US3730422A - Continuous flow centrifuge with means for reducing pressure drop - Google Patents

Continuous flow centrifuge with means for reducing pressure drop Download PDF

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Publication number
US3730422A
US3730422A US00146758A US3730422DA US3730422A US 3730422 A US3730422 A US 3730422A US 00146758 A US00146758 A US 00146758A US 3730422D A US3730422D A US 3730422DA US 3730422 A US3730422 A US 3730422A
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United States
Prior art keywords
inlet
outlet
rotor
passageways
improvement
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US00146758A
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English (en)
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N Cho
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US Atomic Energy Commission (AEC)
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US Atomic Energy Commission (AEC)
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
    • B04B—CENTRIFUGES
    • B04B11/00—Feeding, charging, or discharging bowls
    • B04B11/02—Continuous feeding or discharging; Control arrangements therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
    • B04B—CENTRIFUGES
    • B04B1/00—Centrifuges with rotary bowls provided with solid jackets for separating predominantly liquid mixtures with or without solid particles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
    • B04B—CENTRIFUGES
    • B04B5/00—Other centrifuges
    • B04B5/04—Radial chamber apparatus for separating predominantly liquid mixtures, e.g. butyrometers
    • B04B5/0442—Radial chamber apparatus for separating predominantly liquid mixtures, e.g. butyrometers with means for adding or withdrawing liquid substances during the centrifugation, e.g. continuous centrifugation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B04—CENTRIFUGAL APPARATUS OR MACHINES FOR CARRYING-OUT PHYSICAL OR CHEMICAL PROCESSES
    • B04B—CENTRIFUGES
    • B04B5/00—Other centrifuges
    • B04B5/04—Radial chamber apparatus for separating predominantly liquid mixtures, e.g. butyrometers
    • B04B5/0442—Radial chamber apparatus for separating predominantly liquid mixtures, e.g. butyrometers with means for adding or withdrawing liquid substances during the centrifugation, e.g. continuous centrifugation
    • B04B2005/0464—Radial chamber apparatus for separating predominantly liquid mixtures, e.g. butyrometers with means for adding or withdrawing liquid substances during the centrifugation, e.g. continuous centrifugation with hollow or massive core in centrifuge bowl

Definitions

  • ABSTRACT An intermediate speed, continuous flow, high capacity liquid centrifuge assembly characterized by a low pressure drop in the process liquid is described.
  • the elongated, vertically oriented rotor contains a central, generally cylindrical core having radially projecting vanes defining a segmented annular cavity between the core and rotor wall.
  • Hollow shafts support the rotor while providing axial inlet and outlet passageways for continuous flow of process liquid through the rotor during operation.
  • Improved design of flow passages from the axial inlet passageway to respective sectors in the segmented annular cavity and from those sectors to the axial outlet passageway provides a significant reduction in pressure drops through the centrifuge.
  • a problem well known in the prior art and associated with the above-described type of liquid centrifuge involved a speed dependent pressure drop which limited throughput of process liquid both from the standpoint of instantaneous flow rates and total operating times between cleanouts, created sealing problems due to the higher process liquid pressures necessary to operate the machine, and caused undesirable shifting and compression of density gradient bands with a consequential loss of product purity. Pressure drops exceeding 15 pounds per square inch were typical at normal operating speeds of 35,000 rpm in the aforementioned centrifuge.
  • an elongated rotor contains a central core defining a peripheral annular cavity axially segmented into a plurality of sectors, axially extending inlet and outlet flow passageways at opposite axial extremities of the rotor, and a plurality of connecting passages communicating, respectively, between the inlet and outlet passageways and the plurality of sectors, the improvement comprising the connecting passages being sized so as not to enlarge the effective cross-sectional area of the inlet and outlet passageways where they communicate with those passageways. To prevent such enlargement, the connecting passages must be sized so as to terminate in a common plenum no larger than the axially extending passageways.
  • connecting passages should be sized so that the sum of their cross-sectional areas is at least as great as that of the axially extending inlet or outlet passageway which they communicate with.
  • Centrifuges made in accordance with the invention exhibit greatly reduced pressure drops which facilitate increased process liquid throughput, reduce sealing problems, and result in more stabilized gradient distributions where zonal centrifugation is practiced.
  • FIG. 1 is a vertical section view of a liquid centrifuge rotor incorporating the improvement of the present invention.
  • FIG. 2 is a partial horizontal section view of the centrifuge rotor of FIG. 1.
  • FIG. 3 is an enlarged, vertical section view of a core cap insert used in the centrifuge of FIGS. 1 and 2.
  • FIG. 4 is a top plan view of the core cap insert of FIG. 3.
  • FIG. 5 is a graph comparing the speed dependent pressure drops developed in a centrifuge made in accordance with the prior art and one incorporating the improvement of the present invention.
  • FIGS. 1 and 2 detailed vertical and horizontal section views of a centrifuge rotor assembly made in accordance with the invention are shown.
  • rotor bowl I is closed at its top and bottom ends by rotor end caps 2 and 3.
  • rotor end caps 2 and 3 Disposed within rotor bowl 1 is a hollow core insert 4 threadably engaged by core end caps 5 and 6, each of which is formed with a stepped central cylindrical cavity 7 and six radially extending grooves 8.
  • Hollow core insert 4 is provided with six radially projecting, axially extending septa or vanes 9 which divide the sample volume into axially extending sectors 11.
  • grooves 8 communicate between respective sectors 11 and the stepped central cavity 7 within each core end cap.
  • Each of rotor end caps 2 and 3 is provided with an axially extending central passageway 12 which terminates within the rotor at the apex ofa conical depression 13.
  • the other end of each passageway 12 is in communication with passageways extending through respective upper and lower rotor shafts (not shown) which drive and provide support to the centrifuge rotor assembly. Additional details relating to the rotor shafts, drive, and ancillary systems used with the rotor assembly can be found in U. S. Pat. No. 3,430,849.
  • axially extending passageways 12 are joined to radially extending grooves 8 by means of short, inclined flow channels 14.
  • Channels 14 are conveniently formed by grooving the conical end surface 15 of each insert 16 as shown in greater detail in the enlarged vertical section and plan views of FIGS. 3 and 4.
  • Conical end surface 15 is designed to mate with matching conical depression 13 in rotor end caps 2 and 3. Alignment of channels 14 with grooves 8 is accomplished by means of alignment pins 17.
  • Each conical surface 15 is urged into intimate contact with a respective conical depression 13 by springs 19.
  • channels 14 In order to achieve the full benefits of the invention and minimize pressure drops in the process liquid, channels 14 must be sized to avoid flow restriction by either reduction of flow area or the development of vortex flow in the process liquid.
  • the most critical point where reduction of flow area or vortex flow is likely to develop is in the plenum formed by the intersection ofchannels 14 at the apex of conical surface 15. That plenum serves as an inlet plenum for channels 14 where passageway 12 is an inlet flow passageway and as an outlet plenum where passageway 12 is an outlet flow passageway. Reduction of flow area is avoided by making the sum of the flow cross-sectional areas of channels 14 within each surface 15 at least as large as the flow cross-sectional area of a corresponding passageway 12.
  • Vortex flow is avoided by limiting the central opening or diameter d of the plenum corresponding formed at the apex of surface 15 to the diameter D" of corresponding passageway 12.
  • the depth of channels 14 will normally be greater than their width, which has an upper limit set by the vortex flow limitation.
  • a very close approximation of the maximum permissible width of channels 14, assuming the channels are of equal widths, may be obtained from the relationship:
  • n is the number of channels 14 in a given surface 15. Where the sum of the widths of channels 14 exceeds the circumference of passageway 12, d is made larger than D and speed dependent vortex flow develops with a resultant large pressure drop across the vortex.
  • channels 14 increase at increasing distances from the apex of surface 15.
  • Channels 14 of uniform depth and/or width may be used without departing from the scope of the invention, although a slightly greater pressure drop will occur along the channels.
  • channels 14 should be of maximum permissible width so that d equals D".
  • the channels will then intersect in the manner shown in FIG. 4 with the segmented conical face portion 17 each terminating in a sharp point in the apex region of surface 15.
  • the secondary apex 18 formed by the intersecting channels 14 should come to a sharp point as shown in FIG. 3.
  • Such configuration represents the optimum shape for inserts 16 since it maximizes the use of available flow area without permitting vortex flow to develop, provides uniform flow distribution to the various channels 14, and substantially eliminates pressure drops caused by the presence of stagnation points.
  • passageways 12 it may be desirable to increase the diameter of passageways 12 to increase its flow capacity. In that case vortex flow may develop along the length of the passageway.
  • the particular diameter where vortex flow will develop varies with the centrifuge operating speed and cannot always be predicted, although applicant has determined that passageways 12 up to 3/l 6 inch in diameter can be used without serious vortex problems.
  • axially extending septa or vanes, or fluted walls may be used to divide the passageway and thereby prevent vortex flow from developing.
  • the present invention can be employed in combination with the septa or fluted walls in the larger passageways. In that case, care must be taken to extend the septa or other anti-vortex devices the entire way into the apex of inserts 16 and the septa should be positioned to provide equal flow distribution to each of channels 14.
  • FIG. 5 the results of pressure drop tests are shown by means of a graph comparing pressure drop across centrifuge assemblies at various operating speeds.
  • the curve labeled prior art represents the speed dependent pressure drops in centrifuge assemblies made in accordance with the teachings of U. S. Pat. No. 3,430,849.
  • a pressure drop of 18.5 pounds per square inch was experienced. This point is not shown on the graph of FIG. 5, but the steep upward trend of the prior art pressure drop curve can be seen within the limits of the scale.
  • pressure drops of slightly less than 4 pounds per square inch were measured, less than one-fourth of the prior art pressure drop.
  • passageways 12 were Vs inch in diameter and six radially extending grooves 8 were used.
  • the width of each channel 14 at the apex of surface 15 was l/32 inch and its depth 1/16 inch.
  • an elongated vertically oriented rotor contains a central core defining a peripheral annular cavity axially segmented into a plurality of sectors, axially extending inlet and outlet flow passageways at opposite axial extremities of said rotor, respective inlet and outlet plenums at the inner ends of said inlet and outlet flow passageways, and a plurality of connecting passages communicating, respectively, between said inlet and outlet plenums and said sectors; the improvement characterized by said connecting passages being sized so that the sum of their flow cross-sectional areas is at least as great as said inlet and outlet flow passageways, said inlet and outlet plenums being no larger diametrically than said inlet and outlet passageways so as to avoid vortex flow conditions therein.
  • a continuous flow liquid centrifuge comprising an elongated vertically oriented rotor, upper and lower rotor end caps closing the upper and lower ends of said rotor, axially extending inlet and outlet passageways passing through the central hub portions of said rotor end caps, and a central core assembly disposed within said rotor, said core assembly defining a peripheral annular cavity axially segmented into a plurality of sectors, radially extending grooves communicating at their peripheral ends with said sectors being provided in the upper and lower ends of said core assembly; the improvement comprising: a central conical depression being provided in each of said rotor end caps and having an apex centered to register with said inlet and outlet passageways in said end caps, and a removable insert centrally disposed within the upper and lower ends of said core assembly with a conical end surface for mating with said conical depressions in said rotor end caps, said end surface of each of said inserts being pro vided with a plurality of grooves extending from the apex

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US00146758A 1971-05-25 1971-05-25 Continuous flow centrifuge with means for reducing pressure drop Expired - Lifetime US3730422A (en)

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US14675871A 1971-05-25 1971-05-25

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US (1) US3730422A (de)
JP (1) JPS544104B1 (de)
CA (1) CA946345A (de)
CH (1) CH537215A (de)
DE (1) DE2223144A1 (de)
FR (1) FR2135371B1 (de)
GB (1) GB1364331A (de)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3862714A (en) * 1970-05-08 1975-01-28 Univ Kingston Vortex clarifier
US3955755A (en) * 1975-04-25 1976-05-11 The United States Of America As Represented By The United States Energy Research And Development Administration Closed continuous-flow centrifuge rotor
WO2003045568A1 (en) 2001-11-27 2003-06-05 Alfa Wasserman, Inc. Centrifuge with removable core for scalable centrifugation
US20040214711A1 (en) * 2003-04-28 2004-10-28 Masaharu Aizawa Continuous flow type centrifuge
US20050119103A1 (en) * 2002-03-14 2005-06-02 Caulfield Richard H. Centrifugal separator
WO2006132621A1 (en) * 2005-06-03 2006-12-14 Alfa Wassermann, Inc. Centrifuge rotor and method of use
US20080173592A1 (en) * 2007-01-24 2008-07-24 Honeywell International Inc. Oil centrifuge
US20090054223A1 (en) * 2005-02-08 2009-02-26 Jurgen Mackel Separator Drum
US20170333917A1 (en) * 2016-05-19 2017-11-23 Alfa Wassermann, Inc. Centrifuge rotor core with partial channels

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE9106885U1 (de) * 1991-06-05 1991-08-14 Lindner, Jürgen H. E., Dipl.-Chem., 4220 Dinslaken Zentrifuge zum Reinigen eines Fluid von mitgeführten Partikeln

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US732886A (en) * 1901-11-11 1903-07-07 Willard A Odell Cream-separator.
US2876949A (en) * 1944-09-12 1959-03-10 Skarstrom Charles Centrifugal separators
US2947472A (en) * 1944-09-20 1960-08-02 Skarstrom Charles Centrifuge apparatus
US3201036A (en) * 1964-08-11 1965-08-17 Dorr Oliver Inc Three-product nozzle-type centrifuge
US3430849A (en) * 1967-08-01 1969-03-04 Atomic Energy Commission Liquid centrifuge for large-scale virus separation
US3602425A (en) * 1969-04-09 1971-08-31 Beckman Instruments Inc Evaporative cooling device for a centrifuge rotary seal

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US732886A (en) * 1901-11-11 1903-07-07 Willard A Odell Cream-separator.
US2876949A (en) * 1944-09-12 1959-03-10 Skarstrom Charles Centrifugal separators
US2947472A (en) * 1944-09-20 1960-08-02 Skarstrom Charles Centrifuge apparatus
US3201036A (en) * 1964-08-11 1965-08-17 Dorr Oliver Inc Three-product nozzle-type centrifuge
US3430849A (en) * 1967-08-01 1969-03-04 Atomic Energy Commission Liquid centrifuge for large-scale virus separation
US3602425A (en) * 1969-04-09 1971-08-31 Beckman Instruments Inc Evaporative cooling device for a centrifuge rotary seal

Cited By (27)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3862714A (en) * 1970-05-08 1975-01-28 Univ Kingston Vortex clarifier
US3955755A (en) * 1975-04-25 1976-05-11 The United States Of America As Represented By The United States Energy Research And Development Administration Closed continuous-flow centrifuge rotor
US7862494B2 (en) * 2001-11-27 2011-01-04 Alfa Wassermann Centrifuge with removable core for scalable centrifugation
US9050609B2 (en) 2001-11-27 2015-06-09 Alfa Wassermann, Inc. Centrifuge with removable core for scalable centrifugation
US20110136648A1 (en) * 2001-11-27 2011-06-09 Alfa Wasserman, Inc. Centrifuge with removable core for scalable centrifugation
US20050176571A1 (en) * 2001-11-27 2005-08-11 Merino Sandra P. Centrifuge with removable core for scalable centrifugation
US20050215410A1 (en) * 2001-11-27 2005-09-29 Alfa Wassermann, Inc. Centrifuge with removable core for scalable centrifugation
US20060258524A1 (en) * 2001-11-27 2006-11-16 Merino Sandra P Centrifuge with removable core for scalable centrifugation
WO2003045568A1 (en) 2001-11-27 2003-06-05 Alfa Wasserman, Inc. Centrifuge with removable core for scalable centrifugation
US7837609B2 (en) 2001-11-27 2010-11-23 Alfa Wassermann, Inc. Centrifuge with removable core for scalable centrifugation
US20100041536A9 (en) * 2001-11-27 2010-02-18 Merino Sandra Patricia Centrifuge with removable core for scalable centrifugation
SG156519A1 (en) * 2001-11-27 2009-11-26 Alfa Wasserman Inc Centrifuge with removable core for scalable centrifugation
SG156518A1 (en) * 2001-11-27 2009-11-26 Alfa Wasserman Inc Centrifuge with removable core for scalable centrifugation
US20050119103A1 (en) * 2002-03-14 2005-06-02 Caulfield Richard H. Centrifugal separator
US20040214711A1 (en) * 2003-04-28 2004-10-28 Masaharu Aizawa Continuous flow type centrifuge
US7144361B2 (en) * 2003-04-28 2006-12-05 Hitachi Koki Co., Ltd. Continuous flow type centrifuge having rotor body and core body disposed therein
US20090054223A1 (en) * 2005-02-08 2009-02-26 Jurgen Mackel Separator Drum
US7749148B2 (en) * 2005-02-08 2010-07-06 Westfalia Separator Ag Separator drum having a screw connection
US20080210646A1 (en) * 2005-06-03 2008-09-04 Horn Marcus J Centrifuge Rotor and Method of Use
WO2006132621A1 (en) * 2005-06-03 2006-12-14 Alfa Wassermann, Inc. Centrifuge rotor and method of use
US8574144B2 (en) 2007-01-24 2013-11-05 Fram Group Ip Llc Method for extracting particulates from a continuous flow of fluid
US7959546B2 (en) * 2007-01-24 2011-06-14 Honeywell International Inc. Oil centrifuge for extracting particulates from a continuous flow of fluid
US20080173592A1 (en) * 2007-01-24 2008-07-24 Honeywell International Inc. Oil centrifuge
US20170333917A1 (en) * 2016-05-19 2017-11-23 Alfa Wassermann, Inc. Centrifuge rotor core with partial channels
CN107398358A (zh) * 2016-05-19 2017-11-28 阿尔法韦士曼公司 具有部分通道的离心转子芯
US10751733B2 (en) 2016-05-19 2020-08-25 Alfa Wassermann, Inc. Centrifuge rotor core with partial channels
US11389810B2 (en) 2016-05-19 2022-07-19 Alfa Wassermann, Inc. Centrifuge rotor core with partial channels

Also Published As

Publication number Publication date
GB1364331A (en) 1974-08-21
CH537215A (de) 1973-05-31
JPS544104B1 (de) 1979-03-02
DE2223144A1 (de) 1972-12-07
FR2135371B1 (de) 1976-08-06
FR2135371A1 (de) 1972-12-15
CA946345A (en) 1974-04-30

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