Principle of operation

The Stealth Electronics aspirated screen RH% consists of two matched temperature sensors. One of the sensors is in free air (DRY) and the other sensor (WET) is covered with a cotton wick with other end of the wick dips into a small water container. As the air movement across these temperatures sensors is forced across via a miniature fan. The air past over the sensors causes evaporation to occur on the wet sensor. This evaporation also cools the temperature of the wet sensor. By using this difference between these two temperature probes the system can calculate the actual relative humidity. This RH% reading will be displayed on the control system. This principle is based upon the Whirling Hydrometer. These types of sensors are typically used in potato stores and in the monitoring of mushroom sheds. For most other applications the electronics RH% sensor is more typically used. The internal water reservoir typically needs to be re filled with distilled water every 2 weeks.

The working range of the Aspirated screen RH% sensor is 0-100%. Its design allows the sensors to be in high humidity for extended periods of time without the sensors becoming saturated.
An in line waterproof connect allows for easy of maintenance. Method of attachment to the building is via a metal chain. This allows for the sensor to be placed directly where the actual RH% measurement is required.