US2420392A - Foundry sand reclaiming system and method - Google Patents

Description

SEBTCU HOOm May 13, 1947.

A. c. cHRlsTENsl-:N Er AL 2,420,392

FOUNDRY SAND RECLAIMING SYSTEM AND METHOD Filed Dec. 2l, 1942 5 Sheets-Sheet l Search Room May 13, 1947- A. c. cHRlsTENsEN n Al. 2,420,392

FOUNDRY SAND RECLAIMING SYSTEM AND METHOD Filed Dec. 21, 1942 5 Sheets-Sheet 2 STD /75 -2 May 13, l947- A. c. cHRlsTENsEN Er AL 2,420,392

FOUNDRY SAND RECLAIMING SYSTEM AND METHOD Filed Dec. 21, 1942 5 Sheets-Sheet I5 D92 TCH KOOU! May 13,1947- A. c. cHRlsTENsEN Er Al. 2,420,392

FOUNDRY SAND RECLAIMING SYSTEM AND METHOD Filed Deo. 21, 1942 5 Sheets-Sheet 4 /ed Sie 71:5 e f? {Ja/mas Tjah/orafi.

Search Rom? May 13, 1947 A. c. cHRlsTENsEN Er AL 2,420,392

FOUNDRY SAND RECLAIMING SYSTEM AND METHOD Filed Dec. 2l, 1942 5 Sheets-Sheet 5 s 77 EME/1775755 Patented May 13, 1947 Search Room FOUNDRY SAND RECLAIMING SYSTEM AND METHOD Alfred C. Christensen and James J. Dvorak, Chicago, Ill., assignors to Herbert S. Simpson,

Evanston, Ill- Application December 21, 1942, Serial No. 469,662

(Cl. :Z2- 89) Claims.

This invention relates to a method of and apparatus for more efficiently reclaiming spentl and inert used materials by subjecting batches thereof to dry and Wet independently timed treatments during a course of travel through a continuously descending gravity feed line.

This invention is a continuation-in-part of our pending application for patent for a Foundry sand reclaiming system and method, led February 7, 1942, U. S. Serial No. 429,916.

The present invention, more specifically, relates to an improved and eflicient combination dry and wet reclamation system for used materials, such as spent foundry sand and the like, said system including independently timed treatments administeredin sequence to measured batches of the material as the batches are simultaneously advanced through a continuously descending gravity feed line, whereby the material not only has the foreign bond substances removed but also has a good percentage of the carbonaceous coating eliminated from the grains thereby producing a resultant reclaimed graded material of substantially its original color.

It is an object of this invention to provide an improved method of and apparatus for reclaiming spent or inert used materials by 4subjecting the materials to dry and wet treatments to produce a clean, graded and bleeched resultant material.

It is also an object of this invention to provide an improved method of and apparatus for reclaiming spent foundry sand and the like, which method is economical, clean and effective.

It is a further object of this invention to provide a gravity feed apparatus for reconditioning previously bonded used granular materials such as used for the making of foundry castings and the like, in order to remove scale, dust and other foreign matter to produce a resultant material which is dried, bleached and graded and is suitable for repeated use.

Another oLJect of this invention is the provision of an apparatus for cleaning and separating material particles of various sizes, which apparatus is arranged to effect a continuously descending gravity feed course and which apparatus is relatively compact and eiiicient as to floor space.

It is furthermore an object of this invention to provide a method of and an apparatus for cleaning and sorting granular materials to restore the materials for re-use by subjecting the materials to a dry cleaning treatment and subsequently converting the material into a pastelike substance and then, hydraulically treating the paste-like material and eventually drying the resultant graded material as it completes a cycle of treatment.

Another object of the invention is the provision of a continuous batch treating system for the reclaiming of foundry sand and the like, said system embodying combination dry and Wet treatment adapted to reclaim a high percentage of the sand at a cost materially less than the cost of providing new sand.

A further object of the invention is to provide an improved combination dry and wet treatments for the reclaiming of foundry sand and the like, by means of a gravity feed system for the continuous batch treatment of the sand in timed sequences including hydraulic steps arranged for re-using the water to effect a reduction in the cost of operations of the system.

It is an important object of this invention to provide an improved method of and apparatus for reconditioning spent or inert granular materials by compactly arranging different treatment units of the system to eiect a continuously descending gravity feed course for the material through the system by having the various treatment units arranged with independent timing controls connected in a timing system whereby the treated material is separated in batches, with said batches being conducted through continuous cycles in stepped sequences through the apparatus to effect a clean, bleached and graded restoration of the material for re-use.

Another important object of the invention is the provision of an improved and effective method of and apparatus for the reconditioning of spent granular material by a gravity feed of the material through a cycle of operations and treatments in which the material is advanced in predetermined quantities and subjected to a dry cleaning including the removal of fines therefrom after which the material is converted by means of moisture into a paste-like substance which is subsequently subject to desilting and elutriating steps to be wet cleaned and graded and then delivered to a centrifuging treatment to be dried to produce a reclaimed material which is not only cleaned and graded but which is substantially restored to its original color.

Other and further important objects of this invention will be apparent from the disclosures in the specification and the accompanying drawings.

In the drawings:

Figure 1 is a fragmentary front elevational view, in schematic form, of a foundry sand reclaiming system and a time control (embodying the principles of this invention) connected with various elements of the system for automatically timing the operation of the cycle of operations and the various steps thereof.

Figure 2 is a wiring diagram of the electrical control of the cycle of operations of the system and including parts of the various elements in the cycle which are governed by the timers.

Figure 3 is an enlarged sectional view of the upper third of the system including the first three steps of the cycle and the circuits therefor including the total cycle timer and the water control timer for the wet scrubber unit.

Figure 4 is an enlarged fragmentary sectional view of the intermediate portion of the apparatus including the wet scrubber and the desilting unit with their respective timers and the wiring connections.

Figure 5 is an enlarged fragmentary sectional view of the lower section of the apparatus including the elutriating and centrifuging units together with their respective timers and the wiring connections therefor.

As shown in the drawings:

It is believed that the novel method or process, of this invention, may be readily understood from the following description of a machine or apparatus for practicing the same.

The improved combined dry and wet method or process for the reclaiming of spent or inert granular materials such as foundry sand and the like, is adapted to be accomplished more specifically by means of a machine or apparatus to which the materials which have previously been crushed and demetalized are delivered. The inert material such as spent foundry sand, which is to be treated and reclaimed is delivered in measured batches to a series of consecutively arranged treating units in independently timed sequences through consecutively continuous cycles for subjecting the batches of sand, after being measured, to dry scrubbing and dust suctioning, semi-wet scrubbing and mulling, desilting, elutriating and finally to a centrifuging treatment to finally discharge a reclaimed, cleaned, bleached and graded sand ready for re-use.

The spent or inert material, such as used foundry sand, after being crushed and having the metal particles removed therefrom, is delivered into an elevated supply bin or hopper I which is supported on an upper level of a structural framework, which has been omitted in the drawings and which may be of any desired construction for supporting the various units comprising the machine or apparatus of this invention. The supporting framework is supported upon a oor or foundation 2 which may be constructed of concrete or other suitable material and in which a pit or chamber 3 is provided.

The supply bin or hopper I is the uppermost of a plurality of treating units, which are arranged in a continuously descending sequence to provide a continuous gravity feed line for the material through the succeeding cycles of operation through which the material in measured batches is conducted.

The supply bin or hopper I has the lower portion thereof tapered to provide a restricted mouth or outlet neck 4. The material, which is to be weighed out in predetermined quantities or in batches, is carried in the supply bin I and is prevented from dropping out of the discharge neck 4 by means of a pair of curved or arcuate doors 5. Each of the doors 5 is provided with end arms 6 which are pivotally supported on pins or stub shafts 1. Each of the door arms 6, beyond the pivot point thereof, is provided with an integral gear segment 8. The gear segments 8 of the bin doors 5 intermesh so that when one of the doors 5 is opened or closed the other door will be simultaneously operated.

One of the bin doors 5 is provided with an arm 9 (Figure 3) to which the lower end of a. piston rod or stem I0 is pivotally connected. The piston rod I0 forms part of an air control mechanism comprising an air cylinder II which is secured on the exterior of the storage bin I by suitable supporting means. Engaged on the inner end of the piston rod I0 and slidably disposed within the air cylinder II is a piston head which is adapted to be slidably moved within the air cylinder Il by means of air pressure adapted to be admitted into the air cylinder alternately below the piston head and above the same respectively by a lower air tube I2 and an upper air tube i3. The lower air tube I2 is connected to one arm of a three-way coupling I4. Connected to the middle arm of the three-way coupling I4 is one end of an air pipe or tube I5. The other end of the air tube I 5 is connected to a solenoid operated air valve unit I6. Also connected with the solenoid operated air valve unit I6 is a -second air pipe or tube I'I, which as shown in Figure 3 ls connected to the middle arm of a pipe coupling I8 to another arm of which the upper air tube I3 is connected. Connected to the solenoid operated air valve unit I6 is an air supply pipe or tube I9 which is connected with any suitable source of compressed air.

For the purpose of controlling the operation of the airvalve unit I6, said unit is connected by means of wires 20 and 2I to a selected standard type of time switch unit 22, the internal wiring mechanisms of which are illustrated in the wiring diagrams shown in Figuresv 2 and 3. The feed control time switch unit 22 is mounted in a control board or casing 23 mounted on the machine framework in any suitable or accessible position or at a remote station from which it is desired to control the operation of the machine. The feed control time switch unit 22 is provided with an outer minute time set dial 24 which is adapted to be set when a lock nut or knob 25 is released. The time switch unit 22 is also provided with an inner dial 26 which is divided into sixty subdivisions for second timing. Both the dials 24 and 26 are adapted to be set with respect to an index mark 21 positioned on the front face of the casing of the time switch unit 22 after the dials have been set the lock nut or knob 25 is tightened to insure operation of the time switch.

For the purpose of measuring predetermined quantities or batches of the material to be reconditioned a batch measuring unit is mounted on the machine framework directlyoelow the outlet neck 4 of the supply bin I to eceive material therefrom when the bin contol doors 5 are opened. The measuring unit comprises a material measuring hopper 28, the open top of which is'beneath the discharge neck 4 of the bin I. The measuring hopper 28 has a tapered body portion which terminates in a discharge neck 29 the outlet of which is controlled by a pair of doors 30 which are of curved or arcuate shape having supporting arms 3| integrally formed on the ends thereof. The door arms 3| are pivotally supported on supporting pins or stub shafts 32 carried on opposite walls of the hopper neck Search Room 29. Each of the door arms 3| has a gear segment 33 formed on the upper end thereof. The gear segments 33 of each pair of arms 3I mesh with one another, so that when one of the doors 30 is actuated the opposite door will be operated.

Secured on one of the hopper control doors 30 is a door operating arm 34 to the outer end of which the outer end of a piston rod or stem 35 is pivotally connected. The piston rod 35 forms a part of an air controlled mechanism comprising an air cylinder 36 which is secured on the exterior of the measuring hopper 28. Engaged on the inner end of the piston rod 35 within the air cylinder 36 is a piston head which is adapted to be slidably moved within the air cylinder 3B by means of air pressure admitted into the cylinder below the piston head through a lower air tube 31 and above the piston head by means of an upper air tube 38. The lower air tube 31 is connected to the third end of a T-coupling I6, while the upper air tube 38 is connected to the third end of the T-coupling I4.

The two air controlled door operating mechanisms for the bin doors 5 and the hopper doors 3U are thus both connected to the same solenoid operated air valve unit I6 and to the same feed control time switch unit 22 which is adapted to be set to cause automatic operation, at timed intervals, of the solenoid operated air valve unit I6 to cause opening of the material discharge bin doors 5 and simultaneous closing of the hopper doors 3D when a charge of material to be delivered into the hopper 28, or closing of the doors 5 when the doors 30 are timed to be opened to discharge a measured charge of material from the hopper 28 into a material dry scrubbing and dust removing unit which performs the third step in the sequence of operations undergone by the material as it is advanced through a cycle of treatments to become reconditioned for re-use.

The dry scrubbing unit is supported on the machine framework at a level lower than that of the batch measuring unit to form an arrangement for continuing the gravity feed from the bin I, then to the hopper 28, and next to the dry scrubbing unit.

As clearly shown in Figures l and 3 the dry scrubbing unit comprises an upper scrubber casing section 39 having a material receiving mouth 4U. The dry scrubber top section 39 is secured on the upper end of a main dry scrubber casing 4I and has connected to one side thereof one end of a nes and dust discharge pipe 42. The lower end of the dust discharge pipe 42 is connected to a suction or exhaust ian housing 43 which is supported on a dust collector 44 mounted on the machine framework. A suction or exhaust fan within the housing 43 is connected to be operated by a driving motor 45. Attached to the upper end of the exhaust fan housing 43 is the lower end of an air outlet ue or pipe 46 through which air is permitted to escape to the atmosphere as fines and dust are delivered into the collector 44.

The dry scrubber casing 4I contains a motor driven rotor 41 formed with mixing paddles and Scrapers 48 for imparting a violent mixing and paddling .action to the material delivered by gravity into the dry scrubber casing 4I when the hopper doors 30 are opened and a pair of pivotally mounted dry scrubber casing discharge doors 49 are closed.

The closure doors 49 of the dry scrubber casing 4I have door operating arms 50 connected thereto. The outer ends of the arms 50 are pivotally connected to the outer end of a pair of piston rods or stems 5I which project from a pair of air cylinders 52 which are supported adjacent the opposite sides of the dry scrubber casing 4I. Each of the air cylinders 52 has a piston head therein engaged on the inner end of the piston rods 5I. The two cylinders 52 have their lower ends connected by a lower connecting air tube 53, while the upper ends of the cylinders 52 are connected by an upper air tube 54. The two piston mechanisms of the air cylinders 52 operate simultaneously to cause either simultaneous opening or closing of the dry scrubber doors 49.

Connected to the lower end of one of the dry scrubber cylinders 52 is one end of an air pressure pipe or tube 55 while one end of a second air pressure pipe or tube 56 is connected to the upper end of the same cylinder 52. The two air control tubes 55 and 56 are connected to a dry scrubber solenoid operated air valve unit 51 having an air pressure supply pipe or tube 58 connected thereto.

The air pressure supply to the air valve unit 51 is controlled by a solenoid within the unit 51 by means of two circuit wires 59 and 60 which are connected to the solenoid terminals to connect the control solenoid with a dry scrubber electric time switch unit 6I which is mounted on the control board 23 and is identical to the time switch unit The fourth step in the cycle of treatments of a batch of the material to be reconditioned, is performed by means of a combination dry and wet mixing, scouring and mulling unit which may be termed the wet scrubber unit. It is mounted upon the machine framework, directly beneath the discharge doors 49 of the dry scrubber unit to form another step in the gravity feed line course for the travel of the material through the machine. The wet scrubber unit comprises a materia] receiving hopper or chute 62, the lower discharge end of which projects into an upper casing section 63 which is mounted on the upper end of a mixing and mulling pan or casing 64 having a material discharge opening in the bottom of one side thereof adapted to be closed by means of a door 65. Axially disposed within the pan or casing 64 is a driving shaft set to be rotated by means of a motor 65. The driving shaft has secured on the upper end thereof, within the casing 64, a head 61 on which mixing and mulling wheels or mullers 68 are rotatably supported. Also carried by the rotatable head 61 are plows or scrapers 69 which are positioned to scrape the bottom and walls of the casing 64 and plow and deliver the material being treated into the path of travel of the rotating wheels or mullers 68,

In order to further dry clean the material in the casing 64 and convert the dry cleaning treatment into a semi-wet treatment to form a resultant paste of the treated material, the wet scr"'bber unit is provided with a water receiving funnel 10 having one or more water distributing pipes 1| projecting downwardly from the bottom or lower portion thereof for distributing the required amount of water or other liquid into the mixture contained within the casing 64. Projecting into the water receiving funnel 10 is the discharge end of a water feed pipe 12 which connects up with a water control solenoid operated water valve unit 13. Also connected to the water valve unit 13 is a water pipe 14 having a shut-off valve 15 connected therein. Shunted around the shutoff valve 15 is a by-pass pipe 16 (Figure l) in which a water pressure regulating valve unit 11 is connected; to assure a constant water pressure in the water supply line leading to the solenoid valve unit 13.

For the purpose of controlling the timing operation of the water valve unit 13 the solenoid thereof has connected to the terminal thereof two circuit wires 18 and 19 which lead to a water controlled electric time switch unit 80 which is mounted on the control board 3 and is identical to the time switch unit 22.

As illustrated, in Figure l, the water pipe 14 is also connected to a desilter water supply pipe 8| which, in turn, connects up with a main water supply pipe 82 having a control or shut-off valve 83 connected therein.

A batch of material which has just been dry scrubbed and from which the nes or dust has been removed is dropped into the receiving hopper or chute 62 of the wet scrubber and is delivered into the casing 64, when the muller casing discharge door 65 is closed and when the dry scrubber discharge doors 49 are opened. The advanced batch of material delivered through the gravity feed line to the mulling casing 64 is first further dry cleaned and then has a predetermined quantity of water discharged thereon, to be mixed therewith, to produce a paste-like substance which is subjected to a thorough mixing and mulling actions for a predetermined length of time determined by the opening of the muller casing discharge door 65.

For the purpose of controlling the operation of the door 65 at timed intervals, the door is provided with an operating or actuatingarm 84 to which the outer end of a piston rod or stem 85 is pivotally connected. The piston rod 85 projects into an air cylinder 96 and has a. piston head secured on the inner end of the rod 85 to be reciprocated by air pressure. Connected to the lower end of thev air cylinder 86 is one end of an air pipe 81. Also connected to the air cylinder 86. at the upper end thereof, is another air pipe 88. Both the air pipes 81 and 88 are connected to a wet scrubber solenoid operated air valve unit 89 having an air supply pipe 90 connected to the air valve within the valve unit. Connected to two terminals of the solenoid within the wet scrubber valve unit are two circuit Wires 9| and 92 which are also connected to two terminals of a wet scrubber control electric time switch unit 93 which is mounted on the control board 23 and is identical to the time switch unit 22.

After the wet paste-like material has been treated to wet scrub the particles thereof within the wet scrubber casing 64, the casing door 65 is A automatically opened and the paste-like contents is discharged through a chute 94 into a desilting unit which is mounted on the machine framework at a level below the level of the wet scrubber unit so that the feed of material from the wet scrubber unit to the desilting unit may be accomplished by the action of gravity to complete another step in the gravity feed line course of the material through the machine. The desilter unit comprises a conical container or tank 95 into which the lower discharge end of the feed chute 94 projects. The upper end of the desilter tank 95 is open and projects part way into a circular or circumferential launder 96 which is provided for the purpose of receiving and discharging the resultant organic matter and silt which is separated from the bath being treated by the desilting operations. Leading downwardly from the desilter launder 96 is a discharge pipe 91 which projects downwardly through the floor 2 and the pit 3 and connects up with a sewer unit 98. 'I'he lower tapered end of the desilter casing or tank terminates in a discharge valve casing 99 having a valve seat |00 formed therein with which a discharge control valve |0| co-acts. The discharge control valve IDI is connected to the lower end of a valve stem |02 which projects upwardly through a rotatable hollow shaft |03 and upwardly out of the desilter casing or tank 95 with the upper end of the valve stem or piston rod |02 projecting into an air cylinder |04 to be operated by a piston head within said cylinder when the same is operated by air pressure to control opening and closing of the desilter discharge valve |0I.

Connected to the lower end of the air controlled cylinder |04 is an air pipe |05. A second air pipe |06 is connected to the upper end of the cylinder |04. Both the air cylinder pipes |05 and I 06 are connected with a desilter solenoid operated air valve unit |01 to which an air pressure supply pipe |08 is also connected to supply air pressure to the pipes |05 and |06 through a valve within the 'unit |01. The control valve within the unit |01 is adapted to be operated by means of an electric solenoid to the terminals of which two circuit wires |09 and III) are connected. The two circuit wires |09 and |I0 are connected with a desilter control electric time switch unit |II which is mounted on the control board 23 and is identical to the time switch 22.

For the purpose of accomplishing a desilting treatment of the paste-like material, which is discharged from the wet scrubber into the desilter, a water agitating and circulating turbine type wheel II2 is horizontally positioned within the desilter casing 95 and is secured to the lower end of the hollow rotatable shaft |03 to be rotated thereby. The desilter unit is provided with an operating motor H3 for causing rotation of the shaft |03 and the water agitating wheel II2. The motor ||3 is provided with circuit wires I|4 and II5 which connect up to a source of electrical energy. A control switch I I6 is connected in the circuit wire I I4 for the purpose of controlling the operation of the motor I3.

For the purpose of admitting water into the desilter casing or tank 95 the desilter is provided with a circular water pipe I I1 to which the Water supply pipe 8| is connected. Branching from the circular water pipe I|1 are a plurality of auxiliary feed pipes I I8 which project into the lower end of thev desilter casing or tank 95 to project water under pressure into the tank. Water admitted into the desilter tank 95 through the auxiliary pipes ||8 is brought into contact with the motor driven turbine type wheel I|2 to cause the water to be thoroughly agitated and circulated in the lower portion of the desilter casing so that the paste-like material which has been deposited into the casing 95 is thoroughly broken up by the action of the water permitting the scrubbed and washed sand grains or granular particles to settle in the bottom of the casing and in the valve casing 99, while the silt and organic matter is carried upwardly by the water in the desilter casing or tank 95 and overflows into the launder 96 from which it is discharged through the discharge pipe 91 into the sewer 98. Connected to the lower end of the valve casing 99 and below the control valve |0I of the desilter, is a conical shaped discharge funnel or cup II9 having the upper end of a discharge pipe |20 connected thereto.

After the desilting treatment of the paste-like De?) TCH HUGH material the cleaned batch of material is now ready to be advanced another step in the cycle of operations into an elutriating unit for further washing and grading the material. At the end of a desilting treatment the time switch unit I I I operates to cause opening of the desilter valve |I thereby permitting the scoured and cleaned material from the desilter to be discharged into the funnel ||9 and through the discharge pipe |20 into an elutriating unit for further treatment.

The elutriating unit is mounted on the machine framework at a level below the level of the desilting unit to form an arrangement whereby the material is continued to be fed downwardly by gravity. The elutriating unit comprises a tapered or conical shaped casing or tank |2| the upper end of which is open and into which the discharge end of the material feed pipe |20 projects in order to discharge a measured batch or quantity of the material being treated into the elutriating grading casing |2|. The upper open end of the elutriating casing |2| projects part way into a circumferential or circular launder |22. Connected to the launder |22 is the upper end of a water discharge pipe |23 which projects downwardly and enters into the upper portion of a water collecting reservoir |24 which is mounted in the pit 3. The water reservoir |24 is connected to the sewer 9B by means of a discharge pipe |25 having a shut-01T or control valve |26 connected therein to permit draining of the tank |24 when necessary to permit removal of any sediment or the like which might accumulate in the reservoir |24. Also connected to the reservoir or tank |24 is an overow pipe |21 which is connected with the discharge pipe 91 leading into the sewer 98.

The lower end of the elutriating casing or tank |2| is provided with a valve seat at |28 surrounding a valve opening which is adapted to be closed by an elutriator control valve |29 for controlling the diszharge of cleaned graded material from the elutriator.

Surrounding the discharge mouth or valve end of the elutriator casing |2| is a circular or ring shaped water supply pipe |30 having a plurality of auxiliary water supply pipes |3| connected thereto and projecting into the elutriator casing |2|. Connected to the ring shaped water supply pipe |30 is the upper end of a water fiow gauge |32 for gauging or regulating the pressure of the flow of water to the elutriator. Connected to the lower end of the ow gauge |32 is a water supply pipe |33 which connects up with the main water supply pipe 82 and has a shut-off or control valve |34 connected therein.

Mounted on the floor 2 above the pit 3 is a water pump |35, having connected thereto one end of a water pipe |36 having the intake end thereof projecting downwardly into the water reservoir |24 so that used water from the launder |22 owing downwardly through the discharge pipe |23 and used water from a centrifuging unit. hereinafter described. is returned into the reservoir |24. 'Ihe supply of fresh water from the main supply pipe 02 may be shut off by means of the control valve 83 (Figure l) so that the previously used water stored in the reservoir |24 may be re-used by operation of the pump |35 which pumps the water from the reservoir up through a pipe |36 which connects the pump |35 with the pipe |33 so that the previously used water may be re-used in the desilter and in the elutriator thereby providing an arrangement for reducing the water consumption and the cost of operation of the entire system.

The water under pressure entering the elutriator casing or tank |2| through the auxiliary pipes |3| is directed upwardly and is adapted to be thoroughly agitated by means of a turbine type of water wheel |31 which is horizontally disposed in the elutriator casing |2|. The Wheel |31 is supported on a rotatable hollow shaft |38 which extends upwardly out of the casing |2| and is connected to be operated by means of an elutriator operating motor |39 having circuit wires |40 and |4| connected thereto and to a suitable source of electrical energy. Mounted in the circuit wire |4| is a motor control switch |42 f Figure 5) to provide an arrangement whereby the elutriator motor may have a private control circuit. or the circuit wires for the motor may be connected with the main power line of the system, as preferred. When the control switch |42 of the motor |30 is closed the elutriator agitating wheel |31 is rotated so that the water within the casing |2| is thoroughly agitated as is also the material discharged into the elutriator from the desilter discharge pipe |20. The elutriator acts as a means for agitating the substantially cleaned sand grains or material particles so that the lighter particles are carried upwardly by the water stream while the heavier grains are permitted to settle toward the bottom of the elutriator casing 2| As the lighter grains and any remaining particles of the material are conveyed upwardly they flow over the top edge of the elutriator casing |2| into the launder |22 and then downwardly through the discharge pipe |23 into the reservoir |24 so that only material cleaned grains of a graded size remain in the elutriator. The grading of the cleaned material in the elutriator casing |2| may be regulated by the water gauge |32 to determine the pressure of the water entering the elutriator casing through the pipes |30 and |3|. By the time the material being treated has completed the elutriating treatment, it is thoroughly scrubbed and washed and graded.

The various treatments accorded the material passing through the cycle of operations act to remove not only the foreign bond materials from the material grains but also acts to remove a large percentage of any of the carbonaceous coating from the grains, which is a highly desirable factor in the reclaiming of spent foundry sand on which an oil bond has been used.

For the purpose of controlling the discharge of the cleaned and graded material from the elutriator casing |2| the elutriator control valve |29 is adapted to be operated by a piston rod or valve stem |43 which projects upwardly through the hollow shaft 38 and extends into an air cylinder |44 which contains a piston head secured on the upper end of the piston rod |43.

Connected to the lower end of the air cylinder |44 is one end of an air pressure pipe or tube |45. A second air pressure pipe or tube |46 is connected to the upper portion of the cylinder |44. The two air control pipes or tubes |45 and |46 are connected to an elutriator solenoid operated air valve unit |41 having an air pressure supply pipe or tube |48 connected thereto. The air pressure control valve in the unit |41 is controlled by a solenoid within said unit. Connected to the terminals of the solenoid are two circuit wires |419 and |50 which are connected with an elutriator electric time switch unit |5| which is mounted on the control board 23 and is identical to the time switch unit 22. The elutriator casing |2 has the valve |29 thereof controlled by the timer switch and said valve |29 is not opened to permit discharge of the material therefrom into a centrifuging unit until said centrifuging unit has first been emptied. Connected to the lower discharge end of the elutriator casing |2| is a cone shaped discharge funnel |52 having a discharge pipe |53 connected to the lower end thereof and arranged with the discharge end thereof positioned to discharge a measured cleaned and graded batch of reclaimed material into a centrifuging unit which is adapted to perform the last step in the cycle of treatments to which the batches of material are subjected in their gravitational descent through the machine,

The centrifuging unit is provided to receive the graded, washed and scoured material and to subject the same to a dehydrating treatment to extract the water therefrom to render the cleaned reclaimed material substantially dry and restored to its normal color ready to be discharged for re-use.

The centrifuging unit comprises a casing or tank |54 which is supported on the iioor 2 and has an opening |55 in the bottom thereof surrounded by an upwardly projecting flange |56 which forms an annular water-collecting trough in the bottom of the centrifuging tank |54, from which the water is adapted to be drained through a pipe |51. The discharge end of the pipe |51 projects downwardly into the water collecting reservoir |24 to permit the water from the centrifuge to be re-used in the system. As clearly illustrated in Figure 5, the centrifuging tank |54 is positioned so that the opening |55 thereof registers with an opening formed by a collar or ring |58 in the oor 2 above the pit 3. Attached to the bottom of the collar |58 is a material discharge funnel or chute |59 the lower end or discharge mouth of which is positioned above an endless conveyor |60 which is positioned in the pit 3 and which leads outwardly therefrom to deliver the reclaimed or reconditioned material for re-use.

A centrifuge framework |6| is supported on the floor 2 and extends above the tank |54 and has supported on the upper end thereof a downwardly projecting shaft |62. The lower end of the centrifuge shaft |62 is suspended in the tank |54 and has secured on the lower end thereof a conical shaped discharge mouth or funnel |63 which projects through the opening in the bottom of the tank |54 and into the collar |58 for delivery of material to the discharge chute |59. The discharge mouth |63 is supported on the shaft |62 by a plurality of radially directed fins or blades connected to a collar secured on the lower end of the shaft. Secured on the shaft 62 above the discharge mouth |63 is a material receiving disk |64 upon which material from the elutriator is discharged from the pipe |53, so that the cleaned graded material striking the disk |64, while the same is being rotated, rebounds and is discharged centrifugally outwardly into a mesh basket |65 which is secured on the upper flanged end of the mouth |63 and is provided with a top |66 having a central opening through which the shaft |62 and the discharge end of the pipe |53 projects. The material discharged by centrifugal force from the baffle disk |64 when the same is rotated, is discharged outwardly against the walls of the mesh basket |65 thereby permitting the material to be dehydrated allowing the discharged water to pass outwardly through the mesh openings in the mesh basket 65 and drop into the 12 discharge trough in the bottom of the tank |54. The material which undergoes the centrifuging action is thus dried and is discharged through the discharge mouth |63 of the basket |65 and through the funnel or chute |59 onto the conveyor |60.

The upper end of the centrifuging shaft |62 is adapted to be driven by a motor |61 supported on the framework |6|. The motor |61 is connected by means of wires |68 and 69 with a suitable source of electrical energy or to the main power line of the system. Connected in the wire |69 is a motor control switch |10. For the purpose of slowing down or braking the operation of the centrifuge motor |61 a solenoid operated brake unit |1| is secured to one side of the motor casing. Connected to the terminals of the solenoid of the brake unit 1| is a circuit'wire |12 and a circuit wire |13. The solenoid circuit wire |12 is connected to a terminal 2 of a centrifuge control electric time switch unit |14 which is mounted on the control board 23 and is identical to the time switch unit 22.

Referring now to the timed automatic control of the consecutive cycles of operation and treatment of material batches which are gravity fed through the machine to be reclaimed and reconditioned, the control circuit comprises main power lines |15 and |16 for the supply of alternating current. Connected in the main power line is a main double throw starting switch |11 for controlling the starting and stopping of the control circuit.

Included in the complete electric circuit for the system are nine standard types of time switches namely, a total cycle time switch |18, the feed control time switch 22 for controlling the feeding of material from the supply and measuring the material in batches, the water control time switch for governing the time and amount of water to be admitted into the wet scrubber unit, the dry scrubber discharge door control time switch 6|, the wet scrubber control time switch 93, the desilter control time switch the elutriator control time switch |5|, the centrifuge control time switch |14 and a cycle reset time switch |19.

All of the nine time switches are of the same standard type and each is provided with a dial lock nut or knob 25 which is adapted to be loosened for setting the dials. Each time switch includes an outer minute time set dial 24 and an inner second time switch dial 26. With the lock knob loosened the minute dial 24 is set for the required time setting in minutes, after which the second dial is set for the required time setting in seconds. The outer dial 24 moves one division for each revolution of the inner dial 26. The time setting is the sum of the readings of the outer and inner dials. After setting the dials, the lock knob 25 is tightened to insure operation of the timer.

Each of the nine time switches is provided with seven terminals, designated L1, AL, I, 2, B and M. In each time switch the terminals L1 and A are connected by a clutch coil C, and the terminals L1 and B are connected by a synchronous motor S. The terminals B and M of each time switch are connected by a connector bar or wire to connect two switch arms D and E. Connected to each terminal L2 is a contact finger 'I' with which switch arm D is positioned to coact. Connected to the terminal is a contact finger and a Contact nger 2 is connected to the terminal 2. The two switch contact fingers and 2 are posi- E-BTCH KOOm tioned on opposite sides of a switch arm E to be contacted thereby at timed intervals depending upon the setting of the time switch. In the total cycle time switch |18 and in the reset time switch |19 the terminal 2 and the contact finger 2 are not used.

In the complete circuit arrangement illustrated in Figure 2, the terminal |80 of the main control switch |11 has a circuit wire |8| connected thereto and said wire is connected at its other end to the Contact L1 of the total cycle time switch |18. The terminal L1 of the reset time switch |19 is connected by means of a circuit wire |82 through the line wire |8|. The terminal A of the reset time switch |19 is connected by means of a circuit wire |83 to the terminal l of the total cycle time switch. The terminal L2 of the reset time switch is connected by a circuit wire |84 to a line wire |85 one end of which is connected to the terminal |86 of the main switch |11. The other end of the line wire |85 is connected to the terminal L2 of the total cycle time switch |18. rPhe terminal of the reset time switch |19 has connected thereto one end of a circuit wire |81 the other end of which is connected to the terminal A of the total cycle time switch |18. The terminal 2 of the reset time switch |19 remains dead.

In all the time switches. except the reset time switch |19, the switch contacts T, and 2 are normally open. The reset time switch |19 normally has the switch contacts T and 2 open, while the switch contact is normally closed.

The circuit wire |12 from the centrifuge brake unit |1| is connected to the terminal 2 of the centrifuge time switch unit |14. The circuit wire |13 from the centrifuge brake unit |1| is connected to the centrifuge time switch terminal L1 and also to the line wire |8|` The terminal A of the centrifuge time switch |14 is connected by means of a wire |88 to the circuit wire |81 and the terminal L2 of the time switch |14 is connected by a wire |89 to the line wire |85. Connected to the terminal of the time switch |14 is a circuit wire |90 which leads to terminal A of time switch |5|.

rIhe elutriator wire |50 leading from the valve unit |41 is connected to the terminal 2 of the elutriator time switch |5| while the line wire |49 from the valve unit |41 connects to the terminal L1 of the time switch |5| and also to the line wire |8|. The terminal L2 of the time switch |5| is connected by means of a wire |9| to the line wire |85. Connected to the terminal of the time switch |5| is a wire |92 which is connecte-d to the terminal A of the time switch The wire |09 from the desilter valve unit 01 connects up to the terminal 2 of the time switch while the wire ||0 from the desilter valve unit |01 connects up to the terminal L1 of the desilter time switch and to the line wire |8|. A wire |93 connects the terminal L2 of the desilter time switch with the line wire |85. A wire |94 connects the terminal of the desilter time switch to the terminal A of the wet scrubber time switch 93.

The wire 9| leading from the wet scrubber valve unit 89 is connected to the terminal 2 of the time switch 93 while the wire 92 from the valve unit 89 is connected to the terminal L1 of the time switch 93 and also to the line Wire |8I. A wire |95 is connected to the terminal L2 of the time switch 93 and to the line wire |85. A wire |96 connects the terminal of the line 14 switch 93 with the terminal A of the dry scrubber time switch 6|.

The wire 59 from the dry scrubber valve unit 51 connects to the terminal 2 of the time switch 6| while the wire 60 from the valve unit 10 connects to the terminal L1 of the time switch 6| and also to the line wire |8|. A wire |91 connects the terminal L2 of the time switch 6| to the line wire |85. A wire |98 connects the terminal I of the time switch 6| to the terminal A of the water control time switch and also to the terminal A of the feeder batch control time switch 22.

The wire 18 from the water control valve unit 13 connects to the terminal 2 of the time switch 80 while the wire 19 from the valve unit 13 connects to the terminal L1 of the time switch 8i) and also to the line wire |8|. A wire |99 connects the terminal L2 of the time switch 80 to the line wire |85. The terminal of the time switch 80 remains dead.

The wire 20 from the batch control valve unit I6 connects to the terminal 2 of the time switch 22 while the wire 2| from the valve unit I6 connects to the terminal L1 of the time switch 22 and also to the line wire |8|. A wire 200 from the terminal L2 of the time switch 22 is connected to the line wire |85. The terminal of the time switch 22 remains dead.

By means of the control board 23 and the crono of nine time switches mounted thereon and connected with the various material treating mechanisms forming part of the sand reconditioning system, a selective timing arrangement is provided whereby the machine may be operated automatically for production control in the reclaiming or reconditioning of foundry sand and other similar materials.

The circuit arrangement is such that when the centrifuge unit completes the drying of a cleaned batch of material and the elutriator valve |29 is closed the centrifuge time switch |14 having been set for a predetermined time period of operation acts to brake the operation of the centrifuging mechanism to slow the same down thereby nermitting discharge and emptying of the centrifuge unit. When the brake is applied the motor control switch |10 is opened to prevent overloading of the motor. After the centrifuge unit is emptied the elutriator time switch |5| opens tle control or discharge valve |29 permitting a batch of treated material from the elutriator to be discharged into the centrifuge unit while the desilting unit by the action of its time switch remains closed until the centrifuge unit has been emptied and is ready to receive the next charge. In a similar manner the desilter unit is next o-pened to discharge its contents while the wet scrubber unit remains closed until the desilter is empty and ready to receive a charge. The wet scrubber unit after discharging its contents is closed and the dry scrubber unit is then opened to deposit a measured charge into the wet scrubber unit. in which the delivered charge is rst dry treated and then has water mixed therewith. When the dry scrubber unit is emptied and closed by its time control switch the batch mechanisms will deliver a measured charge or `batch of material when the doors of the measuring hopper 28 are opened and the doors of the supply hopper are closed. The time switch for the measuring hopper and the supply bin is such that when one opens the other closes.

'Ihe time switch circuit arrangement is such that the sequence of operations electrically is upwardly from the last or centrifuging treatment, so that a batch of material which has been treated is always discharged from a unit before a new batch of material is admitted. The me` chanical sequence of operations of course starts from the uppermost unit, where the material to be reconditioned is delivered and batch measured and is then fed downwardly by gravity in timed controlled steps from one treating unit into another until the cycle is completed. The cycle is controlled by the total time switch H8 which is set to cover a total period which may be greater or equal to the sum of the timing operations of the seven step treatment time switches, so that when a cycle of operations has been completed the reset time switch V19 will act to automatically cause resetting of the total time switch and the various other time switches so that the next cycle of operations may take place.

It will be noted that in this improved reconditioning system the machine is adapted to treat a plurality of batches in continuously repeated sequences, so that there is a batch of reconditioned material discharged from the machine onto the receiving conveyor |60 at the end of every period for which the various treatment time switches have been set. The treatment time switches are all set for the same length of time, so that there is an inter-related timed opening and closing for the adjacently positioned units without any danger of the intermixing of batches during the reconditioning cycle.

During the operation of the machine the water from the main supply pipe 82 is used to deliver water in the wet scrubber and to supply water under pressure to the desilting and the elutriating units. The water which has been used in the elutriating unit and in the centrifuging unit is comparatively clean and is discharged back into the reservoir |24. When the reservoir is filled suiiiciently, the main water supply may be shut oi or cut down so that the water from the reservoir may be reused by pumping the same into the water pipes-supplying the various units of the system.

The improved reclaiming system has the various treatment element steps arranged at different elevations to provide an arrangement whereby the material may be delivered and batch measured and then fed through a continuous downwardly directed course by the action of gravity thereby eliminating the need of providing pumps, conveyors and the like between the different units of the system. The substantially vertical arrangement of the various units has the further advantage of materially saving door space thereby reducing cost. By providing for the reuse of water in the system, a further reduction in operating cost is accomplished.

The automatic timing arrangement for the system is such that the various units may be properly timed to assure proper opening and closing of the same in relating to the adjacent units so that there will absolutely be no doubling up of the batches as the plurality of successive batches are advanced continuously through the cycles of operation.

It will, of course, be understood that various details of construction and steps in the method may be varied Without departing from the principles of this invention, and it is, therefore, not the purpose to limit the patent granted hereon otherwise than necessitated by the scope of the appended claims.

We claim as our invention:

1. The method or process of reclaiming foundry sand and the like for re-use, said method including subjecting a series of batches of material in continuous sequences, each batch to a different treatment as the series of batches are advanced downwardly through a gravity line as each batch of material is consecutively batch measured and intermittently advanced at predetermined intervals of time, subjecting an advanced measured batch of material to dry scrubbing and removing the nes by air suction, partially wetting the dry cleaned batch and subjecting the same to a scouring and mulling treatment to form a paste, treating the paste to a desilting operation and hydraulically removing organic and foreign matter from the resultant batch, subjecting the remainder of the batch to an elutriating action to grade the material and to wet scrub the same and hydraulically remove nes therefrom, and finally subjecting the resultant clean graded batch of material to a centrifugal dehydrating treatment to throw ofi the water and dry the reclaimed clean batch of material for re-use.

2. The combination dry and wet method of reclaiming used inert foundry sand or the like for re-use comprising advancing the material through a continuously descending line of travel by the action of gravity through a continuous sequence of timed operations comprising batch measuring the material and intermittently advancing the measured batch, subjecting the batch to dry scrubbing and suctioning nes therefrom, then wet scouring and mulling the batch leaving a paste-like batch, subjecting the paste-like batch to a desilting treatment and removing organic and foreign matter therefrom, then subjecting the resultant batch to elutriating actions to wet scrub and grade the material and further separating any remaining fines therefrom leaving a clean graded material, and finally centrifuging the resulting clean graded material to dehydrate and dry the material and then discharge the Same.

3. A foundry sand reclamation method consisting of simultaneously advancing batches of material in timed sequences through a continuously descending gravity feed line, each sequence of operations including batch measuring the material and subjecting the batch to dry scrubbing and suctioning to remove nes therefrom, sub-` jecting the batch to wet scouring and mulling treatments to produce a paste-like batch, applying desilting actions to the paste-like batch to remove organic and foreign matter therefrom, then subjecting the resultant batch to elutriating treatments to separate ne graded particles from heavier graded particles and then centrifuging the heavier graded particles to dehydrate and dry the same to produce thoroughly cleaned and substantially dry reclaimed graded sand ready for re-use.

4. The method of reclaiming foundry sand from used inert foundry shakeout material, said method including advancing the material through a continuously descending gravity feed line through a series o1' independently and collectively timed treatments consisting of dry cleaning and simultaneously removing nes from the mtaerial, subjecting said resultant material to wet scouring and mulling treatments to produce a paste-like substance, then desilting the paste-like substance to remove organic and foreign matter leaving a cleaned mixture of different sized sand grains, elutriating the mixture to carry off the ne sand grains and leaving the 17 heavier graded sand grains, and finally dehydrating the heavier graded sand grains by a centrifuglng treatment to dry the reclaimed graded sand for re-use.

5. The method of reclaiming foundry sand from used inert foundry shakeout material, said method including feeding the material intermittently through a continuously descending gravity feed line through a series of automatically timed operating and rest steps consisting of measuring and dry cleaning the material and suctioning off the resultant nes, wetting the material and simultaneously scouring and mulling the same to form a paste-like substance, grading the pastelike substance by subjecting the same consecutively to desilting and elutriating actions, and finally subjecting the cleaned graded material to a centrifuging treatment to dry the same ready for re-use.

6. The method of reclaiming inert granular materials for re-use consisting of gravity feeding the material in separated measured batches through consecutive sequences of independently timed steps each having timed operating and rest intervals for controlling the advance of the batches independently through separately consummated dry cleaning treatments involving air removal of resultant fines, and separately consummated wet cleaning treatments for scouring, scrubbing and then grading theclean sand, and finally dehydrating the resultant graded sand to dry the same ready for re-use.

7. The continuous batch processing of previously used material to reclaim graded cleaned quantities thereof by independently conducting measured batches of the material through a continuously descending gravity feed line through inter-timed separately consummated steps each including timed operating and rest intervals, said steps consisting of dry cleaning and scrubbing the material and suctioning nes therefrom, then wet treating and cleaning the material and hydraulically grading out the re-usable cleaned quantities of the material, and finally subjecting the cleaned graded material to dehydrating treatments to dry the same ready for re-use.

8. A foundry sand reclaiming system comprising in combination a supply hopper for carrying crushed demetalized inert foundry sand for reclamation, means therebelow for measuring the sand into batches, means for independently dry scrubbing and air suctioning the batches, means for wetting, scouring and mulling the sand batches to form a sand paste of each batch, means for receiving the paste including means for desilting the paste by removing organic and foreign matter therefrom leaving cleaned sand, means for elutriating the cleaned said to grade the same, means for centrifugally drying the graded sand for re-use, all of said means being connected one below the other in the order mentioned in a continuously descending series to 18 form a continuous gravity feed line for the system, and timers connected to one another and to said various means to automatically control the timed operation of each of said means.

9. In a foundry sand reclaiming system, a continuous gravity feed line for reclaiming foundry sand, said line comprising measuring means for batch measuring the sand, dry scrubbing means for receiving the sand batches, suction means for drawing off the nes from the sand while being dry scrubbed, means for Wetting, scouring and mulling the sand, desilting means for removing organic and foreign matter from the wet scrubbed sand, means for elutriating the wet cleaned sand to grade the sand, settling means for receiving water and fines from the elutriating means, centrifuging means for dehydrating and drying the clean graded sand and discharging the resultant water into the settling means, means operable to draw 011 the water from the settling means to re-use the water in the operation of the desilting means to reduce Water consumption, and timing means connected with and automatically governing the operation of the sand treating means in timed sequence depending upon the timing of the longest step in the sequence.

10. A used foundry sand reclaiming system including in combination a dry cleaning means, means for removing fines from the sand while being dry cleaned, a series of wet cleaning and grading means, centrifuging means for receiving the cleaned graded sand and drying the same for re-use, and a plurality of automatic timers connected to one another and to the dry cleaning means, the wet cleaning and grading means and to the centrifuging means for independently controlling the timed operation of said means and the timing of a complete cycle of operations of the system.

ALFRED C. CHRISTENSEN. JAMES J. DVORAK.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,261,447 Barnebl Nov. 11, 1941 2,233,728 Bell Mar. 4, 1941 2,290,686 Norsfleld July 21, 1942 2,331,102 Bird Oct. 5, 1943 2,263,797 Christensen Nov. 25, 1941 2,331,135 Ovestrud Oct. 5, 1943 2,261,947 Barnebl Nov. 11, 1941 FOREIGN PATENTS Number Country Date 298,396 Great Britain Oct. 11, 1928 360,943 Great Britain Nov. 9, 1931

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