What is a capillary rheometer?
A rheometer is an instrument used to measure rheological properties like shear stress, shear rate, and shear viscosity. Capillary rheometry is a technique whereby a sample undergoes extrusion through a die of defined dimensions and the shear pressure drop across the die recorded at set volumetric flow rates.
A capillary rheometer is a specific type of rheometer which computes rheological parameters from pressure measurements taken prior to the flow of material through a small capillary. The rheometer typically uses a speed controlled piston to drive material from a heated bore through a small (1mm diameter typically) capillary. Pressure measurements are made at each piston speed using diaphragm transducers in the bore prior to entry of the capillary die.
