US3312403A

US3312403A - Machine and process for reclaiming foundry sand

Info

Publication number: US3312403A
Application number: US422820A
Authority: US
Inventors: Zifferer Lothar Robert
Original assignee: Individual
Current assignee: Individual
Priority date: 1964-12-31
Filing date: 1964-12-31
Publication date: 1967-04-04
Anticipated expiration: 1984-04-04

Description

April 4, 1967 R. ZIFFERER 3,312,403

MACHINE AND PROCESS FOR RECLAIMING FOUNDRY SAND Filed Dec. 31, 1964 a Sheets-Sheet 1 38 40 INVENTOR.

10mm Rosier ZF/fkfk F523,; BY J @QQQW 45/ MACHINE AND PROCESS FOR RECLAIMING FOUNDRY SAND Filed Dec. 31, 1964 April 4, 1967 1.. R; ZIFFERER INVENTOR. Larvae Ross/er Z/rrz/wz 3 Sheets-Sheet 2 ATTOENiY April 4, 1967 R. ZIFFERER MACHINE AND PROCESS FOR RECLAIMI-NG FOUNDRY SAND Filed Dec. 51, 1964 3 Sheets-Sheet 5 f R E RE w v 8 mm a m NH /w 7 E//../ 1A W 1W v Z,

United States l atent O 3,312,403 MACHINE AND PROCESS FUR RECLAIMING FDUNDRY SAND Lothar Robert Zifferer, RD. 3, Glen Rock, Pa. 17327 Filed Dec. 31, 1964, Ser. No. 422,820 22 Claims. (Cl. 24124) This invention pertains to a machine and process rfior reclaiming foundry sand and, more particularly, to reclaiming foundry sand from broken pieces and. particles of molds made from bonded sand following the use thereof as cores and mold forms in foundry operations. Usually, sand which is used in bonded type cores and mold forms is not reusable to make additional cores and mold forms until the previously used bonding material has been removed from the grains of sand so as to clean them and prepare the for reuse. The value of some types of sand used in foundry operation does not warrant reclaiming .the same, whereby the present invention primarily is intended for use in regard to reclaiming that type of sand having salvageable value either due to the worth of the sand or the inconvenience of replacing it.

The principal object of the invention is to recondition used ibonded sand of the type referred to by subjecting the same to impact either against a relatively stationary or movable impact means, or both.

Another object of the invention is to provide such impact means with a yieldable, rubber-like surface so as to induce rebonding of the pieces and particles, as well as some grains of sand therefrom, into the path of oncoming pieces and particles or grains so as to effect not only separation of the connected grains of sand from the used bonding material, but also scour the bonding material from the grains of sand by such impact, as Well as abrasive contact with adjacent pieces and particles of sand and bonding material.

A further object of the invention is to initially reduce the bnoken pieces, lumps and particles of used cores and mold forms into a predetermined maximumsize of pieces or particles thereof which are relatively small and thereby facilitate the separation and scouring of the grains of sand by such impact procedures and mechanism comprising the essentials of the present invention, such initial reduction preferably resulting from a grinding operation.

Another object of the invention is to provide mechanism by which the cleaned sand particles are separated from the waste, powdered bonding material and, as a corollary to this objective, the invention also includes means and procedures for effecting a recycle of the material, especially upon the completion of the introduction of the initial portion of a batch of used dumps or pieces and particles of cores and/ or mold forms into the reduction and scouring machines, whereby relatively rapid reduction and scouring of the material occurs due to recycling to produce clean sand grains in sufiicient proportion that separation thereof from the waste bonding material should occur, whereupon operation of certain elements of the machine effects progressive removal of the cleaned sand grains from the machine, simultaneously with the removal of waste, powdered bonding material.

A still further object of the invention is to effect substantially constant removal of powdered, waste bonding material, by suction, from the interior of the securing chamber of the machine as said waste material occurs in the machine and is more or less suspended in the atmosphere therein, whereby the machine is not unduly burdened with retention of such powdered waste bonding material after the same has been reduced to such size that it may be removed by suction.

' Ancillary to the foregoing object, it is a still further object of the invention :to position the inlet of the suction means within the scouring chamber inter-mediately of the upper grinding zone or compartment and the lower scouring zone of the machine.

Still another object of the invention is to provide selective recycling of the material being treated for Stratification of cleaned sand from the portion of the charge of material which should be recycled, whereby used lumps, pieces and particles of bonded sand-type cores and mold forms may be continuously fed to the machine While cleaned sand grains are continuously removed therefrom together with simultaneous, continuous removal of powdered waste bonding material Details of the foregoing objects and of the invention, as well as other objects thereof, are set forth in the following specification and illustrated in the accompanying drawings comprising a part thereof.

In the drawings:

FIG. 1 is a vertical elevation of an exemplary machine for producing the process and embodying the mechanical principles of the invention for reclaiming cleaned sand grains from used mold pieces and particles made from bonded sand and employed as cores and mold forms in foundry operations.

FIG. 2 is an enlarged, fragmentary vertical elevation of the grinding and scouring portions of the machine shown in FIG. 1.

FIG. 3 is a top plan view of the grinding and scouring unit of the machine shown in FIG. 2, with the addition of an exemplary motor to drive the same, part of the elements being broken away to illustrate details of certain portions of the machine with clarity.

FIG. 4 is a fragmentary vertical elevation of a portion of the grinding machanism illustrated in FIG. 2 and showing an exemplary concept of the discharge of reduced material from said mechanism.

FIG. 5 is a fragmentary vertical elevation of the discharge portion of the scouring portion of the unit of the.

away, illustrating segregating mechanism used in con-.

junction with recyling the material being treated and removing cleaned sand grains FIG. 8 is a fragmentary perspective view of the mechanism shown in FIG. 7, but illustrated on a smaller scale than employed therein to depict the discharge of clean ly phenolics, silicates, such as sodium silicate or water glass, and clay of different types.

After cores and mold forms have been used to cast various types of metal forms therein, the mold and casting usually is subjected to a shake-out machine which operates to break the molds and cores into various sizes of lumps, pieces and particles, and thereby separates the same from the completed casting. The molding operation very largely causes changes in the bonding material employed to hold the grains of sand in desired shapes of cores and-mold forms, whereby it usually is desirable to separate the bonding material from the sand grains substantially after each use thereof, and mix new bonding material with the reclaimed or cleaned sand grains, as well as adding new make-up sand to replace losses incurred in the shake-out operations, for example, such as that which clinks to the castings. Then new shapes of cores and variousmold forms are formed therefrom.

The present invention relates to an improved process and embodiments of a machine for separating the bonding material of the principal categories referred to above from the sand particles in the l-umps, pieces and particles of used cores and mold forms resulting from the preceding molding operation in a foundry, so as to cleanse the sand particles thereof to a sufficient degree to enable the same to be used in new forms of cores and molds after new bonding material has been mixed therewith in accordance with customary procedures.

Essentially, the process and machine embodiments comprising the improvements afforded by the present invention include a reduction compartment into which the lumps, pieces and particles of disintegrated cores and mold forms are .introduced to reduce the same to a predetermined maximum size, whereupon the reduced material is introduced into a scouring compartment 12, there also being located between said two compartments a vacuumtype dust removal system 14, the inlet of which is preferably located intermediately of said compartment so as to impose a minimum of burden upon the treatment operations as the result of any undue accumulation of dust, such as abraded bonding material, being entrained in the atmosphere within said compartments of the machine.

Referring to FIG. 1, the socalled raw material, comprising the used bonded sand in the form of broken pieces of cores and mold forms is introduced by any suitable means, such as a conveyor 16, into a relatively large funnel-like hopper 18, which is mounted above the upper end of a preferably cylindrical container comprising the principal unit of the machine or system embodying the present invention. The upper portion of the container 20 forms the reduction compartment 10, while the lower portion thereof comprises the scouring compartment 12, the latter having a substantially horizontal bottom 22.

Extending across the upper end of the container 20 is a substantially horizontal top 24 having a central opening 26 therein. Depending fromthe periphery of the opening 26 is a cylindrical shell or collar defining the confines of the reduction compartment 10. Supported by the inner surface of the collar 28 and depending from the lower edge thereof a predetermined distance is a relatively thick, heavy and durable rubber-like liner 30. Said liner is cylindrical and is clamped to the collar 28 by means of a plurality of circumferentially spaced, vertical wear-resisting metal bars 32 for purposes to be described. Said bars may be clamped into operative positions relative to the liner by any means, such as bolts 34.

As best seen from FIG. 1, the container 20 is supported by a pedestal assembly 34 from which a large, heavy-duty bearing 36 extends vertically upward through the bottom 22 of. container 20 and into the lower portion of scouring compartment :12, as best seen in FIG. 2. The bottom 22 may be secured, such as by welding, at 38 to the bearing 36 for support of the container 20 thereby. Rotatable within bearing 36 is a vertical shaft 40 to which a vertical collar 42 is fixed, by any suitable means, such as a key and keyway, set screw or the like, so as to be rotatable with said shaft. Suitable cap means 34 surmount the upper end of bearing 36 so as to minimize the ingress of dust and the like into the bearing from the scouring compartment 12.

Fixed to the lower end of collar 42 is a preferably circular disc 46 comprising rotatable means disposed within the scouring compartment 12 and to which a plurality of radially extending impellers 48 preferably are connected so as to be radially adjustable, such as by means of slots 50 and bolts 5-2, best shown in FIG. 3. The impellers 58 terminate outwardly in cup-like scoops 54 disposed in vertically spaced relationship to the bottom 22 of container 20, for purposes to be described.

The upper end of collar 42 terminates in a horizontal flange 56 which is disc-like and substantially wider than collar 42 for purposes of supporting an abrading, relatively thick and circular grinding wheel 58, which is the principal active element within the reduction compartment 10. The upper surface of grinding wheel 58 is spaced a predetermined distance below the lower edge of the liner 36 for purposes of providing a discharge slot 60, best shown in FIGS. 2 and 4. The height of said slot is determined by the adjustable position of the liner 30 with respect to the collar 28 through the means of the clamping bars 32 and the slot 60 is for purposes of controlling the maximum size of the small pieces and particles 62 of material resulting from the reduction operation occuring within compartment 10. Said pieces and particles comprise interconnected grains of sand still bonded together, as well as some individual grains thereof more or less coated with bonding material, as well as some abraded bonding material more or less in powdered form.

As the raw material referred to above is conveyed to the hopper 18 for introduction through opening 26 into the reduction compartment 10, the rotation of the grinding wheel 58 tends to somewhat throw the material toward the periphery of compartment 10 so that it engages the abra-ison-resistant bars 32 and the inner surface of liner 3%, the bars 32, as best seen from FIG. 3, being circumferentially spaced but sufficiently close that they tend to somewhat hold the material against any excessive movement with the grinding wheel 58, whereby rapid abrasion and disintegration of at least the larger lumps and pieces of the material occurs until they are reduced to such size that they can pass through the slot 69, as illustrated diagrammatically in FIG. 4.

In view of the yieldable nature of the liner 30, the height of the slot 60 can be maintained reasonably well over substantial periods of time, but, after wear of the lower edge of the liner 30 has occurred to the extent that adjustment of the liner is required, such adjustment can be effected rather quickly and readily by loosening the bolts 34, lowering the liner, and then reclamping the liner in the newly adjusted position. The grinding wheel 58 is rather simply connected to the flange 56 so as to be rotatable with the shaft 40 by a simple clamping plate 64- which is held against wheel 58 by a washer 66 and a bolt having a transversely extending head 68 thereon. Said head 68 not only serves as ready means to rotate the bolt but also acts to fling lumps and pieces of the raw material toward the periphery of reduction compartment 10.

Disintegration of the partially reduced material into individual grains of sand, as well as abrading the bonding material from the individual grains of sand so as to clean the sand by removing said bonding material to an acceptable degree, primarily occurs within the scouring compartment 12. In addition to the rotatable impellers 48, which are the principal milling elements in said compartment, another very essential feature of said scouring compartment comprises a plurality of radially extending stationary impact members 70. These are fixed to the inner surfaces of the shell comprising container 20, the radial dimension of said impact members preferably being substantially equal to the space between the periphery of disc 46- and the inner surf-ace of the cylindrical inner liner 72, which is fixed suitably to the inner surface of the container 20. Said liner may be formed of material similar to that from which the liner 30 is formed and the thickness thereof likewise may be similar. However, the liner 72 extends substantially from the bottom 22 upwardly a substantial distance, terminating preferably just a little below the level of the grinding wheel 58, as clearly shown in FIG. 2. Said liner, being of a yieldable, rubber-like nature, saves the inner surface of the container 20 from any undue abrasion and wear.

Not only for purposes of preventing undue abrasion of the stationary impact members 70, which preferably are formed of suitable metal, but also to afford additional impact action by providing a rebounding effect, the impact members 70 are covered with a substantially fiat sleeve of yieldable, rubber-like material 74, which, if desired, may be formed from material similar to that from which the

liners

30 and 72 are formed. It will be seen, especially from FIG. 2, that the members 70, being formed from metallic plate material of suitable thickness, have an appreciable vertical dimension so as to provide impact areas of substantial extent upon the faces of the flat sleeve-like yieldable covering member 74 supported by the impact members 70 and forming a part thereof.

From the foregoing, it will be seen that the vertical shaft 40 commonly supports and rotates the grinding wheel 58 and the member 46 which supports the impellers 48 in the lower portion of the scouring compartment 12. As material is discharged through the slot 60 in a more or less steady stream descending from the reduction compartment into the scouring compartment 12, there will be a certain build-up of a body of said material upon the bottom 22 of the scouring compartment. Also, sediment material will be engaged by the impellers 48 as it falls.

The feed of the material to the scouring compartment 12, as well as removal thereof from said compartment, by means to be described, is such that a build-up of the material upon the bottom 22 will not occur to a level higher than the disc 46 and preferably slightly below the same. The scoops 54 of the impellers 48 preferably are shaped in relation to their direction of rotation, as indicated by the arrow in FIG. 3, so that they somewhat plow the material gathered upon the bottom 22 and, as shown somewhat diagrammatically in FIG. 6-, fling the material upwardly gainst the yieldable covering of the stationary impact members 70, impinging the material thereagainst to cause disintegration of the particles and small pieces thereof as well as flaking off and otherwise disintegrating the used bonding material covering the sand grains.

In addition to the foregoing, the sharp impact of the material against the yieldable surface of members 70 afforded by the covering sleeve 74 causes a rebounding of the material away from such yieldable surfaces and, while moving in rebounding direction, collision of said particles and pieces with oncoming particles and pieces occurs, whereby a certain amount of disintegration of the pieces and particles into individual grains, as well as flaking and chipping of the bonding material therefrom, likewise occurs from such supplemental rebounding action. In addition, of course, the yieldable covering 74 on the members 70 results in a minimum of wear to both the covering 74 as well as the impact members 70.

To afford an appreciation of the force with which the material 62 is impinged against the yieldable coverings 74 of the stationary impact members, it is preferred that the scoops 54 move at a peripheral speed of between substantially 2,000 and 5,000 feet per minute, depending upon the speed at which the reclaiming of the sand is desired, as well as the nature of the bonding material employed in the cores and mold forms from which the sand is being reclaimed. It can be appreciated that the force of impact of the material 62 against the yieldable coverings 74 is very substantial, and likewise the rebounding speed of the material from the yieldable coverings is comparable, as when colliding with oncoming material parti cles.

Not only do the scoops 54 of the impellers deflect the material 62 upwardly against the stationary impact members 70 and their yieldable coverings, but said scoops also constantly tend to move at least part of the material circumferentially around the bottom 22, especially adjacent the periphery thereof, as well as around the lower portion of the liner 72. Extending radially from the lower portion of the container 20 adjacent the lower portion of the scouring compartment 12 is a substantially horizontal discharge duct 76, shown best in FIGS. 1 and 2, the same having an appropriate discharge control means therein specifically illustrated as a vertically movable gate valve 7 8.

Exemplary operation of said discharge means is illustrated somewhat diagrammatically in FIG. 5. From this figure, it will be seen that the gate valve has an opening and, depending upon the degree of eccentricity of the opening 80 in the gate valve with respect to the discharge duct 76, the passage of material from the scouring compartment 12 through the duct 76 will be regulated as desired, especially in relation to the rate of feed of the raw material to the grinding compartment 10, whereby substantially continual operation of the machine is possible.

In accordance with the preferred, contemplated opera tion of the machine described hereinabove, the material undergoing treatment in the scouring compartment 12 is continuously recycled, while a limited portion thereof is continuously with-drawn as substantially cleaned sand, such withdrawal being effected by mechanism described hereinafter. Preferably, the recycling continues without withdrawal of the clean sand when reclaiming operations are initiated in the machine, such recycling occurring until a suitable percentage of cleaned sand is present in the material, whereby withdrawal of the same should be instituted. Further in accordance with the preferred operation of the machine, the ratio of recycling to withdrawal is approximately of the order of about 50:1. The withdrawal of cleaned sand, and removal of waste, powdered bonding material, should be substantially equal to the rate of feed and weight of the raw material to be fed to the machine for reclaiming of the sand therefrom.

Referring to FIG. 1 again, it will be seen that exemplary elevating apparatus 82 is shown, which may be one of a number of different types. As seen from FIG. 7, one exemplary type of elevating apparatus comprises a flexible elevator member 84, which may be either of a belt or chain nature, to which a plurality of spaced scoops 86 are connected. Said scoops pass over the upper axis 88 of the flexible member 84 so that the scoops dump, somewhat by centrifugal force, at the top of the elevating apparatus, which preferably is enclosed within a housing. This not only minimizes the occurrence of dust in the atmosphere but also permits the removal of some of the powdered waste bonding material, as well as disintegrated, powdered sand grains, by means of vacuum applied to the upper portion 90 through the medium of a vacuum conduit 92, which, in the specific illustration in FIG. 1, comprises a branch of a main vacuum conduit 94 leading into a dust collector 96.

Vacuum is created in the dust collector by means of a blower 98, the inlet of which is connected by conduit to the dust collector 96, thereby inducing suction therein. It will be understood that the dust collector 96 is of the vacuum-vortex type which separates the dust from the air in which it is entrained while passing through vacuum conduit 94, the dust being collected in a suitable receptacle, such as tank 102 communicating with the bottom of dust collector 96, as best shown in FIG. 1.

Another branch vacuum conduit 104 extends from the main vacuum conduit 94 to the dust removal system 14 comprising a duct 106 extending substantially radially into the container 20 and terminating in a relatively short, substantially vertical cylinder 108 comprising the inlet of the vacuum dust removal system 14. It will be seen that the inlet 108 is substantially intermediately between the grinding wheel 58 and the radial impellers 48 within the scouring compartment 12. Further, the diameter of the cylinder 1028 is appreciably greater than the collar 42,whereby there is ample annular inlet space between said collar and the cylinder 108.

Thus, when negative pressure is imposed upon the duct .106 by means of the vacuum produced by blower 93, as

described above in relation to the various intervening ducts and conduits, dust and finely divided material comprising disintegrated bonding material and possibly a limited amount of disintegrated powdered sand grains which are entrained within the atmosphere in the securing co mpartment 12 will be continually removed from said scouring compartment by said dust removal system 14. Such arrangement will result in the disintegration of the small pieces and particles of material 62 occurring without impedance by any appreciable amount of such waste dust material being in the atmosphere within the scouring compartment 12, whereby the efiiciency of operation of the machine is enhanced.

The rotatable scoops 54 and the grinding wheel 58 are rotated, in unison, by drive shaft 49, which is driven by any conventional type of drive means, such as an electric motor 110 of appropriate horse-power rating, see FIG. 3, which is mounted adjacent one side of the pedestal assembly 34. A preferably multiple drive pulley 112 is connected to the motor shaft and multiple V-belts 114, or the like, extend around the same and a much larger diameter multiple sheave 116 which accommodates a similar number of belts as pulley 112 and is fixedly connected to the lower end of drive shaft The motor 110 preferably is of a variable speed type in order to drive particularly the rotatable scoops 54 at a desired linear speed in accordance. with the type of material being treated, especially the bonding material upon the grains of sand, and the speed at which the cleaning of the sand is desired.

As mentioned above, the sand-scouring system described in the foregoing and illustrated in the drawingsincludes means to recycle the material while being treated, the vast majority of the mass of the material being continuously recycled while only a relatively small proportion of the material is substantially continuously removed from the system as cleaned product sand. One of the essential elements of the system to accomplish such recycling is the means for transferring the product which passes through discharge duct 76 to the inlet receptacle 118 extending upward from the top 24, as best shown in FIGS. 2 and 3. The inlet receptacle communicates with an inlet opening 120 formed in the top 24 of container 20, but itwill be noted from FIG. 2 that said opening is radially offset from the reduction compartment 10, whereby as material is withdrawn from discharge duct 76 and is reintroduced to the container 20 through the inlet opening 120, the material will fall into the scouring compartment 12 and completely by-pass the reduction compart ment 10.

Although the drawings specifically illustrate elevating apparatus 82 in the form of a flexible conveyor 84 having scoops 86, it is to be understood that other types of elevating means may be employed, including, for example, a rotatable drum operating upon a centrifugal principle and having scoops extending into the upper part thereof which plow into the material to remove it from the elevating drum. Still other well-known types may be used. Ac-

cordingly, the specifically illustrated elevating means are not to be regarded as restrictive but merely as illustrative of one type capable of recycling the material as described above.

Such recycling of the material, and especially the reintroduction thereof to the scouring compartment 12, is and important aspect of the present invention in that it permits the failing materialto be intersected by additional impact means of a movable nature, as distinguished from the stationary impactmembers 7%. For convenience and economy, as well as effective action, it has been found that additional movable impact means can be provided 'in the form of radially extending rods or shafts 122, at

circumferentially spaced locations around the periphery of the grinding wheel 58 or any shell or frame within which it is contained, said rods or shafts 122 being rigidly fixed to the periphery thereof. A substantial number of movable impact members 122 are provided, as can best be seen from FIG. 3. A total of eight are specifically illustrated, but this number is not to be regarded as restrictive since more or loss within reasonable bounds can be employed.

As in regard to the stationary impact members 70, and for the same purpose, the movable impact members 122 preferably are covered with tubes or sleeves 124 of yieldable, rubber-like material, to not only minimize wear upon the members 122, but also to induce a rebounding effect upon the material falling through the opening 120 during the recycling thereof, thereby increasing the final reduction of the material into individual sand grain condition and also aiding in scouring the grains to remove the bonding material from the exterior thereof. This additional reduction and scouring augments the similar function of the stationary impact members 70. Accordingly, it will be seen that the machine is provided with both stationary and movable impact members which supplement each other, in a compact arrangement and effectively cooperate to produce a desirable, common result.

It will be seen from FIG. 3 particularly that the inlet receptacle 118 is rectangular in plan view for purposes of affording an arcuate configuration, in plan view, to the inlet opening 120, whereby the material reintroduced into the scouring compartment can fall through an area of substantial transverse extent. This not only provides for the accommodation of appreciable quantities of material while being recycled, but also permits the inclusion of mechanism by which the aforementioned, relatively minor percentage of cleaned, product sand grains may be removed, especially after the initial recycling of the material at the commencement of operation of a new batch, for example, has occurred without withdrawing any product until a desired percentage of finished, clean sand grains has been produced for removal from the system. Details of the exemplary mechanism for removing the cleaned, sand grains are as follows.

With reference particularly to FIGS. 7 and 8, it will be seen that the exemplary elevating apparatus 82, which specifically includes scoops 36, is driven at a linear speed capable of causing at least a certain amount of centrifugal discharge of the material from the scoops as they pass over the upper axis 88 of the flexible conveyor unit, as illustrated diagrammatically in FIG. 7. Such discharge is made into the upper portion of a compartment which communicates at the lower end thereof with inlet receptacle 118, as best can be visualized from FIG. I. Said compartment has at least one vertical divider member 126 therein which results in the formation of two, adjacent discharge compartments 128 and 130, the latter being spaced transversely farther from the elevating apparatus 82 than the compartment 128.

From the foregoing, the preferred mode of operation of this mechanism is that the cleaned sand particles, being smaller than the pieces and particles of material comprising a limited number of sand grains still bonded by the bonding material, will be thrown by said aforementioned centrifugal force a greater distance from the elevating apparatus 82 than said larger pieces. An attempt has been made to illustrate this effect in FIG. 7, wherein it will be seen that the cleaned sand grains 132, due to their weight, the height of the upper edge of divider member 126, and the speed of the elevating means, have been projected into discharge compartment 130, while the heavier pieces which have not yet been thoroughly scoured or separated into individual clean grains of sand, do not travel laterally as far as the cleaned grains 132 and therefore are discharged into compartment 128 for return to scouring compartment 12 through the inlet opening 120.

The discharge compartment 130 also has a movable door or bottom member 134 which is mounted for movement between open and closed positions, the closed position being illustrated in FIG. 7, while the open position is illustrated in FIG. 8. Although the movable member 34 is illustrated as being hingedly connected to one wall of the compartment 90, said member could just as readily be of a transversely slidable nature supported in suitable horizontal guides, not shown. In the illustrtaed embodiment, however, it will be seen that the member 134 is provided with a positioning arm 136 extending therefrom, the outer end thereof being engageable by an adjustmentholding arm 138 which is provided with a plurality of notches 140 selectively engageable with the outer end of the arm 136 for securing the movable member 134 in either fully closed position, as shown in FIG. 7, or in a selected open position, as illustrated in exemplary manner in FIG. 8.

The movable member 134 is moved to open position especially during the initial cycle portion of treating a new batch of material, for example, under which circumstances, the material may be recycled as much as 40 or 50 times before it has been sufficiently treated to include an adequate percentage of cleaned sand grains to warrant commencement of removal thereof from the system. Hence, when the movable member 134 is in a selected open position, as shown by way of an exemplary illustration in FIG. 8, any material which might happen to be thrown into compartment 130 during the elevation and recycling of the material automatically will be returned to the scouring compartment 12 along with all of the material introduced into compartment 128. However, when, either from inspection of the material in the system, it is apparent that such initial processing has continued a desired extent, or by appropriate timing determined empirically from prior use that the initial processing is adequate, the member 134 is moved to the closed position illustrated in FIG. 7 and is held there by arrangement of the holding arm 138 against positioning arm 136. This will result in the discharge of finished, cleaned product sand grains by the apparatus now to be described.

As set forth hereinabove, the atmosphere in the upper portion of compartment 90 is continuously withdrawn, together with dust particles entrained therein, through the vacuum conduit 92 communicating with the upper portion thereof, as shown in FIGS. 1, 7 and 8. Said dust particles will comprise waste, powdered bonding material which has been abraded from the sand grains, as well as a limited amount of pulverized sand grains which, through the action of grinding wheel 5, or otherwise, have ben disintegrated to a smaller size than is useful. Such operation of the vacuum conduit 92 serves as the final means to remove any remaining dust particles of bonding material or otherwise from the cleaned sand product 132.

The transverse position of the movable member 134, as shown in FIG. 7, serves to effect an accumulation of cleaned sand grain product within compartment 130 upon said member 134. Formed in one wall of compartment 90 is a vertical discharge opening 142, shown in FIGS. 7 and 8, the area of said opening being controlled by a vertically adjustable door 144 movable in suitable guides 146 and held by friction or otherwise in any desired vertically adjusted position. When the accumlated material 132 has assumed a level above the opening 142, the cleaned product will fall by gravity into any appropriate discharge means such as chute 148 to direct the material into a clasifying means such as screen 150, primarily as a precaution to insure that any pieces or particles of bonded sand grains which require further processing and which accidentally may have been thrown into discharge compartment 130, are not contained in the bulk of cleaned sand grain products which, upon passing through the screen 150, are directed to storage or transportation means for eventual reuse in the formation of sand cores, mold forms, and the like, after suitable new bonding material has been added thereto.

For the foregoing it will be seen that a process and apparatus comprising certain embodiments of a complete machine or system for reconditioning bonded sand grains for reuse are provided, such machine and system, as well as the process performed thereby, requiring only economical use of power, mini-mum maintenance of the machine and system, and various adjustments of controls contained therein are adequate to permit the machine and system, and also the process to be employed in connection with used sand material bonded with a relatively wide range of different bonding compounds, certain of which require different cycling periods to which the present invention readily is adaptable by ready adjustment of the various control means referred to.

While the invention has been described and illustrated in its several preferred embodiments, it is to be understood that the invention is not to be limited to the precise details herein illustrated and described, since the same may be carried out in other ways falling within the scope of the invention as claimed.

I claim:

1. A machine to reclaim and clean bonded foundry sand comprising in combination, a scouring chamber having a bottom, means to feed to said chamber particles and pieces of used sand molds formed from bonded sand grains produced by shake-out operations, stationary members projecting radially into said chamber from the walls thereof at a level above the bottom of said chamber, and rotatable means engaging said material as accumulated in the bottom of said chamber and operable to fling the same upwardly against said radial stationary members to cause disintegration of the pieces and particles and also produce abrasion and friction within the material to scour the bonding material from the sand grains, and means to separate the removed bonding material from the cleaned sand grains.

2. The machine according to claim 1 in which said stationary members have yieldable surfaces engaged by the material being flung thereagainst, thereby to induce rebounding movement of said material and enhance the scouring thereof by interengagement between particles and grains of said material.

3. The machine according to claim 1 in which said rotatable means comprises a plurality of similar radially extending impeller members engageable with said 'material and shaped to deflect said material upwardly to impinge against said radial stationary members.

4. The machine according to claim 3 in which at least the lower portion of said scouring chamber is substantially cylindrical and the terminal ends of said impeller members are spaced a limited distance from the inner surface of said chamber and are substantially coextensive in a radial direction with but spaced below said stationary radial members which project inward from the inner surface of said scouring chamber.

5. The machine according to claim 1 further including suction means having an entrance for Waste bonding material separated from said particles located within the scouring zone of said chamber and operable to move such dust from said zone as it is formed, thereby to enhance the scouring action of the material still requiring scouring.

6. The machine according to claim 1 in which said stationary members are blade-like and are supported in substantially vertical position to provide means of substantial area against which material is impinged by impact by said rotatable flinging means.

7. A machine to reclaim and clean bonded foundry sand comprising in combination, reduction means to receive lumps, pieces and particles of used sand molds formed from bonded sand resulting from shake-out operations and operable to reduce the same to relatively small particle and grain sizes, a scouring chamber having a bottom below said reduction means, means to discharge reduced material from said reduction means by gravity into said scouring chamber, stationary members projecting radially into said chamber from the Walls thereof at a level above said bottom thereof, rotatable means engaging said material in the bottom of said chamber and operable to fling the same upwardly against said radial stationary members to cause disintegration of the pieces and particles and also produce abrasion and friction 7 within the material to cause scouring of the bonding material from the sand grains, and means to separate the removed bonding material from the cleaned sand grains.

8. The machine according to claim 7 in which said reduction means includes grinding mechanism to effect reduction of said lumps and pieces and also effects at least partial abrasion of the bonding material to enhance the removal thereof from the sand grains.

9. The machine according to claim 7 further including suction means having an inlet positioned between said reduction means and said rotatable means and operable to withdraw from said scouring chamber waste bonding material removed from said sand particles.

19. The machine according to claim 7 further including a shaft rotatable about a vertical axis within said machine and extending between said reduction means and said rotatable means, said reduction means including a grinding member fixed to said shaft and rotatable thereby commonly with said rotatable means in said scouring chamber.

11. The machine according to claim 7 further characterized by said rotatable means being disc-like and having a periphery substantially in vertical alignment with the inner ends of said stationary members, and said disc-like means having impellers circumferentially spaced around the periphery of said rotatable means and spaced below said stationary members, said impellers being shaped to engage said material in said scouring chamber and defiect it upwardly against said stationary members for impact therewith to cause abrasion of said bondingmaterial and disintegration of clusters of bonded grains of sand.

12. IA machine to reclaim and clean bonded foundry sand comprising in combination, reduction means including a substantially cylindrical stationary container to receive lumps, pieces and particles of used sand molds formed from bonded sand resulting from shake-out operations, a grinding wheel rotatable about a substantially vertical axis within said container and operable to reduce said material to relatively small particle and grain sizes, means to discharge the same from said reduction means substantially in a falling stream, a scouring chamber below said stationary container communicating therewith to receive the falling material, stationary members projecting radially into said chamber from the walls thereof at a level above the bottom of said chamber, rotatablemeans below said stationary members having a diameter similar to said grinding wheel, impeller members projecting radially from the periphery thereof to engage said material in said chamber and operable to fling the same upwardly against said radial stationary members to cause disintegration of the pieces and particles and also cause abrasion of the material to effect scouring of the bonding material from the sand grains, and means to separate the removed bonding material from the cleaned sand grains.

13. The machine according to claim 12 in which said stationary radial members have a yieldable rubber-like surface engaged by said material to induce rebounding of the material engaging the same and thereby enhance the scouring of said material.

14. A machine to reclaim and clean foundry sand comprising in combination, means to receive lumps, pieces and particles of used molding sand and operable to reduce the 1? at least to small pieces and grain size,

chamber means to receive said reduced pieces and grains, means within said chamber operable to scour said material to remove at least some of the bonding material from said pieces and grains, means to remove the partially scoured material from said chamber and recycle it to. the upper portion of said chamber, and additional scouring means in said chamber above said first-mentioned scouring means comprising members movable rapidly transversely to the path of the material reintroduced into the upper portion of said chamber to cause sharp impact with said material and thereby produce additional scouring of the material prior to the same being re-engaged by said first-mentioned scouring means.

15. The machine according to claim 14 in which said additional scouring means comprise radially extending members rotatable about a vertical axis, said material which is reintroduced for recycling being directed so as to by-pass said material reduction means.

16. The machine according to claim 15 in which said means to reduce said used molding sand pieces and particles comprises a rotatable grinding wheel and said radially extending additional scouring means are supported by and project outwardly from the periphery of said grinding wheel.

17. The machine according to claim 14 in which said additional scouring means have yieldable rubber-like surfaces engaging said material to induce rebounding of the material and thereby enhance the scouring of said material.

18. A process of reclaiming bonded foundry sand from lumps, pieces and particles thereof resulting from shakeout operations and comprising the steps of subjecting pieces and particles of bonded sand grains repeatedly to sharp impact made relative to a yieldable rubber-like surface to induce rebounding movement of the material and effect further impact and abrasion within the moving mass of material being subjected to said first-mentioned impact, thereby to separate the material into individual grains and simultaneously abrade the adhering bonding material therefrom, and separating the sand grains thus cleaned from the waste abraded bonding material.

19. The process according to claim 18 further characterized by the first-mentioned impact being produced by impinging the material against stationary means.

20. The process according to claim 18 further characterized by producing said first-mentioned impact by contacting a falling stream of said material with a rapidly moving means intersecting said stream substantially transversely to the direction of movement of said stream.

21. The process according to claim 20 additionally including the step of impinging the material against stationary means having a yieldable rubber-like surface.

22 A machine to reclaim and clean foundry sand comprising in combination, means to receive lumps, pieces and particles of used molding sand and operable to reduce the same at least to small pieces and grain size, chamber means to receive said reduced pieces and grains, means within said chamber operable to scour said material to remove at least some of the bonding material from said pieces and grains, means to discharge the partially scoured material from said chamber, a flexible conveyor positioned to receive said partially scoured material discharged from said chamber and including scoops movable over and around a transverse axis to dump said material from said scoops at a speed adequate to cause centrifugal force to distribute said material transversely at the upper end of the conveyor in a manner such that the lighter weight cleaned sand grains are dispersed farthest from the conveyor while the heavier pieces of material are closer to the conveyor, and compartment means into which said conveyor buckets discharge said material, said compartment means having a vertical divider therein to form two compartments, both compartments being arranged to discharge into said scouring chamber, one of said compart- 13 ments having another discharge exit arranged to discharge clean sand from said machine, said one compartment also having a closure member therein below said another discharge exit and movable between open and closed position with respect to passage of material through said compartment to said scouring chamber, whereby when said closure member is in open position material passes directly through said compartment to said scouring chamber for full recycling of all of said material as during initial scouring of a batch of material until scouring has progressed sufficiently that product discharge is desired, whereupon said closure member is closed to permit discharge of cleaned sand from said another discharge exit in said one compartment.

References Cited by the Examiner UNITED STATES PATENTS 2,468,321 4/1949 Bland 24124 2,707,314 5/1955 Horth 2289 2,821,375 1/1958 Andrews 22-89 10 WILLIAM W. DYER, 111., Primary Examiner.

G. A. DOST, 111., Examiner.