Floating magnetic stirrer for culture medium

Claim 2

A stirrer apparatus for stirring a liquid medium in a flask comprising: (a) a flask for holding liquid medium, (b) stirrer means for stirring substantially all of the liquid medium in the flask comprising an element of magnetically attractable material, and buoyant means for supporting said element in the liquid medium in the flask, said element and said buoyant means having a density less than the density of the liquid medium, and (c) means for causing said stirrer means to rotate while supported in the liquid medium generally about an axis substantially perpendicular to the surface of the liquid medium, said axis extending through said stirrer means, whereby the stirrer means is rotated by said rotating magnetic field and effects the stirring of substantially all of the liquid medium in the flask.

Claim 3

The stirrer apparatus of claim 1, said element comprising a bar magnet.

Claim 4

The stirrer apparatus of claim 1, said buoyant means comprising an envelope housing said element.

Claim 5

The stirrer apparatus of claim 2, said buoyant means comprising a hermetically sealed envelope, said bar magnet being within said envelope.

Claim 6

The stirrer apparatus of claim 4, said envelope comprising a cylinder, said bar magnet being substantially parallel to the envelope axis.

Claim 7

The stirrer apparatus of claim 5, said cylinder having hemispherical ends.

Claim 8

The stirrer apparatus of claim 5, said envelope having a pair of bulbous elements at the ends thereof.

Claim 9

The stirrer apparatus of claim 4, said envelope comprising a pair of spherical elements.

Claim 10

The stirrer apparatus of claim 1, the stirrer means having a density approximately one-half of the density of the liquid.

Claim 11

The combination of claim 1, said flask having cylindrical walls, a bottom, and means defining a trough in the bottom part of the flask comprising a centrally located upstanding conical portion.

Claim 12

The stirrer apparatus of claim 1, said rotating field creating means comprising a magnet, and means for rotating said magnet.

Claim 13

The combination of claim 11, said flask being above said last mentioned magnet.

Claim 14

The combination of claim 11, said flask having a longitudinal axis, and means for supporting said flask with its axis inclined to the vertical.

Claim 15

The stirrer apparatus of claim 1, and said stirrer means further comprising impeller means for generating an upward flow of liquid medium in said flask.

Claim 16

The stirrer of claim 14, the stirrer means having a density less than that of said liquid.

Claim 17

The combination of claim 15, said impeller means comprising blades in said liquid beneath said buoyant means.

Claim 18

A stirrer for use in stirring a liquid medium in a vessel comprising: (a) a linearly extending body of magnetically attractable material, (b) a hermetically sealed, buoyant envelope encompassing said body being of greater volume than said body, and being of plastic material capable of withstanding wet steam at 123°, (c) said magnetically attractable body and said buoyant envelope together having a density less than the density of the liquid medium.

Claim 19

A stirrer for use in stirring a liquid medium in a vessel comprising: (a) a linearly extending body of magnetically attractable material, (b) a hermetically sealed, buoyant envelope encompassing said body being of greater volume than said body, and being of plastic material capable of withstanding wet steam at 123°, (c) said magnetically attractable body and said buoyant envelope together having a density less than the density of the liquid medium.

Claim 20

The stirrer of claim 17, said envelope having bulbous ends.

Claim 21

The stirrer of claim 17 or 18, said stirrer comprising impeller means for generating an upward flow of liquid medium in a flask in which said stirrer is placed.

Claim 22

The stirrer of claim 17, said magnetically attractable body being a bar magnet.

Claim 25

The method of claim 21, wherein the flask has an upstanding conical portion centrally located in the bottom thereof to define a trough thereabout with the side walls of the flask, said side walls being equally distant from the axis of said conical portion, and positioning said flask with the axis of said conical portion substantially perpendicular to the plane of rotation of said buoyant magnetic stirrer.

Claim 26

The method according to claim 22, further comprising inclining the flask to the horizontal, and rpotating the buoyant magnetic stirrer in a substantially horizontal plane while the flask is inclined.

Claim 27

The method of claim 23, wherein the placing of said medium is of an amount to partially fill the flask so as to leave a substantial space above the liquid level with the flask in the tilted position.

Claim 28

The method of claim 24, wherein the step of placing liquid medium in the flask comprises the step of placing cell culture medium in the flask.

Claim 29

The method of claim 21 or 22, further comprising placing in said flask a buoyant member comprising an impeller for causing upward flow of liquid medium.

Claim 30

The method of claim 21, further comprising providing a spherical flask, and placing in said flask a buoyant member comprising an impeller causing an upward flow of the liquid.

Claim 31

A stirrer apparatus for stirring a liquid medium in a flask comprising: (a) a flask for holding liquid medium having an opening at the top and being generally symmetrical about an axis extending through said opening, (b) stirrer means for stirring substantially all of the liquid medium in the flask comprising an element of magnetically attractable material, buoyant means for supporting said element in the liquid medium in the flask, said element and said buoyant means having a density less than the density of the liquid medium, said stirrer having a length greater than the radius and less than the diameter of the flask at the surface of liquid culture medium therein; and (c) magnetic field means for causing said stirrer means to rotate while supported in the liquid medium generally about an axis passing therethrough, said last mentioned axis being substantially perpendicular to the surface of the liquid medium and substantially at the center of said liquid medium surface.

Claim 32

A stirrer apparatus for stirring a liquid medium in a flask comprising: (a) a flask for holding liquid medium having an opening at the top and being generally symmetrical about an axis extending through said opening, (b) stirrer means for stirring substantially all of the liquid medium in the flask comprising an element of magnetically attractable material, buoyant means for supporting said element in the liquid medium in the flask, said element and said buoyant means having a density less than the density of the liquid medium, said stirrer having a length greater than the radius and less than the diameter of the flask at the surface of liquid culture medium therein; and (c) magnetic field means for causing said stirrer means to rotate while supported in the liquid medium generally about an axis passing therethrough, said last mentioned axis being substantially perpendicular to the surface of the liquid medium and substantially at the center of said liquid medium surface.

Claim 33

The stirrer apparatus of claim 28, said stirrer means being approximately half-submerged in said liquid medium.

Claim 34

The stirrer apparatus of claim 29, said stirrer means further comprising impeller means for generating an upward flow of liquid medium in said flask.

Claim 35

The stirrer apparatus of claim 28, said stirrer means further comprising impeller means for generating an upward flow of liquid medium in said flask.

Claim 36

The stirrer apparatus of claim 28 said flask having cylindrical walls, and means defining a trough in the bottom part of the flask comprising a centrally located upstanding conical portion.