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EP0104664A2 - Auswechselbarer Kraftfeldfraktionierungskanal für ein fliessendes Medium - Google Patents

Auswechselbarer Kraftfeldfraktionierungskanal für ein fliessendes Medium Download PDF

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Publication number
EP0104664A2
EP0104664A2 EP83109760A EP83109760A EP0104664A2 EP 0104664 A2 EP0104664 A2 EP 0104664A2 EP 83109760 A EP83109760 A EP 83109760A EP 83109760 A EP83109760 A EP 83109760A EP 0104664 A2 EP0104664 A2 EP 0104664A2
Authority
EP
European Patent Office
Prior art keywords
channel
slot
bowl
particulates
ring
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP83109760A
Other languages
English (en)
French (fr)
Other versions
EP0104664A3 (de
Inventor
Sushim Mukerji
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
EIDP Inc
Original Assignee
EI Du Pont de Nemours and Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by EI Du Pont de Nemours and Co filed Critical EI Du Pont de Nemours and Co
Publication of EP0104664A2 publication Critical patent/EP0104664A2/de
Publication of EP0104664A3 publication Critical patent/EP0104664A3/de
Withdrawn legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03B—SEPARATING SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS
    • B03B5/00—Washing granular, powdered or lumpy materials; Wet separating
    • 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
    • B04B5/0407—Radial chamber apparatus for separating predominantly liquid mixtures, e.g. butyrometers for liquids contained in receptacles
    • 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
    • B04B2005/045—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 having annular separation channels

Definitions

  • Field flow fractionation is a versatile technique for the high resolution separation of a wide variety of particulates suspended in a fluid medium.
  • the particulates include macromolecules in the 10 5 to the 1013 molecular weight (0.001 to 1 ⁇ m) range, colloids, particles, micelles, organelles and the like.
  • the technique is more explicitly described in U.S. Patent No. 3,449,938, issued June 17, 1969 to John C. Giddings and U.S. Patent No. 3,523,610, issued August 11, 1970 to Edward M. Purcell and Howard C. Berg.
  • SFFF sedimentation field flow fractionation
  • the mobile phase or solvent is fed continuously from one end of the channel, it carries the sample components through the channel for later detection at the outlet of the channel. Because of the shape of the laminar velocity profile of the solvent within the channel and the placement of particulates in that profile, solvent flow causes smaller particulates to elute first, followed by a continuous elution of components in the order of ascending particulate mass.
  • an apparatus is constructed for separating particulates suspended in a fluid medium according to their effective masses.
  • This apparatus includes a centrifuge bowl, means for rotating the bowl about its axis, means positioned in the bowl having an outer and inner, spaced apart, circumferential walls defining an annular slot, the bowl adapted to contain a liquid, tubing means for passing the fluid medium circumferentially through the slot, and means for introducing said particulates into said medium for passage through said slot, the improvement wherein:
  • the replaceable channel is formed of a smooth film material laminated together at its edges.
  • the channel is a laminate of three strips of a plastic film; the middle strip has its mid-portion removed and hence defines the length and width of the channel.
  • the outside strips define the inner and outer walls of the channel and, of course, the thickness of the middle strip, the thickness of the channel.
  • Inlet and outlet plastic tubes are attached to either end of the channel through the inner channel wall. These tubes extend through the inner ring.
  • split ring, SFFF channels 10 are constructed to have what is illutrated for simplicity as an outer ring 12.
  • the ring 12 is in the form of a bowl type centrifuge rotor having a constant inner radius and functions to support an inner ring 13.
  • the bowl rotor 12 may be driven directly by a centrifuge drive 14 acting through a linkage depicted by the cashed line 16.
  • the centrifuge bowl rotor 12 has a cylindrical inner surface formed thereon to provide the outer channel wall.
  • the inner ring 13 is split, i.e., its longitudinal circumference is divided or separated to have a gap 18 with the longitudinal ends 20 of the inner ring 13 slightly tapered to facilitate the use of wedges 22.
  • the wedges 22 retain the inner ring sufficiently expanded to maintain contact with the rotor 12 at all times even when stopped.
  • the radially outer wall 24 of the inner ring 13 and the radially inner wall 26 of the outer ring 56 are formed to define the channel slot 10.
  • the split ring assembly of Grant is used to form a slot 10 in which a replaceable, flat, flexible, elongated, closed channel insert 11 may be positioned.
  • a groove 24 may be formed in the outer wall of the inner ring 13 form the annular slot 10 between lands 28. No effort is made to provide the lands with a seal because. as is described below, liquid in the bowl is allowed to fill the slot 10 and surround the channel insert 11. Additionally, the upper edge of the inner ring may formed with n radial, outwardly extending flange 34, as is seen most clearly in FIG. 2, such that the inner ring may rest upon and be supported by a step in the bowl rotor 12 against axially downward displacement. Inlet and outlet conduits 36, typically stainless steel, communicate via fittings 38 with the ends of the channel insert 11 through the inner ring.
  • SFFF channel thickness of an SFFF channel is relatively small, typically being in the order of 0.1 cm or less. The dimensions of the channel, both width and thickness must be very precisely maintained. The actual thickness is selected according to the separations to be performed as is known.
  • the channel insert 11 typically is placed over the inner ring, the ring compressed (the wedges 22 being removed) and placed within the bowl rotor 12 and the inner ring 13 allowed to expand, thus forming the closed slot 10 or housing for the replaceable channel insert.
  • the wedges are then reinserted to stabilize the inner ring 13 as described by Grant.
  • This film which may be of any suitable material, provides the smooth surface for the channel walls without the need for the normal polishing that would normally be required of the channel walls.
  • the films that may be used should be flat, have a smooth surface and the desired surface chemical characteristics, be flexible, insoluble in the mobile phase used, noncorroding, and desirably colored for ease of handling.
  • the films that may be used are cellulose, polyethylene terephthalate, polytetrafluoroethylene, aromatic polyimide, polypropylene, polyvinyl ncetates, and polyvinyl propionate polyesters. These tend to provide hydrophobic surfaces. If hydrophilic surfaces are desired, the above noted materials in many cases can be treated or coated.
  • Film thickness typically should exceed 0.005 cm. Thinner films than this have a tendency to wrinkle, which is highly undesirable - for this purpose. Films up to .02 cm thickness have been used successfully. Films significantly in excess of this thickness may be used but tend to be unnecessarily wasteful of the film material and can require excessively large channel slots 10.
  • the replaceable channel or channel insert 11 may be formed by folding a strip of plastic along its length and bonding or sealing the edges. Suitable inlet and outlet tubes 30 providing access to the interior of the channel 11 are bonded at either end of the channel insert on the radially interior side when positioned in the slot 10.
  • the channel 11 is a laminate of three strips 40, 41, 42 (FIG. 5) of the plastic film used, i.e., a bottom strip 40, a middle strip 41 with its elongated center 44 removed to define the length and width of the channel and a top strip 42.
  • the strips may be bonded as heat sealed as desired.
  • the top and bottom strips 40 and 42 define the inner and outer walls of the channel with the channel thickness determined by the thickness of the middle strip 41. Tubes 30 are introduced through the inner wall 42 at either end of the center 44 and bonded to provide fluid ingress and egress to the channel.
  • a replaceable channel insert 11 of suitable dimensions is selected, positioned in the slot 10 and its tubes 30 introduced through the inner ring ports to the fittings 38 which join the tubes 30 to the tubes 36.
  • the inner ring is compressed and fitted in the outer ring 12 so that the slot 10 defines and provides structural strength and support for the channel insert 11, i.e., the replaceable channel in effect serves as a liner for the slot 10.
  • the bowl is filled with a liquid having a density comparable to that of the fluid medium to be passed through the channel 11. This equalizes the pressure about the channel during centrifugation and prevents rupture of the channel insert during operation.
  • samples of particulates in suspension are introduced into a mobile phase which carries the particulates through the channel insert 11.
  • the particulate under test will determine the mobile phase and the type of film that is used to form the channel.
  • adhesion to the channel walls can be avoided by properly selecting or coating or modifying the surface of a film. Adhesion usually occurs where the surface charge of the particulate and the film's surface polarity are opposite. It also occurs where there is covalent bonding, chemical adsorption, or van der Waals forces. Ideally the channel should "look like" the mobile phase, i.e., be of the same polarity.
  • the mobile phase density be less than the particulate density and that the mobile phase wets the particulates. If the particulates are hydrophobic, the mobile phase should be nonaqueous. If the particulates are hydrophilic, the mobile phase should be aqueous. Although of secondary importance, it is desirable that the mobile phase wets the channel walls.
  • hydrophilic surface many of the above noted polymeric films which are hydrophobic, may be surface modified. This typically is accomplished by forming OH or carboxyl groups on the surface as by chemically bonding desired molecules to reactive sites on the surface.
  • the hydrocarbons may be oxidized by a corona discharge, the fluorocarbons may be reduced by sodium in ammonia, esters, amides and imides may be hydrolyzed.
  • Cellulose and polyvinyl alcohol have hydrophilic surfaces.
  • the replaceable channel insert 11 of this invention finds use with any double ring or other type SFFF channel which can be opened for cleaning and the like and which can be submerged in a liquid.
  • it may be used in the SFFF rotors described in the copending Dilks and Yau and bilks, Yau and Kirkland applications mentioned above. These rotors are formed with a continuous inner ring 54.
  • the inner ring described by the Dilks et al. application is modified to facilitate insertion of the replaceable channel insert in the slot.
  • an inner ring 54 is positioned in the bowl of a centrifuge rotor 60.
  • the upper portion of the ring's outer radial surface is cut away to form a slot or recess 58 leaving a bottom land 59.
  • a second spacer ring 82 is formed and sized to fit over the outer surface of the inner ring 54. This permits the channel insert 11 (FIG. 5) to be fitted in the slot 58.
  • Radial slots 68 are formed in the upper portion of the inner ring to permit the inlet and outlet and, if desired, sample inlet tubes 30 to slide into position for connection to fittings 78 which are connected to the tubes 36. Dummy fittings 78' may be inserted on the opposite side of the ring 54 for balancing.
  • the inner ring 54 is formed of an appropriate engineering plastic such as Delrinl& acetal resin or Noryl@ polyphenylene oxide polymer.
  • This inner ring 54 is inserted into the bowl of a bowl-type centrifuge rotor, such as a zonal rotor 60, such that the land 59 and spacer ring 82 which defines the recess or slot 58 contacts the inside peripheral surface 63 of the rotor 60. Due to its inherent elasticity, this plastic inner ring 54 is designed to grow, as will be described below, with the expansion of the zonal rotor 60 as the centrifugal force field is increased.
  • the rotor 60 is filled with a liquid. This reduces the pressure differences between the fluid medium in the channel 10 and that outside of the channel, thus reducing leakage through the seal at the interface between the inner ring and the rotor bowl. Stress on the plastic inner ring is also reduced because it is surrounded by the liquid.
  • the liquid for filling the rotor bowl and the fluid medium for the channel preferably are selected to have densities that are about equal although fluids with densities in the range of 0.6 to 1.2 g/ml may be used.
  • This rotor 60 is adapted to be driven in a conventional manner (not shown) to rotate about the axis 62.
  • the inner ring 54 is seated in the bottom of the bowl of the zonal rotor 60 which rotates about the axis 62.
  • the rotor GO has a cover 70 that fastens onto the bowl.
  • a rotating seal (not shown) permits the passage of the fluid medium and sample, if desired, to and from the inner ring 54 via conduits 30 which connect to fasteners 38.
  • the rotating seal may be of any conventional design used to couple fluids to and from rotating bodies such as zonal rotors.
  • the rotating seal described in U. S. Patent 4,375,871 is suitable.
  • the rotating seal described in U.S..Patent 4,357,235 (Serial No. 125,854 filed February29, 1980 enti.tled "Drive for Rotating Seal” by Charles Heritage Dilks, Jr.) may be used.
  • the conduits 36 (FIG. 3) transmit the fluids from the rotating seal through a hollow drive shaft 72 for the rotating seal 28 (FIG. 5) into the rotor 60 and thence to the inner ring 54.
  • the drive shaft 72 is secured to the rotor cover 70 and the rotor cover 70 to the rotor 60.
  • the channel slot 10 is defined, as described above, by the circumferential recess 58 in the inner ring 54 and the inner wall of the rotor 60 (FIG. 3).
  • the inner ring 54 and spacer ring 82 are both formed of a suitable engineering plastic that is chemically inert, strong, and yet resilient such as the two materials mentioned above.
  • the rings may be formed of materials such as polytetrafluoroethylene, polyethylene, polyurethane or nylon.
  • One of the main criteria used for selecting the particular engineering plastic for use with high force fields is that its effective density ⁇ to tensile modulus E ratio generally should exceed the effective density ⁇ to tensile modulus E ratio of the material forming the rotor 60.
  • the effective density ⁇ of the plastic is the actual density of the plastic minus the density of the bowl filling liquid.
  • the zonal rotor bowl 60 is formed of titanium, stainless steel or aluminum. Titanium is preferred.
  • the materials of the rotor bowl and inner ring are selected as described above such that the thickness of the channel is maintained throughout operation within + 2%. This reduces separation errors.
  • the recess 58 formed in the inner ring may be formed to have different depths, different widths (by adjustment of the width of the spacer ring 82) different aspect ratios (width to thickness ratio), lengths to provide a housing. for the channel insert 11.

Landscapes

  • Centrifugal Separators (AREA)
  • Sampling And Sample Adjustment (AREA)
  • External Artificial Organs (AREA)
  • Investigating Or Analysing Biological Materials (AREA)
EP83109760A 1982-09-29 1983-09-29 Auswechselbarer Kraftfeldfraktionierungskanal für ein fliessendes Medium Withdrawn EP0104664A3 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US42747582A 1982-09-29 1982-09-29
US427475 1982-09-29

Publications (2)

Publication Number Publication Date
EP0104664A2 true EP0104664A2 (de) 1984-04-04
EP0104664A3 EP0104664A3 (de) 1985-05-15

Family

ID=23695031

Family Applications (1)

Application Number Title Priority Date Filing Date
EP83109760A Withdrawn EP0104664A3 (de) 1982-09-29 1983-09-29 Auswechselbarer Kraftfeldfraktionierungskanal für ein fliessendes Medium

Country Status (3)

Country Link
EP (1) EP0104664A3 (de)
JP (1) JPS5980346A (de)
AU (1) AU1968083A (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2686110A4 (de) * 2011-03-18 2014-10-01 Fred Senftleber Vorrichtung und verfahren zur abscheidung einer feldflussfraktionierung

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3347454A (en) * 1964-05-13 1967-10-17 Baxter Laboratories Inc Method and apparatus for the centrifugal washing of particles in a closed system
US4010894A (en) * 1975-11-21 1977-03-08 International Business Machines Corporation Centrifuge fluid container
US4430072A (en) * 1977-06-03 1984-02-07 International Business Machines Corporation Centrifuge assembly
US4387848A (en) * 1977-10-03 1983-06-14 International Business Machines Corporation Centrifuge assembly
US4283276A (en) * 1980-02-29 1981-08-11 E. I. Du Pont De Nemours And Company Rotor for sedimentation field flow fractionation

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2686110A4 (de) * 2011-03-18 2014-10-01 Fred Senftleber Vorrichtung und verfahren zur abscheidung einer feldflussfraktionierung

Also Published As

Publication number Publication date
AU1968083A (en) 1984-04-05
JPS5980346A (ja) 1984-05-09
EP0104664A3 (de) 1985-05-15

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Inventor name: MUKERJI, SUSHIM