IMPROVED CONTINUOUS CENTRIFUGAL MACHINE

Abstract: A continuous centrifugal machine of the conical basket type, useful in sugar manufacture for separating crystals from syrup, comprises a conical basket (12) having its shaft (14) driven from a motor (44) via a belt (88) and a pulley (82) that is held in a fixed position on a support shaft (78) and carries a stub shaft (84) connected with the basket shaft (14) by a flexible coupling (86) to enable gyratory motion of the basket assembly against the resistance of buffering assemblies (40). The position of the support shaft (78) is adjustable for alignement of the shafts (14, 84) by an adjustable mounting arrangement (52, 53, 56, 58, 64) which also keeps the pulley (82) constantly aligned with the belt (88) so that the belt will not be subject to variations of moment loads. An annular chambering unit (160) disposed around and beneath the basket (12) is seated on a support ring (36) of the base structure (32, 34, 36). The chambering unit includes a base wall (62), upright partitions (166, 168, 172) and a floor partition (178), which together form a liquid-collecting chamber that leads liquid to an outlet formed by aligned openings (190, 192) in the base wall (62) and support ring (36). The buffering assemblies (40) are joined to the bearing housing (16) of the basket shaft (14) and are joined by supports (63) to the base wall (162), enabling these structures and the basket (12) to be pre-assembled with the chambering unit (160) before being installed on the base structure (32, 34, 36). The liquid outlet (190, 192) leads into a radial liquid outflow tunnel (43) that is disposed over a radial tunnel (41) for the belt (88), thus reducing obstruction of the curb space (28) through which solids discharged from the basket top (170) fall for delivery from the machine.

Description: IMPROVED CONTINUOUS CENTRIFUGAL MACHINE The present invention relates to an improved continu¬ ous centrifugal machine of the conical basket type and is more particularly directed to an improved drive arrangement and improved arrangements of the functional components of such a machine. Continuous centrifugal machines of the conical bas¬ ket type are particularly useful for separating sugar crys¬ tals from syrup in the manufacture of sugar. Such machines typically include an upwardly open frusto-conical basket hav- ing a perforate circumferential side wall onto which a mixture of liquid and solids, for example, massecuite, is fed adjacent the small diameter end of the basket. When the basket is ro¬ tated the mixture will travel continuously toward the large diameter end under the influence of centrifugal force. A cylindrical partition concentrically surrounds the basket and has one end proximate to the large diameter end of the basket to form a liquid collecting chamber around the basket. The partition is spaced radially inward from an outer curb wall which borders an annular space for receiving and delivering downward solids that are discharged over a lip at the top of the basket. In continuous centrifugals of the type mentioned, as disclosed for instance in U.S. Patent No. 3,333,707, the bas¬ ket is secured to a shaft that is rotated by a drive belt which runs under the basket to and around a driven pulley fixed to the basket shaft. The drive belt is connected with a driving pulleydriven by a rotary prime mover such as a motor. In said U.S. patent the basket assembly is mounted for gyratory movement under the influence of imbalanced loads through resilient buffering assemblies which are lo¬ cated at the level of the driven pulley so that gyrations will take place about a point on the rotational axis at the center of the driven pulley, thus limiting overstressing of the drive belt. Further, in such known continuous centrifugal ma¬ chines the partition forming the liquid collecting chamber is connected through a vertically telescoping slip joint a rigidly fixed base structure of the machine. A liquid delivery outlet leads from this floor structure into an outlet conduit or tunnel extending radially across the solids delivery space. Operating difficulties are encountered in the use of the machinesmentioned in that gyrations of the rotating bas¬ ket assembly and/or variations of the shaft position set by the buffering assemblies cause uneven loading and wear of th drive belt. Also, the separate accommodations provided in t base structure for the drive belt and for the outflow of col lected liquid obstruct objectionally the flow of solids from the machine. Further, the arrangements of the machine struc tures are such that difficulties exist in assembling the com ponents, including inter alia difficulty in sealing the liqu collecting chamber and difficulty in assembling the rotary basket and bearing housing with the base structure of the ma chine. The principal object of the present invention is to provide an improved continuous centrifugal machine of the ty mentioned by which difficulties or shortcomings such as thos noted above can be overcome. According to one feature of the invention, the drive pulley of the machine is mounted in a fixed position below t basket shaft and is connected with that shaft through a flex ible coupling that permits angular and parallel misalignment of the axes of the basket shaft and the driven pulley. As a result, the basket shaft is unrestrained by and does not var the moment. loads of the driving belt, and the resilient buff ing assemblies are isolated from the influence of belt loads on the driven pulley. An adjustable mounting arrangement fo the driven pulley in this drive system enables the position a coupling stub shaft fixed to the driven pulley to be adapt readily to variations of the basket shaft position set by th basket mounting and buffering structures. According to another feature of the invention the ri base structure of the machine is provided with a support rin distinct from the structures that form the liquid collecting C ?I . charαber, which structures are mounted on a radial annular base wall as parts of a unitary chambering assembly that can be installed as a unit in the machine simply by seating the base wall onto and fastening it to the support ring, thus forming a liquid collecting chamber outside and beneath the basket side wall. The same base wall, moreover, has the re¬ silient buffering assemblies of the bearing housing and bas¬ ket fixed to it so that a unified assembly of the chambering unit with the basket and its shaft, bearing housing and mounting structures may be prepared and easily installed as a unit on the support ring, as well as easily removed from it and the curb of the machine for repair or maintenance. Still another feature and advantage of the invention is provided with the arrangements noted above in that a de- livery conduit or tunnel for the liquid collected in the liq¬ uid collecting chamber is provided as a stationary part of the base structure of the machine at a location overlying the belt tunnel of the drive system, with communication to this delivery tunnel through an outlet opening formed in the base wall and the support ring. Thus, difficulties of sealing liquid col¬ lecting and delivery structures are avoided and an important re duction is achieved of the surface area of structures across the solids delivery space that can obstruct the free flow of solids from the machine. Further, by virtue of the arrangements mentioned, a floor partition of the liquid collecting chamber can be sloped spirally about the bottom of this chamber to the liquid outlet opening, thus aiding the flow of collected liquid to this open¬ ing. The above mentioned and other objects, features and advantages of the invention will be further apparent from the following detailed description of an illustrative embodiment thereof, which is to be read in connection with the accompany¬ ing drawings. In the drawings: FIG. 1 is a vertical cross-sectional view of a co tinu ous centrifugal machine in accordance with the present inventio FIG. 2 is a horizontal cross-sectional view taken alon plane 2-2 in FIG. 1 but partly broken away below this plane to reveal parts in the base space of the machine; FIG. 3 is an enlarged side elevational view, partly in cross-section, of a pulley mounting assembly for adjustin the alignment of the shafts connected through the flexible coupling; FIG. 4 is a rear elevational view of parts of the adju able pulley mounting assembly; and FIG. 5 is a vertical cross-sectional view of the unita chambering structure of the machine. As shown in FIG. 1, the illustrative embodiment of the improved continuous centrifugal machine of the present inven tion is generally indicated at 10, and includes a frusto-con cal basket 12 mounted for rotation on a normally vertical ba ket shaft 14 that is supported for rotation in a bearing hou ing 16 on upper and lower bearing 18 and 20 respectively. T basket may be driven at high speed by a rotary prime mover such as a motor through an improved system for connecting th motor to the basket shaft as described below. When the machine is operated a mixture of liquids and solids to be separated is fed into the basket 12 through a s ply pipe (not shown) that extends from above the basket and charges at a location adjacent the bottom 22 of the basket. The mixture travels upwardly and outwardly along the inner s face of the frusto-conical side wall 23 of the basket under influence of centrifugal force. A perforated screen 24 is mounted adjacent the side wall of the basket, which itself i provided with suitable drain openings 25 extending therethro Thus, as the mixture travels upwardly along the side wall, c trifugal force also causes liquid constituents to travel out wardly through the screen and the side wall openings 25 for lection in a liquid collecting chamber 26 to be further descr below. Solid constituents of the mixture are discharged radi outwardly over the top edge of the basket and fall for collec through an outer solids delivering space 28 provided between outer wall of chamber 26 and a surrounding curb wall 38. A rigidly fixed supporting base structure of the centrifugal machine comprises a base ring 32, a cylindrical column 34 secured to and projecting upwardly from the base ring, and a curb support ring 100. A strong radially extend- ing support ring 36 is mounted on the upper end of the column 34 at a location spaced inward from the curb wall 38. The curb wall is secured at its lower margin to the curb ring 100. As shown in FIGS. 1 and 2, for increased rigidity, several verti¬ cal stiffening ribs 39 extend radially between the column 34 and the curb wall. Also extending between them is a radial arrangement of a belt tunnel 41 superposed by a liquid out¬ let tunnel 43. At least three resilient mounting or buffering assem¬ blies, which are generally indicated at 40 and may be of the typ described in U.S. Patent No. 3,333,707, are equally spaced apart inside the support ring 36 and a base wall 62 that forms part of a chambering unit described further below. Hangers 63 for the buffering assemblies 40 are secured by bolts 102 to an inner portion of the base wall 62. The bearing housing 16 is formed at its lower end with a surrounding support flange 42 that extends radially outward to hub formations which are parts of the buffering assemblies 40. The resilient buffering assemblies 40 interconnect the base wall 62 and the* bearing housing so that the gyratory assembly of the bearing housing, the basket shaft and the basket can gyrate to a limited extent, against resistance imposed by the elastic elements of the buf¬ fering assemblies, about a point on the axis of shaft 14 when the rotary mass of the basket with material in it is irαbalanced A large electric motor 44, the prime mover, is mounted by a suitable mounting bracket 46 to the outer side of the curb wall 38 and has a vertically arranged drive shaft 48 that car¬ ries a drive pulley 50. The drive pulley 50 drives a wide mul¬ tiple-unit V-belt 88 which extends through the belt tunnel 41 t and about a driven pulley 82 coupled wirh the basket shaft 14. According to the present invention, the driven pulley 82 is mounted in a fixed position below and substantially co- axially with the basket shaft 14, as by being fixed on a non- rotary support shaft 78 through anti-friction rotary b r£ is£t OMPI ^^° 80, and is flexibly coupled with the lower end of the bas¬ ket shaft 14 through a flexible coupling 86 which joins the shaft end with an upwardly protruding stub shaft 84 mounted on and for rotation with the pulley 82. The flexible coupling 86 directly transmits torque between the pulley 82 and the basket shaft 14 while permittin angular and parallel misalignments between the axes of the basket shaft and the stub shaft under the working conditions of the machine. A flexible coupling suitable for this purpos is available commercially, for instance as a "Dodge Paraflex" coupling. In order to establish and maintain alignment of the basket shaft with the stub shaft 84 for balanced operation of the coupling between the pulley 82 and the basket shaft 14, a adjustable mounting and positioning arrangement is provided f effecting fine adjustments of the position of the support sha 78 of the driven pulley 82 relative to the axis of rotation o the basket shaft. This arrangement, as shown in FIGS. 1-4, is supported by a mounting bracket 52 which is rigidly fixed to part of the base structureof the πvachine and has an inverted T shape formed by a vertical web portion 54 and a horizontally arranged butt plate 56. The bracket 52 holds in cantilevered relation an adjustably positioned arm 58 in which the support shaft 78 is fixed, and which holds this shaft and the pulley 8 securely in a desired set position. The arm 58 is adjustable in position relative to the butt plate 56 both radially in di rections toward and away from the driving pulley 50 and in ei direction transverse to the radial directions. For this purp the arm is provided with radially and laterally enlarged open ings 60 and is secured to the butt plate 56 by lock bolts 62 th pass through these openings and are threaded in bores tapped into the butt plate. A lug 53 depending from the mounting br ket has a set screw 64 threaded in a bore 66 of the lug, wit an end of this screw bearing radially against the outer end o the adjustment arm. The set screw 64 is held in any set posi tion by a locknut 67 which,when loosened, lets this set screw be turned to adjust the position of the adjustment arm 58 in radial direction. For setting the arm position transversely, an upstanding plate 70 is secured by bolts 72 to one side of t.e adjustment arm 58 and two set screws 74 passed through it are engaged with a side edge portion of the butt plate 56. One of the screws 74 is threaded through a tapped bore 76 in the plate 70 and bears at its end against the adjacent side edge of the butt plate 56. The other set screw 74 passes freely through a bore in the plate 70 and is threaded in a bore tapped into the adjacent side of the butt plate. Thus, by turning the screws 74, the arm may be adjusted in either direction of their motion to set the adjustment arm in a desired position within the range of adjustment provided by the enlarged openings 60. To adjust the position of the stub shaft 84 for proper driving action through the flexible coupling, the lock bolts 62 and the locknut 67 are first loosened and the set screws 74 are disengaged from the butt plate 56. By then turning the set screw 64, the arm 58 can be pushed radially in the direction away from pulley 50, or can be brought to a position radially nearer to it by the tension of the drive belt 88. The .range of radial adjustment is determined by the radial length of the openings 60 less' the diameter of the lock bolts 62. Also, the set screws 74 can be turned to set the adjustment arm trans¬ versely to any desired position within the range of adjustment provided by the width of the openings 60 less the diameter of the bolts 62. When the pulley 82 and stub shaft 84 are properl positioned for providing the required alignrrnt of the stub .shaft relative to the basket shaft, the lock nut 67 and lock bolts 62 are tightened so that the arm 58 will be held securely in the set position. The drive system provided for the machine enables a substantially uniform smooth driving action of the belt 88 to b maintained through the flexible coupling 86 and avoids the vari tions of moment loads on the belt which exist when the driven pulley is fixed to the gyratory basket shaft. Also, the resilient buffering assemblies function witho being affected by moment loads of the belt on the driven pulley - 3- To the extent that those assemblies from time to time may let a change occur in the set position of the axis of the bas ket shaft, aresultant irregularity of driving action through the flexible coupling can be compensated by an adjustment of position of the driven pulley carrying the stub shaft 84. As shown in FIGS.1 and 5, a unitary chambering struc¬ ture 160, sometimes referred to herein as a chambering unit, is supported on the support ring 36 , occupying the space betwe ring and the side wall of the basket. The chambering unit is an annular assembly that comprises a radial annular base wall 62 having a downwardly facing surface 164 which is seated on the support ring 36 and can be easily fastened to it, as by bolts 184 accessible from below the support ring. The chambe ing unit also comprises outer and inner cylindrical partition 166 and 172 which are mounted on and project upward from the base wall in concentric relation about the basket 12. The outer partition has an upper end 163 disposed adjacent the up end 170 of the side wall of the basket. The inner partition is spaced horizontally from the outer partition and has an upper end 174 disposed adjacent the lower end 176 of the bask side wall. An annular floor partition 178 located above the base wall 62 spans the space between the inner and outer partition and, with them, forms the liquid collecting chamber 26 outsid and beneath the side wall of the basket. The floor partition desirably extends spirally about the space between the vertic partitions 166 and 172 so as to lead liquid efficiently by gravity from the collecting chamber into a liquid outlet open ing (FIG. 1) formed by aligned openings 190 and -192 throu the base wall 62 and the support ring 36. The confronting su faces of wall 62 and ring 36 may be easily sealed about the o ingl90, as by a sealing cement or a gasket 182 placed between them. The upper portion of the outer partition 166 comprise a plurality of concentric rings which at their top edges are located near to a lip structure 188 at the top of the basket, thus providing a labyrinth-type seal for directing int ",0 Z- -X - liquid collecting chamber 26 the liquid thrown from the upper region of the basket side wall. The lower, smaller end 176 of the basket 12 has a skirt 189 extending outward and then downward therefrom in concentric overlapping relation to the upper end of the in¬ ner partition 172, so that liquid thrown from the lower region of the basket side wall will pass over the skirt 189 into the liquid collecting chamber. The liquid outlet opening (190, ' 192).thorough the base wall 62 and the support ring 36 delivers liquid from the collecting chamber 26 into a liquid discharge tunnel 43 extending radi¬ ally outward and downward to a liquid delivery port 194 formed in the curb wall 33. By virtue of the space height provided in the base structure of the machine for the described drive arrangement, the liquid outlet tunnel 43 can be formed as a * stationary part of the base structure that overlies and is substantially coincident with the belt tunnel 41. Consequent¬ ly a considerable reduction is achieved of the area of struc¬ tures extending across the path of fall of solids from the machine through the solids delivery space 28. This in turn reduces troubles from the accumulation of solids,- such as cen- trifuged sugar crystals, on such obstructing structures. It will be apparent from the foregoing that the cham¬ bering unit 160 is a unitary assembly of the base wall 62, the inner and the outer partitions 172 and 166 and the spirally sloped floor partition 178 and that this assembly may be easily installed by being seated in place on and fastened to the .sup¬ port ring 36. Since the base wall of this unitary assembly also provides the support for the basket assembly of the ma- chine in the arrangement according to the invention, the bas¬ ket with its shaft, bearing housing and buffering assemblies can be pre-assembled with the chambering unit so that a uni¬ tary assembly of all these components can be hoisted into the curb wall and set and fastened in operating position on the support ring 36 with the liquid outlet openings 190 and 192 aligned. Any resultant imprecision of alignment of the basket shaft with the stub shaft 84 can be overcome by adjustment of the set position of the driven pulley carrying the stub shaft. The unitary assembly of course is also removable as a unit from the base structure and the curb of the ma¬ chine in' the event of occasion to remove it for repair or maintenance. A preferred embodiment of the present invention has been illustrated in the drawings and described in detail. It will be apparent that the new features of the invention may be employed in other forms and ways and are not restri ed to particulars of the illustrated embodiment except as be required for fair construction of the appended claims.

Claims: Claims : 1. In a continuous centrifugal machine including a rigidly fixed base structure, a bearing housing, a normally vertical basket shaft journalled for rotation on bearings in said bearing housing, a basket secured to the upper end of said shaft for rotation therewith, a stationary curb wall surrounding said basket, means for resiliently mounting said bearing housing on said base structure so as to permit gyra¬ tion of said basket about a point on the axis of said shaft, and rotary drive means including a motor mounted to one side of said curb wall and means connecting said motor with the lower end of said shaft for rotating said basket, the improve¬ ment wherein said connecting means comprises: a driven belt pulley mounted for rotation in a fixed position beneath and substantially coaxially with said bas¬ ket shaft; driving belt means connecting said pulley with a driv¬ ing pulley driven by said motor; a stub shaft carried by said driven pulley for rotatio therewith and substantially aligned with said basket shaft; " an coupling means interconnecting said stub shaft and the lower end of said basket shaft for directly transmitting torqu yet permitting angular and parallel misalignment therebetween, whereby moment loads of said belt means are isolated from said bearing housing mounting means and gyration of said basket shaft does not vary the moment loads of said driven pulley on said belt means. 2. A continuous centrifugal machine according to claim 1, further comprising a non-rotary support shaft mounted in fixed position beneath and substantially aligned with said bas ket shaft, said driven pulley being supported on said support shaft through a rotary bearing thereon. 3. A continuous centrif gal machine according to claim 2, and means mounting said support shaft in fixed position yet adjustably for displacement to align said stub shaft with said basket shaft. 4. A continuous centrifugal machine according to claim 3, said shaft mounting means comprising a mount¬ ing bracket secured in fixed relation to said base struc¬ ture, an arm connected with said bracket and having said support shaft fixed thereto, said arm being displaσeable horizontally relative to said bracket in opposite direc ¬ tions radially of said curb wall and in opposite direc¬ tions transverse to said radial directions, and adjustably settable means on said bracket and said arm for displacing and setting said arm to a desired position of alignment of said stub shaft with said basket shaft. 5. A continuous centrifugal machine according to claim 4, said adjustably settable means including a set screw threaded through a bore in a part on said bracket and extending in said radial directions and having an end bear¬ ing against an end of said adjustment arm, said screw being operable to set said arm and said driven pulley in said radi directions, and set screws extending through bores in a part said arm and engaging with a part on said bracket and operab to set said arm in said transverse directions. 6. A continuous centrif gal machine according to clai 1, 2, or 3, further comprising an upwardly facing radial sup port ring mounted on said base structure inside said curb wa and surrounding said housing mounting means and an annular chambering unit supported on said support ring, said chamber unit including a radial annular base wall having a downwardl facing surface seated on said support ring, radially spaced inner and outer annular partitions mounted on and extending upwardly from said base wall and having respective upper end disposed adjacent the lower and upper ends respectively of t said side wall of said basket, and a floor partition extendi about and radially spanning the space between said annular p titions, said partitions together forming a liquid collectin chamber directly outside and under said basket wall and spac radially inward from said curb wall; and means fixing said bearing housing mounting means to portions of said base wall - - and radially inside said support ring; said bearing housing mounting means, said chambering unit, said bearing housing and said basket constituting a unitary assembly that as a unit is asse bleable onto and removable from said support ring inside said curb wall. 7. A continuous centrifugal machine according to claim 6, said outer partition comprising on an upper por¬ tion thereof means coacting with means on the upper end of said basket side wall to direct into said collecting chamber liquid thrown from the upper region of the basket, the lower end of said basket wall having means thereon extending over the upper end of said inner partition for directing liquid into said collecting chamber, said base wall and said support ring having an opening therethrough for conducting liquid from said collecting chamber, said floor partition being spaced above said base wall and sloped spirally toward said opening for flowing liquid thereinto. 8. A continuous centrifugal machine according to claim 6, said base wall and said support ring having an open¬ ing therethrough for conducting liquid from said collecting chamber, said base structure comprising a fixed liquid conduct ing tunnel extending radially away and downward from said open said base structure further comprising a radial tunnel extendi beneath and substantially coincident with said liquid conducti tunnel and through which said belt means extends between said pulleys. 9. A continuous centrifugal machine according to claim 6, 7, or 8, and means comprising a plurality of bolts extendin vertically through and accessible from beneath said support ri for securing said chambering unit in the machine. 10. In a continuous centrifugal machine including a rigidly fixed base structure, a bearing housing, a normally ve tical basket shaft journalled for rotation on bearings in said bearing housing, an upwardly open frusto-conical centrifugal basket secured to the upper end of said shaft for rota¬ tion therewith, a stationary curb wall mounted on said base structure and surrounding said basket, means for resiliently mounting said bearing housing to permit gyra¬ tion of said basket about a point on the axis of said shaft, and rotary drive means including a motor mounted to one side of said curb wall and means connecting said motor with the lower end of said shaft for rotating said basket, the improvement comprising: an upwardly facing radial support ring mounted on sai base structure inside said curb wall and surrounding said housing mounting means, and an annular chambering unit sup¬ ported on said support ring, said chambering unit including a radial annular base wall having a downwardly facing surfac seated on said support ring, radially spaced inner and outer annular partitions mounted on and extending upwardly from sa base wall and having respective upρer ** ends- disposed adjacent the lower and upper ends respectively of the side wall of sa basket, and a floor partition extending about and radially spanning the space between said annular partitions, said par titions together forming a liquid collecting chamber directl outside arid under said basket wall and spaced radially inwar from said curb wall; and means fixing said bearing housing mounting means to portions of said base wall and radially in side said support ring; said bearing housing mounting means, said chambering unit, said bearing housing, and said basket constituting a unitary assembly that as a unit is assembleab onto and removable from said support ring inside said curb w 11. A continuous centrifugal machine according to claim 10, said outer partition comprising on an upper portio thereό'f means coacting with means on the upper end of said b ket side wall to direct into said collecting chamber liquid thrown from the upper region of the basket, the lower end of said basket wall having means thereon extending over the upp end of said inner partition for directing liquid into said c lecting chamber, said base wall and said support ring having an opening therethrough for conducting liquid from said col¬ lecting chamber, said floor partition being spaced above sai - ϋT__ A G I base wall and sloped spirally toward said opening for flow¬ ing liquid thereinto. 12. A continuous centrifugal machine according to claim 10, said base wall and said support ring having an open¬ ing therethrough for conducting liquid from said collecting chamber, said base structure comprising a fixed liquid con¬ ducting tunnel extending radially away and downward from said opening, said motor connecting means including a driven belt pulley coupled with said lower end of said basket shaft and an endless driving belt connecting said pulley with a driving pulley driven by said motor; said base structure further com¬ prising a radial tunnel extending beneath and substantially coincident with said liquid conducting tunnel and through which said belt extends between said pulleys. 13. A continuous centrifugal machine according to claim 12, said driven pulley being substantially aligned axi- ally with said basket shaft and being coupled, to its lower end through a flexible coupling that permits angular and par¬ allel misalignment of the axes of said shaft and said driven pulley.

Inventors: BANGE J, HURLEY D
Applicants: WESTERN STATES MACHINE CO
Application year: 1981
Main classification: B01D21
IPC codes: B04B7, B04B9