The technology supplied by Norcross Corporation employs the Piston Principle of viscosity measurement. In this technology, a piston assembly as described in the drawing (at right) is periodically raised by an air lifting mechanism, drawing the material being measured down through the clearance between the piston and the inside of the cylinder into the space which is formed below the piston as it is raised. The assembly is then held up for typically 20 seconds (animation at right has been set for a 10 second rise). The assembly is then allowed to fall by gravity, expelling the sample out through the same path as it entered. The time of fall is a measure of viscosity, with the clearance between the piston and inside of the cylinder forming the measuring orifice. The Norcross viscosity controller measures the time of fall and displays the resulting viscosity value.
