Serum separator system for centrifuge with piercable membrane

• US 4,957,637 A
• Filed: 05/23/1988
• Issued: 09/18/1990
• Est. Priority Date: 05/23/1988
• Status: Expired due to Term

• Current Assignee: Sherwood Services AG
• Original Assignee: Sherwood Medical Company (Medtronic Plc)
• Inventors: Cornell, William D.
• Primary Examiner(s): Jones, W. Gary
• Assistant Examiner(s): Nessler, Cynthia L.
• Application Number:
  US07/197,753
• Time in Patent Office: 848 Days
• Field of Search: 210/359, 210/514, 210/516, 210/518, 210/472, 210/782, 422/101, 604/89, 604/90, 604/184, 604/190, 604/191, 604/237, 604/406, 604/411, 494/37
• US Class Current: 210/782
• CPC Class Codes: A61B 5/15003 for venous or arterial blood
• CPC Class Codes: A61B 5/150221 Valves
• CPC Class Codes: A61B 5/150236 Pistons, i.e. cylindrical bodies that sit inside the syringe barrel, typically with an air tight seal, and slide in the barrel to create a vacuum or to expel blood
• CPC Class Codes: A61B 5/150244 Rods for actuating or driving the piston, i.e. the cylindrical body that sits inside the syringe barrel, typically with an air tight seal, and slides in the barrel to create a vacuum or to expel blood
• CPC Class Codes: A61B 5/150251 Collection chamber divided into at least two compartments, e.g. for division of samples injection syringes having more than one chamber A61M5/19; syringes for injection of two or more media A61M5/2448, A61M5/284; sample preparation for further analysis A61B5/150755
• CPC Class Codes: A61B 5/150259 Improved gripping, e.g. with high friction pattern or projections on the housing surface or an ergonometric shape
• CPC Class Codes: A61B 5/150267 Modular design or construction, i.e. subunits are assembled separately before being joined together or the device comprises interchangeable or detachable modules
• CPC Class Codes: A61B 5/150351 Caps, stoppers or lids for sealing or closing a blood collection vessel or container, e.g. a test-tube or syringe barrel caps for bottles or containers in general B65D41/00
• CPC Class Codes: A61B 5/150389 Hollow piercing elements, e.g. canulas, needles, for piercing the skin
• CPC Class Codes: A61B 5/150496 Details of construction of hub, i.e. element used to attach the double-ended needle to a piercing device or sampling device
• CPC Class Codes: A61B 5/150755 Blood sample preparation for further analysis, e.g. by separating blood components or by mixing
• CPC Class Codes: A61B 5/153 Devices specially adapted for taking samples of venous or arterial blood, e.g. with syringes
• CPC Class Codes: A61M 1/029 Separating blood components present in distinct layers in a container, not otherwise provided for containers for storing blood or blood components A61J1/05; sampling or analysing blood by separating blood components G01N33/491
• CPC Class Codes: B01L 3/5021 Test tubes specially adapted for centrifugation purposes centrifuges B04B5/04
• CPC Class Codes: G01N 33/491 by separating the blood components G01N15/05 takes precedence

Abstract

A device for separating and isolating heavier components from lighter components of blood mixtures after centrifugal separation, comprising a barrel for holding the blood mixture having slidably positioned therein an inner container for containing the lighter components, a one-way valve responsive to movement of the container within the barrel (a) for controlling the flow of the lighter components into the container, (b) for preventing the lighter components from re-entering the barrel from the container, and (c) for creating a vacuum to assist in drawing the blood mixture to be separated into the barrel, and a filter for filtering the lighter components during their entry into the inner container. The inner container includes an opening for access to the separated and isolated lighter components.

Claims

1. An assembly to be used in connection with a centrifuge, for separating and isolating lighter components from heavier components of blood mixtures, comprising:

an elongated barrel for holding a blood specimen, said barrel being open at its upper end and including a piercable membrane across its lower end, said membrane being adapted to be selectively pierced by a needle such that a blood specimen drawn through said needle may enter into said barrel;

a mating container positioned in said barrel and slidable therein as a plunger, said container including a fluid opening at both its lower end and its upper end;

means for selectively sealing said lower opening of said container depending on the direction of container movement in said barrel, said sealing means becoming closed when said container is pulled upwardly in the barrel such that a vacuum is created in said barrel solely by relative movement of said barrel and said container, said sealing means becoming open when said container is pushed downwardly in the barrel allowing liquid to pass from said barrel, through said lower opening and into said container; and

filtration means located at the lower end of said container for permitting the passage of soluble components of said blood specimen from said barrel to said container, but preventing passage of insoluble components when the container is pushed into the barrel with said upper opening of said container open.

2. The assembly according to claim 1 wherein said upper opening of said container is sealable by a removable airtight cap.

3. The assembly according to claim 1 wherein said barrel and said mating container are circular in cross section.

4. The assembly according to claim 1 wherein the barrel has a means defining a passageway having a first end in fluid communication with the inside of said barrel and a second end in fluid communication with the outside of said assembly when said sealing means passes said first end during extreme upward movement of said container, said first end of said passageway being located along said barrel such that said vacuum created during upward movement is equilibrated with the pressure outside said assembly just before said container is separated from said barrel, thus avoiding air turbulence within said barrel.

5. The assembly according to claim 1 wherein said sealing means comprises a one-way valve for allowing liquid from said barrel to pass through said lower opening of said container when the container is pushed into said barrel and for preventing flow of liquid from said container to said barrel when the container is pulled from said barrel or said barrel is stationary.

6. The assembly according to claim 5 wherein said one way valve further comprises a plate of flexible material which is rigidly supported on one side and positioned within said barrel such that said plate bends towards the unsupported side when the container is pushed into the barrel, thereby allowing liquid from said barrel to pass through said lower opening of said container, said plate remains against the rigid support when the container is pulled from the barrel forming a liquid tight seal between the container and the barrel which prevents liquid in the container from re-entering the barrel.

7. The assembly according to claim 5 wherein said one-way valve comprises:

an elastomeric sealing disc having a circumferential sealing edge and being substantially similar in shape to the cross-sectional shape of said barrel; and

a rigid support plate attached to said container adjacent to said lower opening of said container and slidable therewith in said barrel, said support plate supporting said sealing disc and being substantially similar in shape to that of said sealing disc, said support plate and said sealing disc being located within said barrel such that when said container movement is upward relative to said barrel, said sealing edge frictionally contacts the inner walls of said barrel and forces downward against said support plate, thus preventing said flow of liquid between said barrel and said container, and when said container movement is downward relative to said barrel, said sealing edge rises owing to said frictional contact, thereby allowing said liquid from said barrel to enter said lower opening of said container.

8. The assembly according to claim 1, further comprising a locking means for locking said container in an upper position within said barrel, thereby preventing unintended movement of said container within said barrel during centrifuging.

9. The assembly according to claim 8 wherein said locking means comprises:

a locking means including a recessed step located around said container; and

a flexible oval-shaped flange located at said upper opening of said barrel, a portion of said oval flange positioned in an overlapping relationship with the path of said container within said barrel so that when said recessed step of said container aligns with said oval flange, said overlapping portion secures itself against said recessed step, thereby preventing movement of said container into said barrel, said oval-shaped flange transformable to a shape which is substantially similar to the cross section of said container, thereby disengaging said flange from said recessed step and allowing container movement within said barrel.

10. The assembly according to claim 1 further comprising means for equilibrating gaseous pressure within said barrel and gaseous pressure outside of said barrel just prior to separating said container from within said barrel, thus avoiding air turbulence within said barrel when said container is separated from within said barrel.

11. The assembly according to claim 10 wherein said means for equilibrating said gaseous pressures includes means defining a passageway disposed along said barrel, said passageway means being positioned such that said gaseous pressure in said barrel will equilibrate with said pressure outside of said barrel only during extreme upward movement of said container within said barrel.

12. An assembly to be used in connection with a centrifuge, for separating and isolating lighter components from heavier components of blood mixtures, comprising:

a first elongated barrel for holding a blood specimen, said barrel being open at its upper end and including a needle at its lower end for providing entry of said blood specimen;

a container positioned in said barrel and slidable therein as a plunger, said container including a fluid opening at both its lower end and its upper end;

means for selectively sealing said lower opening of said container depending on the direction of container movement in said barrel, said sealing means becoming closed when said container is pulled upwardly in the barrel such that a vacuum is created in said barrel, said sealing means becoming open when said container is pushed downwardly in the barrel allowing liquid to pass from said barrel, through said lower opening and into said container;

filtration means located at the lower end of said container for permitting the passage of soluble components of said blood specimen from said barrel to said container, but preventing passage of insoluble components when the container is pushed into the barrel with said upper opening of said container open; and

a locking means including a recessed step located around said container and a flexible oval-shaped flange located at said upper opening of said barrel, a portion of said oval flange positioned in an overlapping relationship with the path of said container within said barrel so that when said recessed step of said container aligns with said oval flange, said overlapping portion secures itself against said recessed step, thereby preventing movement of said container into said barrel, said oval-shaped flange transformable to a shape which is substantially similar to the cross section of said container, thereby disengaging said flange from said recessed step and allowing container movement within said barrel.

13. An assembly to be used in connection with a centrifuge, for separating and isolating lighter components from heavier components of blood mixtures, comprising:

a first elongated barrel for holding a blood specimen, said barrel being open at its upper end and including a needle at its lower end for providing entry of said blood specimen, said barrel having a means defining a passageway comprising a first end in fluid communication with the inside of said barrel and a second end in fluid communication with the outside of said assembly when said sealing means passes said first end during extreme upward movement of said container, said first end of said passageway being located along said barrel such that said vacuum created during upward movement of said container in said barrel is equilibrated with the pressure outside said assembly just before said container is separated from said barrel, thus avoiding air turbulence within said barrel;

a container positioned in said barrel and slidable therein as a plunger, said container including a fluid opening at both its lower end and its upper end;

means for selectively sealing said lower opening of said container depending on the direction of container movement in said barrel, said sealing means becoming closed when said container is pulled upwardly in the barrel such that a vacuum is created in said barrel, said sealing means becoming open when said container is pushed downwardly in the barrel allowing liquid to pass from said barrel, through said lower opening and into said container; and

filtration means located at the lower end of said container for permitting the passage of soluble components of said blood specimen from said barrel to said container, but preventing passage of insoluble components when the container is pushed into the barrel with said upper opening of said container open.

14. A method for separating and isolating the lighter components of a blood specimen from its heavier components comprising the steps of:

providing a device having a barrel with an upper opening and means for selectively introducing said blood specimen, using a needle through a lower end of said barrel, said introducing means comprising a piercable membrane, a container acting as a fluid plunger slidable within said barrel between upper and lower positions, said container including a lower opening and an upper opening, one-way valve means disposed on said lower opening of said container between said container and said barrel for controlling fluid flow therebetween, said valve means operating in response to the direction of container movement within said barrel wherein upward container movement opens said valve and downward container movement closes said valve, and filter means disposed immediately above said one-way valve means within said fluid flow;

lifting said container within said barrel such that said valve means closes, thereby creating a vacuum within said barrel;

using said created vacuum within said barrel to draw in said blood specimen from a blood source;

removing said needle from said membrane;

centrifuging said barrel such that said container blood specimen separates into lighter and heavier fluid components, said lighter fluid components being located closer to said container than said heavier components;

lowering said container into said lighter fluid components such that said valve means opens and said lighter fluid components flow past said filter means into said container; and

lifting said container such that said valve means closes, thereby isolating said lighter components from said heavier components.