Viscosity tester and method with orbiting object

An apparatus for measuring the viscosity of a fluid, said apparatus comprising:

• a receptacle for containing the fluid;
• a free standing magnetic object on surface or receptacle disposed in the fluid in the receptacle;
• magnet means for producing and imposing a magnetic force on said magnetic object and moving the magnetic object through said fluid in a generally orbital pattern in said receptacle to produce at least one parameter corresponding to the viscosity of the fluid;
• sensing means for sensing the parameter and producing a signal corresponding to the viscosity of the fluid, said sensing means having at least one position sensor for sensing the magnetic object at a sensed position as the magnetic object moves in the generally orbital pattern and repetitively producing a position signal that corresponds to the speed of the magnetic object and the viscosity of the fluid, whereby said parameter being sensed is the speed of the magnetic object;
• and
• processing means responsive to the position signal for counting each time said object passes the sensed position during a predetermined period of time to produce a count corresponding to the number of times the magnetic object completes the orbital pattern during said period of time.

A viscosity tester for fluid comprising:

• a centrally disposed chamber for containing the fluid, having a cylindrical side wall and a circular bottom wall defining a chamber said bottom wall having a perimeter at side wall junction;
• a magnetic object for being disposed in said chamber in said fluid;
• a plurality of electromagnets mounted in positions spaced around and proximate to said chamber side wall;
• a plurality of proximity sensing coils mounted proximate to said chamber bottom wall, each proximity sensing coil having a sensing field and producing a sensor signal when said magnetic object is within said sensing field, a unique one of said proximity sensors being associated with each one of said electromagnets;
• a power supply;
• a control system interconnected with said power supply, said electromagnets and said proximity sensors for selectively sequentially energizing said electromagnets, for energizing a particular one of said electromagnets in response to a sensor signal from the proximity sensor coil that is uniquely associated with the particular one of said electromagnets, for imposing magnetic forces on said object to urge said magnetic object in a generally circular path along the cylindrical side wall and proximate to said perimeter;
• and
• means for producing an output signal corresponding to the viscosity of said fluid based on at least one of said sensor signals.

A method for measuring the viscosity of a test fluid comprising:

• disposing a free standing magnetic object on a surface in the fluid;
• producing and imposing a magnetic force on said magnetic object and moving the magnetic object through said fluid in a generally orbital pattern to produce at least one parameter corresponding to the viscosity of the fluid;
• and
• repetitively sensing said parameter and producing a signal corresponding to the viscosity of the fluid,