US2055161A - Coal washing machine - Google Patents

Description

2 Sheets-Sheet' l G. A. vl'ssA:

COAL WASHING MACHINE Filed March 21, 1934 j sept. 2z, 1936.

/Mf/vrofv U5 774 YE VIS-SHC @Y #ffy l Sept. 22, 1936. G. A. vlssAc COAL WASHING MACHINE Filed March 2l, 1954 2 SheetsfSheet 2- 16 j/vvE/v G Us Tn TOI? Patented sept. 22, 1936 Alberta, Canada ApplicationMarch 21, 1934, Serial N0. 716,707 In CanadaApril 2'1, 1933 This invention relates to improvements in coal washers of the type in which the particles of coal are :separated from the particles of `rock "by means 4of an upwardlyiiow-ing column of water 5. into which boththecoal and the rock are introduced and from which they are separately withdrawn, and the `,objects of the .invention are to effect a more economical and accurate separation, toprevent back currents in the column of water,

and to create therein the proper still condition which will enable separation to be readily -eiected by differences in -specic gravity. Further objects of the A invention are generally tosimplify and improve acoal washer and the vmethod of op- 155 erating the same to `-effect the best separation without costly sizing and with a minimum-consumption `of power. Carrying out the.invention,instead of usinga single current of water to A effect the separation I 29 employ .a `combined current :formed from streams of diierent velocities, one of which is pulsating, and employ these streams in apparatus having various improved mechanical .arrangements Vas will be hereinafter more fully set forth and described in the accompanying -specifications land drawings.

-v In the drawings Fig. l is a longitudinal section of a coal washer embodying the invention. l

Figv2isaplanview.` I f 39 Figui?, isa sectionron the line 3-3 of Fig. l. j

' Fig. 4 is an assembly plan showing vseveral units assembled foruse on small -coal sizes. Inthe drawings like gures of reference indicate -correspondingwparts in all the gures.

Referring to the drawings, Iindicates the main water supplyfvalve controlling the inflow of water through the main inlet pipe 2 which opens into the-,main water supply chamber 3, the latter 'con- Aveniently having air petcocks 4in the wall thereof :in which may be manually `operated to regulate the level of Yliquid in the chamber `3. 5 `indicates a butterfly valve driven at variables-peed by suitable means and designed -to produce a pulsating current of water as .hereinafter described.

.45 6 is .an auxiliary supply valve leading from the chamber@ by which a continuous current of water of regulated amount is supplied.

'I indicates a current deflector pivotally mounted and designed to be adjustably held in any po- 159 sition by which the upward current may be de- `flectedfacting in combination with the delector plate t at the bottom of the main surge chamber 8. At the bottomV ofthe surge chamber 8 is connected an auxiliarywater supply Ill controlled by 155 :an auxiliarywater supply valve Il and having a 4 Claims. (Cl. 209-457) sludge valve 'I2 through which the sludge may from time to time be withdrawn.

`On theu upper part of the surge Vchamber 8 an inclined perforated plate I3 is provided leading to the'rock-discharge I4. The clean coal is adapt- 5 ed -to be discharged at the upper end and through the ,discharge port I5 and over the clean coal grate I6 which is adjustable in position so that its upper level may be changed. Adjacent to this coal grate but below the same is a rock gate 150 II immediately nabove the opening I4. The rock passing through the discharge I4 is designed to fall into a rock scraper conveyor I8 of any convenient design, shown schematically in Fig. 4, by which it .-isconveyed away. The clean coal passes l5 out through a clean coal discharge I9. j

The raw coal is designed to be supplied from a bin .-20 to one -or more feed gates 2-I thepassage being assisted by flushing water controlled by the flushing vfeed water valve 22. 20

The `waterwithin the surge vchamber 8 `is further controlledby an outlet leading from above the conveyor I8 andA controlled by a depression butterfly valve 23; Theamount of the opening of this valve is designed to be -automatically con- 25 trolled by means of a lever 23a connected by links 24a, 24D, and a pivoted rocker arm 24e to a weight 24 `suspended within the chamber 8 and operating as hereinafter described.

v Having now described the various parts of the 30 apparatus I will brieiiy refer to the method of operating the same. 1

. The raw -coal is delivered into the bin 20 and isA discharged and controlled by a series of gates 2| and thence ushed along a suitable troughinto 35 the top of the surge chamber 8 by means of water controlled bythe flushing `valve 22. By properly regulating this current of water an initial separation` of the coal (shown in black) from the rock (shown in white) is eiected, the lighter pieces of coal being projected further up in the washing box or surge chamber 8 than the pieces of rock.

It is desirable that for greater eiiiciency the bottom of the trough should be as close as possible to the level ofthe water in the chamber 8.

While the device is in operation a continuous upward current of `water is maintained in the surge chamber 8 whose speed is adjusted by means of the valves I and 6. The minimum speed of this stream (VI) should be just below 5o the limit speed of free fall of the lightest, pieces of coal in water; in other words, when the water current'in the surge chamber Vattains that speed (VI) the coal pieces `are practically stillpor just start to fall and, naturally, the rock pieces sink.

' be theoretically that which will maintain the rock still and move the coal upward. VIn -this way the raw coal in the surge chamber 8 is submitted to v a series of speeds varying between VI and V2 causing the coal to remain stillor tov move upward and the rock to sink downor to remain still. In other words the coal is gradually jumping up and the rock is gradually sinking down. YThe coal isvvnally evacuatedwith the water by the overflow at I whose level is adjusted by gate I6 Vand.-

the rock falls onto the perforated plate I3 which has a Vslope just sufficient tov allow the rock to slide down gently to the scraper conveyor I8 which moves it out gradually. The sliding gate I1 and the depression water valve 23 allows the necessary adjustment to be made to maintain a protective bed of rock on the perforated plate. The depression butterfly Valve 23 also enables a very accurate control to be maintained of the water conditions in the surge chamber 8. The cylinder 2B is selected of proper weight and is designed to rest on the rock bed so that as the rock bed increasesthe weight will be raised which will adjust the butterfly valve through the chain and pulley connections Vshown and thereby effect-a regulation lin the outflow from thechamber 8.

" Alll the water required for the operation is supplied from the pipes 2 and 22, and which should l be connected to a centrifugal pump. All of the upward current of water is fedA by the pipe 2 and distributed equallyover the surface ofthe plate I3 from the tank 3. The opening of the valve 6 supplying the main current and the valve 5 sup-` plying the pulsating current are conveniently ex# tended acrossjthe whole width of the washing tank.V

It will be seen that the rotatingvalve 5 is open on only part of its revolution. When the valve l5 is Aclosed the continuous water pressure (brought in by pipe 2 from the continuous current "of the feeding centrifugal pump) is" used to compress the air on top of the tank 3; when valve 5 opens this air pressure is used to bringup'the speed ofthe upward'current in the surge chamber in they proper manner and to the proper amount; During the operation the air in the tank 3is compressed by the water pressure onlyand mostly is farating of the-rock from the coal.

not allowed to escape. There is always a continuous upward current of water through the washing bed whichV positively ensures against back streams and back currents andenaloles the device to Acreate vvery still water"conditions for the sepl These .sun conditions, realized for light pieces at minimum currentrand for heavier pieces at maximum current,"en'able the separation to be effected by differences of acceleration'and consequently by differences inV specic gravity only independently of their size. The prevention of back currents is desirable as their yexistence would mean a de- 'struction of the separation accomplished in the upward current since they produce conditions in 'which light pieces would sink faster than heavy ones.' It isfpossible by the device t0 effect an eiiicient separation without previously sizing the particles of coal. The consumption of water is very low and substantially less than in a continuous upward current machine. The moving parts are few including only the valve 5 and the rotary conveyor. The device may therefore be operated with minimum consumption of power.

The butterfly valve 5 which controls the passageof water from the chamber 3 to the chamber 8 extends across the full Width of the chamber so that, when it is open, a rapid surge of water` from the chamber 3 into the chamber 8 takes-place, producing an upward current in the chamber 8 which however is decelerated as the headgof water in the chamber 3 is reduced and/or `the air pressure released. When this butterfly valve or gate 5 is in closed position, which is only during less than half of its rotation, water and air pressure is accumulated in the chamber 3.

When the gate 5 opens this accumulated pressure at its maxima, is relieved through the whole width of the machine sharply and quickly. Thereafter the pressure in the tank compartment 3 decreases and upsurge takes the form of a uniformly retarded motion; consequently, the particles are retarded according to their specific gravity alone, particles of lightest specific gravity go upwardly with the greatest acceleration. At the end of this upsurge'practically still conditions prevail in the chamber 8, particles are falling with an acceleration according to specific gravity alone. The downstroke then develops. During this downstrokewhile the valve 5 is closed the water flows through the valve 6 in a continuous current, which current however is accelerated through the building up of hydrostatic and pneumatic pressure in the chamber 3 so that the continuous current of water flowing upwardly is gradually accelerated, with the result that the relative motion ofthe particles is an accelerated downward motion.

'Ihe description as shown in Figures 1 to 3 illustrates they general application of the invention. When it is desired to operate on very small sizes of coal containing a large amount of middling's an arrangement such as shown in Fig. 4 may be provided in which a plurality of units similar to those shown in Figures 1 to 3 are assembled side byside. The water current in this case is parallel` to thel partition between the Vair and washing tank. "AI'wo washing tanks are provided each one having two air tanks. The first washing tank may eliminate a heavy refuse by a screw conveyor rather-than by a scraper conveyor, while the Vsecond tankreliminates a middling product. The automatic'regulation effected by means of the weight'24 may, if desired, be modied by placing the cylinder 24 in the rock chamber 25 above the conveyer, the cylinder in this case being a float, and operates by reason of the fact that an increased bed of rock will giveV an increased 'pressure inv this chamber. It will be understood that the butterfly valve can be replaced by any equilibrated valve. It will be obvious that the water supplied by the pipes 2 and 22 can -besupplied from a pump or tank or any water system having the necessary 'head or pressure.

: Although the invention has been described herein with reference to the use of water as the separating medium, it will be understood that any other fluid might be used if available, and

the-term water inthe following claims is ininvention without departing from the spirit thereof or the scope of the claims and, therefore, the exact forms shown are to be taken as illustrative only and not in a limiting sense, and I desire that only such limitations shall be placed thereon as are imposed by .the prio.:` art or are specifically set forth in the appended claims.

What I claim as my invention is:

1. The method of separating mixed materials of different specic gravities, which consists in passing such materials to a counter-flow of a continuous current of water, gradually accelerating the current from a minimum to a maximum velocity, suddenly increasing the volume of the current as it reaches maximum velocity and then gradually decelerating it to initial minimum velocity, decreasing the volume of the current to its initial volume, and successively repeating the cycle while passing material to the current.

2. The method of separating mixed materials of different specific gravities, which consists in passing such material downwardly into a continuously up flowing current of water, gradually accelerating the velocity of the current to a peak sufficient to suspend the fall of the heavier material, then suddenly increasing the volume of the current to cause a surge lifting the lighter material above the heavier and at the same time decelerating the current velocity to permit free fall of the heavier material, decreasing the current to its initial volume, and successively repeating the cycle While passing material into the current.

3. In a system for washing coal or the like, the method of effecting separation of the lighter material from the heavier which consists in feeding a batch of material into a counter current of water ilowing at a velocity suiiicient to retard all of the lighter material and to permit fall of the heavier material, gradually accelerating the current velocity to a point suflicient to suspend fall of the heavier material, then suddenly increasing the volume of the current to cause a surge lifting the lighter material away from the heavier and immediately thereafter decelerating the current velocity to a point sufficient to permit free fall of the heavier material and decreasing the current to its initial volume.

4. In a jig, a surge chamber having an inclined screen therein, a pressure chamber adjoining said surge chamber, means for supplying water to said pressure chamber against pressure therein, a passageway connecting said chambers below said screen, valve means in said passageway for periodically allowing feed of water under pressure from said pressure chamber in surges to the surge chamber, and valve means also in said passageway adjacent said rst-named valve means, said second valve means being adjustable and continuously open to establish a constant iiow of water from said pressure chamber Vupwardly through the screen in said surge chamber.

GUSTAVE ANDRE VISSAC.

Images