V & P Scientific, Inc.

John R Markle

Patrick H Cleveland

The invention provides a simple method, devices and several machines for simultaneously stirring and aerating thousands of vessels or wells of microplates in a robust manner and with economy. This method uses the simple principle of magnetic stirrers being levitated vertically when passed laterally or vertically through a strong horizontal dipole magnetic field. The dipole magnetic fields may be produced by using permanent magnets, electromagnets or a modulating/reversing electro-magnetic field. Each vessel contains a magnetic ball, disc, bar, dowel or other shape (stirrers) which in their magnetic attraction to the dipole magnetic field will cause the stirrers to levitate up in the vessel as the stirrer's magnetic poles attempt to align with the center of the dipole's magnetic field. The stirrers will fall to the bottom of the vessel by gravity or by changing the relative position of the levitating magnetic field to pull them down, or by passing the vessel laterally over another magnetic field. The up and down movement of the stirrers provides a vigorous mixing of the contents of many vessels at same time. If the level of the vessel's meniscus is situated so the stirrers pass through it on their way up and down, the air/liquid interface is significantly increased thereby significantly increasing aeration of the liquid.

Magnetic levitation stirring devices and machines for mixing in vessels

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.

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San Diego, CA, United States of America

John R Markle