CA1068657A - Disposable centrifugal blood processing system - Google Patents

Abstract

DISPOSABLE CENTRIFUGAL BLOOD PROCESSING SYSTEM

Herbert M. Cullis Abstract of the Disclosure A continuous flow centrifugal processing system for separating whole blood into fractional components in-cludes a centrifugal separator unit having a molded bowl-shaped outer shell dimensioned to fit within a rotatably-driven casing on an associated centrifuge apparatus. A bowl-shaped inner shell disposed within the outer shell forms therewith a thin separation channel radially spaced from the axis of ro-tation wherein fractions are separated from the whole blood under the influence of centrifugal force. A rotating seal carried on the processing chamber between ports in the chamber and the non-rotating portions of the system. The outer shell includes a relatively thin side wall portion which is inwardly biased toward a side wall portion on the inner shell when seated in the casing. A plurality of projections on the side walls limit inward deformation of the outer shell to maintain a very close concentric spacing between the shell members to facilitate rapid separation of blood flowing through the chamber.
By reason of the shell members being molded, the processing chamber can be economically produced in large quantities for disposable one-time use.

Description

~0~8~S7 ~

- This application is a divlsion of co-pending Canadian Application No. ~
258,070 filed July 29, 1976 :
Bac_~round of the Invention The present invention is directêd generally to appar-:
atus for separating or fractionating whole blood into its S various individual components, and more particularly to a dis-posable centrifugal blood separator for use in such apparatus~
Intervivos blood processing apparatus, wherein blood is taken from a live donor, passed through the apparatusr and .
then returned to the donor, has oome into wide use during re-I0 cent years.~ During passage through the appaxatus, the blood ~
may be separated or ractionated into its comp~nent parts, i.e. t ' ~ ' plasma, red blood cells, and white blood cells or platelets, and some portion of these fractions may be returned to the donor - while other portions may be selectively retained within suitable storage means.
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Various types of apparatus have been proposed ~or the~
intervivos processing of blood. One type of apparatus which has come into wide use is described in U.S. Patents 3,48~ 5 and 3,655,123. This apparatus utilizes a centrifugal separator element ln the form of a rotatably driven bowl-shaped outer shell within which a cylindrically shaped center or filler piece is suspended to form a narrow sleeve-shaped separation chamber of very precise dimensions. Fluid connections axe es- `
tablished with the chamber by means of a rotating seal, the chamber having an axially-aligned inlet port at one end for ' "' ' ~ ", ... . ,. . , ,.. ........ . . ,... ... . . . .. . .. : .. ... .

1~6865~ -admitting whole blood, and a trio of col.lection ports at the other end for removing red blood cells, white blood cells, and . .
plasma components separated during centri~ugation. The .;.
structure and operation of a rotating seal for conveying whole S blood to the chamber and fractionated blood components from the chamber is described in U.S. Patent 3,519,201.
, A major drawback of centrifugal processing units of I this type has been their high cost of manufacture. This has resulted primarily because of the very naxrow spacing which must be main*ained between the inner wall o the outer shell and the outer wall of the central filler in order to achieve :.
efficient separation of the blood components during the very.
limited transit time in which the blood is a~tually in the pro- ..
cessing chamber. Typically, a spacing of 1.~ to l.S mms is lS necessary for typical transit times of approximately three minutes. This dimenslon must be maintained with a.high degree 'l of concentricity lf mixing of the recovered f ractions is to be ``~ avoided. As a result, the outer shell has heretofore been formed with thick side walls to prevent any variation of the separa.tion ` ` 20 channel width during operation o~ the apparatus.
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The need for thick side walls has made it heretofore impractical to mold the inner and outer shells, since the desired :: :
thicknesses could not be molded with the necessary precision.
Instead, such shells have been extruded and then individually machined, making the cost of manufacture too high for the ~ .:

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disposable single-use favored for avoiding contamination.
SUMMARY OF THE INVENTION
In one aspect the present application, which is a division of aforementioned Canadian Application No. 2587070, is ~ .
concerned with the provision of a centrifugal blood processing ..
system compriæing, in combination: a stationary base; a rotor drive assembly rotatably mounted to said base for rotation along a pre-determined axis; a rotor assembly including at least one blood processing chamber, said rotor assembly being rotatably mounted with respect to said base for rotation along said axis; means including a flexible umbilical cable segment for establishing fluid communication with sald blood processing chamber, one end of said cabIe segment being fixed with respect to said base along said axis at one side of said rotor assembly, the other end of said cable segment being attached on said axis in rotationally locked engagement - to said rotor assembly; and drive means for rotating said rotor assembly and said rotor drive assembly ln the same direction with a speed ratio of 2:1 to prevent the umbilical cable from becoming :. completely twisted during rotation of said rotor.
In another aspect the present application is concerned with the provision of a centrifugal blood processing apparatus for ~ ~ use in conjunction with a flow system including at least one blood ~ processing chamber and a flexible umbilical cable segment having a :.
plurality of integral passageways for establishing fluid communic- .:;
.~ ation with said blood processing chamber, said apparatus comprising, :
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.in combination: a stationary base; a rotor drive assembly rotatably .
mounted to said base for rotation along a predetermined axis; a rotor assembly including means for receiving said blood processing .
chamber, said rotor assembly being rotatably mounted with respect ..
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to said base for rotation along said axis; means including a stationary support member for anchoring one end of said cable at one side of said rotor assembly at a fixed position along said axis with respect to said base, the other end of said cable segment extending to said rotor assembly and being rotatably locked thereto . along said axis; guide means for causing said umbilical cable to rotste about said axis with said rotor drive assembly; and drive means for rotating said rotor assembly and said rotor drive assembly in the same direction about said axis with a speed ratio of 2:1 to :~
prevent said umbilical cable from becoming completely twisted during operation of the apparatus.
In a further particular aspect the present application lS
concerned with the provision of the method of centrifugally pro-. cessing biological fluid with reduced risk of contamination of .. ~
the fluids of the outside environment using a closed leakproof envelope which envelope includes an umbilical having input and output at one side thereof and defining passageways therethrough, which umbilical includes a flexible segment which is capable of repeated axial twisting and untwisting, and which envelope also : .1 , .:., j~ 20 includes at least one processing chamber co~nected at the o~therside of the umbilical which chamber is in communication with the passageways thereof, comprising the steps of: taking the envelope and positioning the umbilical at the one side thereof at one . - . .
.. position on an axis while forming the flexible umbilical into a ~ loop which extends outward from the axis and returns at its other .;~ side to a displaced second position on the axis while supporting : the connected processing chambers at a radially displaced position from the axis, orbiting the loop so formed at a first rotational speed about the axis and orbiting the processing chamber so positioned ,;
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about the axis in the same direction as the loop at the same time at twice the rotational speed of the loop while allowing the umbilical to twist and untwist axially so that the envelope does not bind, while supplying the biological fluids to the input and passing these fluids through the passageways to the chambers where they are sub~ect to a centrifugal force and processed.
BRIEF DESCRIPTION OF THE DRAWINGS
The features of the present invention which are believed to be novel are set forth with particularity in the appended claims.
The invention, together with the further objects and advantag~s thereof, may best be understood by reference to the following .
description taken in conjunction with the accompanying drawings, in the several figures of which like reference numerals identify like elements, and in which:
Figure 1 is a perspective view of a centrifugal blood ! separator constructed in accordance with the invention partially broken away to show the internal construction thereof.
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Flgure 2 is an enlarged cross-sectional view of the blood separator installed in a rotating seal type centrifugation apparatus.
~ F~gure 2a is an enlarged cross-sectional view of the rotating seal assembly utilized in the apparatus shown in Figure 2.
Figure 3 is an enlarged cross-sectional view of the `~ downline end of the processing channel illustrating the distribution of fractionated components therein.

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Figure 4 is a diagrammatic representation of the flow system utilized in conjunction with the centriugal blood separator of the invention.
Figure 5 is a cross-sect1onal view of the centrifugal blood installed within a seal-less centrifugation apparatus~
Description of the Preferred Emb d _ent Referring to the Figures, and particularly to Figure l, a centrifugal blood sepaxator lO constructed in accordance with the invention ~includes a bowl-shaped outer sheIl ll dimensioned to fit within a similarly shaped recess in a ro-tatably driven casing (not shown in Figure l~. A bowl-shaped inner shell 12 is disposed within the outer shell and fonms therewith a centrifugal processing chamber 13 within which i - fractionation of whole blood takes place during rotation of .
lS the separator assembly. The rims-of the two bowl-shaped shells are joined by cemented tongue-and-groove attachments to a flat cover member 14 which includes four red blood cell (RBC) collection ports 15 arxanged in a first ring, and four white blood cell twBc) collection ports 16 arranged at equal inter~als : 20 in a second rLng concentric with the first ring but of lesser diameter. The cover member also includes a plurality of aper-tures 17 at its center for establishing fluid communication with .. . .
a ro*ating seal (not shown in ~igure l~ in a manner to be described presently. Each of the four collection ports lS is .
connected to a length of tubing 18 which extends through an , :
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~- ~L06~3657 . . . aperture 19 in cover member 14 and into the interior of the bowl-shaped inner shell 12. Similarly, each of the collection :
ports 16 is connected to a length of tubing 20 which extends through an aperture 21 and into the interior of the inner shell member.
Referring to E'igure 2, wherein the centrifugal .
separator unit is shown in conjunction with a rotating-seal type centrifugation apparatus, the outer shell 11 of the separator is seated in a rotatably driven casing. The outer .. :
shell includes a thin upstanding cylindrical side wall portion 23 which terminates at its upward or downline end in an outwardly and then upwardly directed.rim portion 24, and at its downwaxd .:
or upline end in an angular portion 25 joining a flat bottom .
wall portion 26. Similarly, the inside shell.12 includes a .
.; -15 thin upstanding cylindrical side wall portion 27, an inwardly : and then upwardly directed downline portion 28, and an angular portion 29 joining a flat bottom wall portion 30. ~he interior surfaces of the side wall portions 23 and 27 together define a separation channel 31 within processing chamber 13 within which :.
~ 20 RBC, WBC and plasma components are separated from the whole :.::
: blood as it flows through the channel under the influence of ..
a centrifugal force field. The rim portions 24 and 28 together :. :
define a region in chamber 13 of increased width wherein the blood components separated within channel 31 accumulate prior :~
to withdrawal through collection ports 15 and 16. ~.

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--` ~L0686~;i7 - -~ An additional collection port 32 is provided in the , rim portion 28 o~ inner shell 12 for the purpose of withdrawing pla ma as it accumulates in chamber 13. Tpis collection port 1s connected by a length of tubing 33 to a passageway 17a in top plate 14. Similarly, tubing 18 connects to a passageway 17b and tubing 20 connects to a passageway 17c in top plate 14.
To prbvide means for admitting whole blood into separation channel 31 the inner shell 12 i5 provided with an inlet por~
34 along the~axis of rotation of casing 22. This port is connected by a tubing segment 35 to a passageway 17d in cover member 14. Additional apertures 36 may be provided through ::
the bottom wall poxtions 26 and 30 of the inner and outer shells to facilitate installation of the separator 10 in a seal-less type centrifugal apparatus in a manner to be described presently.
To provide fluid communicati~n between the inlet and collection ports and the non-rotating portions of the flow ; system associated with the separator a rotating seal assembly : 40 is provided on top plate 14 alonq the axis o rotation of casing 22. This seal assembly/ which may be conventional in .
construction and operation, is mounted to top plate 14 b~ means ..
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of suitable fastening devices such as bolts 41. Referring to Figure 2a, the rotating seal assembly consists of a rotating : member 43 having a plurality of ring-shaped recesses 44 ., .
therein and a stationary member 45 having a plurality of communicating ring-shaped recesses 46 therein. Individual . : .
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~ -- 106~365~7 -lands 47 are provided between xespective ones of the recesses to maintain fluid isolation and additional irrigation and/or lubrication flow systems may be provided for improved operation ; in a manner well known to the art.
- In practice, two passagewa~s are provided in top plate 14 ~or each ring-shaped recess associated with a frac-tional component, and each of these passageways may in turn be connected by an appropriate Y-connector and appropriate lengths o~ connecting tubing to respective ones o the four collection ports associated wlth that fraction. These connections ha~e not been shown in Figure 2 for the sake of clarity.
The upper non-rotating portion 45 of the rotating seal assembly 40 is held in a stationary non-rotating position ` - in compression-engagement wlth the lower rotating portion 43 by means of a retainlng arm 48 mounted on the frame of the ; centrifugation apparatus. The lower rotating portion of the .
seal may consist of a polished ceramic disc attached to member .~ . . .. .
14 by means o~ concentric silastic O-rings which establish :, .
~ fluid communication between recesses 44 and appropriate : ~ :
~ ones of passageways 1% The upper stationary portio~ of the seal is formed of stainless steel lapped to insure perfect contact with the ceramic disc. Each of the ring~shaped recesses 46 thereon is connected by a passageway to a tubing port on the top of the disc.

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Referring to Figure 4, the RBC outlet port is connected ' ` : ' ' ~ -8- ~

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by a tubing segment 50 to a peristaltic pump 51, the WBC outlet port is connected by a tubing segment 5Z to a peristaltic pump 53, and the plasma outlet port is connected by a tubing segment 54 to a peristaltic pump 55. Whole blood is supplied to the inlet port by a tubing segment 56, to which acid citrate dextrose ~ACD) and Heparin are introduced through respective tubing segments 57 and 58 and a peristaltic pump 59. Saline is supplied to the rotating seal for isolation purposes through . a tubing segment 60 and exhausted through a tubing segment 61.
: lO Saline is supplied to the seal for lubrication purposes by means of a tubing segment 62 and a peristaltic pump 63.
The white blood cells, red blood cells and plasma derived by the system may be pumped to respective collection bags for storage or may ~e returned to the donor as required.
Various safety devices may be incorporated into the system to guard against leakage of air or undue temperature rise, or . the occlusion of a vein in the donor.
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. . Casing 22 is mounted on a drive shaft 64 which in ~ turn is rotatably driven by means of a motor 65. In practice, this drive arrangement is designed and constructed to provide a very high degree of concentricity in the rotation of casing 22 to insure efficient operation of the separati~n process and efficient operation of the seal assembly 40.
In operation, casing 22 is rotated at approximately 800 rpm to establish a centrifugal force field across separation .'~ ' ' .
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~06~3657 channe1 31. The flow path is ne~t primed with sterile saline ' ' ' ` solution and all air bubbles are removed by back-f1ushing the system through the WBC peristaltic pump 53. Whole blood is then admitted through tubing 56, rotating seal assembly 40, - "' and tubing segment 35 to inlet port 34. The whole blood flows radially outwardly wi'thin chamber 13 and up~ardly through separation channel 31, The centrTfuge speed is now adjusted tp achieve separation of the RBC, WBC and plasma components in the manner Tllustrated in Figure 3. Separation begins as the ' 10 blood flows up the side of the bowl toward the coilection ports, the blood eventually separat7ng into three concentric bands, with `
the dense red blood cells outermost, the less-dense white blood cells, or buffy coat, at an intermediate radius and the least dense plasma at the shortest radius. Platelets are generally dis- ~ ' : .
tributed among all three regions but can be concentrated somewhat by varying the centrifuge speed. Collection ports 15, 16 and 32 .
remove the components from processing chamber 13 for coltection ar return to the donor as desired.
Typically, the f!ow'rate of the whole blood in chamber ,, 13 is such that the residence time of the blood in the chamber is ` ~' ' about three minutes To insure that separation oF the btood components will take place within this relatively short period of time it is necessary that the width of the separation chonnel 31 be very small, typically in the order of 1~5 mm or less, To obtain efficient separation of the blood components '~

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;`` ~06~6sq this dimension must be maintained with a high degree of con-centricity so that the components as they separate will flow upwardly to the collection area at the upper end of chamber 13 To insure that the desired separation channel width is maintained with ths desired degree of concentricity, the o~ter and/or inner shell members are provided, in accordance with the invention, with a plurality of inwardly-projecting integrally-molded spacin~ bosses 60 which bear against their opposing shell surface to maintain accurate spacing. To insure that these bosses will in fact be determinative of the inter-ielement spacing, the outer shell 11 is dimensioned such that when-the separator unit 10 is sea~ed in casing 22 the side walls -of the outer shell are caused to deform inwardly to a slight extent. This deformation is sufficient to bring the spacing bosses 60 into engagement with their opposing wall surfaces and assure that the desired spacing is es~ablished and maintained ~ . . . . . .
To facilitate insertion of the separatar unit in casing 22 the outer shell is preferably formed with a slight inward taper, , ~ typically in the order of one degreet\and the inner wa~ll o~
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; ~ 20 ~ casing 22 is formed with a complimentarily taper.
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~ The inner and outer shells are preferably molded o~
a polycarbonate plastic such as Lexan (a trademark of General Plastic Corporation) by means of conventional molding techniques.
The sidewalls 23 and 27 of these shells may have a thickness of 0.125 inch to obtain the desired inward deformation when the : ' ' ' ": ' - : ~ . ,:.

1at686S7 .
separator is seated in casing 22. In a representative application, the separator 10 is formed with an outside diameter of approximately 6 inches and a height of approximately 4 inches~ With a proc-essing channel 31 1.5 mm wide, the processing chamber 13 has a volume of approximately 140 ml.
Once the various lengths of tubing have been installed during manufacture of the separator unit lQ the volume enclosed within the inner shell 12 may be filled with a foam material 66 to prevent accumulation of significant quantities of fluid within the chamber. This is a safety feature to insure that any leakage will be immediately evident to the operator and will not accumulate within the rotating bowl assembly.
Referring to Figure 5, the centrifugal separator unit of the invention may also be utilized in conjuaction with a seal-less centrifugation apparatus such as that described and claimed in co-pending Canadian Application No. 247,878 filed March 15, 1976, and assigned to the present assignee. Basically, this centri-fugation apparatus includes a rotor-drive assembly 70 to which a ", ~ rotor assembly 71 is journaled by means of a hollow support shaft 72. The rotor drive a=sembly 70 is journalod to a stationary hub assembly 73 by means of a vertical drive shaft 74, and includes a guide sleeve 75.
The centrifugal processing chamber 10 of the invontion is seated on the rotor assembly 71. Fluid communication is . ~ .

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established between the separator unit, which rotates with the rotor assembly 71, and the non~rotating portion of the flow system~
which may be identical to that shown in Figure 4 except for the omission of the rotating seal member 40, by means of a four channel umbllical cable 76 which extends from a central location along the axis of rotation of the separator unit downwardly through the center of drive shaft 72, radially outwardly through guide sleeve 75 and upwardly to a fixed axially-aligned position establised by a support arm 77. As desc*ibed in the previously 10 identified co-pending Canadian Application No. 247,878, this routing of the umbilical cable 76, together with the rotor assembly 71 and rotor drive assembly 70 being driven in the same direction wlth a epeed ratio of 2:1, establishes fluid communication with centrifugal separator unit 10 without the cable becoming twisted.
Instead, the umbical cable is subjected only to flexing, or repeated partial twists about its axis through angles not in excess of 180 degrees, as the rotor assembly 71 rotates.
To obtain the desired 2:1 speed ratio between the rotor and rotor drive assembly two pairs of idler pulleys 78 are mounted ; 20 on rotor drive assembly 70. A drive belt 79 is routed over these pulleys and around a stationary ring-type pulley 80 mounted on hub 73 at one end, ~and around a rotor drive pulley 81 carried on the bottom end of the rotor drive shaft 72 at its other end. As the rotor drivs asssmbly 70 is rotated :: ' '' ' ' :' .

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:' , ~:1168657 clockwise by means of a motor ~not shown) driving drive shaft 74, drive belt 79 establishes a clockwise rotation of rotor assembly 71. Assuming that stationary pulley 80 and rotor drive pulley 81 have the same diameter, the rotational speed S o~ rotor assembly 71 will be exactly twice that of rotor drive assembly 70, by reason of the combined efect of the direct 1:1 drive relationship established by pulleys 80 and 81 and the planetary motion of idler pulleys 78 about the rotational axis of rotor assembly 71.
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In order that the centrifugal separator unit 10 can be seatsd in rotor assembly 71 the tubing se~ments 1~, 20 and 33 associated with collection ports lS, 16 and 32 are routed through the center of the separator unit and down through aper-- tures 36 in the bottom walls o the inner and outer shell .. . .
mambers. A casing 82, which may be similar to casing 22 in all respects except for the provision of passageways 83 in its bottom wall for accommodating the connecting conduit segments, .
; is mounted on rotor assembly 71 to receive the centrifugal ~ separator unit. As with the previously described rotating seal ,:
embodiment, the wall of the outer shell is compressed by casing :
; -82 to obtain a separation channel 31 having a high degree of " . ;
concentricity. The individual connecting tubing segments after passing through passageways 83 are joined into umbilical cable 76. ;
It is contemplated that the centrifugal separator `'' , '' " ~

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,; : , ~.068~;57 unit 10 when intended for use in a ~eal-less centrifugation apparatos such as that shown in Figure 5 would be manufactured as a single integral disposable unit in which umbilical cable 76 is.included. To install this unit in the apparatus the free end of the umbilical cable could be threaded downwardly through the hollow rotor support shaft 72 and then radiall~
outw~rdly and upwardly through sleeve 75 to support arm 77.
The free end of the cable would then be pulled thxough until the separator unit was seated in casing 82. After ùse, the entire assembly would be removed from the apparatus and dispo~ed of.
, A centrifugal blood separator unit has been shown - and described which provides efficient processing of blood ' into its constituent components. The separator unit can be : 15 economically formed by known molding techniques, and by reason., of its low cost of manufacture, is ideally suited for d.isposable ~ , . .
`. one-time use situations whereln the dangers of contamination : .
: to the donor f~om prior uses are completely avoided. .. :
.. ~ While particular embodiments of the invention have ;~ 20 been shown and descri~ed, it will be obvious to those skille~
:
. in the art that changes and modifications may be made without departing from the invention in its broader aspects, and,there- .:
! ~ ' ~ :~ fore, the aim in the appended claims is to cover all such :: .
. changes and modifications as fall within the true spirit and scope of the invention.
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As is best shown in Fig. 3, a concentric lip i6L is ~rovided having an inner surface atigned with the outer side of the white blood cell ~ollection ports 16, and the adjacent bottom surface of the cover member 14 is provided with a concentrlcgroove 16G into which the porrs 16 open. The provision of this groove and lip has resulted in experimentally verified better separation of the red blood cells from the collected white blood cells.
It has been found in one bowl that only four spacer units 60 need to be employed and that the spacer flange between the inner and outer shetls at 36 serves to not only fix the horizontal wall (bottom to top) spacing but also, to a significant degree, to fi~ the side wall spacir~. In one embodiment only four spacers 60 were used successfully. These were positioned near the upper surEace at equal spacingaround the unit. One experimental bowl which was constructed in accordance with the present invention was made of polycarbonate molded in four parts and had an overall height of approximately four inches and a diameter of approximately six and one-eighth inches. This particular unit had a fluid capacity of only 143 ml which : compares favorably with the prior art bowls of this type.
The shells 11 and 12 were of approximately 1/8 inch thickness and main-tained a spacing of 0. 050 inches. The outer shell? although reasonably rigid for ~., .
handling purposes, was slig~ltly out-of-round and under the increased forces of centrifugation mig~ht have deformed even more. However, with a true round casing 22, and of stainless steelj the outer shell was upon insertion caused to go into a true : , - round and concentric shape.
It should be noted that the four motded ports of the bowl 10 of the two em-;; ` bodiment (Fig. 1- 2 and Fig. 5) are identical and may be adaptable to elther conEigu-ration. The present invention allows for these ports to be mamlfactured with greater '.` ~i ;.' ', - i~06865'7 dimensional tolerances than is the case with prior art permanent type bowls and yet achie~re good results.
It is contemplated that the disposable bowls of the present invention of the Fig. 1- 2 type could be easily retrofitted to existing commercial machines such as the CELLTRIFUGE~)separator unit made by the American Instrument Company division of Travenol Laboratorles, Inc. 9 by the securing of an appropriate casing in the unit. Of course, slmilar casings could be used to enable o~er brands of suc~
machines to be similarly retrofitted.
Although polycarbonate is the plastic presently preferred in making the outer shell and other of the blood contacting portsr other plastic materials may also be used, such as methyl methacrylate, styrene-acrylonitrile, acrylic, styrene, or acrylonitrile. While molding is the presently prefexred metho~ of manufacture, it is also possible to form the shells by vacuum forming or casting.
Also, although the inner shell is depicted as hollow and later preferably filled with for~n, thë term "inner shell'` should be understood in the claims to include solid units.

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Claims (18)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY OR
PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A centrifugal blood processing system comprising, in combination:
a stationary base;
a rotor drive assembly rotatably mounted to said base for rotation along a predetermined axis;
a rotor assembly including at least one blood processing chamber, said rotor assembly being rotatably mounted with respect to said base for rotation along said axis;
means including a flexible umbilical cable segment for establishing fluid communication with said blood processing chamber, one end of said cable segment being fixed with respect to said base along said axis at one side of said rotor assembly, the other end of said cable segment being attached on said axis in rotationally locked engagement to said rotor assembly; and drive means for rotating said rotor assembly and said rotor drive assembly in the same direction with a speed ratio of 2:1 to prevent the umbilical cable from becoming completely twisted during rotation of said rotor.

2. A blood processing system as defined in Claim 1 wherein said blood processing chamber is on said one side of said rotor assembly, said rotor assembly is rotatably mounted to said rotor drive assembly by means of a drive shaft having an axially-extending aperture, and said umbilical cable segment extends through said aperture and into communication with said blood processing chamber.

3. A blood processing system as defined in Claim 2 wherein said rotor drive assembly is rotatably mounted to said base by means of a support shaft axially-aligned with said axis of rotation, and said base includes a stationary pulley, and wherein said drive means include a motor for driving said support shaft, and planetary drive means carried on said rotor drive assembly and coupled to said stationary pulley and said drive shaft for driving said rotor assembly.

4. A blood processing system as defined in Claim 1 including guide means for said umbilical cable which include a guide member carried on said rotor drive assembly for engaging said cable.

5. A blood processing system as defined in Claim 4 wherein said guide member is tubular and said umbilical cable passes therethrough.

6. A blood processing system as defined in Claim 5 wherein said tubular guide member is planetarily driven to minimize friction between it and said cable.

7. A blood processing system as defined in Claim 4 which further includes a stationary support member for supporting one end of said umbilical cable segment substantially along said axis on one side of said rotor assembly and wherein said guide member com-prises a sleeve extending from a location on the other side of said rotor assembly to a location adjacent said support member.

8. A blood processing system as defined in Claim 1 wherein said rotor assembly includes a plurality of fluid processing chambers, and wherein said umbilical cable includes at least one passageway for each chamber.

9. A blood processing system as defined in Claim 1 which further includes a stationary support member for supporting one end of said umbilical cable segment substantially on said axis on said one side of said rotor assembly.

10. A centrifugal blood processing apparatus for use in conjunction with a flow system including at least one blood pro-cessing chamber and a flexible umbilical cable segment having a plurality of integral passageways for establishing fluid communic-ation with said blood processing chamber, said apparatus comprising, in combination:
a stationary base;
a rotor drive assembly rotatably mounted to said base for rotation along a predetermined axis;
a rotor assembly including means for receiving said blood processing chamber, said rotor assembly being rotatably mounted with respect to said base for rotation along said axis;
means including a stationary support member for anchoring one end of said cable at one side of said rotor assembly at a fixed position along said axis with respect to said base, the other end of said cable segment extending to said rotor assembly and being rotatably locked thereto along said axis;
guide means for causing said umbilical cable to rotate about said axis with said rotor drive assembly; and drive means for rotating said rotor assembly and said rotor drive assembly in the same direction about said axis with a speed ratio of 2:1 to prevent said umbilical cable from becoming completely twisted during operation of the apparatus.

11. A blood processing apparatus as defined in Claim 10 wherein said blood processing chamber is on said one side of said rotor assembly, said rotor assembly is rotatably mounted to said rotor drive assembly by means of a drive shaft having an axially-extending aperture, and said umbilical cable segment extends through said aperture, and into communication with said blood processing chamber.

12. A blood processing apparatus as defined in Claim 10 wherein said rotor drive assembly is rotatably mounted to said base by means of a support shaft axially-aligned with said axis of rotation, and said base includes a stationary pulley, and wherein said drive means include a motor for driving said support shaft, and planetary drive means carried on said rotor drive assembly and coupled to said stationary pulley and said drive shaft for driving said rotor assembly.

13. A blood processing apparatus as defined in Claim 10 wherein said guide means for said umbilical cable include a guide member carried on said rotor drive assembly for engaging said cable.

14. A blood processing apparatus as defined in Claim 13 wherein said guide member is tubular and said umbilical cable passes therethrough.

15. A blood processing apparatus as defined in Claim 14 wherein said tubular guide member is planetarily driven to minimize friction between it and said cable.

16. A blood processing apparatus as defined in Claim 10 wherein said guide means comprises a sleeve extending from said fixed position along said axis to a location adjacent the other side of said rotor assembly.

17. The method of centrifugally processing biological fluid with reduced risk of contamination of the fluids of the outside environment using a closed leakproof envelope which envelope in-cludes an umbilical having input and output at one side thereof and defining passageways therethrough, which umbilical includes a flexible segment which is capable of repeated axial twisting and untwisting, and which envelope also includes at least one processing chamber connected at the other side of the umbilical which chamber is in communication with the passageways thereof, comprising the steps of:
taking the envelope and positioning the umbilical at the one side thereof at one position on an axis while forming the flexible umbilical into a loop which extends outward from the axis and returns at its other side to a displaced second position on the axis while supporting the connected processing chambers at a radially displaced position from the axis, orbiting the loop so formed at a first rotational speed about the axis and orbiting the processing chamber so positioned about the axis in the same direction as the loop at the same time at twice the rotational speed of the loop while allowing the umbilical to twist and untwist axially so that the envelope does not bind, while supplying the biological fluids to the input and passing these fluids through the passageways to the chambers where they are subject to a centrifugal force and processed.

18. The method of Claim 17 wherein the biological fluids are thawed once-frozen blood cells including a preservative, and wherein a wash fluid is also supplied to wash the preservative from the cells.