US771805A - Dry separator. - Google Patents

Description

No. 771,805. PATENTED OUT. 11, 1904. F. O. BLOOM.

DRY SEPARATOR.

APPLICATION FILED OCT. 19, 1903.

4 SHEETS-SHEET 1.

N0 MODEL Wt FOE 70,0170. I a f I y j a r I v a e/qlforgz ys No. 771,805. PATENTED OCT. 11,-1904. I I F. O. BLOOM.

DRY SEPARATOR.

NO EL APPLICATION FILED OUT. 19, 1903.

4 SHEETS-SHEET 2.

@AIfmgeys No. 771,805. PATENTED OCT. 11, 1904.

P. 0. BLOOM.

DRY SEPARATOR.

N0 MODEL? APPLICATION FILED 00119, 1903.

4 SHEETS-SHEET 3.

WT J 30$ Z00 7 2/,

1 1925s v 1) (:1 OP, (1? y Patented October 11, 1904.

PATENT OFFICE.

FRED O. BLOOM, OF HELENA, MONTANA.

DRY SEPARATOR.

SPECIFICATION forming part of Letters Patent No. 771,805, dated October 11, 1904.

Application filed October 19, 1903. Serial No. 177,647. (No model.)

To all whom it may concern.-

Be it known that I, FR D O. BLOOM, a citizen of the United States, residing at Helena, in the county of Lewis and Clarke and State of Montana, have invented a newand useful Dry Separator, of which the following is a specification.

This -invention relates to apparatus for separating native gold in the form of small nuggets, flakes, and grains from sand and gravel by means of screening and the use of an airblast in connection with suitable receiving devices in which the gold is caught owing to its high specific gravity.

The object of the invention is to provide in a simple readily-portable apparatus of the class described improved means for separating native gold from sand and gravel without the use of water and with the expenditure of a comparatively small amount of power.

A further object of the invention is to improve gold-separators of the type specified by making them susceptible of more rapid and efficient action than similar devices as heretofore constructed.

In its entirety the invention comprises a suitable framework mounted for convenience in transport upon a wheel and provided with handles similar to those of a wheelbarrow, screening devices of various forms, means for agitating the sand and gravel while in the apparatus, drying devices, means for producing a blast of air, and suitable receiving devices.

The preferred form of embodiment of the invention is illustrated in the accompanying drawings, forming part of this specification, in which corresponding parts are designated by similar characters of reference throughout and the novel features of the invention are specifically pointed out in the appended claims.

In the drawings, Figure l is a view in perspective of the complete apparatus set up for operation. Fig. 2 is a vertical longitudinal section through the complete apparatus, showing the parts in position for operation, but showing the supporting-Wheel lowered into contact with the ground in the position taken when the apparatus is to be transported. Fig. 3 is a view in side elevation, showing the side not exposed in Fig. 1. Fig. 4 is a vertical transverse section on the line 4 4: of Fig. 2 looking in the direction indicated by the arrows. Fig. 5 is a vertical longitudinal section through the apparatus with the hollow cylinder and sluice-screen removed and the deflector depressed for the final clean-up. Fig. 6 is a detail view in perspective of the sluice screen detached. Fig. 7 is a detail view in perspective of the carrier for the sluice-screen and the apron and chute substituted for the sluice-screen for the final cleanup, as shown in Fig. 5.

In the drawings, F designates the supporting-frame of the machine, which may be of any preferred form, but which as ordinarily constructed will comprise side walls 1 1, mounted on uprights 2 2 2 2 and connected by suitable cross-pieces at the top and bottom, as 3 3 8 8. At the rear end of the machine on one of the cross-pieces 8 is supported a hopper f, provided on its front side near the bottom with a discharge-opening 5, which may be closed by means of a gate 6, arranged in the hopper and operated in any preferred manner. A chute 7 is arranged at the bottom of the opening 6 to transfer the material discharged through said opening to a revolving cylinder 8, which is hollow, as best seen in Fig. 2, is composed preferably of sheet metal, and throughout the half of its length remote from the hopper and adjacent to the forward end of the machine is pierced by perforations spaced apart, as shown in the drawings. The perforations are of two sizes. The greater number of perforations, which are designated 9, are preferably three-sixteenths of an inch in diameter, and a smaller number of perforations 10, arranged in two rows adjacent to the forward or discharge end of the cylinder, are preferably one-quarter of an inch in diameter. The cylinder 8 is supported by means of diametrically-arranged supporting-bars ll inside the cylinder and a shaft 12, which passes through the bars 11 and has its ends supported in suitable bearings. At its rear or receiving end the cylinder is provided with an inwardly-disposed flange 13 of sufficient width to prevent the escape of the contents of the cylinder at that end, and in order to insure sufficient agitation of the sand and gravel within the cylinder to thoroughly loosen and separate the particles thereof longitudinallydisposed plates are secured within the cylinder in radial planes, as shown at 14. These plates 14 extend only throughout the imperforate part of the cylinder, so that at the for- Ward end of the cylinder the sand and gravel may come into uninterrupted contact with the perforated cylinder-wall. A flange 15 is provided at the forward end of the cylinder to prevent the escape at the end of the cylinder of particles small enough to pass through the perforations provided in the cylinder-wall; but the escape of large masses is permitted, and a chute 16 is supported in the frame adjacent to the forward end of the cylinder for such masses to pass over.

The axis of the cylinder is inclined somewhat, as will be seen from an inspection of the drawings, and in order that the pitch of the axis may be suited to the character of the sand and gravel under treatment the rear end of the axle is journaled in a box 17, from the side, of which project studs 18,which rest in notches 19, provided in a pair of parallel supportinglugs 20, which project from a transverse bar 21, adjustably mounted at the front and near the bottom of the hopper 4. The bar 21 is supported by means of bolts passing through the ends thereof and also through openings provided for the purpose in brace members 22, by which the hopper is secured in position on top of the machine. The forward end of the cylinder-axis rests in a notch 23 in a supporting-lug 24, bolted to the upper forward crosspiece 3. From the arrangement justdescribed -it will be apparent that the rear end of the cylinder at which the sand and gravel are received may be raised or lowered, as desired, in order to secure the proper pitch for the cylinder-axis. v

Material is fed from the hopper to the cylinder by means of the gate and chute above mentioned and in the cylinder is subjected to agitation by means of the plates 14 when the cylinder is rotated. The means for rotating the cylinder comprises a belt 25, encircling the cylinder near its rear end and driven by means of a small pulley 26, which is mounted on a short shaft 27, supported in bearingblocks 28 on the exterior of the machine-frame and provided at one extremity with a bevelgear 30, in mesh with a larger bevel-gear 31 upon the main driving-shaft ofthe machine, which is shown at 32. The shaft 32 is suitably journaled in bearing-blocks 33 at the rear end of the machine and has secured to the end opposite the bevel-gear 31 a large disk 34, provided near its circumference with a handle 35,

' by means of which motion is imparted to the disk.

When the sand and gravel are fed to the cylinder and subjected to agitation therein, the particles are thorougl'ily separated and the sand and the particles of gold and gravel, which are small enough to pass through the perforations 9 and 10 in the cylinder-wall, drop through said perforations into a dryingpan 36, which is disposed beneath the cylinder and suspended by means of hangers 37, passing through openings formed in the downwardly-turned ends of bars 38, which are bolted to the under side of the drying-pan, as best seen in Fig. 2. The hangers 37 are of substantially the same form, each comprising a middle horizontal portion 39,merging into upturned suspension portions 40- at the ends. each of said upturned portions having a laterally-disposed terminal 41, adapted for engagement with a half-bored bearing-block 42, which is fixed upon the upper surface of a side wall of the machine-frame. The hangers 37 are sufficiently resilient for the terminals 41 to be swung into the sockets afl orded by the half-bored bearing-blocks 42, and so prevent lateral movement of the drier 36. The drier 36 is preferably a sheet-metal pan of rectangular form, as shown, set on an incline from the front toward the rear of the machine and provided near its rear end with a transverse slot in the bottom at 43, which will preferably be about one-quarter of an inch wide. The slot 43 is disposed above the sieve-basket 44, removably'secured to the bottom of the drier, so that it may be exchanged for a basket of different mesh. The sieve-basket 44 has a pitch preferably of one inch downward toward one side of the machine, where it discharges particles too large to pass through its meshes, and beneath the sieve-basket is arranged a guide-apron 44, discharging at its rear margin.

The material which cannot pass through the meshes of the sieve-basket is discharged at the lower end into a chute 45, which extends through the side wall of the machine and discharges into another chute, 46, secured on the outside of the side wall and extending downward and forward at a rather sharp incline. At the bottom of the chute 46 is provided a Vshaped trough 46*, in which the heavier particles, which will include the gold passing down the chute 46, will lodge, while the lighter particles of small gravel and the like will pass over the trough.

The sieve-'bas-ket is carried by the drier and both are vigorously shaken during the operation of the machine by means of a claw motion operated from the main shaft of the machine. At the rear end of the drying-tray there is secured a rearWardly-extending hook or claw 47, beneath which is arranged a spring 48, which holds the claw in position for engagement by means of arms 49 in the form of loops which project radially at equal intervals through a hub 50 upon the main shaft of the machine. Suspended behind the hub 50 with its arms is a pivoted holder 51, whose lower end is adapted to engage the claw 47 and hold it between the engagements of the arms with the claw. At the forward end of the drying-tray is provided a buffer mechanism comprising downwardly-disposed lugs 53, through which pass guide-rods 54, which are mounted upon a cross-bar on the machineframe. Coiled springs 55 encircle the rods 54 and form a yielding check for the movement of the drying-tray, which is arrested in its movement by contact of the lugs 53 with said springs. Tension-springs 56 serve to supplement the action of gravity in drawing the drying-tray toward the buffer-springs 55, and these tension-springs are secured at one end to the tray and at the other end are connected with screw-eyes 57, secured in the ends of rods 54.

The thorough drying of the sand and gravel in the tray is effected by means of a hydrocarbon-burner 60 of any suitable form, which is schematically illustrated in Fig. 2 and is supplied with fuel from a reservoir or tank 61, supported on the outside of the machineframe.

The same movement of the main shaft of the machine which imparts movement to the cylinder 8 to agitate the sand and gravel therein also imparts movement to the drying-tray through the claw motion device above described, whose action is as follows: When an arm 50 engages the claw 47, it draws it rearward until the arm passes out of engagement with the claw. The claw will be held in this position for a moment and then will be released by the engagement of the next arm 50, with the holder pivoted above and behind the main shaft in position to frictionally engage the claw when pulled back by one of the arms 50. As soon as the holder is disengaged the tray will be drawn forward against the buffers by the action of the tension-springs, and sand and gravel on the bottom thereof will slide toward the slot near the rear end of the tray, through which the dry sand and gravel escape to the sieve-basket, as above explained. The material too large to pass through the meshes of the sieve-basket is disposed of at the outside of the machine, as already explained, and the remainder, which passes through the meshes of the sieve-basket, falls upon an apron 68 at the upper end of a separating or sluice screen, (designated generally as 64.) The separatingor sluice screen 64 slopes from the rear of the machine toward the front and comprises side bars 65 and screen- sections 66, 67, and 68, arranged in the order mentioned, passing from the apron 63 at the rear of the sluice-screen toward the front and separated by narrow slits from each other and from the lower forward portion of the sluice, at the end of which is provided a V-shaped trough 69. The sluice-screen is supported upon a carrierframe 70, upon which it is secured by thumbscrews 71, as seen in Fig. 2. The carrierframe 7 O is incased at the sides with canvas (shown at 72) and is supported at the rear or upper end by compression-springs 7 3 and at the lower end by tension-springs 74, adjustably mounted upon the side walls of the frame by means of screws 7 5, arranged in slotted supporting-plates 76 and forming means for regulating the pitch of the carrier-frame. The carrier-frame is inclined downward toward the front of the machine, so that the material which does not pass through the meshes of the screen-sections of the sluicescreen or through the slots between said sections will pass down toward the forward end of the machine to lodge in the trough at the end of the sluice-screen or be discharged over it.

The carrier-frame being supported entirely on springs and being incased at the sides in canvas is susceptible of movement in all directions, and in the operation of the device a lateral and vertical vibratory movement is imparted to the carrier-frame by means of a bar 77, pivotally mounted in a bracket 78 on the outside of the machine-frame and extending through an eyebolt 79, which projects through the side wall of the machine-frame and engages a lug 80 on the under side of the carrier-frame. The bar 77 is engaged by springs 81 and. 82, the latter of which has means for adjusting the tension thereof, and the means for rocking the bar comprises a plurality of stops 83, preferably three in number, which are screwed into the face of the pulley over which runs the belt for imparting movement to the cylinder 8.

To receive the particles which pass through the sluice-screen, a receiving box or tray 84 is provided beneath the sluice-screen. Thebox 84 is open at its rear end, and there is arranged across the open rear end a pivoted deflector 85, whose use will presently appear. In the bottom of the box in front of the deflector 85 are a plurality of riffles 86, and near the forward end is an inclined plate- 87, whose upper edge is separated from the front wall of the 4 box by a space of two or three inches.

In front of the box 84 there is arranged a fan 90, which may be of any preferred construction, but which in this instance consists of a plurality of radially-arranged blades 91, operating in a casing 92 with openings in the ends, as shown at 93. The blades 91 aresupported upon a shaft 94, and the shaft is supported in suitable bearing-blocks 95, provided on the machine-frame in suitable relation to the casing 92. At one end of the shaft 94 is provided a small pulley 96, over which runs a belt 97, which is supported upon the periphery of the disk 34 on the main shaft and which is adapted when rotation is imparted to the main shaft to drive the fan-shaft 94 at a high rate of rotation. The fan-casing 92 is open at the forward side, so that the blast from the fan is driven normally forward into the machine, and its direction is controlled by means of the pivoted deflector 85, which may be regulated in position by means of a pointed indicatingarm 98, which moves over a segmental surface 99 on the outside of the frame and which is provided with means for securing it in any desired position, the securing means illustrated consisting of a screw 100, mounted in the indicating-arm and adapted to be brought into engagement with the surface over which the arm travels.

As material passes downward from the sievebasket and apron 44 it falls on apron 63 and then passes to screen-section 66, which is of coarser mesh than that of the screen-section 67, which in turn is of coarser mesh than section 68. The screening of all of the material passing through the sieve-basket by screensection 66 is, however, prevented by the blast from the fan, which is deflected upward by means of the deflector 85, so that it meets the traveling particles at an oblique angle and serves to raise all of the lighter particles from the screen 66. The heavier particles pass on to the coarse screen, and those of sufficiently small diameter are caused to pass through by the agitation imparted to the sluice-screen by means of the bar 77 and the members associated therewith. The particles which are too large to pass through the meshes of screensection 66 roll on toward the lower end of the sluice-screen to be caught in the trough at the end or discharged over it. The smaller particles of material passing through the sievebasket are prevented by the blast from the fan from passing through screen-section 66, being carried on by the blast sufficiently to fall on screen- sections 67 and 68, the lightest particles being carried farthest and falling upon the latter screen. By means of this arrangement of parts effective separation of the fine particles of gold and sand is obtained, because the fine gold is of suflicient weight to fall, in spite of the blast from the fan, upon the screen -sections and pass through them or through the slots between the screen-sections if the gold is in the form of flakes. The greater part of the sand, however, is too light to fall against the blast on a screen whose meshes are large enough to permit it to pass through, and consequently the material which passes through the meshes of the screen-sections of the sluice-screen or through the slots between said screen-sections will contain a large percentage of gold and but a small amount of other material of lower specific gravity. Of the particles which are too large to pass through the meshes of the sieve-basket or through the meshes of the sluice-screen the particles of gold on account of their high specific gravity will be caught in the troughs provided at the end of chute a6 and at the end of the sluice-screen, while the lighter particles of sand or gravel will for the most part be carried by their momentum over said troughs and discharged from the machine.

When the machine has been in operation for from the machine by lifting its aXis and the adjustable bearing-block thereon out of the notches in the supporting-lugs, and the accumulated material in the receiving-box will be introduced into the drying or feed pan. The machine will then be set in operation again, and the material will be fed through the slot in the bottom of the drying-tray down into the sieve-basket and through its meshes to the apron 101 upon the rear end of the carrierframe, from which it will pass forward and downward along the chute 102 toward the receiving-box. As the material passes from the chute 102' it will be struck by the blast of air from the fan, which is now allowed to pass directly forward by lowering the deflector into the position shown in Fig. 5, and when struck by the blast from the fan the light particles of sand and gravel will be thrown forward against the inclined plate adjacent to the forward end of the receiving-box and the particles of gold will be driven forward along the bottom of the receiving-box to be caught by the riflies thereon. The particles of sand and gravel being of comparatively low specific gravity will be carried upward over the inclined plate near the front of the receivingboX and discharged from the apparatus; but the light particles of gold which may be carried over the riffies will either lodge in the space between the riiiles and the inclined plate or else upon passing up to the top of the inclined plate will drop into the space between the plate and the front end of thereceivingbox, from which space these light particles may easily be collected by tilting the bottom of the inclined plate upward, so as to expose the space in front of it. The material which lodges in the trough at the end of the chute 15 on the outside of the machine will be composed of small nuggets of gold and pieces of gravel of such size that the gold may be easily separated from the gravel by sorting, and no further treatment with the machine will be necessary.

To facilitate the transportation of the machine from place to place,a wheel 103 is mounted in a pivoted frame 104, which is secured between the rear uprights2 and is adapted to be turned to bring the wheel in contact with the ground when it is desired to move the machine and to be turned to allow the uprights to rest on the ground when it is desired to put the machine in operation. A springcatch 104C is provided under the machine to engage the frame 104 when the wheel is lowered to hold the wheel in position to support the machine. Handles 105 are also provided to enable the operator to move the machine in the same manner that a wheelbarrow is moved, these handles being rigidly fastened to the front uprights at a suitable height above the lower-ends thereof.

' From the foregoing description and the drawings illustrative thereof it will be seen that the machine is adapted to effect a thorough separation of the particles of gold from the sand and gravel with which they are mixed and that it may be operated rapidly and effectively with a comparatively small expenditure of power.

The machine is small and easily transportable. It is inexpensive in construction, and contains no parts that are apt to become injured or which in case of injury could not be readily and thoroughly replaced.

The movements of the various parts of the machine are positive and so eflective that a uniform action is obtainable as long as the supply of sand and gravel is continued.

While I have described and illustrated the preferred form of embodiment of my invention, it will be obvious that various changes in the details of construction may be resorted to without departing from the spirit of the invention or sacrificing its advantages, and I do not wish to be limited as to the details of construction, but reserve the right to make such changes as lie within the scope of the appended claims.

Having thus described the construction and operation of my invention, what 1 claim as new, and desire to secure by Letters Patent, is-

1. The combination in apparatus of the class described, of acoarse screen for separating fine particles from the coarser particles, a drier disposed beneath said screen and having a discharge-opening for the dry material, means for simultaneously imparting movement to said screen and said drier, a sieve mounted on the under side of said drier beneath the discharge-opening, and a finer screen disposed beneath said sieve.

2. The combination in apparatus of the class described, of a drier having a discharge-opening in the bottom, means for imparting reciprocatory movement to said drier, a sieve mounted on the under surface of said drier beneath the discharge-opening, said sieve being arranged to discharge coarse materials at one end thereof, and a fine screen disposed beneath said sieve.

3. The combinationin apparatus of the class described, of a drier having a discharge-opening, a sieve beneath said discharge-opening and attached to said drier, apparatus below the sieve for producing a current of air to act downward through the material falling upon said sieve, and means for varying the direction of said blast.

4. The combination in apparatus of the class described, of a rotary screen, a shaft upon which said screen is mounted, a fixed bracket forming a bearing for one end of said shaft, an adjustable bracket, and a bearing-block fitted upon the other end of said shaft and provided with trunnions for engagement with said adjustable bracket.

5. The combination in apparatus of the class described, of a rotary screen, a shaft upon which said screen is supported, a fixed bracket forming a bearing for one end of said shaft, a vertically-adjustable bar at the other end of said shaft, a bracket comprising a pair of notched arms mounted on said bar, and a bearing-block through which said shaft passes havin g trunnions for engagement with the notched arms of said bracket.

6. The combination in apparatus of the class described, of a drying-pan arranged for longitudinal and vertical movement, said dryingpan being disposed on a slight incline and having an opening at the lower end, means for agitating said drying-pan, a sieve attached to said drying-pan below the opening, and a screen disposed beneath said sieve.

7. The combination in apparatus of the class described, of a drying-pan having an inclined bottom and a discharge opening near the bottom of the incline, pivoted hangers upon which said drying-pan is supported, a sieve secured beneath the. opening in said dryingpan, means for imparting a longitudinal oscillatory movement to said pan, and means for screening the material which passes clownward through said sieve.

8. The combination in apparatus of the class described, of a drying-pan mounted on swinging supports and having an inclined bottom with a discharge-opening at the lower end thereof, means for positively moving said pan in one direction, a spring to retract said pan when released, and a screen disposed beneath said discharge-opening to receive the material passing downward therethrough.

9. The combination in apparatus of the class described, of a drying-pan having a dischargeopening in the bottom near the forward end, means for slowly advancing the pan, and means for suddenly retracting the pan after each advance, and a screen disposed beneath the discharge-opening in said pan.

10. The combination in apparatus of the class described, of a drying-pan having an opening in the bottom near one end, a hook projecting from the end adjacent to the opening, means for engaging the hook at intervals to advance the pan, means at the other end for suddenly retracting it, and a screen disposed beneath the discharge-opening in the bottom of said pan.

11. The combination in apparatus of the class described, of a drying-pan having an opening in the bottom thereof near one end, a resiliently-supported hook attached to the end adjacent to the opening, means for inter mittently engaging said hook to advance the pan, means at the other end of the pan for suddenly retracting it, and a sieve secured beneath the opening in the pan.

12. The combination in apparatus of the class described, of a movably-supported pan having an opening near the forward end, a sieve secured to the bottom of said pan beneath said opening, a resiliently-supported hook projecting from the forward end of said pan, a member adapted to engage said hook intermittently to advance the pan, a holder adapted to engage said hook at the end of each advance to prevent immediate return of the pan, said holder being adapted for engagement by said member just previous to its next engagement with the hook, means at the opposite end of the pan for suddenly retracting it when said holder is disengaged from the hook, and a screen disposed beneath said sieve.

13. The combination in apparatus of the class described, of a movably-supported pan having a discharge-opening in the bottom near the forward end, a resilicntly-supported hook projecting forward from said pan, a rotatable member havinga plurality of arms adapted for successive engagement with said hook, a pivoted holder adapted to engage said hook when one of said arms passes out of engagement therewith and adapted to be released by the approach of the next arm upon said rotary member, means for suddenly retracting the pan upon the disengagement of the holder and .the hook, and a screen disposed beneath the discharge-opening in said pan.

14. The combination in apparatus of the class described, of a movably-supportcd pan having a discharge-opening near the forward end thereof, means for positively advancing said pan at intervals, means for suddenly retracting said pan after each advance, a yield ing buffer to gradually check the movement of the pan when retracted, and a screen disposed beneath the discharge-opening in said pan.

15. The combination in apparatus of the class described, of a movably-supported pan having a discharge-opening near the forward end thereof, means for advancing the pan slowly at intervals, means for holding the pan momentarily in advanced position, means for suddenly retracting the pan when the holding mechanism is released, and a screen disposed beneath the discharge-opening in said pan.

16. The combination with a movably-supported pan having a discharge-opening near the forward end, of means for gradually advancing the pan at intervals, means for holding the pan momentarily advanced, said means being released by the operation of the pan-advancing means, means for suddenly retracting said pan as soon as the holding means is re leased, and a screen disposed beneath the discharge-opening in said pan.

17. The combination in apparatus of the class described, of a movably-supported pan having a discharge-opening in the bottom thereof near the forward end, heating devices beneath said pan, means for agitating said pan to effect the feed of material forward along the bottom thereof and downward through said opening, a sieve attached to said pan and discharging laterally, and a screen disposed beneath said sieve.

18. The combination in apparatus of the class described, of a pan having a dischargeopening in the bottom near the forward end, heating means beneath said pan, means for agitating the pan to effect the discharge of material through said opening, a sieve secured to said pan beneath the discharge-opening and discharging at one side, and a movable screen disposed beneath said sieve.

19. The combination in apparatus of the class described, of a drying-pan having a dis charge-opening in the bottom thereof, a sieve attached to said pan beneath said opening and having a pitch toward one end to discharge therefrom materials too large to pass through the sieve, and means for agitating said pan to feed material to said discharge-opening.

20. The combination in apparatus of the class described, of a drying-pan having an opening in the bottom thereof, a sieve attached to said pan beneath said opening and arranged to discharge at one end the particles too large to pass through the sieve, an inclined chute at the end of the sieve to receive the particles discharged therefrom, a catchtrough at the lower end of said chute to receive particles of high specific gravity, and means for agitating the pan to feed materials tl'irough the opening in the bottom thereof.

21. The combination in apparatus of the class described, of a sluice-screen comprising an apron at one end to receive material, a series of perforated screen-sections adjacent to said apron to receive material therefrom, said perforated sections having meshes of different sizes and an imperforate portion beyond the perforated portion to receive the material which does not pass through the perforated portion, and means for directing a blast of air against the under side of the perforated portion of the screen.

22. In an apparatus of the class described, a sluice-screen comprisingaplurality of screensections having meshes of different sizes, the screen sections being arranged to present meshes of decreasing sizes for the passage of the material as it moves from the receiving end of the screen toward the discharge end, and an imperforate bed beyond the screensections to receive the material which does not pass through the screen-sections.

23. In an apparatus of the class described, a sluice-screen comprising a plurality of screensections having meshes of different sizes and separated by narrow slits, and an imperforate bed beyond the screen-sections to receive the material which does not pass through the screen-sections.

24. The combination in apparatus of the class described, of a sluice-screen having near one end a plurality of screen-sections of different-sized meshes, said screens being arranged with the section of coarsest mesh nearest the end of the screen and with the meshes of the succeeding sections gradually decreasing in size, means for feeding material onto the screen-section of coarsest mesh, and means for directing a blast of air against the under side of said screen-sections and making the intensity of the blast greatest under the screensection of coarsest mesh.

25. The combination in apparatus of the class described, of a sluice-screen supported therein for vertical and lateral movement, and means for imparting movement to said screen comprising a lever pivotally mounted on the outside of the apparatus and operatively connected with said screen, a spring engaging said lever to hold one end normally away from the side ofthe apparatus, and a revolving member having a plurality of arms adapted for successive engagement with said lever to move it inward against the action of the spring.

26. The combination in apparatus of the class described, of a sluice-screen, means for varying the pitch of said sluice-screen, means for directing a blast of air against the under side of said screen, means for varying the direction of said blast, and means for agitating said screen.

27. Thecombination in an apparatus of the class described, of an inclined sluice-screen, a trough secured at the lower end of said screen to receive heavy particles too large to pass through the screen, means for agitating said screen, means for directing a current of air against the under side of said screen where material is fed to it, and a receiving-box beneath the screen to receive all material pass ing therethrough.

28. The combination with a screen,of means fon'iagitating said screen, means for directing a blast of air against the under side of said screen, a box beneath the screen to receive material passing downward therethrough, and a pivoted plate in the end of said box to control the direction of said blast of air.

29. The combination in apparatus of the class described, of a screen, a box disposed beneath said screen to receive material passing downward therethrough, means at the end of said box for producing a blast of air and directing the same forward along the bottom of said box, and a pivoted plate at the end of said box adjacent to the said blast-producing 111621518 whereby said blast may be directed up- Val 30. The combination in apparatus of the class described, of a receiving-box having a pluralityof transverse riflies and an inclined plate near one end of the box, mechanism for directing a blast of air longitudinally of the box over the bottom thereof, and means for feeding screened material into the box from above.

31. In an apparatus of the class described, a receiving-box open at one end and closed at the other, an inclined plate adjacent to the closed end but spaced slightly therefrom, and means for directing a current of air from the bottom of the box toward said inclined plate.

32. The combination in an apparatus of the class described, of areceiving-box open at one end and closed at the other, a plate pivoted at its upper margin and arranged transversely of the box at a slight distance from the closed end said plate having its free margin resting normally upon the bottom of the box and presenting an inclined surface, and means for directing a blast of air longitudinally of the box over the bottom thereof.

In testimony that I claim the foregoing as my own I have hereto affixed my signature in the presence of two' witnesses.

FRED O. BLOOM.

Witnesses:

R. DEMENT, J. L. C LLAHAN.

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