Impact scrubber

Abstract

An impact scrubber for removing coating materials from the surfaces of particulate matter such as foundry sand and the like comprises a lift tube having an inlet end and an opposite end for containing a high velocity fluidized stream of said matter, fluid injector means spaced adjacent said inlet end for carrying said particulate matter into said inlet end and forming a fluidized stream of said matter in said lift tube, movable deflector means adjacent and in communication with said opposite end for directing said fluidized stream angularly outward with respect to a longitudinal axis of said lift tube for discharging said matter therefrom, support means for rotatively supporting said deflector means for directing said discharge therefrom in a selected one of a plurality of relative rotative positions, and means for separating the coating materials removed by impact from said particulate and said particulate matter.

Description

The present invention relates to a new and improved impact scrubber for removing coating materials from particulate matter and more particularly to new and improved apparatus for reclaiming for reuse the granular materials commonly used in foundry operations such as foundry sand and the like. The present invention is an improvement over the apparatus shown and described in copending patent application, Ser. No. 332,415 filed Feb. 14, 1973, now U.S. Pat. No. 3,825,190, invented July 23, 1974, and assigned to the same assignee as the present invention.

In foundry operations granular base materials such as silica sand, zirconia sand and the like are coated with binding products, for example, clays, cereals, resins, and oils and the resulting mixture comprises foundry sand which is shaped and molded into definite shapes around patterns to form mold cavities. Molten metal is poured into the cavities as castings are made. The molding sand is subjected to direct contact with hot molten metal and the binding products which coat the granular sand base materials are oxidized and/or calcined in the molding process by the intense heat involved. In order to recondition the base material for further use in subsequent foundry operations, it is desirable to remove the oxidized coatings from the basic sand granules and subsequently prepare the sand as molding sand in suitable formulations with the necessary binding products required for a mold. The oxidized or calcined coating materials on the used molding sand granules are generally carbonaceous in nature and also are of a generally lower density than the basic sand material itself.

Accordingly, it is desirable to provide a system for removing the encrusted coating material from the sand grains in a dry, mechanical impact scrubbing process and then separate the lighter weight coating materials from the basic sand or particulater matter so that the clean sand may then be reused in subsequent molding operations after reformulation with the necessary binders.

The impact scrubber of the present invention is a self-contained, highly efficient unit, requiring a relatively small floor space, and is automatically controlled to provide the desired scrubbing/cleaning action as may be required for the particulate matter being treated.

It is an object of the present invention to provide a new and improved impact scrubber for treating particulate matter such as foundry sand and the like, and more particularly it is an object of the invention to provide a new and improved scrubber of the character described which is highly efficient in operation, automatically controlled for operation and discharge and which requires a relatively small floor space per unit of capacity in comparison with prior sand scrubbers.

Another object of the present invention is to provide a new and improved impact scrubber for cleaning particulate matter having a plurality of separate impact type sand scrubbing units and means for controlling the direction of discharge from all of said units simultaneously.

Another object is to provide a sand scrubber of the character described including novel means for adjusting the application of the individual scrubbing units for the most efficient operation.

Another object of the present invention is to provide a new and improved impact scrubber for cleaning particulate matter having a novel target system for receiving the impact of the fluidized flow of matter in order to mechanically remove the calcined or oxidized coatings from the individual particles of matter.

Another object of the invention is to provide a new and improved, dry process, mechanical impact type scrubber which includes a novel system for separating the coating materials from the grains of particulate matter.

Another object of the present invention is to provide a new and improved impact scrubber having a plurality of individual lift tube scrubber units and means for automatically controlling the direction of the discharge of particulate matter for impact scrubbing or for discharge from the scrubber itself.

The foregoing and other objects and advantages of the present invention are accomplished in an illustrated embodiment, by way of illustration and not limitation, comprising a dry process, mechanical impact, scrubber for removing coating materials from the surfaces of particulate matter such as foundry sand and the like. The scrubber comprises one or more lift tubes, each having an inlet end and an opposite end for containing a high velocity fluidized stream of said matter and fluid injector means spaced adjacent said inlet end for carrying said particulate matter into said inlet end and forming a fluidized stream in said lift tube. Deflector means is provided adjacent and in communication with the opposite ends of the lift tubes for directing said fluidized stream angularly outward with respect to the longitudinal axes of said lift tubes for discharge therefrom. Support means is provided for rotatively supporting said deflector means for directing said discharge therefrom in a selected one of a plurality of relative rotative positions. Means is provided for separating the coating materials broken away from the grains of particulate matter and the cleaned grains of particulate matter so that the particulate matter may be used again.

For a better understanding of the invention reference should be had to the following detailed description taken in conjunction with the drawings, in which;

FIG. 1 is an elevational view with portions shown in section of a new and improved impact scrubber for treating particulate matter constructed in accordance with the features of the present invention.

FIG. 2 is a transverse, horizontal cross sectional view taken substantially along lines 2--2 of FIG. 1;

FIG. 3 is another transverse horizontal cross sectional view taken substantially along lines 22 of FIG. 1 but showing the scrubber units in a discharging position.

FIG. 4 is another transverse cross sectional view taken substantially along lines 4--4 of FIG. 1; and

FIG. 5 is an enlarged fragmentary vertical sectional view taken substantially along lines 5--5 of FIG. 4.

Referring now more particularly to the drawings therein is illustrated a new and improved impact scrubbing apparatus for the treatment of particulate matter such as foundry sand and the like and constructed in accordance with the features of the present invention. The apparatus as a whole is referred to by the reference numeral 10 and includes an upstanding cylindrical housing 12 having a circular base 14. At the upper end of the housing 12 there is provided a hopper 16 for holding and receiving the sand or other particulate matter to be processed by the scrubber. The hopper 16 includes a frustro-conical bottom wall 18 having a circular shaped opening 20 at the lower end for feeding the particulate matter downwardly into a cylindrical, intermediate section of the housing referred to by the numeral 22 and separated from an upper or hopper section of the housing by an annular wall 24. The intermediate or discharge section 22 of the housing is similarly separate from a lower housing section 26 by an annular wall 28.

In accordance with the present invention, the scrubber 10 includes a plurality of vertically extending, impact type, lift tube scrubbing assemblies or units generally indicated by reference numeral 30. As shown in FIG. 1, each scrubber unit extends upwardly from the lower housing section 26 through an opening in the annular wall 28 and projects upwardly to the intermediate section 22 of the housing. In the lower housing section 26, the scrubber units 30 are disposed on diametrically opposite sides of an upstanding, cylindrical, air plenum chamber 32 which is centrally positioned in the housing 12 and extends between the circular bottom plate 14 and the circular wall 28. The plenum chamber 32 is supplied with a high volume flow of pressurized air from a suitable source such as a "Rootes" type blower or equivalent via an inlet duct 34 which extends radially outwardly of the plenum chamber and passes through an appropriately shaped opening formed in the wall of the cylindrical housing 12.

Each of the lift tube scrubber units 30 includes a cylindrical outer shell 36 having an annular mounting flange 38 adjacent the upper end secured to the wall 28 in concentric relation with a circular opening therein by suitable fasteners such as removable bolts 39. At the lower end each shell 36 is provided with an annular lower end flange 40, which flanges provide support for convergent type, high velocity, injection nozzles 42 as shown in FIG. 1. Each nozzle 42 is removably attached to its supporting flange 40 and is connected at its lower end via a coupling 44 with a conduit structure in communication with the central plenum chamber 32 for receiving pressurized air. As illustrated, the conduit structure includes an intermediate section 46 coupled at its lower end with a control valve 48 which in turn is interconnected with the central plenum chamber 32 by a supply elbow 50. The supply elbows radiate outwardly from the plenum chamber and each elbow has a lower, horizontal leg 50a and a vertical leg 50b having its upper end connected to the lower end of a control valve 48.

In order to individually control and regulate the flow of pressurized air from the central plenum chamber 32 to the nozzle 42 of each scrubbing unit 30, the individual valves are adjusted and pressure gauges 52 connected to short pipe nipple sections 46 are provided for guiding the operator in adjustment of the valves to secure the desired rate of flow of fluid through the nozzle. The central air plenum chamber 32 provides a high volume source of pressurized air at relatively low pressure (inches of water) for supplying the nozzles 42 of the lift tube scrubber units 30 and the valves 48 are utilized for individually controlling the respective units in accordance with the pressure gauge readings from the gauges 52.

After periods of inactivity of the scrubber 10, sand and other materials tend to collect in the lower end of the shells 36 and often tends to plug the nozzles 42 to such a degree the adequate air flow is prevented when the next start up is attempted. A high pressure compressed air starting system is provided and this system includes an upstanding compressed air injector 54 mounted in each elbow 50 and designed to inject high pressure (up to 100 psi) starting air into the material collected in elbows to clear the passage through the nozzles 42 and the lower end of the shells 36. The air injectors are connected to a common compressed air supply manifold 56 and a control valve 58 is provided. The manifold is connected to a suitable source of high pressure air.

Each cylindrical shell 36 is formed with an elongated, axially extending access opening in the outer side wall thereof and these access openings are sealed during operation by means of removable or hingedly attached access doors 60. The doors permit servicing of the interior of the shells 36 and clean out of the units if required.

In accordance with the present invention, each lift tube unit 30 includes an elongated, vertical lift tube 62 aligned in coaxial arrangement with an adjacent air supply nozzle 42 and spaced vertically above the outlet of the nozzle by an adjustable distance D. The lower or inlet end of each lift tube 62 is provided with a replaceable annular inlet ring 64 having a slightly tapered internal bore and the ring is adapted to receive and guide a fluidized flow of particulate matter into the tube as it is entrained upwardly by the air jet issuing from the nozzle outlet. The high velocity air flow moving upwardly in the lift tubes forms a high velocity turbulent fluidized flow of particulate matter and air. During the entrainment of the particulate matter in the air jet adjacent the inlet end of the lift tube and during the upward turbulent flow within the lift tube, intense interaction between the individual particles of particulate matter takes place in the form of repeated random collisions. These collisions or impacts aid in breaking up and removing the encrusted coating materials on the sand grains and this material along with the sand is carried upwardly in the turbulent stream.

The lift tubes 62 are adjusted in precise coaxial alignment with the nozzles 42 by means of radial spacers 66 mounted on the shells 36 and adjustable exteriorly thereof. The spacers are provided at upper and lower levels on the shells as shown and at each level a plurality of spacers are provided (three or four) in order to permit precise axial alignment of the nozzle and lift tube.

The circular wall 28 is formed with circular openings 28a spaced radially outward of the center and in coaxial alignment with the respective shells 36 of the lift tube assemblies 30. These openings are substantially the same diameter as the internal diameter of the shells 36 and the particulate matter from the chamber section 22 flows downwardly into the shells around the lift tubes 62 for pick up by the air jets issuing upwardly from the outlet of the nozzles 42.

The elongated side access openings in the shells 36 permit the lift tubes 62, nozzles 42 and inlet ring 64 to be serviced on replaced without complete dismantling of the scrubber units 30. The lower section 26 of the housing 12 is provided with relatively large, vertical, elongated access openings or slots 68 which slots are large enough to permit easy insertion and withdrawal of the complete lift tube unit 30 in both an assembled or disassembled condition.

At the upper end, each lift tube 62 is interconnected with a flow deflector and impact assembly generally indicated by the reference numeral 70. The deflector assembly includes a cylindrical outer shell 72 and a centrally positioned coaxial lift tube extension 74 connected to the upper end of the lift tube 62 by a coupling 76. Each lift tube extension 74 is supported within its shell 72 by means of a plurality of vertical rib members 78 extending radially outward from the lift tube extension at right angles to one another as best shown in FIGS. 2 and 3.

Adjacent the upper end, each lift tube extension 74 is formed with an annular end wall 80, which wall forms an outer portion of an impact target for the upwardly moving, fluidized particulate matter carried in the lift tube 62. As best shown in FIG. 5 the end wall 80 is formed with a central aperture therein in order to accommodate the lower end of an elongated support rod 82 extending upwardly therethrough. As best shown in FIG. 1, the support rods 82 project upwardly through openings provided in the circular wall 24 between the intermediate housing section 22 and an upper housing section adjacent the level of the hopper 16. At the lower end, each support rod is provided with a large cylindrical head 84, which head forms the central portion of an impact target for the upwardly moving fluidized particulate matter if the lift tube extension 74.

As best shown in FIG. 5, the upwardly flowing particulate matter forms a pad of particulate matter in the upper end of the lift tube extension and the pad of matter itself protects the structural members 80 and 84 from excessive wear. The upwardly flowing matter impacts or strikes the pad of matter formed at the upper end of the lift tube and this causes further the oxidized coatings material to be knocked off of the individual grains of the particulate matter. As shown by the arrows in FIG. 5, the material rebounds downwardly and is deflected outwardly by the upwardly moving oncoming fluidized stream into a radially extending horizontal discharge tube 85 forming an elbow with the lift tube extension and having an open outer end adapted to discharge the impacted material which now includes relatively clean grains of particulate matter and the lighter in weight coating material which is knocked off or separated from base matter.

As best shown in FIG. 5, the outer, open ends of the discharge tubes 85 are adjacent the outer surface of the cylindrical deflector shells 72. From the foregoing it will be seen that the individual granules of particulate matter flowing upwardly in the lift tube units 30 are impacted against one another again and again. Moreover, repeated impacts occur as the matter enters the lower inlet rings 64 on the lift tubes 62 as well as during the upward flow in the tubes. Further impacts occur as the matter strikes the pad of material formed at the closed upper end of the lift tube extension 74. Moreover, a further impact zone is developed adjacent to the mouth of the discharge tube 85 where the downwardly rebounding material collides with the upwardly moving matter before it moves outwardly toward the outer end of the discharge tubes.

As best shown in FIGS. 1 and 2 when all four of the deflector assemblies 70 of the respective lift tube scrubber units 30 are arranged with the discharge tubes 85 directed radially inwardly toward the center of the housing 12, an intense, impact scrubbing zone is formed in center of the housing section 22. The heavier particles of material that are discharged from the tubes 85 in a horizontal direction as shown by the arrows A gravitate downwardly onto a conical structure 86 centered above the air plenum chamber 32. The sloping surfaces of the cone 86 direct the material outwardly toward the circular openings 28a in the wall 28 and the material then flows downwardly into the shells 36 of the respective scrubber units 30 to be recycled in the scrubbing process. The impact scrubbing zone centered above the cone 86 may be formed by the impingement of moving material streams impacting one another from opposite directions as described and set forth in the foregoing copending United States patent application, or in the alternative, a removable target structure 88 may be provided. The target structure includes pairs vertically extending impact vanes 90 which are secured along their inner vertical edges to a central hollow tube 92. The tube 92 is adapted to be restrained by upstanding support stud 94 which is secured to the apex of the cone 86. For lifting the target from the stud a handle 96 is provided at the upper end of the tube 92.

As shown in FIGS. 1 and 2 when the discharge tubes 85 are directed radially inwardly the flow of material (arrows A) strikes the convergent surfaces of the impact vane 90 and the collisions of particles with the vane surfaces causes another intense scrubbing zone to develop immediately above the cone 86. In this region additional coating materials remaining on the grains are knocked off and removed by the repeated impacts. The heavier grains of particulate matter gravitate downwardly onto the sloping surfaces of the cone 86, and are directed into the shells 36 of the respective scrubber units 30 through the openings 28a in the wall 28. In this manner the particulate matter being handled by the scrubber 10 is continuously recycled through the individual lift tube scrubber units 30 for a selected period of time until the desired degree of cleaning action is obtained.

Each individual deflector 70 is supported by a rod 82 and each rod is provided with an enlarged head 84 at the lower end. The deflectors are rotatable from the normal operational position of FIG. 2 to the discharge position of FIG. 3 wherein the discharge tubes 85 are directed radially outwardly away from the center of the housing 12. Each support rod is keyed to its deflector for rotation therewith by a cross pin 98 (FIG. 5) which extends through slots 74a provided on diametrically opposite sides of the lift tube extension 74 at the upper end as shown in FIG. 5. When the support rods 82 are rotated 180.degree. from the position shown in FIG. 2, the discharge tubes 85 of the respective deflectors 70 will be rotated a like amount to direct the discharge of material outwardly as shown in FIG. 3 by the arrows A.

With the deflectors 70 positioned in the discharge position as shown in FIG. 3 the fluidized stream of particulate matter and coating materials separated therefrom are directed outwardly through the housing wall into a plurality of separate discharge boxes secured to the outer surface of the housing 12 and referred to generally by the reference numeral 100. Each discharge box is positioned adjacent an elongated vertical slot 102 formed in the wall of the scrubber housing 12 and aligned with the outlet end of the discharge tubes 85 when the deflector assemblies 70 are in the discharge position as shown in FIG. 3. As best shown in FIG. 1, the slots 102 are longer in vertical dimension than the diameter of the discharge tubes 85 and the vertical adjustment of the lift tubes provided to vary the distance D changes the level of the discharging streams issuing from the outlet ends of the discharge tubes 85 into the respective discharge boxes 100. The slots 102 are slightly larger in width or horizontal dimension than the outside diameter of the discharge tubes 85 so the precision alignment is not required when rotating the deflector assemblies 70 into the discharge position as shown in FIG. 3.

Each of the discharge boxes 100 includes a pair of opposite side walls 104, an outside wall 106, a top wall 108 and a bottom wall 110 and the outer wall of the intermediate section 22 of the scrubber housing 12 provides an inside wall for the discharge boxes. In order to protect the outer side walls 106 of the discharge boxes from excessive wear and abrasion from the discharging materials of the discharge tubes 85 and further to provide a secondary impact zone for separation of the lighter weight coating materials from the base particulate matter, each discharge box is provided with a relatively thick, heavy, hanging baffle 112 formed of resilient material such as rubber and the like and extending downwardly through a slot formed in the top wall 108. The baffles hang freely and are positioned directly in front of the discharging streams from the discharge tubes 85. Each hanging baffle includes an enlarge bulbous upper end portion for supporting the baffle from the top wall of the discharge box and the lower end portion of the baffle is free to swing and may be deflected by the high velocity stream of material impinging thereon. Within each discharge box 102 there is provided a pair of adjustable baffles 114 and 116 supported on shafts rotatably controllable from the outside of the boxes to achieve desired slopes for directing the heavier, cleaned sand grains or other particulate matter downwardly towards the lower end wall 110. A fixed baffle 118 is also provided to guide the downwardly flowing material as it drops from the hanging resilient baffle 112 onto the adjustable baffle 114. The material sifts downwardly in a falling stream or curtain from the lower edges of the baffles as it moves toward the lower end of the boxes. The thickness of the streams of material is controlled by the adjustable baffles. Material reaching the bottom wall 110 flows through a bottom discharge outlet 110a via a short pipe section 122 into the upper end of a pinch valve 120. The lower end of the pinch valves 120 maybe interconnected to a common discharge manifold 124 so that the cleaned particulate matter from the scrubber 10 may be discharged or transported via a pneumatic transport system or the like such as that shown in U.S. Pat. No. 3,297,366. The pinch valves 120 may be of the type shown in this patent and are normally closed until a sufficient amount or head of material has been collected in the upper portion of the valve housing. The flexible sleeves then open to discharge the material into the pneumatic transport system. The valves may also be positively controlled to open and close.

In order to separate the lighter in weight coating materials removed from the grains or base particles of the particulate matter being treated, each discharge box 100 is provided with an atmospheric damper assembly 122 which permits air to enter the lower end of the discharge box through an opening 104a in one of the side walls spaced below the fixed baffle 118 as best shown in FIG. 1. Air entering through the dampers 122 passes upwardly in a tortuous path moving upwardly through the downwardly flowing curtain of material discharged from the lower edges of the respective baffles 114, 116 and 118. This upwardly moving draft of air current carries the lighter weight materials upwardly to discharge outlets 128 formed on the upper walls 108. The discharge outlets 128 on the top walls 108 of the discharge boxes 100 are connected to a suction manifold 130 and a discharge fan 132 is provided to provide the necessary draft for removal of the fine materials as shown in FIGS. 1, 2 and 3. The amount of fines removed can be controlled by adjusting the negative pressure in the discharge boxes. It will thus be seen that the baffles 112 in discharge boxes 100 provide yet another impact zone and the air draft therein provides means for separating the cleaned sand grains from the lighter weight coating materials that is knocked off of base particulate matter. The cleaned sand is collected in the lower end of the discharge boxes 100 for delivery by a suitable transport system or the like to another location for further use.

In accordance with an important feature of the present invention, as previously described, the lift tube 62, ring 64 and deflector assembly 70 of each individual scrubber unit 30 is supported by an individual elongated support rod 82 having an enlarged head 84 at the lower end. The rods project upwardly through openings 24a in the circular wall 24 (FIG. 5) into the upper portion of the housing adjacent the level of the hopper 16. Each support rod 82 is keyed to a lift tube extension 74 by means of a cross pin 98 so that rotation of a support rod will cause the deflector assembly 70 to rotate therewith.. Rotation of all of the support rods 82 by 180.degree. from the position of FIG. 2 causes the discharge assemblies 70 to rotate in unison until the discharge tubes 85 are directed outwardly in the discharge position as shown in FIG. 3. In order to limit and control the amount of rotation, of the discharge assemblies 70 at least one shell 72 is provided with a pair of upstanding limit stops 134 and 136 secured to the inside surface as best shown in FIGS. 1, 2 and 3. In order to control the flow of sand or other particulate matter into the scrubber from the discharge opening 20 of the hopper 16, there is provided a conical valve member 138 adapted to open and close the discharge opening to regulate the flow. The conical valve member 138 is mounted on the outer end of a cylinder rod 140a of a vertically positioned, fluid operated valve cylinder 140. The lower end of the cylinder 140 is supported on a channel-like base 142 positioned in the intermediate housing section 22 and supported from the upper circular wall 24 at opposite ends by depending brackets 144 as best shown in FIG. 1. As shown in FIGS. 2 and 3, opposite side edges of the support channel structure 142 cooperate with the upstanding limit stops 134 and 136 on the right hand (FIG. 1) deflector assembly 70 to provide for alignment of the discharge tubes 85 of the respective deflector assembly in the normal operating position (FIG. 2) or the discharge position (FIG. 3).

Referring now more particularly to FIG. 5, the support rods 82 of the respective deflectors 70 are connected by turnbuckles 83 with upper ends 87 which extend upwardly through the openings 24a in the circular wall 24. The upper end portion of each upper rod is slidably disposed in a pair of flanged bearings 146 spaced on opposite sides of a chain sprocket 148, which is secured by set screws 150 to a sleeve 151 attached to the support rods 87 by a removable pin 153. The lower flanged bearing 146 is attached to the upper surface of the circular wall 24 and the upper flanged bearing is attached to the upper surface of a circular support plate 152 supported in parallel, spaced apart relation above the circular wall 24 by a plurality of support post assemblies 154. An endless roller chain 156 is entrained around all of the several sprockets 148 in order to drivingly rotate all of the support shafts 82 in unison and thereby rotate all of the deflector assemblies 70 when it is desired to move the deflectors from a discharge to an operating position or vice versa.

As shown in FIG. 4, the roller chain 156 is passed around all of the sprockets 148 of the respective support rods 82 and in addition, the chain is passed around a pair of idler sprockets 156 into driving engagement with a single drive sprocket on the output shaft of a fluid motor 160. The fluid motor 160 is reversible and is supplied from a source of compressed fluid. A valve system is used to operate the motor in reverse directions in order to rotate the deflector assemblies 70 back and forth between the normal operating position and the discharge position of FIGS. 2 and 3. Normally the fluid motor is actuated to rotate the sprocket 158 in a given direction for a selected time interval, which interval is slightly longer than the time required to rotate the deflector assemblies through 180.degree. from one position to the other. Rotation of the deflectors is stopped by engagement of one or the other stop members 134 or 136 with the side of the support channel 142 as previously described.

When it is desired to adjust the spacing distance D between the upper end of the nozzle 42 and its respective entrance ring 64 on the lift tube 62, the set screw 150 on the sprocket 148 is loosened and the support rod is moved up or down as desired to provide the proper spacing D. After the spacing is set the set screw 150 is retightened to again key the sprocket to the support rod.

The scrubber 10 provides means for adjusting the individual clearance distance D between the lift tube entrance ring and the nozzle in each of the scrubber units 30 and in addition the system provides for simultaneously rotating all of the deflector assemblies 70 of the respective scrubber units to the normal operating or the discharge position as desired.

As shown in FIG. 1, relatively large access slots 162 are provided in the housing wall 12 so that the chain, sprockets, bearings and set screws may be serviced and adjusted as described. In addition, as shown in FIGS. 2 and 3 the intermediate section 22 of the housing 12 is formed with relatively large access openings 164 in the side wall in order to permit servicing or replacement of the individual deflector assemblies 70. These may be removed completely from the housing 12 by detachment from the respective lift tubes 62 when the couplings 76 and the set screws 150 are loosened. The access openings 162 are large enough in width and height to permit easy service or complete withdrawal of a deflector assembly 70. During normal operation, arcuate cover plates 164 are provided to cover the access openings 162 and confine the particulate material and dust within the intermediate section 22 of the housing 12.

Although the present invention has been described with reference to a single illustrative embodiment thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this invention.

Claims

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. An impact scrubber for removing coating materials from the surfaces of particulate matter such as foundry sand and the like comprises at least one lift tube unit having a lift tube with an inlet end and an opposite end for containing a high velocity fluidized stream of said matter, fluid injector means spaced adjacent said inlet end for carrying said particulate matter into said inlet end and forming a fluidized stream of said matter in said lift tube, fluid stream deflector means adjacent and in communication with said opposite end of said lift tube, means mounting said deflector means for rotation around a longitudinal axis of said lift tube, said deflector means including a discharge tube for directing said fluidized matter in a single stream angularly outward with respect to said longitudinal axis of said lift tube at different rotative positions, and means for rotating said deflector means for directing said discharge tube in a selected one of a plurality of relative rotative positions.

2. The scrubber of claim 1 including means for supporting said lift tube in a selected one of a plurality of different axial positions relative to said injector means wherein said spacing between said inlet end and said injector means may be selectively adjusted.

3. The scrubber of claim 1 including a plurality of said lift tube units, a common housing for said units having a central axis spaced between said units, said means for rotating said deflector means operable to position a discharge tube for each lift tube in a selected direction facing toward said central axis or away from said axis, and separator means including enclosures spaced on opposite sides of said housing for receiving fluidized streams of material discharged from said deflector means when positioned to discharge away from said central axis, said separator means further including means for separating said particulate matter and said coating materials removed from the surfaces of said particulate matter.

4. The scrubber of claim 3 wherein said supporting means includes means for supporting each of said lift tubes in selectively adjustable axial positions relative to their respective injector means wherein said spacing between said inlet end and said injector means of each unit may be varied.

5. The scrubber of claim 3 wherein said deflector means of each unit includes a lift tube extension having a closed upper end and a discharge tube angularly extended outwardly from said lift tube extension and in communication therewith at a level below said closed end.

6. The scrubber of claim 5 wherein each unit includes removable coupling means for interconnecting a lower end of said lift tube extension and said opposite end of said lift tube.

7. The scrubber of claim 5 wherein said housing includes discharge openings formed on opposite sides in communication between said discharge tubes and said separator enclosures when said deflector means are rotated to discharge in opposite directions away from said central axis.

8. In an impact scrubber for removing coating materials from the surfaces of particulate matter such as foundry sand and the like, an enclosure, flexible target means in said enclosure, inlet means adjacent an upper level of said enclosure for directing a flow of said matter and material against said target means, said target means including a piece of flexible material supported from an upper end portion to hang generally vertically in said enclosure with a freely deflectable lower end portion spaced in front of said inlet meaans, baffle means in said enclosure below said inlet means for forming a curtain of downwardly flowing matter and material and draft means for moving a flow of air through said curtain for carrying at least a portion of said coating materials upwardly away from said particulate matter.

9. The appartus of claim 8 wherein said draft means includes an air inlet opening in said enclosure spaced below said baffle means and suction means in communication with said enclosure above said baffle means for inducing air pass into said air inlet opening and through said curtain of material flowing downwardly of said baffle means.

10. The apparatus of claim 8 wherein said baffle means includes at least one sloped baffle and means for adjustably selecting the angle of slope thereof.

11. An impact scrubber for removing coating materials from the surfaces of particulate matter such as foundry sand and the like comprises at least one lift tube unit having a lift tube with an inlet end and an opposite end for containing a high velocity fluidized stream of said matter, fluid injector means spaced adjacent said inlet end for carrying said particulate matter into said inlet end and forming a fluidized stream of said matter in said left tube, deflector means adjacent and in communication with said opposite end for directing said fluidized stream angularly outward with respect to a longitudinal axis of said lift tube for discharge therefrom, support means for rotatively supporting said deflector means for directing said discharge therefrom in a selected one of a plurality of relative rotative positions, and means for separating said coating materials and particulate matter including an enclosure for receiving said fluidized stream from said deflector means, flexible target means in said enclosure, inlet means adjacent an upper level of said enclosure for directing a flow of said matter and material against said target means, baffle means in said enclosure below said inlet means for forming a curtain of downwardly flowing matter and material and draft means for moving a flow of air through said curtain for carrying at least a portion of said coating materials upwardly away from said particulate matter.

12. The apparatus of claim 11 wherein said enclosure includes a side wall, said inlet means adapted to direct a horizontal flow of material through said side wall, and said target means comprises a piece of flexible material supported from an upper end portion to hang generally vertically in said enclosure with a freely deflectable lower end portion spaced in front of said inlet means.

13. The apparatus of claim 11 wherein said draft means includes an air inlet opening in said enclosure spaced below said baffle means and suction means in communication with said enclosure above said baffle means for inducing air pass into said air inlet opening and through said curtain of material flowing downwardly of said baffle means.

14. The apparatus of claim 11 wherein said baffle means includes at least one sloped baffle and means for adjustably selecting the angle of slope thereof.