US3677403A

US3677403A - Tumble screen conveyor

Info

Publication number: US3677403A
Application number: US882633A
Authority: US
Inventors: Claude F Young; Richard O De Weese
Original assignee: Union Carbide Corp
Current assignee: Elkem Metals Co LP
Priority date: 1969-12-05
Filing date: 1969-12-05
Publication date: 1972-07-18
Anticipated expiration: 1989-07-18
Also published as: DE2059515C3; DE2059515B2; NO134449B; NO134449C; DE2059515A1

Abstract

A tumble screen conveyor for use in imparting a gentle tumbling action to alloy sizes for removing fins or friable protrusions from their surfaces while simultaneously separating the desired alloy sizes from an admixture of fines of the alloy and/or from other material added to the alloy for insulation or quenching purposes.

Description

United States Patent Young et a].

[ 1 July 18,1972

[54] TUMBLE SCREEN CONVEYOR [72] Inventors: Claude F. Young, Niagara Falls; Richard 0. De Weese, Tonawanda, both of N.Y.

[21] Appl. No.: 882,633

52 US Cl ..209/308, 209/84 [5 1] Int. ..B07b H10 [58] Field 01 Search ..209/307, 308, 106, 98, 84, 209/92, 3; 171/127, 14, 15; 198/1 [56] References Cited UNITED STATES PATENTS 864,829 9/1907 Callow ..209/308 X 889,673 6/1908 Franz ..209/307 915,1 10 3/ 1909 Pickel ..209/308 973,597 10/1910 Wedge ..209/307 1,019,041 3/ 1912 Green ..209/307 1,032,375 7/1912 Boggs ..209/307 1,459,854 6/1923 Nelson ..209/308 X 864,827 9/1907 3,102,857 9/1963 Davenhauer ..209/308 FOREIGN PATENTS OR APPLICATIONS 117,449 10/1942 Australia ..209/84 329,922 12/1920 Germany ..209/84 Hoffeld ..209/307 X Primary Examiner--Frank W. Lutter Assistant Examiner-Robert l-lalper Attomey-Paul A. Rose, Robert C. Cummings, Frederick J. McCarthy, Jr. and Cornelius F O'Brien [57] ABSTRACT A tumble screen conveyor for use in imparting a gentle tumbling action to alloy sizes for removing fins or friable protrusions from their surfaces while simultaneously separating the desired alloy sizes from an admixture of fines of the alloy and/or from other material added to the alloy for insulation or quenching purposes.

6 Claims, 3 Drawing figures Patented July 18, 1972 FIG-3.

INVENTORS C.FRANK YOUNG RICHARD O. DEWEESE QZZMEFM ATTORNEY TUMBLE SCREEN CONVEYOR FIELD OF THE INVENTION This invention relates to a tumbling apparatus for use in removing friable extensions or fins from the surface of cast or formed alloy sizes while simultaneously separating such alloy sizes from alloy fines and off-size pieces.

DESCRIPTION OF PRIOR ART It is the present practice to employ vibrating or oscillating screens for separating desired alloy shapes from an admixture of fines of the same alloy and/or from other material added to the alloy for insulation or quenching purposes. The severity of the vibrating or oscillating motion that is imparted to the alloy sizes is usually enough to shatter the soft friable alloy pieces into unusable off-size pieces thus increasing the expense of the final product.

Additional machinery is also required to remove the alloy sizes from the screens and transport them to a packaging or loading destination.

Another method usually employed in separating alloy sizes from an admixture of fines of the same alloy is to utilize fork type instruments to actually lift the alloy sizes out of the mixture.'This technique however does not remove the fins or friable extensions from the surface of the alloy sizes and consequently such fins or friable extensions are usually broken off during transit where they create a mixture of fines and alloy sizes which presents a real problem when the alloy product is for use in shaft furnaces or the like.

SUMMARY OF THE INVENTION Broadly, the object of this invention is to provide a single tumble screen conveyor-type apparatus which can separate fines and off-size alloy pieces from desired alloy sizes while simultaneously removing fins or friable protrusions from the surface of such alloy sizes.

This tumble screen apparatus employs an endless conveyor screen belt having apertures smaller than the desired alloy sizes to be conveyed but large enough to pass alloy fines and off-size alloy pieces there through. The screen belt is sprocket driven by motor-powered, sprocket wheels and is sufficiently long in length to allow slacks in the screen between adjacent sprocket wheels. A translatable idler sprocket wheel is positioned outside of the circumference of the endless screen belt and contiguous therewith so that by being moved into or away from the belt it can impart a tightening or loosening effect, respectively, on the belt which in turn will decrease or increase, respectively, the catenary curve of the slacked belt between adjacent sprocket wheels.

Cast or formed alloy sizes are deposited on one end of the conveyor belt and during conveyance they are gently tumbled upon themself in the catenary curved pockets so that the selfabrasion force encountered therefrom is sufficient to remove any fins or friable protrusions from the alloy sizes without shattering or breaking up the useable soft friable alloy sizes. The desired alloy sizes are then discharged from the conveyor and ready for shipment.

An inclined chute is appropriately placed between the upper forward feed section and the lower return section of the belt and extended at least a fraction of the width of the belt so as to catch and direct away from the lower return section of the belt the fines and off-size alloy pieces being separated from the alloy sizes by passing through the upper feed section of the belt. A container may be placed adjacent the lower edge of the chute for collecting the fines and off-size alloy pieces.

A variable speed motor may be employed to drive the sprocket wheels so that the self-abrasive tumbling motion imparted to the alloy sizes being conveyed can be increased or decreased depending on the particular alloy being conveyed.

The sprocket drive wheels between which the catenary curved pockets are formed have to be timed and driven at the same speed in order to maintain the shape of the pockets con- Siam.

A container may be placed directly below and adjacent the end of the conveyor to collect the discharging alloy sizes which can then be immediately shipped to their final destination.

The sprocket wheels and conveyor belt may be adjusted to eliminate certain slack pockets so that the conveyor can function normally for a predescribed distance before incorporating the tumbling action.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is an elevational side view of the apparatus employed in the invention.

FIG. 2 is a sectional view of the apparatus shown in FIG. 1.

FIG. 3 is a top view of the apparatus shown in FIG. 1.

Referring to the drawings there is shown in FIGS. 1-3 an endless screen conveyor belt 1 driven by sprocket wheels 2 which are powered by motor 3. Each sprocket wheels 2 is designed with the same number of teeth and all are driven at the same speed by means of driving chains 16. This insures that the catenary shaped pockets between adjacent wheels are kept constant. The conveyor is supported on housing frame 4 equipped with parallel guide panels 5 widthwise enclosing the forward feed section of the conveyor belt. The guide panels provide a confining means for holding the conveyor screen in proper alignment with the sprocket wheels while also furnishing a barrier or containing type wall for alloy sizes transported on the conveyor belt.

Screen belt 1 has female sprocket receptacles 6 which mate with the teeth on sprocket wheels 2 and has apertures 7 disposed throughout the belt which are smaller than the alloy sizes to be conveyed and larger than the fines and off-size alloy pieces to be separated from the alloy sizes.

Idler sprocket wheel 8 is arranged outside of and contiguous with the midway section of the return portion of the endless belt and is translatable to impart a tightening or loosening effect on the belt when desired.

.Feed sprocket wheels 2 and return sprocket wheels 9 are designed with the same number of teeth for mating with specific female receptacles on the conveyor belt so that the size of the slack pockets provided between adjacent sprocket feed wheels can be maintained constant since all the feed sprocket wheels are timed to operate at the same speed. To alter the catenary curve of the slack pockets, idler sprocket wheel 8 is translated into or away from the conveyor belt thereby tightening or loosening the belt, respectively. Thus one or more slack pockets can be provided in the conveyor belt, depending on the number of feed sprocket wheels.

FIG. 2 shows chute 10 with side plates 11 assembled inside conveyor screen belt 1 between the feed and return sprocket wheels at an angle of between about 15 to about 75 made with reference to the horizontal edge of screen belt 1. The chute extends the width of the conveyor belt so as to be in a position to catch and direct alloy fines and off-size pieces passing through apertures 7 in the conveyor belt. Container 12 is disposed directly below and adjacent the lower edge of chute 10 to receive the alloy fines and off-size pieces.

Container 13 is positioned directly under and adjacent the end of the conveyor belt for receiving the sorted alloy sizes which are in condition for shipment to their final destination.

In the operating mode of the tumble screen conveyor, alloy sizes are deposited on one end of the conveyor belt and while being transported they are gently tumbled upon themself producing a self-abrasive action while in the overall process they are advanced into and carried out of the slack pockets between adjacent feed sprocket wheels. This gentle self-abrasive, tumbling action imparted to the alloy sizes is sufiicient to remove fins or friable protrusions from the alloy surfaces while insufficient to break up soft friable alloy sizes. During the conveyance of the alloy sizes, fines and off-size pieces 14 pass through the apertures in the conveyor belt and are directed by means of inclined chute 10 to container 12 where they are collected. The relatively smooth finless alloy sizes 15 that reach the end of the conveyor belt are deposited into container 13 where they are ready for further shipment.

By moving the idler wheel and/or varying the drive speed of the feed sprocket wheels, the duration and severity of the selfabrasive tumbling action can be regulated as desired to accommodate different requirements of different alloy sizes.

Translatable sprocket wheels may be employed so that the horizontal length and/or the vertical height of the slack pockets can be varied.

Instead of an inclined chute disposed between the forward feed segment and the return segment of the endless screen belt of a conveyor preferably power driven may be disposed therebetween at an inclined angle between about and about 80 made with reference to the horizontal edge of the screen belt. This conveyor could then catch and carry the fines upwardly to be deposited in a larger size box or even to be fed into a feed chamber of a briquet forming apparatus.

Friction drive wheels or any other positive driving means may be used to drive the screen belt.

EXAMPLE A four feed-sprocket-wheel tumble screen conveyor was employed to gently tumble 30,000 lbs. of pressed formed 50 percent ferrosilicon briquets about two inches by two inches. The briquets had as much as Vs inch friable edge projections due to the land area associated with press forming. A thirtyfoot screen belt having apertures about A inch by one inch formed the endless conveyor belt. Three catenary curve pockets were provided between the adjacent feed sprocket wheels with each having a maximum vertical depth at its center of about six inches to eight inches and a horizontal length of about 2- /2 feet. The feed sprocket wheels all had 14 teeth and were power driven by a 0 to 20 R.P.M. motor.

A batch of 50 percent ferrosilicon briquets was deposited on one end of the conveyor belt and with the motor set to produce 2 R.P.M. for the drive sprocket wheel the briquets, gently tumbling upon themselves, were conveyed into and carried out of the three slack pockets. This gentle tumbling action was sufficient to abrasively remove the friable edge projections from the briquets while being insufficient to break up the soft friable briquets. A container at the side of the conveyor belt received by means of an inclined chute the edge projections and off-size pieces that fell through the apertures in the conveyor belt. An additional container placed at the end of the conveyor belt received the final briquets.

The tumble screen conveyor operated so gently that the soft friable briquets, that formerly would have been broken if the vibrating or oscillating screen technique was employed, were saved thus increasing the final useable briquet output by about percent or more over that obtainable from either the vibrating or oscillating screen technique. The useable briquet output is that portion of the original briguets fonned that maintain their two inch by two inch size.

In addition, the final briquets were moved to their final destination point on the conveyor thus eliminating handling with tote boxes, skips and the like.

Castings of manganese-silicon and vanadium were tumbled on the conveyor screen and increases in the output of useable alloy sizes were again noted.

What is claimed is:

1. An apparatus for gently tumbling alloy sizes to remove friable fins on the surface of said alloy sizes while simultaneously separating fines from said alloy sizes comprising:

a. endless screen belt having apertures smaller than alloy sizes to be carried and tumbled thereon;

b. (two or) more than two sprocket wheels in tandem for driving said screen belt each of said wheels being timed and driven at the same speed, and means assembling said wheels so that (at least one) a catenary curve slack pocket is provided in the screen belt segment between adjacent drive wheels so as to produce more than one slack pocket in said belt, each of said (pocket ockets having a horizontal length and vertical height su tcient to enable alloy sizes being conveyed within said pocket to be tumbled upon themselves so as to produce a self-abrasive action sufficient to remove friable protrusions from the surface of the alloy sizes; and

c. motor means for driving said wheels which conveyed thereon can be gently tumbled into and out of the slack (pocket) pockets thereby producing a self-abrasive action sufficient to remove fins of the alloy sizes which can then pass through the apertures in the screen.

2. The apparatus as in claim 1 wherein said sprocket wheels have equal number of teeth and are driven at the same speed so that when said teeth advance the endless screen belt the slack pocket provided between adjacent sprocket wheels will be maintained constant.

3. The apparatus as in claim 1 wherein said sprocket wheels are (adjustable) translatable sprocket wheels so (as) that (to increase or decrease the length and depth of at least one of) the catenary curve of each slack (pockets provided in the endless screen belt segment) pocket between adjacent sprocket wheels can be varied.

4. The apparatus as in claim 1 wherein a translatable idler wheel is disposed outside of and contiguous with said endless screen belt so that movement into or away from said endless screen belt will tighten or loosen said belt, respectively, thereby changing the catenary curve of the slack pocket between adjacent sprocket wheels.

5. The apparatus as in claim 1 wherein an inclined chute extending at least a fraction of the width of the endless screen belt is disposed between the forward feed segment and the return segment of the endless screen belt so that it can catch and direct fines of the alloy sizes which pass through the apertures of said forward screen belt segment to the side of the apparatus.

6. The apparatus as in claim 5 wherein said chute is disposed at an angle between about 15 and 75 with respect to the horizontal edge of the endless screen belt.

Claims

1. An apparatus for gently tumbling alloy sizes to remove friable fins on the surface of said alloy sizes while simultaneously separating fines from said alloy sizes comprising: a. endless screen belt having apertures smaller than alloy sizes to be carried and tumbled thereon; b. (two or) more than two sprocket wheels in tandem for driving said screen belt each of said wheels being timed and driven at the same speed, and means assembling said wheels so that (at least one) a catenary curve slack pocket is provided in the screen belt segment between adjacent drive wheels so as to produce more than one slack pocket in said belt, each of said (pocket) pockets having a horizontal length and vertical height sufficient to enable alloy sizes being conveyed within said pocket to be tumbled upon themselves so as to produce a selfabrasive action sufficient to remove friable protrusions from the surface of the alloy sizes; and c. motor means for driving said wheels which conveyed thereon can be gently tumbled into and out of the slack (pocket) pockets thereby producing a self-abrasive action sufficient to remove fins of the alloy sizes which can then pass through the apertures in the screen.

6. The apparatus as in claim 5 wherein said chute is disposed at an angle between about 15* and 75* with respect to the horizontal edge of the endless screen belt.