GB2137535A - Separator - Google Patents

Abstract

A separator includes an upright drum to receive a continuous supply of a mixture of materials and water. In the resulting fluidised mass lighter materials in the mixture move towards the top of the drum and heavier materials sink towards the bottom of the drum. A plunger controls an opening in the bottom of the drum and is movable in response to signals generated by weighing means for the drum and its contents operable between upper and lower values. In phase with the discharge of water and heavier materials through the bottom opening, water carrying lighter materials surges over the top of the drum.

Description

SPECIFICATION An improved separator The present invention concerns a separator for separating one or more constituents of a mixture from the remainder of the mixture. In particular, the invention concerns a separator for use in mines, quarries, gravel pits and the like for separating undesirable materials from required minerals.

According to the present invention a separator comprises an upright drum to receive the mixture for separating one or more constituents of a mixture from the remainder of the mixture having a bottom discharge opening, means for directing water into the interior of the drum, weighing means for the drum and closure means cooperable with the discharge opening and movable in response to signals generated by the weighing means to alternately open and close the discharge opening.

The invention will be described further, by way of example, with reference to the accompanying drawings; in which: Figure 1 is a diagrammatic elevation, partly in section, of a separator; Figure 2 is a diagrammatic elevation, partly in section, in the direction of arrow A in Figure 1; and Figure 3 is a diagrammatic section, not to scale, through the lower part of the separator.

A separator comprises an upright tapered drum 1 which is mounted on a platform or gantry 2. The drum 1 is supported by at least one load cell 3 which is arranged between the platform or gantry 2 and a collar 4 or the like on the drum. The drum 1 is open at the top and has an opening in the bottom. A channel or trough 5 extends about the top of the drum, the floor of the channel or trough being inclined to fall from a high point to an outlet 6 in the floor. The outlet 6 opens into a compartment 7 having a bottom opening 8 and containing a carrier 9 for a mesh grid 10. The carrier 9 is pivotal about axis 11 and can be releasably secured in one of a number of positions whereby to alter the inclination of the grid 10. Conveniently the grid 10 comprises a number of separate units which are arranged side-by-side on the carrier 9.

A water delivery conduit 12 passes through the wall of the drum 1. Outside the drum the conduit rises to a height above the top of the drum and constitutes an inverted U-bend. A main control valve 13 is included in the conduit 12. A branch conduit 14 having a pressure-operated valve 15 extends from the top of the U-bend to open into the channel or trough 5. A further branch conduit 16 having a manually adjustable valve 17 can extend from the conduit 12 to communicate with one or more conduits 18 which pass through the wall of the drum at a region immediately above the opening in the bottom of the drum. The end of the conduit 12 within the drum is directed towards the bottom of the drum and is located substantially on the axis of the drum.

This end is provided with a flange to which can be secured a distributor 20 for distributing water outwardly towards the wall of the drum. The position of the distributor within the drum can be varied by the insertion or removal of collars 21 between the flange and the distributor.

A plunger 22 is arranged within the drum to cooperate with a seat 23 positioned in the opening in the bottom of the drum. The plunger 22 comprises a body 24 having a chamfered end to cooperate with the seat 23 and a stem 25 terminating in a flange 26 which cooperates with and is releasably secured to a plate 28 carrying a yoke 29. Removable shims 30 can be inserted between the flange 26 and the plate 28 to provide adjustment for the positioning of the plunger on the seat. The plunger is suspended by a link 31 from a cup-shaped flexible diaphragm, conveniently a rubber diaphragm 32. The diaphragm 32 carries a plate 33 having an eye 34 to which the link 31 is attached, the plate 33 being secured to the diaphragm by a backing plate 35. The diaphragm is clamped at its periphery between the rim of a cup-shaped chamber 36 and a clamping ring 37.An aperture 38 is provided in a wall of the chamber 36 to receive a pipe 42 and the chamber 36 is positioned and located within the drum 1 by a support 39 and a support arm 40 which also protects the pipe 42. The interior of the chamber 36 communicates through the pipe 42 with a suction pump 43 by way of a float chamber 44. A solenoid valve 45 is located in a branch 46 from the pipe 42, the valve 45 venting to atmosphere. A non-return valve 47 in the float chamber 44 is operable to permit flow out of the chamber and to prevent entry of air into the chamber.

A pressure relief valve 48 is in communication with the pipe 42. With the solenoid valve 45 open to vent the chamber 36 to atmosphere the diaphragm 32 assumes the full-line position shown in Figure 3 and the plunger body 24 sits on its seat 23 to close the opening in the bottom of the drum 1.

The seat comprises a ring 49 which is mounted in a recess formed in an annular insert 50 removably located in the bottom of the drum. The insert 50 and the opening in the bottom of the drum have cooperating tapered surfaces. The insert 50 is mounted on a frame comprising two arms 52 interconnected at one of their ends by a cross member 53 and pivotally supported at their opposite ends by a spindle 54 carried by brackets 55 fixed to the bottom of the drum. The insert 50 is pivotally mounted on the frame arms 52 by a spindle 56 carried by brackets 57 fixed to the insert. The frame is releasably secured in position to retain the insert in the opening in the bottom of the drum by means of a latch. The latch conveniently can comprise a screw 58 which depends from the base of the drum and having a cooperating wing nut 59.The insert can be removed and replaced to accommodate a range of different seat rings 49 to vary the extent of the bottom opening, and the pivoting of the insert 50 on its frame support assists in its correct positioning in the opening in the bottom of the drum.

In operation, materials to be separated, for example, sand and gravel containing undesirable minerals such as lignite are delivered continuously into the drum by an overhead conveyor system (not shown).

The opening in the bottom of the drum is closed by the plunger 22 and water is delivered into the drum through the pipe 12. The water can be at a pressure of about 1 Kg/cm and a flow rate of about 30 litres/sec. The non-return valve 15 in the branch pipe 14 is normally closed under pressure and opens if a drop in water pressure occurs to prevent the possibility of siphoning of water out of the drum in a return path along the pipe 12.

The materials falling into the drum meet the water issuing from the distributor 20 and as a result the materials are directed towards and accumulate along the wall of the drum. In the resulting fluidised mass the lighter materials such as lignite move upwardly within the drum and the heavier materials sink to the bottom of the drum. Eventually part of the contents of the drum will overflow over the top of the drum into the trough or channel 5.

The load cell 3 is operable between predetermined upper and lower values. When the weight of the drum and its contents reaches the upper value the load cell operates to generate a signal to activate the solenoid valve 45 and the pump 43. The solenoid valve, which is normally open to atmosphere to vent the pipe 42 and the chamber 36, closes and suction is applied to the chamber 36 to cause the diaphragm 32 to assume the dotted outline shown in Figure 3. The diaphragm thus lifts the plunger 22 from its seat 23 to thereby open the opening in the bottom of the drum to allow water and the heavier materials (sand and gravel) to fall out of the drum. if required, water can be directed into the bottom of the drum through the pipes 18 to assist in the discharge and to prevent blockage.The amount of material which is discharged through the bottom of the drum is greater than the amount of material being delivered into the drum and consequently there is a decrease in the weight of the drum and its contents. When the weight reaches a predetermined lower value the load cell operates to deactivate the solenoid valve 45 and the pump 43. The venting to atmosphere of the chamber 36 allows the diaphragm to revert to its original position and the plunger drops on to its seat to close the opening in the bottom of the drum. The link 31 and the chamfered end of the plunger body 24 assist in the correct location of the plunger on the seat 23. The cycle then repeats itself and the plunger will again be lifted from its seat when the weight of the drum and its contents again reaches the upper value determined by the load cell.The upper and lower values of the load cell are adjustable to meet operational requirements. The float chamber 44 is included to protect the pump in the event of a water leak along the pipe 42. Such water can collect in the float chamber and can be drained off through the valve 47 if the level of water in the float chamber is such as to cause the float to close the pipe connection to the pump 43.

In phase with the discharge through the bottom opening, material surging over the rim of the drum into the trough or channel 5 will comprise water carrying the lighter lignite and a certain amount of sand. The discharge falls on to the mesh grids 10 which trap the lignite while allowing the sand and water to fall through and out of the bottom of the compartment 7. As mentioned the angle of inclination of the mesh grids is adjustable to eanble the effective mesh size to be varied.

The separator effectively separates light and heavy solids and is of a robust construction suitable for use in mines, quarries, gravel pits and the like for separating unwanted minerals.

In a modification, instead of venting the interior of the chamber 36 to allow the plunger to fall under its own weight on to its seat, pressure can be applied to the interior of the chamber to thereby create a positive downward push on the plunger. Thus a pneumatic cylinder can be employed to raise and lower the plunger. The air supply to the cylinder for the down stroke of the plunger can be controlled by a spring-return solenoid valve to ensure that the plunger closes the discharge opening in the event of electric power failure.

To avoid the possibility of materials collecting at the bottom of the drum and also to protect the wall of the drum against wear and damage, a removable and replaceable tapered insert, which can be formed from a number of individual parts, can be positioned about the opening in the bottom of the drum to extend to the wall of the drum to channel material into the discharge opening. The tapered insert also guides the plunger into the discharge opening.

Claims (7)

1. A separator for separating one or more constituents of a mixture from the remainder of the mixture comprising an upright drum to receive the mixture having a bottom discharge opening, means for directing water into the interior of the drum, weighing meansforthe drum and closure means cooperable with the discharge opening and movable in response to signals generated by the weighing means to alternately open and close the discharge opening.

2. A separator as claimed in claim 1 in which the weighing means comprises at least one load cell arranged between the drum and a support for the drum.

3. A separator as claimed in claim 1 or 2 including a removable and replaceable tapered insert within the drum about the discharge opening.

4. A separator as claimed in any preceding claim in which the closure means comprises a plunger suspended from a flexible diaphrahgm displaceable in response to pressure changes at the side of the diaphragm remote from the plunger.

5. A separator as claimed in claim 4 including pump means operable in response to the signals generated by the weighing means to effect the pressure changes at the diaphragm.

6. A separator as claimed in any preceding claim including means for varying the extent of the discharge opening at the bottom of the drum.

7. A separator for separating one or more constituents of a mixture from the remainder of the mixture substantially as herein described with reference to and as illustrated in the accompanying drawings.