Orthogonal Superposition Rheometer

摘要

An orthogonal superposition rotational rheometer that applies a rotational torque and an orthogonal axial oscillatory stress to a fluid. The rheometer uses a cylindrical bob in a double wall cup to apply shear rotational and axial forces to the fluid. Openings in the top section of the cylindrical bob reduce surface tension effects on the force measurement. Fluid pumping effects at the bottom of the rheometer's double wall cup are minimized by openings in the inner wall of the double wall cup that allow fluid to be displaced when the bob moves downwards.

主权项

1. A rotational rheometer comprising:
a double wall cup having an inner cylindrical wall and an outer cylindrical wall forming an annular chamber and a central cylindrical chamber; a cylindrical bob having a top disk portion, a hollow cylindrical portion and a shaft attached to the center of the top disk portion; a motor coupled to the double wall cup configured to rotate the double wall cup; a transducer coupled to the cylindrical bob configured to impose axial oscillations on the cylindrical bob; wherein the inner wall of the double wall cup comprises openings at its lower end that allow fluid communication from the annular chamber to the central cylindrical chamber; and wherein the cylindrical bob has apertures just below its top disk portion that circumscribe a substantial portion of the circumference of the top disk.