US3142589A - Vertical diffuser - Google Patents

Description

Jul? 285 19.5.4' F. c. sCHAFFl-:R l-:TAL 3,1'4ZQ589- VERTICAL DIFFU'SER j I Filed May 15" 1962 I '5 Sheets-Sheet 1 INVENToRs .Robert I4/:McKenzie Francis C'. Schaffer ,Mil/MM BY L? ATTORNEYS VERTICAL DIFFUSER Filed May 16, 1962 3 Sheeizs--Sheet 2 ATTORNEYS INVENTORS Robert W McKenzie Francis C.Sckaffer v BY 1j 351 35g Fi? 54 55] WOM'W* MM July 28,1964 Y F. c scHAFFl-:R ETAL 3,142,539

- vERf'rI'cAL nIFFusER Filed 'May 1e, 1962 V s sheets-sheet s INVENTORS Robert W McKenzie Francis C-Schaer 53h 55h 1:-1' E l ATTORNEYS United States Patent O 3,142,589 v VERTICAL DIFFUSER Francis C. Schaffer, 6755 Merrydale Ave., and Robert W. McKenzie, 1836 Edinburgh Ave., both of Baton Rouge, La.

Filed May 16, 1962, Ser. No. 195,176 9 Claims. (Cl. ITI-3) This invention relates to improvements in apparatus for contacting solids or semi-solids with fluids. More particularly, this invention relates to improved apparatus for moving solids or semi-solids through or with a liquid or gas for such purposes as washing, leaching or diffusing extractable substances from the solids or semi-solids, adding substances to or reacting substances chemically with the solids or semi-solids, or transporting the solids or semi-solids in countercurrent or co-current relationship with the liquid or gas, and for other similar purposes.

Heretofore, spiral conveyors of conventional design having a single shaft and helical flights of 180I degrees or more of rotation and with or without a limited number of interruptions into which stops or projections are extended for breaking up or arresting spiral motion of the material being conveyed have proved adequate for conveying only certain types of materials. They have proved adequate in various instances for handling finely comminuted, granular or slippery materials, either in a dry state or wetted and conveyed through a liquid medium.

None of the foregoing spiral conveying arrangements is adapted to convey shredded, disintegrated or otherwise prepared short lengths of highly fibrous and stringy materials in fluid suspension. Among this latter class of materials, the reed or cane variety of plant life undoubtedly represents substantially as difficult a material to convey in fiuid suspension by means of a spiral conveyor as any other natural or artificial fibers. Other natural fibers, which are not quite as difficult to convey spirally as materials in the class of sugar cane fibers, are wood fibers or agglomerated masses of such fibers in the form of pulp derived from woody materials.

Recently, a spiral conveying device has been developed that has the ability to convey such highly fibrous and wetted materials in a vertical direction. As is more particularly described in U.S. Patent No. 2,950,998, issued August 30, 1960, the device comprises a combination of spirally arranged interrupted flights of particular dimension and pitch mounted on a single shaft for rotation and selectively spaced stationary defiectors extending radially inwardly fom a cylindrical envelope surrounding the fights. Although this device is effective in overcoming many of the conveying problems noted above, it is mechanically complicated and has a relatively narrow range of operational flexibility. Furthermore, the device requires a plurality of openings in the surrounding envelope `for the insertion of the spaced stationary deflectors. These openings constitute a severe disadvantage in that they provide pockets and ledges that allow stagnation of material and the possibility of bacteria formation and contamination.

The applicants have discovered that solids and semisolids, including many solids and semi-solids that could not heretofore be effectively transported, may be efhciently and continuously transported through a liquid or gas by a device having a unique arrangement of multiple, intermeshing, conveyor blades enclosed in a smooth-walled housing. Since the device is particularly effective in transporting solids and semi-solids through fluids in a vertical direction, and since vertical countercurrent contact with fiuids is generally the most efficient, the following detailed description of the invention is presented with particular reference to use of the device for effecting such movement. It is to be understood, however, that 3,142,589 Fatented July 28, 1964 ice this description is for the purpose of illustration only, and that many other uses of the invention are contemplated as indicated above.

Accordingly, it is an object of the invention to provide an improved form of apparatus for moving and/or diffusing particulate solid and semi-solid materials in fluid media for the various purposes indicated above.

More specifically, and in accordance with what is generally the most efiicient form of the apparatus, it is an object of the invention to provide apparatus for moving particulate solid and semi-solid materials in fiuid media in countercurrent or co-current relationship with the fiuid media; to maintain such solid and semi-solid materials in a highly dispersed state in the fluid media for intimate contact therewith; to provide apparatus for carrying out such operations on a continuous basis as regards the flow of materials delivered to and discharged from the apparatus; and to provide such apparatus in a form capable of use in a variety of different ways with a variety of different solid, semi-solid, and fluid media.

The invention is characterized by a unique arrangement of multiple conveyor fiight sectors or blades mounted on each of a plurality of parallel, rotatable shafts, surrounded by an outer housing having a cross-sectional configuration in planes normal to the aXes of the shafts that conforms closely to the envelope defined by the sets of rotating blades.

Other objects and features of the invention and its attendant advantages will be readily appreciated as the same become better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

FIG. l is an elevational view of a vertical diffuser, which is the subject of this invention, with portions of the outer housing cut away to show one of the shafts, and showing the vertical diffuser in use as an integral part of a continuous liquid-solid diffusion system, according to one aspect of the invention.

FIG. 2 is a top plan view of the vertical diffuser of FIG. 1.

FIG. 3 is a sectional View taken on line 3 3 of FIG. l showing the relationship of flight sectors in a single fiight level.

FIG. 4 is an elevational view, partly in section, of the vertical diffuser illustrated in FIG. l with the front housing removed along the line 4 4, looking in the direction of the arrows, and with portions of the screen removed for clarity.

FIG. 5 is a development of the vertical shafts of FIG. 4 showing the relationship of the flight sectors if the two front shafts of FIG. 4 are positioned on either side and in line with the back two shafts. For clarity, alternate pairs of fiignt sectors are shown to be axially rotated 90 from their true position.

FIG. 6 is a sectional view, similar to FIG. 3, showing a modification of this invention.

FIG. 7 is a sectional View, similar to FIG. 3, showing a further modification of this invention.

FIG. 8 is a development, similar to FIG. 5, showing a still further modification of the invention.

FIG. 9 is a sectional View similar to FIG. 3, showing a further modification of this invention.

FIG. 10 is a development of the vertical shafts of FIG. 9 showin g the relationship ofthe flight sectors.

FIG. ll is a sectional view similar to FIG. 3, showing a still further modification of this invention.

FIGURE l2 is a sectional View of the vertical shafts of FIG. 1l, the plane of the section being indicated by lthe line 12-12 in FIG. ll.

Referring now to the drawings in detail and panticul arly to FIGS. l and 4, the illustnated apparatus comprises a smooth-walled housing 10 having a cross-sectional configuration corresponding to an envelope about four symmetrically arranged `and partially overlapping circles. This housing is provided with upper and lower flange portions 11 and 12, respectively. The lower end of the housing 1% is connected to a suitable pan structure which, in the embodiment illustrated, comprises a` casing 13 having a crosssectional configuration that may be best described as a quadrate (square or nearly so). The casing 13 is secured to the lower flange portion 12 of the housing, preferably by means of a flange 14 and bolts, not shown. A pan bottom 15 may suitably take the shape of a dished member having a vertically extending wall portion conforming to the configuration of the casing 13 and secured thereto by bolts, not shown, passing through a flange 16 of the pan bottom and a lower flange 17 on the casing 13. The casing 13 and the vertically extending wall portion of the pan bottom 15 have somewhat greater cross-sectional dimensions, measured in planes normal to the axes of the shafts, than the corresponding cross-sectional dimensions of the housing 10, as best shown in FIGS. 3 and 4.

Within the casing 13, and substantially as an extension of the housing 10, a hollow cup-shaped screen shell 1S is provided. A vertically extending wall portion 19 of the screen shell rises above a bottom portion 2t) thereof and conforms to the cross-sectional shape of the housing 1t). The bottom portion 20 of the screen shell 18 extends laterally to engage and conform to the wall of the casing 13. The bottom portion 20 is secured or welded to the casing 13 about its circumference land is similarly secured or welded to the base of the wall portion 19 of the screen shell.

As is shown in FIGS. 3 and 4, an annular space cr chamber is thus provided between the casing 13 `and the wall portion 19 of the screen shell 18, and this annular chamber is in substantially open communication (through the outer margin of the bottom portion 20 of the screen shell) with a lower chamber between the bottom portion 2t) of the screen shell and the pan bottom 15. Fluids at the bottom of the housing 10 may flow through the screen shell into these chambers for withdrawal in a manner to be hereinafter set forth. The number and size of the holes in the screen shell provided to permit such flow will be governed, of course, by the characteristics of the particular solid, semi-solid, fibrous or agglomerated materials being conveyed. It will be appreciated that the type and thickness of the material used for the screening will also depend on the specific application, and if extremely thin gauge screening material is used, additional backing or reinforcing members between the screen and the casing 13 may be required. It will also be appreciated that the entire screen surfaces 19 and 20 may be provided in the form of a unitary and replaceable basket.

A top cover plate 22 is provided at the upper portion of the housing 10 and is secured to the flange 11 by welding or bolts, not shown. A plurality of shafts 23, 24, 25, and 26, extend through the cover plate 22, and each is journalled for rotation within and vparallel to the sides of housing 10 by a thrust bearing 27 and collar 28 located on the cover plate 22. The lower ends of shafts 23-26 are reduced, and each is received by a suitable guide bearing 29 axially aligned with the cooperating thrust bearing 27. The guide bearing 29 is supported by means of a spider arrangement 30, which is, in turn, affixed to the pan bottom 15. The shafts 23-26 are respectively rotated by a corresponding plurality of motors 31, each acting through a suitable reduction gear box 32.

About the shafts 23-26, flight sectors 33 are affixed in any suitable manner, such as by welding, in la stepped intermeshing arrangement to be hereinafter set forth. The individual flight sectors have leading and trailing edges 313 and 35, respectively. The edge that leads, of course, is dependent upon the direction of rotation of the flight sectors 33, and this direction is shown in the drawings to be clockwise (see the directional arrows in FIG. 3).

The flight sectors 33 may have either a flat or helical surface. In the case of helically formed flight sectors, the pitch of the flight sectors, that is, the angle of the outer periphery of the flights to the horizontal, may vary from zero degrees to about ninety degrees. For effective conveying, of course, the flight sectors would not be pitched at precisely zero degrees or precisely degrees but would define an angle within, but not including these limits. For a flight sector having a flat surface, the pitch angle would be the angle defined by the plane within which the flight sector lies with respect to the horizontal, and, for effective conveying, would be within the operable range as was explained above. In order to move solids or semi-solids effectively upwardly through the housing 10, a major portion of the leading edge of the flight sector 33 would be lower than the trailing edge.

Actually the pitch angle of a given flight sector is not the only determining factor as to whether a given material may be effectively moved through the apparatus. More significant is the vertical distance between the leading and trailing edges of the flight sectors 33, measured at any given point along the leading or trailing edges. For a desired vertical distance at the outer periphery of a flight sector 33, the flight pitch angle would be less for a large diameter apparatus than for a smaller diameter apparatus.

If the apparatus is to be used to process fibrous plant materials such as sugar cane cut into small discs the diameter of the cane and from about 1/16 to about one inch in length (or shredded to produce cane pieces in longer lengths but of a diameter less than that of the original cane), a vertical distance of between zero and l2 inches between the leading and trailing edges of each flight sector constitutes a practical range for a unit of moderate diameter, say 8 to 12 feet. Of course, for effective lifting and conveying, the distance would not be precisely zero, but would be a finite value up to and including l2 inches. Thus, the vertical distance between the leading and trailing edges of a flight sector may be 12 inches measured at its periphery and may decrease and approach zero for inwardly spaced points concentrically located along the leading and trailing edges. The vertical distance between concentrically located inwardly spaced points along the leading and trailing edges need not necessarily decrease from the outer periphery but may remain constant. In such a case, the pitch angle of the outer periphery of a flight sector would be less than that of an inner periphery 36.

In the embodiment illustrated in FIGS. 1-5 and 8, each flight sector 33 is a ninety degree circular segment, the inner periphery 36 of which is arcuate and has a radius complementary to the radius of its associated shaft. Also, in the embodiment illustrated in FIGS. 1-5 and 8, wherein the housing 10 has four vertical shafts 2326, each 90 degree flight sector 33 is attached to its shaft in diametrical alignment with a corresponding, opposite flight sector. Thus, as is illustrated in FIG. 3, a flight sector 33a is diametrically aligned with a flight sector 33b and has its leading edge 34 spaced ninety degrees from the trailing edge 35 of the opposite flight sector 33b. Upon rotation of a vertical shaft, each pair of flight sectors traverses a common annular flight path zone.

This invention, however, is not limited to the ninety degree flight sectors illustrated. A vertical diffuser according to this invention may have, in `one annular flight path zone, any number of flight sectors having any desired sectorial area. Thus, for example, a circular flight path area may have three 60 degree flights, four 45 degree flights, or two 77 degree flights. An annular flight path zone may contain only one. flight sector that defines an arc of more than zero and less than 360 degrees, or that forms a helical segment of more than 360 degrees.

Referring particularly to FIG. 4, shafts 23-26 are alike and only one need be described. Referring to the shaft 23, it is provided with a plurality of pairs of diametrically aligned flight sectors 33. Alternate pairs of the flight but is spaced slightly therefrom for clearance.

sectors 33 are staggered so that the leading edge 34 of a flight sector 33C is longitudinally spaced from and is directly below and in vertical alignment with the trailing edge 35 of a flight sector 33d. Similarly the trailing edge 35 of the flight sector 33C is longitudinally spaced from and is directly below and in vertical alignment with the leading edge 34 of a flight sector 33e which is in diametrical alignment with the flight sector 33d.

The diffuser may comprise one or more conveying sets of shafts and their flight sectors. In accordance with this invention, flight sectors and the shafts with which they are associated constitute one or more conveying sets. For purposes of this invention a set is used to designate at least two vertically extending parallel shafts, each shaft having flight sectors which, upon rotation, define annular flight path zones that overlap and intermesh with the flight path zones defined by the flight sectors of each other shaft in the set. Since there is an overlapping and intermeshing of flight sectors within a set, it is imperative that the annular flight path zones on one shaft do not project vertically into neighboring flight path zones on another shaft. It is also imperative that the flight sectors be arranged on the shafts so that the solids and semi-solids may be effectively conveyed from the bottom to the top of the apparatus. The flight zones in each set are therefore arranged in a stepped spiral manner.

In the embodiments shown in FIGURES l through 8, all of the flight path zones defined by the flight sectors are overlapping and intermeshing and, according to the definition previously set forth, constitute one conveying set. As can be seen more clearly in FIG. 5, the single conveying set illustrated therein includes a diametrically aligned flight pair consisting of the flight sectors 33C and 33jL on the shaft 23, and this flight pair is spaced from the flight pair consisting of the flight sectors 33d and 33e by a distance equal to the sum of the thickness of the flight path zones defined by the flight pairs consisting of the flight sectors 33g and 33h on the shaft 24, the flight sectors 331' and 33j on the shaft 25, and the flight sectors 33k and 33! on the shaft 26. Thus, it can be seen that in a single conveying set the distance between a pair of adjacent, axially aligned flight path zones (i.e., between the spaced flight path Zones on any given shaft) is equal to the total number of shafts in a set, minus one, times the vertical thickness of the zones therebetween. Added to this distance, of course, is the necessary clearance space provided between each of the overlapping flight pairs. Similar longitudinal spaces are provided between all the other adjacent flight pairs on each of the shafts 23-26. Thus, when the shafts 23-26 are positioned as is shown in FIGS. 1 4, each flight pair constitutes a step in a spiral extending from the bottom to the top of housing 10.

The housing is a smooth-walled housing free from projections and openings as is shown particularly in FIG. 3. The housing l0 conforms closely to the outer envelope of all of the flight path zones defined by the flight sectors,

This arrangement allows a continuous uninterrupted flow of solids and/or semi-solids through the apparatus and prevents stagnation and contamination of materials. As was stated above, the Vertical wall portion 19 of the screen 18 is a continuation of the housing 1t), and, therefore, has a cross-sectional configuration similarly conforming to the outer envelope of all of the flight path zones.

Near the top of the housing 10 and above the uppermost of the flight sectors 33, there is provided a discharge opening 37. This opening may'be of any convenient Size and provides a discharge exit for the spent, solid material after it has been conveyed upwardly through the entire length of the housing 10 in contact with the liquid or gaseous medium therein. The discharge of solid material from the top of the housing can be eected by means of a conventional rotary sweep having from two to four sweep arms 38 and operating from a sweep shaft 39, mounted for rotation externally of the housing 10 and parallel to the axes of the shafts 23-26 or other suitable means. The sweep arms 3S are preferably curved concave to the direction of rotation, and are in length adequate to extend from the sweep shaft 39 into the housing 10 through the opening 37 to closely adjacent the shaft 25. The sweep arms 38 are driven by a motor 40 connected through an appropriate reducer 41, to the sweep shaft 39. A collecting trough 42 is secured to the upper housing 10 at the discharge opening 37 to receive material from the sweep arms 38. Although a conventional rotary sweep conveyor of the type set forth herein is preferred in the disclosed embodiment, other discharge devices, such as a drag conveyor or a screw conveyor, may be employed.

The lower portion of the pan bottom 15 is provided with an outlet orifice 44 which is in fluid communicaiton with a T-joint 43 through an outlet pipe 45. A conduit 46 extends from one branch of the T-joint 43 and is provided with a suitable valve means 47. The conduit 46 is intended to be connected to a line for carrying off the heavier liquid medium, which will settle to the bottom of the pan 15, to a processing or reprocessing destination. The other branch of the T-joint 43 is provided with a conduit 48 having a suitable Valve means 49 provided therein. The conduit 48 is provided in the event that it is desired to withdraw from the bottom some of the heavier liquid medium which has so gravitated for recycling through the vertical diffuser.

The conduit 48 leads to an optional heat exchanger 50 of standard construction and a conduit 51 is provided between the heat exchanger 50 and a mixing hopper 52 provided with any conventional, power operated, stirring apparatus or the like, not shown. The heat exchanger 50 serves to heat the recycled liquid before re-introduction into the vertical diffuser, and the mixing hopper 52 serves to collect and mix both the heated liquid to be recycled and raw, solid materials to be introduced into the vertical diffuser. A conduit 53 leads from the bottom of the mixing hopper 52 to a conventional rotary pump 54 which is preferably of the open impeller or non-clogging type or other suitable means of injection. Solids and recycled liquid are introduced into the vertical diffuser through a conduit 55 which extends from the pump 54 through the cylindrical casing 13 and terminates in an aperture in the vertically extending wall portion 19 of the screen 18. The solids and recycled liquid are immediately subjected to the conveying action of the flight sectors 33 which will hereinafter be explained.

A countercurrent flow of liquid is established by providing a liquid inlet conduit 56 near the top of the housing 10. It is desirable to maintain a liquid level in the housing 10 which is slightly below the discharge opening 37 to prevent liquid from flowing out the discharge opening 37, but to permit the sweep arms 38 to skim off the spent solids from the surface of the liquid. This may be accomplished by either manually adjusting valves 47 and 49 to permit a liquid flow therethrough corresponding to the flow of liquid through inlet conduit 56, or by providing a suitable liquid level control device, not shown, at the desired liquid level for actuating inlet or outlet valves to automatically control the flow of liquid into or out of the vertical diffuser as required to maintain a constant level therein.

A more complete understanding of the invention will be had from a description of its operation. The fibrous or agglomerated solid material is first comminuted and preferably suspended in a portion of the liquid medium withdrawn from the vertical diffuser through conduit 48 provided for that purpose. This is accomplished in the mixing hopper 52. In the case of sugar cane, a suitable solvent, preferably hot water, is introduced into the housing through the inlet conduit 56. A portion of the sugarenriched water is drawn from the bottom of the vertical diffuser through the conduit 48, reheated by the heat exchanger 50, and is admitted to the mixing hopper 52. Raw sugar cane, cut into small discs the diameter of the cane and from 1/16 to one inch in length, is added to the mixing hopper 52 where it is comminuted and suspended in a portion of enriched liquid withdrawn from the vertical diffuser as was explained above. The heated suspension of cane chips and juice is drawn from the mixing hopper 52 by the pump 54 and fed into the screen shell 18 near the bottom thereof through the conduit 55. At the same time, the solvent is continuously introduced into the top of the housing 10 through conduit 56 as was stated above. The rate of introduction of the suspended solid material to be conveyed through the housing 1t) and the introduction of solvent at the top of the housing 10 is correlated and may be automatically controlled by automatic weighing and controlling apparatus, not shown, available commercially for such purposes.

Because of variations in the movement of particles of solid material distributed over the horizontal cross-section of the housing 1G at any given elevation or level, there is no one characteristic path that particles of solid material follow during their journey from the bottom to the top of the vertical diffuser. In general, however, suspended solid material introduced through conduit 55 would be picked up from the bottom portion 20 of the screen 1S by the leading edges 34 of the flight sectors 33e and 33j and rotated in a clockwise direction. During this rotation the solid material tends to move toward the trailing edges 35 of the flight sectors 33e and 33j on the shaft 23 and be raised so as to be picked up by the leading edges of the flight sectors 33g and 33h on the shaft 24. In the same manner, the solid material is conveyed to flight sectors 33 and 33j on the shaft 25 and from these flight sectors to flight sectors 33k and 331 n the shaft 26. The solid material, in the same manner, is conveyed back to the flight sectors of the shaft 23, where it is picked up by the flight sectors 33d and 33e thereof. The cycle is repeated by the higher flight sectors until the solid material reaches the upper surface of the fluid. In this manner the suspended solid material is moved upwardly in a slowly ascending, stepped, generally spiral pattern through the vertical diffuser. At the same time, the fluid in the vertical diffuser is following a tortuous, generally downward path.

It will be apparent that, depending upon the purpose for which the solid material is being conveyed through the fluid medium, it will be progressively washed, leached, or diffused from the cells of the solid material. In the case of sugar cane chips, sucrose is probably substantially diffused from the cells by dialysis, and liquid medium will be infused into the cells by osmosis. The material so washed, leached or diffused from the solid material being conveyed may dissolve in the fluid medium, if the latter is chosen for its solvent properties with respect to the particular solid material being conveyed, and the density of the fluid medium thereby increases. The more dense fluid medium accumulates at the lower end of the vertical diffuser for three reasons. The first reason is that the newly introduced light fluid, as its weight increases by its gradually increasing content of dissolved material, gravitates downwardly. The second reason is that fresh solid material is being introduced at the bottom of the vertical diffuser and greater soluble amounts of the solid material are immediately washed, leached or diffused in the area of initial contact with the fluid medium. A third reason in the operation suggested herein is, of course, that the fresh material is initially suspended in a recycled portion of the already concentrated fluid medium from the pan portion of the vertical diffuser.

As the shafts slowly rotate in the direction indicated and suspended solid, fibrous, or agglomerated materials are conveyed upward through the fluid medium, the material is placed continuously in contact with fluid of less and less concentration, whereby, because of the laws governing dilution or the laws governing the interfacing Cil u of fluids of different densities, the dynamic forces tend to carry the materials of higher concentration into the fluid medium of less concentration so that increasingly greater total percentages of materials have been washed, leached, or diffused from the solid material as it moves toward the upper end of the vertical diffuser where the fresh solvent medium is being introduced.

The height of the vertical diffuser and speeds of rotation of the shafts for any given diameter unit determine the quantity of solid material that can be conveyed through the vertical diffuser per unit time. Although the vertical diffuser is initially designed in height for a specific solid material or group of solid materials to be treated therein, a great degree of latitude may be had for different solid materials in this type of device in that the contacting time may be varied up or down by the adjustment, within limits, of the speeds of the shafts. The relationship is, of course, direct as will be apparent, so that the through-put tends to vary directly with the speed of rotation of the shafts, and the contacting time tends to vary inversely with the speed of rotation of the shafts, although it will be understood that such variations are not necessarily straight line relationships.

The solid materials conveyed through the diffuser ultimately reach the uppermost flights of a shaft, which in the embodiment illustrated in FIGS. l-5, would be the uppermost flight pair affixed to the shaft 25. At this time, due to the correlation of the height of the vertical diffuser, the liquid media therein, and the speed of rotation of the shafts, the solid materials are satisfactorily washed, leached, or diffused as the specific case may be, and are ejected from the vertical diffuser through the discharge opening 37 by the sweep arms 38.

Preferably the shafts operate at the same speed and in the same direction. However, if dead spots occur in the fluid-solid suspension because of equal pressures induced by equal speeds, the speeds of different shafts may be varied to insure continuous movement and dispersion of the solids. In some instances, moreover, it may be desirable to drive one shaft at a much faster speed than the others. This shaft would act as a stirrer while the remaining shafts would effect the countercurrent motion of the solids as explained above.

According to another aspect of this invention, a plurality of intermediate flight sectors or blades 57 may be affixed to each shaft midway between each flight pair. Thus, in FIG. 8, the shaft and flight sector arrangement is identical to that shown in FIG. 5, except that on each shaft an intermediate flight sector 57 is affixed to the shaft midway between the flight pairs. If a diametrically aligned pair of intermediate flight sectors 57 are affixed to a shaft 58 midway between two pairs of flight sectors 33m-3311 and 33o-33p, however, they would, upon rotation, define intermediate flight path zones that would lie in the same plane as the flight path zone defined by a pair of flight sectors 33g and 331' on shaft 59. This is true of all the intermediate flight sectors 57. It is necessary, therefore, to reduce the radial size of all the intermediate flight sectors 57 so that they will clear the coplanar flight sector. These intermediate flight sectors are intended primarily to prevent dead spots between flight sectors on the same shaft, although they may be designed to effect some lifting and conveying action.

The invention is not limited to the preferred embodiment illustrated in FIGS. 1-5 and 8 and described above where the vertical diffuser is provided with four shafts. FIG. 6 illustrates a single conveying set, two-shaft diffuser having a plurality of 45 degree flight sectors 33s. The shafts 60 and 61 are parallel and are vertically extending. Similar to the preferred embodiment, a smoothwalled housing 10a conforms closely to the outer envelope of all of the flight path zones defined by the flight sectors 33s, but is spaced therefrom for clearance. The flight sectors 33s are intermeshing and convey solids in 9 a stepped spiral path similarly to the preferred embodiment.

FIG. 7 illustrates a cross-section of a single conveying set, vertical diffuser having three parallel and vertically extending shafts 62, 63, and 64 with spaced, intermeshing Hight sectors 33t. A smooth-walled housing 10b conforms closely to the outer envelope of all of the Hight path zones defined by the Hight sectors 33t, but is spaced therefrom for clearance.

FIGURES 9 through 12 illustrate vertical diffusers having multiple conveying sets according to a further aspect of this invention. FIG. 9 illustrates a cross-section of a vertical diffuser having seven parallel and vertically extending shafts 65, 66, 67, 68, 69, '70, and 71. Mounted on these shafts are spaced intermeshing, Hight sectors 133a, 13312, 133e, 133d, 133e, 133i, and 133g. These Hight sectors are shown to be of varying sectorial areas to illustrate that the Hight sectors in a single set or multiple set vertical diffuser need not be identical.

The seven shaft vertical diffuser of FIG. 9 comprises six conveying sets which are composed of the radially aligned Hight sectors of the shafts 65, 66, and 67; 65, 67, and 68; 65, 68, and 69; 65, 69, and 70; 65, 70, and 71; and 65, 71, and 66, respectively. In a single conveying set, the distance between adjacent, axially aligned Hight path zones is equal to the total number of shafts in that set, minus one, times the vertical thickness of the Hight path zones. Thus, as can be seen in FIG. 10, in the conveying set comprising the shafts 65, 66, and 67, the distance between the axially aligned Hight path zones deHned by the flight sectors 133:1 on the shaft 65 is equal to the number of shafts in that set, minus one, times the vertical thickness of the zones. Added to this distance, of course, is the necessary clearance space provided between each of the overlapping Hight sectors.

FIG. 1l illustrates a cross-section of a vertical diffuser having three parallel and vertically extending shafts 72, 73, and 74. Mounted on these shafts are spaced intermeshing, Hight sectors 133k. The three shaft vertical diffuser of FIG. 11 comprises two conveying sets, as distinguished from the one-set, three-shaft, vertical diffuser of FIG. 7. The two conveying sets are defined by shafts 72 and 73, and 72 and 74, respectively. In a single conveying set in FIG. l2, the distance between the axially aligned Hight path zones defined by the Hight sectors 133k is determined by the previously explained formula.

Although the invention has been described with particular reference to the use of the apparatus for effecting vertical countercurrent motion between solids and Huids, the utility of the apparatus is not limited thereto. The apparatus may be employed to effect chemical reactions between solid and Huid substances, to desiccate wet solids or to wet dry solids. Co-current How for any of the above purposes may be carried out by introducing both the Huid and solid substances, under pressure, at the lower end of the housing, and providing a suitable Huid and solid discharge aperture near the top of the housing. The apparatus, in some instances, need not be vertical and may even be horizontally disposed, although, as was explained above, a vertically disposed apparatus is generally most eHicient for countercurrent, Huid-solid contact.

The form of the invention described herein is intended to be illustrative and the invention should not be considered as limited except as defined in the following claims.

What is claimed is:

l. Apparatus for moving solid and semi-solid materials in fluid media, comprising at least two vertically extending parallel shafts journalled for axial rotation, a multiplicity of radially extending flight sectors, each having a leading and trailing edge, mounted on each of said shafts and, upon rotation of said shafts, defining annular Hight path zones, said flight path zones of each shaft overlapping and intermeshing with the flight path zones defined by the Hight sectors of at least one other shaft and each flight path zone being axially spaced from adjacent flight path zones on the same shaft, each flight path zone being occupied only by the flight sectors of a single shaft, and a vertically extending smooth-walled housing enclosing said shafts and said flight sectors, said housing conforming closely to the outer envelope of all of said flight path zones.

2. Apparatus for moving solid and semi-solid materials in fluid media, comprising at least two vertically extending parallel shafts journalled for axial rotation, a multiplicity of radially extending Hight sectors, each having a leading and trailing edge, mounted on each of said shafts and, upon rotation of said shafts, defining annular flight path zones, said flight path zones of each shaft overlapping and intermeshing with the Hight path zones defined by the flight sectors of at least one other shaft and each flight path zone being occupied only by the Hight sectors of a single shaft and being axially spaced from an adjacent flight path zone on the same shaft a distance corresponding to the total thickness of the overlapped flight path zones therebetween, and a vertically extending smooth-walled housing enclosing said shafts and said flight sectors, said housing conforming closely to the outer envelope of all of said flight path zones.

3. Apparatus for moving solid and semi-solid materials in fluid media, comprising at least two vertically extending parallel shafts journalled for axial rotation, a multiplicity of radially extending flight sectors, each having a leading and trailing edge, mounted on each of said shafts and, upon rotation of said shafts, defining annular flight path zones, said flight path zones of each shaft overlapping the flight path zones defined by the flight sectors of each other shaft and each flight path zone being occupied only by the flight sectors of a single shaft and being axially spaced from an adjacent flight path zone on the same shaft a distance corresponding to the total number of shafts, minus one, times the vertical thickness of said flight path Zones therebetween, and a vertically extending smooth-walled housing enclosing said shafts and said flight sectors, said housing conforming closely to the other envelope of all of said flight path zones.

4. Apparatus for moving solid and semi-solid materials in Huid media, comprising at least one set of shafts and associated flight sectors for conveying said materials in an ascending, stepped, generally spiral pattern, each such set comprising at least two vertically extending parallel shafts journalled for axial rotation, a multiplicity of radially extending flight sectors, each having a leading and trailing edge, mounted on each of said shafts and, upon rotation of said shafts, defining annular flight path zones, said flight path zones of each shaft overlapping and intermeshing with the flight path zones defined by the Hight sectors of each other shaft in said set and each flight path zone being axially spaced from adjacent flight path zones on the same shaft, each flight path zone being occupied only by the flight sectors of a single shaft, and a vertically extending smooth-walled housing enclosing said shafts and said Hight sectors, said housing conforming closely to the outer envelope of all of said Hight path zones.

5. Apparatus for moving solid and semi-solid materials in fluid media, comprising at least one set of shafts and associated Hight sectors for conveying said materials in an ascending, stepped, generally spiral pattern, each such set comprising at least two vertically extending parallel shafts journalled for axial rotation, a multiplicity of identical radially extending Hight sectors, each having a leading and trailing edge, mounted on each of said shafts and, upon rotation of said shafts, defining a plurality of identical annular Hight path zones, said Hight path zones of each shaft overlapping and intermeshing with the Hight path zones defined by the Hight sectors of each other shaft in said set and each Hight path zone being occupied only by the Hight sectors of a single shaft and being axially spaced from an adjacent Hight path zone on the same shaft a distance corresponding to the total thickness of i. l the overlapped Hight path zones therebetween, and a vertically extending smooth-walled housing enclosing said shafts and said Hight sectors, said housing conforming closely to the outer envelope of all of said Hight path zones.

6. Apparatus for moving solid and semi-solid materials in fluid media, comprising at least one set of shafts and associated Hight sectors for conveying said materials in an ascending, stepped, generally spiral pattern, each such set comprising at least two vertically extending parallel shafts journalled for axial rotation, a multiplicity of identical radially extending Hight sectors, each having a leading and trailing edge, mounted on each of said shafts and, upon rotation of said shafts, defining a plurality of identical annular Hight path zones, said Hight path zones of each shaft overlapping the Hight path zones defined by the Hight sectors of each other shaft in said set and each Hight path zone being occupied only by the Hight sectors 0f a single shaft and being axially spaced from adjacent Hight path zones on the same shaft a distance corresponding to the total number of shafts in said set, minus one, times the vertical thickness of a Hight path zone, and a vertically extending smooth-walled housing enclosing said shafts and said Hight sectors, said housing conforming closely to the outer envelope of all of said Hight path zones.

7. Apparatus for moving solid and semi-solid materials in Huid media, comprising at least two vertically extending parallel shafts journalled for axial rotation, a multiplicity of radially extending Hight sectors, each having a leading and trailing edge, mounted on each of said shafts and, upon rotation of said shafts, defining annular Hight path zones, said Hight path zones of each shaft overlapping and intermeshing with the Hight path zones defined by the Hight sectors of at least one other shaft and each Hight path zone being axially spaced from adjacent Hight path zones on the same shaft, each Hight path zone being occupied only by the Hight sectors of a single shaft, said Hight sectors having a pitch angle so that the leading edge of a Hight sector is lower than the trailing edge of said Hight sector by a vertical distance of between zero and 12 inches, and a vertically extending smooth-walled housing enclosing said shafts and said Hight sectors, said housing conforming closely to the outer envelope of all of said Hight path zones.

8. Apparatus for conveying solid and semi-solid materials upwardly through Huid media, comprising at least two vertically extending parallel shafts journalled for axial rotation, a multiplicity of radially extending Hight sectors, each having a leading and trailing edge, mounted on each of said shafts and, upon rotation of said shafts, de-

Hning annular Hight path zones, said Hight path zones of each shaft overlapping and intermeshing with the Hight path zones defined by the Hight sectors of at least one other shaft and each Hight path zone being axially spaced from adjacent Hight path zones on the same shaft, each Hight path zone being occupied only by the Hight sectors of a single shaft, a vertically extending smooth-walled housing enclosing s'aid shafts and said Hight sectors and conforming closely to the outer envelope of all of said Hight path zones, a screen through which Huid media may be withdrawn from said housing having a vertically extending portion attached to the lower end of said housing enclosing the lower Hight sectors and conforming closely to the outer envelope of all of said Hight path zones and having a bottom portion underlying the lowermost Hight path zone, means comprising a casing and a pan enclosing and spaced outwardly from said screen, a conduit extending from said pan for withdrawing Huid media from said housing through said screen, inlet means extending through said casing and said screen for introducing solids into said housing, Huid inlet means extending through the upper end of said housing and discharge means at the upper end of said housing.

9. Apparatus for conveying solid and semi-solid materials upwardly through Huid media, comprising at least two vertically extending parallel shafts journalled for axial rotation, a multiplicity of radially extending Hight sectors, each having a leading and trailing edge, mounted on each of said shafts and, upon rotation of said shafts, defining annular Hight path zones, Said Hight path zones of each shaft overlapping and intermeshing with the Hight path zones defined by the Hight sectors of each other shaft and each Hight path zone being axially spaced from an adjacent Hight path zone on the same shaft, each Hight path zone being occupied only by the Hight sectors of a single shaft, a plurality of intermediate Hight sectors, radially mounted on each of said shafts and, upon rotation of said shafts, defining intermediate Hight path zones located substantially midway between pairs of adjacent axially spaced Hight path zones, and a vertically extending smooth-walled housing enclosing said shafts and said Hight sectors, said housing conforming closely to the outer envelope of all of said overlapping and intermeshing Hight path zones.

References Cited in the file of this patent UNITED STATES PATENTS 2,857,907 Kaether et al. Oct. 28, 1958 2,885,311 Brunicke-Olsen et al May 5, 1959 2,950,998 Stewart et al. Aug, 30, 1960

Claims (1)

1. APPARATUS FOR MOVING SOLID AND SEMI-SOLID MATERIALS IN FLUID MEDIA, COMPRISING AT LEAST TWO VERTICALLY EXTENDING PARALLEL SHAFTS JOURNALLED FOR AXIAL ROTATION, A MULTIPLICITY OF RADIALLY EXTENDING FLIGHT SECTORS, EACH HAVING A LEADING AND TRAILING EDGE, MOUNTED ON EACH OF SAID SHAFTS AND, UPON ROTATION OF SAID SHAFTS, DEFINING ANNULAR FLIGHT PATH ZONES, SAID FLIGHT PATH ZONES OF EACH SHAFT OVERLAPPING AND INTERMESHING WITH THE FLIGHT PATH ZONES DEFINED BY THE FLIGHT SECTORS OF AT LEAST ONE OTHER SHAFT AND EACH FLIGHT PATH ZONE BEING AXIALLY SPACED FROM ADJACENT FLIGHT PATH ZONES ON THE SAME SHAFT, EACH FLIGHT PATH ZONE BEING OCCUPIED ONLY BY THE FLIGHT SECTORS OF A SINGLE SHAFT, AND A VERTICALLY EXTENDING SMOOTH-WALLED HOUSING ENCLOSING SAID SHAFTS AND SAID FLIGHT SECTORS, SAID HOUSING CONFORMING CLOSELY TO THE OUTER ENVELOPE OF ALL OF SAID FLIGHT PATH ZONES.

Images