HUMIDITY-SENSOR STANDARD
Application area
High concentration of water can cause severe disturbance in operation and damage the engine and the auxiliary diesel for example. In laboratories, the absolute water content is defined in ppm (parts per million), but the saturation limit of the oil can be determined by relative humidity measurement. This has the advantage that it is not necessary to know the saturation limit in order to determine if there is free or dissolved water. The relative humidity is calculated intern at a reference temperature of 40 °C to ensure comparability.
High concentration of water can cause severe disturbance in operation and damage the engine and the auxiliary diesel for example. In laboratories, the absolute water content is defined in ppm (parts per million), but the saturation limit of the oil can be determined by relative humidity measurement. This has the advantage that it is not necessary to know the saturation limit in order to determine if there is free or dissolved water. The relative humidity is calculated intern at a reference temperature of 40 °C to ensure comparability.
Example:
- Mineral oils (e. g. HLP) have a comparatively low water absorption capacity. 500 ppm may signify that the oil is over-saturated and fee water exists.
- Ester oils (e.g. HEES) have a relatively high water capacity. 500 ppm may show that the oil is just saturated by 15%.
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Technical Features:
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Note: Warm oil can absorb more water than cold oil. Therefore the relative humidity of the oil increases in case of no further water supply. Hot, relatively dry oil may suddenly contain free water if the ambient temperature cools down. The Humidity Sensor Standard points out the current saturation of the oil with water, independent from the temperature and oil type. Additionally it assures the operation of the system by direct warning. The sensor is ideal to use for small pipe diameters because of its depth of immersion of 29 mm, only.