US 2578180 A
Description (OCR text may contain errors)
1951 R. c. EDWARDS SCRUBBER WITH LINING AND PADDLES OF RUBBERY MATERIALS Filed Sept. 2, 1948 Patented Dec. 11, 1951 SCRUBBER WITH LINING AND PADDLES OF RUBBERY MATERIALS Ray 0. Edwards, Wauwatosa, Wis., assignor to Allis-Chalmers Manufacturing Company, Milwaukee, Wis., a corporation of Delaware Application September 2, 1948, Serial No. 47,428
2 Claims. (01. 241 102) This invention relates to devices for treating granular materials to efiect separation therefrom of adherent foreign substances without breaking down the granular material. More particularly it concerns an improved apparatus for scrubbing grains of material against one another under pressure to cause such separation.
Devices are known to the prior art in which granular materials are tumbled together to effect such separation of adherent substances therefrom, and there are some known devices in which pressure is exerted upon the granular material by relatively moving surfaces during treatment.
In metal foundry practice articles having interior surfaces are cast in molds having cores of sand mixed with various binders'which upon baking render the core strong and resistant to disintegration during the pouring operation. The binder is of such a character that it is carbonized or otherwise burned by the heat of the molten metal after pouring so that the core may be readily disintegrated for removal.
When the cores are removed, the sand grains are covered with a tenacious deposit of burned oils or other binders and cannot be reused to form strong cores unless reclaimed by some process which will remove this deposit.
Used sand has been reclaimed in the past by various processes, some involving machines for mulling the sand under certain conditions to cause a release of the grains from the tenacious deposits of foreign materials. It is desirable in this and other mulling operations for release of granular materials from tenacious surface deposits to avoid breaking down or comminution of the sand or other particles which are to be recovered as a product.
The present invention has as an object the creation of a novel apparatus for mulling granular materials which will effectively and efficiently release the grains from surface deposits.
It is a further object of this invention to provide a novel scrubberwhich may advantageously be used in reclamation of foundry sands and more particularly core sand. I
More specifically the invention concerns mulling the granular material to be treated in a-receptacle lined with a rubbery material, using a muller faced with a rubbery material, moving relative to, and biasedto move in a direction toward such lining ofrubbery material in a manner to -create pres' sure-against the material between the muller and lining surfaces.
Still more particularly, the invention is concerned with providing a continuously operated mulling machine having a stationary drum and a single continuously rotated muller rotor.
The invention having the above and still further objects and advantages which will become apparent from a reading hereof, may best be carried into practical effect as described herein with reference to the drawing, in which:
Fig. 1 is a vertical sectional view of a simple form of apparatus embodying certain features of the present invention.
Fig. 2 is a side view partially in vertical, longitudinal section of a preferred machine according to the present invention.
Fg. 3 is a cross section taken on line III-III of Fig. 2.
Like reference characters indicate the same or similar parts throughout the several views.
The simplest possible form of device embodying at least one feature of the present invention is illustrated in Fig. l of the drawing and consists of an opentopped, round container I with a rubber lining 2 constituting a work supporting surface. The container is mounted upon a base 3 from which a pedestal 4 projects upwardly extending over the open top of the container I.
Pedestal 4 rotatably supports a rotating shaft 6, driven by a motor I through bevel gears 8 and 9. At the lower end of shaft 6, near the bottom of container I, is a muller II having a pair of flexible muller arms I2 of rubbery material which are rotated with shaft 6 and have their ends thrust outwardly toward the lining 2 by centriff ugal force during rotation. The construction of the rotor II and arms I2 will be clear from a description of similar parts of the preferred embodiment described hereinbelow.
The preferred embodiment of the present invention is shown in Figs. 2 and 3 of the drawing. In this form a tubular container 2! is mounted on a framework 22, one end of which is pivoted at 23 to a suitablefoundation 23 and the other end of which is supported by an adjusting screw. arrangement 24 of suitable known construction. Pedestal bearings 26 and 21, at opposite ends of the frame 22, rotatably support a shaft 28 driven through a suitable power transmission mecha nism 29 by an electric motor 3| which may be mounted on frame 22.
Tubular container member 2! may be closed at its higher or feed end as by a cover 32 supporting a feed conveyor 33 and hopper 34 through which materials to be treated may be introduced into the feed end of the member 2 I. At the lower'end of member 2|, the discharge chute 36 is arranged to direct treated materials to a suitable point of use, in an obvious manner. The tubular member 2| is lined with a heavy coating 37 of resilient, tough, rubbery material forming a resilient work supporting surface.
Shaft 28 is made square between its journal portions, and is equipped with a series of pairs of muller arms each pair displaced by .ninety degrees from the-adjacent pair on either side. "The muller arms are each composed, for example, of a plate 38 welded to shaft 28 and projecting to one side, and a flap 39 of thick rubbery material secured to the plate 38 and extending outwardly tangent to the shaft. It will be seen from the drawing that the muller arm flaps 39 are .of such length radially of the shaft that the tips of a pair of such flaps would normallyextend in opposite directions to a diameter exceeding the internal diameter of the tubular member 2i or its lining 31, in which they are to be used, so that when inserted in the tubular member, the flaps must :be .fiexed in a radial plane. Rotation 'of shaftlZS in .the direction of the arrow 4| inFig. 3 will 'cause the flaps 39 to flex in asenseoppos'ite the direction of rotation, their tips dragging in frictional engagement with the lining 3! and being thrust outwardly by centrifugal force. The flaps of each pair-of muller arms will, "of course, extend in opposite directions relative to the shaft 28 to balance each'other.
The muller arms of the device of Fig. 1 are of construction similarto those of Figs. 2 and S,'the arms I 2 corresponding to'fiaps 39.
In order to provide for development of the desired forces, each flap 39 (or arm [2) maybe provided with a weight bar 42 suitably secured to the rearward side of the flap tip. Rotation of the shaft 28 will cause centrifugal force to be exerted on the weight bars 52 increasing-the pressure between the flap tips and the rubber lining 31 (2) for reasons set forth hereinafter.
Operation of the device of Fig. 1 is of course, quite simple. -A charge of materialto be treated is inserted in the open top of container I, the rotor is turned, and arms i-2 fly out under the influence of centrifugal force, agitating the material in container 1 and forcing the particles to move against each other. Particles caught between the tips of arms [2 and the surface of lining 2 will be mulled under pressure, and tenacious surface deposits will be loosened therefrom by impact and attrition between the grains Action of the rubbery surfaces themselves will of course not cause any substantial degradation or comminution of materials and the net result will be .a loosening and removal of surface deposits from the grainsunder treatment.
The device of Figs. 2 and 3 is operated by rotating shaft 28 in the direction shown by the arrow in Fig. 3 and supplying material, such as used core sand, ore particles with tenacious surface deposits, or other granular material to be treated, to the hopper M, whence it is conveyed by feed conveyer 33 to the interior'of tubular member 21 near its higher end. The first pair of flaps 39 rotating in an inclined plane will strike the material, agitating the same and scrubbing the particles against each other under pressure between the rubbery surfaces of the tips of flaps 39 and lining 3?, and since the material particles will be moved by the flaps in an inclined plane. and will fall under the influence of gravity when ..not being so moved, the particles will be gradually advanced toward the lower end of the .drum 2| by the action of the flaps or paddles and gravity, and will ultimately be discharged at chute 36.
Continuous feed of material at 34 will result in continuous operation of the apparatus upon a stream of material in container member 2|. The rate of feed and discharge will be de pendent upon the speed of operation of shaft 28, the incline of the container 2 i, and the flow characteristics of the material being treated; and
these factors will be chosen in practice to give a suitable discharge product.
It will be understood that particles of material being struck by the flaps 39 (12) will be driven outwardly toward lining 31 (2) where they will be acted upon by rubbing against other particles under pressure resulting from centrifugal forces,
"augmented by the forces of flying weight bars '42. The product will be a mixture of grains of material and finely reduced and loosened particles of the surface deposits which may readily be separated from the product by known classification methods, the desired product being col- 'lected in a'compara'tively'pure state.
The apparatusde'scribed hereinabove has been found, in actual tests on used industrial core sand, and other foundry sands, to have a very beneficial effect and to assist greatly in the task of reconditioning such materials for reuse.
It will be understood that the apparatus particularly described and illustrated is by way of example only, and that the invention includes such'modifications andequivalents as may readily occur to persons skilled in theart to which it appertains within the scope of the appended claims.
It is claimed and desired to secure by Letters Patent:
'1. Apparatus for continuously mulling granular material, comprising: a generally cylindrical container havinga resilient liner providing a depressible work supporting surface; means for depositing said granular material on said work sup porting surface at one endthereof; muller means rotatable within said container for rubbing said granular material against said work supporting surface and conveying said material longitudinally through said container; -said muller means having at least one set of flexible, radially extending, circumferentially spaced flaps extending toward and engaging with said work supporting surface, each of said flaps being of a sufficient length that its extremity lies flat on said work supporting surface during rotation of said muller means; weight means associated with said extremities 'of said flaps to cause said extremities to depress successive portions of said work supporting surface, the restoration of the depressed portions of said work supporting surface causing said material to be thrown from said depressed portions; and means for rotating said muller means relative to said container.
2. Apparatus for continuously mulling granular material, comprising: a generally cylindrical container having a resilient'liner providing-a depressible 'worksupporting surface; means for depositing said granular'material on said work supporting surface at one end thereof; muller means rotatable within said container for rubbing said granular material against said work supporting surface and conveying said material longitudinally through said container; means for inclining said container to obtain in cooperation with said mu'llerimeans an optimum rate of feed and discharge for the kind of material to be mulled;
said muller means having at least one set of 'flex ibl'e, radially extending, circumferentially spaced flaps extending toward and engaging with said a 5 work supporting surface, each of said flaps being of a sufiicient length that its extremity lies flat on said work supporting surface during rotation of said muller means; weight means associated with said extremities of said flaps to cause said extremities to depress successive portions of said work supporting surface, the restoration of the depressed portions of said work supporting surface causing said material to be thrown from said depressed portions; and means for rotating said muller means relative to said container.
RAY C. EDWARDS.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 36,541 Trimmer Sept. 23, 1862 20 207,294 Moeneh Aug. 20, 1878 Number Name Date 1,700,713 Campion Jan. 29, 1929 1,916,858 Earle July 4, 1933 1,933,278 Piper Oct. 31, 1933 2,044,757 Cross June 16, 1936 2,115,314 McEarlean Apr. 26, 1938 2,173,975 Lyons Sept. 26, 1939 2,306,422 Beardsley Dec. 29, 1942 2,493,049 Weinig Jan. 3, 1950 FOREIGN PATENTS Number Country Date 322 Great Britain of 1852 3,118 Great Britain of 1864 OTHER REFERENCES New Methods of Cleaning Glass Sands," by Dasher and Ralston. Pages 187-195 of The Bulletin of the American Ceramic Society, June 1941. Pages 187-189 only pertinent to this application.