt used in the feed cycle, with all products discharging over the same lip), it is now possible to collect separately particles of different grades (which previously were all mixed up), so as to equal the performance of a shaking table in which high grade products are made.

WHAT WE CLAIM IS: - 1. A separator as claimed in any of claims 1 to 7, or in any of claims 9 to 14 when appendant to any of claims 1 to 7, of Patent Application 12655/77 (Serial No.

1576469), with the modifications to feature (e) that the said change in shear conditions is arranged to be achieved in that the timing means is arranged to initiate a tilting of the surface, the line on which the surface pivots being parallel to the sloping direction, and that the collecting arrangements are not arranged to receive different time-intervals of particles in different compartments, but lie alongside the (when tilted) lower edge of each surface parallel to the sloping direction and are partitioned to collect separately particles which at the'instant of tilting have travelled different distances down the sloping direction.

2. A separator according to' claim' '1 hereof, wherein feature (b) is modified in that the sloping directions are in line, the upper edges of the sloping surfaces being adjacent and the surfaces sloping downwardly away from each other.

3. A separator according to claim 1 or 2 hereof, wherein feature (c) is modified in that the lower ends of the surfaces each have a gutter affixed to its respective surface, the gutters draining into common tailings collection means.

4. A separator according to any preceding claim hereof, wherein each surface has full-length riffles substantially parallel to the horizontal motion.

5. A separator according to claim 4 hereof, wherein the riffles are in groups separated along the sloping direction by unriffled portions of the surface.

6. A separator according to claim 5 hereof, wherein the partitioning of the collecting arrangements corresponds with the grouping of the riffles.

7. A separator according to claim 4, 5 or 6 hereof, wherein the riffles are k to i inch wide.

8. A separator according to any of claims 4 to 7 hereof, wherein the riffles are 1 to 3 inches apart.

9. A separator according to any of claims 4 to 8 hereof, wherein the riffles are 0.01 to 0.1 inches high.

10. A method of separating particles of different densities, comprising using a separator according to any preceding claim hereof.

11. Particles separated from other particles by the method of claim 10 hereof.

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

Claims (11)

**WARNING** start of CLMS field may overlap end of DESC **. tional suspending fluid being applied along the side which has been tilted up. The 14 slope interferes relatively little if the tilt is around 400, and may thus conveniently be left alone. Turning to the riffles, these are applied to the deck surfaces and extend the full length parallel to the horizontal motion. Their height and spacing are related to the feed characteristics but are usually grouped as above. Their heights and widths are as above. The riffle spacing, conveniently and the number of riffles in each group are chosen to provide sufficient catchment appropriate to the amount of liberated or free heavies arriving on the surface during a feed period. The riffle dimensions being tailored to their proposed function, the second group of riffles may for example be required to reproduce the first group and be of the same height and spacing, or they may be successively higher down the slope to catch the intermediate density particles (which are usually of larger size). The tilt now being sideways (rather than as in 12655/77 (Serial No. 1576469) being a mere increase in the tilt used in the feed cycle, with all products discharging over the same lip), it is now possible to collect separately particles of different grades (which previously were all mixed up), so as to equal the performance of a shaking table in which high grade products are made. WHAT WE CLAIM IS: -

1. A separator as claimed in any of claims 1 to 7, or in any of claims 9 to 14 when appendant to any of claims 1 to 7, of Patent Application 12655/77 (Serial No.

1576469), with the modifications to feature (e) that the said change in shear conditions is arranged to be achieved in that the timing means is arranged to initiate a tilting of the surface, the line on which the surface pivots being parallel to the sloping direction, and that the collecting arrangements are not arranged to receive different time-intervals of particles in different compartments, but lie alongside the (when tilted) lower edge of each surface parallel to the sloping direction and are partitioned to collect separately particles which at the'instant of tilting have travelled different distances down the sloping direction.

2. A separator according to' claim' '1 hereof, wherein feature (b) is modified in that the sloping directions are in line, the upper edges of the sloping surfaces being adjacent and the surfaces sloping downwardly away from each other.

3. A separator according to claim 1 or 2 hereof, wherein feature (c) is modified in that the lower ends of the surfaces each have a gutter affixed to its respective surface, the gutters draining into common tailings collection means.

4. A separator according to any preceding claim hereof, wherein each surface has full-length riffles substantially parallel to the horizontal motion.

5. A separator according to claim 4 hereof, wherein the riffles are in groups separated along the sloping direction by unriffled portions of the surface.

6. A separator according to claim 5 hereof, wherein the partitioning of the collecting arrangements corresponds with the grouping of the riffles.

7. A separator according to claim 4, 5 or 6 hereof, wherein the riffles are k to i inch wide.

8. A separator according to any of claims 4 to 7 hereof, wherein the riffles are 1 to 3 inches apart.

9. A separator according to any of claims 4 to 8 hereof, wherein the riffles are 0.01 to 0.1 inches high.

10. A method of separating particles of different densities, comprising using a separator according to any preceding claim hereof.

11. Particles separated from other particles by the method of claim 10 hereof.