US2221008A - Apparatus for separating materials - Google Patents

Description

Nov. 12, 1940. .1. A. TRAYLOR APPARATUS FOR SEPARATING MATERIALS Filed Dec. 13, 1937 2 Sheets-Sheet 1 INVENTOR uWfl/V ,4. 764720,?

BY I A A IT ORNEf Nov. 12, 1940. J. A. TRAYLOR APPARATUS FOR SEPARATING MATERIALS Filed Dec. 13, 1937 2 Sheets-Sheet 2 INVENOR ua/m/ A. mmae Patented Nov. 12, 1940 UNITED STATES PATENT OFFICE hand, Tessie S. executors of said John Application December 13,

7 Claims.

My invention relates to apparatus for separating from mixtures of a plurality of different kinds of materials, certain selected ones of said materials desired to be removed from the remainder by a flotation and washing process.

In the separation of selected materials from a mixture thereof with other materials, for example, separating minerals or mineral salts from each other or' from ores in which they are found, it is common practice to reduce the mixture to a predetermined state of fine division and to add thereto enough water to form a pulp of any desired consistency and to then treat the pulp in such manner as to float the selected materials to the surface of the pulp and thus remove them from.the remainder of the materials in the pulp.

It is an object of my invention to provide a method of treating such pulp to cause agitation and aeration of the pulp to assist in the flotation 20 of the materials selected to be removed.

Another object of my invention is to provide a method of treating a pulp of the character set forth, in which the pulp is spread out in a relatively thin layer and in which the pulp is passed repeatedly through a screen disposed above the surface of the pulp in such manner as to cause the repeated passage of the pulp through the screen to whip air into the pulp to produce a froth which will float the selected materials to 30 be removed.

Another object of my invention is to provide a method of flotation separation of certain selected materials from a pulp of the character described, wherein a relatively thin layer of the pulp is so agitated as to be repeatedly passed through a screen suspended above the pulp to thereby whip a froth upon the pulp capable of floating the selected materials.

Another object of my invention is to provide a 40' method of the character described, wherein the pulp is allowed to flow over a surface in a relatively shallow stream and in which the surface is so vibrated or shaken as to repeatedly toss the pulp into the air sufliciently tocause it to become 45 self-aerated.

Another object of my iiiven'tion is to provide a method of thecharacter set forth in the preceding paragraph, wherein additional air or other gases may be introduced intothe pulp from other sources to assist in the aeration or to supply gaseous reagents desirable for the separation of certain materials from others of the materials in the pulp.v i

: Another object of my invention is to provide a 55 method of separating selected materials from a Traylor,

and John B. Traylor, A. Trayior, deceased 1937, Serial No. 179.444

pulp of the character set forth, in which the pulp is allowed to flow over a surface in a relatively thin layer and whipping the surface of said pulp by relative movement of the surface and a screen suspended above the surface in such manner that at least a portion of the pulp will be repeatedly thrown through the screen, the froth so produced upon the pulp being allowed to flow along the upper surface of'the screen and so be separated from the remaining pulpr Another object of my invention is to provide an apparatus for flotation separation of selected materials from a pulp of the character described, wherein a relatively shallow pan or trough is provided over which a stream of pulp may pass with means for vibrating or shaking the pan at any predetermined rate to produce a relatively vialent agitation of the pulp during its passage over the pan, with means for separating the froth created bysuchagitation from the remainder of the pulp.

Another object of my invention is to provide an apparatus of they character described wherein the pan employed is provided with heaters or other devices projecting into the stream of pulp flowing over the pan forlproducing rillles and agitation of the pulpin addition to the agitation thereof caused by the vibration or shaking of the pan.

Another object of my invention is to provide an apparatus of the character described wherein the pan defining the surface over which the pulp may pass is so constructed as to permit introduction therethrough of air or other gaseous material may be introduced into the stream of pulp while it is flowing over the surface.

Another object of my invention is to provide an apparatus of the character described, wherein a screen is suspended above the pan surface and spaced therefrom in such manner that at least a portion of the stream of pulp will be forced repeatedly through the screen by the agitation of the stream of ,material to assist in the self-aeration of the material and to provide a surface over which the froth may flow to thereby permit a ready separation of the froth from the remainder of the pulp.

Another object of my invention is to provide an apparatus of the character described, wherein a screen surface is suspended above the pan sur-- face and the screen or pan or both are vibrated or shaken relative to each other in such manner astocauseatleastaportionofthestreamof pulp to repeatedly pass through the screen and 55 my method and apparatus to cause the whipping or beating of finely divided air into the pulp.

Another object of my invention is to provide an apparatus of the characterdescribed, wherein the pan surface is provided with a plurality of upwardly projecting obstructions extending transversely of the direction of movement of the stream of pulp over the surface for the purpose of assisting in the agitation of and the tossin of at least a portion of the pulp into the air.

Other objects of my invention will be apparent from a study of the following specification read in connection with the accompanying drawings, wherein Fig. 1 is a top plan view of a flotation separation apparatus constructed in accordance with my invention.

Fig. 2 is a vertical sectional view taken alon line lIII of Fig. 1.

Fig. 35is a fragmentary vertical sectional view similar to Fig. 2 and illustrating a modified form of flotation separation apparatus which may be employed in the practice of my invention.

Fig. 4 is a vertical sectional view similar to Fig. '7 is a detail sectional view illustratingthe manner in which the filter pad employed in the form of thedevice shown in Fig.5 may be constructed and arranged in my flotation separation 40 apparatus.

Fig. 8 is a fragmentary sectional view similar to Fig. 2 illustrating the manner in which the screen may be suspended independently of the pan or surface over which the pulp material may flow.

Fig. 9 is a vertical sectional view similar to Fig. 2 and illustrating a still further modified form of my flotation separation apparatus.

Fig. 10 is a detail vertical sectional view of one type of mechanism which may be employed to. agitate or shake the apparatus illustrated in Figs. 1-9. a

For the purpose of assisting in a ready understanding of my invention, one embodiment of will be described as applied to the separation of one or more minerals from ores in which they are found, as representative of one of the uses to which my method and apparatus may be applied, though it will be understood by those skilled in the art that the same method and the same apparatus may be employed for other uses such as theselective any material capable of flotation separation of separation and I do not desire that the following description of one specific application of my invention be considered as limiting either the method orthe apparatus to the specific use described. In thepresent practice -of flotation separation of minerals from ores in which they are found, it is the common practice to grind the ores to a predetermined degree of fineness, depending upon the character of the ore and to add thereto selective reagents and sufficient water to produce a pulp of a predetermined consistency upon the character of'the ore.

' large Fig. 2 illustrating a modified form of pan which formed is then passed to flotation cells in which the pulp is agitated and air is blown into the pulp to cause air bubbles to attach themselves to the selected minerals or mineral compounds causing them to become sufiiciently buoyant to rise. to the top of the pulp where they may be passed off or skimmed ofi from the remainder of the pulp. My method and apparatus constitutes a substitute for the flotation cells andflotation methods now commonly practised, which will avoid the necessity for the expenditure of the quantities of power now required for the operation of such flotation methods and apparatus and to provide a. more rapid process by which the selected materials may be separated from the remainder of the materials in the mixture- Referring to the drawings, I have illustrated in Figs. 1 and 2, one form of apparatus which may be employedin carrying out my invention, as comprising a relatively shallow rectangular pan I which may be constructed of any suitable material and preferably has a length somewhat in excess of its width, the floor 2 of the pan presenting a substantially plane upper surface over which a stream of pulp of the character described may pass. One end 3 of the pan may be considered as the entrance end into which end the pulp may be introduced in a substantially continuous stream, the end wall of the pan preferably sloping upwardly and rearwardly as indicated in Fig. 2 to provide an angular shelf upon which the stream of material may pour. The pan is divided longitudinally by means of a plurality of partition strips 4 which extend from the upper surface of the floor 2 of the pan to divide the pan into a plurality of elongated passageways 5, 6, I and 8 extending substantially the full length of the pan, the partition strips 4. being constructed of any suitable material such as wood, while similar strips 9 and Ill may be employed adjacent the opposite side walls H and [2 respectively to provide surfaces upon which a sheet of screen material l3 may be supported, cross-bars or strips l4 and I5 being preferably provided extending laterally' across each end of the pan to support the end edges of the screen sheet l3. While the height of the strips 1, 9, ill, I4 and I5 may be varied when the apparatus is to be applied to the treatment of different materials or different kinds of pulp, a typical application of my apparatus for the separation of certain minerals from their ores appears to require a spacing of the screen sheet l3 from the upper surface of the floor 2 of the pan of about 2 inches.

A baflle or protector plate l6 may be provided at the entrance end 3 of the pan extending across the upper surface of the screen sheet [3 to prevent undue abrasion of the screen sheet B by the incomingstream of pulp material. 7

The pan, with its screen sheet assembled as hereinbefore described, may be suspended by any suitable means and in any suitable manner, though I prefer to mount the apparatus in such manner that the floor 2 of the pan extends in a plane disposed at an angle to the horizontal, as is illustrated particularly in Fig. 2, to insure a gravity flow of the stream of pulp material downwardly along the surface of the pan from the entrance end 3 toward an exit 25. The pan I is alsopreferably mounted in such manner as will permit its being vibrated or shaken in much Y I9a engaging eccentrics I82) and I9b secured to and rotatable by a pair of shafts 20 and 2I which are in turn mounted upon a base-frame 22 so.

that upon rotation of the shafts 20 and 2|, the entire pan I wil be moved through a circular motion to cause any material upon the surface of.

the pan to be agitated, vibrated or shaken, the

degree of violence thereof being controlled by the selection of the eccentrics I81; and I9b and the speed of rotation of the shafts 20 and 2|. If desired, the motion of the pan I may be accelerated during different portions of the cycle of rotation of the eccentrics by means of tension rods, springs or other similar devices 23 and 24v engaging the eccentric brackets I8 and I9 in the manner shown and described in-the copending application Serial No. 146,717, filed June 7, 1937, by John A. Traylor and John B. Traylor.

With the apparatus constructed as hereinbefore described, it will be apparent that the pulp introduced into the entrance end of the pan I will flow downwardly along the surface 2 of the pan in a relatively shallow stream. The screen cloth I3 should be selected of such mesh as will allow all of the materials in the pulp to readily pass therethrough so that upon the agitation of the pan, the entire sheet of pulp material passing over the pan will be thrown upwardly against the under surface of the screen I3 and through the meshes of the screen. As will be understood by those skilled in the art, the repeated tossing of the pulp material upwardly against and through the meshes of the screen I3 will cause the pulp material to be splashed or sprayed through the screen material and upon falling back through the screen I3, air will be entrapped in the pulp material in finely divided form, thus causing the pulp material to become self-aerated without the necessity of introducing air into the pulp by other artificial means. The air so introduced will cause a froth to form upon the stream of pulp, which being buoyant, will tend to remain upon the upper surface of the screen sheet I3, while the repeated tossing of the liquid material upwardly through the meshes of the screen I3 will washthis froth downwardly over the surface of the screen I3 toward the open end 25 of the pan at the lower end thereof. This froth, bearing the separated minerals or mineral compounds desired, may then be taken from the exit 25 and carried through any other process indicated as desirable for the recovery of the desired minerals. At the same time, the remaining pulp material or tailings will pass outwardly through the spout II, which as is illustrated in Figs. 1 and 2; communicates with an opening 26 extending across the lower end of the pan, these tailings being either recirculated through the pan or passed to another pan where, by the employment of other reagents or a diiferent degree of agitation, other minerals oi materials may be separated therefrom.

It will-therefore be observed that I have provided a method of flotation separation of selected materials from a mixture of different kinds or characters of materials by rapidly flowing a thin stream of pulp containing the mixture of materials and by agitating and tossing this stream of material into the air, it becomes self-aerated, providing a ready and economical means for separating the froth from the remainder of the pulp. As will be understood by those skilled in the art, the amount of power which will be required to violently agitate a thin sheet or stream of the pulp material by the method and with the ap- 3 paratus hereinbefore described; will be relatively small as compared with the amount of power required to agitate a large mass of this material as is now required in known methods of flotation separation. a

In order to provide for additional whipping or beating of the pulp material during its passing downwardly across the surface of the pan, I prefer to provide relativelyv shallow obstructions 21 along the surface of the pan such as illustrated in Figs. 1 and 2, as comprisingstrips of halfround iron, steel or similar material extending laterally across the surface of the pan I, these obstructions being spaced from each other in the direction of the flow of material across the surface of the pan. Thus, as the stream of'pulp material passes downwardly over the surface of the pan and encounters one of the obstructions, a riilie is caused in the stream tending to throw the material upwardly against the screen sheet I 3 and thereby causing Splashing or tossing of the .pulp material through the screen sheet I3 in aridition to thatcaused by the agitation of the pan As is illustratedparticularly in Fig. 3, additional heaters or whippers may be employed to further cause the material to be whipped, beaten or tossed and to assist in the self-aeration of the pulp material by further breaking up the globules of air which are entrapped in the pulp material due to its agitation and due to its passage through the screen sheet I3. .These additional heaters are illustrated in Fig. 3 as comprising relatively narrow strips of screen material 28 extending laterally across the pan I,'each of the strips of screen material 28 having a length somewhat less than the width of the elongated passageways 5, 6, I and 8, one edge of each of the strips 28 being secured to the upper surface of the door into the pulp stream as it passes over the pan, Iv

may employ a pan of the character illustrated in Figs. 4 and 5, wherein the bottom 2a of the pan I is formed of a series of overlapping strips of sheet material 29 arranged in the form of louvres, the forward ends 29a of all or selected ones of the strips-being, if desired, turned upwardly to provide an obstruction for producing riflies in much the same manner as thepbstructions 21 described with reference to Figs. 1,. 2 and 3, while the rearward edges 29b of each of the strips extend rearwardly below the forward edges ofthe preceding strips a suiiicient distance to prevent the exit of the pulp through the openings 30 between the adjacent strips as long as the stream of pulp continues to descend over the surface of the pan I.

In this form of the device, a screen sheet I 3 may be employed disposed above the floor 2a of the pan in the same manner as described with reference to Figs. 1, 2 and 3, and the passage of the material downwardly over the surface of the pan combined with the agitation of the pan and the employment of the upturned ends 29a of each of the louvre strips will cause the pulp mawill be whipped upwardly and.

terial to be thrown upwardly against and through the screen sheet .I3 to produce the sel -aeration as described with reference to Figs. 1, 2 and 3. However, upon the tossing of the material upwardly from the floor of the pan, airwill be drawn inwardly through the openings 30 between the adjacent strips 29, which air will become entrapped in the descending pulp material to furthe]: assist in the aeration of the material and in the production of the froth by which the selected materials or minerals are to be removed from the pulp.

In this form of the device employing the strips 29 and openings 30 therein, I prefer to provide a sub-bottom 3| for the pan I, extending below the floor 2a of the pan so that in the event the flow of the material over the floor of the pan is interrupted for any reason as by the clogging of the space between the floor 2a and the screen sheet I3, any liquid material which is backed up and would tend to flow backwardly through the openings 30 will be retained by the sub-bottom 3| and allowed to pass downwardly therealong to the exit spout IIa of the machine. At the lower end of the pan I, the last or lowermost of the strips 29 is provided with an opening 26a. corresponding to the opening .26 illustrated in Figs.

1, 2 and3 by which the tailings or pulp remain-.

ing after the separation of the froth therefrom may pass downwardly through the exit spou-t IIa to be disposed of as waste or to be subjected to further recovery processes as described with reference to Figs. 1, 2 and 3.

With the form of the device shown in'Fig. 4, the heaters or whippers similar to those illustrated in Fig. 3 may be employed, such beaters being illustrated in Fig. as comprising strips I of screen material 28x, the rearward edges of which are welded or otherwise secured to the underneath surface of each of the strips 29 immediately adjacent the openings 30 therebetween, so that the incoming air passing through the spaces or openings 30 will be immediately whipped or broken up to assist in its entrance into the pulp material.

In Fig. 6, I have illustrated a still further modified form of apparatus which may be employed in the practice of mymethod, this form of the device comprising the pan I, the pulp-supporting surface or floor of which is constructed of porous material indicated at .2b and preferably formed as illustrated particularly in Fig. 2 of a sheet or blanket of filter material 32 such as that commonly used in the mining industry, and preferably having a backing sheet of screen material 33 and 34 disposed upon the upper and lower surfaces of the blanket 32 to provide a load-sustaining surface through which air may readily pass. In this form of the device, the screen sheet I3 may be employed disposed in the same manner as described with reference to Figs. 1-5 and if desired, riflle forming obstructions 21 may be provided as indicated in Fig. 6. In this form of the device, however, the subbottom 3i of the pan, spaced below the loadsupporting floor 2b, provides a duct 35 extending completely below the floor 21) into which compressed air or other gases may be introduced through a suitable pipe 36, air or other suitable selected reagent gases being pumped into the duct 35 and permitted to pass upwardly through the porous floor 2b where such gases may enter the shallow stream or sheet of pulp material flowing downwardly over the floor 2b. However, it must be understood that in this form of the device also, the pan is agitated in any suitable manner as described with reference to Figs. 1-5. The downward passage of the sheet of pulp material, the tossing thereof upwardly against and through the screen sheet I3 with the additional introduction of air from the underneath surface of the sheet of pulp material will cause complete aeration of the pulp material necessary or desirable to separate the selected materials or minerals from the pulp.

While in the forms of the device hereinbefore described, the screen sheet I3 has been illustrated and described as attached directly to and movable with the pan I, it will be apparent to those skilled in the art that the pan I and the screen sheet I3 may be mounted independently of each other and one or the other moved relative to the other for the purpose of whipping the sheet of pulp material into a froth. As is illustrated in Fig. 8, the pan I may be mounted upon the base-frame 22 by means of eccentric or other drive supports in the same manner as described with reference to Figs. 1, 2 and 3, while the screen sheet I3 may be mounted upon an auxiliary frame 31 which may be constructed of angle iron or other suitable material, having extending therefrom brackets 38 attached to a suitable stationary support, for example, to a crossbar 39, opposite ends of which are secured to uprights or legs 40 extending downwardly outside of the pan I to engage and be supported by the base-frame 22 as indicated at 4|. Suitable bracing 42 may be provided, if desired, it being understood that the essential, feature of this form of the device lies in the mounting of the screen sheet It so as to remain stationary while the pan I carrying the stream or sheet of pulp material is vibrated or shaken relative to the screen sheet I3. In this form of the device, it

will be apparent that as the material is thrown upwardly from the floor 2 of the pan I, it will be tossed against the screen sheet I3 and will produce the froth by self-aeration in the same manner as was described with reference to Figs. 1, 2 and 3, while by independently mounting the screen sheet I3, it is possible to so locate the screen sheet I3 that upon each upward throw of the pan I, the surface of the stream or sheet of pulp material will be forced through the screen sheet I3 to assist in the whipping or beating of entrance end 3 of the pan, I provide an angularbafile 33 extendinglaterally across between the side Walls II and I2 of the pan, the baflie 33 having a shelf portion 44 thereon extending substantially parallel to the surface of the floor 2 of the pan I for a relatively short distance along the length of the pan. With this form of the device, the pulp material entering the space 35 between the end 3 of the pan and the bafiie 43 will pass downwardly to the surface of the floor 2 of the pan and flow therealong, the agitation of the pan and the tossing of the material either with or Without the assistance of obstructions 2i, heaters 28, causing aeration of the pulp to produce the froth thereon, floating the materials desired to be separated from the remainder.

Near the opposite end of the pan I, I may provide a plurality of Skimmers 46 preferably comprising relatively narrow strips of sheet material secured to opposed side walls II and H of the pan and extending therebetween, the strips 46 being spaced from each other longitudinally of the pan to provide vertical passageways 41- therebetween. As the pulp material with the froth thereon flows downwardly along the surface of the floor 2 of the pan, the froth material will tend to pass above the skimmers 46 while the remainder of the pulp material will tend to pass below the skimmers, thus effectively separating the froth from the remainder of the pulp material, the froth passing outwardly of the pan at the exit 25 thereof in the manner described the partitions prevent excess lateral shifting of the pulp.

with reference to Figs. 1, 2 and 3. I prefer that v the skimmers 46 be disposed in a plane extending at an angle to the surface of the pan I so that the forward edges of the strips 46 are disposed at a lower level than the rearward edges thereof, tending to force the pulp material downwardly as it engages the skimmers. Thus, any froth material which falls to pass above the skimmers 46 will flow under the ski'mmers until it reaches one of the openings 47, whereupon the froth material or buoyant particles may pass upwardly to a position above the skimmers and thus be separated from the remainder of the material.

While I have fllustrated in Figs. 1-9 one means of agitating the pan comprising the rotatable shafts and eccentrics, it will be understood by those skilled in the art that other means of agitating the pan may be employed such as the vibrating mechanism illustrated and described in United States Letters Patent 1,846,326 issued to" James A. Flint on February 23, 1932, an adaptation of this form of vibrating mechanism being illustrated in Fig. v10 herein as comprising a pan I to which a screen sheet I3 is secured upon spaced partition strips 4, 9, I ll, etc., the pan-I being mounted upon a supporting yoke structure or frame 48 which is connected by means of resilient bars 49 to a base-frame structure 50, the resilient bars being selected to have such period of vibration as will synchronize with the frequency of alternating current which is supplied to an, electromagnetic vibrating mechanism ineluding a coil 5| arranged upon a core 52 supported upon and carried by the base-frameifl and acting upon an armature core 53 secured as indicated at 54 to the yoke structure 48.

By employing the partition strips 4 dividing the pan into a plurality of relatively narrow sections, the device is particularly adapted for use on dredges or other similar locations wherein considerable movement of the boat, dredge or other device upon which the apparatus is mounted would prevent the employment of other types of flotation apparatus. The partition strips will tend to confine the'pulp material to its plurality of passages across the floor of the pan though if desired openings 60 may be provided through the partitions to permit a slight cross flow of the pulp material to equalize-the loading of the pan while splashing or From the foregoing description, it will be apparent that I have provided a flotation separation method and apparatus which is extremely simple in character and economical to construct and operate, the pulp from which the selected materials are to be separated being spread out in a relatively thin layer so that the entire layer of pulp material may be so tossed, splashed or agitated as to beat or whip air into the pulp mixwhich froth may be readily removed'from the remainder of the pulp material.

It will also be observed that I have provided a relatively simple, and inexpensive mechanism for carrying out such process, the only essential structure acquired being that of providing a supporting surface or surfaces over which a thin layer or sheet of material may flow andso vibrating and agitating the stream of material as itpasses over the pan as to produce the aerated froth thereon. I Many uses for the method and apparatus disclosed herein will present themselves to those skilled in the art, such as the washing of 'coal to separate dirt or other debris from the coal, the washing or classifying of ores, the separation of a multiplicity of minerals from ores or earth and the separation from a mixture of minerals certain selected ones of the minerals by subsequent treatment of the mixture of the minerals by my process and with my apparatus.

While I have shown and described the preferred embodiment of my invention, I do not desire to be limited to any of the details illustrated or described herein except as defined in the appended claims.

I claim:

1. In,an apparatus for flotation separation of selected materials from a pulp containing a mixture of said materials with other materials, a pan having a floor disposed in a plane such that pulp material introduced at one end of said floor will flow toward the other end of said floor, a screen disposed in spaced relation above the floor of said pan, means for imparting an endwise vibratory motion to said pan and said screen,

said pan in a direction substantially crosswise of the direction of said vibratory motion to cause the stream of pulp material flowing across said floor to be repeatedly passed through said screen to whip air into' said stream of material.

2. In an apparatus for flotation separation of selected materials from a pulp containing a mixture of said materials with other materials, a shallow pan having a floor disposed in a plane such that pulp material introduced into one end of said pan will flow toward the other end of said pan, a screen extending above said floor and spaced therefrom by a distance in excess of the depth of the stream of pulp material flowing across said floor, means for imparting an endobstruction means extending across the floor of wise vibratory motion to said pan, obstruction means extending across the floor of said panin .a direction substantially crosswise of the direc tion of said vibratory motion to repeatedly toss said pulp material against and through said of said pan will flow toward the other end of said pan, a screen extending above said floor and spaced therefrom by a distance in excessto the depth of the stream of pulp material flowing across said floor, means for imparting an endwise vibratory motion to said pan, obstruction means extending across the floor of said pan in a direction substantially crosswise oi the direction of said vibratory motion to repeatedly toss said pulp material against and through said screen to whip air into said pulp material, an exit for the-froth produced upon said stream of material communicating with the upper sur-,

face of said screen and an exit for the remainder of said pulp material communicating with said pan at the level of the floor of said pan.

4. In an apparatus for flotation separation of selected materials from a pulp containing a mixture of said materials with other materials, a relatively shallow pan having a floor disposed in a plane *such that pulp material introduced at one end of said floor will flow in a relatively thin stream toward the opposite end of said pan, means for imparting an endwise vibratory motion to said pan, obstruction means extending across the floor of said pan in a direction substantially crosswise of the direction of said vibratory motion, aerating means suspended above said floor and said obstruction means, said ohstruction means extending above the floor and into the stream of material adapted to flow across said floor, for engaging said pulp material as it flows across said floor and tossing the same into engagement with said aerating means to whip air into said pulp material.

5. In an apparatus for flotation separation of selected materials from a pulp containing a mixture of said materials with other materials, a relatively shallow pan having a floor disposed in a plane such that pulp material introduced at one end of said floor will flow in a relatively thin stream toward the opposite end of said pan, means for imparting an endwise vibratory motion to said pan, obstruction means extending across the floor of saidpanin a direction substantially crosswise of the direction of said vibratory motion, said obstruction means comprising bars secured to the floor of said pan and projecting above said floor into the stream of material adapted to pass across said floor, and aerating means suspended "in spaced relationship above said floor whereby said steam of pulp material is engaged by said bars and repatedly tossed into engagement with said aerating means to whip air into pulp material.

6. In an apparatus for. flotation separation of selected materials from a pulp containing a mixture of said materials with other materials, a pan having a floor disposed .in a plane such that materials introduced into one end of said pan will flow toward the opposite end of said pan, means for imparting an endwise vibratory motion to said pan, and whipping means secured to the floor of said pan and adapted to be vibrated relative to the floor of said .pan by said motion of said pan and extending within the stream of material flowing across said pan for whipping air into said stream of material.

7. In an apparatus for flotation separation of selected materials from a pulp containing a mixture of said materials with other materials, a panhaving a floor disposed in a plane such that materials introduced into one end of said panwill flow toward the opposite end of said pan, means for imparting an endwise vibratory motion to said pan, and means for whipping the pulp material as it passes over the floor of said pan, comprising strips of perforated material extending across the floor of said pan in a direction substantially crosswise of the direction of said vibratory. motion, one edge of said strip material being secured to the floor of said pan, the other edge of said strip material being free to vibrate within the stream of material in response to said vibratory motion and whip air into the stream of pulp material.

JOHN A. TRAYLOR.

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