US1903795A - Centrifugal drier - Google Patents

Description

April 8, 1933. R. w. RlGLER 1,903,795

CENTRIFUGAL DRIER 7 Filed July 18, 1930 5 Sheets-Sheet 1 Fig. i

5 INVENIOR.

RICHARD RIGLER ATTORN April 18,1933. R. w. RIGLER 1,903,795

CENTRIFUGAL DRIER Filed July 18, .1330 5 Sheets-Sheet 3 INVENTOR. RICHARD RI GLER A TTO EY.

April 18, 1933. I R. w. RIGLER 03,

CENTRIFUGAL DRIER Filed July 18, 1930 5 Sheets-Sheet 4 Fig. 4

INVENTOR. RICHARD \M RIGLER I BY fizz/chm m ATTORNEY April 18, 1933. w LE 1,903,795

' CENTRIFUGAL DRIER I Filed July 18, 1 950 5 Sheets-Sheet 5 v INVENTQR. v RICHARD VV. RIGLER BY A A TTORNEYS.

the drier.

Patented Apr. 18,1933

RICHA D W.;RIGI4ER, or rmmnmml, rE NNsr LvA NIA fcEivTnmUeAI. 1min];

' imam; fi led 1111518,

The invention relates to centrifugal driers, and to means associated therewith for purging, washing or bleaching and drying, adapted for use with coal, chemical salts, sugar, paper pulp, grains, sewage and other material." r I An object of the invention isto insure-continuous operation, so that the material being treated enters and is automatically discharged from the apparatus in a continuous stream without periodical interruptions or stopping Or'reducingthe' speed of the machine. v V 7 Another object is to provide'amethod and means to cause the material being treated as fed to theimachine to gradually pick up speed as it is being treated, thereby resulting in a saving of power for rotating the drier, avoiding injury or breaking up of fragile crystalline products being treated, and doing away with shocks, jars or vibrations to the machine due to material being treated being caused to too quickly pick up the speedof -As will be more fully explained herein after, the apparatusinclude's the customary rotary'hollow screen orbasket and a screw conveyor rotatingcoaxially with saidb'asket in "the same direction and in close proximity thereto but ata. slightly different speed. To obtain these differential speeds there has beenlempl'oyed in the past a countershaft, connected tothe respective spindles or shafts by spur, bevel, or spiral gears whichhave not been satisfactory for the following reasons: The gears mounted on the main-drive shafts rotatein a counter direction to their meshing gears on the countersh aft'and due 7 to therapidity of rotation, the teeth of the gears engage and impinge'at very high pe-aripheral speeds. Therefore extreme accuracy must be exercised in 'the manufacture to insure perfect alignment,fas otherwise un even pressure Wlll result upon the few teeth 7 that are engaged or in contact, and constant lubrication must be applied to the teeth, in

spite of which the rotation of the gears is accompanied with considerable noiseand consequent vibration. This type of drive is iwAnother object is to provide means to take .1930. Serial No. 4 3,949.

also unsymmetrical to the general design of he machine. "i 3i Another object of [the invention is to pro vide gearing that shallrotate 'noiselessly in the same direction, 'coaxially in pairs,- and 55 considerably reducing the speed at which the teeth of'the gears engage providing a greater number of teeth .inrcontact, thereby 'de-" 7 creasingthe unit tooth pressure; avoiding necessity for lubrication tol any extent; in-. creasing the efficiency of the drive and make ing'the drive symmetric'al'to the" general design of' the 'machine; obtaining-a greater number'of .tooth combinations,-thereb affording. agreater number of diflerential speeds ofthe rotary hollow-screen orba sket and the screw conveyor, and retaining the tstraight face or radial teeth of the spur gear ype I p Q 1 Another object is to automatically clean the-perforations of the rotary screen, thereby insuring continuous operation and avoid ing stoppages for cleaning purposes;

up or compensate forthe stresses and strains or vibrations 'ofthe screen lb'ask'et' and screw conveyorbwing to centrifugal movement thereof, and to uneven distribution of the material being treated due in part to uneven I feeding of the material and. in part to uneven accumulation of the driedionpartly dried material circumferentially of the screen basket. 1 .e :-'f i Another object isto provide in connection with the drier a method and meansor wash ing, purging orbleaching thematerialbeiing treated, by the introduction ofa suitable agent for thispurpose while the drying'oper ation isp'roceeding. r i

' Another object of ithe in vention is, to "pro.

' vide'means for evenly feeding'the-lniaterial to load the screen basket evenlyjofj its circum:

after setforth in the claims. 1 U y I In the accompanying drawings illustrat-: ing an embodiment of the invention, I a 100 Fig. 1 is a central longitudinal section of the machine with parts in full lines.

Fig. 2 is a side elevation of the machine.

Fig. 3 is a detail top plan View of the gear case and differential gears.

Fig. 4 is a detail fragmentary composite sectional and side view of a modification.

Fig. 5. is a detail fragmentary section on the line 5 5, of Fig. 6. v

Fig. 6 is a bottom plan view of a modification.

Fig. 7 is a detail section on the line 77 of Fig. 6, at the limit of outward movement.

In these drawings, the numeral 1 designates an electric motor, the base of which is bolted to. the housing 2, the motor shaft being coupled to center shaft 3 by coupling 4, preferably of the flexible type. The weight and thrust load upon said shaft 3 is supported by bearing 5 including a nut 6 screwed on shaft 3. This center shaft has bearing 7 in the said housing wherein it freely rotates, and at its lower end said shaft is provided with the bottom 8,, securely keyed and clamped up against a shoulder of theshaft by a suitable nut. Surrounding the shaft 3 is a tubular shaft 9', having bushings 10 in each end bearing upon shaft 3.

To the lower end of tubular shaft 9 is secured by a key, screw conveyor casting 11, having a clamping nut 12 under which is a suitable thrust bearing 13. The shaft 9 is rotatable in bearing 14 of the gear housing to be later described. 3

Cast integral and connected by the ribs orradial vanesprojecting upwardly from the periphery of the bottom 8 for the rotary hollow screen or basket is the annular diffusion rim to the top of which is bolted the lower flange17 of the rotary hollow screen or basket 15, Secured to the top. flange 19 of said hollow screen orbasket is a frusto-conical end portion or top 16 which is also of screen material.

The rotary hollow screen 15 and its frustoconical top. 16 are constructed of perforated sheet metal rolled to form and reinforced by ring flanges 17,18, 19, 20 and 21.

Both screen sections 15 and 16 are lined with the customary filtering mediums, comprising finely perforated sheet metal 22, intervened with woven wire cloth, bolted or otherwise secured thereto.

The blades or flights of the screw conveyor 11 flare at an upward angle from the periphcry of the cylindrical body thereof, the outer circumferential edges of said flights having a clearance space between the same and the inner circumferential surface of the rotary screen lining 22.

' Resting on top of the screw conveyor rim and hub 11 is a cast frusto-conical support 24, for the loading plate 25, both ofthese parts being suitably secured to thetubular shaft 9 to rotate therewith, and part 24 forming in effect a frusto-conical end for the screw conveyor, spaced from the frusto-conical top or end 16 of the rotary hollow screen.

26 designates a rolled sheet metal monitor case that is stationary and supported by the annular base 27 bolted thereon, said base having two sloping spiral troughs leading to two opposite liquor outlets.

becured to the top flange of said monitor case is a sheet metal cover plate 28, having a suitable number of vent holes 29 and supporting a cast feed hopper 30. To facilitate removal for making replacements, the case 26, cover plate 28, and hopper 30 are made in halves or sections.

Referring now to the gearing, 31 designates a spur gear of the ordinary variety, ke edto center shaft 3, and meshing with and driving internal spur gear 32. Directly below this pair of gears is a similar pair of gears of larger diameter, the teeth of which are of thespur gear type, and of which outer internal gear 33 drives inner spur gear 34, the latter being mounted fast upon the upper end of tubular shaft 9. Internal gears 32 and 33 are both keyed or otherwise secured to the inner side of the two-piece case or carrier 35. As this case or carrier 35 rotates as a unit, upper and lower extensions 37 and 38 thereof are provided with bearings 37 and 38 in the housing 2 and in the gear housing 40. The outer circumferential surfaces of both of these tubular extensions are machined concentrically with the internal gears 32 and 33, and rotate about the center axis represented by the line II1I, Fig. 3, in said bearings 37 and 38, the latter being eccentric to the bearings 7 and 14 of the housing 2, and the housing 40, and wherein the shafts 3 and 9 rotate. This eccentricity causes center shaft 3 to be located eccentrically of the interior or bore of the upper hollow extension 37 of case 35-, and tubular shaft 9 to be located similarly eccentrically of the bore of the lower tubular eX- tensions 38. Case 35 is provided with bearing support 39 upon gear housing 40.

The housing 2 for the bearings 7 and 37 and which supports the motor and the bearing 5 that carries the load of the center and tubular shafts 3 and 9, has its lower flange bolted to the flange of the gear housing 40.

In order to compensate for the stresses and strains or vibrations of the screen basket and screw conveyor, owing to centrifugal movement thereof and to uneven distribution of the material being treated, due in part to uneven feeding of the material and in part to uneven accumulation of the dried or partly dried material circumferentially of the screen basket, the gear housing 40, which has the bearing 38 for the lower tubular extension of said gear case and the bearing 14 for tubular shaft 9, and which bears the load of the housing 2, which latter has the bearing 37 for the upper tubular extension of said case and 5 42 and on thesteel frame construction .46

Obviously the motor armature shaft it: tates at the same speed as the center shaft 3 and the hollow screen or basket. carried in top plan viewalthough the direction of rotation is immaterial. -By' referring to Fig. 3 it will vbe noted that the arrangement of gearing provides that all gears rotate in the same direction and by such combinations of gear teeth as desired the tubular shaft 9 carrying the screw conveyor moves coaxially at a slower speed, the object of this differential speed beingexplained later. It should be understood however, thatby rearranging the hand of the screwconveyor or changing the direction of rotation, itwill be desirable to have the hollow screen rotate slowerth'an the screw conveyor, which can, of. course, be

readily accomplished by gear teeth combinations.

The material to be treated enters by inclined chute 48 to the charging hopper 30 whence it falls by gravity'through the. annular space between thesleeve of said' hope per and the tubular shaft 9 to the rapidly revolving loading plate 25. Centrifugal action 'thensthrows the material outwardly against the contracted upper. portion of-the conical endportion of the hollow screen, the liquid or moisture content then beginning to free itself from the material, and'passing through the filtering medium into the outer chamber located between the monitor case and'the rotary screen. The material, freed inv part from its liquid content, is retained on the inside of the conical. endiportion of the hollowscreen and is evenly distributedv thereon due to the annular frusto-conical space between the .inner and outer circum-' ferential surfaces of the frusto-conica'l screen lining 22,2 and end- 24 of theconveyor wherein the material is ifree-to slide around and to slideiradially of saidzloading plate and gradually. acquire the yeljocity of'the screen basket and screw conveyor which it does not fully acquire until it reaches; the

thereby, inasmuch as they are coupled together, the rotation being I counterclockwise portionin said frusto-fconical-space, gradu-v vertical; wall .of the hollow screen During the period of acceleration of speeddown the incline of said conical end portion, the liquidcontent is gradually freeing itself from the material and passing: through the screen.

The angle of the conical end portion of'the hollow screen is. determined by the nature of-the material beingjtreated.- 1 I Due to the action of the loading'plate 25, the frusto-con'ical .end 24 of the screw conveyor, the fr-ustorconicalx end 16. of the hollowjs'creen and-the 'frusto-conicalspace therebetweemthe material is evenly fed and distributed, around the .saidyfrusto-conical end of the screeniand so delivered to thehollow screen basket15 to evenly load the same;

Atthe juncture of the Vertical wall of the hollow screen and1the-incline of theconical end portion thereof, the screw conveyor positivelyunoves the material downwardly,- the dried material being, discharged under the diffusionrimybetween the ribs or vanes.

of thebottomi8 communicating and coming in contact with the stationary incline of the main base casting 27,at a hightangential i It willbe-noted that-the blades'bnflights of the' screw conveyor 'incline upwardly,

transversely V and are provided with: lateral 7 surfaces having anarcuate angle" wedge relative to the inner surface of the hollow "e screen thereby serving' a two-fold purpose,

first to facilitate the spreading of the material under; the. said: flights, thereby permit tingithe liquidcontent to free itself more readily; and'secondly in connection with the clearance space between the outer edges of the bladesior flights and. theinner circum 'ferential surface :of Y the hollow screen, caus ing the materialto be wedged or forced outwardly ofsaidlateral'surfacesof the flights 4 and through said clearancespace, to wipe clean }tl1e pe rforation's or strainer holes of I the screen. i 1 r Some problems demand washing, purging,

or bleaching of thefmaterial 'after it is par tially dried ,or freed of its'liquid content, this being provided for by the introduction of a trough 5 0fcast integral with the screen bottom 8, whence throughcentrifugal forceit climbs theverticalwwall of saidItrough and passes V I said wall to the interior of the hollow screw conveyor, theverticalwallcf which it climbs :through. aperforation orperforations 51of and sprays the agent through a perforation or perforations 52 of said screw conveyor between the blades of the said conveyor, upon the material.-

, Should it be desired to concentrate or separate the first run off of the liquid content of the material from the washing agent after passing through the screens, an annular shelf (not shown) could obviously be located and secured to the inside of the monitor case 26 with suitable outlets.

Fig. 4 of the drawings shows a modification wherein the hollow screen a is slightly frusto-conical instead of being cylindrical, as is also the screw conveyor 11a, the object of'this being mainly to reduce the powerrequired to force the material down the screen by the screw conveyor. An incidental advantage would be that the wedging of the material through the clearance space between the outer edges of the flights of the conveyer and the inner circumferential surface of the screen is accentuated to better wipe clean the strainer holes of the screen.

Due to the fact that the flights of the screw conveyor are of comparatively low incline, these flights are, for the clearance space stated, extended greatly in length to wi-pe clean all or practically all of the strainer holes of the screen.

Due to the wedging and spreading thin of the material through the clearance space referred to, the fluid treating medium or agent will be: more intimately mixed with the material, and due to the comparatively low incline of the conveyor flights longitudinally and the consequent greater length thereof and of the clearance space, this intimate mix- I ture will be very thorough.

g the tubular spacing sleeve 58, as well as the bottom 8a are clamped to the lower end of center shaft 3a against a shoulder by nut 63, a housing 56 being provided for said bearings l lrlfl said nut and having a dust proof cover 5- The housing 56 is provided with radial lugs perforations of which are loosely engaged by the inner ends oftangential rods 59, the outer ends of said rods being pivoted to the lower flange of base 27a at 62, and said lugs having lateral cups wherein fit elastic rubber cylinder cushions 60. The inner end of each rod 59 has a sleeve 64 loose thereon and whichthe bore of the related rubber cy1inders60 engage, the sleeve 64 being free to slide end- C5 wise and clamped at the ends by nuts 61 havapply the same to a horizontal axis apparatus or to one wherein the vertical axis is reversed from that disclosed, as will be obvious.

I claim:

1. In a centrifugal drier, a center shaft, a drier member carried thereby, atubularshaft, a drier member carried thereby, and means for rotating said shafts and members differentially including mating pairs of gears, the members of each pair being eccentric with relation to each other and the outer gears of said pairs having a common carrier.

2. In a centrifugal drier, a center shaft, a drier member carried thereby, atubular shaft, a drier member carried thereby, and means for rotating said shafts and members differentially including mating pairs of gears, the members of each pair being eccentric with relation to each other and the outer gears of said pairs having a common carrier provided with upper and lower tubular extensions within the bores of which said shafts are eccentrically located, and a housing having bearings for said shafts and bearings eccentric of the first named bearings for said tubular extensions.

3. In a centrifugal drier, means for causing material as fed to be moved in one direction to gradually acquire speed and to be partly dried and evenly distributed as it is acquiring speed, and for causing the evenly distributed partly dried material to be moved farther in the same general direction at a substantially constant speed and to be completely dried comprising outer hollow rotatable screen sections one of which is a tapering extension of and joined directly and having an obtuse angle relation to the other, and an inner rotatable screw conveyor the body of which has a tapering extension spaced from said screen tapering extension.

4-. In a centrifugal drier, an outer hollow rotatable screen, an inner hollow rotatable screw conveyor, means for causing material as fed to gradually acquire speed and be evenly distributed and partly dried and delivered to the space between said screen and said conveyor, and means for feeding a fluid treating medium between the flights at the end only of said conveyor to which the material is first fed to the evenly distributed partly dried fast moving material, said screen and said conveyor thereafter operating to completely dry the material.

5. In a centrifugal drier, an outer hollow rotatable screen, an inner hollow rotatable screw conveyor, means for causing material as fed to gradually acquire speed and be evenly distributed and partly dried and delivered r to the space between the screen and the conveyor, and means for feeding a fluid treating medium between the flights at the end only of said conveyor to which the material is first fed to the evenly distributed partly dried fast moving material, including an annular trough forming part of said screen, said conveyor having a. perforation leading to the space between the flights at the inner end thereof, and a stationary pipe discharging into'said trough.

6. In a centrifugal drier, an outer hollow rotatable screen, and an inner rotatable screw conveyor having flights provided with lateral surfaces facing in the direction in which the material is moving and having an acuteangle wedge relation to the inner surface of said screen to exert'a wedging action upon the material being-treated to force said material outwardly of said lateral surfaces towards said screen and through the clearance space between said screenand'said conveyor to wipe clean the strainer holes ofs'aid screen.

7. In a centrifugal drier, an outer hollow rotatable screen, and an inner rotatable screw conveyor having upwardly and transversely inclined flights provided with lower lateral surfaces facing in the direction in which the material is moving and having an acuateangle wedge' relation to the inner surfaceof said screen to exert a wedging action upon the material being treated to force said material outwardly of said lateral surfaces towards said screen and through the clearance space between the screen and the conveyor to wipe clean the strainer holes of said screen, the upward incline of said flights facilitating the spreading of the material under the flights and the freeing of the liquid content of the material.

8. In a centrifugal drier, means for causing material as fed to be moved downwardly to gradually acquire speed and to be evenly distributed and partly driedas it is acquiring speed, and forcausing the partly dried and evenly distributed'material to be moved farther downwardly at a substantially constant speed, and to be completely dried, comprising outer hollow rotatable screen sections one of which isa tapering extension of and joined directly and having an obtuse angle relation to the other, and an inner rotatable screw conveyor the body of which has a tapering extension spaced from said screen tapering extension, said space being of alength at least one half of that of the space between'the con- I veyor and its screen section.

Signed at Philadelphia in the county of Philadelphia and State of Pennsylvania this 5th day of July A. D. 1930. v

- RICHARD W. RIGLER.

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