Magnetic tumble stirring method, devices and machines for mixing in vessels

• US 6,176,609 B1
• Filed: 10/13/1998
• Issued: 01/23/2001
• Est. Priority Date: 10/13/1998
• Status: Expired due to Term

• Current Assignee: V&P Scientific, Inc.
• Original Assignee: V & P Scientific, Inc.
• Inventors: Cleveland, Patrick H., Markle, John R.
• Primary Examiner(s): Popovics, Robert
• Application Number:
  US09/170,459
• Time in Patent Office: 833 Days
• Field of Search: 366/273, 366/274, 422/102, 435/288.4
• US Class Current: 366/273
• CPC Class Codes: B01F 33/452 using independent floating stirring elements

Abstract

The invention provides a simple method, device and several machines for simultaneously stirring thousands of vessels or wells of microplates in a robust manner and with economy. This method uses the simple principle of magnetic stirrers aligning themselves to a vertical driving magnetic field placed beneath them and moving laterally or by moving the vessels over a stationary magnetic field or by spinning the drive magnets, or by using a modulating/reversing electromagnetic field to produce the moving effect. Each vessel contains a magnetic disc, bar, dowel or other shape (stirrers) which in it'"'"'s magnetic attraction to the vertical driving magnetic field will cause it to move and align it'"'"'s magnetic field as the opposite poles of the drive magnet and the stirrer attract each other. The attraction of the stirrers to the vertical driving magnetic field causes the stirrers to stand on end and tumble as the stir devices try to align to the opposite moving magnetic pole. The stirrers tumble because the walls of the vessels or friction with the vessel bottom prevents their lateral movement.

Claims

1. A method of mixing the contents of each of a two-dimensional array of vessels, each vessel having a vertical axis as defined when the vessel is disposed for the mixing of said contents, the method comprising the steps of:

(a) placing magnetic stirrers within said vessels; and

(b) when the vessels are disposed for the mixing of said contents, rotating a permanent magnet about a non-vertical axis of rotation that is so disposed adjacent the array that said rotation of the magnet provides magnetic flux lines that rotate through 360 degrees within a non-horizontal plane within each of the vessels to thereby cause the magnetic stirrers therein to tumble in at least one direction that is other than about the vertical axis of each vessel;

whereby the contents of each vessel containing a said magnetic stirrer are mixed by the tumbling of said magnetic stirrer.

2. A method according to claim 1, wherein said at least one direction is along the vertical axis of each vessel.

3. A method according to claim 1, wherein the axis of rotation is horizontal.

4. A method according to claim 1, wherein the axis of rotation is beneath the array.

5. A method according to claim 1, wherein the array is elongated in a direction parallel to the axis of rotation and the permanent magnet is elongated in said parallel direction.

6. A method according to claim 1, wherein the array of vessels are embodied as wells in a microplate.

7. A system for mixing the contents of each of a two-dimensional array of vessels, each vessel having a vertical axis as defined when the vessel is disposed for the mixing of said contents, the system comprising:

means for receiving an array of vessels in a disposition for the mixing of said contents;

a permanent magnet disposed in relation to the receiving means for rotation about a non-vertical axis of rotation that is so disposed adjacent the array that said rotation of the magnet provides magnetic flux lines that rotate through 360 degrees within a non-horizontal plane within each of the vessels to thereby cause magnetic stirrers therein to tumble in at least one direction that is other than about the vertical axis of each vessel; and

means for so rotating the permanent magnet;

whereby the contents of each vessel containing a said magnetic stirrer are mixed by the tumbling of said magnetic stirrer.

8. A system according to claim 7, wherein said at least one direction is along the vertical axis of each vessel.

9. A system according to claim 7, wherein the axis of rotation is horizontal.

10. A system according to claim 7, wherein the axis of rotation is beneath the array.

11. A system according to claim 7, wherein the array is elongated in a direction parallel to the axis of rotation and the permanent magnet is elongated in said parallel direction.

12. A system according to claim 7, wherein the array of vessels are embodied as wells in a microplate.