The term "Houillon" refers to the capillary tube used to measure viscosity. The method was developed in France primarily for use in lubricant blending facilities and research laboratories.
Infrared optical sensors time the sample as it passes through the tube. Each tube is fitted with an automatic cleaning system. Programmable cycles of solvent flushing and purging followed with a drying cycle are started automatically when the measurement is complete. Results are displayed on the monitor and printed.