US2837273A

US2837273A - Centrifugal separator

Info

Publication number: US2837273A
Application number: US564203A
Authority: US
Inventors: Frank E Sullivan
Original assignee: De Laval Separator Co
Current assignee: De Laval Separator Co
Priority date: 1956-02-08
Filing date: 1956-02-08
Publication date: 1958-06-03
Anticipated expiration: 1975-06-03
Also published as: GB802000A; DE1079550B

Description

June 3, 1958 F. E. SULLIVAN CENTRIFUGAL sEPARAToR Filed Feb. 8, 1956 INVENTOR. FrankESuIJjVarL BY l ATToRNE YS Uni-fed y States lvPatent CENTRIFUGAL SEPARATOR Frank E. Sullivan, Poughkeepsie, N. Y., assignor to The De Laval Separator Company, Poughkeepsie, N. Y., a corporation of New Jersey Application February 8, 1956, Serial No. 564,203

11 Claims. (Cl. 233-14) This invention relates to centrifuga-l separators of the type in which the material vto be separated is fed into the centrifugal bowl through a hollow axial spindle rotatable with the bowl. The invention has particular reference to an improved centrifuge of this type having means for feeding an auxiliary liquid into the bowl apart from the main feed and in such a manner that relatively heavy material separated from the feed is continuously flushed from the bowl by the auxiliary liquid without impairing the separating operation.

In the use of centrifuges for refining vegetable oils, for example, it is common practice to feed a mixture of the oil and lye or other refining agent to the centrifuge, where the soap formed by the reaction of the lye with the free fatty acids in the oil is separated as a heavier component in the separating chamber of the centrifugal bowl. The oil and the soap should, of course, be discharged separately and continuously from the bowl as lighter and heavier components, respectively; but this presents difficulties in the case of the soap due to its relatively high viscosity and its tendency to accumulate in the outer peripheral part of the bowl. lt has been proposed heretoforeto feed an auxiliary liquid, such as water, into the bowl during the separating operation, this liquid having a specific gravity such that it accompanies the heavier separated component and acts to ush this componentfrom the outer part of the bowl. However, this practice, too, has its difficulties, such as creation of an emulsion of the auxiliary liquid and the lighter component, which makes the latter difcult to separate, or impairment of the separating operation by the flow of the auxiliary liquid through the bowl.

The present invention has for its principal object the provision of a centrifuge having improved means for deliveringan auxiliary 4liquid tothe bowl for ushing out the separated heavier component, which is simple in construction, and which overcomes the above-noted difficulties.-

For illustrative purposes, the new centrifuge will be described in connection with the centrifugal separation of soap from vegetable oils, although it will be understood that the invention is not limited to this use.A

The centrifugal separator of the present invention is of the type having a hollow axial spindle on which the centrifugal bowl is mounted and which rotates with the bowl,`the spindle being rotatably mountedin a frame and havingits hollow interior communicating with the bowl at ,oneV end and with a stationary inlet at the other end, whereby the spindle formsa passage for the feed material to be separated. l

According to the invention, `a tube is secured in the hollow spindle and contains a central passage for the main feed to the bowlV (the mixture of oil and refining agent in the example previously mentioned). This tube .forms Ywithv the spindle an outer passage which is separatedv from the central passage and which serves rfor introducingY the vauxiliary liquid intol the bowl. The

2,837,273 'Patented June 3, 1958 frame of the centrifuge has two inlets, one for the main feed and the other for the auxiliary liquid; and sealed ow connections are provided from these inlets to the central and outer passages, respectively, in the hollow spindle. These passages extend into the centrifugal bowl, and the latter contains means lforming a rst generally radial passage leading from the outer passage of the spindle and terminating at the outer peripheral portion of the separating chamber in the bowl. Such means also form a seco-nd generally radial passage leading from the central passage of the spindle and terminating in the separating chamber at a region located substantially in` ward from the peripheral portion. The bowl has an outlet for discharge of "a separated lighter component from the inner portion of the separating chamber, the bowl also having a heavier component discharge passage leading from the outer peripheral portion of the separating chamber. s

With this arrangement, the auxiliary liquid is led separately vfrom the outer passagey of the hollow spindle to the peripheral portion of vthe bowl, so that this liquid does not mix with the lighter component of the feed material entering the bowl from the central portion of the spindle. Thus, the auxiliary liquid serves to dilute the soap and unreacted lye separated as a heavier component from the oil and to flush this heavier component from the peripheral part of the bowl through the heavier component discharge passage, without forming an emulsion with the oil or otherwise imparing the separating operation.

In the preferred form of the new centrifuge, the passage forming means in the bowl include a hollow member dening a second chamberin the bowl, the central passage of .the spindle opening into the central portion of this second chamber and the latter having an opening in its outer peripheral portion through which thefeed material passes into the main separating chamber'of the bowl.' The bottom yof this hollow member is located above' the bowl bottom and defines therewith a generally radial channel leading to the outer peripheral part of the main separating chamber, the auxiliary liquid being delivered into this channel through a lateral opening in the hollow spindle. Thus, they bottom of the hollow member forming the secondary chamber for the feed material in the fbowl also serves to maintain the feed material separated from the auxiliary liquid as the latter passes to the outer portion of the separating chamber to flush away the separated heavier component.

These and other vfeatures of the invention will be better understood by reference to the accompanying drawing, in which:

Fig. 1 is a side elevational view, partly in section, of a preferred form of the new centrifuge, showingv the bowl, the upper part of the hollow spindle and the sealed How connections for leading the separated components to stationary discharge outlets;

Fig. 2 is a vertical sectional view of the lower part of the centrifuge illustrated in Fig. 1, showing thesealed flow connections from the stationary inlets to the lower ends of the passages inthe hollow spindle;

Fig. 3 isan enlarged vertical sectional view of the upper part of the centrifuge, showing details of the sealed flow connections from the bowl outlets, and

Fig. 4 is a sectional view on line 4--4 in Fig. 2.

Referring to the drawings, the centrifuge as illustrated' to those Skilled -in the art. A hollow member 14 is located in the lower part of the bowl where it rests upon the bowl bottom 15. The hollow member 14 tapers upwardly from the bowl bottom and has a bottom 14a closely surrounding a central nave 16 which isintegral with the bowl bottom and extends upwardly therefrom. Atits: lower portion, thev nave 16 has an annular external shoulder 16a on which the botom 14a of the hollow member, rests. Y

The hollow member14 serves as .a carrier for the discs 13,..the. lowest discA in the -stack resting on .the conical surface of the'hollow member.. A center post 1419 extends upwardly from thehollow `member 14and through central openings infthe discs `13. At `their inner edges the discs a13 have clearances 'withjthe center post 14h to provid'eor upward passageof the lighter componentsepa'rated between Athe1discs, as will be Idescribed in greater detail presently. -When.the bowl top 11 is removed from the y.shell 10,the discs.- 13 'and thev :discs carrier 14-14!) canbe lliftedias a unitfrom theshell.

The centrifugal bowl .10+f12 is rotatable on a hollow axial spindle 18. This spindle has a tapered upper end portion 13a which tits into the correspondingly tapered interior of the nave 16, so that, the bowl is supported on the spindle by the nave. A hollowinut 19 is lscrewed on the upper end of thetapered spindlelportion 18a and engages the upper end of 'the naveto prevent lifting of the bowl from the spindle. ,The spindle 18 is lmounted for rotation in a stationary frame, partfof which is shown at 21 (Fig. V2).. V rl`lie mounting of` the vspindle in the frame may be effected by a lower bearing assembly 22 of conventional formnand the usual upperbearing assembly (not shown). It will beiunderstood that by means of these bearing assemblies, the bowl and spindle are supported in the frame for rotation 'aboutthe axis of the spindle, the bearing assemblies permitting a limited amount of radial moyementof the bowl during its rotation, as is conventional' inqthe art. 4The bowl may be rotated byl any suitabledriying means, such as an electric motor (not shown) having a driving connection to the Spindle' 1., Y

- At its lower end, thefspindle -18 has Jan enlarged angel23 threaded von Lthespindle below the bearing assembly 22, this flange Aforming `a downwardlyV opening recess. Withinjthe Yspindleis atubie 25, the lower end of which extends into theurecesswformedby flange 23. ThisY tube has anexternalgdiameter somewhat less than the linternal diameter of theL hollow'spindle, except at the'upper portion 25a ,(Fig..- l) "of the tube, wherethe latter tits closely into the spindle. v The-upper end ofthe tube 25 may beseucurednin anyfdesiredmannerto the spindle, as by means ofgmating threads onlthe outside of the tube -`andj onthe inner wallc)fL the hollow spindle. The lowerendwof'the tube25 is closelysurrounded by a sealing collar 26 located within the flange 23and having radial .spokes-26a extendingoutwardlyinto engagement with the cylindrical'inner wall ofthe ange. Therefore, the lower end of the tube 25 isheldbythe spokedfcollai 26 against lateral movement relative `tothe spindle 18, and the upper end lof the tubefis secured directly to the spindle to preventlateral .and-longitudinal movement of the tube relative to the spindle. Thus, the tube 25 rotates with the spindle and forms therewith an annular outer passage 27 surrounding the centralpassa'ge dened by the tube itself. 1 n l i* A stationary iitting A.21a`fis removably'mounted on` the frame 2l. Thishtting hasafrai edfinlet-29Hto which the mixture of vegetable 'oilandre'fininggnt is delivered under pressure through a supply pipe. Al passage 3i? extends upward Vfrom the inlet29into yan'enlarged-recess l 31 in thetting 21a. 1A tuben32 is 'se/cured'at vits lower end to the bottom of recess "31and 'forms an upward extension of .the passage 30.y .In thefiipperv part of the tube 32 vis a sealing collar 3 3 which 'tits closely in the tube and is slidable axially therein. The collar 33 is 'i pressure, to the recess .31.

urged upward against the sealing collar L26 by a coinpression spring 34 arranged within the lower part of tube 32.

A nipple 36 is threaded into the side wall of the stationary fitting 21a, and an auxiliary feed line 37 communicates through this nipple with the outer part of recess 31 surrounding thevtube 32. The feed line 37 serves to deliver an auxiliary liquid, such as water, undery In the upper part of the recess 3lA is an outer sealing collar 33 which fits closely against the cylindrical inner wall of the recess, this collar being slidable axially of the spindle 18. A compression spring 39 is seated on the bottom of recess 31 and urges the outer collar 38 upwardly against the lower end4 of the ange 23. f l

it will be apparent that the tube 32, the enlarged ange 23 and the collars 26-33--38 form sealed ilow connections from the

stationary inlets

29 and 36 to the central passage in the tube 25 and the annularpassage 27,lre spec tively. That is, the feed material flows upward from inlet 29.through passage 30,. the interior of tube.32 and collar 33 to the centralpassage in tube 25 by way 'of the collar 26; and the auxiliary liquid hows upward from the outer part of recess 31 through the annular space between tube .32 and collar 38, andbetween the spokes 26a to the lower end of the annular passage 27. The inner collar 33, by virtue of its sealing contact with the tube 32 and opposed collar 2,6, seals .the flow of thc main feed from the lflow of the auxiliary liquid. Similarly, the outer ring.38, :by virtue of its sealing contact with ange 23 and theinner wall of recess'l, seals the flow of the auxiliary liquid :from atmosphere. Any accidental leakage 'of the :auxiliary .liquid -may be discharged fromvthe interiorxof the fttinglla .by way -oi escape holes 21e. llt willbe .apparent that-the 'flange 23 and thecollar 2,6,can slide'l'aterally, on the sealing `

collars

38 and 33, respectively,:whilemaintainingsthe.sealed flow connections, so as to `accommodate :thelipreviously mentioned movements of the'bowlduring itsrotation.

The lower ends of the spindle 18'andtube-f25 .are readily accessible by removing the vfitting21afafrom1the frame 21. This permitsv the ange 23 to be unscrewed from the lower end of spindle 18, whereby the..bowl 10-12 and spindle 18 can be liftedfasfafunit from. lthe frame. Also, removalof the ittin'g 21a fromtheframe permits easy access to the sealing collars 26, `33 and-38 for inspection' or replacement. The feed material passes upwardly from thespindle tubev 25 into the hollownut 19, fromy Awhich thewfeed material discharges outwardly through radialholesfa in the nut and flows into the central'upper. .portion of the secondary chamber in the hollow member 14.

secondarychamber may be .provided ywith radial :wings understood that the discs have holes aligned vertically with the holes 14C, whereby thei-feedfmaterial can pass directly into the separating spaces between the discs.,-`

The .spindle 18 and the nave v16 are-provided `with aligned radial holes 41 located just below the level of the bottom 14a of the hollow disc carrier 14.*Y 'Iheseyholes extend fromy the upper end ofthe outer passage -27 in the spindle to a recess in` the lower faceof thebottom 14a of the hollow disc carrier, as shown in Fig. .1. -Radial wings or vanes 42 are located in this recessjandsecured to the lower faceof the bottom 14a. h'lhes'e wings generally radial channels :extending outwardly -to.radial '5 v channels 42a formed inthe bowl bottom 1S. The latter channels extend under thelower edge of the periphery of thev hollowr member 14 and open into the main separating` chamber under the outer edge portion of the lowermost disc 13, as shown in Fig. 1.

It will be apparent that the hollow member or disc carrier 14 constitutes a means in the bowl forming the generallyv radial passage leading from the central passage in the spindle tube by way of the hollow nut 19 and the secondary chamber within the hollow member 14 and terminating at the holes 14e in the main separating chamber at a region located substantially inward from the outer peripheral portion of the latterchamber. ,I The hollow member 14 in conjunction with the holes 41 and the bowlbottom 1S also constitutes a means forming a generally radial passage leading outward from the spindle passage 27 by way of the channels between the radial wings 42 and the channels 42a and terminating at the outer peripheral portion of the separating -chamber below the discs. Thus, the auxiliary liquid is led from the outer passage v27 in the j spindle throughthis generally radial passage, separately vfrom the main feed, and flows under the lower or outer edge of the bottom disc 13 into the peripheral portion of the bowl.

Due tothe centrifugal force generated in the revolving bowl, the feed material is separated between the discs 413 into oil as a lighter component and soapv and unreacted lye as a heavier component.v The separated oil is displaced inwardly between the discs and ilows upwardly Atoward the top of the bowl through the clearance spaces between the center post 14b and the inner edges of the discs. From this central portion of the bowl, the oil flows into a central discharge passage 44 in the bowl neck by way of holes 45 leading into a recess in` the upper portion of center post 14b, this recess opening upwardly into the discharge passage 44. The heavier component ows outwardly from the disc spaces into the peripheral portion ofthe main separating chamber, where it is joined by the llush water or auxiliary liquid intro duced under the outer edge of the bottom disc 13. This liquid dilutes the heavier component and flushes it up# wardly toward the top disc 46 which is of somewhat greater diameter than the discs 13. The diluted heavier component passes around the outer edge of the top disc 46 and upwardly and inwardly through a space 47 between the top disc 46 and bowl top 11.V This space forms discharge passages for the heavier componenty leading to an annular outlet 48 in the bowl neck. The

outlets

44 and 48 extend upwardly and through the bowl neck and are separated from each other by an annular part 49 of the neck.

Above the bowl 10-12 is a stationary itting S1 having an outlet 52 for the lighter component and an outlet 53 for the heavier component. The

outlets

52 and 53 have sealed flow connections with the

bowl outlets

44 and 48, respectively. These ow connections may be arranged as disclosed in my copending application Serial No. 480,009, tiled January 5, 1955. These flow counections comprise a stationary tube assembly 5'5 in the hollow fitting 51 forming an upward extension of the central outlet or discharge passage 44 in the bowl neck, this extension leading upward to the stationary outlet 5.2. Fitted closely in the lower portion of the tube assembly 55 is an inner sealing ring 56 which is slidable vertically in the tube assembly, this ring being spring-biased downwardly against the annular part 49 of the bowl around the outlet 44. An intermediate sealing ring 57 closely surrounds the tube assembly 55 at its lower portion and is spring biased downwardly against the outer portion of the annular part 49 of the bowl. An outer'sealing ring 58 is closely surrounded by the inner wall of the tting 51v and is spring biased downwardly against the outer annular part of the bowl neck around the heavier component outlet 48. The heavier component from the outsanar-s' let 48 passes upward betweenV the sealing rings 57--5'8n and into the space surrounding the tube assembly v55, from which it discharges through the stationary outlet 53. It will be understood that the sealing rings 56-57-58 permit lateral or radial movements of the bowl while maintaining a sealed outlet path for the lighter kand heavier separated. components, as previously described.

The present invention provides a simple but highly effective arrangement, in a centrifuge of the khermetic type, for delivering both the main feed and an auxiliary liquid under pressure and apart from each other through the bowl spindle to the centrifugal bowl and leading the auxiliary liquid directly to the outer portion of the main separating chamber, where it joins the heavier separated: The

component and flushes the latter from the bowl. threaded connection between the upper end of the spindle 18 and its contained tube 25, together with the spoked collar 26a surrounding the lower end of this tube in the flange 23, constitute a simple means for positioning the tube in the spindle to form the annular outer passage 27, such means permitting the tube to be readily disassembled from the spindle. The hollow member 14 serves not only as a carrier for the discs 13 but also as a means coacting with the bowl parts 15-16 to form generally radial passages through which the main feed yand the auxiliary liquid are ledseparately from the spindle tube 25 and the spindle passage 27 to the intermediate and outer portions, respectively, of the main separating cham-r ber in the bowl.

I claim:

l. in a centrifugal separator having a centrifugal bowl provided with a separating chamber a hollow axial spindle secured to the bowl and rotatable therewith, and a frame rotatably supporting the spindle and having two stationary inlets, the combination of a tube secured in the hollow spindle and rotatable therewith, the tube containing a central passage and forming with the spindle an outer passage separate from said central passage, sealed flow connections from said stationary inlets to said passages, respectively, said passages extending into the bowl and means in the bowl forming a rst generally radial passage leading from said outer passage and terminating at the outer peripheral portion of the separating chamber, said means also forming a second generally radial passage leading from said central passage and terminating in the separating chamber at a region located substantially inward from said peripheral portion, the bowl having au outlet 'for discharge of a separated lighter component from the inner portion of said chamber, the bowl also having a heavier component discharge passage leading from sai-d peripheral portion of the separating chamber.

2. The combination according to claim l, in which the frame also has two stationary outlets, the combination comprising also sealed flow connections from said bowl outlet and discharge passage to said stationary outlets, respectively.

3. The combination according to claim l, in which said passage forming means include a hollow member deiining a second chamber in the bowl, said central passage opening into the central portion of the second chamber, the hollo-w member having an opening in its outer peripheral portion, said opening and second chamber each forming part of said seco-nd generally radial passage.

4. The combination according to claim 1, in which the bottom of the bowl has a hollow nave extending into the bowl and receiving one end portion of the spindle, said first generally radial passage including generally radial holes in the spindle and nave.

5. The combination according to claim l, in which the bottom of the bowl has a hollow nave extending into the bowl and receiving one end portion of the spindle, said first generally radial passage including generally radial holes in the spindle and nave, said central passage extending upward in the spindle above said holes, said secondgenerally radial passagebeing locatedabove said firstgenerally radial passage.

`..6. The coriibinationY according lto claimgfl, int. Which said passageformingme'ans vinclude a hollow rnember defining a second, chamber in thebowl,' said central passage openingdinto `the central portionof the second chamber, the hollow member having an opening in its outer 'peripheral portion, said opening and second chamber Aeach forming part of said secondggenerally radial passage,`said hollow member having a bottom, located above the bowl bottom and dening therewith a general-` ly..ra'dial 'channel forming part of said rst generally radial passage.

7."'The combination according to claim l, in which the` bottom of the bowlI has a hollow nave extending into the bowl and receiving one end portion of the spindle, said rst' .generally radial passage including generally radialholes inthe spindle and nave, said passage forming means yincluding a hollow member defining a second chamber surrounding the nave in the bowl, said central passage extending upward in the spindle above said holes and opening into the central portion of the second chamberfthe hollow member having an opening in its outer peripherall portion, said opening and second chamber each forming partk of said second generally radial passage meansythe hollow member having a bottom surrounding the naveabove said holes and defining with the bowl bottom 4agenerally radial channel into which said holes openfsaid channel formingpartof said first generally radial passage. i

8. Thecombination according to claim 1, in which the'spindle has-an enlarged hollow flange at one end, said tubeprojectinginto theinterior of the flange, said sealed flow connectionsl including an outerl sealing ringpressed against said flange,y a sealing collar yon the tubewithin saidilange and havingf-generally radial/spokes extending.

passage `forming means' constitutingv a carrierfor the.

disc...

l0. The combination accordingfto claim l, comprising also a set-,of conical discsv inthe separating chamber',l said. passage'forming fme'ans including a hollow rnemben'suptlie'discs' and defining a second chamber inthe b fl,s c'l` generally radial passage. 4

ll. 'The combination according, to claim l, comprising also ai set or" conical discs in' the separating chamber`said passage forming .means .including -a hollow ymember supporting theiiscs and dening a second chamberinfthe bowl, said second chamber forming part of saidfsecond generally radial passage, the hollow member also dening'with 'the bottom ofthe bowl a' separate channell forming part of said first generally radial passage andjleading into the separating chamber around` the outeredge .of the bottom disc in said set.

A2,628,021 stamt r Febp1ai9'53 second chamber .formingfpart of saidI second.