PAJ SENSOR A/S has research, development and production experience with a range of sensor technologies:


  • Sensors for robotics
  • Brake sensors
  • Measurements in fluids
  • Measurements in air
  • Capacitive measurements
  • Optical measurements
  • Signal conditioning and noise considerations
  • Calibration and test of sensors




Traditionally the water content of oils has been measured using either chemicals or laboratory equipment providing a percentage (%) or as ppm (parts per million). This laboratory approach has some drawbacks:


  • The small oil sample volume may not represent the many tons of oil
  • Time will elapse before the result returns from the lab – and the damage may actually have happened before results are knows
  • The analysis are typically only conducted once or twice a month
  • Samples are highly dependent on the personnel and correct handling & storage for precise measurements
  • Many types of oil analysis state water content very inaccurately – e.g. less than 1000 ppm. In many oil types the damaging effects, however, already occur at 100 ppm


These drawbacks can be eliminated by installing PAJ Water-In-Oil sensors which will monitor the water level in the entire oil system 24/7. PAJ sensors have the highest measuring quality in the market, and are calibrated for the specific oil type. Our WIO sensors are GL and MAN Diesel & Turbo approved.


The sensor will be giving you early warnings and the ability to take preventing actions – and is thus a cheap insurance against the very costly repair and downtime costs. Repair and downtime costs in most applications range between EUR 10,000 – 200,000, and the payback on the sensor cost is thus very high – without including the commercial/customer effects in the downtime costs.


See or download our product overviews, data sheets, etc. here:

  • Product overview, Standard and Ball Valve
  • Product overview, Integrated solution
  • Datasheet WIO200

- and contact us if you need more information or help.

PAJ Group General Terms & Conditions: click here

PAJ Sensor A/S is in the market of producing and developing new sensors. PAJ Sensor A/S has developed - and is globally selling - a sensor that can detect water in oil – our so-called WIO sensor.

Surveys have documented that water or moisture is the second largest contamination (after particles) in oil systems. Water has a damaging effect on the life time of oil and system components:


  • Reduced oil film strength and lubricity
  • Corrosion
  • Hydrogen-induced fractures (embrittlement or blistering)
  • Fastened oil degradation which will speed up the oils oxidization

The effect is damages to engine parts, cylinders, bearings, etc with resulting mechanical failures and therefore repairs and expensive downtime costs (ranging between EUR 10,000 - 200,000).


Any oil can hold a certain amount of water (dissolved water) depending on the oil type and temperature - until free water is formed. Free water is what has the most damaging effects, however, the damaging effect occur already at low water activity. For optimal protection of machine components the water content should not exceed 30% of the saturation point. The amount of water a specific oil type can dissolve varies significantly, depending on e.g. the base oil, additives, oxidation, temperature and pressure.


Anywhere where there is lube oil, gear box oil, hydraulic oil, transformer oil or diesel oil, there is a  potential application of our WIO sensors:

  • Engine or oil systems: 2/4-stroke vessel engines or high speed engines
  • Gear boxes
  • Turbines - e.g. gas turbines in powerplants, hydropower or wind energy
  • Hydraulic systems
  • Transformers – water in the transformer oil can be very dangerous and is safety critical
  • Cooling/ventilation systems – keeping the cooling or vantilation systems up and running is critical
  • Pumps – especially large scale water or heat pumps
  • Compressors – large industrial air compressors in for example factories or power plants




Development of a laser based optical sensor that can measure oil contamination in compressed air with extreme accuracy.


The innovation relates to the development of a photo acoustic spectroscopy based sensor system for the detection of oils in compressed air. Oil contaminants in compressed air can be both costly and health threatening in a vast variety of industries and current sensor technologies are inaccurate, expensive and unreliable.

The sensor has been co-developed with Danmarks Nationale Metrologiinstitut (DFM) and the Dutch Metrology Institute (VSL), and it is the only sensor technology in its field with traceability to a National Metrology Standard. A well-functioning prototype has been developed, with a supreme and world leading accuracy, and the technology is in the process of being patented worldwide. The prototype is currently being matured into a market-ready product for release in 2024.


ISO9001 - ISO14001 - ISO13485 - IRIS - IEC61340-5-1 - IPC A-610 CLASS 3