US1829547A - Centrifugal process and apparatus - Google Patents

Description

Oct. 2?, 1931. 1. P. SHARPLES 1,829,547

CENTRIFUGAL PROCESS AND APPARATUS Filed March 11, 1927 3 Sheets-Sheet 1 Oct. 27,1931. P. SHARPLES CENTRIFUGAL PROCESS AND APPARATUS Filed March 11, 1927 3 Sheets-Sheet 2 8 auto; Milka/ L 351 2 Swot 2;, W

| P. SHARPLES 1,829,547

CENTRIFUGAL PROCESS AND APPARATUS 3 Sheets-Sheet 3 Oct. 27, 1931.

Filed March 11, 1927 Patented 0st. 27, 1931 UNITED STATES PATENT OFFICE LAURENCE P. SHARPLES, OF CHESTER, PENNSYLVANIA, ASSIGNOR TO THE SHARPLES SPECIALTY COMPANY, OF PHILADELPHIA, PENNSYLVANIA, A CORPORATION OF DELAWARE CENTRIFUGAL PROCESS AND APPARATUS Application filed March 11, 1927. Serial 1T0. 174,721.

This invention relates to a process and apparatus for the centrifugal separation of liquids from a mixture therewith of solid particles.

In the separation of liquids from solids by centrifugal force it is desirable that the separating operation shall be continuous, and that the apparatus employed shall be so constructed that the separation will be, complete to a desired degree, and desirable that the solid constituent of the mixture shall be effectively discharged continuously.

Centrifugal machines have been proposed that are capable to a limited degree of separating specific mixtures of liquids and solids 'but it is desirable to have a process and apparatus for the separation of liquids from solid particles, that are capable of general or at least broad application to mixtures of varying characteristics and composition.

In the centrifugal separation of liquids from solids it is desirable that the separating mechanism may be so constructed as to have ,a large capacity but it is desirable to avoid the consumption of excessive quantities of power and it is therefore desirable to discharge the liquid constituent of the mixture from the centrifugal machine by the application thereto of as'little power as possible.

In the separation of liquids from solid particles by centrifugal force it is desirable to remove the liquid from solid particles to as complete a degree as possible and also to prevent contamination of the solid particles by subsequent addition thereto of liquids or moisture as by contacting with the dried solid particles steam or vapor or a mist of the liquid constituent in the mixture.

In centrifugal machines in which two con- I tacting or adjacent parts are moved at differential speeds. and particularly where one of such parts controls or effects relative motion between the centrifugal rotor and the solid constituent of the mixture, jamming of solid particles between such parts and other irregularities of operation cause injury-to the mechanism if the parts are positively driven at differential speeds, and it is therefore desirable that the differential drive for such parts shall be non-positive in operation.

It is an object of my invention to provide a process and apparatus for the centrifugal separation of liquids from solid particles, in which will be embodied the desirable features above set out and other desirable features set forth in or apparent from the following description and in which undesirable features of operation will be avoided.

In the practice of my invention a mixture of liquid and solid particles is introduced into a rotating shell or basket and the liquid is separated from the solid particles and discharged from the shell or basket by centrifugal force and the centrifugal force imparts to the solid particles. a tendency to move toward and to discharge from a, predetermined part of the shell or basket but that tendency is so controlled or retarded as to ensure centrifugal removal of liquids from solid particles to a desired degree and then the particles are discharged from the shell or basket under the action of centrifugal force. Thus, in the embodiment of my invention described herein for the purpose of assisting in the understanding of my invention, a rotating shell or basket is employed that is so constructed that centrifugal force separates the liquid from the solid particles and discharges the liquid from the shell or basket and the centrifugal force tends to cause the solid particles to move toward and discharge from their intended point of discharge, and means is provided to control or retard that movement and discharge of the solid particles. For example, the rotating shell or basket may be perforated to facilitate the centrifugal separation and discharge of the liquid and its walls may be inclined to the axis of rotation, as by making the shell or basket generally conical in form, to the end that centrifugal force will tend to move the solids toward and to discharge them from the basket or shell at its largest diameter, and a particular means for controlling or retarding such movement and discharge of the solid-s may be a spiral blade or plate that is engaged by the solid particles and which is rotated at a slow speed with respect to the shell or basket and permits the solid particles to advance at any desired rate under the action of centrifugal force toward their P oint of discharge from the shell or basket.

11 accordance with my invention the pitch 1 or basket. I Also, in accordance with my invention the rotatin shell or basket includes a section or zone '0 small Y diameter, preferably of the minimum practical diameter, into which the 7 mixture of liquid and solid particles is first introduced and from which the major portion of the liquid is discharged from the rotating shell or basket at a low peripheral speed and before that major portion of the liquid has had done upon it that amount of work necessary to bring it to' the peripheral speed of those parts of the rotating shell orbasket that are of relatively large diameter.

And, in accordance with my invention a current of heated or dry gas of suitable chemicahneutrality ,or-activity may be passed in such-manner anddirection as to prevent steam or vapor from the mixture or a mist of the liquidfrom coming into contact with the solid particles discharged from the centrifugal machine; and such current of air or gas may be flowed into contact with, or counter to,'the solidparticles discharged in disoersed form from the rotating shell or basket by centrifugalforce.

To the end that the. apparatus may not be injured by the jamming of solid particles be- \-tween the centrifugal shell or basket and the spiralzor other device that controls, retards or. effects the movement of the solid particles with respect to the shell or basket my invention includes the driving of the shell or basket and the spiral at different speeds by belt-gearing which belt-gearing may include variable speed belt-gearing.

A further development of my invention consists in providing a centrifugal rotor of the type used for draining or straining and in which-those parts that resist the centrifugalforce are protected against the action of corrosive substances treated in or discharged from the centrifugal rotor.

Other and further objects of my invention Wlll appear from the following description of an illustrative embodiment of apparatus embodying my invention whereby my process may be practised, it being understood that my invention is not limited to the details ofconstruction and operation shown and described but includes such modifications thereof as fall within the spirit of my invention.

In the drawings, in which similar reference characters indicate like parts,

Fig. 1 is a vertical sectional view taken on the line 1--1 of Fig. 2, of apparatus embodying my invention, and whereby my process may be practised;

Fig. 2 is a horizontal section on the line 22 of Fig. 1;

Fig. 3 is a partial detailed view of the centrifugal shell construction, and

Fig. 4 is a vertical sectional View of another form of apparatus embodying my invention.

In the illustrative embodiment of my invention shown in the drawings, a centrifugal shell or basket 10 is mounted upon end pieces 11 of spokes or arms 12 that lead to a hub 13 that is keyed to the main shaft 14. The lower end of the shaft 14 rotates in bearing 15 supported by arms 16 extending radially inward from an annular base 17 Projections 18 on the base 17 support a frame 19 to which is secured a housing 20 that carries a bearing 21 for the upper end of shaft 14.

Centrifugal shell or basket 10 is generally frusto-conical in form and its angle of divergence is such that solid material introduced to the shell at a point thereof of lesser diameter will have imparted to it, by the centrifugal force acting upon the solid material, a tendency to move relatively to the shell toward a point thereof ofgreater diameter; and the solid material is discharged from the shell atsuch point of greater diameter or at the point of maximum diameter of the shell, but the motion of the solid material toward its point of discharge is so controlled that the solid is centrifugally freed of liquid to a desired degree as hereinafter described. Shell 10 comprises a zone or portion 22 of relatively lesser average diameter and a zone or portion 23 of relatively greater average diameter. Pipe 24 or other suitable 'means feeds mixturesof liquid with solid particles into zone 22. The major portion of the liquid in the mixture is centrifugally separated from the solid particles and centrifugally discharged from the shell while the mixture is in zone 22, and the solid particles,

usually carrying some liquid are centrifugally discharged from zone 22 into zone 23, passing freely over intermediate portion 25 of the bowl in passing from the smaller zone to the larger zone of the shell. As a preferred construction the shell, in both zones 22 and 23, may consist of sheet metal having perforations 26 (see Fig.3), and an inner screen 27 having perforations 28 that are as small and as close together as desirable and a spacing member 29 intermediate the shell 10 and the screen 27, convenient material for such spaclng member being woven wire screen that will permit circulation of liquid between screen 27 and shell 10.

' from the inlet The advance of solid particles within the shell toward their point of discharge is retarded or controlled preferably by a helical plate or a series of helical plates contacting with, or as closely adjacent as practicable to,

the inner surface of the screen 27. In the construction shown in Fig. 1, a quill or hollow shaft 30 surrounds main shaft 14 and is supported. at .its upper end in bearing 31 in the housing 20 and within its lower end it is provided with a bearing 310 that ehgages shaft 14. Hub 32 keyed to the lower end of quill 30 carries arms 33 upon which are supported helical plates 34 as by joining flanges 35 on arms 33 with flanges 36 on plates 34. .[n the construction shown one helical plate begins at the lower end of each arm 33 and the helical plates slope downwardly in the direction of rotation of .shell 10 and thereby tend to cause a circulation of air within shell 10 from the point of discharge thereof toward the point where substances are supplied thereto.

The retarding or controlling helix or helices 37 within zone 22 may be supported upon a supporting and guiding plate 38 carried by arms 33, which plate comes into contact with quill 30 and provides a guide for material introduced through supply pipe 24.

The pitch of helical plates 34 may be so varied that those plates are closer together axially near the point of the shell of maximum diameter, from which'solid particles are discharged, than at parts of the shell of lesser diameter in order that the body of solid material between adjacent helical plates may have substantially the same radial thickness at points of the shell of different diameter.

Liquid discharged from the ,shell while the mixture is in zone 22 never has done upon it the work necessary to bring it up to the peripheral speed of material in zone 23.

The tendency of centrifugal force to move all of the solid material and any liquid adhering thereto relatively to the shell from the supply point to the discharge point thereof is opposed and controlled by the helical controlling or retarding plates. and the rate at which solid material advances point to the discharge point of the shell is controlled by rotating the helical plates at a differential speed with respect to the rotation of shell 10. In the construction shown the helical plates are rotated at slightly lower speed than shell 10 and the portion of a plate 34 whi'h is contacted by a given portion of material may be said to advance toward the point of discharge of shell 10. Shaft 14 of shell 10 may be driven directly from shaft 40 by belt 41, and pulley 42 on quill 30 is driven at a difierential speed by belt-operated speed-change gearing 43. The particular construction of speed-change gearing constitutes no part of my invention and any known type may be employed.

Supported upon base 17 is collecting receptacle 44 for liquids centrifugally thrown from shell 10, said receptacle comprising plate 45 which extends to a point adjacent the upper end of shell 10 and plate 46 which may extend into a trough 47 formed in the lower edge of shell 10. Liquid is withdrawn from collecting receptacle 44 by passage 48.

Solid material discharged from the lower end of shell 10 drops into hopper 49 which may conveniently be supported from the lower edge of base 17 In order to prevent steam, mist or vapors from mixtures introduced to the shell or from substances centrifugally discharged from the shell. from contaminating solid material discharged from the shell a current of air or treating gas of suitable temperature and composition is maintained from the discharged solids toward other parts of the centrifugal machine. For this purpose hopper 49 may be provided with a discharge valve 50 havinga rotating gate 51 and a supply of air or gas may be brought into hopper 49 through pine 52. Furthermore plate 53 may be carried by arms 33 and so proportioned as to close the main passage through the shell leaving a free space for air or gas to circulate between the helices 34.

In order to ensure that the layer of solid material undergoing centrifugal treatment will be of uniform thickness in spite of the large angle of divergence of shell 10. a backing plate 54 may be provided that is carried by arms 33 and spaced at suitable distance from screen 27. The helices 34 and 37 are then mounted upon backing plate or shell 54. In such a construction the flow of air or treating gas is certainly maintained in countercurrent to the solid material advancing in the shell toward its point of discharge therefrom In such case plate 53 is dis ensed with.

To prevent corrosive action of substances treated in the centrifugal machine from weakening parts thereof upon which comes the strain of centrifugal force. the shell 10 may be imperforate and provided throughout its inner surface with a layer of protective material made up of the parts 56, 59, reenforcing bands 55 being mounted. if desired. on the exterior of shell 10'. In such construction intermediate spacing member 29 will lie directly upon protective layer or sheet 56 and screen 27 will overlie and be su orted by spac ng mem er 29. Liquid passing through screen 27 will flow along the surface of protective layer 56 in the space maintained by spacing member 29. Shell 10 will be provided with liquid discharge openings 57 that are lined with protective material, a ridge 58 of protective material 56 of protective material may protect the outer surface of the shell belowliquid discharge passages 57 Liquid centrifugally discharged through screen 27 will be centrifugally discharged from the bowl through openings 57 or 57 but the inner surface of the shell may be protected below openings 57 by'protctive layer 59.

While I have described my invention in considerable detail it is to be understood that it is not limited to the details above set forth but includes such modifications and variations as fall within the hereunto appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is:

' 1. In the centrifugal treatment of mixtures of liquids and solids the process comprising subjecting the mixture to centrifugal force in a centrifugal rotor and thereby separating the mixture into its liquid and solid constitutents and centrifugally discharging the solid constituent in dispersed form, and flowing. treating gas into contact with the solid constituent, while it is in the dispersed form in which it is discharged, prior to contacting such gas with the mixture or the liquid constituent thereof. A

2. In the centrifugaltreatment of mixtures of liquids and solids the process comprising introducing the mixture into a centrifugal rotor at one end thereof and centrifugally separating and discharging the liquid constituent, advancing the solid constituent toward and centrifugally discharging it from the opposite end of the rotor, and maintaining a flow of treating gas through the dischargingsolid constituent and within the rotor countercurrent to the direction of advance of the solid constituent therein.

3. In a centrifugal machine, a centrifugal rotor mounted for rotation, means for introducing into one end of said rotor mixtures of solids with liquids, a helix within said rotor and positioned to engage solid material un der the influence of centrifugal force therein and having a downward pitch in the direction of rotation of the rotor, means substantially closing-the central portion of said helix against the flow of gas, a hopper normally closed at its bottom and positioned to receive solids discharged from said rotor and having its upper edge adjacent said rotor, and

Y 5. In a centrifugal machine, a rotating centrifugal rotor discharging solids from one end thereof, means for introducing into the other end of said rotor mixtures of solids and liquids and means for passing treating'gas through said rotorfrom the discharge end thereof toward the other end thereof.

6. In a centrifugal machine,a frusto-conical centrifugal rotor mounted for rotation, means for introducing a mixture of liquid with solid particles into the end of said rotor of smaller diameter, a centrally open helix positioned to engage solid particles under the influence of centrifugal force within said rotor and mounted for rotation with respect to said rotor, means for closing the central opening of said helix, and means for circulating gas through the space between said closure means and said bowl and from the larger end of said rotor toward the smaller end thereof.

7. In a centrifugal machine, a frusto-conical centrifugal rotor mounted for rotation, means for introducing a mixture of liquid With solid particles into the end of said rotor of smaller diameter, an imperforate backing shell within said rotor and mounted for coaxial rotation relative thereto and s 'aced therefrom, a helix on said backing she I and engaging solids under the influenceof centrifugal force within said rotor, and means.

for passing gas between said rotor and shell and from the larger end of said rotor toward the smaller end thereof.

8. Ina centrifugal machine, a frusto-conical centrifugal rotor mounted for rotation. and havlng a corroslon reslst ng lining, a

spacing member covering the interior'of said rotor and permittingcirculatwn ofliquld over said lining, a perforate screen covering said,

spacing member, a liquid restraining wall extending inwardly from the inner surface of said rotor at a point thereof of larger diameter, said rotor having liquid discharge open ings adjacent said wall on that side of said wall toward a point of said rotor of lesser diameter and said rotor being open at its ends and otherwise closed, and means for introducing mixtures of liquids and solids into the smaller end of said rotor.

In testimony whereof, I have signed my name to this specification.

LAURENCE P. SHARPLES'.

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