SMAC   Gas rate measurement On line measurement Short measurement time (2 minutes)   AERATION MEASUREMENT SYSTEM BY COMPRESSIBILITY The SMAC™ measurement system measures aeration by its compressibility (IFP License). It is able to measure the volumetric gas ratio of a gas-liquid mixture. The main use of SMAC™ is the measurement of aeration rate of an engine oil. It is an essential parameter to quantify the presence of air in engine oil. The air significantly increases oil compressibility and therefore degrades its use in hydraulic flow. The principle of measurement is based on the difference of compressibility between a gas and a liquid.