US1235193A - Centrifugal drier. - Google Patents

Description

` G. H. ELMORE.

CENTRIFUGAL DINERr APPLICATION FILED SEPT. 6. 1912.

Patented July 31, 1917.

4 SHEETS-SHEET l.

w d M vall /lll/l/ wwwa/6- G; H. ELMORE.

CENTRIFUGAL DRIER.

APPLICATION FILED SEPT. 6. 1912.

Patented July 31, 1917.

4 SHEETS--SHEET 2 G. H. ELMORE.

CENTBIFUGAL DRIER.

APPLICATION man SEPT. 6. 1912.

1,285, 1 93. Patented July 31, 1917.

4 SHEETS-SHEET 3.

UNITED sTATEs PATENT oFmcE.

GUY H. ELMORE, 0F SWABTHMORE, PENNSYLVANIA.

CENTRIFUGAL DRIEB.

To all lwhom z't may concern.'

Be it known that I, GUY H. ELMORE, a citizen of the United States, residing at Swarthmore, in the county of Delaware and State of Pennsylvania, have invented certain -new and useful Improvements in Centrifugal Driers, of which the following isa specication.

This invention relates to centrifugal driers primarily intended for drying granular materials such as coal, but also adapted for use in drying wet pulpy masses such as finely divided ores prepared for use in cya.- nid processes and the like.

This invention relates more particularly to the conical form of the rotary screen and to the form of the conveyer blades for use with this screen to effect an easy feed and discharge. Other details of improvement relate to the sectional construction of the screens whereby replacements are readily made, the reduction in the number of parts,

and the general simplification of the device.

to adapt it to commercial use.

In the drawings: v

Figure 1 is a vertical axial section of the complete device;

Fig. 2 is a section on the line II-H of Fig. 1;

Fig. 3 is an elevation of the' rotating'` screen structure, showing the mode of -attaching the removable screen sections;

Fig. 4 is an enlarged section on the line IV-IV of Fig. 3;

Fig. 5 is a part axial section and part elevation of the conveyer or feeder member; and

Fig. 6 is a section on the line VI-VI of Fig. 3.

The mainframe and housing of the ma.- chine consists of a cylindrical casting 1, having the duct 2 around its bottom through which the water extracted in the drier may flow to discharge spout 3. A manhole 4 gives access to the interior of the housing for the inspection and repair of the screen rotor. The duct 2 is formed around thelr outside of a curved discharge guide-plate 5,

which is cast integrally with housing 1.,andv

which receives the solid material discharged fromvthe screen rotor and deiects it into the discharge spout 6 bolted to housing 1. The lower bearing 7 for the main shaft is car-A ried at the center of a spider-frame 8 also Specication of Letters Patent.

Patented Julyr 31, 1917.

Application led September 6, 1912. Serial N o. 718,931.

ing 13, and the differential gear-housing 14.

The cap-plate 15 of the housing 14 is provided with a bearing 16 and a thrust-bearing 17. The main shaft 18 of the drier turns in the bearings 7 and 1.6, and is sustained upon thrust-bearing 17 by a split collar 19 clamped in a groove in said shaft. A sleeve 20 surrounding shaft 18 turns at its upper end in a bearing 21 in plate 12, and at its lower end turns on said shaft 18, the sleeve being lined at 22 with Babbit metal. This sleeve 20 is supportedupon thrust-bearing 13 by means of a split collar 23 clamped on said sleeve. The shaft 18 carries the screen rotor, While the sleeve 20 carries the cnveyer rotor or feeder. i

The shaft 18 is driven by any suitable mechanism, and the sleeve 2O is driven from shaft 18 in the same direction but at somewhat slower speed, by the differential gears 24, 25, 26 and 27, the gears 24 and 25 being keyed on sha-ft 18 and sleeve 20 respectively, while gears 26 and 27 are keyed to a jackshaft 28 turning in bearings 29 on gearhousing 14.

The screen rotor is keyed on the shaft 18, and is further held by a split collar 30.- The rotor frame is cast in one piece, and consists of the hub 31, radial spokes 32 of the form shown in the drawing, base ring 33 provided with the water guard flanges 34 and 35 which straddle the inwardly extending rim of discharge guard-plate 5, the top ring 36, and the inclined uprights 37, all as shown clearly in Figs. 3 and 6. As is most clearly suited for granular materiah'but I contemplate mounting in frames 40v any of the well known filtering mediums or fabrics, which may be better suited to the drying of pulps or other materials. The frames 40 are inserted and fit closely in the openings bounded by the top ring 36, bottom ring 33, and inclined uprights 87. They are held in place by yokes 44 and bolts 45 passing through the uprights 37. The top of the screen rotor is closed by an annu-lar plate 46 bolted thereto and surrounding the hopper 10.

The screen rotor thus forms a conical perforate shell, and fthe angle of the element of the cone to the axis is a function of the character of material to be handled, the normal speed of rotation of the rotor, etc. The angle is determined by experiment according to the following theoretical considerations. Material passing through the screen rotor is subjected to centrifugal force acting horizontally, and to gravity acting vertically. The resultant of the two forces acting upon a particle of material at any one instant acts downward and outward, and will make some angle with the element of the rotor cone. Obviously the resultant force exerts a downward feeding. tendency which varies with the value of G), and there is some vlimiting value of at which the material will just begin to feed .itself slowly through the rotor. This value such a value for (d `that the feeding tendency vis not ever sufficient to actually cause a feeding, but is suiiicient to relieve the mechanical conveyer or feeder of practically all load. By thismeans I secure a relatively free running device, With all the advantages of mechanical feed.

This mechanical feed is effected by a bellshapedconveyer rotor 47 keyed on sleeve 20, and further held thereon by a split collar 48. Formed above the bell 47, but integrally with it, are stirrer arms 49,l and formed on the bell are helical ribs 50, both I' -designed to secure an even distribution of vwith reference to the direction of rotation of the bell 47, Aso that when the machine is running, since the screen rotor moves the faster, the flights 51 tend to feed the contained material downward. As previously explained, this feeding is attained without overcoming very .great resiStance,-yet `serves to control the rate of feed positively. v.

After the flights 51 have forced the material olf the screens it reaches the conical, surface 52, which has a greater inclination so that the material automatically flows over it to the guard plate 5 and hopper G.

From the foregoing description itlwill bc observed that the design of my device is such as toy produce a very free running mechanism, and one which can be manufactured at comparatively small expense.

The particular-construction of the Vscreen that the screen be given a true conical form as it might for example be given a conoidal form and still operate in substantially the manner described, the essential feature of my invention being the use of a progressively increasing screen diameter toward the discharge end in such manner to effect the free feeding action described, in combination with a quick pitch conveyer rotor to control the feed. The term quick pitch as used in the specification and claims with reference to the flights of the conveyer rotor is used to define pitches in which the longitudinal feed for one revolution is equal to or greater than the circumferential path of the flights.

Having thus described my invention, what I claim is l. In a centrifugal drier, the combination of a rotatable, substantially conical screen; means for feeding material to be dried to the smaller end of said screen; a conveyer rotor mounted to rotate substantially coaxially with said screen and having quick pitch substantially helical conveyer ights turning in close proximity to said screen; and means for rotating said screen and lconveyer rotor in the same direction and at slightly unequal speeds, the angle of flare of the screen and its normal speed of rotation being so cordinated that the resultant tendency of the material undergoing treatment to .flow is nearly but not quite sufficient to feed said material along said screen. l

2. Ina centrifugal drier the combination of a substantially conical screen, rotatable upon a vertical axis and mounted with its vlarger end downward; means for feeding material to be dried tothe upper end of said screen; a conveyer rotor mounted to rotate substantially `coaxially within said screen and having substantially helical conveyer flights in close proximity to the screen; and means for rotating said screen and conveyer rotor in the same direction and at slightly unequal speeds, the angle of flare of the screen and its normal speed of rotation being. so cordinated that the feeding tendency produced by gravity and centrifugal force is nearly but not quite sufficient to feed the material treated in said drier downward along the said screen.

3. In a centrifugal drier, the combination of a supply hopper; a downwardly Haring substantially conical centrifugal screen drum mounted to rotate on a vertical axis beneath said hopper; a bell shaped distributer mounted to rotate within said screen about a common axis therewith,'said distributer bein of substantially the same diameter as said hopper; a plurality of quick pitch, substantially helical conveyer flights mounted on the periphery of said distributer and moving in close proximity to said screen; spiral distributing ribs carried by the upper surface of said distributer and adapted to exert an outward feeding tendency on material in said hopper; stirrer arms mounted to turn with said distributer in the mouth of said hopper; and means for driving said screen and distributer in the same direction at slightly unequal speeds.

4. In a centrifugal drier, the combination of a supply hopper; a downwardly flaring substantially conical centrifugal screen drum mounted to rotate on a vertical axis beneath said hopper; a bell shaped distributer mounted to rotate within said screen.

.said distributer in the mouth of said hopper; and means for driving said screen and distributer in the same direction at slightly unequal speeds.

5. In a centrifugal drier, the combination of a supply hopper; a downwardly flaring substantially conical centrifugal screen drum mounted to rotate on a vertical axis beneath said hopper; a bell shaped distributer mounted to rotate within said screen about a common axis therewith, said distributer being of substantially the same diameter as the hopper; a plurality ofquick pitch, substantially helical conveyer flights mounted on the periphery of said distributer and moving in close proximity to said screen; and means for driving said screen and distributer in the same direction at slightly unequal speeds, the angle of flare of the screen and its normal speed of rotation being so coordinated that the feeding tenden'cy caused by gravity and centrifugal force shall be nearly but not quite suiiicient to cause a feed of the treated material down said screen.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

GUY H. ELMORE.

Witnesses:

H. V. CRoLL, ANTHONY 'GRoT'rHUs

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