US2789568A - Washer devices for coal or other granular material - Google Patents

Description

April 23 1957 HlRsT 2,789,568

WASHER DEVICES FOR COAL OR OTHER GRANULAR MATERIAL Filed March 16, 1953 4 Sheets-Sheet 1 A. A. HIRST 2,789,568

WASHER DEVICES FOR COAL OR OTHER GRANULAR MATERIAL April 23, 1957 4Sheets-Sheet2 Filed March 16, 1953 FIG.2.

April 23, 1957 A. A. HlRS-T 2,789,568

WASHER DEVICES FOR COAL OR OTHER GRANULAR MATERIAL Filed March 16, 1953 4 Sheets-Sheet 5 no. 3A.

' FIG. 3.

il/W A. A. HIRST April 23, 1957 WASHER DEVICES FOR COAL OR OTHER GRANULAR MATERIAL Filed March 16, 1953 4 Sheets-Sheet 4 Ufiied etePee T WASHER DEVICES FoRooAL OR OTHER GRANULAR MATERIAL Application March 16, 1953, seam. 342,658 12 Claims. 01. 134-56 This invention concerns washer devices for coal or other granular material of the kind in which a pulsating now of water is caused to take place through a grid over which is maintained a flow ofwater containing particles of the material and refuse whereby a bed of refuse is caused to collect on the grid.

An object of the invention is to provide means for indicating variations in and controlling the depth of the refuse bed.

According to the invention, means operated by the pulsating flow of water in a washer of the kind described and responsive to variations in the resistance presented by the refuse bed to the pulsating flow of water are caused to operate an air pump and to give rise to corresponding variationsin the pressure and/ or volume of air discharged by said pump. Since the said resistance varies with the depth of the refuse bed, the said variations in pressure or volume are an indication of the depth of the bed and therefore by means of a suitably calibrated pressure or volume indicator, the depth of the bed may be read off directly.

in one convenient arrangement the air pump may comprise a tube communicating with the space beneaththe refuse bed and adapted to contain 'a pulsatingfcolurnn of water, a leak-off or snift in the air pump discharge 'conduit and a pressure gauge for indicating the airpressure maintained by the pump against the leak. The pump discharge conduit may alternatively or in addition be eonnected to a controller fora conventional refuse extractor which controller may operate directly or through relay apparatus. I l t b By way of example one "form'o f the invention isherein described with reference to the accompanying "drawings in which: g 3

Figure 1 is a'diagramm'ati c representationof a complete y m; v. t

Figure 2 is a detail elevation, partly insection, ofnonreturn inlet and outlet valves suitable for use in the system of Figure 1; p V

Figure 3 is a sectional elevation of a leak-01f valve suitable for use in thatsystem,and V Figure 3A is a 'cross-sectionof a rod forming part of the leak-off valve of Figure 3. n I

Figure 4 is a diagrammatic sectional elevation of a pressure-responsive device "suitable for use in the system of Figure 1, and

Figure 5 is a diagrammatic elevation of an alternative form of the device illustrated in Figure 4.

, Figure 6 is an elevation, partly in section and partly diagrammatic, of a pneumatic'relay mechanism suitable for controlling the refuse extractor of the system of Figural. I

In Figure l a Baum washer.box has a substanially U-shaped section casing 1 divided into t'wo parts 2, 3 21 depending weir 4. The part 2 of thefca'siiig is closcd at the top, while thep'art 3wh'h i n ludes'a pe rfo'r ed P at s? snea reat U lQ P'hQQ- P2. casing is caused tofiow up and downthrough the*grid5 emitted Apr. 23, 1957 by air pressure periodically admitted to and discharged from the closed part 2 of the casing in known manner, and'acting by way of a freely movable member in the form of a flexible diaphragm as shown at the lower part of the part 2 of the casing while a flow of water containing particles of coal 6 and refuse 7 is maintained over the grid 5. The pulsating flow of water causes a bed of refuse to collect on the grid 5 which is withdrawn in known manner by the refuse elevator 17.

A vertical tube 8 is connected to the space below the grid 5 and is led above the average water level in the washer box. The upper end of tube 8 is closed and connected via pipe 22 with a non-return inlet valve 9 to atmosphere and a non-return outlet valve 10 to a discharge conduit 11. These valves may be automatic or may be mechanically operable in phase with the pulsations in the washer box.

l, A leak-off valve or snift 12 is fitted in the discharge conduit 11 and may comprise a fine adjustment valve or fixed orifice, nozzle or tube (Figure 3). v

The discharge conduit 11 is connected to a manometer 23 and to a tube 24 extending upwardly within an inner cylindrical vessel 13 closed at its upper end and partly immersed in oil contained in an outer vessel 14. There is oil in the annular space between the two vessels and in the inner vessel 13 which contains air in the space between the surface of the oil within it and its closed upper end. Due to the pressure of this air the level of oil within vessel 13 is normally less than the oil level outside it. The vessel 13 is arranged for substantially vertical movement so that when the air pressure increases it tendsto rise and any ensuing movement is caused to operate the controller of the refuse extractor, for example, by the movement of a vertical operating rod 15 attached to the closed top of said vessel. The rod 15 is caused to control the rate of refuse removal in any convenient manner. As shown in Figure l the rod 15 is connected by a link 70 to the lever 71 of a valve 72 so that movement of the rod 15 controls a compressed air motor 73 which operates to move the gate 74 (indicated by broken lines) in the appropriate direction. The pressure at which vessel 13 commences to rise may be varied by adjusting its weight, and for this purpose removable weights 16 may be provided, for example arranged around the operating rod 15. The gate controls the rate at which refuse falls from the end of the grid 5 to be picked up by the elevator 17.

The system operates as follows:

When pressure is applied to part 2 of the washer casing an upsurge'of water takes place in part 3 and in the tube 8; this upsurge will be greater when the flow resistance through the refuse bed is high (i. e. when the refuse depth is great) than when the fiow resistance is low.

The column of water in tube 8 constitutes a water piston and performs pulsating strokes in time with the washer pulsations, the magnitude of the stroke depending on the thickness of the refuse bed 7. Each stroke of thewaterpiston downwards draws in air through valve 9 from the atmosphere and each stroke upwards discharge air through valve it! to the discharge conduit 11.

If the refuse bed 7 istoo deep, the flow resistance and the air pressure increase, vessel 13 and control rod 15 move upv/ards, and the refuse controller is actuated to remove refuse more rapidly. If the refuse bed is too shallow, the reverse operations occur. At the same time the manometer indicates the variations in air pressure.

Figure 2 shows asuitabl e arrangement for the valves 9, 10 which are of similar construction except that valve 9 is a one w a'y inlet valve while valve 10 is a one way outlet valve. "head 24 and stem 25 move within'a casiiig26bn' or off a"seatiiig;27 and'whenopen, air passes through entries 28,filter's 29, 'tube 30, apertures'31, an-

nular space 32 and tube 22, and thence flows partly into tube 8 and partly through tube 30A, apertures 31A, an-

nular space 32A, and tube 36 to the discharge conduit 11 and the leak 12. Figure 3 shows a convenient form of leak 12. The discharge conduit 11 terminates in a detachable casing 37 housing a rod 38 having a tapered recess 39 of the section shown in Figure 3A and slidable in a flanged bush 40. The rod 38 is rigid with and supported by a plate 43 having hook portions 41 slidable over fixed rods 42 which are secured to flange 45 on the end of conduit 11. Rotation of wheel 44 moves rod 38 up or down upon the release of locknuts 47, 48 and the position of rod 38 is indicated by a pointer 46 reading against a scale marked on the left hand rod 42. According to the'length' ofrod 38 extending within conduit 11, a.

greater or smaller air leak is provided.

If there were no leak-off from the discharge conduit 11, the action of the water piston in conjunction with the non-return valves 9, 10 would tend to produce a maximum pressure which would never fall. It is one of the functions of the leak 12 to obviate the possibility of this occurrence by providing a gradual escape for pumped air, so that the pressure in the discharge conduit 11 will fall when the water piston stroke decreases (that is to say when the refuse bed depth and flow resistance are reduced).

It is another function of the leak 12 to permit adjustment in the'range of control pressures produced in the discharge conduit 11 in order to match the requirements of the refuse extractor control employed in a particular application of the invention.

It is a still further function of the leak 12 to enable the working range of the indicating and controlling pressure to be kept low, therefore reducing the significance of accidental air leaks and emphasising the volumetric pumping effect of the water piston as compared with the pressure elfect.

The setting of rod 38 may be used to govern the relationship between the thickness of the refuse bed 7 retained on the grid and the operation of the refuse extractor. An increase in the opening 39 has the effect of increasing the depth of refuse 7 retained on the grid 5, and vice versa.

Figure 4 shows the arrangement of vessels 13 and 14 in greater detail. To minimise pulsating movements of the vessel 13 which tends to result from the intermittent discharge of air from the air pump, these movements may be damped by restricting the flow of oil between the inner and outer vessels 13, 14. This may be effected for example by closing the bottom of vessel 13 except for a narrow annular space 20. Further apertures for the passage of oil may be provided either in the closed bottom of the inner vessel or as shown at 21 in its side walls. in the latter case the apertures 21 are preferably arranged near the bottom of vessel 13 so as to provide for the escape of air if the internal air pressure exceeds that of the existing head of oil. The movement of control rod 15 is guided by guide 50.

Figure 5 shows an alternative method of adjusting the weight of vessel 1? In this case instead of using weights 16 the controller is operated through links 51, 52 pivoted at 53, and 54 pivoted to link 52, which is provided with a slidable weight 55, so as to vary the pressure required before the vessel 13 will rise.

The range of pressure and/or volume of air discharged by the air pump will vary according to the particular application of the invention.

Figure 6 illustrates diagrammatically one suitable form of connection between the control rod 15 and the refuse extractor-17. In some known types of washer box, refuse is extracted by means of a star wheel the rotation of which is controlled by a friction clutch or alternatively by the engagement or disengagement of a pawl carried on a mechanically oscillated member and arranged to drive the star wheel by means of a ratchet wheel. In a further known arrangement, a star wheel is driven by means of a ratchet wheel which is provided with a shield, the movement of which exposes a varying number of teeth for drive by a pawl oscillating with respect to the ratchet wheel. In this latter arrangement the movement of the shield may prevent the rotation of the star wheel or may-cause it to rotate at varying rates according to the number of teeth exposed.

The system of Figure 6 is a suitable form of pneumatic relay mechanism which may be used to control the rotation of a star wheel refuse extractor. The operating rod 15 is provided with a collar 57. When the vessel 13and rod 15 are in the position shown, collar 57 depresses the adjacent end of lever 58 which is pivoted at 59 and causes pad 60, which may be of rubber, to be held away from nozzle 61. A compressed air supply 62 is connected through a variable resistance 63, for ex- 4 ample a needle valve, to nozzle 61. The resistance 63 and nozzle 61 are also connected to a diaphragm motor 64. In the position shown, the compressed air leaks to atmosphere through nozzle 61 so that insufiicient pressure is available to operate the diaphragm motor 64. When the air pressure in vessel 13 causes float rod 15 and collar 57 to rise, pad closes on nozzle 61. The out of balance weight of lever 58 and pad 60 are adjusted so that when pad 60 rests on nozzle 61 the escape of air through the nozzle is prevented. The air pressure so supplied to the diaphragm motor 64 causes diaphragm 65 and pressure plate 66 carrying rod 67 to move in a downwards direction. Movement of rod 67 operates a friction clutch, pawl and ratchet gear, or like mechanism and thereby engages or disengages the drive of the star wheel refuse extractor.

The arrangement illustrated in Figure 6 may also be used to provide a means of varying the rate of refuse extraction in relationship with the thickness of the refuse bed in the washer box as, for example, by rotating a shield arranged to provide a variable speed drive by means of a pawl and ratchet wheel mechanism as described above. For this purpose vessel 13 is arranged to move with fairly little damping so that it has a pulsating up and down movement. The variable resistance 63 is adjusted so that the diaphragm motor is not operated when pad 60 is continuously free from nozzle 61, but is caused to operate to a greater or lesser extent when the nozzle is intermittently closed by the pulsating movement of rod 15, collar 57, lever 58 and pad 66. When so adjusted, the movement of diaphragm motor 64 and rod 67 is related to that proportion of the period of pulsation during which nozzle 61 is closed by pad 59. As rod 15 continues to rise, this proportion will increase until pad 60 rests on nozzle 61 during the whole of the period of pulsation of vessel 13, that is when collar 57 ceases to make any contact whatever with lever 58. By this means the movement of rod 67 may be varied in relationship to the air pressure in vessel 13. The motion of rod 67 may be used to control the rate of refuse extraction as for example by causing the movement of a shield 81 controlling the drive of a ratchet wheel 82 which drives a star wheel refuse extractor 83 and is itself driven by the engagement with its teeth of a pawl 84 carried on an oscillating member 85.

I claim:

1. A jig washer having a jigging liquid receiving container, a material supporting screen in said container, anair chamber connected to said container, mechanism for supplying air cyclically to said air chamber to force liquid in said container through said screen cyclically and simultaneously to cause pressure pulsations in said liquid, a fluid pump connected to said container and operable by the pressure pulsations of the liquid beneath said screen, a refuse extractor apparatus responsive to the rateof delivery of fluid from said pump to vary the rate of discharge of refuse from said jig washer by said refuse extractor.

2. A jig washer as claimed in claim 1 wherein the pump comprises a tube communicating at one end with the space below the supporting screen, a non-return entry valve for the admission of fluid connected to the other end of said tube, and a non-return discharge valve for the discharge of said fluid to a pump discharge conduit connected to said other end.

3. A jig washer as claimed in claim 2 wherein the pump is an air pump and the tube is connected through said non-return entry valve to atmosphere for the entry of atmospheric air.

4. A jig washer as claimed in claim 3 wherein the pump discharge conduit is connected to a leak.

5. A jig washer as claimed in claim 4 wherein the leak is of variable magnitude.

6. A jig washer as claimed in claim 4 and wherein the leak comprises a rod which can be connected to an adjustable length within the'pump discharge conduit, said rod having means defining a recess which is of segmental cross section and which tapers and is of decreasing depth in the direction remote from the adjacent end of the discharge conduit.

7. A jig washer as claimed in claim 4 wherein the pump is a freely movable member in a part of the washer casing remote from that in which the bed of refuse is formed.

8. A jig washer as claimed in claim 3 wherein the 6 pump discharge conduit is connected to a movable member, the movement of which is linked to and serves as a control for the operation of said refuse extractor.

9. A jig washer as claimed in claim 3 wherein the pump discharge conduit is connected to the free space within a vessel having a closed top and an open base and supported by a liquid in said vessel and in an annular space between said vessel and an outer vessel so that increase or decrease in pressure of fluid delivered to said space causes the said inner vessel to rise or fall respectively relatively to the said outer vessel, the said inner vessel carrying a control element linked to the refuse extractor.

10. A jig washer as claimed in claim 9 wherein the inner vessel is of adjustable weight.

11. A jig washer as claimed in claim 9 wherein said base has an opening and said pump discharge conduit passes through said opening in spaced relation to the edge thereof to leave a narrow annular opening around said conduit.

12. A jig washer as claimed in claim 9 wherein the wall of the inner vessel is perforated towards its base.

References Cited in the file of this patent

Images