US2312665A

US2312665A - Screening apparatus

Info

Publication number: US2312665A
Application number: US358983A
Authority: US
Inventors: Edward B Moore
Original assignee: Individual
Current assignee: Individual
Priority date: 1940-09-30
Filing date: 1940-09-30
Publication date: 1943-03-02
Anticipated expiration: 1960-03-02

Description

'Mmh 2,1943. vBE /OWE 2,312,665

SCREENING APPARATUS Filed Se pt. so, 1940 Patented Mar. 2, 1943 w S WG WWW? Z 1 dpplication september at, 1940; sem1 No; 358,983,;

apparatus; it

My invention relates to screening more particularly to'apparatus foruseparatlnfl fronia continuously progressedrnass of p'articueg late material particles ofundesirable sizes shapes, and my invention has for.1an;objec t the V this character.

provision of efiicient and. reiiable apparatusioi Although apparatus en bodying invention is not limited thereto,'it"is particularly usefulin separating particlesof slate or other unde sirable'substances from a' I'naSs'of coal. it ls common practice, in preparing various ,types: of coal for marketingwtoscreen the 'material: to t size-so as to provide substantially uniform grades of coal, each'grade representing particles of such' size as to pass through a selected screenhaving.

openings of the desired manimun size andffto be retained ,on a 'second screen having openings of V the desired minimum size.i' Although such screening operations are relatively efficient" ingradingthefcoal, it is well known that underx sized particles of coal may remainineachgrade due to theiact that it 1s uneconomical to carry the screening ope'rationi beyondsa 2 certain pointy 5 w and it is likewise ;well.known .that the various grades of coal, particularly whenfminedin'cer-I tain localities, will also contain afllarge number of pieces of relatively noncombustible material such as slate or thelik e. These fpieces oi slate are usually relatively flat as compared to' the substantially cubical fracture of the'coal." r The presence ofthese'so-called hats in themass of coal is highly objectionable to thepun chaser, andiattempts have heretofore been'made to provide economical methods of removing such.-

flats. So far as I am awareghowever, '1 all such I1 "attempts have been relatively unsuccessfuland something is e f Ob desired n apparatus'oi flats-contained therein.-

I l In carrying out my invention in one form,

N f 331L 55,

shelves the shelves. being-arranged step-like relation The rnaterlal to be vsclrfe'e:tied;is tibplled wt th u e v r n t he.ser ines e, m means are fprovided for imparting thereto recurrent swoon which causesthe niajtrial tq'pas from sheli to shelf downwardly ofithe screening 7 element" The recurrent amotion imparted @to the screening element iincludesa horizontal" reciproreating component' characterized; b h 7 changes inrthe speedof'rnovement t atthepap ticles, which momentarily scolnetq rest onftlje 1" shelves and. which .are ucharacterizedfby a dimer 'sion smallerflthanithe' width or height of the slots, will be discharged through the s1ots;4tne*move- 'ment caused byth e inertia of the particles.

Thus flats, which momentarily .rest on-the shelves 2.;

in fiatwise relation, are separated from the mass of coal-and those flats whilchnos not occupy such a position on3the. shelvespass downward Qto the, next shelf .where they J again; have] an 10 tion for" dischargel t I-Qfi hf the isljots. s 'j' fFor a more co' nplete understanding ofmy-invention;reference should' now be had to the d awin intvhichz I Fig, l 'isatop plan vie of bodying my invention;

a ap a us: am-

' Fig. 2 is an=elevational-vie 5 oi-theapparatus shown in Big; lzgan'd' 3 a -fimfi et i taEi m ts iolifi view: showing a .p'ortion oi the creening element. and illustrating; the manner in which the n flats are caused topa'ss through the'slots'fsjyfas- 'ovin'g mass of to separate the flats from the. .coal; v

ically; =.extend1n cross beam"Mis -Suitable diagonlzblaces 7 o be. provided for the" 'upright members provide a' screening apparatustowhich tnematerial to be screened mayQ-be continuously d elivered. and from which' thef material, I after screening, is continuously dischargdywhich" ap paratus comprises any inclined screening-'- elevme'nt having a plurality of transversely extend-- ing shelves with slots of predetermined size extending'along the rear edges of theshelves. "In the preferredembodi'ment of. my invention these slots constitute the spaces between adjacent supported on the base l0; icomprises. *which-includes-apair:of1;sideimembers connected together ;at-a'thelr.-;opposite nds byJ-s:

sho

i Z the screening 1 element; which is movably cross members I 5: and; 16- r esp,e :tively..- Extend-V ing transversely-of the .frame iormed abyilthe N15,, and I [6,; Ifprovide 'a'f'pl uch abrupt V 'the d!&W1ng',TI1191173751 0 "my-invention as embodied in. a screening appa- :ratus. comprisinga; base; 1' ',adjacentone end with wirame comprising; a pair or enmarsupaag Li I V v connected together. at their I uppefl fend b "1a the: preferred embodiment of my gnvmion ing supporting frame.

between, each shelf being spaced forwardly of the one immediately above to provide a stepconveyor (not shown) or other receiving means.

As shown best in Fig. 2, the upper end of the screening element or frame is supported at each side on an adjustable hanger 2i, the'lower end of each of the hangers 2| being pivotally connected to a bracket 22 on the portion I6 of the screening element and the upper end of each hanger being pivotally connected to a bracket 24 secured to the cross bar [2 of the upstand- The screening element is thus supported in an inclined position but is free to move in a substantially horizontal direction relative to the base l0.

While any suitable mechanism may be provided for imparting to the screening element a recurrent motion of the character to be hereinafter described, I have shown for purposes of illustration a mechanism which comprises a pair of springs 25 disposed on opposite sides of the screening element and having their'respective opposite ends connected to the base and to the members ll of the screening element. The operating mechanism also includes an operating bar which, as shown, is pivotally connected at one end to the cross member and is provided at its opposite end with a lug or cam follower 21 and adapted to be engaged by-a rotatable cam 23 carriedon a, shaft 29, the shaft 29 being rotatably iournalled in brackets 30 which extend rearwardly from the upright supporting members i I. In order to maintain the operating bar 26 and the follower 21 in contact with the surface of the cam 28 at all times, suitable biasing means may be provided for the-bar 26, and for purposes of illustration I have shown a coil spring 40 associated with the pivotalconnection between thebar 2B and the cam member l5 for urging the bar 26 downwardly toward the cam.- The shaft 28 isadapted to be driven'by any suitable powermeans (not shown) in a counterclockwise direction, as indicated by the arrow in Fig. 2,

and the cam 28 is shaped to provide a gradually increasing radius terminating in an abrupt shoulder 3|. 1

' In the operation of the apparatus thus far described, coal or other suitable particulate material to be screened may be continuously fed to the upper end of the screening element in any desired manner, and for purposes of illustration I have shown a hopper 32 supported on theupright frame formed by. the members H and [2. The coal issuingfrom-the lower end of a hopper 32 engages the flat end piece i6 of the screening element and moves downwardly onto the uppermost ones of the step-like shelves I1. If it is assumed now that the shaft 29 is being rotated in the direction indicated, itwill .be apparent that the'cam 28 will act on the cam follower 21 to move the operating rod 26 in a left-hand direction, whereupon the screening element moves in a corresponding direction, the upper end Hare spaced vertically to provide slots i8 thereswinging on the hangers 2| and the lower end sliding along the base 10. The sliding movement of the lower end is of course guided by the track 19 in which the screening element rests.

In Fig. 3 I have shown the relationship which the particles of coal and the flats may assume with respect to the shelf members I! as the mass of coal passes down the inclined screening element. As there'shown, certain of -the flats 33 will assume a flatwise position on the shelves l1, although others of the flats, for example the one indicated by the reference numeral 34, may be carried along with the particles of coal. As soon as the cam 28 is rotated to a position wherein the cam follower 2'! passes over the abrupt shoulder 3!, the springs 25, having been extended during the movement of the screening element in a left-hand direction, will abruptly move the screening element at a high speed in a right-hand direction. The abrupt initiation of this high speed movement will cause the flats 33 (Fig. 3), by reason of their inertia, to be discharged through the slots I8 at the rear edges of the shelves II. The track IS in which the lower end of the screening element is guided is provided at each side with inwardly extending portions 35 which are positioned to be engaged by theends of the side members l4 and constitute stops for the screening element which abruptly terminate the high speed movement of the screening ele-' ment under the force exerted by the springs 25. This abrupt termination of the high speed movement causes the particles of coal 36 (Fig. 3) and those flats which have not been discharged through the slots l8, for example the flat 34, to move downwardly over the shelves and it will be apparent that at .each such movement the flats remaining in the mass of coal will be given an additional opportunity to assume a flatwise position on one of' the shelves l1, so that by the time. the mass of coal reaches the lower end of the screening element substantially all of the flats will have been removed. In addition to the flats,

it will of course be apparent that any particles of coal having a dimension smaller than the height of the siots l8 will likewise be separated from lustrated in the drawing is adaptedto provide a recurrent motion characterized by an abruptly initiated and abruptly terminated high speed movement, the abrupt initiation causing movement of the flats through the slots and the abrupt termination causing progressive movement of the mass of coal down the inclined screen, it will be apparent that various other sequences of movement may be employed solong as the movement of the screen is a recurrent movement characterized by sufficiently abrupt speed changes to effect the desired movement of the particles with respect to the shelves l1.

Although the shelves ll may be of various widths and, if desired, may be, arranged in exactly horizontal relation, I have found that excellent results are obtained if the width of the shelves is only slightly greater than the topsize of the graded coalto be treated. Furthermore,

Y I have found that movement of the'flats through the. spaces or slots between the shelves l'I will be facilitated by arranging the shelves ll with a slight rearward inclination from the; horizontal, and in Fig. 3 I have shown the shelves as inclined from the horizontal by a small angle a. If desired, the shelves I1 may be so supported at their opposite ends on the side members l4 as to provide for angular adjustment of the shelves to, vary the angle a if it is desired to changethe rearward inclination of the shelves. Such adju'stment of the shelves I! will of course alter the size of the slots I8, and in some cases it may be desirable to change the inclination of the shelves without changing the size of the 510125.

This may be accomplished by adjusting the hangers 2|, each of which is provided as shown with a turnbuckle 23 which may be rotatedto lengthen or shorten the hangers 2| as desired; It. may also be desirable, upon adjustment of the hangers 2], to raise or lower correspondingly the hopper 32 and any suitable means (not shown) may be provided for this purpose.

It will thus be seen that I have provided an apparatus which is of exceedingly simple construction, involving only a few parts, and which is effective in its operation to remove substantially all of the flats from a continuously progressed body of coal during passage of the coal over a screening element having a predetermined recurrent motion.

While I have shown particular embodiments of my invention, it will be understood, of course, that I do not wish to be limited thereto since many modifications may be made, and I, therefore. contemplate by the appended claims to cover any such modifications as fall within the true spirit and scope of my invention.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. In a screening apparatus, the combination of a screening element across which the material to be screened passes during the screening opera:

edges thereof and by an abrupt termination of said high speed forward movement to cause other portions of said material to be discharged from the front edge of each shelf member so as to be advanced down said steps.

2. In a screening apparatus, the combination of an inclined screening element over which the material to be screened passes during the screening operation, said screening element including a plurality of vertically spaced shelf members each of which is of a width substantially equal to the maximum graded size of the material to be, screened and is positioned forwardly of the one above to provide a series of steps having discharge slots therebetween of a height less than the minimum graded size of said material, means for supplying a mass of the material to be screened to the upper portion of saidscreening element, and means for producing a recurrent motion of said screening element, said motion producing means including means for abruptly initiating a high speed forward movement whereby pieces" of saidmaterial on said shelf members having at least one dimension smaller than-thewidth of said discharge slots are discharged throughsaid slots,and means for abruptly terminating saidhigh speed movement whereby the remaining material on said shelf members is discharged from the forwardedge of each shelf progressivelyto move said material down said series of steps.

3'. In a screening apparatus, the

edge of each shelf causing progressive movement of said material across saidscreening element from shelf to shelf, and means for imparting to said screening element arecurrent motiOn in-,. eluding a horizontal component characterized by abruptly initiatedhigh speed forward .move-.

ments to cause rearward discharge of some :of,

said material throughsaid slots-and by abrupt termination of said high speedforward move ments todischarge some of said material from the forward edges of said shelves whereby said material-advances forwardly down said screening element and is discharged forwardly therefrom.

4. In a screening apparatus, the combination of an inclined frame, a'plurality of substantially flat shelves extending transversely of said frame each shelf being of a width substantially equal to the maximum graded size of the material to be screened, said shelves being inclined rearwardly at a small angle from the horizontal and spaced to provide unobstructed openings of predetermined width between said shelves, means for causing a mass of particulate material to pass progressively down said inclined frame from shelf to shelf whereby discrete particles of said mass momentarily rest on said shelvesfand means for abruptly moving said frame to cause some of the particles on said shelves to pass through the spaces between said shelves.

5. In a screening apparatus, a. screening element comprising an inclined frame having a plurality of flat shelves of a width substantially equal to the maximum graded size of the material to be screened extending transversely thereof and having unobstructed slots of fixed predeter mined height extending along the rear edge of each shelf, means for causing a mass of particulate material-to pass progressively downwardly over said screening element from shelf to shelf whereby discrete particles of said mass come to rest momentarily on said shelves, and means for abruptly. moving said frame forwardly at recurrent intervals whereby the inertia of said particles causes certain of said particles to be disthereacross in step-like relation, said shelves combination; of an inclined screening element having a p1,u-,-. rality of substantially flat shelveson whichthe material to be screened may momentarily rest, during passage over said screening element, said screening element having'slotsofflxed predeter-j; minedwidth adjacent the rear edge of each being spaced apart vertically to provide unobstructed openings oi sumcient size to permit the passage of undersized pieces of coal and the edgewise passage of flats therethrough but insuf- ,ilcientto permit the passage of the remainder of said mass of coal, each of said shelves :being 'oi the'mass on each shelf onto the shelf below whereby said mass passes progressively down said 7' inclinedzscreening element from shelf to shelf for discharge forwardly therefromand additional-flatsand under-sized pieces or coalcon- 'tainedtherein may come to rest momentarily on succeeding shelves for discharge rearwardly through said openings. m

1 7. An apparatus Iorseparating flats and under-sized pieces or .coal from I an otherwise graded-tq-size mass of coal comprising an inclined screening element including a plurality r substantially horizontally disposed step members of a width substantially equal to the maximum graded size of the material being treated,

said step members being vertically spaced apart to provide open slots therebetween of a predetermined height less than the minimum graded size of the material being treated, and means for imparting to said screening element a re curring vmotion including an abruptly initiated and abruptly terminated, high speed, horizontal component 8. An apparatus for separating flats and under-si'zed pieces of coal from an otherwise graded-to-size mass of coal comprising a screen ing element including a plurality of step members, each 0! said step members being of a width suflicient tosupport only one row of particles of the maximum graded size and being spaced apart vertically from the adjacent step members to provide unobstructed, slots therebetween of a height less than the minimum graded size or the material being treated, means for causing a mass of particulated material to pass progressively downwardly over said screening element from step to step whereby discrete particles of said mass come to rest momentarily on said steps, and means for abruptly moving said screening element forwardly at recurring intervals whereby the inertia of said particles causes those having at least one dimension smaller than the minimum graded size to be discharged from said steps through said slots.

EDWARD B. MOORE.