In clean rooms the concentration of airborne particles must be as low as possible. This is done through a high rate of air change. In clean rooms of the category A, in which the product lies open and comes into direct contact with air, the aim is therefore to ensure a continuous low-turbulence displacement flow. For the monitoring of these low-turbulence displacement flows, flow sensors are used. Good manufacturing practices (GMPs ) in clean rooms stipulate closely specified, permissible work area for the flow speed of 0.45 m/s with a permissible deviation of ±20 %, corresponding to 0.09 m/s. Specifically designed for clean rooms pursuing GMP, the SS 20.415 air flow sensor from SCHMIDT Technology offers a measurement precision of 0.05 m/s. It has smooth surfaces without undercuts, allowing it to be easily cleaned or disinfected. Featuring stainless steel tube, it is resistant to common cleaning agents and disinfectants such as alcohol, peracetic acid and hydrogen peroxide. In case the sensor is contaminated it issues a 2 mA signal as opposed to outputting measurement values as a fault-insensitive 4 to 20 mA signal with high linearity. Electronics is integrated in the sensor tube, with a 9 mm diameter, that does not create any turbulence in the flow of air. Two variants are available; a version curved in a 90° can be installed directly under the ceiling of the clean room and the straight version is suitable for installation on a wall.
Edited by: Teoman Tugsuz
