US 2276333 A
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March 17, 1942.
M, ovEsTRup 2,276,333 APPARATU AND METHOD FOR CRUSHING AND SEGREGATI NG MATERIALS Filed Dec. 14, 19:59 2 sheets-s eet 1 Nay/Iv 0023772410 March 17, 1942.' M. OVESTRUD 2,276,333
APPARATUS AND MliTl-IOD FOR CRUSHING AND SEGREGATING MATERIALS Filed Dec. 14, 1959 2 sheets'sheet 2 II J 1 4 7 k MELVIN Ovsarzw s'ra'ras APPTUS AND METHOD FOR CRUSHHVG AND SEGREGATING MATER s Melvin Ovestrud, Minneapolis, assignmto Pioneer Enging Works, c., apolis, Minn, a comration ofimeiaware Application December It, 1939, Serial No. 309,204
8 Claims. (ill. 83-93) This invention relates generally to an improved Output of aggregate. A further object is to proapparatus and method for crushing stone, rock vide an improved crushing method making posand similar materials and segregating the crushed sible the better handling and crushing of the m material in desired sizes. te al and particularly suited to the production of The invention particularly aims to provide an such chips in the quantity desired. improved apparatus and method for the provision These and other more detailed and specific obof a crushed stone aggregate for use in the conjects will be disclosed in the course of the followstruction and maintenance of highways. In work log specification, reference being bad to the acupon highways of the kind having a hard surface companying drawings, in whichcomposed of a mixture of bituminous or asphaltic Fig. 1 is a diagrammatic view of a crushing oils and crushed stone aggregate it has been plant showing the essential crushing and conveyfound that one of the very important component ing elements thereof and with my invention in ingredients is a specially prepared and sized corporatedtherein.
crushed rock aggregate known popularly under Fig. 2 is an enlarged vertical cross se tion the name of chips. These chips are mad by to through the screen assembly used in screening crushing the rock to a comparatively small size, out the various sizes of materials, this view being so that, for example, the chips will pass a screen t ken ppr xima ely 0n the line 2- -2 in Fig. 3.
having one-half inch square openings but will Fig.3 is an enlarged side elevation of the main b retained upon a screen having one-quarter portion of the plant, with a side fragment broken inch square openings. The resulting material out to show interior construction.
when used on th highways has the very desirable In describing my invention reference will first features of increasing traction and offering bet- 'be had to the diagrammatical showing of Fig. 1 ter visibility as is commonly appreciated. in which reference character A designates 2.
However, in the construction of such highways, frame and B the wheels upon which said frame is particularly in regions remote from rock or gravel 2 supported for transport purposes. crushing plants, it has been found very costly to Supported on the frame A is a large delivery purchase the required chips. Even though the and mixing hopper 5 which clumps at its open construction or maintenance project may have lower end 6 into a side delivery conveyor 1 for carin operation at the site a portable rock crushing ryingoff the crushed aggregate. Above the large plant of the usual type, the cost of producing such upper end of the hopper is mounted a vibratingchips is prohibitive. This is due, first, to the fact screen unit in which a total of three and one-half that the tightening down of all crushing elements decks or screens are provided, all of said screens of the plant so retards production that the operbeing, in the assembly here shown, inclined ation cost, per ton of chips, is very high; and seclengthwis or endwise to cause the material to ond,-to the fact that the very nature of the chips travel towards their lowermost ends, although requires that all material of less size than, for exsaid screens may be horizontal if desired. ample, one-quarter inch, must be screened out The lower full deck or screen 8 is the initial reand wasted. This loss or wasta e in actual pracceiving deck for the raw material, which is tice amounts to the order of forty-five Percen Of dumped upon the upper end of the deck by a conthe actual material. The net resultissuchahigh veyor 9 leading from the gravel pit or feeding cost of production that the chips are usually hopper t h course, by any other bought from some remote plant Where Special suitable feeding means. This deck is preferably q p e s used, or where ey 9 as a made of square mesh screen having a mesh size Product, and here the final cost 13 Q5 selected to pass the largest particles or rocks dehigh due to the relative scarcity and the transp sired in the aggregate and such particles, as well tation req ir as all smaller ones, will therefore fall through gg figgg gifg g g gg fi fif g gg: 1 this deck and directly into the hopper 5 effectin ducing a percentage of chips as a concomitant of the first separatmn of the materialthe regular crushing operation and production, A sand screen or lower half deck I0 is arranged and at the same average cost as the regular agin the Screen below the pper end portion gregate used m such highway work Another of the deck 8 and is of fine trash to pass only ject is to provide a means for producing such Small nd particles and divert all larger parchips in a portable crushing plant and in any ticles off its lower end itno the hopper. Sand reasonable desired quantity relativetothe normal Passed y this c een "I is diverted by an adjustable wing or gate ll out from an end of the hopper to a side delivery sand conveyor l2.
The material rejected by the raw material receiving deck 8 is carried off the lower end thereof by an inclined chute I3 to a substantially centrally located primary jaw crusher ll of conventional form, and the material is therefore reduced to smaller size by action of this crusher. Such material then falls from the jaw crusher M to a conveyor l5 which carries it upwardly in a direction away from the hopper 5, to a point over the end of the frame A, the material being thenunit. This deck l8 has screens of two differentsizes, the upper end section l9 having mesh openings, for example one-half inch square to pass material of the maximum size desired for chips, and the lower end section 20 having openings of substantially the same size as those in the deck 8 to pass material of the maximum size required in the aggregate.
Material rejected by this deck I8 is caused to flow by gravity off the lower end and over an inclined chute 2| which leads to a conventional secondary roll crusher 22 located over the conveyor IS. The material is' thus further comminuted and is returned by conveyors l5 and Ho to the upper deck I8 for final separation. Properly correlated adjustments of the jaw and roll crushers l4 and 22, which adjustments may be made while the machine is in operation, will efiect the necessary'relative stage of reduction in each, to the point that all material recirculated to the screens will be finally passed out to the various delivery conveyors.
The chip size material passed by the upper end section 19 of the upper deck l8 iallsto an intermediate deck 23 in which is incorporated, below said section I9, a fines removing screen 24 of one-quarter inch mesh, for example, and which is thus adapted to pass all of the material of less size than the minimum required for the chips.
These fines drop to the raw material receiving deck 8 through which they pass into the hopper 5, as a component part of the delivered aggregate.
The material rejected by the screen 26, all of, chip size, is diverted by a bailie 25 through a side delivery port 26 to a chute 2'5 which leads down alongside the hopper 5 to a chips conveyor 28 delivering the material laterally, as shown.
The material passing through the lower section 20 of the upper deck l8 falls upon a blank section on platform 29 of the intermediate deck 23,, from which it is diverted laterally through of the material is caused to pass through more than one screen and all screens work constantly at maximum effectiveness.
- Under most circumstances the amount of chips required in the work is a small part of the total volumetric quantity output of the machine. This works as an advantage in that the production of the chips, as a by-product of the machine, will not remove too much of the component material of chip size required in the aggregate. Only oneport 26 and spout 21 are shown in the drawings, and the amount of chips delivered may be varied by use of a damper 32 in the spout as shown in Fig. 2 if so desired, the material, as this damper is opened, being diverted to fiow through a fork 27a of the spout back to the hopper through port 21b. However, it is obvious that delivery spouts for the chips may be used at each side of the screen unit if so desired.
The apparatus thus described permits the practice of a new method in the crushing and separation of stone and like material. This involves feeding the raw material onto a lower screen deck of a mesh size suitable to pass the largest particles required, screening out from beneath this lower deck a variable portion of the fine material or sand, conducting the material rejected by the lower deck to a primary jaw .crusher for initial crushing, returning such jected by the fines removing screen for use as after at least one crushing operation has taken to the maximum size required in the crushed product and carrying them by a by-pass means beneath the lower deck for mixing and delivery, conducting all particles rejected by the upper deck to a secondary .roll crusher for further crushing, and finally recirculatingthese crushed particles to the upper receiving deck. This method of crushing, screening, circulating and recirculating the material, aside from advantages such as the full use of all screens, balanced load on the respective crushers, and other features, also is of extreme advantage in the production of chips since the chip size material is screened out at substantially a mid point in the entire operation after at least one crushing operation has taken place. Thus material of chip size in the raw material will always be carried into the final aggregate mixture to retain the proper relative component sizes in the aggregate. Then place a separation is made to remove chip size material and deliver a variable quantity thereof for use. There are thus at all times two full screen decks producing finished material with a side ports 30 to by-pass ductsil leading the material to the hopper 5 below'the deck'B.
The general operation of the machine will be readily apparent from the foregoing, and it will be appreciated that the crushed material delivered to the hopper 5 through the various screens will be of the proper mixture required for highway construction and repair. The relative sand content may be varied as required by adjusting portion of one deck producing, if desired, the chip size product with separate delivery means. Referring particularly to Figs. 2 and 3, the
mechanical assembly of the machine will be described in more detail, the machine shown being one of practical construction and well adapted to illustrate my invention. The hopper 5 is supported on the frame A with suitable supporting parts and frame members. designated generally at 33. The various screen decks as heretofore described are arranged in a screen unit 34 which is placed in the frame over the hopper 5 and which is given a vibratory motion by any suitable and well known operating means (not shown). The jaw crusher l4 and roll crusher 22 are arranged in the assembly in substantially the positions shown, and are of the conventional conlaterally arranged to deliver the materials out to the side of the machine. Conveyor 9 is shown as being also of the conventional belt type and may be driven as indicated at 31 from driving parts of the machine, this conveyor of course being inclined upwardly from the'pit or other l2, and 28 for aggregate,.
feeding point. The return and recirculating conveyors l5 and 1511 are 'of the belt type. the first receiving material from both the jaw crusher I4, guided by the short pan 35, and the roll crusher 22, and delivering to .the lower end of'the second through a chute l5. Said chute is of course latuct rejected in this screening, screening the crushed product to remove therefrom material of chip size andsmaller, screening out said last mentioned fines from said chip size crushed material, and separately delivering the chip size material independently of the aggregate and chip size material resulting from .the first screening.
3. The method of crushing and screening rock to provide an ag regate and chips of substantially uniform size smaller than the maximum size of said aggregate, which comprises initially screening the rock to remove therefrom both the material of aggregate size and any material of chip size in said rock, crushing the rejected rock, screening the crushed rock to first remove material of chip size, and smaller, and then to remove material of larger size within the range of sizes required in the aggregate, screening out the lines from the crushed chip size material, separately to and with theaggregate and erally or angularly extended since the conveyors l5-I5u. operate alongside each other, and the delivery chute ii is similarly inclined to lead the material properly back to the screen unit as. Suitable supporting framework (A' in Fig. 1) is provided for outer ends of the conveyors l5-l5a and the chute i6. Inspection of upper working parts is provided for by provision of a platform 39, steps 45 and railings M in accordance with usual practice in such machines.
The sand gate H is adjustable from the side of the hopper by means of a lever 42 connected to the rock shaft as of said gate and working over a quadrant it as shown.
The screen unit 35 has spaced side panels or members :35 between which the screens or decks are mounted as shown in Fig. 2, and the chip delivery port 26 is formed in one of these side members with the spout 21 slidably embracing flanges 25a around said port in the manner clearly shown. The by-pass ducts 3| are also secured on these side members 55 over ports therein and are extended downwardly alongside the screen unit loosely into flared portions 30!: of the hopper to conduct all product-sized material from the upper deck to the hopper.
It is understood that suitable modifications may be maue in the structure as disclosed, pro-' vided such modifications come within the spirit and scope of the appended claims. Having now therefore fully illustrated and described my invention, what I claim to be new and desire to protect by Letters Patent is:
l. The method of crushing and separating rock material, which includes the steps of initially screening the material to remove particles of all sizes less than a selected maximum, crushing the material rejected in. this step of the method, screening the crushed material separately from the first screening step to remove a product of substantially uniform size less than the maximum resulting from said initial screening step, screening out the fines from said product and joining them with the smaller sized material of the first screening, and finally delivering said product separate from all other materials.
' 2. The method of crushing and screening a rock product to provide an aggregate and chips of a substantially uniform size smaller than the largest of said aggregate. which comprises screening the rock product to remove particles of both aggregate and chip size, crushing the rock proddelivering the chip size material secured after crushing, and conducting and mixing the. said fines and the said material of larger size directly chips secured by the initial screening 4. In a rock crushing and screening apparatus,
a conveyor for raw materials, a screen unit hav-' ing a ma n screen for receiving material from the conveyor and screening out materials of an aggregate size, means for crushing material rejected by the main screen, an u per screen arranged over the main screen, means for-returning crushed material to said upper screen, the said up r screen having openings in one portion for removing chips of a size smaller than the largest particles of the aggregate, and said upper screen also having openings in another portion for removing particles of size suitable for the use in the aggregate, an intermediate screen having openings in one portion for removing fines from the chips and having an imperforate por= tion for receiving the larger material of aggregate size from the upper screen, means for delivering the chip size material from the intermediate screen independently of the aggregate, and means for conducting the aggregate passed by the upper screen around the main screen for admixture with the aggregate passed by said main screen.
5. In a rock'crushing and screening apparatus, a conveyor for the raw material, a screen unit having three large and one small superimposed screens therein, the lower larger screen of said unit being adapted at one end to receive material from the conveyor and separate out particles of aggregate size, the small screen being disposed beneath said lower screen for removing a portion of the sand-like particles from the aggregate, means for crushing material rejected by the lower screen, means for returning said crushed material to the uppermost large screen of the screen unit, the said upper screenhaving openings in the portion receiving the crushed material for passing "screen, means for separately delivering chip-size material from the intermediate screen, and means for conducting aggregate size material from the intermediate screen for mixing with the material passed by the lower screen.
6. A rock crushing and screening apparatus for screening out material of aggregate size and a smaller material for use as chips, comprising a screen unit having a plurality of screens, means for conducting the rock first over one screen for removing an aggregate including material of chip size as a component part, means for crushing material rejected in the first screening, means for conducting said crushed materials over another screen, independently of the movement of material over said first mentioned screen, for first removing material of chip size and smaller and then removing larger material for use in the aggregate passed by the first screen, means for screening out the fines from the crushed chip size material and returning them to the first mentioned screen, means for separately delivering the crushed chip size material after the fines are removed therefrom, and means beneath the screen passing the crushed material larger than chip size for bypassing this material around the first mentioned screen and mixing it with the material of aggregate size.
7. A rock crushing and screening apparatus for separating an aggregate and a smaller chip size material from a raw rock material, comprising a screen unit having a plurality of screens, means for first conducting the raw material over one screen for separating out an aggregate which includes material oi chip size as a component part, means for c raw material rejected by the screen, means for conducting the crushed material over another ofvsaid screens for separating out material of chip size and smaller, means for screening out tliefines from said chip size material, means for separately delivering the chip size material after the fines are removed, means for returning the fines from the chip size material to the aforesaid aggregate, and means for screening out aggregate size material from the crushed material subsequent to removal of the chip size material therefrom.
8. The method of treating rock material to produce an aggregateof particles heterogeneously sized up to a predetermined maximum and a separate supply of particles of substantially uni-' 7 form size but smaller than such maximum, which gate size and delivering said uniformly sized particles separately, the balance of said crushed material of a size not greater than said predetermined maximum being returned to the material forming said aggregate mass to be comingled therewith.