The device of a robust design is meant especially for precautional maintenance of systems with an oil content. The water content in oil is determined by measuring water activity and oil temperature and calculated using coefficients for temperature dependent water-in-oil solubility equation.

 

Water activity is independent on the oil type, age and temperature. Its value indicates the relative condition of current moisture level in oil to maximum possible level of water bound in the oil. The value 0 % means that oil does not contain any water. The value 100 % means the maximum saturation of water in oil and that a presence of free water is possible (so called emulsified water). The device is not designed to measure the emulsified water in oil.