US1135304A - Separator. - Google Patents

Description

W; K. LIGGETT & W. J. ARMSTRONG.

SEPARATOR. APPLICATION man OCT. 4. 1909.

Patented. Apr. 13", 1915.

3 SHEETS-SHEET 1.

WL K; LIGGETT & W. J. ARMSTRONG.

- SEPARATOR. APPLICATION FILED on. 4. 1909.

.' Patented Apr. 13,1915,

3 BHEETS BEE-ET 2.

fig 9,

w-Lineage 5:

W. K. illGGETT & W. J. ARMSTRONG.

SEPARATOR.

APPLICATION FILED OCT. 4. 1909.

Patented Apr. 13, 1915.

MW5MU% awzxggmfozs a SHEETS-SHEET a.

13% two-sow iarrnn I s'ra rns PATENT marten.

WILLIAM K. LIGGETT AND WALTER J. ARMSTRONG 0F COLUMBUS, OHIO, ASSIGNORS TO THE JEFFREY MANUFACTURING COMPANY, A CORPORATION OF OHIO.

. snranaron;

lowing is a specification, reference being had therein to the accompanying drawing.

This invention relates to machines forseparating partly ground material.

In reducing. ores'and similar material to a very fine product by any-attrition or im pact machine, it has heretofore been the usual. practice to keep such material in the machine until the Whole of it was fine enough for the purpose required. This process is carried on with a meat loss in both the horsepower eXpende and in the amount of finished product obtained, be-

cause all those particles already fine enough must be kept in the machine, along with the coarse, until the whole is sufficiently re duced. As an example of this sort of re duction, a tube mill grinding cement clinker may be cited. A slightly inclined, revolubletube is partly filled with small, hard, rounded stones. The partly ground cement is fed in at the high: end of the tube and is gradually worked along until .it overflows at the low end, the mass of moving stones, in the meanwhile, reducing the particles to smaller dimensions. If the material discharged from such a mill is not fine enough, the feed is reduced, or in other words, it is left in the mill longer; and vice versa, if the material is finer than desired the feed is increased.

In grinding coals, limestones, and other friable ores, with impact machines, thefineness has been produced by using fine mesh screens and keeping the material in the pulverizer until it all passes through the small meshes. On such machines the speed or intensity of the blow may be made to largely regulate the fineness of the product. A large percentage of the material will be found small enough after the first blow of the hammer. It is, therefore, better practice to use coarse screens, pass the material once through the mill, separate that which employed, such as shaking or Patentedhpr. 13, 19315.

application-filereetobera,1909. Seria1Noa520,839.

is fine enough from that which is too coarse, and pass the latter through the machine again for regrinding. To obtain this separation, many schemes have heretofore been revolving screens of various forms, but they were all more or less unsatisfactory for very small sized or damp or sticky material, both by reason of the small capacity and also on account ofthe tendency to plug the screens.

The object'of this invention, therefore, is to provide an apparatus by means of which the fine'matcrial may be rapidly and efficiently separated from the material which is coarser and must be reground.

In'the drawings Figure 1 is a side elevation. Fig. 2 is a plan view. Fig. 3 is a lefthand end view. Fig. lis'a right-hand end view. Fig. 5 is a crosssectional view look ing in the direction of Fig. 4:. Fig. 6 is a detail view of the feeding device. Fig. 7 is an enlarged cross-sectional view of one of the screening elements. Fig. 8 is a detail view of one end of the screen. Fig. 9 is a detail View showing one end of a modified form of screen.

Referring to the drawings 1 represents a casing, preferably formed of sheet metal. ,This casing is entirely inclosed except-for the various apertures hereafter to be described. It is supported and reinforced by the framework 2, which may be of any suitable design, and preferably formed of structural rolled steel.

3 is a feed hopper in which the material to be separated is delivered, preferably through a chute such as is indicated: by 4 in F ig: 5. This feed hopper is provided with a bottom comprising thb two slides 5 which may be adjusted to regulate the aperture through which material is fed to the mathe upper edge of the side plate will permil; material to overflow the side platethroughout the length of the conveyer. In

order that this overflow may be properly regulated and evenly distributed, we make the side plates adjustable. The means which we prefer for adjusting them is shownin Fig. 6. To each end of each side plate is attached a'stud 10 which extends upward through suitable apertures in the casing. These apertures in the casing are made somewhat larger than thestuds in order that the latter may have perfect freedom of movement. Each of the studs is engaged 'near its upper end by a threaded hand-wheel 11. By turning the hand-wheels 11 it will be seen that the side plates may be raised or lowered and the inclination of their top edges adjusted to give a uniform discharge of the material along the whole length of the conveyers.

Immediately below the feeding device, above described, is located the screen which .is indicated as a whole by 12. This screen is pivotally mounted at 13 and is preferably made up of a pzlurality. of separate screening elements. ach of these screening-elements comprises preferably'a receiving plate 14 of sheet metal or othersuitable material and a wovenwire screen 15. Each of the screens 15 is made, tangent to its receiving plate 14 at the upper end, and at its lower end curves slightly upward. In the drawings we have shown three of these screening elements, one located above the other, but it will be understood that any desired number may be used.

In some machinesfor'certain classes of work, it may be found desirable to considerably modify the construction of the screening elements, as above set forth. For instance, the screen may consist merely of a series of horizontal bars or of wires under tension, as shown in Fig. 9. The screen, as a whole, is made adjustable so that the angle of inclination may be varied. The mechanism which we prefer for effecting this adjustment is the crank and pitman construction shownin Fig. 5. The pitman 16 forms a connection between the screen and the crank 17. This crank is secured to the shaft 18 which is mounted in suitable bearings in the casing wall and at its outer end-carries'th I worm wheel 19. The worm 20 is suita y mounted to engage the worm-wheel 19 and may beturned by means of the hand-wheel 21. It will be readily understood that-any movement of the hand-wheel 21 will change the position of the screen. The worm and wheel connectionmakes this ad1ustment self-locking and 'no' amount of load on the screen can-possibl affect its 'position.

In the bottom to casing 1 are formedtwo conveyer troughs Q'Zand 23, in which 0 erate the two. helicoid conveyers 24: an 25 which are connected together by the gear wheels 26 and 27 and are driven by the sprocket wheel .28. Itwill be noted that i the two conveyers turn in opposite'directions and will, therefore, convey material in opposite directions. The conveyer 24 receives the material which does not pass through the screen and conveys it to one end of the machine, discharging it through the pipe 29. The conveyer 25 receives the finely divided material which passes through the screen and conveys it to the discharge pipe 30' at the opposite end of the machine from. the pipe 29.

Between the two conveyers we prefer to place a deflecting plate 31, which is ypivoted at its lower end. This deflecting plate may be moved by means of the lever 32 and may be locked in position by the clamping screw 33 which engages the segment 34:. When properly, ad usted, this deflecting plate serves toseparate the 'fine from the coarse material with a greater degree of certainty than would otherwise be possible. The degree of finenessor coarseness of the separated material'may also'be regulated, within certain narrow limits, by means of this plate. 1

At the sideof the casing, preferably on a level-with the screen, are provided a large number of small apertures 35 distributed over substantially thewhole length of the casing. These apertures all connect with the air trunk 36, which is located along the side of the casing. At the top of the casing is another groupof apertures 37, similar to the apertures 35. These all communicate with the air trunk 38.

v 39 is a fan, to the suction side of which is connected the air trunk 38 and to the discharge side of which is connected theair trunk 36. The fan is driven by means of the belt pulley 40. :Theair trunk 38 gradually increases in cross-sectional area toward the fan, the cross-sectional area at any plane having a definite ratio to the addedarea of all of. the apertures in the casing lying in front of the plane in question. This ratio is always less than one so that the velocity of air in the trunk willbe greater than that 9 through the apertures. The cross-sectional areas through they fan and at the intake end of the trunk 36 are substantially equal to that at the end of the trunk 38. -The trunk 36 is similarly shaped to the trunk 38, but

the conveyers 6-6. v ment of the side plates 9-9, the material ing is different, so that the air velocity through the apertures 35 will be greater than the velocity in the trunk 36.

4:1 .is a power shaft driven by the belt wheel 42. The shaft 41 carries the two sprocket wheels 43 and i l which drive the conveyers by means of the chains 45 and 46.

-47 is a sliding door in the casing, by means of which access may be had to 'the interior for purposes of inspection or reair. P The operation of this machine is as follows: Material is delivered to the hopper 3 through the chute 4, whence it passes to By a proper adjustis made to overflow in a'thin continuousfilm or sheet extending throughout the length of themachine. This film or sheet of mat'eriah'after leaving the feeding device, first strikes the receiving plate 14 of the upper screening element of thes'creen 12. The action of this screening element will .be best understood by a reference'to :Fig. 7. Let it be assumed-for the moment that thereisno air current passing through-the screen. It willsbe :noted that the screen is inclined at an angle, preferably more than forty-five degrees from the horizontal, and that new terial sliding down the receiving plate will acquire a considerable velocity. As the various separate particles pass the apertures in the woven screen, each of them will be deflected a certain amount. This deflection will be sufficient to permit the smaller of the :particles to pass entirely through the screen. The larger particles, on account of their larger bulk, will strike against one of the horizontal Wires of the screen and will be deflected back toward the upper side of the screen. In this way We'are-enabled to use a much'coarser and heavier screenthan would otherwise be possible. We'have, in fact, foundthat by inclining the screenat an angle of about sixty-five degrees from the horizontal-a four-mesh'may be'made as effective as a forty-mesh screen used in the ordinary substantially horizontal position. In order to make the effect of the screen uniform throughout its length, we have found it preferable to curve the lower end slightly upward. The object of this is to retard the flow of the material sothat the velocity will be substantially the same throughout. If this were not done, the velocity at the lower end would be so great that practically none of the material would pass through. In order to make sure that none of the larger particles by any chance pass entirely through the screen, we prefer to add a second and a third screening .element below the first one. IVe construct these similar to the firstscreening element,

above described, and a detailed description be regulated. This may be seen by referring again to Fig. 7. It will be noted that the amount of deflection of each particle necessary to cause it-to pass through the screening is depehdent on the angle of inclination the screen.

We have, heretofore, described the action of the screen as entirely independent ofthe air current. The air current may, in fact, be'considered' as aux1l1ary, to acertain extent, to the action of gravity in causing the deflection of the particles of material. It will be noted'that=the air passes directly across the path of the descending material and through the elements of the screen so that each particle is acted upon by the air. Viewed from another standpoint, the air current may. be considered as theprincipal agent in effecting the separation. It would betheoretically possible to merely drop the material fromjthe feeding device and subjec'tit to the air current which would defleet the finer material into the trough 23. Viewed from this standpoint, the screen may be considered as merely a baiiie or retarding device adapted to cause the material to 'p'assacross'the air current at a slower rate and thereby be more effectively acted upon. 7

As before described, the various air passages of the machineare so designed that there is no decrease in velocity from the time the air leaves the casing at the top until it enters againat the side. On this account there is no possibility of any ma terial being picked up. from the casing and deposited elsewhere. Because of the large cross-sectional area of the casing, the air velocity across it is comparatively slow and very little material will be held in suspension. Any material that is held in suspension and is carried out through the apertures 37 will be caught by the increased air currents in the trunk 38 and returned again through the fan and the trunk 36 to the casing. As before described, material after leaving the screen 12 passes either into the trough 22 or the trough 23, the two grades of material being separated by the adjustable plate 31.

It will be noted that this machine permits of a wide range of adjustments, it being possible in fact to regulate the fineness of the screened material by changing the angle of inclination of the screen, by changing the strength of the air current, or by adjusting the deflecting plate 31. An almost infinite number of combinations of adjustments-of these three elements may be obtained.

We do not desire to restrict ourselves to the exact construction herein shown and described, and it will be understood that many "changes in detail and in arrangement of partsjmay be made within the scope of our invention.

ZWh'at we claim. is I 1 ,1. Theacombinationin a separator, of-a plate inclined at anangle to the horizontal of at least 60 andadapted to. receive the materialtobe treated, a device for feeding the material in a broad uniformly thin stream to the plate along a horizontal line remote from the lower edge thereof, a ma,-

: terial 'separating screen at its upper part tangentialto the plane of the plate and at its lower part curving upward away from the saidplaneto retard the flow ofmaterial, and two receptacles below the screen one for material passing through it and the other for materialdischarged from the lower edge its lowerlpart;curving upward away from the said plane to retard the flowof' material,

asecond screen immediately below and sub- J stantial ly parallel to the first and similarly curved, and two receptacles below the screens one for material passing through themand the other fo'r material discharged from the lower edgesthereof,

.3. ,The combination n aseparator, of a .plate inclinediat an angle to the horizontal of at,least*6 0]and adapted to receive the material to be treated, av device for feeding the material in a broad uniformly thin stream to the -,plate' along a, horizontal line remote from the lower edge thereof, a ma- 1 gterial separating screen at its .upper part "tangential to the plane of the plate and at together 7 to change the" angle of inclination,

its lower part curvingi upward away from the plane to retar the flow ofmaterial, means, for Qadjusting v:the plate and I screen vand two receptacles-below the screen one for material. passing :through it and the other f ,ifor 'materialdischargedfrom the lower edge e I thereof. a

, -4; The; combination in a separator, of a plate inclined atan angle to the horizontal of at least,,60 and adapted toreceive the .rnateria'l to be treated, a device for feeding ;.ther ,materia l in abroad uniformly thin :streamto the plate along a horizontal line remote from the lower edge, thereof, a materialseparating screen at its upper part. a 1 mtangential tothe planeof the plate and-at thereof.

5. The combination in a separator, of a plate inclined at an angle to the horizontal of at least and adapted to receive the material to be treated, a device for feeding the material in a broad uniformly thin stream to the plate along a.horizontal line remote from the lower edge thereof, a material-separating screen at its upper part tangential to the plane of the plate and at its lower part curving upward away from the said plane to retard the flow of material, means for adjustingthe plate and screen together about a horizontal axisnear the line of delivery of material to the screen to change the angle of inclination, two receptacles below the screen one for material passing through it and the other for material discharged from thelower edge thereof, and a division, plate between thetwo receptacles adjustable in accordancewith the position of the loweredge of 'thescreen. I

6. 'In a separator, the combination of a feeding device, a screen arrangedto receive material from the feeding device, means for causing a current of 'air to pass downward .through the screen and across the path of rent, substantiallyfas set forth.

7. In a separator, the combination of a feeding device adapted to supply material v in a broad thin stream, a casing into which the feeding device discharges, thesaid casing having at one-side of the feeding device a plurality of air outlet apertures uniformly distributed in. a direction parallelto the breadth of the incoming stream of material, and. having onthe other side of the feeding device a plurality of air inletsuniformly distributed in a direction parallel to the terial, a closed air conduit, exterior the casing connecting the inlet and the outlet apertures, and'means for forcing air through the said conduit.

"breadth of the stream of material, an 'inclined screen positioned to receive the ma- 8. In a separator, the combination of a feedingdevice, a casing into which the mater al is' d-1scharged,flthe said casing having at one side of'the feeding device a plurality of air outlet apertures and having at the opposite'side of thefeeding device a plurality of air inlet apertures, the said outlet aper- In testimony "whereof We aflix our signa- 0 tures having an area greater than that of tures, in presence of twowitnesses. the inlet apertures, a screen positioned in the casing between the apertures and with W, K. LIGGETT. 5 its operative face directly toward the in- WALTER J. ARMSTRONG. let apertures, a closed air conduit exterior of the casing and connecting the said inlet Witnesses: and the said outlet apertures, and means for F. W. OSBORN, propelling air through the said conduit. F. A. WHiTEMAN.

Images