MMT162 Compact Moisture in Oil and Temperature Transmitter for OEM Applications

The Vaisala HUMICAP® Moisture and Temperature Transmitter for Oil MMT162 is an excellent economical solution for reliable on-line detection of moisture in oil.

  • Compact, accurate and economical
  • Proven Vaisala HUMICAP® technology
  • Continuous measurement of moisture in oil
  • Excellent pressure and temperature tolerance
  • Compatible with the Vaisala MI70 indicator

MMT162 Compact Moisture in Oil and Temperature Transmitter for OEM Applications 

Operating Principle

The Vaisala transmitters used for measuring moisture in oil feature the HUMICAP® sensor, a capacitive thin-film polymer sensor especially developed for demanding moisture measurements in liquid hydrocarbons. The HUMICAP sensor consists of four functional layers: glass substrate, lower electrode, water-active polymer layer, and porous upper electrode.

The thin-film polymer either absorbs or releases water as the surrounding moisture level changes. Water molecules move to/from the polymer layer until there is moisture equilibrium between the polymer and the oil. The dielectric properties of the polymer depend on the moisture level. As the moisture level changes, the dielectric properties of the polymer film change, and so does the capacitance of the sensor. The instrument’s electronics measure the capacitance of the sensor and convert it into water activity. Oil molecules or additives do not penetrate the electrode. Thus the sensor output is independent of the oil type.