A NOVEL DESIGN TO ELIMINATE END EFFECTS IN A CONCENTRIC CYLINDER VISCOMETER

Novel designs and procedures have been developed which greatly reduce the end effects in a concentric cylinder viscometer. The essential features of the most versatile design are a hollow inner cylinder, open at both ends, conterminous inner and outer cylinders, and a pool of mercury at the bottom of the cup which essentially eliminates the torque exerted on the bottom of the inner cylinder and on the sample in the gap. The method promises to be particularly suitable for rather viscous, non-Newtonian fluids, including those with an appreciable yield stress. Existing viscometers can be readily modified to implement these ideas.