US2245942A - Apparatus for separating material - Google Patents

Description

June 17, 1941. E. STUMP 2,245,942

APPARATUS FOR SEPARATING MATERIAL Original Filed June 29, 1934 s Sheets-Sheet 1 June 17, 1941. E, STUMP APPARATUS FOR SEPARATING MATERIAL s Sheets-Sheet 2 Original Filed June 29, 1934 June 17, 1941. E. STUMP 2,245,942

APPARATUS FOR SEPARATING MATERIAL Original Filed June 29, 1934 6 Sheets-Sheet 3 In V67? for q/Zffariz eys.

June 17, 1941. E. STUMP APPARATUS FOR SEPARATING MATERIAL 6 Sheets-Sheet 5 Original Filed June 29, 1934 E. STUMP APPARATUS FOR SEPARATING MATERIAL June 17, 1941.

Original Filed June 29, 1934 6 Sheets-Sheet 6 La .5 -1-1:-1: w w w 1 uafiaaiiiia Patented June 17, 1941 APPARATUS FOR SEPARATING MATERIAL Earl Stump,

Schaei'er of Illinois Harvey, Ill., assignor to Roberts and Company, Chicago, 11]., a corporation Application June 29, 1934, Serial No. 733,053 Renewed October 20, 1938 27 Claims.

My invention relates to apparatus for gravitally separating particles of difi'erent specific gravities and while especially applicable to and useful in connection with the cleaning of coal by air, it may be used equally well for separating other material both by the use of air, gas, or other fluid separating or floating media.

One object of my invention is to provide a machine which can be applied to the separation of fragmentary material in one operation through a comparatively wide range of sizes, thereby dispensing with excessive preliminary screening.

Another object of my invention is to provide an air separating device wherein with slight changes, the device may be used for many different size ranges so that the problem of maintaining a stock of machines is minimized.

Another object is to provide an air separating apparatus wherein the major part of the apparatus is the same for all sizes and conditions and only a relatively small part of the apparatus needs to be changed to take care of varying operating conditions.

Another object is to provide a material separating device which will be simple, light, inexpensive and large capacity, take up a minimum amount of room, have a minimum of vibration and require a minimum of power.

Other objects will appear from time to time throughout the specification and claims.

My invention is illustrated more or less diagrammatically in the accompanying drawings, wherein Figure 1 is a side-elevation of the device;

Figure 2 is a longitudinal section on an enlarged scale through the device shown in Figure 1;

Figure 3 is a section along the line 3-3 of Figure 1;

Figure 4 is an enlarged section along the line 4-4 of Figure 2;

Figure 5 is an enlarged section along the line 55 of Figure-4;

Figure 6 is a section somewhat similar to Figure 2 and intended especially for the purpose of showing the way in which the interchangeable resistance bed and air chamber is assembled with the machine;

Figure 7 is a detail longitudinal section along a line similar to the section in Figure 2 showing a modified form of the device;

Figure 8 is a section along the line 8-8 of Figure 7;

Figure 9 is a section along a line similar to the section in Figure 7 but showing a further modified form;

Figure 10 is a section along the line Ill-l0 of Figure 1;

Figure 11 is a section through a modified form of resistance bed'and air box.

Like parts are indicated by like characters throughout the specification and drawings.

It will be understood in general that my apparatus comprises a hopper or chute through which coal or other material to be classified is fed, a gate associated with a reciprocating feeder for controlling the flow of the raw material to the machine, a source of air, gas or fluid under pressure and means for controlling the rate at which the fluid is supplied, a valve which independent of the general rate of flow causes the fluid to move with a pulsating stream, an air chamber adapted to receive this fluid and a pervious resistance bed bounding the upper side of the air chamber so that a pulsating current of air, gas, or liquid is discharged upwardly through this resistance bed, the feeder meanwhile supplying a stream of fragmentary or comminuted material which is caused to flow downwardly across the top of the resistance bed. The pulsating air current floats the material, exerting a more pronounced effect on the light material than on the heavy so as to cause generally horizontal stratification, the stream of material being more orless homogeneous at its upper end and gradually becoming stratified at itslower end so that at the lower end a horizontal separation may be made into preferably three classes, heavy at the bottom, middlings at the center and light at the top. The floating and separating efiect of the air current is assisted by means of stirring or supporting means immersed in the air stream, which tends .to assist the air stratification in part at least by supporting the weight of the current or stream of material.

The control is generally pneumatic responsive to variation in the pressure in the air box and preferably affects the rate at which the heavy material and the middlings are discharged from the apparatus. The pneumatic apparatus is manually adjusted to provide the desired operation.

The apparatus described and shown is applicable for treating any type of material and for any size range, changes to take care of variations being made 'by changing the air box and the resistance bed and by changing the angle of inclination of the resistance bed along which the material flows and by the other adjustments as shown.

The reference numerals I and 2 indicate horizontal main supporting channel frame members. Projecting upwardly from them are vertical columns 3, 4, ii. These columns support an end plate 6, and side plates I and 8. Above these, are transparent side plates 9, l0, these plates being bounded along their upper edges by beams ll, i2, which beams carry a closed air and dust receiving hood i3. The columns 5 have associated with them an end plate 44 and side plates IE to form a control and chute containing structure which may be separately removed from the apparatus without interfering with the panels I, 8, 9, i0. Projecting upwardly from the members l, 2 are columns "5, which together with the columns 3 carry a platform H, which platform supports an eccentric shaft is driving by means of a link l9 9. cross member which in turn drives a reciprocating feeder plate 2! adapted to travel on rollers 22. This feeder plate forms the bottom of a feed box 23 having an adjustable gate 24 adapted to receive material to be treated from the bottom of a hopper 25.

The numeral 26 indicates a blower mounted on the beams i adapted to discharge air or gas under pressure through the pipe 21, the discharge of air being controlled by the butterfly valve 28 having an adjusting handle 29 and a lock screw 30 traveling along a quadrant 3i. The pipe 21 communicates with the pipe 32 mounted on the columns I8 and 33. The numeral 34 indicates a butterfly valve contained within the pipe section 32 driven by a. belt 35 on a pulley 36 from any suitable source of power not here shown. A sprocket 31 associated with the belt pulley drives a chain 38 which by means of a sprocket 39 drives the eccentric shaft IS. The rotation of the butterfly valve alternately opens and closes the pipe 32 so as to provide for a pulsating flow of air or gas from the blower to the apparatus.

The numeral 40 indicates an air box. It has downwardly extending flanges 4| adapted to travel on rollers 42 supported on the side frames 1. This air box is closed at bottom, sides and front. At the rear end it terminates in a sleeve 43 communicating by means of a flexible conduit 44 with the pipe 32 so that the pulsating stream of air is fed to the interior of the air box.

The air box is bounded on its upper side by a marble pack 45. This marble pack is contained between an upper perforate piate 46 rigidly ,mounted on the air box and a lower adjustable plate 41 which may be moved toward and from the upper plate by means of a series of adjusting screws 4!. These screws may be manipulated to control the density of the pack, to control the angle of the plates 46 and 41 as the case may be and to exert a suflicient pressure on the marbles which marbles may be ceramic or metallic or even of other material as the case may be. It will be understood that this marble pack exerts a fixed but controllable resistance to the escape of air through the air box through the perforate wall 46. All the air fed to the air box by the blower through the fixed butterfly valve and through the pulsator is compelled to escape through the marble pack upwardly through the treatment zone.

In the device shown in Figures 1, 2, the slope of the air box and the marble pack is controlled by means of the adjusting screw 49 pivoted at one end on a bracket 50 associated with the rearmost end of the air box, extending up through a bracket 5i on the end wall 5 and associated with an adjusting nut 52 whereby the air box may be raised and lowered rotating about the pivot pin 53, its lower position being limited by its engagement with the rollers 42.

In the modified form shown in Figure 6. the means for adjusting the air box is somewhat different. There we have a winch 54 on a bracket 55 on the column IS. A cable 56 is wound about that winch and engages a clevice 51 on the bracket 50. As shown in Figure 6 in full lines, the air box is being drawn into position by means of the winch, the pivot pin 53 having not yet engaged the slot 58 in which it will seat when the air box is in position. When the air box has been drawn to the position shown in dotted lines, 53 will seat in 58, then the cable will be released and brought up over the pulley 59. After that the angular adjustment of the air box can be made by exerting a tension on the cable through the Windlass, the air box for instance being raised to the position shown in dot and dash lines in Figure 6. In either case, the air box may be additionally locked in position by means of the hand screws 60 traveling in slots Si in the plates I which screws also tend to clamp the plates against the air box and prevent leakage of air outwardly and downwardly along the walls of the air box from the working chamber above the box.

The working chamber wherein the separating is done is of course the chamber between the glass or transparent panels 8, ID, the perforate plate 46 and the hood iii. The feeder 2| discharges the material to be treated into that chamber, the material falling upon the perforate plate 46 until a bed of flowing material such as is shown in Figure 2 has been formed.

The bed of material is relatively deep. The material as it feeds in is as shown in Figure 2 generally homogeneous. The pulsating effect of the air tends to float the material downwardly along its inclined path, much as it would be floated in a stream of water. The vibration of the bed itself, there being no vibration of the machine, tends to assist a gradual stratification as is indicated more or less in the drawing. the heavier materials tending to seek the bottom of the bed, the lighter particles tending to seek the top and there being an intermediate or middling zone. In order to means are provided.

The stirring means may take a number of different forms. For instance, in Figures 2 and 3, we have two longitudinal bars 62 having a plurality of cross bars 63 forming a kind of a grid iron, there being lugs 64 projecting from this grid iron, the lugs being suspended from hanger bars 65 on the cross bars 58. A link 61 extending forwardly from one of the lugs 64 to a rock arm 64 reciprocates the grid iron. The rock arm 68, having a series of adjusting holes 59 at one end to any one of which the link 6| may be pivoted, is driven at its other end by means of a connecting rod 10, which is associated with the reciprocating feeder 2| so that the movement of the grid iron is in consonance with the reciprocation of the feeder and so also with the movement of the pulsator valve. The movement of the grid iron may, however, be independent of the feeder and valve.

In the modified form shown in Figure 7, instead of using a grid iron, a plurality of parallel perforate plates ll, 12 are used, the plates II, I2 being spaced and held together by means of assist in this action, stirringadjusting bolts 13 and suspended from hanger rods 14. In this case a connecting rod 15 extends between the reciprocating feeder 2| and a lug 168 on the upper one of the plates 1I. It will be noted from Figures 7 and 8, that in this case the slots in the plates are longer in a longitudinal direction than their width and these plates similar to the grid iron are so disposed that at least the lowermost one is rather close to the perforate material supporting surface which bounds the upper side of the marble pack.

The operation of these'plates or ofthe grid iron is two-fold. It tends to gulde the flow of material along lines parallel with the supportingv surface on the upper wall of the marblepack and to support part of the weight of the material so as to prevent an undue increase in density of theflowing material from top to bottom. Also it tends to stir the material and assist by imparting longitudinal vibration to the flowing particles in the stratification eflect imparted by the transverse vibration from the air stream. An additional important effect of the grid or plate is that by its movement, it-tends to'break down and interrupt incipient blowing through the bed by closing up air pipes or pockets which may be formed in the material. The movement of the zoning plate is slow and perhaps should be described as longitudinal displacement rather than longitudinal vibration and its stirring and supporting function in connection with stratification loosen the bed to permit stratification and in connection with the preventing of air blasts through the bed is of the utmost importance.

In the modified form shown in Figure 9, the plates 16, 11 are mounted on the rods 18 but are held quiescent in the bed of material having no stirring efiect though the stratifying, guiding and load supporting effect is the same.

Projecting downwardly from the floor of the air box 48 is a sleeve 19. A flexible conduit 88 joins the sleeve with a pipe 8| mounted in the main supporting frame. This pipe is adapted to be controlled by means of a butterfly valve 82 with controlling handle 83. The pipe extends outwardly through the frame and has an upward extension 84 surrounded by a water box 85. This water box 85 is closed by a cover 86. It contains water 81, and has immersed therein a float cylinder 88 open at the bottom and enclosing the tank 84, there being an air chamber 89 formed between the water and the floating member 88. Projecting upwardly from the float cylinder 88 is a control rod 88 passing out through the cover 86 by way of a packing gland 9I. This rod 98 terminates in a yoke 92 pivoted on the operating lever 93, which lever in turn is pivoted on a hanger 94 on the main frame. It will be understood that the,pressure of air in the air box 48 is exerted through the pipe 84 upon the underside of the float 88, tending to raise it and to rotate the lever 93 in a counter clockwise direction as shown in Figure 1. This movement is resisted by the spring 95 which is contained within the adjusting cylinder 96. This spring is compressed between a pin 91 anchored on the bracket 98 on the box 85 and between the cap or cover 99, of the cylinder 96. The other end of the cylinder is covered by a cap I88 associated with a turn buckle I8I pivoted in one of the holes I82 on the lever 93. The tension of the spring may be adjusted by manipulating the turn buckle. Fine adjustment is obtained by means of the weight I83 adapted 3 to slide along the yoke I84 on the lever 93 and provided with a set screw I85 to lock the weight in place.

Referring now to Figure 2, it will be noted that immediately beneath and at the end of the deck or platform which forms the upper boundary of the marble pack is a fixed chute I86, which terminates at a pivoted gate I81. The gate comes up against a stop plate I88 and this gate is mounted for rotation with the shaft I89. The shaft I89 comes out through the wall I5 and carries a lever II8. This lever is provided at one end with an adjustable counterweight III, at the other end it has a series of holes in one of which is pivoted a yoke 2 connected by means of a turn buckle II3 with one of the adjusting holes H4 on the lever 93 so that upward movement of the float 88 in response to increased pressure in the air box will tend to open the gate I88 and allow an increased discharge of heavy material down through the chute H5.

Overlying the chute I86 is a middlings chute II6, pivoted at II1 on the plate or wall I5 and adapted to be raised or lowered by manipulation of the handle II8 associated with the quadrant H9 and the locking screw I28 so as to raise and lower the receiving edge of the middling chute and control the maximum depth of the refuse bed. This chute II6 discharges over a fixed chute I2I, which terminates in turn at the gate I22 which gate is mounted on the pivot shaft I23, which carries a lever I24 with its adjustabl counterweight I 25 and is connected at the other end by means of the turn buckle and linkage I26 with the lever 93. The adjustability of the pivot points of the connections between the levers H8 and I24 and the lever 93 gives a wide range of response of gate opening to the variation in pressure of air in the air box. The numeral I 21 indicates a coal chute pivoted at I21a and provided with an adjusting quadrant I28 whereby it may be raised and lowered and locked in position by means of the adjusting screw I29 so as to control the depth of the middlings zone.

It will be noted that in the devices of Figures 2 and 7, the adjustment of the coal chute and the middling chute is independent of the position of the plates H and 12 or the grid iron 63. In the device of Figure 9, however, the plates 16 and 11 are attached to the chutes, 16 being attached to a slightly different form of coal chute I 38, and the plate 11 to a slightly different form of middling chute I3I so that in this case the adjustments of the height of the plate and of the chutes themselves must be made synchronously.

It will be noted that while the refuse chute and the middling chute are shown in the drawings as not being full of material. nevertheless they will normally be filled and the control of the flow clear back to the separating zone will be responsive to the variation of the pressure in the air box. fuse back up. that will tend to increase the resistance to air flow and the pressure in the air box will increase and so the gates will open to permit more escape of refuse and middlings and thus the operation will be maintained substantially constant. fact that the marble pack in Figure 6 decreases more rapidly in thickness from the receiving to the discharge end than it does in Figure 2. This variationin thickness depends altogether upon the conditions of If too much middlings and re- Attention is also called to the operation, the rate of flow, the character of the coal or material to be treated, its size, etc. The middlings passing through the gate I22 will be discharged through a chute I32, the refuse passing over the coal chute I26 will be discharged through a chute I33.

The pivot 53 Fig. 5 will be held in its slot 58 by a filler block I34, held in place by a set screw I35 after the parts have been assembled so as to make sure that the response to the adjusting means at the receiving end of the air pack will be a proper and controlled one. In Figure 4 is shown the detail of the marble pack. For instance, the lower plate 41 is slotted, the upper plate 48 is perforate. These plates may be of any suitable shape, they may be stamped or they might be built up of wire cloth as the case may be depending altogether upon the circumstances.

It will be understood that substantially all the apparatus except the air box and marble pack is the same no matter what material is being treated. If, for instance, we have a device such as is shown in Figure 2 and we want to treat a different kind of material, finer or coarser as the case may be or different in other characteristics, we would first remove as a. unit that part of the apparatus on the left hand side of Figure 2 and Figure 1 containing the chutes and gates. To do this we would merely disconnect the two turn buckles H3 and I26 from the lever 93 and the chutes, gates and associated parts could be removed asa unit. Then the air box would be lowered until it was supported on the rollers, the locking screws 50 being meanwhile released. Then the air box with its marble pack would he slid forwardly out of the apparatus, first disconnecting the two flexible conduits leading one to the air compressor, the other to the float chamber. Then a difierent air box and marble pack would be put in place, the chute head would be returned, the marble pack would be adjusted and locked in place and operation could be resumed.

Experience shows that the marble pack is the most satisfactory means for controlling the air flow. It can be easily adjusted. It is, simple, does not wear out and gives a nice control of the air resistance. But under some circumstances a, fabric may be used in place of the marbles. In this case a series of fabric layers which may be of wire screen or cloth or any suitable material as indicated in Fig. 11 at I38 would be used.

I claim:

1. A material classifying device comprising a pervious fixed inclined floor, means for feeding a relatively deep stream of material to be classified downwardly therealong, a resistance bed beneath the floor, means for discharging a pulsating current of air upwardly through the resistance bed and the stream of material, a plurality of chutes having horizontal cutting edges opposed to the flow of material, means for manually adjusting the height of each chute with respect to the discharge end of the floor, gates associated with said chutes remote from the fioor, and means automatically responsive to variations in the pressure beneath the resistance bed for controlling the position of said gates.

2. A material classifying device comprising a pervious fixed inclined floor, means for feeding a relatively deep stream of material to be classified downwardly therealong, a resistance bed beneath the fioor, means for discharging a pulsating current of air upwardly through the resistance bed and the stream of material, a, plurality of chutes having horizontal cutting edges opposed to the fiow of material, means for manually adjusting the height of each chute with respect to the discharge end of the floor, gates associated with said chutes remote from the floor. means automatically responsive to variations in the pressure beneath the resistance bed for controlling the position of said gates, and manual means for adjusting the response of said gates to the automatic control means.

3. A material classifying device comprising a pervious fixed inclined floor, means for feeding a relatively deep stream of material to be classified downwardly therealong, a resistance bed beneath the fioor, means for discharging a pulsating current of air upwardly through the resistance bed and the stream of material, a plurality of chutes having horizontal cutting edges opposed to the flow of material, gates associated with said chutes remote from the floor, and means automatically responsive to variations in the pressure beneath the resistance bed for controlling the position of said gates.

4. A material classifying device comprising a pervious fixed inclined floor, means f' 7 feeding a relatively deep stream of material to be classified downwardly therealong, a resistance bed beneath the floor, means for discharging a pulsating current of air upwardly through the resistance bed and the stream of material, a plurality of chutes having horizontal cutting edges opposed to the flow of material, gates associated with said chutes remote from the floor, means automatically responsive to variations in the pressure beneath the resistance bed for controlling the position of said gates, and manual means for adjusting the response of said gates to the automatic control means.

5. A material classifying device comprising a pervious fixed inclined fioor, means for feeding a relatively deep stream of material to be classified downwardly therealong, a resistance bed beneath the floor, means for discharging a pulsating current of air upwardly through the resistance bed and the stream of material, a plate having a relatively large number of apertures substantially larger than the size of the material particles being treated suspended in the stream of material above and generally parallel with the floor.

6. A material classifying device comprising a pervious fixed inclined floor, means for feeding a relatively deep stream of material to be classified downwardly therealong, a resistance bed beneath the floor, means for discharging a pulsating current of air upwardly through the resistance bed and the stream of material, a plate having a relatively large number of apertures substantial- 1y larger than the size of the material particles being treated suspended in the stream of material above and generally parallel with the fioor, and means for imparting to said plate a reciprocatory movement in general parallelism with the plane thereof.

'I. A material classifying device comprising a pervious fixed inclined floor, means for feeding a relatively deep stream of material to be classifieddownwardly therealong, a resistance bed beneath the floor, means for discharging a pulsating current of air upwardly through the resistance bed and the stream of material, and an open work structure suspended in the stream of material above the floor generally parallel to the floor and adapted to partially support the weight of material in the stream.

8. A material classifying device comprising a pervious fixed inclined floor, means for feeding a relatively deep stream of material to be classified downwardly therealong, a resistance bed beneath the floor, means for discharging a pulsating current of air upwardly through the resistance bed and the stream of material, an open work structure suspended in the stream of material above the floor generally parallel to the fioor and adapted to partially support the weight of material in the stream, and means for imparting to such structure a reciprocation in general parallelism with the floor.

9. A material classifying device comprising a pervious fixed inclined fioor, means for feeding a relatively deep stream of material to be classified downwardly therealong, a resistance bed beneath the fioor, means for discharging a pulsating current of air upwardly through the resistance bed and the stream of material, an open work structure suspended in the stream of material above the floor generally parallel to the floor and adapted to partially support the weight of material in the stream, means for imparting to such structure a reciprocation in general parallelism with the floor, a reciprocating feeder adapted to supply material to the floor to form the stream, and drive means for the feeder and the open work structure adapted to impart motion to them in general consonance with the rate of pulsation of the air current.

' 10. A material classifying device comprising a housing open at the bottom, means at one end for supplying material to be classified thereto, means at the other end for withdrawing classified material therefrom, and a closure for the open bottom of the housing comprising an air box and an air pervious high resistance bed integral therewith, the box and bed being removable from the housing, the bed being immediately adjacent the -stream of material as it passes through the housing.

11. A material classifying device comprising a housing open at the bottom, means at one end for supplying material to be classified thereto, means at the other end for withdrawing classified material therefrom, a closure for the open bottom of the housing comprising an air box and an air pervious high resistance bed integral therewith, the box and bed being removable from the housing, and means for supplying a pulsating current of air under pressure to the box whereby the air passes upwardly through the resistance bed 'and through a stream of material traveling therealong, the bed being immediately adjacent the stream of material was it passes through the housing.

12. A material classifying device comprising a housing open at the bottom, means at one end for supplying material to be classified thereto, means at the other end for withdrawing classified material therefrom, a closure for the open bottom of the housing comprising an air box and an air pervious high resistance bed integral therewith, the box and bed being removable from the housing, means for supplying a pulsating current of air under pressure to the box whereby the air passes upwardly through the resistance bed and through a stream of material traveling therealong, the bed being downwardly inclined from the feed to the discharge end of the housing, and means for adjusting the angle of inclination of the bed, the bed being immediately adjacent the stream of material as it passes through the housing.

13. In a material classifying device, a main frame, a housing carried thereby, a feeder and pulsating air supplying means permanently mounted on the main frame, means removably associated with the housing for receiving and distributing the treated material, an air box having integral therewith an air resistance bed, an air pervious fioor removably mounted on the frame and adapted to close one side of the housing, a pneumatic control means for the distributing and receiving devices permanently mounted on the housing, and a flexible removable connection between the air supply means and the air box and between the air box and pneumatic control means.

14. A material classifying device comprising a main frame, a housing mounted thereon, rollers carried thereby, a combined air box and material supporting deck adapted to be removably positioned beneath the housing to close the open bottom thereof, means for causing the air box to travel along said rollers into register with the housing comprising a Windlass, a sheave, a cable extending from the Windlass over the sheave and anchored on the air box, and a detachable pivot support for the lower end of the air box, the Windlass, sheave and cable apparatus being adapted to raise and lower the opposed end of the air box to adjust the angularity of the matebottom of the housing,

rial supporting deck.

15. A material classifying device comprising a main frame, a housing mounted thereon, rollers carried thereby, a combined air box and material supporting deck adapted to be removably positioned beneath the housing to close the open bottom thereof, means for causing the air box to travel along said rollers into register with the housing comprising a windlass, a sheave, a cable extending from the Windlass over the sheave and anchored on the air box, a detachable pivot support for the lower end of the air box, the windlass, sheave and cable apparatus being adapted to raise and lower the opposed end of the air box to adjust the angularity of the material supporting deck, and means for locking the air box in adjusted position in the housing.-

16. A material classifying device comprising a housing, open at the bottom, means at one end for supplying material to be classified thereto and at the other end for withdrawing classified material therefrom, a removable air box closing the there being integral with the air box a pervious floor upon which the material is supported and along which it travels and a high resistance air pervious pack beneath the fioor and between it and the remainder of the box, and means for supplying a pulsating current of air under pressure to the box.

17. A material classifying device comprising a housing, open at the bottom, means at one end for supplying material to be classified thereto and at the other end for withdrawing classified material therefrom, a removable air box closing the bottom of the housing, there being integral with the air box a pervious fioor upon which the material is supported and along which it travels and a high resistance air pervious pack beneath the floor and between it and the remainder of the' for supplying material to be classified thereto and at the other end for withdrawing classified material therefrom, a removable air box closing the bottom of the housing, there being integral with the air box a pervious fioor upon which the material is supported and along which it travels and a high resistance air pervious pack beneath the floor and between it and the remainder of the box, and means for supplying a pulsating current of air under pressure to the box, the floor being downwardly inclined from the supply end thereof, means for adjusting the inclination of the floor, and rollers upon which the box rests when the inclination has been reduced to a minimum whereby the box may be longitudinally withdrawn from the housing.

19. A material classifying device comprising a. housing, open at the bottom, means at one end for supplying material to be classified thereto and at the other end for withdrawing classified material therefrom, a removable air box closing the bottom of the housing, there being integral with the air box a pervious fioor upon which the material is supported and along which it travels and a high resistance air pervious pack beneath the floor and between it and the remainder of the box, means for supplying a. pulsating current of air under pressure to the box, the floor being downwardly inclined from the supply end thereof, means for adjusting the inclination of the fioor, rollers upon which the box rests when the inclination has been reduced to a minimum whereby the box may be longitudinally withdrawn from the housing, and adjusting means comprising a Windlass, a pulley on the housing, and a cable passing from the windlass over the pulley to the box and anchored thereupon, the

means for withdrawing the classified material from the housing being in part in line with the box and adapted to be removed to permit removal of the box.

20. Means for classifying material according to weight, comprising an air box, means for supplying air under pressure in a pulsating stream thereto, a high resistance air pervious bed associated with the box, means for supplying a stream of material to be separated to and causing it to travel along the upper surface of said bed, means immersed within the stream for guiding such material along lines parallel with the surface of the bed, and means at the discharge end of the stream for separating such stream into a plurality of separate streams, one superposed above the other and containing materials of generally homogeneous but different specific gravities.

21. Means for classifying material according to weight, comprising an air box, means for supplying air under pressure in a pulsating stream thereto, a high resistance air pervious bed associated with the box. means for supplying a stream of material to be separated to and causing it to travel along the upper surface of said bed, means immersed within the stream for guiding such material along lines parallel with the surface of the bed, means at the discharge end of the stream for separating such stream into a plurality of separate streams, one superposed above the other and containing materials of generally homogeneous but difierent specific gravities, and automatic means responsive to variation in the pressure in the box controlling the rate of flow of each stream separately.

22. In a materials separating machine, a main supporting housing, means permanently associated therewith for supplying material to be treated to the housing, for supplying fluid undei' pressure to the housing and for imparting to such fluid a pulsating action, an air box having a resistance bed adapted to be removably and adjustably mounted in the housing with the bed in such position that material to be separated are discharged upon and travel along said bed, means removably associated with the housint and the air box for horizontally dividing the stream of material into a plurality of layers and automatic means responsive to variation in pressure in the air box for controlling the rate of flow of at least one of said streams.

23. A material classifying device comprising a pervious fioor, means for feeding a relatively deep stream of material to be classified therealong, means for discharging a current of air upwardly through the floor and the stream of material, and means embedded in the stream of material generally parallel with the floor for preventing localized air blasts through the bed of material, said means comprising a thin plate generally parallel with the floor having a relatively large number of apertures therethrough substantially larger than the maximum size of the particles being treated and means for giving this plate a controlled movement whereby the material as it, travels is gently stirred.

24. In an air separator for removing impurities from coal, an inclined trough, a resistance bed forming the bottom of said trough, an air chamber beneath said bed, means for delivering crude coal to the upper end of said trough, means for delivering air to said chamber under pressure, whereby currents of air are forced up through said bed to cause the coal and refuse. mixed therewith to fiow down said trough, the coal and refuse gradually separating into different strata due to the difference in their specific gravities, a plurality of chutes arranged to receive material from different strata, respectively, at the lower end of said trough, gates for partly blocking said chutes below the bottom of said trough whereby the chutes are maintained full of material, and mean responsive to an increase in the air pressure in said chamber due to excess accumulation of material in the trough for increasing the opening of said gates.

25. In an air separator for removing impurities from coal. an inclined trough, a resistance bed forming the bottom of said trough, an air chamber beneath said bed. means for delivering crude coal to the upper end of said trough, means for delivering air to said chamber under pressure,

. whereby currents of air are forced up through said bed to cause the coal and refuse mixed therewith to fiow down said trough, the coal and refuse gradually separating into different strata due to the difference in their specific gravities, a plurality of chutes arranged to receive material from different strata, gases for controlling the flow of material down said chutes, a common mechanism responsive to variations of air pressure in said chamber for controlling said gates simultaneously, and means for adjusting each gate independent of the other.

26. In an air separator for removing impurities from coal, an inclined trough, a resistance bed forming the bottom of said trough, an air chamber beneath said bed, means for delivering crude coal to the upper end of said trough, means for delivering air to said chamber under pressure, whereby currents of air are forced up through said bed to cause the coal and refuse mixed therewith to flow down said trough, the coal and refuse gradually separating into different strata due to the diflerence in their specific gravities, a chute for receiving the lower strata consisting of refuse, a chute for receiving the next strata above consisting of mixed coal and refuse, gates in the chutes for maintaining them full and overflowing at all times to thereby maintain the requisite depth of material in the trough at the lower end, and means responsive to variation of air pressure in said chamber for controlling said gates.

27. In an air separator for removing impurities from coal, an inclined trough, a resistance bed forming the bottom of said trough, an air chamber beneath said bed, means for delivering crude coal to the upper end of said trough, means for delivering air to said chamber under pressure, whereby currents of air are forced up through said bed to cause the coal and refuse mixed therewith to flow down said trough, the coal and refuse gradually separating into different strata due to the difierence in their specific gravities, a perforated member suspended in the said trough substantially parallel to the bottom thereof and at approximately the upper level of the refuse strata, the openings in said member being large enough to readily pass the largest pieces of coal and refuse, and means for imparting a reciprocating motion to said member to tir the material and facilitate stratification thereof.

EARL STUMP.

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