US2019662A - Air control receiver - Google Patents

Description

Nw. 5, 1935. J.' D. s; DRINKWATER ET AL 2,0%562 AIR CONTROL RECEIVER Filed NOV. 2. 1952 l 2 Sheeis-Sheet 1 l A 3 /fnf/fenyen l M 5 m35 J. D. s. DRINKWATER ET AL, ,39662 AIR CONTROL RECEIVER Filed Nov. 2, 1932 2 Sheets-Sheet 2 j Ver? /a's' Patented Nov. 5, 1935 UNiTE STT PATENT OFFICE AIR CONTROL RECEIVER Application November 2, 1932, Serial No. 640,862

7 Claims.

Our invention relates to improvements in pneumatic drive mechanisms and processes of operating wash boxes or jigs oi' the Baums or air actuated type and is especialy applicable to a wash box or jig where water is circulated through a flowing sheet of material to be concentrated. or gravitally separated by means of the intermittent application of pneumatic pressure to a closed portion of the wash box whereby the water there- 10 in is by pneumatic pressure forced upwardly through the bed of material to be separated.

Experience shows that under some circumstances, it is desirable to modify orlvary the velocity of the Water as it passes upwardly through the bed of material during dii-ferent parts of the same stroke or impulse especially if we are separating materials whose specific gravities are not Widely diiferent. Experience has taught us that if we start each impulse suddenly and violently and decrease the force of the impulse to- Ward the end thereof, greatly improved separation takes place. We accomplish this by providing any suitable means for compressing air or gas and supplying it to the wash box, there being between the compressor and the wash box, a mechanically operated valve which opens and closes. When it opens, it admits air under pressure to the closed chamber thereby applying pressure to the water. When it is closed, it shuts off the air and permits the air already trapped in the chamber to escape. This opening and closing of the valve of course sets up a pulsating action in the water and it is this that provides the pulsating stream of water upwardly through the bed of material to be separated.

Normally the air control or quick opening valve when open, admits during the entire open period a continuous ilow of air at uniform pressure,

because the air is supplied to the header at a rate sufficient to cause the operation of the machine and sufficient to accomplish this. Thus the speed of ow of the water through the bed of material is under these circumstances substantially the same during the entire upward ow 45 period.

Experience shows that an important factor in the operation of the machine of the kind with which we are dealing is the rate of speed at which water is forced upwardly through the 50 bed of material to be classified or concentrated. It is obvious that the speed at which this water is forced through the bed depends upon the pressure of the air in the air pocket associated with the water. We propose to control the op- Cal 55 eration of the bed by controlling the pressure of the air in the pocket Where it produces its effect on the water. Preferably we find that it is desirable to start the upward movement of the water through the bed at a maximum and gradually decrease the velocity of the water. This 5 can be done by exerting a maximumpressure in the air pocket at the beginning of the upward movemem-,of the water and allowing or causing this' pressure to gradually decrease down to any desired minimum. 10

We have found in actual practice that Without any other change in the jig, the capacity-can be increased as much as thirty or thirty-live percent by controlling the rate of ow of the water upwardly through the bed as above indi- 15 cated and this increase `in capacity is accompanied by an improved effectiveness of separation.

This control of the air pressure and so control of the, bed may obviously be accomplished in many 20 different ways. Our preferred means takes the form of a separate air receiver associated with eachV cell ofthe wash box, togetherwith means for supplying air toV each cell and valves for controlling the volume of such air as it is supplied to and discharged from the receiver tothe air pocket. This control is accomplished by the use o f manually adjusted valves between the receiver and thelquick acting valve and between `the receiver and the air supply for controlling `to substantially the pressure of the uniform airv supply. When the quick acting valve is opened, the air under pressure in the receiver will rush out through the quick acting valve into the air pocket creating a maximum air pressure inthe air pocket and so exerting a maximum displacing effect on thewater. As the pressure in the receiver falls, the pressure applied to the water will also fall, the throttling of the air supply to the receiver making it impossible for the air supply to maintain the pressure in the receiver and so in the air pocket at a maximum. This pressure as it falls permits the rate of speed of water flowing through the bed to decrease down to a minimum which may be selected by the operator who adjusts the throttling valve between the air supply and the receiver to accomplish his desired adjustment.

The rate at which the Iair will be discharged from the receiver and the relation between the contribution made by the receiver and the uniform air supply to the air pocket is controlled by manipulation of the throttle valve between the receiver and the quick acting valve and the throttle valve between the receiver and the main air supply so th-at the operator can control the action of his bed within a Wide range of variations from an adjustment where the water rushes through the bed at maximum speed throughout the entire open period of the quick acting valve to an adjustment where the water velocity falls almost to zero toward the end of the open period of the quick acting valve.

Our invention is illustrated more or less diagrammatically in the accompanying drawings, wherein- Figure 1 is a top View;

Figure 2 is a front elevation;

Figure 3 is a section along the line 3-3 of Figure 2;

Figure 4 is a detail side elevation in part section showing the air control apparatus.

Like parts are indicate-d by like characters throughout the specification and drawings.

A is a wash or jig box having a curved bottom A1 and supported on a framework A2. It is divided into two longitudinal sections by a longitudinal partition A3 which extends down into the body of the box below the surface of the water maintained therein and divides the box longitudinally into air and working areas. The box is also divided up into a series of separate compartments A4 A4 and A5 A5 by transverse partition walls A6, A", which extend upwardly on the air side of the box as far as the heads A8 which close each of the air compartments and on the jigging side extend up to the screens A9 A1D which are set at diierent levels, the screen A9 which is at slightly higher levelthan the screen A10 being on the upstream end of the box. Raw material, for instance coal, is fed into the box through the sluice A11 and treated coal is discharged in a concentrated condition through the sluice A12.

B is a screw conveyor located in a trough at the bottom of the Wash or jig box A and is adapted to discharge refuse material, which passes through the screens and drops down into the body of the water, into the refuse elevator boots B1 B2 located at either end of the box. B3 B4 are refuse gates at the intake and discharge ends of the screen, adapted to be controlled by hand wheels B7 B8 at the front of the machine. Refuse gravitates to the bottom of the bed of iiowing coal upon the screen and particles too large to pass through the screen pass out between these gates and the screen through the chutes B5 Bfi and are discharged thereby into the refuse elevator boots. When coal is being treated, this refuse is dirt, clay, slate, shale, bone coal, and the like, which is heavier than the coal from which it is separated by gravity. t will be understood that the water level in the jig box is maintained high enough above the screens so that the entire bed of material as it travels along them is submerged.

Associated with each one of the air pockets is a quick acting valve C, comprising a reciprocating piston member driven by a stem C1, and connecting rod C2 from an eccentric C3 on the valve operating shaft C4. Air is supplied to each of these valves from a header C5 through a pipe C6 controlled by a manually adjusted valve C7, a receiver C8 and a manually adjusted valve C9, there being one quick acting valve and two manually adjusted valves and one receiver for each air pocket. The quick acting valve as it reciprocates, alternately causes compressed air to be supplied to the air pocket and to be discharged therefrom to the atmosphere. When air passes in through the valve C from the receiver C8 to the air pocket, 5

it force-s the water down on the air side of the longitudinal dividing walls A3 and this water rushes up through the screen and through the bed of material on the screen tending to raise and suspend the material and since the velocity w, of the water starting at a maximum gradually decreases, the heavier particles tend to descend under the influence of gravity more rapidly than the lighter particles. This progression is gradual in response to change in water velocity so that 15 stratication is thereby made more positive, more rapid and more effective. When the quick acting valve C permits ahr to escape from the pocket, the water tends to return by gravity in a reversed direction through the bed oi material and 20 the screen. At the same time the materials which remain in suspension at the end of the upward excursion of the water responsive to the opening of the quick acting valve settle back on the screen at a rate of speed more or less proportion- 25 ate to the speeiiic gravity of the individual particle. This cycle oi operation results in accurate, rapid and controlled stratiiication of the material leaving the heavy material nearest to the screen and the lighter materials progressively ar- 30 ranged above the heavier particles. Water may be supplied through the pipe C10 controlled by the manually adjusted valve Cll partially to reverse velocity of the water but primarily to provide -a sufficient carrying body of water to move 35 the stratied particles toward the exit end of the wash box in order that the lighter and heavier particles may be separated and separately discharged. The rate at which the valve shaft rotates controls the rate oi pulsation of the water 40 in the jig box and since as will hereinafter appear the air controlled by the quick acting valve comes to it at a generally constant pressure without pulsation, the only element controlling p'ulsation is the quick acting valve. 45

The valve C7 between the header and the receiver will normally be set such that the flow of air from the header to the receiver is less than the flow of air through the valve C and when the valve C is closed, air under pressure will flow 50 from the header into the receiver until the pressure in both is equalized. When the valve C 1s open the expansion of the air under pressure in the receiver will together with and supplemented by the flow of air from the header to the receiver 55 give a maximum air flow and air pressure at the beginning of the stroke. As the air in the receiver expands the volume of air available will decrease to a pointl ordinarily such that toward the end of the stroke the air will have expanded 60 to a maximum in the receiver and the only air flowing through the valve C will be the controlled air supply forced in from the main header or compressor. At that time the valve C will close and pressure will again be slowly built up in the 65 receiver. By this arrangement the stored air in the receiver assists the compressor in furnishing air to operate the jig and because the stored air effect decreases gradually during each stroke, the velocity of the water forced upwardly through 70 the separating bed will start 'at a maximum and go down to a minimum toward the end of the stroke. The result of this is that as the velocity of the water decreases, particles of lighter and closer specic gravities may be' given the oppor- 75 itunity to'settle out because experience showsthat Vpockets being boundedfby the surface ofthe water jthese will not settle in a rapidly moving upward Vcurrent of water. The violent'movement at the start is necessary to start the movement upward of the particles to be separated but decreasing the velocity of the Water toward the end of thepulsa- 'tion stroke gives the particles an opportunityto settle inthe still upward moving Water'at rates more or less in proportion to their specific gravity.

The'manual control valve C9 is inserted in the systemto make it possible to control the effect of the receiver and prevent too great run oil of the-air under pressure from the receiver if that is desired.

"D is av centrifugal blower driven by a motor D1 and discharging directly into the header C5. This blower'furnishes air under pressure to the header at approximately constant pressure independent of volume displaced up to the maximum capacity ofthe blower and since the blower installed in the device is of course of big enough capacity to carry/the maximum load which may be imposed upon it, it is a fact that in the main, pressure variations are reduced to a minimum so far as the blower itself is concerned. The blower D draws 'in air through the'intake pipe D10.

This pipe is controlled by a blast gate D2, preferably of the butterfly type. This gate is controlled by an operating rod D3 extending across the machine to the front where it is provided with a handle or yis needed as would be the case if a blower giving pulsating air current were used and so the quick acting valves are the only elements in the system controlling the rate of pulsation and since they `release successive impulses of air at substantially constant pressure the rate of pulsation and its magnitude may be accurately controlled.

The hand control valves between the header and each air pocket will be adjusted by the operator when the machine rst starts to control the flow of air from the header to the quick acting valve because experience shows that usually different quantities of air should be fed to the different air pockets.

The blast gate in the intake to the compressor has a two-fold function. It is used to altogether stop the supply of compressed air to the system when the operator desires so to do and it is used to control the pressure of air fed to the system while in operation.

It will be understood that in a sense the storage of air under full pressure in the receiver whereby the stored air in part at least accomplishes the pulsating eiect is similar to the cut off in a steam engine, that is to say,the air is stored at maximum pressure in the receiver so that as work takes place the pressure gradually falls off, thereby controlling the operation. A more or less expansion effect is provided by the receiver because the supply of air to it is restricted to greater or lesser extent.

We claim:

1. In combination in a Wash box, a generally longitudinal partition therein and a generally transverse partition, said latter partition dividing the box into a plurality of cells, a screen lying on one side of the longitudinal partition and a plurality of closed air pockets formed on the other side of the partitio=n,the under side of said air on the side of thelongitudinal partition-opposite the'screem means lfor supplying water to :said

Wash'box and for maintaining the level ofvsaid water above saidscreen, means for maintaining a 5 continuously iiowing bed of Vfragmentary material on the screen and beneath the Water level, an air compressor, a general header connected to said compressor and adapted to supply air to each of said cells, there being lpipes connecting said .l0 header with each of said cells, a quick acting valve associated vwith each of said pipes and adapted alternately to permit the iniiow of compressedair lfrom the header toeach cell, and individualfreceivers, one for each cell, interposed between said 15 general header and one of said quick actingv valves.

2. In combination in a wash box, a generally longitudinal partition therein and a generally transverse partition, said latter partition dividing the box into a plurality of cells, a screen lying on 20 one side of the longitudinal partition and a plurality of closed air pockets formed on the other side of the partition, the under side of said air pockets being bounded by the surface of the water on the side of the longitudinal partition opposite the screen, means for supplying water to said wash box and for maintaining the level of said water above said screen, means for maintaining a continuously flowing bed of fragmentary material on the screen and beneath the Water level, an aircompressor, a general header connected tosaid compressor. and adapted to supply air to each of said cells, there being pipes connecting said header with each of .said cells, a quick acting valve associated with each of said'pipes and adapted35 alternately to permit the inilow of compressed air from the header to each cell, and individual receivers, one for each cell, interposed between said general header and one of said quick acting valves, the rate of air iiow from the generalAO header to each individual receiver during any selected time interval being less than the rate of iiow through the quick acting valve from the individual receiver to the pocket during an equivalent time interval.

3. In combination in a wash box, a generally longitudinal partition therein and a generally transverse partition, said latter partition dividing the box into a plurality of cells, a screen lying on one side of the longitudinal partition and a plurality of closed air pockets formed on the other side of the partition, the under side of said air pockets being bounded by the surface of the Water on the side of the longitudinal partition opposite the screen, means for supplying water to said wash box and for maintaining the level of said water above said screen, means for maintaining a continuously flowing bed of fragmentary material on the screen and beneath the water level, an air compressor, a general header connected to said compressor and adapted to supply air to each of said cells, there being pipes connecting said header with each of said cells, a quick acting valve associated with each of said pipes and adapted alternately to permit the iniiow of compressed air from the header to each cell, and individual receivers, one for each cell, interposed between said general header and one of said quick acting valves, and manually controlled valves interposed, one between said general header and each of said individual receivers, whereby throttling may be carried out between said general header and each of said receivers.

'4. In combination in a wash box, a generally longitudinal partition therein and a generally transverse partition, said latter partition dividing the box into a plurality of cells, a screen lying on one side of the longitudinal partition and a plurality of closed air pockets formed on the other side of the partition, the under side of said air pockets being bounded by the surface of the water on the side of the longitudinal partition opposite the screen, means for supplying water to said wash box and for maintaining the level of said Water above said screen, means for maintaining a continuously flowing bed of fragmentary material on the screen and beneath the water level, an air compressor, a general header connected to said compressor and adapted to supply air to each of said cells, there being pipes connecting said header with each of said cells, a quick acting Valve associated with each of said pipes andv adapted alternately to permit the infiow of compressed air from the header to each cell, and individual receivers, one for each cell, interposed between said general header and one of said quick acting valves, and a manually controlled valve between each of said individual receivers and the cell with which it is connected.

5. In combination in a Wash box, a generally longitudinal partition therein and a generally transverse partition, said latter partition divid ing the box into a plurality of cells, a screen lying on one side of the longitudinal partition and a plurality of closed air pockets formed on the other side of the partition, the under side of said air pockets being bounded by the surface of the water on the side of the longitudinal partition opposite the screen, means for supplying water to 'said Wash box and for maintaining the level of said water above said screen, means for maintaining a continuously flowingl bed of fragmentary material on the screen and beneath the water level, an air compressor, a general header connected to said compressor and adapted to supply air to each of said cells, there being pipes connecting said header with each of said cells, a quick acting valve associated with each of said pipes and adapted alternately to permit the inflow of compressed air from the header to each cell, and individual receivers, one for each cell, interposed between said general header and one of said quick acting valves, and manually controlled Valves, one on each side of each of said individual receivers.

6. A wash boX comprising a tank containing 5 the water level, an air receiver of less capacity than that needed fer each stroke connected to the air pocket and supplying air thereto, means in constant communication with the receiver for continuously supplying air to the receiver at a rate less than the rate of ow from the receiver into the air pocket, and a quick acting valve in the connection between the receiver and air pocket adapted to alternately permit the flow ofV air from the receiver into the pocket and outow of air from the pocket to atmosphere, whereby operation of the quick acting valve causes movement of the water initially at high velocity and then at gradually decreasing Velocity after the airl in the receiver has been exhausted.

'1. The method of gravita-lly separating a mass of fragmentary material which consists in supporting the mass in a body of fluid, continuously supplying air at a uniform rate to a storage com pression zone, discharging air from said zone into contact with the body of uid at a greater rate than the air is supplied to said zone to cause the uid to pass through the mass of fragmentary material at high Velocity, separating the lighter particles from the mass, and continuing the supply of air to the storage zone and through the zone into contact with the body of fluid after discharge of the stored air from the storage zone, whereby the body of iiuid is moved initially at high velocity and subsequently at gradually decreasing velocity.

JAMES D. S. DRINKWATER. JOHN H. D. PETERSEN.

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