US1441870A - Screen - Google Patents

Description

Jan. 9, 1923.. 1,4413%].

H. A. MEGRAW.

SCREEN.

ORIGINAL FILED MAY 21, i919. 2 SHEETS-SHEET 1. 25

"1- l fi 7 g0 31 F l q H. A. IVIEGRAW.

Jan, 9, 1928..

SCREEN.

ORIGINAL FILED MAY-21.1919.

2 SHEETS-SHEET 2'.

A TTOR/l/E V HERBERT A. IJKEGI.

i h L e mik- .W, oi? New N. En.

ltppliceltieii filed ma 21,1919; eeri meeejvee. Renewed 111m a, wee. semi No. 567,196.

oity, county, and State oi? New York, have ii vei'iteti a new and useful Screen, of which the toilowlng is at speerfieetion.

p cjyhmirieal 01' tubuiai Jfhe specification presents certain impiov'emehte upon and Nlthln the invention in screens of my Patent 1,090,933 oi? March 45, 191 In that patent if disclosed e;

man-y, tubular, non-vibratory screen, suitbie pewtieuizu'ly for fine, Wet sereenh'i g, ielves on its interior and] entry and ova hi'unders exteiiiinp; 111 and out opposite ends oi the screen i and siopingg tberethrough in the general direction, one below "the other, whereby the pulp is w /posited along the bottom oi the tubular siei'een, through which the undei'size posses; once. the oversize being vented from. hdiiigzepon the fabric and beiiw cam'ied "zu'd by the eheiveeyto be deposited into ovei'eize hu'inder, where it ie carried out by it :[iow oi? Water. Jets are pieced over the topot' he eei'een to keep the screen openines the Water tl'iei efi'om passing through "iiili'l into the oversize h-u.i":.1 ie;'. Buivantages of a screen 01 this enoifeetei are boinpemtive absence of \"vehi" in mid upon the screen ,tebi'ie, freedomfrom h'loekzidiwg. waiving oi? mill. iieih'uiid convenience in em;- (1 lietiogg; the material to and. from the semen. The object in the pieeent improved eei'een ijsim'thei' to i'edUJoe weer, inure-a e eiiioieiioy, and avoid sticking of oversize particles in ti screen meshes.

in the accompanying ch-ejwins zf'st 1 is 2. view partly in side elevation and partly in ve 'tieai iotgitmiinrii section of the screen; i

W 2 is "view of the entry or dis a htuntiei' and moi-0n; 3 is a front or rhsehm eje'ei'ui eleva- Fi time; and i i Fig. 418 an elevation etthe oppoeate end, me; 2. portionln SQCtlOI]. The sieveoi screenpre er;

1.0 is of? holiow mmemd is desirably eonsti'ueted by suppoi mg the screen eioth 1i on a. frame or ekeieton s'tiuethi'e consisting of end ring}; one-ti s 172 and CORRBCiLiUQf members 13. The screen may be of various relative proportions and is here shown as of greater height than in my n'ioipatent. but

this may be varied.

tin-e oil? 3 and. CiObQti :itite lower end. aunt one it to overflow or discharge eque.

mugged iii 10111;: t flfiiil "and ad acent i m: supported on i shown prov est on gtooved robe on she-l te 'F b joui'mtiec iii Meetings 1' .eting on A3. at opposite sis of the sieve. The may be driven from o transverse eimtt 1? which. is; ermneetefl. by bevel gears 18 wit-lithe shaft 3; Whieh in turn is e01 neeted with the shei't by it sprocketeh 21in 18%; The sieve is siiqipoited eubetm'itieli y and, the pulp does; not tirmei A; which h oi'izontei,

"h'W'LSB over its bottom.

itei'ioiihy the sieve has provisions to! ntihg the hitei'ei sliding oi? the zibFeivo hie], and t'or eievetillg the ovei'sizematei'izti. 'Whieh does not pass through the meehee of he sei'eeniitgg; 1Y1@(,ii111'1. These pi'mieioiire; sheh ee o1: inward proje time" 19., which shown. emeqito the i. e lit. it The eoueii'z z 0'? these sheivee an?! 12 width oi ii{')t|l will obvious-fly "(H upon the siioeiei cond tions of ewe: but in Wei the distance i'ilezzsurel 'ifeutiziliy between them ohtiie sho'uhi he snob us to reihv-e mueh at; poseihle ti mud H L :e iihhiw' eheives; em mi hi mtmiti {My leg 0? the the gmrtiehre. The the mil ieiigrth oi the move oi so, and (or y up the huge] p 163 die Jilted the nail iengti'i o? the bottom ot the FIGVS by the entry hm i (i to H1 so npiie 1 bout it one to ion the e and pretei'ebi centrally i he hiunder i. is; from an euppiy 211 t so itehh in the lower pitched; mooiroiiiggj to the Tilt? of low Us erred and the conehieney of the mid.

zrom'lii we and matter. it tzzpeieti JOin'ijS eloiio its 1131"? E.

o, multiplicity oi? disc ope iinejeei'e assoc ed a nan'ntwi' 2?! in the iiiteiioi' of the 't'iUl 1. the t being mounted eo that they we U1 more 01 less and W1 chfieirent degrees cure the distribution desired. One such directing device is shown for each opening,

but obviously iewer could be employed.

An apron sheet 28 is secured to the under side of the entry launder, from which it porjects laterally and downwardly at the side having the openings 21. The laterally sloping, projecting part of the sheet conducts the material gently and in a thin even flow to the screen fabric at or near the bottom of the screen, and is triangular in form, being widest at the rear where the launder is furthest from the bottom, and tapering toward the lower end of the launder, in order that its discharge edgeQS may be everywhere in approximately the same proximity to the screen fabric. This apron, together with the lateral distributing outlets .21, it is to be noted, are located over the downgoing or approaching side of the valley of the screen, as determined by the direction in which the shelves face and the consequent direction of drive. This is important because the tendency of the material to flow toward the bottom of the valley coincides with the direction of screen movement, hence relative movement and wear is minimized.

A. discharge launder 28 is located above the entry launder, and likewise extends the full length of the sieve. It is inclined in the same general direction as the entry launder, but preit'erably more steeply, and conducts the oversize material out at the end opposite to that at which the entry launder leads the material in. its lower projecting portion may extend to any suitable distance or point oi discharge. At its upper end also it preterablyextends beyond the entry end of the screen, where it may be supplied with a special or additional current of water if desired, to insure the washing away of the oversize.

The launders are supported from upright frames 24:, 25 outside the ends of the screen, the connections being such as to permit the height and inclination of the launders to be readily changed in accordance with conditions. To this end the oppositely projecting portions of the oversize launder 23 are suspended by screws 80, which may be elevated or lowered by nuts 81 resting on upper portions of the said frames, through which the screws pass loosely. In like manner the rear or upper end of the entry launder 20 is suspended by a screw 32 and nut33. The lower end of this launder may rest tiltably upon a portion of the frame 25, to which it may be connected by a bolt 34, it being understood that the hole 35 in the launder through which this bolt passes is sufficiently large to permit the tilting.

In order to prevent the blockading of the screening medium by particles which are too large to pass through but large enough to become wedged in the openings, 1 provide means for supplying water to the top of the sieve, so as to wash such particles back into the discharge launder. Two water pipes 25 are provided as in my prior patent, extending longitijidinally over the top at op posite sides of the center, these pipes being perforated so us to deliver the water downward in jets oil suitable size. The wash water falls into the discharge launder and serves or assists in carrying away the oversize material.

The undersize material received in a vessel 26, which is located beneath the sim o and comes up far enough on the sides thereof to catch all the material that passes through the meshes of the screening medium. l t preferably slopes toward the discharge end of the sieve, and is provided with a discharge spout 27, which leads to any suitable point. All of the material has :i- Slll)$i3:l'l1- tially direct travel to and away from the screen. The pulp enters at one end. tho. undersize passes through the mesh of the screen and travels directly downward and 1 forward, and the oversize is elevated slightly and also continues in the same general direction.

Another cause of blocking of the screen openings, besides wedging. is the presence oi:

colloidal matter or slime upon the siliceous oversize particles. In order to wash away this slime at the moment oil. screening, in order that the oversize may be left loose upon the meshes, I now provide a spray pipo extending lengthwise within the lower part of the screen, below the entry launder, and over the screening valley. This spray means is desirably located toward the outlet side of the entry launder and beneath the apron. Its jet orifices are downwardly directed, and the streams therefrom loosen and carry away through the fabric such colloidal material as may adhere to the oversize.

What I claim as new is:

In a screen, the combination of :i horizontal cylindrical screen and means for rotating the same, a longitudinally sloping entry launder in the lower part of the screen. an oversize discharge launder in the upper part of the screen. shelves extending len thwise on the interior of the screen to limit sliding and elevate the oversize tor deposit in the discharge launder, a triangular apron cxtending laterally and downwardly from one side of the distributing launder with its longitudinal discharge edge adjacent the downgoing side 01"; the bottom valley of the screen, and downwardly-acting spray means below the entry launder at the side toward said apron.

HERBETVI A. MF 111A \V.

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