US2518436A - Flushing assembly for centrifugal separators - Google Patents

Description

Aug. 8, 1950 v G. J. STREZYNSKI FLUSHING ASSEMBLY FOR CEN'I'RIFUGAL SEPARATORS Filed Dec. 30, 1947 u 2 HM, v2 4 5f .a w w/ m Er 5B7 Arron 5r Patented Aug. 8, 1950 UNITED STATES PATENT orrlce FLUSHING ASSEMBLY FoRoENrnIFUGAI: SEPARATORS George J; Strczynski, Red Oak Mills, N... Ya, as-

- Signor to The De Laval Senarlitor Company, New York, N. Y,., a corporation of.- New Jersey Application DecembcrKO, 1947, SerialNo. 794,668

which is-rotati'ng at high speed. Moreover, the

liquid must be fedto the bowl without interfering: with the feed of themixture to be separated or the dischargev of the separated constituents. In; prior centrifuges, the devices for feeding the flushing liquid into the bowl have not been entirely satisfactory for' various reasons, among which are the complexity of theconstructicn, the

tendency for the flush liquid to leak from the feeding device and reach the bearings or other parts of the machine which are adversely affected by the liquid, and the difficulty of removing the bo-wlfromthe frame without interferencefrom the feeding device. For example, a feeding device-commonlyemplcyed'for the flushing liquid comprises a stationary feed pipe mounted on: the

frame with its discharge end located in: an an nular recess at the central part of thebowl from which the liquid is delivered centrifugally through outwardly extending flush tubes inthe bowl to the separating chamber. The; annular recess is open toward the bowl axis to receive the stationary feed pipe, and the bowl has aninwardly extending annular ledgeforming the bottom of the recess, the discharge end of the feed pipe overlying the ledge so thatthe latter will catch the liquid dripping from the pipe. -This construction is objectionable not only because the flushing liquid leaks or spatters through the spacesurrounded by the bowl ledge, but also because the part of the stationary feed pipe overlying the ledge prevents the bowl from being lifted from the frame without first displacing or removing the feed pipe.

One object of the present invention, therefore, resides in the provision of a centrifuge having improved means for feeding flushing liquid into the separating chamber, which overcomes the above-noted disadvantages of prior centrifuges of this character.

Another object is to provide a centrifuge of the character described having a simple, compact and rugged construction for introducing the flushing liquid into the. separating bowl, in such a manner as. to prevent any substantial leakage thereof, v and vvhichv at the same time allows the bowlto. be lifted" from the frame without interference from the feeding. device in its normal position.

A centrifuge made in accordance with the in vention comprises a frame having a spindle for rotating the centrifugal bowl. The bowl is provided-with an annular recesswhich is open toward the spindle axis and from which a flushing liquid: is. adapted. to be fed. radially outwardly into the, separating chamber, the bottom of this recess. being formed by an inwardly extending annular. ledge on the; bowl: The frame: is provided with an extension winchv preferably: surrounds the:

spindle in spaced relation thereto: and projects through aspace between the. annular; ledge and. the spindle. This extension defines a passage communicating atits inlet end with a. duct for feeding a flushing. liquid. to the passage, and at: its outlet end: with the inwardly facing recess in. the bowL. The frame; extension projects axially beyond the outlet endof the. liquid passage. to. form a support; for a sleeve assembly which is. preferably removable from the support.

The sleeve-assembly functions to control the discharge; of the fhlshinav liquid from thaframepassase into the bowl recess. Horthiapurpose; the. sleeve. as,

sembly mayv include a. part. directly: orerlying the outlet end of the flush liquid passage intheframe extension. and forming withtheextension a series of; disch rge passages. extendina outwardly: and.

enerallytan entially-in he; direction of the bowl, rotation. up into; small streams which discharge at fairly hi h velocity but. in the direction, oi. movement of the, rotating mass offlush. liquid in the bowl recess. whereby splashing, dripping or leaking of the iquid through the. clearance space. adj cent: thebewl ledge is efiectiv ly'prevented. The mass-l: of.1 duid2.within.the -bowl recess is retained therein by. centrifugal force, which also causes the liquid; to flow outwardly from; the recess into the 863F327. rating chamber.

In; the preferred, construction, a further protection against leakage of the flushing liquidais; pr vided by m ns of a flexible throw-off ring: projecting outwardly from the. frame extension below; the outlet end of the liquid p ssage there-.' in, the ring,overly ns-tbeclearance space between. the bowl ledge and the frame extensionand also overlying the inner part of" the ledge. Thus, any flushing liquid. tending todrip or spatter throughthis clearance space will be deflected by thethrow-off ringinto the rotating mass of liquid In this. way. the, flush liquid is broken;

' shown).

in the bowl recess. Also, since the throw-ofi ring is flexible, it allows the bowl to be lifted freely from the frame. Preferably, an annular shield or collar rotating with the bowl extends down wardly around the upper end portion of the frame extension and its sleeve assembly, the collar acting to prevent the passage of flush liquid into the space between the spindle and the frame extension.

For a better understanding of the invention, reference may be had to the accompanying drawing, in which Fig. 1 is a vertical sectional view of part of a preferred form of the separator; and Fig. 2 is a bottom view of part of the flushing assembly illustrated in Fig. 1, showing the tangential discharge passages for the flush liquid.

In the drawing, the numeral I designates a centrifugal bowl having an annular separating chamber 2 provided with peripheral outlets 3 in the form of discharge nozzles in the outer wall of the chamber. The-mixture to be separated may be fed to the chamber 2 in any desired manner, as through an axial passage in the spindle 4 for rotating the bowl, or through the top (not shown) of the bowl. The heavier solids in the mixture will accumulate at the peripheral portion of chamber 2, due to the action of centrifugal force, and discharge through outlet 3, while theseparated lighter constituents of the mixture will be displaced inwardly in chamber 2 and discharge through a separate outlet (not shown).

In order to facilitate. discharge of the solid particles through the peripheral outlets 3, the bowl I is provided with an annular recess 5 for receiving a flushing liquid, the recess 5 being open toward the spindle 4. The bottom of recess 5 is formed by an inwardy extending ann'ular ledge 5 on the bowl, wherebya body of the flushing liquid maybe retained in recess 5 by the action of .centrifugalforce during the separating operation. From recess 5, the flushing liquid is delivered through passages 5 and flush tubes 7 in the bowlto the outer part of chamher 2 near or at the entrance tothe discharge nozzles 3. It will be understood that the liquid from tubes! is adapted to carry or flush the separated solids through the nozzles 3 as the bowl rotates.

; The bowl I is supported inany suitable mannor on the upper end (not shown). of the spindle 4, so that the bowl rotates with the spindle. Intermediate its ends, the spindle is supported laterally by a top bearing-8, the lower part of the shaft being supported by another bearing (not The bearing 8 is seated on a shoulder I on the spindle and is supported in a ring 9 mounted in'the frame I. Preferably, the ring 9 is held in the frame bya rubber cushion, springs, or the like (not shown), so that the ring and therefore the bearing are-adapted to move lat.- erally to accommodate vibrations of spindle 4; A disc II is clamped against the top-of the innerra'ce of'bearing 8, as by means of anut l2 threaded on the spindle, theperipheral part of disc II overlying the outer race of the bearing in spaced relation thereto, so as to shield the horizontal parts of these sections being clamped on the main part ll) of the frame, as by means of bolts Ill The sections l4 and I5 have vertically extending parts I l and 15*, respectively, which project upwardly and freely through the annular clearance space between the ledge 5 and the spindle. A passage l6 formed between the two sections l4 and I5 extends radially inwardly and then upwardly, as shown at I6, to a region above the ledge 5 and opposite the delivery passage 6 for the flushing liquid. The upper part [6 of the passa e is annular, so that it extends completely around the spindle. At its lower and outer part, the passage I6 communicates downwardly through an Opening I! in section I5, with a passage l8, l8 formed in the main part I0 of the frame. The passage I8 in turn, communicates at its inlet end with a duct [9 for supplying the flushing liquid to the centrifuge. Gaskets 29 and 20 are interposed at the bottom and at the top, respectively, of the lower section I5 and are compressed by tightening the bolts Ill so as to prevent leakage of the flushing liquid from the centrifuge frame.

The inner section I5*- of the frame extension Y projects upwardly beyond the outlet and of passage I5 to form a stationary support for a sleeve 22 having a threaded engagement with the section I5 A ring 22 is threaded on the upper part of section I5 and tightened against the top of sleeve 22 to lock the latter in place. The lower part of sleeve 22 is flanged outwardly, as shown at 22 and engages a ring 23 on the upper end of section Id. In its lower face, the ring 23 has tangential grooves 23 leading outwardly from the upper end of passage It and through which the flush liquid passes slightly upwardly into recess 5. Due to the tangential arrangement of the grooves 23 the flush liquid is discharged into recess 5 in the general direction of rotation of the recess wall and the mass of liquid in the recess. The resulting tangential discharge of the liquid acts to overcome the tendency for the liquid to splash'upon striking the cylindrical wall of the bowl recess 'or the liquid already in the recess, particularly when large amounts of flush liquid are being supplied to the bowl. It will be understood that similar tangential grooves may be provided in the upper end of section M in place of or in addition to the grooves 23*.

, A sealing ring 22 of rubber or the like, is compressed in a groove between sleeve 22 and section I5.

ring 25, which may be made of rubber.

overlies the inner part of the annular bowl ledge 5 An annular shield 25 is secured to the spindle in the recess 5, as by means of an insert'ring 21 and a set screw 26*, and extends downwardly around the upper part of the sleeve 22, the shield 26 being spaced from the sleeve to permit vertie cal movement of the latter.

In the operation of the centrifuge, the flushing liquid from passage I6 is sprayed outwardly through the grooved ring .23 in tangential streams.

and in the direction of rotation. From recess 5, the liquid is delivered by centrifugal; force 'through tubes I to the separating chamber.

Preferably, the rate of flow through the supply duct I9 is so regulated that a rotating'mass of the liquid accumulates in recess 5 to a vertical level which ismaintained well outsidetheinner ZB IQASQ margin of ledge 5, so that there is no danger of the. liquid overflowing the ledge. I-Io'vveverc inthe event that any of the liquid should accidentally pass through the annular space 5 between the ledge and the outer section l4, it is prevented from reaching the bearing 8 because of the frame extension I4-l 5 which, in addition to conducting the flush liquid, forms a protective caper closure over the bearing. in addition, the liquid is prevented from reaching the bearing from recess 5 through the space between the inner section {5 and the spindle, because of the shield 26.

The lower throw-off ring 25 serves to catch any liquid tending to drip from the top of the outer section Id and to deflect such liquid outwardly upon the ledge 5 or into the rotating mass of liquid in the recess. Also, the ring 25 is positioned to intercept liquid tending to splatter downwardly through. the clearance within ledge 5 from the rotating mass in recess 5, incident to spraying the liquid from passage lB In this connection, it will be observed that by sloping the grooves 23 upwardly as shown, the liquid spray is directed upwardly and outwardly so as to practically eliminate any tendency for the liquid to spatter directly downward from the rotating mass through the space 5 Thus, the spattered liquid will strike the sleeve 22 (or the sloping edge of its fiange 22 or the shield 26 and drop upon the deflecting ring 25. Consequent ly, the new construction is highly effective to prevent leakage of the liquid even upo the protective cap i4i5 for the bearing.

By reason of the tangential distribution of the liquid from the annular passage I6 the dis charging liquid is combined with and brought into rotation by the mass in recess '5 with a minimum disturbance to this mass, thereby enhancing the ability of the apparatus to provide a smooth, continuous flow of the liquid from the stationary frame to the rotating bowl, without leakage of the liquid incident to the transfer.

It will be apparent that with the new apparatus the bowl I may be lifted from the spindle 4 without interference from the means for feeding the fiush liquid, since the deflecting ring 25 can flex upwardly to allow the bowl ledge 5 to pass over it, and there is ample clearance between the ledge and both the outer section M of the frame extension and the shield .26. Moreover, the sta tionary parts l4 and for delivering the flush liquid are compact and rugged and do not interfare in any way with the operation of the bowl or the feed and discharge of the material to be separated. The ring can be expanded, due to its elasticity, to permit it to be easily mounted on or removed from the assembly. The extension l4l5 is removable from the frame to facilitate access to bearing 8.

It will be understood that the distributor ring 23 may be replaced by a ring having different distributing characteristics. Also, it may be omitted by forming the distributing grooves in sleeve 22 or in the upper end of section I i engaged by the sleeve, or in both.

I claim:

1. In a centrifuge having a frame, a spindle in the frame, and a bowl rotatable on the spindle and defining a separating chamber, the bowl having an annular recess opening toward the spindle axis and adapted to receive a flushing 'liquid to be conveyed radially outward to the separating chamber, and the bowl having a inwardly extending annular ledge forming the bottomof the recess, the combination of a pair of complementary annular stationary sections mounted on theframe concentric with the spindle and defining an annular passage surrounding the spindle and communicating at its outlet end with the recess, said outlet end of the passage being located above the level of the bowl ledge and between the spindle axis and said recess, a duct communicating with the inlet end of said passage for supplying a flushing liquid thereto, and a stationary ring mounted on one of said memhers at said outlet end of the passage and coacting with the other member "to distribute the liquid from the passage into said recess.

2. A combination as defined in claim 1, in which said ring has tangential grooves connecting said passage to the recess.

3. A combination as defined in claim 1, in which each of said sections has a stationary fiat radial portion secured to the frame and also has a sleeveportion projecting from the flat portion into the space between said ledge and the spindle axis;

4. In a centrifuge having a frame, a spindle in the frame, a bowl rotatable on the spindleand defining a separating chamber and also defining an annular recess communicating radially outwardwith the chamber and opening toward the spindle axis, and a bearing for the spindle mounted inthe frame below the bowl, the combinatlon of a stationary protective cap on the frame covering the bearing and projecting upwardly into a space located radially inwardly from said recess, the cap surrounding the spindle and being removable from the frame to permit access to the bearing, the cap defining an annular passage surrounding the spindle and communicating at its upper end with said recess, and a stationary duct connected to the cap for supplying a flushing liquid to said passage.

5. A combination as defined in claim 4, comprising also a ring mounted on the cap at the outlet end of said passage for directing flushing liquid outwardly from the cap passage into said re- CESS.

6. A combination as defined in claim 1, in which said other member and the ring have generally radial, inter-engageable surfaces at the outlet end of said last passage, whereby the flushing liquid is directed radially outward from the passage into said recess.

7. A combination as defined in claim 1, comprising also a flexible throw-off ring projecting radially outward from said other member into the recess below the distributing ring and overlying the inner portion of the bowl ledge.

8. A combination as defined in claim 1, comprising also a bearing for the spindle below the bowl, said members forming a cap overlying the bearing.

9. A combination as defined in claim 1, comprising also a shield in the recess rotatable with the bowl and surrounding part of said members with a clearance between the shield and said members.

10. A combination as defined in claim 1, comprising also a shield in the recess mounted on the spindle and surrounding part of said members with a clearance between the shield and said members.

11. In a centrifuge having a frame, a spindle in the frame, and a bowl rotatable on the spindle and defining a separating chamber, the bowl having an annular recess opening toward the spindle axis and adapted to receive a flushing liquid to be conveyed radially outward to the separating chamber, the bowl having an inwardly extending annular ledge forming the bottom of the recess and spaced from the spindle, the combination of a hollow annular extension on the frame surrounding the spindle and projecting 'upwardly therefrom through the space between the spindle and the bowl ledge in spaced relation to said spindie and ledge, the extension defining an annular passage communicating at its outlet end with the recess above the level of the ledge, the extension having a cylindrical part surrounding the spindle and projecting upwardly beyond the outlet end of said passage, a duct communicating with the inlet end of the passage for supplying a flushing liquid thereto, a ring mounted on said cylindrical part and operable to direct the flushing liquid tangentially outwardly from said passage into the recess, and a flexible throw-off ring projecting outwardly from said extension into the recess below the cylindrical part and overlying the inner portion of said ledge. I

12. A combination as defined in claim 11, comprising also an annular shield rotatable with the bowl and extending downwardly around the up-- per portion of said cylindrical part in spaced relation thereo.

13. The combination as defined in claim 11, comprising also a bearing for the spindle located below the bowl, said extension forming a removable cap overlying the bearing.

14. In a centrifuge having a frame and a bowl rotatable in the frame and defining a separating chamber, the bowl having an annular recess opening toward the rotational axis of the bowl andadapted to receive a flushing liquid to be conveyed radially outward to the separating chamber, the combination of an annular extension on the frame surrounding the spindle and projecting between said recess andthe bowl axis the extension being hollow and defining an annular passage having inlet and outlet ends, said outlet end communicating radially outwardly with said recess, a duct communicating with the inlet end of the passage for supplying a flushing liquid thereto, and a ring coacting withsaid extension to confine the discharge of liquid from the annular passage, said ring and extension having opposed surfaces extending outwardly from the passage, at least one of said surfaces having grooves extending generally tangentially in the direction of rotation of the bowl.

GEORGE J. STREZYNSKI.

REFERENCES CITED -The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date I 879,894 Peck Feb. 25, 1908 1,950,868 Streszynski Mar. 13, 1934 2,173,581 Fawcett Sept. 19, 1939 FOREIGN PATENTS Number Country I Date 7 79,024 Sweden M Jan. 28, 1932

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