US2292990A

US2292990A - Centrifugal separator

Info

Publication number: US2292990A
Application number: US285667A
Authority: US
Inventors: Henri G Chatain
Original assignee: Individual
Current assignee: Individual
Priority date: 1939-07-21
Filing date: 1939-07-21
Publication date: 1942-08-11
Anticipated expiration: 1959-08-11

Description

H. G. cHATAlN l 2,292,950

CENTRIF'UGAL SEPARATOR Filed July 2l, 1939 5 Sheets-Sheet 2 I Aug; 11, 1942. H. G. CHATAIN 2,292,990A

CENTRIFGAL SEPARATOR Filed July 2l, 1939 5 Sheets-Sheet 5 @L g @2% EY Aug. ll, 1942. H. G. cHATAlN CENTRIFUGAL sE'PARAToR Filed'July 21, 1959 5 sheets-sheet 4 ATT RNEY.

A118- 11, 1942 H. G. cHA'rA'lN 2,292,990

' CENTRIFUGAL sEPARAToR Filed July 21, 1939 v 5 Sheets-Sheet 5 i l l MATT RNr-:Y

Patente-d Aug. 11, 1942 AUNITED STATES PATENT OFFICE CENTRIFUGAL SEPARATOR Henri G. Chatain, Erie, Pa.

Application July 21, 1939; Serial No. 285,667

Claims.

The invention relates to method and means for filtering or extracting liquids from solids. More particularly it relates to improvements in centrifugal separators of the'continuous type as distinguished from those designed for batch operation.

Centrifugal separators of the continuous type generally provide for continuousfeeding ofthe stock at a controlled rate and for continuous discharge ofthe separated liquid fraction or fractions. Discharge of the solid fractions may be either continuous or intermittent. Attempts to provide for continuous discharge ofY the solid fraction have beenl attended with serious difficulties, particularly as applied to the treatment of brous materials or other materials yielding a solid fraction which does not flow readily. Movement of the solid fraction toward the point of discharge has been accomplished, or proposed to be accomplished, in many different ways. For example, it has been-proposed to use helical-con- Veyors; Scrapers which exert a raking action on the material; ldisc harrows; or pistons which push the materiall toward the point of discharge. While suchl devices may have merit as applied to the separation of liquids from certain classes ofrnaterial, they are not well adapted to the treatment of materials of a `fibrouscharacter such `aspaper pulp, fibrous cellulose, acetate, and nitrate, certain sludges from sewage and other materials in the sugar, rubber and fibrous board industries. The solid fraction of such materialsV tends to clog a helical conveyor; and rakes or Scrapers which intermittently lift away from the surface of a centrifugal filter basket do not readily get down through the material on succeeding bites as the density of the solids increases during centrifuging. Again, p-istons which push thematerial toward the point of discharge tend to distort the cake of solids, leading to lack of uniformity in extraction and adversely affecting the length of time required to achieve a given percentage of reduction in moisture content. With such a method the cake does not maintain a uniform thickness, but will frequently hump up, thereby increasing the difficulty of extracting the liquor. It is an object of my invention to provide a method and means for continuous centrifugal separation of solid and liquid fractions which overcomes these and other difficulties, and which is particularly advantageous in the centrifuging of fibrous materials.

A general object kof the present inventionis to provide means for continuously extracting liquids from moist solids more rapidly and efficiently than is possible with methods and apparatus heretofore known.

A specific object of my inventionis to provide an improved method and means for causing solids to traverse the length of a centrifugal lter basket Without clogging -or humping.

A further specific object is to provide improved auxiliary pressure extracting means to supplement centrifugal extraction. .Y A further object is to provide an improved form of filter basket. Other objects and advantages of my invention will appear as the description proceeds. i

As previously noted, one of the principal difficulties experienced in the centrifuging of fibrous materials, and materials possessing similarcaking characteristics, resides in the problem of obtaining a uniform discharge of the cake without clogging or humping. Factors influencing removal of the cake in undistorted form are: (l) the density of the cake; (2) the width of the cake in advance of the pushing element; (3) the thickness of the cake; (4) the coefficient of friction betweenv the cake and the surface of the filter basket; and (5) the centrifugal force developed by the machine. I have found thatfor a given material, centrifugal force and cake thickness, improved handling of the cake can be obtained by running ejector blades circumferentially into the cake at an acute angle to a plane normal to the axis of rotation of the filter basket, and intermittently advancing the ejector blades toward the discharge end of the basket, so that, in effect, the ejector is screwedinto the cake from the discharge encl and pulls the cake out like an annular cork. In order to havecontinuous operation this must take Iplace while the basket and ejector are rotating. The screwingin.action is accomplished by having the ejector screw and basket rotate at somewhat different speeds. It is quite essential, in accordance With my 5preferred method, that the ejector screw enter the cake or advance its position into the cake, substantially without moving the cake axiallyY of 'the filter basket. In this way very little resistance is offered to the action of the ejector even with a fibrous cake, or a cake of great density. Axial movement of the cake is performed intermittently by bodily movement-of the ejector screw and not by a helical conveyor action.

In 'order that the nature and many advantages of my invention Will'be fully understood, I shall describe certain preferred embodiments thereof` with reference to the accompanying drawings, in which Fig. 1` is a vertical longitudinal sectional view of a centrifugal separator capable of operation-in accordance with my novel method, and embodying novel features of construction to bev described.

Fig'. 2 is a transverse sectional View taken on the line 2 2 of Fig. 1.

Fig. 3 is a detail View of the cam mechanism for intermittently advancing the ejector blades toward the discharge end of the basket; and-Fig. 4 is a transverse sectional View on the line 4-4 of Fig. 3.

tail sectional view on the line III-I of Fig. 9.V

Figs. ll to 13 illustrate another embodiment Vof,

the invention in which the axis of the separator is vertical instead of horizontal; Fig. 11 being a central vertical sectional View; Fig. 12 a detail vertical sectional view showing the liquid discharge outlets; and Fig. 13 a sectionalview on the line I3-I3 of Fig. ll.

The apparatus comprises, in its general arrangement, a casing I, within which are rotatably mounted a chamber or basket 2 and a helical ejector 3. The casing I is provided with an intake conduit, or alimentary pipe, 4, arranged to charge the separator with a slurry to be filtered, and is also provided with an outlet, or series of outlets, 5, for discharge of the liquid fractions, and an outlet 6 for discharge of the solids. The basket element 2 and ejector element 3 are mounted in association with a main shaft 1 and auxiliary shafts to be described, driven by a differential mechanism which causes one of said elements to rotate at a slightly higher speed than the other. Means are also provided to produce intermittent movement of one of said elements with respect to the other in an axial direction, i. e., parallel to the axis of the shaft 1.

As another element of the general combination there may also be provided a discharge ring 8 driven by a planetary transmission from the shaft 1.

The shafts for the rotating

elements

2, 3, and 8 are supported on bearings 9 and I8, the supporting rings of which may have spherical surfaces for engagement with similar surfaces in the housings II and I2, respectively. These housings are carried on a suitable supporting frame, or base, I3. Keyed to one end of the shaft I is a pulley I4 driven from a suitable source of power. The basket 2 is supported on a pair of quill shafts I5, I6 surrounding the main shaft I and driven therefrom. The quill shaft I5 is driven from the main shaft 'I through suitable gearing. For this purpose I have shown gears I'I and I8 keyed respectively to the shafts 'I and I5, gear I'I meshing with a pinion I3 keyed to a shaft 20 conveniently carried in the housing 2l which surrounds the gearing. Also keyed to the shaft 28 is a pinion 22 which meshes with gear I8 previously referred to. In the embodiment illustrated the basket 2 is arranged to rotate at a speed which is somewhat greater than that of the helical ejector. This differential speed is produced by the transmission gearing just described. The purpose of the speed differential will be explained later.

l Since the quill shaft I3 forms a part of the basket 2, it will be understood that the transmission gearing in the housing 2l serves to drive the shaft I6 as well as the shaft I5. The discharge ring 8 is driven through the shafts 'I and I6. The ring 8 is mounted on spokes 23 radiating from a hub 24 having a bearing portion 25 to receive a portion of the quill shaft I6 about which the ring is arranged to rotate. To drive the ring 8, gears 26 and 21 are keyed, respectively, to the shafts I6 and 1, and these gears mesh with planetary gears 28 mounted on stub shafts 29 secured to the ange 38 of the hub 24.

There are three sets of these planetary gears 28 as shown in Fig. 2. Inasmuch as the speed differential between the shafts 'I and I6, and therefore between the

gears

28 and 21, is not great, the planetary gearing described causes the ring 8 to rotate much more slowly than the basket 2. Cooperating with the discharge ring 8 is a scraper 3| (Figs. 1 and 2), mounted on the ange 32 secured to the housing I. The angular arrange-- ment of the scraper 3l is such that the material collected on the discharge ring 8 is scraped o into the discharge outlet 6.

The helical ejector 3 is carried by a quill shaft 33, mounted on the main shaft 'I and keyed toit by a spline 34 in such a manner las to be slidable longitudinally of the shaft 1. Longitudinal movement of the ejector is positively controlled, as by cam action, at least during that portion of its cycle when it is moving to the right as viewed in Fig. l. For this purpose I prefer to employ a cam or cams associated with one or both of the quill shafts I5 and 33. In the embodiment illustrated I have provided a pair of

cams

34 and 35 secured, respectively, to the adjacent ends of the shafts I5 and 33, and cooperating cam rollers 36, of which there may conveniently be two, mounted on stub shafts for rotation in a ring 31 which, in turn, is rotatable with respect to the shaft 'I on which it has a bearing. One of the cams may have a plane surface, or both may be undulating or be provided with humps for controlling longitudinal movement of the quill shaft 33. As illustrated, the cam 35 has a plane surface serving as a race for the rollers 36, while cam 34 has a surface which, as developed, would appear substantially as shown in Fig. 5, having a pair of humps 33 located apart to correspond with the spacing of the two rollers 36. The rollers 36 may be mounted on ball or roller bearings as indicated in Fig. 3. If desired, however, the rollers 38 can be omitted from the construction shown, and the two cams designed for direct engagement with one another. The form of the humps 38 is important in achieving certain of the objects of my invention, and will be described more particularly hereinbelow. If desired, a helical spring 39 may be provided between the end of the shaft 33 and a collar or flange 4I] on the shaft 'I to insure that the ejector 2 will be correctly positioned when the apparatus is put into operation; also to assist in the screwing-in action to be described. 'Ielescoping sleeves 4I and 42, attached, respectively, to shaft 33 and collar 40, provide a housing for the spring 39.

The preferred construction of the basket 2 will now -be described with reference principally to Figures 1, 2, 9 and l0. The frame of the basket may conveniently be in the form of a casting of open cylindrical form having spaced circumferential rings 43 joined together by longitudinal members 44. The ring members 43 are provided with a series of longitudinally extending slots 45 (Fig. 10) to receive the wedge-shaped longitudinal bars 43 which form the inner surface of the basket. These bars 46 are so designed and spaced that their inner edges are spaced apart a suitable distance to permit escape of the liquid fraction of the material which is to be centrifuged. For paper pulp, fibrous cellulose, acetate and nitrate, certain sludges from sewage and other materials in the sugar, rubber, and fibrous board industries, I have found that spacings of v0.004 to 0.010 of an inch give good results. This refers to the spacing between adjacent bars at the point where they come closest together, as shown at 41 in Fig. 10. It will be understood that the spacing of vthe bars depends upon the nature of the materials to be separated and may be varied in accordance with this factor.` In my preferred construction the inneredges 48 of the bars which are to form the inner surface of the basket arearcuate in cross section. I have found that this form of edge assists the liquid to find its way to the slots `41under the action of centrifugal force. The bars 46 may be held in place in any convenient manner, and in my preferred construction the ends of these bars are slotted as at 49 to receive the peripheral flange 59 Aof a clamping ring `5| which is secured to a ange 52 formed on the end ring 43 of the basket frame by means of studs 53 and nuts 54 provided at intervals around the periphery of the frame. This construction is shown best in Fig. 9. At one end o f the basket 2 the clamping ring 5I is secured to the rim 55 of the wheel which has the quill shaft |46 for a hub, and to which it is connected by radial spokes 56. The wheel thus formed may be strengthened by the provision of circumferential tubular elements 51 which may conveniently pass'through suitable apertures in the spokes 56. An end plate 58 is secured to the clamping ring I at the other end of the basket, and this end plate forms the rim of a wheel of which the quill shaft I5 constitutes la hub, the plate 58 and shaft l5 "being connected by a plurality of,l radial spokes 59. The end plate 58 is provided with a flange 60 which may be in the form of a truncated cone, and which cooperates with a flange 6I secured to the end of the casing l to insure that the material charged into the separator will be directed to the interior of the basket and not nd its way between the end plate 53 of the basket and the wall of the casing l.

The alimentary pipe 4, through which the material is charged into the apparatus, preferably is of the form shown in Fig. 7, having two branches 62 which extend in aV generally circumferential direction from their point of connection with the pipe 4 so as to avoid interference with the spokes 59. The extremities of the branches 62 may be turned outwardly in a radial direction to direct the material toward the periphery of the rotating basket and ejector.

The construction of the ejector 3 will now be described principally with reference to Figs. 1 and 6. The quill shaft 33 forms the hub of the ejector wheel. Radial arms or spokes 63 extend outwardly from the shaft 33, six double spokes being shown in the embodiment selected for the purpose of illustration. The ends of the double spokes 33 are joined by a radial plate 64, the outer edge of which is inclined, as shown in Fig. l. The plates 64 are cut to form a thread which receives the innerhedges of a helical element 65 formed of a flatv strip the width of which decreases in the direction of flow of material through the separator,A i. e., from left to right as viewed in Fig. 1. The outer edges of the helical ejector thus formed lie approximately in the plane of a right circular cylinder. The inner edges of the helical element of the ejector lie approximately in the plane of a truncated cone. The reason for adopting this particular construction resides in the fact that the layer of material p-assing through the separator will be thicker at the ventering side offthe machine where its liquid content is greater, and progressively thinner as the cake approaches the discharge end of the machine, becoming more and more compressed and cie-liquefied. The outer diameter of the ejector 3 is slightly smaller than the inner diameter of the basket 2.

In some instances it may be desirable to separate the liquids into selected fractions, in which event the casing I may be provided with a plurality of partitions 65 arranged circumferentially of the basket 2 and opposite intermediate circumferential rings 43 thereof, so as to effect a separation of the liquid which passes through the openings between successive rings 43. The partitions 66 thus cooperate with the separate discharge openings 5 previously described in separating the filtrate fractions. t

It may be found desirable to apply pressure mechanically to the cake as it emerges at the discharge end of the ejector in order to obtain more complete extraction of liquid from certain materials which are so formed or of such a character as to require such auxiliary pressing. For this condition, it may be desirable to provide pressure rolls designed to squeeze the cake directly against the inside of the basket. In the embodiment illustrated, I have shown apparatus for this purpose, which apparatus will now be described principally with reference to Figs. 1 6 and 8. This apparatus consists essentially of one or more pressure rolls 61 which are pivotally and resiliently connected to the quill shaft 33. For this purpose, shaft 33 has formed thereon or secured thereto, lugs 68 (Fig. 8). In the embodiment illustrated, these lugs are formed integrally with the shaft 331. Pivotally secured to each lug 68 by a pin 59 is a bifurcated link 10 designed to pivotally receive the pressure roll 61 between the furcations thereof. The furcations of the link 10 are connected near their point of attachment to the lug 68 by a bridging element 1I having a surface 12 for engagement with the lug 68 to limit the movement of the link 1i] about the pivot pin 69 in a counterclockwise direction as viewed in Fig. 8. In this limiting position it is preferable that there shall be a slight clearance between the roll 61 and the inner surface of the basket 2. The pressure roll is resiliently urged into this limiting position by means of a compression spring 13 which bears at one end against one of the lugs 68 of the quill shaft 33 and at its other end against a spring seat 14 which is pivotally connected to the link 10 by means of a pin 15. The spring 13 is further positioned and guided by a rod 18, one end of which is secured to the spring seat 14 and the other end of which projects through an aperture 11 which extends through the lug 68 and pin 69. In order to provide for angling of the rod 16 when the link 10 swings in a clockwise direction about the pivot 69 as indicated by the arrow a in Fig. 8, the aperture 11 is flared outwardly at each end as indicated at 18, 18. The rod 16 serves to hold the pin 69 against longitudinal movement, while the pin provides an angularly movable guide for the rod. The furcations of the link 10 may be extended angularly beyond the bearing for the pressure roll 61, as at 19, to provide a support for a knife 80, providing a scraper to keep the surface of the roll free from accumulations. It will be understood that as the pressure rolls B1 swing around the main shaft 1 in the direction indicated by the arrow b (Fig. 8) they may also swing about the pivots 69 against the action of centrifugal force, and of the spring 1.3, to provide greater or less clearance between the rolls and the basket as the thickness or compressibility of the material discharged from the ejector 3 Varies. The rolls are constantly urged outwardly toward the limiting position shown in Figs. 6 and 8 by centrifugal force augmented by the action of the springs 13. I'he principal function of the springs 13 is to hold the rolls 61 in their outermost position as the machine is being put into operation.

If desired, means may be provided for introducing liquids into the interior of the basket for washing or impregnating the material during the process of centrifuging, or for such other purpose as may be contemplated. To this end I have made the shaft 1 of hollow form and provided it with a series of discharge openings 8l and 82. The ends of the shaft 'l are closed by

plugs

83 and 84, the latter of which is apertured to receive an inlet pipe 85 for the liquid to be introduced. In the particular embodiment illustrated I have provided for the introductionof liquids from two sources and have shown a dam 86 dividing the hollow interior of the shaft into two compartments. Liquid from the pipe 85 enters the one compartment, and a pipe 8l extends through the interior of the pipe 85 and through an aperture in the dam 86 to discharge liquid into the other compartment. A second dam 88 may be placed around the inner end of the pipe 85 to confine the liquid in the rst chamber. The quill shaft 33, which has been previously described, is longitudinally movable with respect to the shaft 'l which must be provided with

elongated apertures

89 and 90. The

apertures

8l, 82, 89 and 90 may be arranged at several points around the periphery of the shafts 'l and 33 as shown in Fig. 8. In order to distribute the liquid uniformly over the contents of the basket, there may be as many series of outlets as desired, and these may be so arranged that the liquids will drain principally between selected partitions 43 of the basket and thence be discharged between partitions 66 and through selected outlets 5.

As previously mentioned, the drive for the basket and ejector elements is such that one of them rotates at a somewhat greater speed than the other. The actual speeds depend upon the character of the material which is to be processed, and upon other factors which have been mentioned. However, in describing the operation of the machine it will be convenient to assume that for a given material, the Abasket 2 is arranged to rotate at 350 R. P. M. and the ejector 3 at 300 R. P. M. Assuming further that the direction of rotation of the basket and ejector is clockwise as viewed in Fig. 6, the helical element 65 of the ejector will be in the form of a lefthand screw. Proceeding with these -assumptions, I shall now describe the method of operation of the preferred embodiment of my apparatus illustrated in Figs. 1 to 10 of the drawings as follows:

The material to be de-watered is introduced continuously and at a suitable consistency through the alimentary pipe 4 from which it is discharged into the interior of the machine through the branch pipes 82. It has been explained that the ejector 3 is longitudinally movable along the main shaft l and with respect to the basket 2. As the separator is put into operation, the ejector will b-e at the limit of its movement to the left, as viewed in Fig. 1, under the action of the coil spring 39, the relative position of the

cams

34 and 35 being as indicated in Figs. 3 and 5, in which the cam rollers 3'6 are in the troughs of the cam 34, permitting the cams to assume that position in which they are closest together. The

cams

34 and 35 move the ejector 3 to the right against the action of the spring 39 a distance which is equal to the height of the humps 38 of the cam 34. In the embodiment illustrated, this distance is on the order of 1 inch and this dimension will be assumed in further discussion of the operation. This movement of the ejector to the right occurs-say-50 times per minute, which will give a discharge of material equivalent to a cylinder 50 inches long having an outside diameter equal to the inside diameter of the basket 2 and an inside diameter which will depend upon the thickness of the cake at the discharge end of the helical element 65.

With the basket 2 rotating in a clockwise direction at 350 R. P. M. and the ejector 3 rotating in the same direction of 300 R. P. M., the ejector is in effect rotating counterclockwise relative to the basket at a speed of 50 R. P. M. This means that the lefthand helical element 65 of the ejector screws into the material in the basket, moving from right to left as viewed in Fig. 1. The material entering the separator is thrown to the periphery of the basket by centrifugal force, where it forms a cake the thickness of which decreases progressively as the cake approaches the discharge end. of the machine, becoming more and more compressed and de-liqueed. This condition is shown in Fig. l. The pitch of the helical element is such that it screws into the cake at a speed which brings it to its limit of travel to the left just at the point where the hump 38 of the cam 34 is ready to move the ejector bodily to the right. The longitudinally inclined portions of the cam 34 which lie beyond the humps 38 preferably are at such an angle as to permit the ejector to move to the left at exactly the speed produced by its action in screwing into the cake. Thus there will be substantially no movement of the cake with respect to the basket during the screwing-in action. In other words, the helical ejector does not act like a helical conveyor, but rather like a corkscrew which screws into the annular cake and is intermittently pulled toward the discharge opening to produce bodily movement of the cake in that direction.

If desired, the movement of the ejector to the left may be controlled entirely by the screwingin action, independently of the cam. This might be accomplished, for example, by designing the Vcam 34 with a steep slope on both sides of the humps 38, in which case there would actually be a clearance between one of the cams and the rollers during the screwing-in action, and the spring 39 would be so designed as to be insufciently strong to move the ejector to the left to take up this clearance (and yet sufficiently strong to take up this clearance at the beginning of operation when there is no cake in the basket). I prefer, however, to design the cam 34 in the manner first indicated so as to insure that the ejector will move to the left at a speed which is no greater than that produced by the screwingin action, in which case the spring 39 can also be made suciently strong to insure that there will be no helical conveying action tending to produce bodily movement of the cake to the right during screwing-in action.

From the foregoing description of the operation of my apparatus, it will be understood that the helical ejector screws into the material a short distance to the left without exerting any helical conveying action thereon, and is intermittently pushed to the right by the cam action a distance equal to the travel of the ejector during the screwing-in action. Therefore, considering the 1 inch travel of the ejector as postulated, it Will be seenthat the action of the ejector is to shift all of the material in the basket toward the discharge end, ejecting a cake of material in the form of a hollow cylinder 1 inch in length. Based on the assumptions previously made as to relative speeds of the basket and ejector, the action described occurs 50 times per minute and ejects 50 inches of material per minute. As each increment is discharged, it is thrown centrifugally to the discharge ring 8 from which it is removed by the scraper 3| which directs the material into the discharge opening 6. The liquid fractions are drawn off through the discharge ports 5, along with such wash water or impregnating liquid as may be introduced through the pipes 85 and Bl.

It will be understood that the basket and ejec tor could be designed for counterclockwise rotation insteadV of clockwise rotation, in which case the helical ejector element 65 would be in the form of a right-hand screw instead of a lefthand screw as shown. Also, it would be possible to have the ejector rotate at a higher speed than the basket,remembering` that the direction and pitch of the thread of the helical ejector must be such as to create the proper screwing-in action, as determined by the direction and magnitude of the speed differential.

Figs. 11-l3` illustrate another embodiment of the invention as applied to a vertical separator. The casing 9| of this separator is vprovided at its lower end with brackets 92 disposed at convenient points around its periphery. The entire unit is supported from pedestals 93 by means of self-centering supports 94 which, as shown, consist of rods engaging rubber blocks 95 associated with the pedestals 9,3 and with the brackets 92, The bottom 96 of the casing 9| is provided with an opening to receive a bearing support 9'! which, together with the housing 98 secured thereto, supports the shafts of the rotating elements of the machine and forms a housing for the gears and cams to be described. The shafts for said rotating elements are carried by

bearings

99, 99 and |00. I iind it convenient to employ `tapered roller bearings at 99, 99A and a ball bearing at |00. The quill shaft of the basket |02 is carried directly in the bearings 99, 9 9- I'he quill shaft |09 which drives the helical ejector |04 is rotatably and slidably carried within the quill shaft |0|. Ihe main shaft |05 is keyed to the quill shaft |09 at |00, and drives the quill shaft, |03 through this key, while permitting the quill shaft to slide with respect thereto under the influence of the cam action and screwing-in action to be described.

The construction of the basket |02 and helical ejector |04 is substantially the same as has been described in connection with the embodiment illustrated in Figs. 1-11, so it is considered unnecessary to describe this construction in detail. The basket has a perforate surface formed by a series of parallel bars clamped together inthe manner previously described. It is mounted on the spokes |0'| attached to a hub |08 secured to the quill shaftv |0|. At its` top it is provided with a plate or shield |09 which corresponds in its general function to the plate 58 of the hori- Zontal separator previously described.

The material which is to be processed is introducedthrough the pipe Y| l0 from which it is directed against a rotating guide plate securedto the main s haft |05. The periphery of the guide plate preferably is flanged up wardly as at 2 to guide the entering material toward the top o f the helical ejector |04.

The main shaft is driven from any suitable source of power and for this purpose I have shown a motor ||3 mounted on a bracket ||4 bolted to the bottom 96 of the casing. 'Ihis motor is'connected by suitable belting to a pulley life secured to the main shaft |05. Also secured to the main shaft is a gear ||9 which meshes with pinions ||l keyed to shafts H8, ilil, to the other ends of which are secured pinions H9, H9. The shafts H3, ||8 are conveniently carried in the

housing member

91, 98. The pinions H9 mesh with a gear |20 keyed to the quill shaft |0|. 'I he gear ratio between the gears and pinions H6, ||1 is slightly different than the gear ratio between the pinions ||9 and gear |20 so that the quill shaft |0| is driven from the main shaft |05 at a somewhat different speed than shaft |05. The construction which I have shown is designed to produce a higher speed of rotation of the basket than o-f the ejector, the basket and ejector being driven respectively at the speeds of the quill shaft |0| and main shaft |05. For example, the basket may be geared for rotation at 1000 R. P. M. and the ejector at o `R. P. M.

In this embodiment of the invention the rela` tive bodily movement between the basket and ejector is controlled by the` cams |2| and |22, in cooperation with rollers |23 carried by a collar |24 rotatably mounted on the quill shaft |03. The construction and operation of these cams and rollers may be the saine as has been de-` scribed with reference to the cams34 and 35 and rollers 36 of the horizontal machine.` The cam |2| is keyed to the gear shaft |0| and the cam |22 is keyed to the quill shaft`|03 so as to produce relative" longitudinal movement be'- tween these two quill shafts. Since the ejector |04 is mounted on the quill shaft |03, and the basket on the quill Shaft |0l, Athese cams provide for intermittent longitudinal movementof the ejector with respect to the basket. As in the embodiment previously described, the Inovement of the ejector toward the discharge end of the basket (i.Y el, the lower end o f this embodi# ment) is relatively rapid, whereas the return movement of the ejector is synchronized with the screwing-in action so as not to produce relative movement of the cake and basket during the return travel ofthe ejector. In other words, the ejector does notact as a spiral conveyor but merely screws Vinto the material in the basket and pulls it downwardly at intervals by bodily longitudinal movement. A coil spring |25 is arranged withiir the main shaft |05 so as to bear at one end against the end of the hollow portion of the shaft andat the other end against the key |06 to urge the quill` shaft liitandV thereffore the ejector |04 Vupwardly Y toward its starting position,`and to take up all clearance between the cams |21, |22 and rollers |23. This makes it possible to so design the cams as to positively control the s'upeed of return of the ejector so as to synchronize it with the screwing-in action and avoid any tendencyY of the ejector to act as a helical conveyor. The shafts Il may be three in number as shown in Fig. 13, each carrying Va pair of gears `||'9. Y,

Mounted for rotation with the helical ejector |04 are two series of pipes |26 for distributing liquid to the cake in the basket 02. These pipes conveniently are attached to the hub |21 of the ejector, which hub in turn is secured to the shaft |03. Apertures |28 and |29, formed respectively in the shafts |03 and |05, provide communication between the interior of the pipes |26 and the interior of the shaft |05, Apertures |29 are elongated in order to provide for relative movement between the shafts |03 and |05 without closing olf communication between the pipe |26 and interior of the shaft |05. Suitable liquids for flushing or impregnating the cake may be introduced in a manner similar to that which has been described in the embodiment of Figs. 1-11 inclusive. For this purpose, I have provided a series of dams |30 at spaced intervals along the interior of the shaft in order to divide'it into separate compartments. Concentric feed pipes |3| and |32 communicate respectively with the chambers |33 and |34 thus formed, so that liquids can be introduced while the machine is in operation. Liquid from the upper set of pipes |26, together with a liquid fraction separated from the material being treated, passes through the basket |02 as indicated by the arrows c into the chamber |35 formed between the casing 9| and a cylindrical wall |36 which is concentric therewith and is spaced therefrom. The wall |36 may be provided with a flange |31 at its upper end to assist in separating the liquid fractions. Liquid discharged from the lower set of pipes |26, together with a liquid fraction extracted from the material, passes through the basket 02 in the direction indicated by the arrows d into the chamber |38 formed between the cylindrical wall |36 and a second cylindrical wall |39 spaced therefrom and concentric therewith. The wall |39 may be provided with a flange |40 at its upper end to assist in guiding the discharged liquid fraction into the chamber |38. The liquid fractions are discharged from the chambers |35 and |38 through ports |4| and |42 respectively (Fig. 12). These ports may be provided with flanges, as shown, for connection to suitable pipe lines leading to vats or storage tanks as may be desired. If the basket |02 is rotating at 1000 R. P. M.- and the ejector |04 at 950l R. P. M. this means that there will be a speed differential of 50 R. P. M. between the cake, which is movingl at the same speed as the basket, and the pipes |26, which are moving at the same speed as the ejector. Ihis differential of 50 R. P. M. gives a satisfactory speed for laying the liquids upon the cake. The arrangement shown is subject to modification in accordance with the nature of the separation to be effected and the liquids to be discharged from the pipes |26.

To assist the ejector |04 in the proper discharge of the solid fraction, the ends of the spokes |01 adjoining the cylindrical 'walls of the basket |02 are connected by a conical flange |43 which directs the solids, under the action of centrifugal force, against a discharge ring |44 which may be mounted in any convenient man.- ner and arranged for rotation at a speed which is relatively low with respect to that of the basket |02. For this purpose I have provided the ring |44 with a supporting flange |45 to the under side of which is secured a ring gear |45 meshing with a series of pinions |41 carried on studs secured to the wall |39. One of the pinions |41 is keyed to a drive shaft |48 to which is secured a worm gear |49 driven from a worm |50 secured to the shaft of the motor r| I3.

The discharge ring |44 may be supported and driven in any other manner which may be desired. For example, it would be possible to support the ring on friction Wheels or discs instead of on. the pinions |41. The solids discharged from the basket cling to the walls of the discharge ring |44 under the action of centrifugal force until' they are removed therefrom by the action of a scraper |5| secured to the bottom 96 of the casing 9| adjacent the discharge outlet |52. The scraper |5| may be secured in place by means of a bracket |53 or it may be welded directly to the bottom of the casing. In the event that the material discharged from the basket is of such a character as to stick to the ring |44, auxiliary means may be provided for scraping the bottom 96 of the casing, such as radial planes or spokes extending inwardly from the ring.

It will be understood that the principle of operation of the vertical embodiment illustrated in Figs. 11, 12, and 13 is the same as has been described with reference to the horizontal type. With the speeds as previously assumed, the cams |2| and |22 are pushed apart approximately 50 times per minute. As in the case of the horizontal type, the direction of rotation of the basket and ejector may be either clockwise or counterclockwise (looking into the machine from the discharge end). If clockwise, the helical element of the ejector will be in the form of a lefthand screw; if counterclockwise, a right-hand screw. Also, the ejector may be geared to run faster, instead of slower, than the basket, always remembering that the pitch and direction of the screw should be so related to the magnitude and direction of the speed differential, and design of the cams, as to produce a screwing-in action which avoids any substantial displacement of the cake with respect to the basket except during the intermittent bodily longitudinal movement of the ejector. Other modifications will suggest themselves to those skilled in the art. The terms and expressions which I have employed are used as terms of description and not of limitation, and I have no intention of excluding such equivalents of the invention set forth, or of portions thereof, as fall within the purview of the claims.

I claim:

1. The method of separating the liquid and solid fractions of a material which comprises feeding the material continuously into a substantially cylindrical chamber having perforated side walls and an end open for the discharge of material, rotating the chamber to drive out liquid fractions by centrifugal force, and periodically ejecting a portion of the solid fraction by screwing a helical element into the material without substantial displacement of the material and intermittently moving said element longitudinally of the chamber to advance the material bodily toward the discharge end of the chamber.

2. The method of separating the liquid and solid fractions of a material which comprises feeding the material continuously into a substantially cylindrical chamber having perforated side Walls and an end open for the discharge of material, rotating the chamber to drive out liquid fractions by centrifugal force, and periodically ejecting a portion of the solid fraction by screwing a helical element into the material at a controlled rate of longitudinal movement such that for each revolution of the element relative to the chamber said element moves a longitudinal distance substantially equal to the pitch of the helix7 and intermittently moving said element longitudinally of the chamber to advance the material toward the discharge end of the chamber.

3. The method of separating the liquid and solid fractions of a material which comprises feeding the material continuously into a substantially cylindrical chamber having perforated side Walls and an end open for the discharge of material, rotating the chamber to drive out liquid fractions by centrifugalforce, and periodically ejecting a portion of the solid fraction by screwing a helical element into the material and intermittently moving said element bodily longitudinally of the chamber to advance the material toward the discharge end of the chamber, and controlling the rate of longitudinal travel of the element during both the screwing and bodily movements.

4. The method of separating the liquid and solid fractions of a material which comprises feeding the material continuously into a substantially cylindrical chamber having perforated side Walls and an end open for the discharge of material, rotating the chamber to drive out liquid fractions by centrifugal force, and periodically ejecting a portion of the solid fraction by screwing a helical element into the material and intermittently moving said element bodily longitudinally of the chamber to advance the material toward the discharge end of the chamber, and controlling the rate of longitudinal travel of the element during both the screwing and bodily movements so that said rate will be substantially greater during the bodily movement than during the screwing movement.

5. The method of separating the liquid and solid fractions of a material which comprises feeding the material continuously into a substantially cylindrical chamber having perforated side walls and an end open for the discharge of material, rotating the chamber to drive out liquid fractions by centrifugal force, and periodically electing a portion of the solid fraction by screwing a helical element into the material and intermittently moving said element bodily longitudinally of the chamber to advance the material tov/ard the discharge end of the chamber, and controlling the rate of longitudinal travel of the element during both the screwing and bodily movements so that said rate will be synchronized with the pitch of the helix during the screwing movement.

6. The method of separating the liquid and solid fractions of a material which comprises feeding the material continuously into a substantially cylindrical chamber having perforated side Walls and an end open for the discharge of material, rotating the chamber to drive out liquid fractions by centrifugal force, and periodically ejecting a portion of the solid fraction by screwing a helical element into the material and intermittently moving said element bodily longitudinally of the chamber to advance the material toward the discharge end of the chamber, and controlling the rate of longitudinal travel of the element during both the screwing and bodily movements so that said rate will be synchronized with the pitch of the helix during the screwing movement and will be much more rapid during the bodily movement.

'7. Apparatus for separating the liquid and solid fractions of a material which comprises a substantially cylindrical chamber having perforated side Walls and an end open for the discharge of material, means for feeding the material continuously into the chamber, a substantially cylindrical helical element disposed within the chamber and extending longitudinally thereof, said element comprising a helical portion extending at least for one turn about the longitudinal axis thereof, means for rotating the chamber to drive out liquid fractions by centrifugal force, and means for screwing the helical element into the material in the chamber Without substantial displacement of the material and for intermittently moving the helical element longitudinally vof the chamber to advance the material bodily toward the discharge end of the chamber.

8. Apparatus for separating the liquid and solid fractions of a material which comprises a substantially cylindrical chamber having perforated` side Walls and an end open for the discharge of material, means for feeding the material continuously into the chamber, a substantially cylindrical helical element disposed within the chamber and extending longitudinally thereof, said element comprising a helical portion extending vat least for one turn about the longitudinal axis thereof, means for rotating the chamber to drive out liquid fractions by centrifugal force, means for screwing the helical element into the lmaterial in the chamber, means forcontrolling the rate of longitudinal movement of the helical element so that for each revolution of the element it moves a longitudinal distance substantially equal to the pitch of the helix of said element, and means for intermittently moving said element bodily longitudinally of the chamber to advance the material toward the discharge end of the chamber.

9. Apparatus for separating the liquid and solid fractions of a material which comprises a substantially cylindrical chamber having perforated side walls and an end open for the discharge of material, means for feeding the material continuously into the chamber, a substantially cylindrical helical element disposed Within the chamber and extending longitudinally thereof, said element comprising a helical portion extending at least for one turn about the longitudinal axis thereof, means for rotating the chamber to drive out liquid fractions by centrifugal force, means for screwing the helical element into the material in the chamber in one direction, and means for moving said element bodily in the opposite direction.

10. Apparatus for separating the liquid and solid fractions of a material which comprises a substantially cylindrical chamber having perforated side walls and an end open for the discharge of material, means for feeding the material continuously into the chamber, a substantially cylindrical helical element disposed within the chamber and extending longitudinally thereof, said element comprising a helical portion eX- tending at least for one turn about the longitudinal axis thereof, means for rotating the chamber to drive out liquid fractions by centrifugal force, means for rotating the helical element at a speed which is different than the speed of the chamber, means for reciprocating said element longitudinally of the chamber, and means for controlling the rate of reciprocation to avoid substantial displacement of the material When reciprocating in one direction and to produce substantial displacement of the material when reciprocating in the opposite direction.

HENRI G. CHATAIN`