EP1272277B1

EP1272277B1 - Circumferentially driven continuous flow centrifuge

Info

Publication number: EP1272277B1
Application number: EP00973959A
Authority: EP
Inventors: William Aitkenhead; Glen Jorgensen; Robert L. Standley
Original assignee: ZymeQuest Inc
Current assignee: ZymeQuest Inc
Priority date: 1999-10-28
Filing date: 2000-10-27
Publication date: 2010-08-11
Anticipated expiration: 2020-10-27
Also published as: EP1272277A1; EP1272277A4; ATE477057T1; JP5147154B2; EP2243554A2; ES2349888T3; HK1053804A1; DE60044823D1; EP2243554A3; JP2010284651A; JP2003514645A; WO2001030505A1

Abstract

There is disclosed a multi-lumen rope comprising a plurality of elongated tubes for delivering one or more fluids between a first fluid containing mechanism and a fluid receiving rotatably driven rotor, one end of the rope being attached to the center of the driven rotor, the other end of the rope being attached to the first fluid retaining mechanism, the first fluid retaining mechanism being mounted on an opposing side of the rotor and such that the point of attachment of the other end of the rope is substantially coaxial with an axis of the rotor, said elongated tubes comprising at least one tube disposed in a spiral wrap, wherein one end of the rope has a right hand twist and the other end of the rope has a left hand twist.

Description

BACKGROUND OF THE INVENTION

The present invention relates to centrifuge apparati and more particularly to a centrifuge which works in conjunction with a cassette, rotor or other device having fluid retentive chambers and fluid flow tubing fixedly attached to the axis of the device.
In the context of mechanisms which have come to be known as continuous flow centrifuges, when a length of tubing is fixedly attached to the rotation axis of a device which contains the fluid material to be centrifuged, the entire length of tubing must be rotated by use of rotary seals or some other means to avoid twisting the tubing. A well known method for avoiding the use of rotary seals is to curve the length of tubing outwardly from the axis and around the outer edge of the circumference of the rotor, cassettes or the like and, to rotate the tubing in an orbital fashion around the rotor/cassette at one-half times the rotational speed of the rotor/cassette itself. Such a method for eliminating tube twisting and apparati therefore are disclosed, for example, in U.S. Pat. Nos. 4,216,770 , 4,419,089 and 4,389,206 .
Problems inherent in such prior apparatuses which orbit the fluid flow tubing around the axis of centrifuge rotation are that the axis of rotation is disposed vertically, the tubing is routed through an axial shaft and the apparatus is driven by driving an axial shaft which requires a high aspect ratio and an elongated shaft which limit the rotational speed, render the apparatus instable and limits the ability of the user to mount a second cassette, rotor or the like on opposing sides of the chuck component of the apparatus.
In accordance with the foregoing, reference is also made to U.S. Pat. No. 5,665,048 that provides a centrifuge for rotating a fluid retentive housing having fluid input and output tubing fixedly connected to a rotation axis of the fluid retentive housing, the centrifuge comprising: a frame; a first rotatable mechanism having a rotation axis, the fluid retentive housing being coaxially mounted thereon for co-rotation therewith; a second rotatable mechanism having a rotation axis, the first and second rotation mechanism being coaxially mounted on the frame; the second rotatable mechanism having an outer circumferential surface engaged with a drive mechanism, the drive mechanism driving the outer circumferential surface such that the second rotatable mechanism rotates at a selected rotational speed X; the first rotatable mechanism being interconnected to the second rotatable mechanism such that the first rotatable mechanism rotates simultaneously with the second rotatable mechanism at a rotational speed of 2X.
The second rotatable mechanism includes a seat for holding a distal length of the output tubing which extends from the axis of the fluid retentive housing, wherein the distal length of the output tubing held by the seat is rotated around the rotation axis at the same rotational speed as the second rotatable mechanism. One of the problems associated with such an arrangement is that there is continuous friction between the tubing and the seat.
US5431814 discloses a rotary filtration apparatus for separating a selected material suspended in a fluid, the apparatus comprising a housing having a selected axis of rotation, the housing being rotatably mounted on a rotation device which rotates the housing about the selected axis of rotation of the housing; the housing sealably enclosing and defining a fluid sealed cavity extending radially outwardly from the axis of the housing; a filter mounted within the cavity of the housing such that the cavity is divided into at least a first fluid retentive input chamber and a second fluid retentive output chamber, the input and output chambers being disposed on opposite sides of the filter; a fluid input line sealably communicating with the fluid input chamber for feeding the material suspended in the fluid into the input chamber under a selected pressure; the filter being selectively permeable to the fluid under the selected pressure and selectively impermeable to the selected material under the selected pressure, the fluid being fed into the input chamber flowing through the filter and into the output chamber under the selected pressure; a fluid output line sealably communicating with the input chamber for receiving and routing fluid which is fed into the input chamber out of the input chamber; the rotation device drivably rotating the housing around the axis such that the material suspended in the fluid in the input chamber is forced to travel under centripetal force in a radially outward direction from the axis.
US4865081 discloses a multi-lumen tube arrangement for use in a sliding-seal-free centrifuge comprising a plurality of equilength individual tubes which after a twisting about the longitudinal axis of the tube arrangement are each held fixed free of tension at their ends.
US2832374 discloses a flexible conduit assembly comprising spaced, pierced flange members, a plurality of flexible tubes secured at each end thereof to one of said flanges in register with an opening therein, said tubes being helically disposed about one another.
US3646972 discloses information transmitting systems including a plurality of tubular members for pneumatically or hydraulically passing data in pulse form; the tubular members being stranded about a core member which may be tubular or in electric cable form, the tubular members being stranded with a reverse lay to allow such members to be displaced to allow convenient tapping of the tubular members or the core member.
US4018304 discloses a lubrication system for a centrifugal liquid processing apparatus or the like having a bearing subject to operation in a centrifugal force field includes a reservoir wherein a quantity of fluid lubricant to be applied to the bearing is contained, an accumulator for receiving lubricant from the bearing, a first flow path from the reservoir through the bearing to the accumulator, and a second flow path from the accumulator to the reservoir. During operation of the apparatus lubricant is forced by the centrifugal force field to flow along the first flow path from the reservoir, through the bearing and into the accumulator under pressure. When the apparatus is stopped, lubricant is forced to return from the accumulator along the second flow path to the reservoir. An orifice is provided in the first flow path to control the flow and pressure of the lubricant within the bearing, and check valves are provided to restrict the lubricant to a circulating route through the bearing.
US4163519 discloses a 2:1 compensating rotor is used in a continuous-flow centrifuge system, thereby allowing the dynamic loading and unloading of biological suspensions and processing solutions in a "closed" fashion without resort to rotary seals. Improved high speed performance is obtained by utilization of an inherently symmetrical load sharing epicyclic reverted gear train. The effective lifetime of the component gears is increased due to the load sharing feature of the symmetrical epicyclic reverted gear train.
US4221322 discloses a 2:1 compensating rotor is used in a continuous-flow centrifuge system, thereby allowing the dynamic loading and unloading of biological suspensions and processing solutions in a "closed" fashion without resort to rotary seals. Improved performance is obtained by relieving the mechanical stresses associated with the 2:1 relative motion between rotary components. In zones of high flexural and torsional stress low-friction bearing mounted tube constraint fittings are utilized to minimize tubing loop wear and risk of rupture. Similarly, in regions of high centrifugal force a tube guide insert is utilized to separate and constrain the discrete fluid-carrying tubes, thereby minimizing abrasion induced by the relative motion between the discrete tubes, as well as minimizing abrasion induced by the relative motion between the discrete tubes and the inner walls of the tube guide assembly.
US4425112 discloses a flow-through centrifuge free of rotating seals. The centrifuge includes a frame having three spaced apart horizontal plates which carry a central bowl, a countershaft and a tube-supporting hollow shaft. A motor is arranged to drive the frame at an angular velocity of omega. The countershaft is driven by a stationary pulley on the motor and drives the bowl at an angular velocity of 2 omega. The motion of the countershaft is also transferred to the tube-supporting hollow shaft by a pulley coupling having a ratio which effects rotation of the hollow shaft, with respect to the frame, at an angular velocity of - omega.
US4459169 discloses a rotatable processing bowl assembly adapted for mounting in a centrifuge includes an umbilical tubing system formed of a plurality of individual flexible tubes each of which communicates with the processing bowl. Each tube has an exterior wall and includes a first portion extending adjacently from the bowl and a second portion which is spaced from the bowl. The exterior walls of the tubes are bonded together along their first portions so that the joined exterior walls collectively define the outer periphery of the tubing system along the first portions of the tubes. Preferably, the tubes are also wound to form a predetermined helical pattern along their first portions. This arrangement enhances the tubing system's durability and resistance to fatigue along the bonded together first portions, particularly at higher rotational speeds, and permits direct, facile connection of the free and unattached second portions with external apparatus.

SUMMARY OF THE INVENTION

Therefore, in accordance with the present invention, there is provided an improvement in a centrifuge, and, in particular, an improvement relating to fluid tubing by the support thereof. In accordance with the present invention, there is provided a centrifuge for rotating a fluid retentive housing as defined in either of claims 12 or 24.
In accordance with another aspect of the present invention, there is provided a multi-lumen rope comprising a plurality of elongated tubes as defined in claim 1.
Preferred embodiments are given in the dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a centrifuge apparatus according to the invention;
FIG. 2 is a perspective view of a portion of the apparatus of FIG. 1, particularly, the support arm;
FIG. 3 is an exploded perspective view showing the support arm with end guides and the fluid retentive housing with fluid tubing;
FIG. 4 is an exploded perspective view showing the components of the fluid retentive housing and fluid tubing; and
FIGS. 5A-5H disclose various separate embodiments of the fluid tubing or multilumen rope as in accordance with the present invention.

DETAILED DESCRIPTION

FIG. 1 shows a centrifuge apparatus 10, the basic construction of which may be substantially the same as that described in U. S. Pat. No. 5,665,048 . As far as the invention of the present invention is concerned, this relates more to the tubing 70, and, in particular, its support from the centrifuge apparatus 10. The support includes the support arm 50 as well as its guide members 52 and 54.
As indicated previously, the basic structure of the centrifuge apparatus 10 may be the same as that described in U. S. Pat. No. 5,665,048 . U. S. Pat. No. 5,665,048 is thus hereby now incorporated by reference herein. This apparatus includes a bag set 20. This may also be referred to as aself-contained fluid retentive centrifuge cassette or rotor which is mounted on an inner-rotatable chuck 60. The bag set 20, as illustrated in FIGS. 1 and 3, has fluid input and output 70 coaxially and fixedly attached to the axis 40 of the cassette 20. As shown, the cassette is mounted on the chuck 60 such that it's rotation axis is coaxial along common axis 40. Thus, as the chuck 60 rotates, the fixedly attached tubing 70 co-rotates therewith. As shown, there is a length 72 of the tubing 70 which extends axially outwardly from the area of the fixed attachment 71. The length 72 of tubing is curved axially backwardly toward and extends through a radially outer, separately rotatable pulley 90 which rotates, by virtue of a gear train interconnecting the pulley 90 and the chuck 60 at a speed of XRPM while the chuck rotates at a speed of 2XRPM. Again, reference is made to U.S. Pat. No. 5,665,048 which is incorporated by reference herein regarding the operation of the chuck and pulley arrangement. FIG. 1 actually shows the cutaway section indicating the chuck 60 and a further cutaway section showing a gear 91, part of the aforementioned gear train.
In operation, as the pulley 90 rotates, the backwardly curved length 72 of the tubing is rotated around axis 40 at a rate of XRPM while the fixedly attached end 71 of the tubing 70 is actually rotated at a rate of 2XRPM. This phenomenon is well known in the art as enabling the tubing 70 to avoid twisting around its axis even as the cassette 20 and the chuck 60 forced the tubing 70, 71 to be axially rotated. A fuller description of this phenomenon is described in U.S. Pat. No. 5,665,048 as well as in U.S. Pat. No. RE29,738 ( 3, 586, 413) (Adams ).
Now, reference is further made to FIGS. 2 and 3 which illustrate the support arm 50. The support arm 50 at its central section 56, is fixedly attached to an inner-periphery of the pulley 90. Thus, the support arm 50 rotates with the Hub 90.
The support arm 50 is of elongated shape and extends on either side of the centrifuge apparatus 10, as illustrated in FIG. 1. As illustrated in FIG. 2, the support arm 50 has an elongated channel 58 which receives the support tube 80. The support tube 80 is actually supported in the channel 58 by means of a pair of bearings 82 illustrated in FIGS. 3 and 4. Each of these bearings is accommodated in a corresponding recess 84 at opposite ends of the support arm, as illustrated in FIG. 2.
Thus, the support arm 50 is fixedly attached to the pulley 90, the support tube 80 is supported within the channel and support arm by means of bearings 82 and then the fluid tubing 70 extends through the support tube 80, but in this regard, FIG. 1 shows all of these various components in their final assembled state. The fluid tubing 70 is shown being guided by a C-shaped guide member 52 into one end of the support tube 80. At the other end of the support tube, the fluid tubing length 72 extends out of the support tube and into the S-shaped tubing guide 54, as also illustrated in FIG. 1.
When the fluid tubing is in the form of a multi-lumen rope, embodiments of which will be described hereinafter, the elements of the rope furthest from the access of rotation exert large forces against the supporting surface and consequently produce large frictional forces impeding the twists required to make the slip rope function. It has been found that the following perimeters are desirable for proper operation of a multi-lumen skip rope;

1) strong but flexible skip rope assembly;
2) ability to transmit torque without damage to the rope;
3) low friction between rope and supports particularly far from the rotational axis where the g-field is high.

Parameters 1 and 2 are generally met by selecting relatively small diameter, high durometer thermoplastic tubing. Gluing methods and fixtures were used so that an assembly of at least 9 lumens could be well fabricated with very uniform tubing lay and therefore stiffness and strength. This assembly is of a spiral wrapped construction to improve uniformity.
Reference is also now made to FIGS. 5A-5H for various designs of the rope. FIG. 5A shows a single strand 100A counterclockwise wrap while FIG. 5B shows a multi-strand 100B counterclockwise wrap. FIG. 5C shows a single strand 100C clockwise wrap, while FIG. 5D shows a multi-strand 100D clockwise wrap. Through testing and observation, it is found that the two ends of the skip rope behave asymmetrically. This is due to the fact that one end is twisting clockwise and the other end counterclockwise. One end tends to twist up while the other end untwists. Thus, it has been found that in accordance with one embodiment, during the rope fabrication, the twist direction may be reversed in mid-rope. In this regard, refer to FIGS. 5A, 5F and 5H. It is noted that a small section of the rope in the middle has no twist. By doing so, one may install the rope so that both ends see the same twisting condition. The rope may be installed so that both ends twist up to yield maximum torque stiffness so that both ends untwist to produce minimum restriction to fluid flow in the tubes.
In accordance with the present invention, in order to provide the desired low friction, relating to the fluid tubing, it is noted that portions of the skip rope progress through curved supports from the access of rotation from the periphery where the rope is guided through very smooth, Teflon, hard coated aluminum parts. Please refer to FIG. 3 and guide members 52 and 54. That in these areas, the co-efficient of friction between the skip rope and the guides is preferably less than 0.2.
The portion of the skip rope at the maximum radius from the center of rotation is a straight section of various lengths. This section can be very important to the overall torque needed to twist the rope. Indeed the weight of the skip rope assembly (plus fluids if it is filled) is increased by the G-field which may be a multiplier of 1,000 or more. To reduce the torque needed to drive the twisting motion, this section of skip rope is supported by the aforementioned support tube 80. This is preferably a stiff tube of either metal of structural plastic. The stiff tube is itself supported by the aforementioned low friction bearings 82 allowing full rotation about its own axis. This reduces the torque needed to drive this region of the skip rope assembly to very nearly zero. This structure of the support tube and bearings, provides an advantageous support for the length of fluid tubing or lumen between the guides 52 and 54. Because the support tube is free to rotate, upon rotation of the members such as 60 and 90 in FIG. 1, in other words first and second rotation mechanisms, the fluid tubing is free to either rotate with or rotate relative to the support tube.
Another characteristic of the present invention relates to the construction of the multilumen rope itself, as illustrated, for example, in FIG.5B. This may be comprised of a plurality of at least eight lumens 100B about a center lumen 102B. The center lumen 102B is straight while the other peripheral lumens wrap, such as illustrated in FIG.5B. The center lumen 102B may be an expresser tube while the lumens100B may be processing tubes. Put another way, the tube 102B may be an input tubing and tubings 100B may be output tubings. The input and output tubings may be also reversed.
It will now be apparent to those skilled in the art that other embodiments, improvements, details and uses can be made consistent with the following claims.

Claims

A combination of a multi-lumen rope, fluid retaining mechanism, a rotor (20), a support arm (50), a support tube (80) and a bearing member (82) comprising a plurality of elongated tubes the multi-lumen rope (100B; 102B) suitable for delivering one or more fluids between a first fluid retaining mechanism and a fluid receiving rotatably driven rotor (20), one end of the rope being attached to the center of the driven rotor (20), the other end of the rope being attached to the first fluid retaining mechanism, the first fluid retaining mechanism being mounted on an opposing side of the rotor (20) and such that the point of attachment of the other end of the rope is substantially coaxial with an axis (40) of the rotor (20), characterised in that, said support arm (50) is rotatable with the rotor (20), said support tube (80) can receive therethrough at least part of the distal length of the elongated tubes (100B; 102B), and wherein a guide member is provided, which is a C-shaped or S-shaped guide member (52; 54) secured to one side of said support arm (50), and said bearing member (82) rotatably supports said support tube (80) in said support arm (50).
A combination as set forth in claim 1, wherein said support arm (50) has a channel for receiving said support tube (80) and opposite recesses for receiving a pair of bearings that comprise said bearing member.
A combination as set forth in claim 1 or 2, further including another guide member secured to the other end of said support arm.
A combination as set out in claim 1 wherein said elongated tubes (100B; 102B) comprise at least one tube disposed in a spiral wrap.
A combination as set forth in claim 4, wherein said plurality of tubes include a center expresser tube and a plurality of peripheral processing tubes.
A combination as set forth in claim 4 or 5, wherein said spiral wrap is counterclockwise.
A combination as set forth in claim 4 or 5, wherein said spiral wrap is clockwise.
A combination as set forth in claim 4 or 5, wherein one end of the rope has a right hand twist and the other end of the rope has a left hand twist.
A combination as set forth in claim 8, wherein a section of the rope in the middle has no twist.
A combination as set forth in any of claims 4 to 9, wherein the rope is installed so that both ends twist up to yield maximum tortional stiffness.
A combination as set forth in claims 4 to 10, wherein the rope is installed so that both ends untwist to produce minimum restriction to fluid flow in the tubes.
A centrifuge (10) for rotating a fluid retentive housing (20) such that one or more selected materials suspended in a fluid retained within the housing are centrifuged upon rotation of the housing, said centrifuge (10) including: a first rotatable mechanism (60) having a rotation axis with the fluid retentive housing (20) being coaxially mounted on the first rotatable mechanism for co-rotation therewith; a second rotatable mechanism (90) having a rotation axis with the first and second rotatable mechanisms being coaxially interconnected for co-rotation around a common axis (40); fluid tubing (70) connected to the axis (40) of the fluid retentive housing (20) and having a distal length (72) that extends axially outwardly from the fluid retentive housing; characterized by a support arm (50) mounted to the second rotatable mechanism (90), a support tube (80) for receiving therethrough at least part of the distal length (72) of said fluid tubing (70), a guide member where said guide member is a C-shaped or S-shaped guide member (52; 54) secured to one side of said support arm (50) and a bearing member (82) for rotatably supporting said support tube (80) in said support arm, whereby upon rotation of said first and second rotation mechanisms said fluid tubing (70) is free to one of rotate with and rotate relative to said support tube (80).
A centrifuge (10) as set forth in claim 12, wherein said support arm (50) extends to either side of said first and second rotatable mechanisms.
A centrifuge (10) as set forth in claim 12, wherein said support arm (50) includes a longitudinal channel for receiving said support tube (80).
A centrifuge (10) as set forth in claim 14, wherein said support arm (50) also includes oppositely disposed recesses for receiving said bearing member.
A centrifuge (10) as set forth in claim 15, wherein said bearing member (82) comprises a pair of oppositely disposed bearings received in said recesses of said support arm (50) and for supporting opposite ends of said support tube (80).
A centrifuge (10) as set forth in claim 16, wherein said C-shaped guide member (52) is an input guide member.
A centrifuge (10) as set forth in claim 17, including an output S-shaped guide member (54) secured to an opposite end of said support arm.
A centrifuge (10) as set forth in claim 12, wherein said C-shaped guide member (52) is an input guide member.
A centrifuge (10) as set forth in claim 12, including an S-shaped output guide member (54) secured to an opposite end of said support arm.
A centrifuge (10) as set forth in claim 12, wherein said fluid tubing comprises a high durometer urethane tubing.
A centrifuge (10) as set forth in claim 12, further including another C-shaped or S-shaped guide member (52; 54) at an opposite end of said support arm.
A centrifuge (10) as set forth in claim 12, wherein said pair of guide members are each smooth, Teflon, hardcoated, aluminum members.
A centrifuge (10) as set forth in claim 12, further comprising: a frame; the first rotatable mechanism (60) having a rotation axis (40) and a first diameter, the second rotatable mechanism (90) having a rotation axis and a second diameter greater than the first diameter, the first and second rotatable mechanisms being coaxially mounted on the frame; the second rotatable mechanism (90) having an outer circumferential surface (91) engaged with a drive mechanism, the drive mechanism driving the outer circumferential surface such that the second rotatable mechanism (90) rotates at a selected rotational speed X; the first rotatable mechanism (60) being interconnected to the second rotatable mechanism (90) such that the first rotatable mechanism rotates simultaneously with the second rotatable mechanism at a rotational speed of 2X.
A centrifuge (10) as set forth in claim 24, wherein said support arm (50) has a channel for receiving said support tube (80) and opposite recesses for receiving a pair of bearings that comprise said bearing member.
A centrifuge (10) as set forth in claim 25, further including another S-shaped guide member (54) secured to the other end of said support arm.