US2685968A

US2685968A - Hertrich

Info

Publication number: US2685968A
Authority: US
Publication date: 1954-08-10
Anticipated expiration: 1971-08-10

Description

Aug. 10, 1954 J HERTRICH 2,685,968

CENTRIFUGAL DISCHARGER SHOE Filed Oct. 12, 1949 3 Sheets-Sheet 1 INVENTOR. Jail-PH Hmm/cH Aug. 10, 1954 J. HERTRICH 2,685,968

CENTRIFUGAL DISCHARGER SHOE Filed Oct. 12, 1949 s Sheets-Sheet 2 7111111111. v 4 WW Y Y n I.

v INVENTOR. 5/ JJSEPH Hswm/a/ WqfW-l FITTUF/VE)5 A Aug. 10, 1954 Fild Oct. 12, 1949 J. HERTRICH CENTRIFUGAL DISCHARGER SHOE 5 Sheets-Sheet 3 INV-ENTOR.

Patented Aug. 10, 1954 CENTRIFUGAL DISCHARGER SHOE Joseph Hertrich, Hamilton, Ohio, assignor to The Western States Machine Company, Hamilton, Ohio, a corporation of Utah Application October 12, 1949, Serial No. 120,945

21 Claims.

This invention relates to new and improved shoe constructions for mechanical dischargers of the type used for removing treated solids from heavy-duty cyclical centrifugal machines.

The operation of such dischargers generally is controlled manually. The solids are held as an annular mass, sometimes a very hard one, inside a filtration screen lining the side Wall of a large basket having a centrally open top. When ready to'be discharged the basket is rotated slowly, say at 50 R. P. M., and the forward end of an elongated discharger shoe is then moved into the turning mass to cut first outward and then downward through the mass.

There are serious difficulties in the use of known discharger shoes, and particularly so when discharging very finely divided coherent solids,- such as fine grained dextrose or sugar, after treatment in high speed centrifugal machines.

The discharger shoe too frequently damages or rips out the basket lining, causing heavy expense for screen replacements as well as costly interruptions of centrifugal work. Stops generally are provided on the shoe operating mechanism to prevent movement of the shoe tip beyond the face of the screen, but stops are not always effective. Sometimes they are not set properly. Sometimes the pressure of rotating solids against the shoe produces enough elastic deflection in the mechanism to render the stops ineiiective. Sometimes the basket itself swings its screen into the shoe tip in reaction to that pressure.

A high degree of skill and care is required to minimize these troubles, yet conditions exist in the use of known shoe constructions which even the most skillful operators may not be able to control. For one thing, when the shoe is working at the basket screen the full thickness of the mass of solids may bear against it to thrust its tip toward the screen with a force that varies with the hardness of the mass, the depth of cutting of the shoe and the speed or torque of the rotating basket. Though a flexible cutting tip be used according to the Roberts U. S. Patent No. 2,076,516, the pressure of the rotating solids may still thrust it into the screen. Another factor is that the usual shoe wedges solids rotating against its face laterally inward against the resistance of inward portions of the mass, and this makes it more difiicult to control the shoe position.

Difiiculty'arises also in entering the discharger shoe into a hard mass of solids and in controlling its cutting depth as it is moved outward toward the basket screen. Though the shoe may penetrate the face of the mass, if the operator thrusts it too far in or if the basket is rotating too fast he may lose control of its position under the resulting high pressure, and damage may result. If the face of the mass strongly resists penetration by the shoe tip, the operator sometimes slams or otherwise forces it in while the basket rotates so strongly that uncontrolled outward shoe movement and damage may follow.

Occurrences of the sort mentioned not only may damage basket screens but also are liable to bend or break the discharger, and occasionally even the basket shaft or the basket itself is dam aged or wrecked.

Another practical difficulty exists in the hazard of the discharger shoe being moved inadvertently into working position while the basket is spinning at high speed, which would cause serious wreckage or injury. To avoid this dischargers are generally held entirely outside the basket on the top of its surrounding curb during spinning periods. It results that automatic discharger operation is generally avoided in the use of known shoe constructions in normal ways, because the automatic operating mechanisms which would be required for moving the shoe and controlling its movements both inside and outside the basket are too complicated for practical use.

A general object of the present invention is to provide discharger shoe constructions which overcome or largely alleviate difiiculties encountered in the use of known centrifugal discharger shoes.

A more particular object is to make the functioning of dischargers reliable and less hazardous than heretofore, so that injuries to workmen, damage to basket screens, dischargers or other machinery, and interruptions of centrifugal work may be avoided.

Another object is to make it possible to discharge centrifugals safely and efficiently without requiring a high degree of human attention and skill.

And another object is to provide discharger shoes which can be held inside the centrifugal basket at all-times without danger of wrecking the machine, so that practical automatic mechanisms may be used with safety to operate the dischargers, if desired.

According to an important feature of this invention, a discharger shoe having an elongated shoe body of suitable form is provided with two 7 cutting or digging tips at its forward end so that a double discharging action is obtained as the shoe works near the basket screen. The two tips are aligned laterally and spaced apart to act at different radial distances from the axis of the basket. The outer tip, however, is mounted for engaged and deflected by the inner tip and the face of the shoe body, which bear the main pressure of the rotating mass, while the outer tip which lies at the screen cuts out a swath of solids not thicker than the radial distance between the two tips. That distance may be selected so that only a limited pressure can be exerted by the rotating solids against the outer tip; Furthermore, the outer tip moves inward under pressure: exceeding: the force above? mentioned, thus protecting. the basket screen against injury; .and it can be arranged so that pressure from. the thin layer of solids it displaces: will not thrustit into the. screen.

In. a preferred embodiment, the inner tip'is theleading edge of the shoe body" and the. outer tip carried on an arm pivoted to the forward end of the shoe body and extending backward and: outward from it at. its. outer side, the. arm being normally held in outer position by a spring supported on the shoe body- In another embodiment the outer tip is. located on a pivotal arm at the leading end of the shoe body so. as? to extend forward and outward from. that. end and deflecthsolids' over. the shoeface, while: the inner tip is spaced ahead of the outer tip on a rigid forward extension of the shoe body.

According to another feature of theinvention, it has been found that the depth. of action of a. discharger shoe in a. rotating mass of solids can be controlled mechanically at the shoe itself by providing the shoe body with an. outwardly facingsk-id' surface to ride on partof the rotating mass at a certain distance inward from the outermost cutting edge of the shoe. When the depth of the swath being out by that edge tends to exceed the radial distance between it and the skid surface, pressure of the rotating solids against that surface holds the shoe against further movement into the" mass. or even ejects-it from too deep a: position, thereby limiting the cutting depth.

A double-cutting shoe as here. disclosed may be provided with such a skid surface extending laterallyvbackward and, outward from: 9.: point near" the inner cutting tip in alignment with upper. portions. only of the. two tips. The: outward cutting movement of such ashoe is limited, perbasket'revolution, to not more than 't-herradial distance'existing between the edge of the outer tipand the: skid; surface, during whichjmovement only the outer tip is active; while on downward movement both tips displace solids and the deepest swath cut per basket revolution is determined by the tip height below the skid surface. When the shoe tends to cut deeper in either direction part of the solids rotating in the basket will engage the skid surface to prevent deeper cutting action.

Furthermore, when such a shoe-works at the basketscreen under pressure sufficient to move the outer cutting tip inward, the skid surface will slide against the screen andprotect it from being gouged bythe inner cutting-tip; 7 Operation 7 especially free from screen abrasion can be obtained under these conditions by making the skid surface and the outer tip of a hard synthetic resin material, which has been found to exert remarkably little friction in sliding contact with basket screens. For this purpose pieces of hard laminated phenol-aldehyde. or urea-aldehyde resin may be used; for example, the material known as Formica.

A double-cutting shoe provided with a skid surface as here disclosed may be used with such alimited force on the movable outer tip that the shoe could not enter the face of a mass of sugar spinning. at high speed in the centrifugal basket, or could cut so little as to cause no damage. Such a shoe therefore can be kept safely inside a centrifugal basket at all times and affords a means for making a simple yet safe automatically discharged cyclical centrifugal machine.

According to a further feature of this invention. easier discharging action and anadvantageous deflection of displaced solids can be obtained by making the discharger shoe as an elongated arcuate body having a cutting tipat the leading edge,. a cutting edge along the bottom and. a facial concavity extending upward from the bottom edge in the forward portion of the shoe face; The concavity proceeds from outward curvature in the-lower forward face portion. into inward curvature in the upper forward face portion; the latter preferably continuing into and alongthe. upper backward face portion while the former merges into a lower backward face portion substantially parallel to the axis of movement of the shoe. The tip at the leading edge of such a shoe body may be formed advantageously as an intersection of the forward concavity by a surface fitting the side wall of the basket. Thus it has forwardly projecting bottom and toppoints with backwardly curved edges converging between. them, yet' it works near the basket screen in substantially parallel relationto the'f-ace of thescreen.

With a construction of this kind, the solids displaced by the shoe body pass freely from its cutting edges into its facial concavity and are then deflected upward and showered inward toward the basket axis.

.Discharger shoes of the type described may be adapted to enter readily into very hard masses. of rotating solids by providing them with digging devices in position towork only as ahard massis being entered by outward shoe movement. If the: shoe body has a, flexible cutting tip leading to: its face, a rigid digging device may project; from the outer side of the shoe body at a location spaced well backward from the tip. In: a. double-cutting. sho having a backwardly disposed flexible cutting tip, theouter tip itself: may serve as such a digging device by providing means to stop its yielding inward movement, as it entersa hard mass to'be discharged, at a point where it still extends beyond the radial position of theinner tip on the shoe body.

The foregoing and other objects, features and-' advantages of this invention will becomeapparent from the following detailed descriptionand? the accompanying drawings of illustrative em.- bodiments. J

In the drawings:

Fig. 1 is a view partly in plan and partly in fueal. basketyand: a suitable discharger operat ing mechanism on the basket curb. The shoe is here shown at an intermediate position of outward movement into a mass of solids rotating in the basket.

Fig. 2 is an enlarged view showing the shoe of Fig. 1 as it may Work at the basket screen; Fig. 3 is a perspective view of the shoe shown in Figs. 1 and 2, looking toward its outer side from a point ahead of its forward end;

- Fig. 4 is another perspective view of the same shoe, looking toward its inner side from a point inline with its inner tip;

Fig. 5 is an elevation of the forward portion and part of the backward portion of the inner fac of the shoe body, as viewed from line 5-5 of Fig. 2; I

Fig. 6 is a sectional outline of the shoe taken at line 66 of Fig. 2;

Fig. 7 is a sectional outline taken at line 1-4 of Fig. 3;

Fig. 8 is a sectional outline taken at line 8-8 of Fig. 3, with part of the upper shield structure broken away;

Fig. 9 is a perspective view of the forward part of another embodiment of the invention;

Fig. 10 is a plan view of the shoe of Fig. 9 in position to enter a mass of solids in a rotating basket, the basket and its contents being shown in horizontal cross section;

Fig. 11 is a view similar to Fig. 10 but showing the shoe at an intermediate position of its outward movement;

Fig. 12 is a similar view indicating the action of the shoe at the basket screen; and

Fig. 13 is a fragmentary perspective view of the forward part of the same shoe, looking at its inner side from a point above and ahead of its inner tip.

Referring to the drawings:

Fig. 1- indicates a centrifugal basket I suspended in usual manner on a gyratory vertical spindle 2 for rotation about its axis A. The basket has a bottom 3 and a centrally open cap or top4. They embrace its cylindrical side wall which comprises a strong perforated shell 5 and foraminous linings 6 that form a filtration screen. A stationary curb I surrounds the basket. The basket is shown rotating in clockwise direction with an annular mass or wall 8 of solids in its being discharged by outward movement of the discharger shoe 10. As the solids are discharged they may fall through openings 3a in the basket bottom.

The movements of shoe H] are brought about through an operating mechanism [2 fixed to the curb top. This mechanism embodies features disclosed in my copending application, Serial No. 712,781, filed November 29, 1946, now Patent Number 2,628,719, but any other suitable mechanism may be used. For present purposes, it is suflicient to mention that the shoe ID has a base II at its backward end fixed to a shaft I3 which is slidable vertically but held against rotation in a guide passage of a housing l4 that is swingable horizontally about a fixed vertical axis at B on the curb top. A handle i 5 extends from housing l4 and can be manipulated by an operator to swing the housing, shaft l3 and shoe Hi inward and outward relative to the basket axis. A hand wheel it connects through housing ht with a pinion l1 engaging a gear rack on shaft I 3,.so that the operator may move th shoe vertically by turning the hand wheel. 7

Essentially, the shoe l0 need only be movable horizontally so as to swing its forward ,end 2| out to and inward from the basket side wall, and vertically so as to move it down and up in the basket. A discharging operation may be effected, as is customary, by swinging it outward through a layer of the mass 8 just below top 4 and then moving it downward along the face of screen 6 to bottom 3, or by moving the shoe part way outward at the top, then downward, and then farther outward at the top and downward again.

The shoe I 0 extends forward from base II as an elongated arcuate body 20 which can lie entirely inside the opening of basket top 4 and can have its forward end 2| swung outward to the face of screen 6 as seen in Fig. 2. A shield structure 22 of known nature extends upward from the back of body 20 to keep solids away from the discharger shaft. The body presents an arcuate face 50 formed to deflect solids toward the basket outlets 3a, as described more fully below.

The forward end of the shoe body carries two laterally spaced cutting

tips

23 and 24. Tip 23 is the leading edge of the shoe body. Tip 24 is formed by a blade member 25 held on the outer end 26 of a pivotal arm 21, which extends backward and outward from body end 21 The inner end of arm 2! carries a pivot pin 23 fitting into a socket in the shoe body, and the arm is held in the socket by head 29 of a screw threaded into that end (Fig. 6).

Thus the arm 21 and cutting tip 24 thereon are swingable laterally relative to the outer side of the shoe body. They have an outer position at which a pin 30 on the arm abuts against an opposing projection 3i from end 2|. At this position movable tip 24 lies at a greater radial distance from the axis of the basket than the fixed tip 23 on the shoe body. A leaf spring set 32 is supported on the top surface 33 of the shoe body and bears at its free end 54 against a part 35 of arm 21, thus holding the arm and its tip yieldably at the described outer position. The leaf springs 32 bear between their ends against a fulcrum on body 26 at 36, and their backward end 31 is engaged by a set screw 38 which is threaded through a backward part'of the shoe body and can be adjusted in position to select a desired spring force.

The spring forceis set at a magnitude insufficient to dig the outer cutting tip 24 into the basket screen. This tip yields and moves inward relative to the shoe body whenever pressure exerted against it exceeds the spring force normally holding it in outer position.

Between the two

tips

23 and 24 and in lateral alignment only with upper portions of their cutting edges, the forward end of the shoe body carries a portion 48 extending outward and backward from the region of inner tip 23. The abutment 3 i for stop pin til on arm 21 is conveniently an inner part ofthis extension. The forward side of extension 40 is faced with a layer M of a hard synthetic resin material, such as Formica. which presents a surface 42 serving as a skid to limit the depth of action of the shoe in the rotating mass of solids. The skid surface begins at a point near the upper portion of the inner cutting tip 23 and extends laterally outward and backward with a curvatureapproximating though sharper than that ofthe basket .side wall, and it is spaced inward toward the basket axis from the normal position of the outer cut-' ting tip 24' so that a limited thickness of rotating "solids: may" pass; outside surface 425170 be. dischargedaiby-"tip 2-4.v

The blade member-25 which. forms the outer tin; like the skid: surface, is preferably a piece of-ahardsynthetic resin material such as Formica- This maybe held in place by channels 25aon. therouter end of arm 21.

The;:inner' cutting tip 23 in this embodiment acts: principally during the downward discharging movements of shoe I0, although it might act during outward movements also in the absence of the; skid surface. The shoe face 50 extends backward from tip 23 above a long cutting edge 5I at the bottom, and any solids rotating inside thesetwo edges are displaced so as to pass over face. 50 and be deflected efficiently by it. toward the center of the-basket. For the latter purpose, the forward portion of face 50 extends upward fromthe bottom cutting edge in a concave form composed of an outwardly curved lower forward face portion 52 and a merging inwardly curved upper." forward face portion 53. The cutting tip 23 is formed as an intersection of these curved surfaces by a surface fitting. the basket side. wall. Tip 23 therefore works near screen fi in a vertical plane substantially parallel to the screen, as will be evident from its appearance in Fig. 4, and it possesses .a complex outline comprising forwardly projecting

points

54 and 55 at bottom and top with backwardly curving

convergent edges

56 and 51 between these points. See Fig. 5;

As indicated further in Figs. 4, '7 and 8, the upwardly inward curvature of the upper forward face portion 53 continues into and along the upper backward portion 53a of' the shoe face. On theother hand, the upwardly outward curvature of. the lower face portion 52 merges along, the shoe into a lower backward face portion 52a which is substantially vertical, 1. e., parallel to the axis of shoe movement. See Fig. 8. Fig. 7 shows a sectional outline of the shoe body at an intermediate place where its lower face portion has begun to straighten vertically.

In order to facilitate entrance of the discharger shoe into the face 9 of a hard mass of solids, the arm 21 may carry a stop member 58 aligned with an abutment 50 on the outer side of the shoe body; If the solids at. 9 resist penetration by tip 24 strongly enough to overcome the force of spring 32, arm 21 may flex inward until

parts

53 and 59 abut to hold the tip rigid. At this-point tip 24 still lies radially outside tip 23. Entrance into the face of the mass then may be effected by applying increased outward force to the-shoe.

The operation of this preferred embodiment will be evident from what has been described but may be summarized as follows:

With thebasket I rotating slowly, sayat 50 R. P. M., the forward end of the shoe is first swung outward into the top of the mass of solids, and entrance into the mass is effected by action of the outer tip 24 which either enters immediately orflexesinward to become rigid and then enter in the manner just described. As the shoe is moved further outward toward the basket screen a top layer of the rotating solids is removed against tip 24, which deflects the solids inward at the back of the shoe body. In each basket revolution tip 24 cuts out a swath limited in thickness to not more than the radial distance existing between its edge and the skid surface 42. As diagrammed in- Fig. l, the face 8a of'the rotating' mass, from which a swath was last removed, firmly supports the skid surface while the outer tipi isremoving another swath. Theshoe there- 8 fore cannot. be. inserted too fast; or: toodeeply into the charge.

When the shoe reaches; the. basketscreen only a thin layer of solids, as indicated at flb-in Fig.2; may remain to'be scraped fromthe screen bythe outer cuttingtip. If stops I8 and jI9; on the discharger mechanism (Fig. 1) have notstopped.

the shoe with tip 24 exactly at the screen, this tip may engage the screen and flex inward against the force of spring 32, as diagrammed in Fig; 2, without causing damage to thescreen. The thin layer of solids rotating against: tip 24 does: not cause it to dig into the screen. Andif it flexes inward under heavy enough. pressure, the skid surface 42 will engage and slide on the screen-to keep the rigid inner tip 23 from digging into: the

screen.

A top layer having been removed, the: shoe -I 0 next is moved downward inthe rotating mass. In this movement most of the thickness of'mass 8 is displaced over the face of the shoe body by action of its cutting tip 23 and itsbottom cuttin edge 5I; so the shoe body bears the main-pressure of the mass. The flexible outer. tip 24 continues, however, to act on a thin layer of'solids at the face of the screen as it did when reaching; the screen onv the outward shoe movement, its work being confined to the removal of solidsv left .between inner tip 23 and the face ofv the screen. Andv the depth of cutting per basket revolution continues to be limitedby the skid surface42, for if the shoe cuts deeper than theheightbetween point. 54. and the bottom of. skid 42,.theskidwi1l be engaged by part of the rotating massto thrust the shoe away from its working position- The solids displaced. along thefcutting edges of face 50 move freely into-its forward concavity over the upwardly outwardly curved lower. surface 52 and are deflected upward. andthen inward by the upwardly inwardly curveduppersurface 5353a, which. showers them toward. the basket bottom openings 3a.

Referring now to the second illustrative em.-

bodiment of Figs. 9 to 13, these show the forward portion of a modified conventionalshoe. body I00 which has been provided according to thepresent invention with double cutting tips I03. andLIIiO, with a skid surface II4 betweenthem, and with a special form of digging devicedisposed. backward from the outer cutting tip at. I20.

The. shoe body again is an elongated arcuate member, but here it has an inner face I02. of. known form. A flexible cutting tip I03 is carried at its leading end I04 but extends forward and outward from this: end to deflect solids to its face. Tip I03 is on the free end of a movable. arm I05 that. reaches backward along the outer side of. the shoe body to a fulcrum pin I06, beyond which the backward arm'end I0! is held. under tension by a spring I08. The spring I08 thus holds tip I03 yieldably in an outward position. Its normal location is determined by a stop pin I09, but .it can move inward relative to the shoe body under pressure exceeding the force of the spring- The other cutting tip I I0 is provided ahead of the flexible tip I03 on a rigid member III which extends forward from the top of the shoe. body and presents an inner surface I I2 leading to the shoe face I02. Tip H0 is the leading edge of surface H2 and is disposed at a shorter radial distance from the basket axis than theedge of tip I03. r

The skid surface H4 is provided on a part'of. member III which extends outward, and backwardfrom an upper portion of the inner'cutti'ng, tip 0. Again, the skid surface is formed with side of the shoe body carries a digging device consisting of two rigid projections I20 which terminate in blades lying transverse to the axis of shoe movement. These blades extend to a radial position about as far as that of the edge of tip I03 when the shoe is in position to enter the face 9 of a mass of solids in the centrifugal basket. Accordingly, if the mass resists penetration strongly enough to move tip I03 inward against the force of spring I08, the blades I20 will break into the face of the rotating solids as diagrammed in Fig. 10. Then tip I 03 comes into action.

As outward movement of shoe I continues the flexible outer tip I03 works to displace successive swaths of solids limited in thickness by the radial distance between its leading edge and the skid surface I I4. The action is diagrammed in Fig. 11 and proceeds substantially as described in connection with the first embodiment, except that the displaced solids pass over the shoe face I02 instead of being deflected back of the shoe as in Fig. 1. I

When the outer tip I03 reaches the basket screen it works there in much the same way as the outer tip of the first embodiment, as diagrammed in Fig. 12. In this case, however, tip I03 preferably is made with a blunt leading edge II5 so that pressure of solids rotating against this edge will tend to move it inward and thus counteract the opposite tendency of solids moving against its inner face.

During downward movement of shoe I00 along the basket screen, the bulk of the rotating solids is displaced inside the fixed inner tip I I0 over the surfaces H2 and I02, while the flexible outer tip continues to displace only a limited layer of solids moving between tip H0 and the basket screen. As previously described, the skid surface I I I positively prevents tip I ID from pressing into the screen. The rate of downward cutting is limited by action of the skid surface in substantially the manner described in connection with the first embodiment.

It will be evident that the new features here disclosed and claimed may be embodied in various forms of centrifugal discharger shoes diifering from the illustrative forms described above.

What I claim is:

1. In a centrifugal discharger including a discharger shaft to extend into a centrifugal basket and an elongated shoe projecting radially from the shaft, the shaft and shoe being adapted to be turned about a fixed axis substantially parallel to the basket axis in the same angular sense as the sense of basket rotation so as to swing the shoe outward through solids rotating in the basket, and then to be moved downward in the basket through such solids, a discharger shoe body, two laterally aligned solids discharging tips at and carried by the leading end of said body, one of said tips being at a greater radial distance than the other from the basket axis throughout the path of swinging movement of the shoe, so that said one tip leads the shoe into the rotating solids during its outward swinging movement and both tips discharge swaths of solids during its downward movement.

2. In a centrifugal discharger including a discharger shaft to extend into a centrifugal basket and an elongated shoe projecting radially from the shaft, the shaft and shoe being adapted to be turned about a fixed axis substantially parallel to the basket axis in the same angular sense as the sense of basket rotation so as to swing the shoe outward through solids rotating in the basket, and then to be moved downward in the basket through such solids, a discharger shoe body, two

laterally aligned solids discharging tips at and carried by the leading end of said body, one of said tips being at a greater radial distance than the other from the basket axis throughout the path of swinging movement of the shoe, so that said one tip leads the shoe into the rotating solids during its outward swinging movement and both tips discharge swaths of solids during its downward movement, and means yieldably mounting said one tip and that it is movable inward relative to said body against said yieldable means under excessive basket pressure.

- 3; In a centrifugal discharger including a discharger shaft to extend into a centrifugal basket and an elongated shoe projecting radially from the shaft, the shaft and shoe being adapted to be turned about a fixed axis substantially parallel to the basket axis in the same angular sense as the sense of basket rotation so as to swing the shoe outward =.through solids rotating in the basket, and then to be moved downward in the basket through such solids, a discharger shoe body, two laterally aligned solids discharging tips at and carried by the leading end of said body, one of said tips being at a greater radial distance than the other from the basket axis throughout the path of swinging movement of the shoe, so that said one tip leads the shoe into the rotating solids during its outward swinging movement and both tips discharge swaths of solids during its downward movement, and means yieldably mounting said one tip so that it is movable inwardrelative to said body against said yieldable means under excessive basket pressure, the other of said tips being fixed relative to said body in position to lead solids over the inner face of said body.

4. In a centrifugal discharger including a discharger shaft to extend into a centrifugal basket and an elongated shoe projecting radially from the shaft, the shaft and shoe being adapted to be turned about a fixed axis substantially parallel to the basket axis in the same angular sense as the sense of basket rotation so as to swing the shoe outward through solids rotating in the basket, and then to be moved downward in the basket through such solids, a discharger shoe body, two laterally aligned solids discharging tips at and carried by the leading end of said body, one of said tips being at a greater radial distance than the other from the basket axis throughout the path of swinging movement of the shoe, so that said one tip leads the shoe into the rotating solids during its outward swinging movement and both tips discharge swaths of solids during its downward movement, and means yieldably mounting said one tip so that it is movable inward relative to said body under excessive basket pressure, the other of said tips being fixed relative to said body in a position to lead solids over the inner face of said body, and a lateral passageway between said one tip and the outer side of said body for the free escape therebetween of solids discharged by said one tip. I

5. In a centrifugal discharger including a discharger shaft to extend into a centrifugal basket and an elongated shoe projecting radially from the shaft, the shaft and shoe being adapted to be turned about a fixed axis substantially parallel 1311 to the basketaxis. in; the samegangular sense; as the-sense .of-basket rotation so gasjtow swing the shoe. outward .through solids rotating in the basket, and then to: be. 1noved downward in the basket; through such solids, a-discharger shoe body, two laterallylaligned solids-discharging tips at the leading end .of ,said.- body, ,a;nd means for holding one of .said .tips at ,a greater 1 radial distance than the other --from the basket axis throughout the .path. of swinging movement of the shoe, so that said .onetip leads-the shoe into the. rotating solids during .its outward sw n in movement and both tips discharge swaths of I solids during its downward movement, said hold 1 ing means comprising-an arm swingable relative to said bodywon an axis substantially parallel; to .the axis. .of. shoe movement, said onetip bein on the free endeotsaid, arm, and. spring means biasing said.-.arm,-to ran outermost position.

6. .In a centrifugal .discharger. including a discharger. shaft. to extend into .a centrifugal. basket 1 and an 'elongated. shoe projecting-.radially from the shaft,'the shaft and shoebeingadaptedto be i turned about a fixed axis; substantially parallel the sense :ofbasketrotation..so as .to .swingthe shoe outward through isolids .rotating in the basket,.-.and.- then! to. be.moved downward. in the basket through. such solids, .-.a discharger shoe body, two laterallyialigned;solids dischargingtips at the leadingend ,ofvsaidgbody, .and means for holding-done ofsaid-tips-atl a-greater radial distance than the .other .from. the basket axis throughout a the path of .swinging. movement of ithe shoe sothat said-one tipileads thev shoe into the rotating.-. solids during 1 its outward. swinging --movement-and--both tips-discharge swaths of solids during its downward. movement, said holding means comprising an. arm swingablerelative =to saidbody on an axis substantiallyv parallel to the axis of shoe'movement, -said one tip being --on-the-freeend ofsaid arm and spring means biasing said arm to an outermost position,..said spring: means including a leaf. spring bearing at ene end against said arm-and at the other end against an abutment-fixed relative to said. body.

7. Ina centrifugal discharger including .a dis- --charger shaft to extend into a-centrifugal basket and an elongated shoe projecting radially from theshaft the shaft and-shoe being adaptedto' be turned about a fiXed axis substantially parallel tothe basket axis in the same. angular-sense as the sense of basket rotation so as toswing the shoe outward through solids rotating in the basket, and then to bemoved. downward in. the basket throughsuch solids,- a discharger shoe body, two laterally aligned solids discharging-. tips -at= the leading end of said. body, and meanszfor holding one of saidtipsat agreater radialdistalnce than the other from "the basket axis throughout the path of swinging movement. of the shoe, so that said one tip leads the shoe into the rotating solids during its-outward'swinging movement and both tips discharge swaths of solids during its downward movement, said holdingmeans comprising- -an--.arm swingable relative to saidbody on aniaxis substantially parallel to ;the-axis -of shoe movement, said one: tip. being on the-"free end ofsaid arm, and spring means biasing said arm to an outermostposition, saidarm being pivoted to and extending backward from a forward part of saidbody.

:8; A :centrifugal .gd-ischarger as described in claim 7,..and, cooperative means on-said body and said arm for. stopping inwardrelative; movement -;1.of.. .sai d@arm: atzia pos tion -.wher 55 3.65.0 .tip

thereo.n.-;is; still -outside a ado hen ip.

9. -A..disch.arger shoe: for. removing; solids from a rotating centrifugal; basket linediwith a fi'ltration screen, comprising an elongatedashoezbody to the basket axis .in.-.the.. same; angular.- sense as posed outside the other to act .at a greaten-radial 1O. distance from the axis of thebasket and being sure,.-and. an outwardly facing. skid carried- .by. said .1 body. .between the'two tipsand having its .workmovable. inward relative-to said body. under.r.presing surface. in lateral alignment withupper portions only of said tips and'spaced radially inward from the normal position of. thetleading edge-of the outer tip for' limiting-the rate of discharging hy-riding on partof the rotating solids.

- 10. .A discharger-shoe as; described in clai-m 9, said innertip being the leading edge of theshoe bodysand said-skid having its surface extending back-ward and outward on a part of said body from a point near said edge.

11. A'discharger shoe as described in claim 10,

said screen.

12. Adisoharger shoe as described in claim 11, the-working surface of saidskid-being composed of a hard synthetic resin-material to-limit-its frictionin-contact with said screen.

13. A dischargershoefor removing solids from a rotating centrifugal basket, comprising an tendingcutting edge along theleading andedge of said'face, said cutting edgelying substantially parallel to the basket'si'de wall when the shoe is -at'its outmostposition adjacent thereto, and a substantially straight-concave cutting edge along the bottomof said-face, the forward portion of saidfacebeing curved concavely upward from said bottom cutting edge with upwardly outward curvature inthe lower "portion-merging into upwardly inward curvature inthe upper portion.

l4. Adischarger shoe as; described in claim 13,

"the upwardly-inward curvature continuing-into V and along the backward-upper portion of said face and theupwardly outward curvature rnerging along said face into a backward-lower=face portionsubstantially parallel to the axis of-movemerit of the shoe.

l5. :A- discharger shoe. for removing solids from a rotating centrifugal basket, cempr-isingan elongated arcuate shoebody adapted tobe swung outward into solids "rotating in-the basket'and then lowered into such solids; said body having --a =-longitudinallyconcave inner face 'for' deflecting solids, a cutting tip presentingan upwardly extending: cutting edge along the lead-ing-andedge on said face, said-cutting edge lying substanstantially to an intersection of said curvatures by a surface fitting the side wall of the basket.

16. A discharger shoe for removing solids from a rotating centrifugal basket, comprising an elongated shoe body movable radially outward in the basket to discharge solids therefrom and carrying at a radially outward point a cutting tip acting to displace the solids upon such outward movement, and an outward facing skid fixed on said body having its face aligned laterally with said tip but spaced radially inward therefrom and forwardly therefrom in the direction of approach of solids to be discharged, to limit the cutting depth of said tip by sliding contact with part of the rotating solids.

17. A discharger shoe for removing solids from a rotating centrifugal basket, comprising an elongated shoe body carrying at a radially outward point a cutting tip acting so displace solids when moved thereinto either outward toward or axially along the basket side wall, and a ski-d fixed on said body having an outwardly facing surface aligned laterally with an upper portion only of said tip and spaced a predetermined radial distance inward therefrom and forwardly therefrom in the direction of approach of solids tobe discharged, so that part of the rotating solids may bear against said skid to limit the cutting depth of said tip to a swath not thicker than said distance during the outward tip movement and to a swath not exceeding the tip height below said skid during the axial tip movement.

18. A discharger shoe for removing a rotating annular mass of solids from the side wall of a centrifugal basket, comprising an elongated shoe body having a forward end to be swung outward to the basket side wall and carrying at said end two laterally aligned spaced discharging tips, o ne of said tips being yieldably mounted to act at a greater distance from the axis of the basket than the other, an outwardly facing skid fixed on said body in laterally aligned relation to and between said tips and having its working surface disposed at a distance from such axis less than that of the yieldably mounted tip in its outermost position but always more than that of the other tip.

19. A discharger shoe for removing solids from a rotating centrifugal basket, comprising an elongated shoe body carrying at its outermost'point a yieldably mounted cutting tip acting to displace the solids upon movement outward thereinto, a skid on said body having its working surface aligned laterally in front of said tip, but spaced inwardly of the outermost position thereof, and a digging device mounted in laterally aligned relation with said cutting tip and spaced inwardly of the outermost position thereof but outwardly of said skid surface.

20. A discharger shoe for removing solids from a rotating centrifugal basket lined with a filtration screen comprising; an elongated shoe body having an inner face, a cutting tip at the leading edge of said face and a cutting edge along the bottom of said face, wherein the forward portion of said face is curved concavely upward from said cutting edge with upwardly outward curvature in the lower portion merging into upwardly inward curvature in the upper portion; a second tip normally disposed outside the other to act at a greater radial distance from the axis of the basket and being movable inward relative to said body under pressure; and a skid carried by said body between the two tips in lateral alignment therewith and having its working surface spaced radially inward from the normal position of the leading edge of the outer tip but outward of the first named tip.

21. A discharger shoe for removing solids from the side wall of a rotating centrifugal basket comprising an elongated shoe body movable axially along the basket side wall and carrying a cutting tip to displace a swath of solids upon each rotation, and a skid fixed on said body having a downwardly facing surface aligned laterally with a portion of said tip above the lower edge thereof and disposed angularly forward thereof in the direction of approach of solids to be discharged to limit the depth of the swath cut by riding on the surface of the rotating solids formed while removing a swath in the prior rotation of the basket.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,012,766 Vives Dec. 26, 1911 1,042,710 Moore Oct. 29, 1912 1,102,530 Mackintosh July 7, 1914 1,388,173 Daniels Aug. 23, 1921 1,431,016 Mackintosh Oct. 3, 1922 1,701,731 Schaum Feb. 12, 1929 1,968,491 Jones July 31, 1934 2,076,516 Roberts Apr. 6, 1937 2,280,681 Altgelt Apr. 21, 1942