US2835941A

US2835941A - Apparatus for recovering, reconditioning and reusing the used core sand employed in casting

Info

Publication number: US2835941A
Application number: US614927A
Authority: US
Inventors: Muller Karl
Original assignee: Steinlein & Kunze GmbH
Current assignee: Steinlein & Kunze GmbH
Priority date: 1956-04-18
Filing date: 1956-10-09
Publication date: 1958-05-27
Anticipated expiration: 1975-05-27
Also published as: FR1155273A

Description

K. MULLER 2,835,941 RING, RECONDITIONING AND REUSING Filed Oct. 9, 1956 THE USED CORE SAND EMPLOYED IN CASTING May 27, 1958 APPARATUS FOR RECOVE INVENTOR Karl Mal/er United rates Patent APPARATUS FOR RECOVERING, RECONDITION ING AND REUSING THE USED CORE SAND EMPLOYED IN CASTING Karl Miiller, Koblenz-Metternich, Germany, assignor to Steinlein & Kunze G. in. b. H., Koblenz-Metternieh, Germany, a firm Application October 9, 1956, Serial No. 614,927 Claims priority, application Germany April 18, 1956 1 Claim. (Cl. 22--89) This invention relates to casting, and more particularly to an apparatus for recovering, reconditioning and reusing the used core sand employed in casting.

As is known, a sand mold employed in foundry practice is useless after a casting has been made and is broken up and thrown on a rubbish heap. In this way the loss is very considerable in the course of time, particularly as regards the core sand as well as the binding material and other valuable residues adhering thereto.

The object of the present invention is to provide an apparatus for recovering these sand residues and the valuable components adhering thereto and to render them fit for further use after reconditioning the molding sand and particularly the core sand, in which the pieces of core sand are broken up in a rotary drum having an inner shell provided with a plurality of slots and an outer shell in spaced relation to said inner shell and constructed as a sieve, with the aid of large metal balls, causing resultant sand grains to drop in continuous succession through the outer drum shell having a desired mesh width, removing by suction, during this operation, the dust from the drum and out of a sand catching receptacle, and periodically removing core pins and other solid residues from the drum in known reverse movement.

The apparatus for carrying out this process comprises a rotary drum having an inner shell and an outer shell of diiferent diameters, a number of thick metal balls in said inner drum shell, a hollow shaft on one side of the drum, a charging hopper extending from said hollow shaft, residue discharge means on the opposite side of the drum, the inner drum shell being provided with slots and the outer drum shell constructed as a sieve with a mesh width determined by the grain size of the sand, a slotted funnel chute with a sand catching receptacle provided underneath the drum, and exhausters arranged above said drum and on said slotted funnel chute.

By the frictional process in the inner, slotted drum shell the core sand parts fed therein are quickly broken up without the individual sand grains being ground, and they drop immediately through the slots on to the second, outer drum shell constructed as a sieve having a mesh width corresponding to the size of grain of the core sand being treated. The sifted grains drop through the slotted funnel chute into the catching receptacle, the dust whirled up in the process being sucked off by exhausters.

According to another feature the valuable binding material and other residues adhering to the recovered sand grains are individually recovered by suitable solvents and again used for preparing the molding and core sand, for binding and stiffening the cleansed sand grains or the initial material in question.

The invention enables the core sand pieces and the sand grains forming these, to be fed in quick succession in pure condition and free from dust for use again and, moreover, by the recovery of the binding material adhering to these sand grains, about 50% of the expensive treatment material to be saved and rendered available for preparing the core sand once more. For example, diluted water Patented May 27, 1958 glass or other suitable chemicals, the cost of procuring which is in no proportion to the recovered expensive binding and stiffening agents, are used as solvents.

An apparatus for carrying out the process is illustrated by way of example in longitudinal section in the only figure of the accompanying drawing.

A rotary drum driven by a motor 1 consists of an inner drum shell 2 provided with slots and a second, outer shell 3 mounted at a distance from the shell 2 and constructed as a sieve. The drum shell 2 is of cylindrical cross section or flattened or constructed like a honeycomb and accommodates several large metal balls 4. The material to be prepared, i. e. the core sand pieces, are fed by means of a lateral hopper 5 through a hollow shaft 6 into the drum. A slotted funnel-shaped chute 7 extends from the shell 3 underneath the drum and is connected up with an exhauster, not shown in the drawing, for the purpose of drawing off the dust produced. Similarly, an exhauster is connected to a short pipe 8 mounted above the drum for removing the dust forming in the drum.

On the left side of the drum in the drawing there is a gap 9 between the face of the drum and its casing, which gap, through the intermediary of suitably arranged guide plates, communicates with a hollow shaft in which carries a conveyor worm 11. This arrangement serves for removing the residues, such as core pins and the like, which remain on the sieve shell 3, and on this account the direction of rotation and the speed of rotation of the machine is periodically changed by the motor with change of pole connections, with the result that the said residues pass out through the hollow shaft 10.

The form of the apparatus described constitutes in eflect a preferred embodiment of the invention and it is to be understood that the invention is not limited to this precise form of apparatus, and that changes may be made without departing from the scope of the invention which is defined in the appended claim.

I claim:

In apparatus for recovering used core sand in its original granular state, comprising a rotary drum including circumposed inner and outer shells, a plurality of loosely disposed impact elements in said inner shell insuflicient in number to grind the core sand disposed therein, means for introducing used sand cores axially of said inner shell, a discharge chute depending beneath said outer shell for conducting separated core sand therefrom, said inner shell including a plurality of longitudinally disposed slotted portions therethrough through which used core sand may pass and defining a friction surface on the inner periphery of said inner shell, said slotted portions and impact elements serving to only break up used sand cores, said outer shell comprising an annular sieve surrounding said inner shell and having a mesh size equal to the original grain size of the core sand being separated, said discharge chute including an intermediate bafiie portion for impeding the fall of the separated core sand, and suction means communicating peripherally of said outer shell and at the bafile portion of said chute for drawing oif material mixed with the core sand of a size less than that of the separated core sand.

References Cited in the file of this patent UNITED STATES PATENTS