AU592598B2

AU592598B2 - Centrifuge

Info

Publication number: AU592598B2
Application number: AU63683/86A
Authority: AU
Inventors: Louis W. Feldman; David H. Yawn
Original assignee: Cardiovascular Systems Inc
Current assignee: Terumo BCT Inc
Priority date: 1985-10-11
Filing date: 1986-10-10
Publication date: 1990-01-18
Anticipated expiration: 2006-10-10
Also published as: AU6368386A; GB2181371A; NL191454B; IT8648534A0; GB2181371B; IT1199260B; JPS62117650A; NL8901341A; FR2588489B1; DE3634631C2; DE3634631A1; FR2588489A1; NL94802C; NL191454C

Description

PATENTS ACT 1952-1973 592598 Farm COMPLETE SPECIFICATION (OR I GINAL) FOR OFFICE USE class:.

Int. Cl: Application Number: Lodged: Complete Specification-Lodged: Accepted: Published, ThJ~ doca~ r-t ctain the mcoae a[3g made ua44r sectlOn 49, dnd $Oorr~kr Prtits, Priority: Related Art: TO BE COMPLETED BY APPLICANT Name of Applicant: eCpR~b1 'jP1 S~ Ts Ns, Lt'~ Address of Applicant: al-0s T'H-vv ev-IcCc*, t'1L kc O $c rn~ Actual Inventor: e clsJ Irr tc.'c Address for Service, tso zs' CrQt Complete Specification for the Invention entitled: "C.t'aT K, 1-1 C S The following statement Is a full description of this invention, including the best mexftod of performing it known to me:-' 'Note: The description Is to be typed In double spacing, pica typo face, In an area not exceeding 250 mm In depth and 160 mm In width, on tough white paper of good quality and It is to be Inserted Inside this forrm.

11583175.-L 12587S-Lr 0. Atkinsen, Goernmment Printer, Canberra O i 6

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CENTRIFUGE

This invention relates to a centrifuge and to a bowl for use therewith.

When centrifuges are in use, forces are created which urge the bowl upwardly. If the apparatus holding the bowl fails, comes loose, or is improperly connected these upward forces can cause the bowl to disengage resulting in damage to equipment and possibly personnel.

10 The present invention, as least in its preferred embodiments, attempts to mitigate at least some of these problems.

According to the present invention there is provided a centrifuge comprising a bowl having a bottom and a side wall, with at least one recess in said side wall for receiving a pin whereby said bowl can be retained on a rotatable table.

Advantageously, the centrifuge includes a rotatable table having at least one pin to engage in said recess and a spring arranged to bias said bowl away from said rotatable table.

Preferably, said recess is configured so that said bowl can be mounted on said rotatable table by aligning part of said recess with said pin, pressing 25 said bowl towards said rotating table against the bias of said spring, rotating said bowl relative to said rotatable table, and releasing said bowl.

Advantageously, the bowl has a side wall which does not taper outwardly from top to bottom.

Preferably, the centrifuge comprises a shell mounted within the bowl.

Advantageously, the centrifuge further comprises a core, the bowl has a neck, and seal means are provided between the core and the neck.

Preferably, said seal means are connected to said core and sealingly contact said neck.

ir I i i \1- 2 Advantageously, said seal means are disposed circumjacent the outer periphery of said neck.

Preferably, a portion of said core extends into said neck, said portion having a diameter smaller than the diameter of said neck so that an annular channel is formed between said portion of said core and said neck, said seal means being disposed to inhibit liquid which flows through said annular channel, in use, exiting said centrifuge.

Preferably, said centrifuge includes non-return means which, when said centrifuge is in use, permit liquid to flow to the vicinity of said seal and which, when said centrifuge is stationary inhibit the return of liquid to said bowl.

Advantageously, said neck comprise a tube of non-corrodable material.

°a b, The non-return means may conveniently comprise F A a tube of flexible material mounted on said neck. In the f*O preferred embodiments, the tube of flexible material contacts a stationary nut which is part of the core, thereby forming a seal which inhibits blood and other matter from flowing to the seal means. However, as the bowl spins, the tube of flexible material is deformed, permitting outwardly forced particles such as 25 particulate contaminants to flow into a trap zone 41, between the tube -of flexible material and the seal means. When the tube of flexible material has deformed so that it no longer contacts the nut, no abrasion of the seal due to contact with the nut is possible.

a, 30 In preferred embodiments of the invention the bowl is designed so that the forces developed therein 4. 4§ a *have a downward component which helps hold the bowl down while it is spinning.

The present invention also provides a bowl for use in a centrifuge in accordance with the invention, r,.

i i r said bowl iJ whereby sa: j I ~I I 1 having at least one recess for receiving a pin id bowl can be retained on a rotatable table.

Preferably, said bowl is generally cylindrical

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jr f and comprises side wall means, top wall means connected to the top of said side wall means, said top wall means forming the top of said bowl means, bottom wall means connected to the bottom of said side wall means, said bottom wall means forming the bottom of said bowl means, and said side wall means not tapering outwardly from top to bottom of the bowl.

:o .t, 4 U U 6I 4 'Sil *t 4 i 4 For a better understanding of the invention reference will now be made, by way of example, to the accompanying drawings, in which:- FIG. 1 is a cross-sectional view, drawn to scale, showing a bowl in accordance with the invention being placed on a rotatable centrifuge table which is secured to a motor; FIG. 2 is a fragmentary side view, to an enlarged scale, showing a recess in the side of the bowl for receiving end holding a pin projecting inwardly from the rim of the centrifuge table; FIG. 3 is a view taken along line III-III of Fig. 2; FIG. 4 is a view taken along line IV-IV of 00 #9r *I 9 0 O S 9 *P 9 #9 (9 15 Fig- 2; FIG. 5 is a cross-sectional view, drawn to scale, of one embodiment of a centrifuge in accordance with th- invention; FIG. 6 is a cross-sectional view, drawn to scale, of the upper part of another embodiment of a centrifuge in accordance with the invention; and FIG. 7 illustrates the outline, in plan, of part of the nuts used in the embodiments shown in FIGS. 5 and 6.

9444i r4 *9 14 *t 4 94 9 #4 99 4 944 4 1r 9 25 Referring to FIG. 1, a bowl 1 is emplaceable on and secureable to a rotatable table 2 by means of three pins, one of which, pin 3, is shown. The bottom of the bowl 1 is provided with a protrusion 4 which is received in a recess 5 in the table 2. A plunger 6 30 contacts the protrusion 4 and, due to the upward force of a spring 7, pushes up against the protrusion 4 thereby forcing the bowl 1 upwardly. The rotatable table 2 is secured to the motor shaft 8 of a conventional motor 9. The motor 9 is conventionally mounted on a motor mount member c.

In the preferred embodiment there are three pins 3 in the rotatable table 2, but it should be understood that any suitable number, one or more, may be used. The bowl 1 has a recess for receiving each pin. As better shown in FIGS. 2, 3 and 4, the recess 11 has an inlet groove 12 and a valley groove 13 which communicates with the inlet groove 12 but is circumferentially displaced relative thrreto. Because of the upward force of the spring 7, the bowl 1 must be pushed down so that the pin 3 enters the inlet groove 12. When the bowl 1 has been moved sufficiently downward, turning either the bowl 1 or the rotatable table 2 in the correct direction will move the pin 3 to a point above the valley groove 13. When downward pressure on the bowl. is released the pin 3 will be held in the valley groove 13, To facilitate emplacement of a bowl, more recesses than pins can be provided.

Referring now to FIG. 5, there is shown a centrifuge which is generally identified by reference numeral 110. The centrifuge 110 has a stationary core 120 about which a bowl 111 is rotatably mounted. The core 120 has an inlet 122 for receiving the liquid to be **~,centrifuged. The inlet 122 communicates with a bowl tube A' 142 through which the liquid flows into the interior of the bowl 111. Centrifuged supernatant liquid, such as blood serum and wash, flow upwardly from the interior of the bowl 111 into the outlet channel 126 to the outlet 128 from which it exits the device.

El.ements, such as blood cells and platelets (which are known as "formed elements"), accumulate in space between the interior surface of the bowl 111 and the exterior surface of a shell 150 disposed within the bowl 111.

The core 120 has a stationary nut 130 which is configured to receive, guide and seal the bowl 111. The

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rn at Ii ii 6 shoulder 131 of 'the nut 130 has secured thereto a seal 132. The seal 132 sealingly contacts a tube 134 creating a dynamic seal. In the preferred embodiment the seal 132 is made of polyurethane or TEFLON (Registered Trade Mark); the tube 134 is made of metal, such as stainless steel or aluminium; and the bowl 111, the shell 150, the core 120, and baffle 144 are made of LEXAN (Registered Trade Mark).

The tube 134 is emplaced about the neck 141 of the bowl 111. The tube 134 does not extend along the entire length of the neck 141. If desired, another tube, similar to the tube 235 of FIG. 6 (hereinafter described), can be used about the neck 141 to operate as it does in the embodiment of FIG. 16.

A baffle 144 is mounted on the bowl tube 142 4 to baffle the flow of liquid into the top channel 143.

*Beads 145 serve to facilitate the mounting of the baffle 144 and provide contact points between the baffle 144 and the core 120. The beads 145 are spaced intermittently so -hat flow through the top channel 143 is possible. The bottom of the bowl 111 has a protrusion 114. The shell 150 is secured to the bowl 111 by top mount 152 and by bottom mount 153. The mounts 152 and 153 are perforated so that centrifuged fluid may flow to top channel 143 and into outlet channel 126. The shell 150 is hollow and-serves to create an area in the bowl 140 for the accumulation of formed elements.

Because of the configuration of the bowl 111 in which the side wall 154 is perpendicular to the top wall 155, and that of the shell 150 in which its side wall 157 is perpendicular to its top wall. 158 and to its bottom wall 159, the upwardly-directed component of the forces generated by spinning which would tend to impel the bowl upwardly are reduced. Also, by flattening the bowl 111 as compared to prior art bowls and by r ~i -~s;;a-ia~m*raauarr~ 1--~-*l-urrwi~~r increasing its diameter greater centrifugation (separation) forces are generated at lower speeds.

A centrifuge bowl may substantially as shown in FIG. 5 should produce hematocrits of about 55% to at 3450 r.p.m. and result in a greater amount of platelet retention, whereas commercially available prior art devices produce hematocrits of 50% to 55% at this speed. Also minimal levels of hemolysis are achieved.

Referring now to FIG. 6, there is shown the upper part of a centrifuge which is generally identified by reference numeral 210. The centrifuge 210 has a stationary core 220 about which a bowl 211 is rotatably mounted. The core 220 has an inlet 222 for receiving the liquid to be centrifuged. The inlet 222 communicates with an inlet channel 224 which in turn communicates with a bowl tube 242 through which the liquid flows into the interior of the bowl 211.

Centrifuged supernatant liquid, such as blood serum and wash, flow upwardly from the interior of the bowl 211 into the outlet channel 226 to the outlet 228 from which is exits the device.

Elements, such as blood cells and platelets (which are known as "formed elements"), accumulate in the space between the interior surface of the bowl 211 and the exterior surface of a shell 250 disposed within the bowl 211. The locating taper 221 on the core 220 facilitates emplacement of the bowl 211 on a motorized table apparatus (not shown).

The core 220 includes a stationary nut 230 30 which is configured to receive, guide and seal the bowl 211. The shoulder 231 of the nut 230 has secured thereto a seal 232. The seal 232 has an accordion member 233 for dynamically sealing against the tube 234. In the preferred embodiment the seal 232 is made of an elastomer such as polyurethane or a polymer such as i i~c( .i iY-~l- i 1I*~--LI^UUUI 0 do 00 i 04 44 O 44 .94* TEFLON (Registered Trade Mark); the tube 234 is made of metal such as stainless steel or aluminium; and the bowl 211, the shell 250, the core 220, and baffle 244 are made of LEXAN (Registered Trade Mark).

The tube 234 is emplaced about the neck 241 of the bowl 211. The tube 234 does not extend along the entire length of the neck 241. Another tube, the tube 235, is disposed about the neck 241 and extends beyond it so that its top edge or lip abuts the lower side of the top part of the stationary nut 230. The tube 235 is made of a material which will deform outwardly from neck 241 in response to rotational forces, so that in operation its top edge or lip moves outwardly with respect to the core 220 thereby permitting flow from 15 trap channel 236 to trap zone 237. Unwanted particulate contaminates and abraded particles flow toward the seal 232 due to the upward and outward components of rotational forces. As the speed of the centrifuge is reduced and then stops, the tube 235 again contacts the nut 230, thereby closing off the trap zone 237 and inhibiting the back flow of particulate contaminants.

The baffle 244 is mounted on the bowl tube 242 to baffle the flow of liquid into the top channel 243.

The shell 250 is secured to the bowl 211 by a 25 top mount 252 and by a bottom mount (not shown). The shell 250 is hollow and serves to create an area for the accumulation of formed elements. The top mount 252 and the bottom mount are perforated so that centrifuged fluid may flow to top channel 243 and into outlet 30 channel 226.

Because of the configuration of the bowl 211 and tne shell 250 in which the sides taper inwardly from top to bottom, the upwardly-directed component of the forces generated by spinning which tend to impel the bowl 211 upwardly are reduced. Also, by flattening the 4 4 44 00*4 4 4 0004 LI 4.1 04 1 i- 9 bowl 211 and by increasing its diameter greater centrifugation (separation) forces are generated at lower speeds.

A centrifuge bowl made substantially as shown in FIG. 6 consistently produces hematocrits of about to 60% at 3450 r.p.m. and results in a greater amount of platelet retention, whereas commercially available prior art devices produce hematocrits of only about 50% to at this speed. Also minimal levels of hemolysis are I 10 achieved.

'I FIG. 7 illustrates the preferred outline of the clamping surface 138 or the clamping surface 238.

The surface is provided with flat portions 39 which f t facilitate emplacement of clamping, holding or j 7 15 stabilizing devices about the top of the bowl. Since the I diameter of the nuts 130 or 230 is relatively large more gripping surface is provided for a clamping device to grip as compared to prior art devices. Also, the nuts 130 and 230 are located relatively close to the bowls 111, 211 as compared to the point of clamping on various prior art devices, thereby providing a more stable clamp.

As compared to various prior art devices the bowls disclosed are flatter, wider, and their side walls do not tiper outwardly. This permits larger areas of more uniform forces to be created within the bowl which facilitates cell retention and washing. Also the Sconfiguration and shape of such bowls permits higher i forces to be built up at lower speeds so that motors used to rotate the bowls, such as conventionally available 3450 r.p.m. motors, do not need to be boosted to higher speeds to achieve greater forces and better results.

Claims

1. A centrifuge comprising a bowl having a bottom and a side wall, with at least one recess in said side 4 wall for receiving a pin whereby said bowl can retained on a rotatable table.

2. A centrifuge as claimed in Claim 1, inc-luding a rotatable table having at least one pin to engage in said recess and a spring arranged to bias said bowl away from said rotatable table.

3. A centrifuge as claimed in Claim 2, wherein said recess is configured so that said bowl can be mounted on said rotatable table by aligning part of said rotaingtable against the bias of said spring, rotating said bowl relative to said rotatable table, and releasing said bowl.

4. A centrifuge as claimed in any preceding J Claim, wherein said bowl has a side wall which does not taper outwardly from top to bottom.

5. A centrifuge as claimed in any preceding Claim, further comprising a shell mounted within said bowl.

6. A centrifuge as claimed in any preceding Claim, further comprising a core, wherein said bowl has a neck, and seal means are provided between said core and said neck.

7.Acentrifuge as claimed in Claim 6, wherein 0 V said seal means are connected to said core and sealingly 4- contact said neck.

9. A centrifuge as claimed in Claim 5 or 6, wherein said seal means are disposed circumjacent the outer periphery of said neck. 9. A centrifuge as claimed in Claim 8, wherein a portion of said core extends into said neck, said portion having a diameter smaller than the diameter of said neck so that an annular channel is formed between 4. AIOU 0 A i said portion of said core and said neck, said seal means being disposed to inhibit liquid which flows through said annular channel, in use, exiting said centrifuge. A centrifuge as claimed in Claim 9, including non-return means which, when said centrifuge is in use, permit liquid to flow to the vicinity of said seal and which, when said centrifuge is stationary inhibit the return of liquid to said bowl.

11. A centrifuge as claimed in Claim 10, wherein said neck comprises a tube of non-corrodable material.

12. A centrifuge as claimed in Claim 10 or 11, wherein said non-return means comprises a tube of flexible material mounted on said neck. 4* 4* 4*4 4* 4*4 4* 4* 4*4*4 9* *4 4*4 4* 4 4* 4* 4* t 4* 0 4*44*4 4*44*t4 4* 4 4* 4* 4*

13. A centrifuge substantially as hereinbefore 15 described with reference to Figures 1 to 4, or Figures and 7, or Figures 6 and 7, of the accompanying drawings.

14. A bowl for use in a centrifuge as claimed in Claim 1, said bowl having at least one recess for receiving a pin whereby said bowl can be retained on a rotatable table. A bowl as claimed in Claim 14, said bowl being generally cylindrical and comprising side wall means, top wall means connected to the top of said 25 side wall means, said top wall means forming the top of said bowl means, bottom wall means connected to the bottom of said side wall means, said bottom wall means forming the bottom of said bowl means, and said side wall means not tapering outwardly from top to bottom of the bowl. I DATED this NINTH day of OCTOBER 1989 Cardiovascular Systems Inc Patent Attorneys for the Applicant SPRUSON FERGUSON 1~ I