Magnetic mixer

Claim 2

A mixer for agitating a fluid in a vessel, the mixer comprising: a vessel fitting having inner and outer surfaces for defining a generally cylindrical member extending into the vessel and having a longitudinal axis such that the outer surface of the vessel fitting is located within the vessel; an agitator comprising: a hub for fitting over the outer surface of the vessel fitting and rotatable with respect to the vessel fitting; a plurality of agitator magnets disposed circumferentially about the hub; means extending from the hub for agitating the fluid; and a first pair of inwardly facing bearing surfaces spaced from one another on the hub; a pair of bearing rings having a second pair of bearing surfaces for cooperating with the first pair of bearing surfaces, the pair of bearing rings for encircling the outer surface of the vessel fitting and able to move longitudinally along a portion of the outer surface of the vessel fitting; and driving means within the vessel fitting for magnetically coacting with the plurality of agitator magnets and causing the agitator to spin about the longitudinal axis within the vessel and levitate along the outer surface of the vessel fitting.

Claim 3

The mixer of claim 1 wherein the driving means comprises a plurality of drive magnets for rotating about the longitudinal axis.

Claim 4

The mixer of claim 2 wherein the driving means further comprises a motor for rotating the drive magnets about the longitudinal axis.

Claim 5

The mixer of claim 2 further comprising an even number of agitator magnets sealed within the hub and an even number of drive magnets, wherein the agitator magnets are arranged such that adjacent agitator magnets face toward the longitudinal axis with alternating north and south poles, and the drive magnets are arranged such that adjacent drive magnets face away from the longitudinal axis with alternating north and south poles.

Claim 6

The mixer of claim 1 wherein the vessel fitting extends upwardly from a bottom wall of the vessel.

Claim 7

The mixer of claim 1 wherein the first pair of bearing surfaces is removably attached to the hub.

Claim 8

The mixer of claim 1 wherein the outer surface of the vessel fitting defines at least one longitudinal flat, and each of the bearing rings includes at least one internal flat for mating with the at least one longitudinal flat and for preventing rotation of the bearing rings about the vessel fitting.

Claim 9

The mixer of claim 1 wherein the hub includes a plurality of radial holes for promoting circulation of fluid between the hub and the vessel fitting.

Claim 10

A mixer for agitating a fluid in a vessel, the mixer comprising: a vessel fitting having inner and outer surfaces for defining a generally cylindrical member extending into the vessel and having a longitudinal axis such that the outer surface of the vessel fitting is located within the vessel; an agitator comprising: a hub for fitting over the outer surface of the vessel fitting and rotatable with respect to the vessel fitting, the hub having a top and a bottom; a plurality of agitator magnets sealed within and spaced circumferentially about the agitator; means for agitating the fluid; a first bearing surface located toward the top of the agitator and above the hub magnets; and a second bearing surface located toward the bottom of the hub and below the hub magnets; first and second bearing rings with corresponding third and fourth bearing surfaces for cooperating with the first and second bearing surfaces, the first and second bearing rings being in longitudinal sliding engagement with a portion of the outer surface of the vessel fitting; and a plurality of drive magnets rotatably mounted within the vessel fitting for rotating about the longitudinal axis in order to create a rotating magnetic field for engaging the plurality of agitator magnets and causing the agitator to spin about the longitudinal axis within the vessel and for magnetically levitating the agitator along the vessel fitting.

Claim 11

A mixer for agitating a fluid in a vessel, the mixer comprising: a vessel fitting having inner and outer surfaces for defining a generally cylindrical member extending into the vessel and having a longitudinal axis such that the outer surface of the vessel fitting is located within the vessel; an agitator comprising: a hub for fitting over the outer surface of the vessel fitting and rotatable with respect to the vessel fitting, the hub having a top and a bottom; a plurality of agitator magnets sealed within and spaced circumferentially about the agitator; means for agitating the fluid; a first bearing surface located toward the top of the agitator and above the hub magnets; and a second bearing surface located toward the bottom of the hub and below the hub magnets; first and second bearing rings with corresponding third and fourth bearing surfaces for cooperating with the first and second bearing surfaces, the first and second bearing rings being in longitudinal sliding engagement with a portion of the outer surface of the vessel fitting; and a plurality of drive magnets rotatably mounted within the vessel fitting for rotating about the longitudinal axis in order to create a rotating magnetic field for engaging the plurality of agitator magnets and causing the agitator to spin about the longitudinal axis within the vessel and for magnetically levitating the agitator along the vessel fitting.

Claim 12

The mixer of claim 9 further comprising a variable speed motor for rotating the drive magnets about the longitudinal axis.

Claim 13

The mixer of claim 9 further comprising N pairs of agitator magnets and N drive magnets, N being an even integer, wherein the pairs of agitator magnets are arranged such that adjacent pairs of agitator magnets face toward the longitudinal axis with alternating north and south poles, and the drive magnets are arranged such that adjacent drive magnets face away from the longitudinal axis with alternating north and south poles.

Claim 14

The mixer of claim 11 wherein N equals 6.

Claim 15

The mixer of claim 9 wherein the first and second bearing surfaces are removably attached to the hub.

Claim 16

The mixer of claim 9 wherein the outer surface of the vessel fitting defines at least one longitudinal flat and the first and second bearing rings each include at least one internal flat for mating with the at least one longitudinal flat and for preventing rotation of the bearing rings about the vessel fitting.

Claim 17

The mixer of claim 9 wherein the hub includes a plurality of radial holes for promoting circulation of fluid between the hub and the vessel fitting.

Claim 20

The system of claim 16 wherein the driver comprises: a plurality of drive magnets for rotating about the rotational axis; and a motor for rotating the drive magnets about the rotational axis.

Claim 21

The system of claim 17 wherein the third and fourth bearing surfaces are removably attached to the hub.

Claim 22

The system of claim 17 wherein the agitator magnets are sealed within the hub.

Claim 23

The system of claim 17 wherein the third bearing surface is on a first side of the agitator magnets and the fourth bearing surface is on a second side of the agitator magnets opposite the first side.

Claim 24

The system of claim 17 wherein the hub includes a plurality of radial holes for promoting circulation of fluid between the hub and the drive housing.