GB2086265A

GB2086265A - Jig washing plant

Info

Publication number: GB2086265A
Application number: GB8132974A
Authority: GB
Original assignee: Babcock Minerals Engineering Ltd
Current assignee: Babcock Minerals Engineering Ltd
Priority date: 1980-10-31
Filing date: 1981-11-02
Publication date: 1982-05-12
Also published as: GB2086265B

Abstract

In a raw coal or ore mixture washing plant, the mixture is fed onto in inclined perforate bed plate 20 in a wash box 2 containing water. The wash box is compartmented and centrally partitioned. Cyclical water flow through the bed plate 20 is effected by cyclically applying superatmospheric air pressure through a valve 24 to the chamber 22. Adjustable hydrovanes 70, 72 are positioned at the bases 66, 68 of diverging baffles 54, 56 in the chamber 14 below the bed plate to proportion the water flow through the bed plate. <IMAGE>

Description

SPECIFICATION Improvements in or relating to washing plant This invention relates to washing plant for effecting separation of coal or ore from a mixture of coal or ore and other particulate material mined therewith in which the mixture is fed onto an inclined perforate washing bed in a wash box and is there subjected to an alternating upward and downward flow of water to effect separation of the coal or ore from the mixture, the separated components being discharged over weirs entrained in the water or passing through the perforate washing bed to a lower region of the wash box for removal by a screw conveyor.The wash box is divided into compartments transverse to the direction of progression of the mixture from inlet to final outlet and water flows in the respective compartments are produced by applying superatmospheric air pressure to one side of a partition extending centrally of the compartment, in the direction of progression of the mixture, to produce an upward flow of water to the other side of the partition and through the perforate washing bed.

It has been found that such plant is liable to suffer from uneven distribution of material across the washing bed.

According to the present invention there is provided washing plant for effecting separation of coal or ore from a mixture of coal or ore and other particulate material including a wash box having side walls and compartmented in the direction of progression of the mixture from inlet to final outlet with each compartment having an upright partition extending in the said direction and spaced from a base portion of the compartment with a perforate washing bed plate being disposed to one side of the partition and air supply means being disposed to the other side thereof, in which a plurality of chambers are formed by upright baffles disposed subjacent the washing bed in at least one of the compartments each upright baffle having an adjustable hydrovane hinged to a lower extremity thereto.

The invention will now be described, by way of example, with reference to the accompanying, partly diagrammatic, drawings, in which: Figure 1 is a sectional side elevation of a coal washing plant; and Figure 2 is a sectional end elevation taken at the line Il-Il on Figure 1.

As shown, the coal washing plant includes a wash box 2 of trough form having side walls 4 and 6 diverging upwardly from a central base channel 8. End walls 10 of the wash box are upright and seven upright division 12 walls extending parallel to the end walls 10 serve to divide the wash box into compartments 14. An upright partition 16, slightly offset from centre, extends the length of the wash box with a lower extremity 1 8 spaced from the base of the wash box. A perforate washing bed plate 20 extends the length of the wash box to one side of the partition and is upported on upper edge portions of the division walls 12.To the other side of the partition the wash box is provided with a cover plate 21 extending between the partition 1 6 and the adjacent side walls 6, the division walls 12 extending upwardly to connect with the cover plate and form air tight chambers 22. Valved air supply and exhaust means 24 are connected to communicate with the interiors of respective air tight chambers 22.

The washing bed plate 20 is divided into an initial portion 26 adjustable in inclination between horizontal and 80 to horizontal and extending over two compartments. At the discharge end of the initial portion 26 there is provided a gate 28 and a weir 30, each adjustable in level, permitting egress of separated material to a discharge compartment 32, the remaining material passing over a bridge plate 34 above the discharge compartment to a main portion 36 of the washing bed plate 20.

The main portion of the washing bed plate 20 extends, at a slight inclination to the horizontal, over four compartments 14 and discharges separated material under an adjustable gate 38 and over an adjustable weir 40 to a collection compartment 42. The remaining material, consisting largely or wholly of coal or ore passes over a bridge plate 44 and is discharged to an outlet chute 46.

Separated material is removed from the discharge compartment 32 and the collection compartment 42 by means of draining bucket elevators 48, 49 and from the base channel 8 of the compartments 14 by means of screw conveyors 50, 52.

Each of the compartments 14 subjacent the washing bed plate 20 is provided with two, equally-spaced first and second baffles 54, 56 forming upwardly diverging chambers 58, 60, 62 respectively between the wall of the wash box and the first baffle 54, between the first baffle 54 and the second baffle 56 and between the second baffle 56 and the upright partition 16. A nosing 64 is provided on the upright partition 1 6 to form an entry throat adjacent the lower ends 66, 68 of the first and second baffles 54, 56 having a width substantially equal to that between the upright partition 1 6 and the side walls 6 at that level.

Hydrovanes 70, 72 are respectively pivoted at the lower ends 66, 68 of the first and second baffles 54, 56 and are pivotable manually by means of rods 74, 76 connected through pinned joints and bell crank levers 78, 80 to the hydrovanes, lengths 82, 84 of the rods extending in a pocket upright formed 86 on the wall 4. The hydrovanes are pivotable to either side of a position in alignment with the associated baffle.

In operation, the plant is supplied with a raw coal mixture in particulate form from which it is desired to separate coal. The mixture is passed along the washing bed plate 20 and the valved air supply and exhaust means 24 to the respective compartments activated to produce a pulsating flow of water through the washing bed. Due to the differing relative densities of the particles separation of the various materials is effected as the material progresses along the washing bed such that coal alone is discharged from the outlet chute.

It has been found that the raw coal mixture is liable to be distributed unevenly across the width of the washing bed plate 20 tending to impair the separation effect and once an uneven distribution arises it is difficult to correct since the flow of water tends to reinforce the uneven distribution.

However, by adjusting the hydrovanes 70, 72 the proportioning of the flow of water through the washing bed plate is varied by restricting the cross flow area at the base of one of the chambers 58, 60, 62 and increasing the cross flow area at the base of the adjoining chamber. Thus on detecting an uneven distribution across the width of the washing bed the hydrovanes 70, 72 of the appropriate compartment 14 or compartments are adjusted to vary the water flow through the chambers 58, 60, 62 and thereby tend to correct the distribution.

It will be appreciated that more than two baffles and hydrovanes may be provided for each compartment to enable the distribution to be controlled more closely, if necessary.

it will also be appreciated that in some washing plant it will be sufficient to adjust the hydrovanes 70, 72 during commissioning of the plant to give an optimum distribution of flow and then to fix the hydrovanes in those positions.

Even with the hydrovanes aligned with the associated baffles, the baffles exert a unifying influence on the flow in that they tend to restrict water flow other than in a direction perpendicular to the washing bed. The diverging form of the chambers also tends to encourage generally even flows of water between the chambers.

Claims

1. Washing plant for effecting separation of coal or ore from a mixture of coal or ore and other particulate material including a wash box having side wails and compartmented in the direction of progression of the mixture from inlet to final outlet with each compartment having an upright partition extending in the said direction and spaced from a base portion of the compartment with a perforate washing bed plate being disposed to one side of the partition and air supply means being disposed to the other side thereof, in which a plurality of chambers are formed by upright baffles disposed subjacent the washing bed in at least one of the compartments each upright baffle having an adjustable hydrovane hinged to a lower extremity thereof.

2. Washing plant as claimed in Claim 1, wherein the chambers diverge upwardly.

3. Washing plant as claimed in Claim 1 or Claim 2, wherein each hydrovane is provided with a linkage for effecting movement thereof including a rod extending laterally to a bell-crank and an upright rod connected to the bell-crank extending in a pocket adjacent one of the side walls.

4. Washing plant arranged and adapted to operate substantially as hereinbefore described with reference to the accompanying drawings.