IL31768A - Assembly and process for centrifugal separation - Google Patents

Description

ASSEMBLY AND PROCESS FOR. CENTRIFUGAL SEPARATION The present invention relates to centrifug¾ ion. More particularly the invention relates to a washing centrifuge assembly and to a process for material separation by centrifugation. Specifically the invention relates to an assembly, including a centrifuge, and a process for washing particles such as red blood cells.

Heretofore it has been known to wash particles by using centrifuging means. The principles generally relating to such particle washing have been effectively applied in washing red blood cells, particularly for reconstitution following treatment with such reagents as glycerol, polyvinyl pyrrolidone and the like for cell protection. Two heretofore known systems for reconstituting preserved red blood cells by the aforestated technique have gained significant practical success. One thereof embodies the teachings of U.S. Patent 2,906,453. The other thereof embodies the teachings of U.S. Patent 3,347,454 and is assigned to the assignor of the present application.

While the apparatus of both prior systems are practical for washing preserved red blood cells in single batches, neither they, nor any of heretofore known means, is adequate effectively and efficiently for washing a plurality of batches of preserved red blood cells simultaneously. That is to say, while simultaneous multi-batch washing could be practiced in accordance with heretofore known teachings, thereto attendant inefficiencies would increase costs inordinately. In consequence, prior e o w shin of red cells in more has been neither practical nor conventionally pract9ked, except experimentally. The inefficiencies result from differential resistance to flow of wash fluid generated in material comprising the batches simultaneously being processed. The phenomenon is such that wash fluid in ever increasing volume flows through one of the batches while it increasingly bypasses any other.

The present invention provides a washing centrifuge assembly having a centrifuge rotor and a plurality of containers supported from said centrifuge rotor for rotation therewith, charging means for moving influent into each of said containers under an independent pressure head as said rotor spins for washing material contained therein, and discharging means for collecting effluent from each of said containers in a volume corresponding to influent moved into said containers.

The present invention also provides a centrifugal clamp assembly comprising a rotatable body, a clamp mechanism co-rotational with and arranged for radial movement from said body between clamping and release positions, and means for biasing said clamping means toward one of said positions and releasing said clamping means for movement to the other position upon generation of a centrifugal force of a magnitude adequate to overcome biasing force.

The present invention also provides a bearing mechanism for an assembly having a stator and a rotor arranged for rotation with a member disposed about . said assembl , said mechanism comprising a mounting band having a retainer carried from a medial portion of said ban for releasably holding said stator and responsive to stresses imparted to said stator during rotation of said member for movement longitudinally of said band .

The present invention further provides a washing centrifuge assembly having a first rotor, container means co-rotationally supported from said first rotor, charging means for moving influent into said contains r means as said first rotor spins, discharging means for receiving effluent from said container means during movement of and in substantially the same volume as influent moved, passaged means arranged in fluid association with said charging means and discharging means for introducing influent into and removing effluent from said container means, a combination comprising a body co-rotationally secured to said first rotor and a disposable distributor-collector removably mounted in said body and arranged medially of said passaged means for transferring influent to and effluent from said container means while said first rotor is spinning.

The present invention still further provides a a process for material separation by centrifugation during which a first material is removed from a second material by a wash fluid which is first pissed through the second material and therefrom removed with first material as spent fluid, including the step of passing the wash fluid under an independent pressure head into f a luralit of batches of said second material The foregoing and other objects of the invention will become more apparent upon consideration of the following description and appended claims, when considered in conjunction with the accompanying drawings wherein the same reference character or numeral refers to like or corresponding parts throughout the several views .

On the drawings: Fig. 1 is a fragment of a vertical sectional view through a centrifuge assembly embodying the present invention, some parts being shown in elevation and other parts broken away, a pair of containers being shown at an angle 90° from actual aspect and in a nonspinning condition.

Fig. 2 is a flow scheme of said assembly, the containers being shown in a spinning condition.

Fig. 3 is a top plan view of a distributor-collector comprising said assembly.

Fig. 4 is a vertical sectional view according to the line 4—4 of Fig. 3.

Fig. 5 is a vertical sectional view according to the line 5—5 of Fig. 3.

Fig. 6 is a horizontal sectional view according to the line 6—6 of Fig. 4.

Fig. 7 is a top plan view of an assembly control box, its cover having been omitted.

Fig. 8 is a view according to the line 8—8 Fig. 9 is a side elevational view of fluid control means comprising said assembly, a pair of clamping members being shown abnormally in opposite conditions.

Fig. 10 is a view according to the broken section line - - 10 of Fig. 9.

Fig. 11 is a view according to the line 11 - - 11 of Fig. 1 , a medial part being broken away.

Fig. 12 is a scheme of wiring for said assembly, Referring now more particularly to Fig. 1 , there is shown a washing centrifuge assembly 15 comprised of a housing or outer shell 17 only an upper portion of which is shown Within chamber 19 of shell 1 7 a centrifuge rotor 21 is concentrically disposed for rotation. Rotor 21 has a hub 25 which is mounted co-rotationally with a driven spindle 27, the. latter member being suitably connected to prime mover means (not shown) . A plurality of radial members 26 (only two of which are shown) project outwardly from hub 25.

A plurality of arms 29, arranged in parallel pairs, project eccentrically from adjoining of members 26. A. pin 33 which is circular in cross section extends through each of arms 29 for projection from opposite arm faces 31. Adjoining projections of .pairs of pins 33 are engaged by opposed pairs of arcuate shoulders 35 of plurality (herein shown as a pair) of receptacles 23 and 24 for swinging support of said receptacles radially from rotor 21. Apart from evident structural variation, ,said receptacles may be constructed according to co-pending application Serial No. 672, 125, assigned to the assignee of the present application.

Container means com risin a luralit of containers 37 and \ are disposed in receptacles 23 and 24, respectively, in a manner such that each container is supported from said rotor for rotation therewith. Material to be processed, herein shown as particles 36 such as preserved red blood cells, is divided into a plurality of batches which may be of equal size, and held in containers 37 and 38 for spinning for centrifugation simultaneously with rotation of rotor 21 . The invention, however, is not limited to washing simultaneously only one pair of batches. More can be washed simultaneously. Nor is the invention limited to washing particles, inasmuch as washing of materials in other physical forms is also comprehended.

In the illustrated embodiment, an inverted cone-shaped base provides a seat 39 in each of the receptacles 23 and 24 for an associated of containers 37 and 38. A cap 41 for each of I receptacles 23 and 24 has a pair of bores through which an influent duct 43 and an effluent duct 45 extend for fluid circulation through each of said containers. The parts are proportioned so that a flange 47 on each of said caps will snugly seat against a rim 49 of a corresponding receptacle as a result of centrifugal force when the parts assum e the relationship shown in Fig. 2. However, when receptacles 23 and 24 are in the condition of Fig. 1 the normal pressure under which each container is filled with its material to be washed may hold each flange 47 spaced from associated rim 49.

Fluid control means responsive to centrifugal force comprises a centrifugal clamp assembly generally designated 51 (Figs . 1 , 9 and 10) which is secured by fasteners such as screws 53 to the top of hub 25 for co-rotation with rotor 21.

Said fluid control means has a first condition. in which ducts 43 and 38 and a second condition in which said ducts are open for flow into and out of said containers . To that end, clamp assembly 51 comprises a body 55 having a plurality of wells 56 and 57 which are herein shown . of like profile and disposed to correspond with the disposition of containers 37 and 38, herein shown as being in diametric opposition. Clamping means comprising a clamping mechanism 58 associated with each of containers 37 and 38 is disposed in each of wells 56 and 57, respectively. A block 59 comprises each clamp mechanism 58 and is proportioned to slide centrally and outwardly within the limits of its associated well along a floor 60 defining such well. A cover 93 (Fig. 9) suitably removably held on body 55 closes wells 56 and 57 from above to trap in each thereof an associated block 59.

Each block 59 has a plurality (herein shown as two) of outwardly opening, horizontally spaced apart bores 61 and 62 which accommodate spring means comprising a pair of compression springs 63 and 64, respectively. The outer ends of each pair of the latter members bear against the inner surface 65 of an associated of outer sidewalls 68 and 70 respectively defining wells 56 and 57 for biasing each block inwardly or centrally. Each block 59 carries>a generally T-shaped clamp member 67 which is secured thereto by a suitable fastener such as a screw 69. The stem 71 of each clamp member comprises a radial arm which is slideably arranged for radial extension in a slot 73 in body 55, said slots fashioned so that wells 56 and 57 open through sidewalls 68 and 70. Each clamp member 67 also comprises a pair of clamping extensions 75 and 76 integral with, and projecting horizontally in opposite directions pair of springs 63 and 64 its clamping extensions are urged toward an adjoining of sidewalls 68 and 70, as illustrated to the right of Figs. 9 and 10. Said springs, however, are tensioned so that under centrifugal force generated when receptacles 23 and 24 have assumed the extreme position of Fig. 2, its block 59 will be thrown outwardly to the outer limits of its recess 57 thereby causing projection of corresponding clamping extensions 75 and 76 from the body 55, as illustrated to the left of Figs . 9 and 10. It is appreciated that all of the clamping mechanisms 58 simultaneously will assume the condition shown either to the right or to the left of Figs . 9 and 10; and that the showing of both conditions in each view is solely for the purpose of illustrating alternate extremes, which normally will not be present simultaneously, Each pair of extensions 75 and 76 is fashioned to generate a pair of recesses or pockets 77 and 78 through which influent and effluent ducts 43 and 45 of an associated of containers 37 and 38 project. Each pair of said recesses is proportioned so that when an associated clamp member 67 is in its first condition, as shown to the right of Figs. 9 and 10, flow . in corresponding ducts 43 and 45 will be clamped shut. Whereas, when such clamp member is in its second condition, illustrated to the left of Figs. 9 and 10, said last mentioned ducts will be undamped to perm it unimpaired flow therethrough.

To facilitate clamping, each of sides 68 and 70 has a pair of horizontal elevations 81 and 83 which project in opposite directions from an associated slot 73. At its outer end each of extensions 75 and 76 has a pair of enlarged ears 85 and 87 which are associated in a U-shape and proportioned for engagement about associated of for clamping corresponding ducts 43 and 45.

Distributor means or a fluid handling mechanism comprising a distributor- collector 89 controls flow of fresh influent or wash fluid to and spent effluent or waste from the material contained in containers 37 and 38. In terms of the influent, distr ibutor-collector 89 is disposed upstream of clamp assembly 51 from which it projects upwardly. The distributor- collector comprises-relatively rotatable first and second parts, being a cup-shaped rotor 97 and a therein concentrically associated cylindrical stator 105 (Fig. 4) .

A male component 95 (Figs. 1 , 4 and 5) carried from the lower wall 99 of rotor 97 is removably keyed or snugly engaged in an opening or hole 91 (Fig. 10) formed in body 55 for transmission of torque of rotor 21 to rotor 97 for co- rotation of said rotors . Rotor 97 has an upwardly extending cylindrical sidewall 107 which defines an upper opening 108. The latter is closed by a cap 101 having an aperture 109 and secured to the top of sidewall 107 by fasteners such as screws 103, only one of which is numbered in Fig. 3.

The outside diameter of stator 105 is less than the inside diameter of rotor 97 by reason of which a space 113 is formed about said stator, said space being closed at the top and bottom by cap 101 and wall 99, respectively. Said stator has a lower end portion 106 which is journaled in wall 99, and a medial portion which is jou naled in the aperture of cap 101 and an enlarged head 111 which projects upwardly from the rotor and' is arranged in bearing association with the top of cap 101. flexible sealing members 115, 11 7, 119 and 121 which are arranged in vertically spaced horizontal planes' with the upper sealing member 121 disposed against cap 101 for dividing space 113 into a plurality of vertically spaced chambers 123, 125, 127 and 129.

The circumferences of the sealing members snugly engage the inner surface of rotor wall 107 while the inner surfaces of said sealing member snugly engage the outer surface of stator 105.

Thereby each of chambers 123, 125, 127 and 129 is sealed from the others thereof and is defined by an inner wall comprising a section of stator 105 and an outer wall comprising a section of rotor 97.

A pair of apertures in the chamber walls comprise inlet and outlet means for said chambers and accordingly distributor-collector 89. ■ In the present embodiment each of the receptacles 23 and 24 is associated with a pair of said last mentioned chambers in a manner such that one of each pair is an influent chamber and the other thereof is an effluent chamber. In the present and; preferred embodiment of the invention the lowermost chambers 123 and 125 are influent chambers of which chamber 123 is associated with receptacle 24, whereas chamber 125 is associated with receptacle 23. To that end, the upstream end portion 129 of duct 43 from receptacle 24 projects through one outlet opening in wall 107 in a fluid tight seal for fluid communication with chamber 123. On the other hand, the upstream end portion 131 of duct 43 from container 23 extends through the other outlet opening in wall 107 in a fluid tight seal for fluid communication with chamber 125. In the present and preferred embodiment, chambers 127 and 129 are effluent chambers which are disposed above influent chambers 123 and 125 and are in For that purpose the upper end portion 133 of duct 45 associated with receptacle 24 projects through one . inlet opening in wall 107 in a fluid tight seal for fluid communication with chamber 127. The upper end portion 135 of duct 45 associated with receptacle 23 projects through the other inlet opening in wall 107 in a fluid tight seal for fluid communication with chamber 129.

By placing influent chambers 123 and 125 below the effluent chambers, the likelihood of contamination of influent by effluent because of faulty seals in distributor- collector 89 is m inimized.

Moreover, the pressures generated within the system are such that downstream of containers 37 and 38 the effluent paths may be combined, if desired, with impunity.

Stator 105 has a plurality of vertical bores 137, 139, 141 and 143 (Figs . 4, 5 and 6) which open through the top of stator head 111.

The lower ends of bores 137, 139, 141 and 143, respectively, communicate with chambers 123, 125, 127 and 129. By reason of the foregoing, bores 137 and 139 are influent bores whereas bores 141 and 143 are effluent bores .

Charging means for moving influent or wash fluid into containers 37 and 38 and through the batches therein contained comprises a pump 153 (Fig. 2) which is arranged in fluid communication with influent bores 137 and 139 through a pair of flexible conduits 145 and 147. Said conduits together with distributor-collector 89 and ducts 43, 43 compris \e means defining an independent path or influent pathway for each of containers 37 and 38 and extending between said containers and the pump. Pump 153 may be of the roller type for impelling substantially equal volumes of influent accordingly containers 37 and 38. In the present embodiment, movement of influent through each system is simultaneous; however other than simultaneous influent movement may be desirable under washing conditions other than that specifically described herein.

Fluid from a res:ervoir 233 supplies influent for pump 153 by gravity. The reservoir is also in direct fluid communication with conduits 145 and 147 through a pair of tubes 235 and 237, which bypass the pump for gravity feed into containers 37 and 38, respectively, for a reason to become. apparent from ensuing description.

Discharging means for collecting effluent or spent wash fluid comprises an effluent tank 155, which is in fluid communication with bores 141 and 143 through duct means herein comprised of ducts 149 and 151 , respectively.

A bearing mechanism generally designated 157 (Fig. 1 and 11) for the relatively stationary part of a rotational assembly comprises a retainer 159 having a pair of spaced apart fingers 161 and 162 which define an elongated recess 163 in which an upper reduced portion 165 of stator head 111 is intimately engaged for sliding normally of an expansion band or bar 167 when the latter is in assembled condition. The retainer is captured in a pocket 166 form ed in medial section 168 of expansion bar 167 to permit sliding of the retainer longitudinally of said bar in oppos ite directions in response to corresponding stresses during rotation of rotor 97.

Bar 167 comprises a pair of opposed end sections 158 and 160 at least one of which is telescopically connected to medial section 168. Said end sections carry a pair of opposed fittings or adaptors 169 and 177 having outwardly extending hooks 171 and lower end of a skirt 1 73 (Fig. 1) hung in the top opening of the centrifuge from shell 17. An annular cushion or pad 175 is shown disposed between the said shell and skirt 173 for cushioning evident forces brought to bear. In consequence of the foregoing construction, distributor- collector 89 will be held erect during rotation of rotor 21 , fingers 161 and 162 being proportioned to prevent removal thereof. However, bar 167 may be contracted to disengage hooks 171 and 181 from skirt 173 for removing said distributor- collector from the centrifuge. Thereafter, release of the rotor 97 from bar 167 by removing the stator head from recess 163 can be achieved.

In the illustrated embodiment section 158 comprises a vertical plate 185 with which hook 1 71 is integral and a vertical plate 189. The inner end portions of said plates are arranged in sliding association with the outside of opposed parallel faces of medial section 168. The outer end portions of said plates are separated by a spacer 187 the width of which is equal to the width of section 168 from the proximate end of which said spacer is spaced. To one face of said spacer, plate 185 is secured by fasteners such as rivets 179 and to the opposite face of said spacer, plate 189 is secured by fasteners such as rivets 191. One end portion of medial section 168 has a well 1 93 in which one end of a compression spring 195 is mounted for extending block 187 and accordingly fitting 169 longitudinally of bar 167 and for holding said bar in mounted position in the centrifuge.

In addition to the condition shown in Fig. 11 , bar 167 can assume two other positions according to the condition of latch means 'K 199 of section 168. Said latch means comprises a part in the form of a rod 201 which extends through a transverse opening or slot 223 in section 168 and a pair of transversely aligned apertures 203 and 205 in telescopic section 158. . While the dimension of opening 223 longitudinally of section 168 is considerably larger than the diameter of rod 201 , the diameter of apertures 203 and 205 is such that latch means 197 is snugly engaged to lim it its movement in section 158 to transverse sliding. The diam eter of aperture 205, however, is larger than aperture 203 to accommodate sliding of another part of said latch m eans, said other part being an annular bearing extension 206 of a bearing cap 207. The latter is secured by a screw 209 on one end portion 211 of rod 201 which projects normally from the outer face of plate 189. A spring retainer 213 in the form of a cup is secured by a screw 215 to the opposite end portion 217 of rod 201 said opposite end portion projecting normally from plate 185. A compression spring 219, which is disposed about end portion 217^ has one end disposed in retainer 213 and the other end bearing against vertical plate 185 for drawing cap 207 into engagement with the outer surface of plate 189. The parts are proportioned so that under normal biasing bearing extension 206 will be drawn inwardly of plate 189 into a reduced part of opening 223.

That is to say, opening 223 has a pair of parallel limiting walls 225 and 227 spaced apart longitudinally of section 168. These walls define the limits of movement of rod 201 longitudinally of bar 167. Within the recess 223 there is generated adjacent plate 189 annular shoulder 229 within the annulus of which bearing extension the shoulder 229 is less than the space between walls 225 and 227 so that while the parts are conditioned as in Fig. 11 contraction of bar 167 will be limited by engagement of the extension 206 and the shoulder 229. The parts are proportioned so that this extent of contraction is not enough to .permit removal of ,bar 167 from the centrifuge. However, it is adequate for accommodating variation in the distance across (herein shown as a. diametric cord) skirt 1.73 and provided for bar 167 in assembled condition.

Yet another condition of the bar 167 is required for removing it from the centrifuge. This is achieved by pushing rod 201 upwardly with respect to Fig. 11 against the bias of spring 219 until cup 213 engages plate 205. The parts are proportioned so that upon the last occurrence, extension 206 will be removed from recess 223. Accordingly, rod 201 will be free for engaging wall 225. In such last condition bar 167 will have been contracted sufficiently to permit its removal from the centrifuge.

The foregoing combination enables economical employment of a disposable collector-distributor 89 for each washing operation whereby likelihpod of introduction of contaminants may be minimized.

Flow through the system defined by passaged means comprising ducts 43, 45, 149 and 151 and conduits 145 and 147 is controlled through electrical circuitry (Fig. 12) comprising three solenoids 239, 241 and 243. The latter together with said circuit are arranged within a control box 245 (Figs. 7 and 8) having an upper horizontal plate 247 relative to which a cover plate 249 is hingedly arranged for securance by a latching assembly 255. In the present embodiment, the latching assembly comprises a post aperture in the cover plate 249 so that adjoining flat surfaces of said plates may be releasably held in engaged association by a lock 259 associated with said post.

Plate 247 has a plurality of upwardly opening channels or grooves 261 , 263 and 265. Pressure feet or pads 267, 269 and 271 carried on the ends of reciprocating arms controlled by solenoids 239, 241 and 243 respectively, are arranged for extension through apertures provided therefor in the bottoms of said channels, respectively. Medial portions of tubes 235 and 237 are disposed in channel 261. Downstream portions of ducts 149 and 151 are disposed in channel 263. Portions of conduits 145 and 147, which are upstream of their communication with tubes 235 and 237, are disposed in channel 265. The parts are arranged and proportioned so that when the solenoid is de-energized the flow paths through their associated tubes, ducts and conduits are open. However, while plate 249 is closed (its normal operating condition) and a solenoid is energized, its pressure foot will be projected to clamp therewith associated ducts, conduits and tubes to cut their flow paths.

For operating the device a plug 273 (Fig. 12) for connecting the power circuit 275 of the assembly to a 115 volt A. C. power source (not shown) is provided. The primary of a transformer 277 is arranged in series in power circuit 275 which becomes energized upon closure of a push-to-make, push-to-break, double pole switch 279. In the present enbodiment of the invention, the secondary of transform er 277 is a 24 volt coil with which a selenium rectifier 281 is arranged in parallel for developing a D. C . effect. Simultaneously carried from a switch box 307, will light by reason of connection to one terminal 287 of rectifier 281 through a conductor 309 and thereby indicate the condition of the power circuit 275. The other side of said rectifier is connected to a plane of reference potential, herein shown as ground 282.

One terminal of each of solenoids 239, 241 and 243 is connected through a conductor 283 to ground. The other terminal 285 of solenoid 239 is connected to terminal 287 of said rectifier through a switch 289 of a normally closed relay 291. The other terminal 293 of solenoid 241 is connected to terminal 287 of said rectifier through a switch 295 of a normally closed relay 297. The other terminal 299 of solenoid 243 is connected to terminal 287 of said rectifier through a switch 301 of a normally closed relay 303. By reason of the foregoing construction, once the plug 273 has been connected to a power source and the switch 279 closed, solenoids 239, 241 and 243 will becom e energized whereupon pressure feet or pads 267, 269 and 271 will be conditioned for cutting flow in the system .

A grounded coil 309 (upper left of Fig. 12) of a normally closed relay 31 1 is energized upon closure of switch 279 by reason of a conductor 313 . which connects one side of said last mentioned coil and terminal 285 whereupon switch 315 of relay 311 will open. Relay 311 is arranged for lighting a . lamp 317 by reason of a circuit wire 319 which will connect said last lamp to the selenium rectifier through a conductor 318 when switch 315 is in closed condition.

To commence operation of the centrifuge, a normally depressed momentarily to closed condition. Switch 321 is connected in parallel with the starting switch of the circuit of a centrifuge motor or prime mover means for driving spindle 27 in a manner such that once closed, said circuit will continue to operate the centrifuge regardless of the condition of switch 321 until stopped by means to be hereinafter described. Said motor may be of conventional construction and accordingly it together with its circuit have been omitted in the drawings.

Relay 291 is included in multiple assembly 323 which also comprises a normally open relay 325 and a common coil 327. The. latter m ember- is connected to the circuit (not shown) of the centrifuge motor. Thereby, upon closure of switch 321 , switch 329 of relay 325 and switch 289, which are both magnetically coupled to the coil 327, respectively, will close and open. When the switch 289 opens, current flow to solenoid 239 as well as to coil 309 becomes interrupted. Thereupon pressure foot 267 will retract to open tubes 235 and 237 for establishing fluid communication between reservoir 233 and containers 37 and 38, provided rotor 21 is spinning fast enough for clamp assembly 51 to have opened. In consequence thereof the system will fill with influent and initial flow through the system will be by gravity. Also, switch 315 will assume its normally closed condition causing lamp 317 to light, thereby indicating the open condition of tubes 235 and 237 in control box 245. Simultaneously, because one terminal 331 of . relay 325 is connected to terminal 287 while the other terminal 333 of said last relay is connected to a grounded lamp 335 mounted in housing 324 through a circuit conductor 337, lamp 335 will light as The precaution of preventing initial filling of the system until a predetermined centrifugal force . is reached tends to prevent backflow from containers 37 and 38 and possible contamination of influent. Moreover, accidental emptying of container contents is also prevented by thus keeping the system closed.

Stopping of gravity flow of influent is effected by a normally open push-to-make, push-to-break, ■ double pole switch 339 which is mounted in a housing 341. Switch 339 may be operated manually as shown herein or in response to an electrical effect generated in a known manner in response to a condition such as a lapse of time or color or density of effluent accumulating in ducts 149 and 151. Once closed, switch 339 will be held in closed condition by reason of magnetic coupling to a coil 345 which is mounted in housing 341. Said coil is immediately energized on closing of switch 279. through a relay 347 whose switch 349 is normally biased to closed condition and which is connected to term inal 287 through a circuit wire 351 . A voltage reducing resistance 343 is interposed in a conductor 353 which connects coil 345 to relay 347.

A circuit wire 355 connects one term inal 357 of switch 339 to a grounded lamp 360, which when lit indicates operation of pump 153 and pump generated flow through the system . Said terminal 357 is arranged for connection, through said last switch when closed to rectifier terminal 287 through a circuit conductor 359. The other terminal 361 of switch 339 is connected to one side of a grounded relay coil 363. Coil 363 is disposed in a housing 367 for magnetic coupling to an assembly of relays comprising heretofore described rela s 297 and 303 and additional relays 369 and 371 , an open condition. . The arrangement is such that when coil 363 is energized switches 373 and 375 will be magnetically moved to closed condition whereas switches 295 and 301 will be opened.

Upon opening of switches 295 and 301 circuits for solenoids 241 and 243 are opened and said last solenoids accordingly become de-energized. Thereupon pressure feet 269 and 271 move to non-clamping condition and fluid, communication becom es established between pump 231 and containers 37 and 38 and between said containers and effluent tank 155. Simultaneously, solenoid 239 becom es energized by reason of closure of relay 369. Accordingly pressure foot 267 moves to closed, condition to interrupt flow in tubes 235 and 237. The last result is effected because one terminal 377 of relay 369 is connected to term inal 287 of rectifier 281 through a circuit wire 379 and the other terminal 380 of said relay 369 is connected to the plane of reference potential through a circuit assembly including conductor 381 . The latter connects relay 369 to a term inal 383 of a relay 385. In turn terminal 383 is connected by a circuit wire 387 to a terminal 389 of relay 289. However, relay 289 is bypassed by a circuit wire 391 which connects terminal 389 to terminal 285 of solenoid 239 for connection of the latter through bypass 391 to relay 369. In consequence of the foregoing, when relay 369 is closed the coil 309 of relay 315 will also becom e energized to magnetically impel switch 315 to an open condition thereby to extinguish lamp 317 simultaneously with the closure of tubes 235 and 237. When solenoids 241 and 243 are energized, pump 153 is also actuated by reason of closure of relay 371 which is serially connected between a pair of 115 volt A. C. circuit wires For operation, the pressure of pump 153 is set at a level sufficient to overcom e the centrifugal force created and to effect a flow through containers 37 and 38 for washing material 36 and delivering effluent to tank 155 corresponding to the influent volume. The rate of flow can be controlled in accordance with requirements and factors including the character of the material being washed. None of these factors is critical to the present invention and accordingly details of the process depending upon the character or type of material are om itted.

Suffice it to say that washing may be stopped at any desired time by closing a double pole, push-to-make, push-to-break switch 397 which is mounted in a housing 399. Said last switch may be manually operated (as illustrated) or automatically in response to an effect generated by well-known means according to lapse of time or a physical characterisitc of the effluent. Once closed, switch 397 may be held in closed condition by the magnetic force induced about a grounded coil 401 which from a terminal 403 is connected to heretofore defined circuit wire 359 through a voltage lowering resistance 405. However, switch 397 can also be released by breaking the circuit to coil 401 by depressing a normally closed interruptive switch 407 disposed in the circuit of said last coil.

Upon initial closure of switch 397 both of its term inals 409 and 411 become operatively connected to rectifier terminal 287 through circuit wire 359. In turn terminal 409 is connected to a grounded lamp 413 which accordingly will light when switch 397 is closed to indicate the closed condition of such last switch. The other pole 411 energizes grounded coil 415 of relay assembly 417. 385 and an additional and normally closed relay 41 9. Accordingly, when coil 415 is energized by reason of closure of switch 397, switch 386 of relay 385 will be magnetically moved to closed condition while the switches 349 and 420 of relays 347 and 419 will be magnetically moved to open condition. Relay 419 is connected in series with the circuit of the centrifuge motor (not shown) and accordingly when it opens the centrifuge will stop. Relay 347, because of its interposition between terminal 287 and coil 345, will interrupt the circuit to said last coil when open. Accordingly, magnetically held switch 339 will be released and current flow to lamp 360 will terminate. In consequence lamp 360 will extinguish, relays 369 and 371 will open and relays 297 and 303 will be restored to a closed position. As a result, pump action will stop (because relay 371 is open) ; solenoid 239 will be de-energized (because relay 369 is open) and solenoids 241 and 243 will become de- energized (by reason of the opening of the respective of relays 297 and 303) .

By reason of the foregoing construction controlled washing volumes can be. forced into each of containers 37 and 38 notwithstanding different resistances to flow in said containers. In prior devices while the total wash volume can.be controlled, the volume to each container is uncontrollable because differential resistance in the containers causes the paths of wash fluid which comes from a common pressure head to move in an uncontrolled fashion. In consequence of the invention, simultaneous washing of a plurality of batches of particles can be achieved in a period substantially no longer than the time required for washing a single batch. Thereby for the first time there is provided a washing centrifuge assembly of materials .

The process described has been practiced effectively in reconstituting thawed red blood cells which theretofore had been preserved by freezing and protected from freeze damage by various cryoprotective agents . Among the latter which have been removed are glycerin, an intracellular agent used in high and low concentrations, and polyvinyl pyrrolidone, an extracellular agent.

For removal of glycerinating agent from highly glycerinated frozen red blood cells, a pair of batches, each of which comprises the yield of 500 m illiliters of whole blood, is first thawed and thereafter spun in a high speed centrifuge for a period sufficient for separating the cells and available liquid. The supernatant is then removed and the red blood cells of each batch are transferred to one of containers 37 and 38, respectively, for processing in accordance with the invention.

A first wash solution, preferably an aqueous manitol- saline, for osmotically shrinking the red blood cells and thereby increasing their density, is first forced through each batch by independent pressure means for a period sufficient to condition the cells for ready separation from environmental fluid when centrifuged. Thereafter, a second wash solution having a decreasing concentration or gradient of cell shrinking agent is used to gradually decrease the level of cellular shrinkage to a nullity as a density differential between cells and environmental fluid can be maintained under centrifugal force without said agent. After the manitol has been completely dissipated the cells will restore to normal size and washing may be completed with h ertonic wash solution of about 5 lucose in normal saline. cells for use in transfusion.

The hypertonic solution may omit the 5% glucose in which event the decreasing manitol gradient may be established with isotonic saline. Moreover, if desired, the original wash solution may be omitted and all washing may be done with normal saline or the hypertonic solution. In such event, however, great care should be exercised to avoid high red cell loss during initial periods of washing. Such likelihood is minimized by manitol in the first wash solution which causes an osmotic squeeze on the red cells . Thereby, cell density is increased enabling improved separation of red cells from the less dense glycerinating agent for removal with effluent.

As many substitutions or changes could be made in the above described construction and process, and as many apparently widely different embodiments of the invention within the scope of the claims could be constructed without departing from the scope and spirit thereof, it is intended that all matter contained in the accompanying specification shall be interpreted as being illustrative and not in a limiting. sense.

Claims (27)

1. 31768/2 τ- 1. A washing centrifuge assembly comprising a centrifuge rotor, a pair of containers supported from said centrifuge rotor for rotation therewith, charging means including a pump for effecting influent flow of predetermined volume into- each of said containers under an independent pressure head as said rotor spins for washing material contained in the containers, means defining an independent influent path for each of said containers, and discharging means for collecting effluent from each of said containers in a volume corresponding to the volume of influent moved into said containers.
2. 2. An assembly according to claim 1, in which the means defining an independent influent path includes a distributor collector including a part arranged for co-rotation with said rotor and having influent outlet means, said distributor means having influent inlet means and means for isolating between said inlet means and said outlet means all influent for one container from all influent for the other.
3. 3. An assembly according to claim 2, in which said isolating means comprise a plurality of chambers arranged in said distributor collector for isolating all influent for each container from all the influent for the other container and for isolating all effluent from all influent.
4. 4. An assembly according to claim 3, in which the chambers for isolating the influent are of lowermost r-c l ec r for minimizin 31768/2 τ· contamination of influent with effluent.
5. 5. An assembly according to any one of claims 2, 3 and 4 in which said distributor collector is removably mounted on a body secured to said rotor for conjoint rotation therewith.
6. 6. An assembly according to claim 5, in which said distributor-collector comprises a stator and a rotor mounted for rotation about said stator, the rotor of the distributor-collector being keyed to said body.
7. 7. An assembly according to claim 6, in which said collector-distributor is vertically disposed with said stator haying an extension projecting upwardly from the rotor of the distributor-collector, and in which a bearing is mounted for conjoint rotation with the rotor supporting said containers, means being provided for holding said stator fixed relative to the rotor of the distributor whilst the rotor of the distributor-collector and the rotor supporting the containers are rotating.
8. 8. An assembly according to any one of claims 1 to 7, comprising an influent reservoir disposed above said containers for delivering influent to said charging means, an influent conduit arranged in fluid communication with said charging means and defining a first influent path to each of said containers, and a tube arranged in fluid communication with said reservoir and defining a second influent path bypassing said charging means for gravity feed to each of said containers through an associated one of said 31768/2
9. 9. An assembly according to claim 8 comprising an electrically energized flow control mechanism associated with said paths for establishing fluid communication between said containers and either said charging means or said reservoir.
10. 10. The assembly according to claim 9, wherein the flow control mechanism includes means for simultaneously clamping said conduits upstream of their connection to said tubes and opening said tubes, and simultaneously clamping said tubes and opening said conduits.
11. Hi The assembly according to claim 9 or 10, including effluent duct means arranged in fluid communica-tion with said discharging means for removal of effluent from said containers, said flow control mechansim arranged for stopping and permitting fLow in said effluent duct means simultaneously with the interruption and permitting of flow in said influent conduits upstream of the connection thereof to said tubes.
12. 12. The assembly according to claim 11, wherein flow control mechansim comprises a plurality of pressure members spaced from said containers for simultaneously closing said conduits and duct means for gravity filling said containers, conduits and duct means between said pressure members.
13. 13, The assembly according to any one of the preceding claims, including means responsive to centrifugal force having a first position in which flow of influent and a second position in which flow of influent and effluent into and out of said container means is open.
14. 14. The assembly according to claim 13, wherein the means responsive to centrifugal force comprises a clamping member normally biased for effecting said first clamping position and for moving to effect said second release position upon generation in said assembly of centrifugal force of predetermined magnitude.
15. 15. The assembly according to claim 14, wherein said clamping member is conjointly rotational with said rotor and including spring means for biasing said clamping member for effecting said first clamping position the resiliency of said spring means being such as to yield upon generation in said assembly of a centrifugal force of said predetermined magnitude.
16. 16. The assembly according toclaim 15, wherein said clamp member is conjointly rotational with and arranged for radial movement from a body between the clamping and the release positions, said body having an outer surface with a plurality of slots, there being two clamping members each radially arranged on said body and having a plurality of extensions, biased toward said outer surface into the clamping position.
17. 17. The assembly according to claim 16, wherein said body has a plurality of wells said slots forming an opening through said surface, each clamping member comprising a block arranged for radial movement in one of said radial arm arranged for radial movement through an associated slot, said extensions being carried on i said radial arms.
18. 18. The assembly according to claim 17, wherein the spring means for biasing said clamping members comprises a spring associated with each block for biasing a corresponding extension towards said outer surface.
19. 19. The assembly according to any one of claims 16 to 18, including elevation integral with said body aligned with said extension for impinging each clamping member.
20. 20. A process for material separation by cen-trifugation in which a first material is removed from a second material by a wash fluid which is first passed through the second material and therefrom removed with first material as spend fluid, and in which the wash fluid is passed under an independent pressure head in predetermined volumes into each of a plurality of batches of said second material while being spun about a common axis .
21. 21. The process according to claim 20, wherein the wash fluid is forced in substantially equal volumes through said batches.
22. 22. The process according to either of claims 20 or 21, wherein the wash fluid is forced through said batches substantially simultaneously.
23. 23. The process for separating red blood cells from red blood cells in preservative by centrifugation in containing a cell shrinking agent downstream through a plurality of batches of the red blood cells in preservative, simultaneously and under independent pressure heads to remove preservative from said red blood cells while the batches are spinning about a common axis and osmotically shrinking said red blood cells and increasing cell density relative to environmental fluid, and from said batches continuously removing spent wash fluid under force of said pressure heads.
24. 24. The process according to claim 2 » including the further step of decreasing the concentration of the cell shrinking agent in the wash fluid as the wash progresses.
25. 25. The process according to either of claims 23 or 24, including the step of blocking flow of wash fluid to each of said batches until generation therein of force sufficient to prevent upstream flow from said batches.
26. 26. A process for separation of red blood cells from preserved red blood cells by centrifugation in which the red blood cells contain a cryoprotective agent comprising the steps of washing while under high speed centrifugation each of a plurality of batches of preserved red blood cells with equal volumes of an aqueous manitol-containing solution under independent pressure heads for a .time and of an amount to reduce the concentration of cryoprotective agent in the environmental fluid, said manitol being present in the wash solution in an amount to shrink the said red blood cells and increase the cell density relative to the environmental fluid, and while spinning the batches about atseo/s a common axis continuously removing the spent wash fluid at a rate equivalent to the influent rate of wash fluid, decreasing the concentration of manitol in subsequent wash solutions each fed under said independent pressure heads to each batch, and as a final wash solution, an aqueous hypertonic solution containing glucose to provide reconstituted red blood cells suitable for transfusion.
27. 27. A washing centrifuge assembly substantially as hereinbefore described with particular reference to the drawings. S. HOROWITZ & CO. AGENTS FOR APPLICANTS