The demands on the fluid

The dry / wet bulb measurement is based on the evaporation of demineralised water. When fluid evaporates, energy is extracted from the remaining fluid. This extracted energy causes a temperature drop. This lower temperature is measured by the 'wet' temperature sensor inside the wick.
For the measurement, demineralised water is used because it is easy to produce. Demineralised water is water without impurities. Contaminants change the amount of energy required for the fluid to evaporate, and are therefore highly undesirable.

A major problem when using demineralised water is the wick drying out or the appearance of mucus, slime or other contaminants in the liquid, on the inside of the container or the wick.
Contaminants may be present in the water (if it is not demineralised water) or generated in the water because it is in contact with the air.

These contaminants can directly affect the evaporation process or because they accumulate in the wick, slowly change the evaporation value.
Whatever the cause is, the humidity measurement will then be wrong.

From the above, the properties of the measuring unit fluid can be derived:

  • Evaporation value must be equal to demineralised water.
  • The fluid must be effective in resolving problems in the measuring unit.
  • There may be no residues in the wick that change the evaporation value.

Aquanex and Aquanex+ Measuring Unit Fluid meet these requirements. At Nexus, during production, the quality of the products are continuously monitored. This way the professional grower has a reliable humidity measurement.

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