US3567139A

US3567139A - Method of mulling

Info

Publication number: US3567139A
Application number: US735393A
Authority: US
Inventors: Karl H Andrae
Original assignee: Jeffrey Galion Inc
Current assignee: Jeffrey Galion Manufacturing Co; Jeffrey Galion Inc
Priority date: 1963-12-27
Filing date: 1968-06-07
Publication date: 1971-03-02
Anticipated expiration: 1988-03-02

Abstract

Method of mulling material in which the material is continuously delivered to and discharged from a receptacle. The material is dispersed in the receptacle and is distributed on the inner cylindrical mulling surface of the receptacle to be mulled on the mulling surface as the material continuously flows through the receptacle.

Description

United States Patent Inventor Karl l-l. Andree [56] References Cited Columbus, Ohio UNITED STATES PATENTS P 469,145 2/1892 Hughes 241 /130x 1 rs N 33 936 D 27 1963 507,432 10/1893 Griffin..... 241/129x g' gygu gg 3 1 1 1,706,417 3/1929 Simpson.. 241/124x Patented Mat 2 2,575,410 11/1951 Davis 241/98X Assignee Jeffrey Galion Manufacturing Company Emmme'Dnald Kelly Att0rneyDavid Young METHOD OF MULLING 5 Claims, 11 Drawing Figs.

US. Cl 241/ 17, ABSTRACT: Method of mulling material in which the materi- 241/29 al is continuously delivered to and discharged from a receptalnt.Cl ..B02c 15/08, cle. The material is dispersed in the receptacle and is dis- B02c 21/00 tributed on the inner cylindrical mulling surface of the recep- Field of Search 241/15- tacle to be mulled on the mulling surface as the material con- 18, 22, 29, 30, 42, 43, 98, 124, 129, 130 tinuously flows through the receptacle.

I 1 l I 37 i 34 F 1' E f, i U

i i i Q1 I l I i ,1L 31 I J 2 i) 7 i E I I F 24 e 1 i i 23 1 1 u 1 PATENTEDHAR 2M1 3567;139

SHEET 1 BF 4 INVENTOR, KARL HAN DRAE,

HTT'Y METHOD OF MULLING This application is a division of application Ser. No. 333,936, filed Dec. 27, 1963, Pat. No. 3,430,874, issued Mar. 4, I969.

The instant invention relates to the mulling of materials, for example as is practiced in foundry operation in respect to the preparation of sand for making molds, and more particularly, to an improved method of mulling.

This invention has application to the treatment of materials by mulling, for example, the mulling of sand in a foundry to place the same in suitable condition for use in making molds in metal casting operations. The mulling of the sand may involve new sand which has not previously been used in making molds, recirculated sand which has been used in molds and is circulated in the foundry system for reuse, or a combination of the two. In any of these cases it is required that the sand be mulled, which involves adding to the sand and combining therewith certain ingredients, particularly water and bonding agents. In the mulling operation, it is desired that these ingredients be uniformly combined with the mass of sand, and in an ideal operation each grain of sand is completely and uniformly coated with the added ingredients, whereby the mass of sand discharged from the mulling operation has the necessary bonding characteristics, such that it may be formed into molds into which hot molten metal may be poured.

The mulling of the sand is essentially a pressing, kneading and mixing operation in which the sand and the added ingredients are constantly being pressed, kneaded and mixed until the added ingredients are uniformly dispersed in the mass of sand, and the grains of sand are each coated with the bond- 2 ing materials. In mulling operations, in which recirculated sand is being operated upon, such sand is usually very hot as the result of being in contact with hot molten metal, and is far hotter than is desired for the mulling operation or for the formation of molds. In such case it 'is necessary that the sand be cooled, and this may be accomplished during the mulling operation by circulating air through the sand, in addition to the tempering water that is added. Also in connection with the preparation of the sand for the making of molds, it is desired that the sand be aerated, which consists essentially of breaking up any lumps in the sand and placing the massof sand in a loose, uniform condition, in which it may be readily and uniformly packed around a pattern in the process of making a mold with such sand. l

It is an object of the instant invention to provide an improved continuous method for the preparation of materials by mulling, for example, sand to be used in the making of molds.

It is. a further object of the instant invention to provide an improved method of continuously mulling materials, in which the material is dispersed around an axis and distributed over a cylindrical mulling surface as the material continuously flows in a longitudinal direction.

Other objects of the invention will appear hereinafter, the novel features and combinations being set forth in the appended claims.

' In the drawings:

FIG. 1 is an elevational view of an exemplary installation of thecontinuous muller of the instant invention;

FIG. 2 is an elevational view of the continuous muller installation looking towards the feed or upstream end of the continuous muller;

FIG. 3 is a plan view of the continuous muller installation;

FIG. 4 is an elevational view, partially in section, of the discharge end of the continuous muller; FIG. 5 is a longitudinal, elevational view of the continuous muller, partially in section;

FIG. 6 is a transverse sectional view of the continuous muller, taken on the line 6-6 in FIG. 5;

FIG. 7 is a partial transverse sectional view of the continuous muller, showing a typical mulling assembly, taken on the line 7-7 in FIG. 5;

FIG. 8 is an elevational view of a typical mulling assembly, viewed from the line 8-8 in FIG. 7;

FIG. 9 is a sectional view of a typical mulling assembly, taken on the line 9-9 in FIG. 7;

FIG. 10 is an elevational view of the intake accelerating plow, viewed from the line 10-10 in FIG. 6; and

FIG. 11 is an elevational view of the sweeper blade, viewed from the line 11-11 in FIG. 5.

Referring to the drawings, and particularly FIGS. 1, 2 and 3, there is illustrated therein an exemplary installation of a continuous muller 20 that is constructed in-accordance with this invention. The muller installation illustrated herein is such as would be appropriate in a foundry, and the material treated in such muller installation is foundry sand to be used in the making of molds. In such installation the continuous muller 20 is mounted on a supporting base 21, which may be fabricated from steel plate and structural iron members. The supporting base 21 has a raised platform 22 at one end, on which there are secured a motor 23 and a reducer 24. The motor 23 is connected to the reducer 24 by a suitable torque coupling 25, and the reducer is connected to the continuous muller by a suitable drive coupling 26. The continuous muller 20 is so constructed that the drive may be applied to either end thereof.

A feed chute 27 is secured to one end of the continuous muller 20, this being the feed end or upstream end of the apparatus. The feed chute 27 is constructed in the manner of a hopper, and the material delivered into the feed chute 27 flows therefrom into the continuous muller 20. A belt conveyor 28 is placed with its head pulley 29 above the feed chute 27, in position to discharge material from the belt conveyor 28 into the feed chute 27. The sand which is to be treated in the continuous muller 20, is delivered thereto by the belt conveyor 28. Preferably, the belt conveyor 28 is enclosed in a housing 30 to reduce the incidence of dust from the sand that is carried by the belt conveyor 28. The housing 30 has an open end which overlies the top of feed chute 27 and through which material discharges into the feed chute 27. The housing 30 is secured to the top of the feed chute 27 by a plurality of bolts, or like securing means, passed through like flanges 31 formed on the feed chute 27 and housing 30.

Above the conveyor housing 30 there is mounted a screw feeder 32 having a hopper 33, in which there is placed a quantity of bonding material or other ingredient to be added to the sand and to be combined therewith in the mulling operation.

The screw feeder 32 includes a cylindrical feeding conduit through which there extends a screw 35. The bonding material stored in the hopper 33 is fed therefrom by the screw 35 to the open end of the cylindrical feed conduit 34, whence the bonding material discharges through an opening 36 formed in the top of the conveyor housing 30 onto the belt conveyor 28. The rate of delivery of the bonding material by the screw feeder 32 may be controlled by suitable means governing the speed of operation of the screw feeder 32, which ultimately controls the proportion of bonding material added to the sand that is being delivered to the continuous muller 20. Only one screw feeder 32 is shown in the drawings for illustrative purposes. It will be understood, however, that more than one screw feeder 32 may be utilized; for example where it is desired to add more than one ingredient to the sand, one screw feeder 32 may be utilized for each ingredient to be added to the sand.

Within the conveyor housing 30 there is a transversely extending pipe 37, which has a plurality of downwardly directed perforations along its length overlying the belt conveyor 28. The pipe 37 is connected to a source of water, and the water discharges from the pipe perforations to deliver tempering water to the sand as it is fed to the continuous muller 20 by the belt conveyor 28. A suitable valve is preferably included in the pipeline for regulating the amount of tempering water delivered to the sand by the pipe 37.

The sand that is delivered to the continuous muller 20 flows through the apparatus in a stream away from the feed or upstream end of the continuous muller 20 and towards the discharge or downstream end thereof. As the sand flows downstream through the continuous muller 20, it is mulled within the apparatus and finally discharges from the continuous muller 20 at the discharge or downstream end thereof, at

which there is provided a discharge chute 38 for the discharging sand. In the exemplary continuous muller installation illustrated herein, a belt conveyor 39 is disposed below the discharge chute 38 to continuously receive and remove the mulled sand as it is discharged.

The exemplary continuous muller installation as described thus far, is customarily included in a complete foundry system. The belt conveyor 28 would have its tail end disposed at a position in the foundry to receive the sand that is shaken out of the molds. Such sand is then moved by the belt conveyor 28 to the continuous muller 20. It will be understood that new sand may also be delivered to the belt conveyor 28 for mulling such sand, either combined with the sand that has been previously used, or as new sand alone.

The belt conveyor 39 may extend from the continuous muller to a position in the foundry at which the mulled sand is delivered to suitable storage hoppers at molding stations, from which such sand may be taken as needed for the making of molds. Of course, the continuous muller 20 may be utilized in other arrangements or installations than that illustrated herein, such illustration being merely by way of example.

The continuous muller installation may additionally include means for causing a current of air to flow through the continuous muller 20 for the purpose of cooling the sand, and additionally, for the removal of steam from the interior of the muller 20. The sand becomes quite hot after it has been used in a mold, by reason of its contact with the hot metal therein. It is desired that the sand be cooled appreciably during the mulling operation and prior to being reused in the molds. Such cooling may be accomplished in part by the addition of excess tempering water by the water pipe 37. Such excess water evaporates out of the hot sand, forming steam in the continuous muller 20. The stream may be drawn off from the continuous muller 20 by a current of air flowing through the same. At the same time, the passage of a current of cool air through the continuous muller 20 will provide some additional cooling of the sand therein.

For the purpose of causing the current of air to flow through the continuous muller 20, there is provided an air duct 40 connected to the feed or upstream end of the continuous muller. A suitable exhaust fan may be connected to the air duct 40 to draw cool air through the continuous muller 20, the air intake in this case being the discharge chute 38. In such arrangement the current of air flows from the discharge or downstream end to the feed or upstream end of the continuous muller 20, or

- stated another way, there is a countercurrent flow of air. Al-

ternatively, the current of air may flow through the continuous muller 20 in a concurrent direction, that is from the feed or upstream end to the discharge or downstream end of the continuous muller 20. In either the countercurrent or concurrent flow of air through the continuous muller 20, the air may be caused to flow through the continuous muller 20 either by being blown through the continuous muller 20 by a suitable blower, or exhausted from the continuous muller 20 by a suitable exhaust fan.

The continuous muller 20 comprises a cylindrical, drumlike receptacle 45 placed on a substantially horizontal axis, whereby the cylindrical receptacle 45 is disposed in a lateral position extending along its axis. The receptacle 45 is supported on

feet

46,47 which may be formed of steel plate that is shaped to the desired configuration and secured to the receptacle 45 in a suitable manner, as by welding. The

feet

46,47 are placed at opposite ends of the receptacle 45 for securing the continuous muller 20 to the supporting base 21, as by a plurality of bolts.

The receptacle 45 includes a cylindrical shell 48. The feed or upstream end of the cylindrical shell 48 is closed by an end wall 49, and the discharge or downstream end of the cylindrical shell 48 is closed by a similar end wall 50. Each of the

end walls

49,50 is formed of a plate having a disclike form. The cylindrical shell 48 and the

end walls

49,50 are preferably formed of steel plate, or the like, with the

end walls

49,50 being received within the ends of the cylindrical shell 48, and

being secured thereto, as by welding, whereby the receptacle 45 is a rigid, structural subassembly of the continuous muller 20. For the purpose of further rigidifying the receptacle 45, a plurality of longitudinally extending ribs 51 are secured to the outer wall of the cylindrical shell 48, as by welding. The ribs 51 preferably are radiallyv disposed on the cylindrical shell 48. At the top of the cylindrical shell 48 there are secured two apertured cars 52, one at each end thereof, in which crane hooks may be received for raising and lowering the continuous muller 20 .when it is necessary to move the same.

The receptacle 45 is provided with an opening that extends the full length thereof in an upper quadrant of the cylindrical shell 48, as best seen in FIGS. 4 to 6. The opening is illustrated as being of lesser arcuate length than however, it will be understood that the size of the opening is governed by the need for reaching inside the receptacle 45 for maintenance of the various elements of the continuous muller 20 that are contained therein. The opening is closed by a cover 55, which forms a continuation of the cylindrical shell 48, and in effect, comprises the cylindrical shell 48 when the cover 55 is in its closed position, as seen in FIGS. 4 to 6.

The cover 55 is connected to the receptacle 45 at each end thereof by a hinge 56 having a longitudinally extending axis, whereby the cover 55 may be readily raised to its open position 57, as shown in phantom lines in FIG. 4. To facilitate raising the cover 55, there may be provided a pneumatic cylinder 58 with its cylinder end pivotally secured to the end wall 50 on a bracket 59, with a pin 60 by which the pival connection of the cylinder 58 to the bracket 59 is effected. The piston rod 61 of the cylinder 58 has a clevis 62 at its upper end by which it is connected to a depending ear 63 with a pivot pin 64. The ear 63 is secured to the cover 55, and the pin 64 forms a pivotal connection between the piston rod 61 and the cover 55. A control valve 65 is secured to the end wall 50 and is connected to the pneumatic cylinder 58 for operating it to raise and lower the cover 55 as desired.

The cover 55 has a tail plate 66 which is secured thereto at one side and extends from approximately the upper edge of the cover 55 in a circular arc having its center on the axis of hinge 56. The tail plate 66 is a planar element disposed adjacent to the end wall 50. At the end of the tail plate 66 there is secured a rectilinear guide 67 within which there is slidably supported a bolt 68. Below the tail plate 66 there is provided an arcuate track 69 which is concentric with the tail plate 66. When the cover 55 is moved to its open position'57, the bolt 68 moves along the track 69, in contact with the top of the same, until the cover 55 has reached its fully opened position, at which the rectilinear guide 67 is beyond the end of the track 69 and the bolt 68 drops down past the end of the track 69. The arcuate length and position of the track 69 are determined in accordance with the length of the arc through which the cover 55 is swung to raise it to its fully opened position, so that when the cover 55 is at its fully opened position, the bolt 68 drops past the end of the track 69.-The bolt 68 and the track 69 together provide a positive stop which prevents the cover 55 from being inadvertently lowered or accidentally falling, and constitutes a safety device which is desirable by reason of the weight of the cover 55.

The bolt 68 has a pin 70 extending through a slot 71 in the rectilinear guide 67. By means of the pin 70, the bolt 68 may be withdrawn into the rectilinear guide 67, and the cover 55 then lowered by reverse operation of the pneumatic cylinder 58. Once the bolt 68 has passed rearwardly beyond the end of the track 69, and into engagement with the top of the track 69, it is maintained in withdrawn position by the track 69.

At the lower edge of the receptacle opening there is a longitudinally extending locking bar 74 which projects outwardly from the cylindrical shell 48. The lower edge of the cover 55 has a like, longitudinally extending locking bar 75 which is secured thereto and is disposed to be in parallel position to the locking bar 74 when the cover 55 is in its closed position. The cover 55 is locked by special locking bolts 76, several of which are disposed along the locking bars 74,75 to secure the locking bars 74,75 to each other. Each locking bolt 76 includes a boss 77 which is disposed between a pair of upright ears 78, the latter being secured to the upper surface of the locking bar 75. A pivot pin 79 extends through the boss 77 and the ears 78 to provide a pivotal connection of the boss 77 and the bolt 76 to the cover locking bar 75. The locking bars 74,7 5 are formed with

lateral slots

80,81 respectively, which are aligned with the bolts 76 so that the bolts 76 may be swung about their pivot pins 79 and through the

slots

80,81. A nut 82 is threaded on the bolt 76 and a washer 83, or the like, is secured to the end of the bolt 76 to form a retaining flange to prevent the nut 82 from being removed from the bolt 76.

Normally, the bolt 76 is disposed in depending position, as seen in FIG. 6, and. extends through the locking bars 74,75. The nut 82 is turned up on the bolt 76 against the underside of the locking bar 74, thereby locking the cover 55 in closed position. When it is desired to open the cover 55, a first step is to turn each of the nuts 82 down on the bolts 76 and to swing the bolts 76 upwardly about their respective pivot pins 79 to the position shown in phantom lines in FIG. 4. This releases the cover locking bar 76 from the lower locking bar 74 and permits the cover 55 to be raised as previously described.

Referring now to FIG. 5, there is a shaft 85 that extends through thereceptacle 45, with its axis coincident with the axis of the cylindrical shell 48. .The opposite ends of the shaft 85 are rotatably. supported on the

end walls

49,50. The means for rotatably supporting the opposite ends of the shaft 85 are the same, and accordingly, such supporting means will be described only with respect to the end of the shaft 85 at the feed or upstream end of the receptacle 45, it being understood that the description applies to the like supporting means at the discharge or downstream end of the receptacle 45 for the other end of the shaft 85.

The end wall 49 has a centrally disposed circular opening 86 which is considerably larger than the diameter of the shaft 85, and the shaft 85 extends through such opening 86. Within the opening 86, at the outer side of the end wall 49, there are placed the two halves of a disclike retainer 87, the latter having a central aperture through which the shaft 85 passes. The opening 86 is filled with a felt packing seal 88 that is placed adjacent to the disc 87. The felt seal 88 fills the opening 86 and forms a seal against the periphery of the shaft 85. The felt seal 88 is held in the opening 86, at the inside of the wall 49, by a pair of

rectangular retainer plates

89,90, as seen in FIG. 6. The

plates

89,90 are secured to the end wall 49 by a plurality of bolts 91. The rectangular plates 89,90.have semicircular cutouts, so that when placed side by side as shown, there is formed a circular opening through which the shaft 85 passes. Upon securing the

plates

89,90 to the end wall 49, the packing 88 is compressed in the end wall opening 86 between the retainer 87 and the

plates

89,90, whereby the packing 88 fills the opening 86 and seals the shaft 85 therein.

The shaft 85 projects beyond the end wall 49 and is formed with a reduced diameter end 92 that is received in a flange roller bearing 93 to be rotatably supported thereby. A ring 94 is disposed between the flange bearing 93 and the end wall 49. The ring 94 is secured to the end wall 49, as by welding. The internal diameter of the ring 94 is smaller than the diameter of the opening 86, whereby the ring 94 forms a shoulder to back the retainer 87 and to secure the latter in the opening 86. The flange roller bearing 93 is secured to the ring 94 and the end wall 49 by a plurality of bolts 95, or the like, as seen in FIG. 4. The ring 94 is partially cut away to provide an opening 96 at the bottom thereof, which is of substantial size. Any material which might get past the felt seal 88 will drop to the bottom of the ring 94 and out through the opening 96, and thereby such material is prevented from working its way into the flange roller bearing 93. A shaft guard 97 is secured to the end wall 49 below the ring 94 and extends upwardly therefrom to the exposed end of the reduced diameter shaft end 92. The shaft guard 97 has a cup 98 which covers the shaft end 92'. The shaft guard 97 is bolted to a channel support 99, which is secured to the end wall 49, as by welding. The shaft guard 97 is installed on that end of the continuous muller 20 that is the nondriven end.

The end wall 49 has a feed opening 100 disposed at one side of the shaft 85, and at the opposite side thereof there is a rectangular opening 101 for the supply or exhaust of a current of air that may flow through the muller receptacle 45 as previously described. The feed chute 27 terminates at its bottom in an opening that is aligned with and connects to the feed opening 100 for the discharge of sand into the muller receptacle 45. The air duct 40 connects to the rectangular opening 101 for the flow of air through the continuous muller, as above described.

The sand is received in the muller receptacle 45 at the feed or upstream end and then flows in a downstream direction through the receptacle 45 to the downstream or discharge end thereof, at which there is a discharge section 102 from which the sand discharges through the discharge chute 38. As the sand flows through the receptacle 45, it is successively mulled by a plurality of successive mulling

assemblies

105a, 105b, 105 c, 105d, 105e, l05f, 105g, 105k, all of which are identical, except for the mulling assembly 1050 which has an additional element, as will be described hereinafter. In the interest of clarity, FIG. 5 includes a complete illustration of only the mulling

assemblies

105a, 105b, which are the first and second mulling assemblies in the direction of flow from upstream to downstream. The remaining mullingassemblies 105c-h are merely represented by an outline of the mulling wheels and plows thereof. The description of the mulling assemblies 105a, 105k is applicable to the mulling assemblies 105ch, except as to the one added element of the mulling assembly 105a, as will be specifically mentioned hereinafter.

The several mulling assemblies 105ah are secured to the shaft to be moved thereby about the axis of the shaft 85. The mulling assemblies l05ah are disposed at equally spaced positions along the shaft 85 between the feed or upstream end of the mulling receptacle 45 and the discharge section 102. Thus, as the sand flows through the muller receptacle 45 from the feed or upstream end thereof towards the discharge section 102 at the discharge or downstream end of the muller receptacle 45, the mulling assemblies 105a-h successively operate on and mull the sand. The successive positions ofthe several mulling assemblies l05a-h along the shaft 85 are apparent in FIG. 5, and are further indicated by the letters a-h at the bottom of FIG. 5, identifying and locating the several successive mulling positions along the length of the mulling receptacle 45.

For each mulling assembly 105a-h there is secured to the shaft 85 a partial hub 106, as best seen in FIGS. 5 to 8. The hub 106, as illustrated herein, extends through an angle somewhat greater than 180, sufficient to receive three bolts at positions spaced relatively to each other. Each partial hub 106 is firmly secured to the shaft 85, as by welding, for

mounting a mulling assembly 105.

Referring to FIG. 7, there is illustrated therein the mulling assembly b, which is typical of the construction of the several mulling assemblies l05ah. The mulling assembly 105b is constructed on a frame 107. The frame 107 comprises a center hub portion 108 formed with an arcuate recess 109 that is open along a diametral line, whereby the frame 107 and the mulling assembly 105b may be placed over the shaft 85. The recess 109 is formed on a circular are having a radius equal to the radius of the shaft 85. Thus, the frame 107 may be seated on the shaft 85. The hub portion 108 of the frame I07, and the partial hub 106, are each formed with three apertures which may be at 90 spaced positions relative to each other about the axis of the shaft 85. The apertures in the partial hub 106 and in the center hub portion 108 of the frame 107 are aligned with each other to receive three bolts 110, by which the frame 107 is securedlo the partial hub I06 and is mounted on the shaft 85. In effect then, the entire 'mulling assembly 105b is secured to the shaft 85 by the several bolts 110. By releasing the bolts 110, the entire mulling assembly 105b may be removed from the shaft 85 for replacement, repair or other maintenance of the same as may be required.

The frame 107 further includes a first mounting arm 111 and a second mounting arm 112. The mounting arms 111,112 are formed as extensions of the frame hub portion 108, and extend from opposite sides of the hub portion 108. The outer end of the first mounting arm 111 is formed with an integral sleeve 113. Within the sleeve 113 there are provided a pair of torsion bushings 114, which are press fitted in the bore of the sleeve 113, as seen in FIG. 9. Each torsion bushing 114 comprises a metal sleeve 115, on the outer surface of which there is bonded a cylinder 116 of rubber, or like yieldable material. The bond between the metal sleeve 115 and the outer rubber cylinder 116 causes the latter to be immovable relatively to the metal sleeve 115 at the metal-rubber junction. However, the rubber cylinder 116 is yieldable to an increasing extent as the radial distance of the rubber cylinder 116 increases from the junction of the rubber to the metal. It is this yieldable characteristic of the torsion bushing 114 that is utilized in the mulling assembly 10511.

The two torsion bushings 114 are press fitted in the bore of the sleeve 113, whereby the rubber cylinders 116 are compressed, setting up a force pressing the rubber against the bore of the sleeve 113, as well as against the metal sleeve 115 of the torsion bushing 114. Such pressure, in effect, immovably secures the peripheral surfaces of the rubber cylinders 116 to the bore of the sleeve 113. Then, if there is a torsional force applied to the metal sleeve 115, such force is resisted by the rubber cylinders 116 which tend to maintain themselves in a neutral position in which they are not distorted. If the torsional force exceeds the spring rate of the rubber cylinders 116, then there is relative rotation of the metal sleeves 115 and the sleeve 113.

A hub 117 is formed with an integral shaft 118 that is received in the bores of the torsion bushings 114, and has a threaded end that projects beyond the torsion bushings 114. The hub 117 bears against an end metal sleeve 115 of the torsion bushings 114 that projects beyond the sleeve 113, whereby the hub 117 is spaced from the one end of the sleeve 113. A washer 119 is mounted on the projecting end of the shaft 118 and bears against an end ofa metal sleeve 115 of the torsion bushings 114 that projects beyond the other end of the sleeve 113, to space the washer 119 from the other end of the sleeve 113. A nut 120 is turned on the threaded end of the shaft 118, whereby the hub 117 is pressed against one end ofa metal sleeve 115 of the torsion bushings 114, and the washer 119 is pressed against another end ofa metal sleeve 115 of the torsion bushings 114. In effect then, the hub 117 is fixedly secured to the metal sleeve 115 of the torsion bushings 114. There is nocontact between the hub 117 and the rubber cylinders 116 of the torsion bushings 114 by reason of the conical configuration of each end of the rubber cylinders 116.

The torsion bushings 114 are interposed between the mounting hub 117 and the sleeve 113 of the frame 107. Thus, the hub 117 can rotate or pivot about the axis of its shaft 118 and relatively to the sleeve 113. However, the interposition of the torsion bushings 114 provides a yieldable means which resists such rotation or pivotal movement of the hub 117, to the extent of the spring rate of the rubber cylinders 116 of the torsion bushings 114.

A centrally disposed boss 121 projects from the outer side of the hub 117. A supporting lever 122 is formed with an aperture 123 in which the boss 121 is received when the supporting lever 122 is mounted on the hub 117. The supporting lever 122 is fixedly secured to the hub 117 by a plurality of bolts 124, of which there may be three.

The supporting lever 122 has the form of a crank and comprises an outer arm 125 and an inner arm 126. At the end of the outer arm 125 there is formed an integral axle 127, the axis of which is parallel to the axis of the shaft 85. A first bearing 128 is mounted at the inner end of the axle 127 abutting an annular shoulder 129. A second bearing 130 is mounted on the axle 127 at the outer end thereof, with a spacer 131 disposed between the

bearings

128, 130 to maintain them in spaced-apart positions. The axle 127 has a threaded end 132 on which there is turned a nut 133 which secures the

bearings

128, 130 on the axle 127.

A mulling wheel 135 is rotatably mounted on the axle 127, with the bearings 128,130 interposed between the mulling wheel hub 136 and the axle 127. The bore 137 of the mulling wheel hub 136 is formed with a shoulder 138 at the inner end thereof against which the bearing 128 is seated. in the outer end of the bore 137 there is placed a spacer 139 which abuts the second bearing 130. The axle 127 terminates short of the end of the bore 137. A cover 140 overlies the outer end of the bore 137 and is secured to the hub 136 by a plurality of bolts 141. An O-ring 142 is interposed between the cover 140 and the hub 136 to assure a seal therebetween. The cover 140 thus closes the outer end of the bore 137 and prevents material from getting into the bore 137 and contaminating the bearings 128,130. The cover 140 also secures the spacer 139 in position against the second bearing 130 and thereby fixes the position of the mulling wheel 135 on the axle 127.

It is necessary that the inner end of the bore 137 also be sealed to prevent material from reaching the bearings 128,130 and contaminating these. Accordingly, at the inner end of the bore 137 there is formed an outwardly facing annular seat 143. The outer arm 125 is also formed with an annular seat 144 which is aligned with and oppositely disposed with respect to the first annular seat 143. Between the annular seats 143,144 there is placed a rotating seal 145. Such rotating seal 145 comprises a pair of like, oppositely disposed metal rings 146,147 that have abutting surfaces. The abutting surfaces of the metal rings 146,147 have a superfine finish, such that the rings 146,147 are rotatable relatively to each other, but by abutment of their superfine finished surfaces there is maintained such an intimate contact of the rings 146,147 with each other that there is effected a seal between the relatively rotating rings 146,147. An elastic ring 148 is disposed between the first annular seat 143 and the metal ring 146, and a similar, oppositely disposed elastic ring 149 is disposed between the other annular seat 144 and the metal ring 147. The elastic rings 148,149 are press fitted in the respective annular seats 143,144 and extend therefrom in opposite directions at an angle towards the opposite annular seats on the respective rings 146,147. The angular disposition of the elastic rings 148,149 is such as to press the metal rings 146,147 towards each other to maintain the surfaces thereof in abutting contact. Also, the elastic ring 148 maintains the metal ring 146 rotatively fixed relatively to the hub 136, and the elastic ring 149 similarly maintains the metal ring 147 rotatively fixed relatively to the outer arm 126, whereby rotation of the mulling wheel 135 produces relative rotation of the metal rings 146,147 while sealing engagement thereof is maintained by the elastic rings 148,149. The elastic rings 148,149 seal the area between the metal rings 146,147 and the annular seats 143,144, respectively.

The mulling wheel 135 has a tire 153 formed of rubber, or like yieldable material. The tire 153 is bonded to a metal band 154, and the tire 153 is secured to the hub 136 by press fitting the metal band 154 on the hub 136. Thus, the mulling wheel 135 is freely rotatable on the axle 127 by the bearings 128,130, which are interposed between the hub 136 and the axle 76 the bore 137 of the hub 136 is sealed at its outer end by the cover 140, and at its inner end by the rotating seal 145, the latter effecting a seal between the inner end of the bore 137 and the outer arm 125. Thus, the bearings 128,130 are protected from the material that is dispersed in the receptacle 45. Were such materials to reach the bearings 128,130, the latter could be damaged and rendered ineffective in short order. The seals also serve to retain the lubricant for the bearings 128,130 within the bore 137.

The outer arm 125 supports a dam 155, the latter being a planar, plate member that is laterally disposed with respect to the axis ofthe shaft 85. The boss 121 has a centrally disposed pin 156 projecting therefrom, and the dam has an aperture 157 of the same size as the pin 156, to receive the latter. The dam 155 includes a first arcuate slot 158 and a second arcuate slot 159, through which there extend bolts 160,161, respectively, that are threaded into the outer arm 125 to secure the dam 155 on and against the outer arm 125. The

slots 158,159 are spaced at different distances from the axis of the pin 156. Thus, there are three points of support for the dam 155, these being the pin 156 and the two bolts 160,161. The slots 158,159 are formed on arcs of concentric circles that have their center on the axis of the pin 156. Thus, the position of the dam 155 can be adjusted about the axis of the pin 156. The outer edge 162 of the dam 155 is formed on a circular are having its center on the axis of the shaft 85. Thus, the outer edge 162 is concentric with the cylindrical wall of the receptacle 45. By adjustment of the position of the dam 155, the spacing between its outer edge 162 and the wall of the cylindrical receptacle 45 may be adjusted for a purpose that will be more fully explained hereinafter.

The inner arm 126 extends from the boss 123 to a position adjacent the shaft 85. At the end of the inner arm 126 there is secured an eccentric disc 163 which abuts the shaft 85. A bolt 164 releasably secures the eccentric disc 163 to the inner arm 126, whereby the position of the eccentric disc 163 may be adjusted, thereby varying the spacing between the end of the inner arm 126 and the shaft 85, when the eccentric disc 163 is in contact with the shaft 85. The disposition of the outer arm 125 is adjusted accordingly, with the ultimate effect of adjusting the outermost position of the mulling wheel 135 relatively to the wall of the cylindrical receptacle 45.

The second mounting arm 112 of the mulling assembly frame 107 has three pairs of apertures 165,166, 167 which are spaced from each other and are disposed in two circular arcs that are concentric. A plow 170 is mounted on the second mounting arm 112. The plow 178 has an arm 171 with a bifurcated end 172 that has a pair of apertures which are spaced apart the same distance as the individual apertures of each pair of apertures 165,166,167. The second mounting arm 112 is received within the bifurcated end 172 of the plow arm 171 and is releasably secured thereto by a pair of bolts 173 extending through the apertures in the bifurcated end 172 of the plow arm 171 and one pair of the apertures 165,166,167, which is aligned therewith. The plow arm 171 extends towards the cylindrical shell 48 of the receptacle 45 and terminates in an integral foot 174 that extends laterally to opposite sides of the arm 171. The foot 174 has a flat surface facing inwardly of the receptacle shell 48, and this flat surface is inclined with respect to a tangent to the receptacle shell 48, and is substantially parallel to the axis of the shaft85. A plow blade 175 is releasably secured to the foot 174. The plow blade 175 includes a pair of bolts 176 disposed one on each side of the arm 171 and extending through aligned apertures in the foot 174 to receive nuts that are turned on the bolts 176 to firmly secure the plow blade 175 to the foot 174. The leading edge of the plow blade 175 is disposed closely adjacent to the inner surface of the receptacle shell 48 and extends therefrom at the same angle of inclination as the foot 174.

The inclination of the plow blade 175 may be adjusted by selection of the pair of apertures 165,166,167 to which the plow 178 is secured by means of the bolts 173. The pairs of apertures 165,166,167 are disposed in concentric circular arcs having a center approximately on the leading edge of the plow blade 175, whereby in any position of adjustment of inclination of the plow blade 175 the spacing between the leading edge of the plow blade 175 and the inner surface of the receptacle shell 48 remains substantially the same.

The inner cylindrical surface of the receptacle 45 provides the mulling surface on which the sand is mulled as it flows through the receptacle in a longitudinal direction. In order to form a suitable mulling surface on the receptacle shell 48, there is provided a liner 188 formed of rubber, or like yieldable material. The liner 188 is formed in three sections, of which two liner sections 181,182 are of equal arcuate length and are secured to the receptacle shell 48, and the third liner section 183 is of shorter arcuate length and is secured to the cover 55 Except for the arcuate length of the several sections 181,182,183 of the liner 180, the construction of these is the same, and accordingly, only one liner section need be described in detail.

The liner section 181 comprises a metal backing plate 184 which extends the length of the receptacle 45 from one end wall 49 to the other end wall 50. Bonded to the metal plate 184 is a sheet 185 of rubber, or like yieldable material, which is the element of the liner 180 that actually forms the mulling surface inside the receptacle 45. The metal backing plate 184 of the liner section 181 is the element by which the liner section 181 is secured to the receptacle shell 48. For this purpose, the rubber sheet 185 is set back from each end of the metal backing plate 184 to expose the latter along a narrow strip. Curved metal bars 186,187 are placed against the metal backing plate 184 at the end walls 49,511, respectively, for the purpose of securing the liner 180 to the receptacle shell 48. Each of the curved bars 186,187 is of the same arcuate length and the same thickness as the rubber sheet 185, so that the curved bars 186,187 are coextensive and flush therewith. Each curved bar 186,187 has several flush bolts 188 which extend through the curved bars 186,187, the metal backing plate 184 and the receptacle shell 48, and project beyond the latter for the reception of suitable nuts by which the curved bars 186,187, are firmly secured to the receptacle shell 48 and thereby secure the liner section 181 in place as described.

As best seen in FIG. 6, each of the liner sections 181,182 extends through one-half the arcuate length of the receptacle shell 48, not including the arcuate length of the cover 55. The liner sections 181,182 abut each other to form the liner 180 extending continuously around the fixed portion of the receptacle shell 48. The liner section 183 is coextensive with the arcuate extent of the cover 55, and when the latter is in closed position, the ends of the liner section 183 abut the exposed ends of the liner sections 181,182, whereby the liner 188 extends through the full inner circumference of the receptacle shell 48, and the rubber sheet 185 thereof provides an endless mulling surface that faces inwardly of the receptacleshell 48 and is disposed around the axis of the shaft 85. As seen in FIG. 5, the liner section 181 is cut away at the discharge section 102 to provide an opening connecting to the discharge chute 38.

Each mulling assembly a-h is operative to mull the sand in the receptacle 45. The mulling, as such, is accomplished by the several mulling wheels of the mulling assemblies 105ah and the liner 180. The mulling action, comprising the pressing, kneading and mixing of the sand, takes place between the mulling wheels 135 and the liner 180. The sand is dispersed on the liner about the axis of the shaft 85, and the mulling wheels 135 engage the sand that is so dispersed on the liner 180, and there is a pressing, kneading and mixing action of the mulling wheels 135 on the sand to accomplish the mulling of the sand. The sand as it flows longitudinally through the receptacle 45, and is dispersed therein, is highly abrasive in its action, on the elements of the apparatus, and particularly so in respect to the elements which are operative to work the sand. Thus, each mulling wheel 135 is provided with the tire 153 made of yieldable material, and likewise, the liner 180 includes the sheet of yieldable material to form the mulling surface, which are more resistant to the wearing, abrasive action of the sand than would be the case with nonyieldable materials, for example, metal. The operation of the continuous muller 20 will be described in greater detail hereinafter.

The construction of the mulling assembly 1115b is typical of each of the mulling assemblies l05ah, each of which includes all the elements which have been described. The mulling assembly 105a includes an additional element which is the intake accelerating plow 190, as best seen in FIGS. 6 and 10. A bar 191 is secured to the first mounting arm 111 of the frame 107 in a suitable manner, as by welding. The plow has an arm 192 extending upwardly to meet the lower end of the bar 191 and is releasably secured to the latter by a pair of bolts 193. The bolts 193 may be released for the purpose of replacing the intake accelerating plow 190 if it should experience excessive wear. The plow 190 has a plow blade 194 which is disposed substantially parallel to the axis of the shaft I ll 85, and is in front of the mulling wheel 135 to lead the latter in the direction of movement thereof around the axis of the shaft 85, this being in a clockwise direction, as viewed in FIG. 6. The intake accelerating plow 190 meets the sand as it initially flows into the receptacle 45, and gives such sand an initial acceleration or movement, and in effect disperses the sand to prevent it from piling up excessively in front of the mulling wheel 135 of the first mulling assembly 105a. By reason of the gap between the plow blade 194 and the liner 180, a substantial amount of sand remains ahead of the mulling wheel 135 to be acted upon thereby. Other than as stated with respect to the mulling assembly 105a, the several mulling assemblies 105ah are alike in construction.

At the discharge section 102 of the receptacle 45 there is provided a radially extending sweeper blade 195, as best 27 seen in FIGS. and 11. Near the end wall 50, a partial hub 196 is secured to the shaft 85, as by welding. The partial hub 196 has the same configuration as the several partial hubs 106 for the mulling assemblies 105a-h. The sweeper blade 195 has a hub portion 197 that is placed on the shaft 85 adjacent the partial hub 196, and the sweeper blade 195 is secured to the partial hub 196 by a plurality of bolts 198, which may be three in number. The sweeper blade 195 is formed as a planar element disposed in a plane that is placed laterally with respect to the shaft 85. The sweeper blade 195 rotates with the shaft 85 in front of the end wall 50. As the sand flows downstream and reaches the discharge section 102 it would normally have a tendency to adhere to the end wall 50 and to accumulate on the same. However, the rotating sweeper blade 195 prevents such accumulation of the sand, and accordingly, the sand continuously discharges through the discharge chute 38 at the same rate as the rate of movement of the sand into and through the receptacle 45.

The operation of the mulling apparatus 20 will now be described. The sand flows into the receptacle 45 from the feed chute 27 and through the feed opening 100 at the feed or upstream end thereof. As the sand enters the receptacle 45, it is met by the intake accelerating plow 190 which starts the sand in movement around the axis of the shaft 85 and prevents an excessive accumulation of sand in front of the mulling wheel 135 of the mulling assembly 105a. The intake accelerating plow 190 impels the sand in a lateral direction with respect to the axis of the shaft 85. However, the sand also has a tendency to fan out upstream and downstream from the opposite side edges of the plow 190. On the upstream side the sand is blocked by the end wall 49, and on the downstream side the sand is blocked by the dam 155. Accordingly, the movement of the sand impelled by the accelerating plow 190 is essentially in a lateral direction with no significant upstream or downstream movement.

The mulling wheel 135 of the mulling assembly 105a follows closely behind the intake accelerating plow 190, the mulling assembly 105a being moved in a clockwise direction by the shaft 85 about the axis of the latter, as viewed in FIG. 6. The dam 155 extends to almost the axis of the mulling wheel 135. Behind the dam 155 and ahead of the mulling wheel 135 there is retained sand that is engaged by the mulling wheel 135. Thus, the association of the intake accelerating plow 190 with the dam 155 and the end wall 49 assures that while excessive accumulations of sand are removed from the path of the mulling wheel 135, nevertheless a substantial amount of sand remains in the path of the mulling wheel 135 to be engaged by the latter and to be pressed, kneaded and mixed thereby on the mulling surface of the liner 180.

The shaft 85 is rotated at a relatively high rate of speed, sufficient to cause the mulling wheel 135 to be moved outwardly towards the mulling surface of the liner 180 by centrifugal force. The limit of the outward movement of the mulling wheel 135 in response to the action of centrifugal force is determined by the upper arm 126 and the setting of the eccentric disc 163. The mulling action is found to be most effective when there is provided a gap between the periphery of the mulling wheel 135 and the mulling surface of the liner 180, for

example as seen in FIGS. 6'and 7. The maintenance of such a gap prevents the grains of sand from being crushed, which would otherwise occur, and the action of the mulling wheel 135 on the sand is then, in true effect, only a pressing, kneading and mixing action, which is the requisite action for properly combining-the sand with the bonding ingredients. The optimum gap between the periphery of the mulling wheel 135 and the mulling surface of the liner 180 may be different for different sands, different combinations of sand and bonding ingredients, and different operating conditions. Accordingly, the eccentric disc 163 may be set to provide the appropriate gap between the mulling wheel 135 and the mulling surface of the liner 180. The eccentric disc 163 also provides an adjustment for wear of the mulling wheel tire 153. As such tire 153 wears down, the gap increases and by resetting the eccentric disc 163 the gap may be closed and restored to its proper dimension.

As the mulling wheel 135 moves around the axis of the shaft and over the mulling surface of the liner 180 to press, knead and mix the sand, it also packs the sand against the mulling surface. Such packed sand is removed from the mulling surface of the liner 180 by the plow 170 that follows behind the mulling wheel 135 in the direction of movement of the mulling assembly a around the axis of the shaft 85. The plow blade 175 has its leading edge disposed closely adjacent to the mulling surface of the liner 180, with sufficient clearance being provided to prevent the plow blade 175 from damaging the liner 180. The plow blade 175 engages the sand that is packed on the mulling surface, to remove such sand therefrom by a scraping action. By reason of the speed of the plow 170 over the mulling surface of the liner 180, and the selected angle of the plow blade 175 with a tangent to the mulling surface, the engagement of the plow blade 175 with the sand causes the latter to be impelled in a lateral direction with respect to the axis of the shaft 85, and about the axis of the shaft 85 over the mulling surface, whereby such sand is broken up and is dispersed in the receptacle 45. The sand fans out in an upstream and a downstream direction from the plow blade 175, as an incident to being impelled in a lateral direction. In order not to impede or interfere with the impulsion and dispersion of the sand by the plow blade 175, the plow 170 is spaced a sufficient distance behind the mulling wheel such that the sand effectively clears the mulling wheel 135 as it is impelled and dispersed by the plow 170.

It is a concomitant of the impelling action of the plow on the sand that the sand is distributed around the circumference of the receptacle 45 and is substantially uniformly distributed over the mulling surface of the liner 180 throughout the circumference of the latter. Thus, the sand is mulled on the mulling surface of the liner 180 between it and the mulling wheels 135 throughout the circumference of the cylindrical mulling surface.

As the sand is impelled laterally, it fans out from the plow blade in upstream and downstream directions. However, the sand which fans out from the plow blade 175 in an upstream direction meets greater resistance to such movement than does the sand which fans out in a downstream direction, by reason of the fact that additional sand is continuously being delivered at the upstream end of the receptacle 45, while sand is continuously discharging from the discharge section 102 at the downstream end of the receptacle 45. Thus, there is a pressure head condition in the receptacle 45, whereby the sand flows in a stream through the receptacle 45 in a longitudinal direction from the feed or upstream end to the discharge or downstream end thereof, rather than being positively fed through the receptacle 45. In this manner, a given portion of sand flows longitudinally to the successive mulling positions ah along the length ofthe muller receptacle 45, to be successively mulled by the respective mulling assemblies 105a-h. The plows 170 do not act in any manner to positively feed the sand in a longitudinal direction as do plows that are sharply angled or inclined with respect to the longitudinal axis. The plows 170 are operative to put the sand in motion and to each mulling assembly 105 trails, or is disposed behind the preceding mulling assembly 105 in the direction of rotation thereof about the axis of the shaft 85. In the preferred embodiment of the invention disclosed herein, the angle between one mulling assembly 105 and a successive mulling assembly 105 is less than 180, so that when viewed along the shaft 85 the successive mulling assemblies 105ah have the appearance of being disposed along a helix.

The relative angular disposition of one mulling assembly with respect to the preceding mulling assembly is best illustrated in FIG. 6, wherein the mulling assembly 105a is illustrated in solid lines, and certain elements of mulling assembly l05b are illustrated in phantom lines; the latter are identified as the mulling wheel 135b, the dam 155b and the plow 170b. The plow blade 175 of the mulling assembly 105a is disposed somewhat in alignment in a longitudinal direction with the leading edge of the dam l55b. The mulling wheel 135b follows behind the dam 155b, although it overlaps the dam 155b, and the plow 17% is spaced a distance behind the mulling wheel 135 to follow the latter. As the plow blade 175 of the mulling assembly 105a scrapes the sand from the mulling surface and disperses the sand about the axis of the shaft 85, the sand flows downstream. However, the dam l55b of the successive mulling assembly 105b, to some extent, overlaps the plow blade 175, and although spaced downstream therefrom, in effect, it follows the plow blade 175. Thus, as the sand flows downstream by reason of being put in motion and dispersed over the mulling surface about the axis of the shaft 85, the

dam 'l55b is interposed in the line of flow of the sand to momentarily interrupt such flow, whereby the dam 1551; causes a mass of sand to accumulate in front of the mulling wheel 13512. As the mulling wheel 135b follows the darn 155b in the clockwise movement thereof, it works its way through the mass of sand that is momentarily accumulated behind the dam 155b and in front of the mulling wheel 135b. Thus, in effect, the dam 155b functions to collect .the sand to be worked by the mulling wheel 135b. The working or mulling of the'sand is enhanced by the fact that there is the accumulation of sand behind the dam 155b, in that there is an augmented movement of the sand particles relatively to each other, which improves the pressing, kneading and mixing action on the sand by which it is combined with the bonding ingredients, and to coat the sand particles with such bonding ingredients.

- -As the mulling wheel 135 moves around the axis of the shaft 85, each mulling wheel 135 also rotates about its own axis. The mulling wheels 135 do not rotate on the mulling surface of the receptacle liner 180. Rather, the mulling wheels 135 engage the sand on the mulling surface of the liner 100 and rotate relatively to the mulling surface. At all times, the mulling wheels 135 are thrust outwardly by the centrifugal force acting on the same, so that the mulling wheels 135 effectively press the sand between the peripheries of the mulling Wheels 135 and the mulling surface of the receptacle liner 180; As the mulling wheels 135 thus work their way through the'sand that is dispersed on the mulling surface, all the while rotating about their own axes, the mulling wheels 135 are effectively pressing, kneading and mixing the particles of the sand, whereby there is ultimately produced a complete homogeneous combination of the sand with the bonding ingredients, in which the individual grains of the sand are coated with the bonding ingredients.

There is a gap between the arcuate outer edge 162 of the dam 155 and the mulling surface of the liner 180. This gap can be adjusted by means of the slots 158,159 and the bolts 160,161. An increased gap will have the "effect of permitting more sand to flow downstream throughthe gap and past the clam, while narrowing the gap has the opposite effect. The ulti' mate effect of such adjustment is to adjust the retention time of the sand in the receptacle45, which in turn affects the quality of the mulling action. Adjustment of the position of the dam 155 is also required in ordei' that it-rr ay be properly positioned in accordance with the selective positioning of the mulling wheel relatively to themullirig' surface, by means of the eccentric disc 163, as previously described.

The plow 170b follows at a distance behind the mulling wheel 135k and it scrapes the mulled sand from the mulling surface and disperses the sand over the mulling surface and about the axis of the shaft 85, as has been described. The operation, as described with respect to the mulling

assemblies

105a, 105b, repeats itself downstream as to the successive mulling assemblies 105ah. The total effect of the operation is that the sand continuously flows through the muller receptacle 45 towards the discharge section 102; however, such flow is momentarily interrupted as the respective dams move about the axis of the shaft 85. Such interruptions of the downstream flow of the sand merely restrain the continuous flow of a portion of the sand in order to enhance the mulling of the same. The effect of the operation of the dams 155 is to reduce the effective or overall rate of flow of the stream of sand through the receptacle 45, so that the retention time of the sand in the receptacle 45 is sufficient for effective mulling of the sand, as well as to produce an accumulation of sand in front of the mulling wheels 135 for effective mulling action.

It is believed that during the operation of' the mulling apparatus 20 the sand is distributed on the mulling surface of the liner 180 in a cylinder from the upstream end to the discharge section 102 at the downstream end of the receptacle 45. It appears that such cylinder diverges internally towards the discharge section 102, so that, in effect, there is a downhill condition in the receptacle- 45. Since the sand is always maintained in a dynamic condition of movement in the receptacle 45 by the action of the plows dispersing the sand over the mulling surface, the sand readily flows downstream under the force of the pressure head that exists by reason of the sand being continuously fed in at the upstream end of the receptacle 45 and discharged at the discharge section 102.

The torsion bushings 114 provide a flexible or yieldable connection between the shaft 118 and the sleeve 113. The rubber cylinders 116 of the torsion bushings 114 have a neutral position and any distortion thereof from the neutral position gives rise to force which opposes such distortion. This force may be characterized as the spring rate of the yieldable cylinders 116. The interposition of the torsion bushings 114 between the sleeve 113 and the shaft 113 produces a smoother operation of the mulling wheels 135 under the action of centrifugal force, in that the wheels 135 are not subjected to sudden and erratic thrusting thereof in response to the action of centrifugal force, or upon encountering uneven accumulations of sand on the mulling surface.

It has been found desirable to place the torsion bushings with the neutral position of the yieldable cylinders 116 located in such position, that the mulling wheels 135 in the idleposition of the apparatus are placed at a position intermediate the periphery of the shaft 85 and the mulling surface of the liner 180. When the apparatus is in operation, the relatively high speed of rotation of the shaft 85 gives rise to a centrifugal force that thrusts the mulling wheels 135 to their maximum outer position, as determined by the selected position of the eccentric disc 163. In moving to such position, the yieldable cylinders 116 of the torsion bushings 1 14 are distorted by reason of the metal sleeves 115 turning relatively to the fixed sleeves 113 on the first mounting arms 111. The distortion of the torsion bushings 114 is greatest at the maximum outer position of the mulling wheels 135, and accordingly, the resisting force of the torsion bushings is greatest at this position of the mulling wheels 135. The resisting force of the torsion bushings 114 acts in the opposite direction from the centrifugal force on the mulling wheels 135, and the effect is to reduce the centrifugal force. However, if for any reason the mulling wheels 135 move inwardly, then the resisting force of the torsion bushings 114 is reduced, and the negative effect thereof on the centrifugal force is likewise reduced. The overall effect is a degree of compensation by the torsion bushings 114 for the loss of centrifugal force that occurs by reason of the mulling wheels 135 moving inwardly from their outermost positions. The torsion bushings 114 may be selected to provide such magnitude of resisting force and cushioning effect as may be desired for a given construction of the continuous muller 20.

The mulling apparatus 20 which is described herein provides a means for practicing a novel method of mulling material, such as sand. In such method, the sand is continuously delivered to and discharged from the receptacle within which the mulling is performed. The sand is dispersed in the receptacle and is distributed on a cylindrical mulling surface, whereby the sand continuously flows in a stream through the receptacle. The sand that is distributed on the mulling surface is mulled on such mulling surface. The mulling takes place concurrently with the flow of the stream of sand through the receptacle. The total effect of the several steps is a process for continuously mulling sand such that sand may be continuously delivered and fed into the receptacle to be mulled, and likewise, the sand is continuously discharged from the receptacle after such mulling operation.

The improved continuous mulling apparatus described herein provides a means whereby the material flows continuously in a stream through the apparatus. Such flow is interrupted or restrained from time to time for accumulating a quantity of material to be mulled. However, there is no disturbance of the overall continuous flowing condition of the material from the upstream end of the apparatus to the downstream end of the apparatus. In accordance with the invention, the material is dispersed about the axis of the mulling apparatus in a lateral direction to distribute the material on the mulling surface, and is maintained in a dynamic condition for the downstream flow of the material through the apparatus, which is required for continuous operation. It is an inherent feature of the mulling operation disclosed herein that the material is very effectively aerated by reason of its dispersion in the apparatus, which causes the material to be broken up so that when ultimately discharged it is in true granular fonn.

Obviously those skilled in the art may make various changes in the details and arrangement of parts without departing from the spirit and scope of the invention as defined by the claims hereto appended, and applicant therefore wishes not to be restricted to the precise construction herein disclosed.

lclaim:

l. The method of continuously mulling material comprising the steps, continuously feeding material into a substantially level receptacle having an inwardly facing cylindrical mulling surface disposed around a laterally extending axis, dispersing the material around the axis and distributing the material annularly over the cylindrical mulling surface to produce a continuously flowing condition of the material in a longitudinal direction through the receptacle, pressing, kneading and mixing the material on the cylindrical mulling surface to mix and combine the material with added ingredients, and continuously discharging mulled material from the receptacle.

2. The method of continuously mulling material comprising the steps, continuously feeding material and added ingredients into a substantially level receptacle having an inwardly facing cylindrical mulling surface disposed around a laterally extending axis, dispersing the material and added ingredients around the axis and distributing the material and added ingredients annularly over the cylindrical mulling surface to produce a continuously flowing condition of the material and added ingredients in a longitudinal direction through the receptacle,

pressing, kneading and mixing the material and added ingredients on the cylindrical mulling surface to mix and combine the material with the added ingredients, and continuously discharging mulled material from the receptacle.

3. The method of continuously mulling material comprising the steps, continuously feeding material into a substantially level receptacle having a inwardly facing cylindrical mulling surface disposed around a laterally extending axis, impelling the material in a direction laterally of the axis to disperse the material around the axis and to distribute the material annularly over the cylindrical mulling surface to produce a continuously flowing condition of the material in a longitudinal direction through the receptacle, pressing, kneading and mixing the material on the cylindrical mulling surface and continuously discharging mulled material from the receptacle.

4. The method of continuously mulling material comprising the steps, continuously feeding material into a substantially level receptacle having an inwardly facing cylindrical mulling surface disposed around a laterally extending axis, dispersing the material around the axis and distributing the material annularly over the cylindrical mulling surface to produce a continuously flowing condition of the material in a longitudinal direction through the receptacle, pressing, kneading and mixing the material on the cylindrical mulling surface, said step of dispersing and distributing the material following the step of pressing, kneading and mixing the material thereby to scrape compacted material from the mulling surface, and continuously discharging mulled material from the receptacle.

5. The method of continuously mulling material comprising the steps, continuously feeding material into a substantially level receptacle having an inwardly facing cylindrical mulling surface disposed around a laterally extending axis, dispersing the material around the axis of the cylindrical mulling surface and distributing the material annularly over the cylindrical vmulling surface to produce a continuously flowing condition of the material in a longitudinal direction through the receptacle, pressing, kneading and mixing the material on the cylindrical mulling surface, successive steps of pressing, kneading and mixing the material is aforesaid, successive steps of dispersing and distributing the material as aforesaid, and continuously discharging mulled material from the receptacle.

Claims

1. The method of continuously mulling material comprising the steps, continuously feeding material into a substantially level receptacle having an inwardly facing cylindrical mulling surface disposed around a laterally extending axis, dispersing the material around the axis and distributing the material annularly over the cylindrical mulling surface to produce a continuously flowing condition of the material in a longitudinal direction through the receptacle, pressing, kneading and mixing the material on the cylindrical mulling surface to mix and combine the material with added ingredients, and continuously discharging mulled material from the receptacle.

2. The method of continuously mulling material comprising the steps, continuously feeding material and added ingredients into a substantially level receptacle having an inwardly facing cylindrical mulling surface disposed around a laterally extending axis, dispersing the material and added ingredients around the axis and distributing the material and added ingredients annularly over the cylindrical mulling surface to produce a continuously flowing condition of the material and added ingredients in a longitudinal direction through the receptacle, pressing, kneading and mixing the material and added ingredients on the cylindrical mulling surface to mix and combine the material with the added ingredients, and continuously discharging mulled material from the receptacle.

5. The method of continuously mulling material comprising the steps, continuously feeding material into a substantially level receptacle having an inwardly facing cylindrical mulling surface disposed around a laterally extending axis, dispersing the material around the axis of the cylindrical mulling surface and distributing the material annularly over the cylindrical mulling surface to produce a continuously flowing condition of the material in a longitudinal direction through the receptacle, pressing, kneading and mixing the material on the cylindrical mulling surface, successive steps of pressing, kneading and mixing the material is aforesaid, successive steps of dispersing and distributing the material as aforesaid, and continuously discharging mulled material from the receptacle.