The quick-acting specialists for increased operating safety in the cleanroom – with integrated direction detection

Increasing safety through flow measurement
Defined overpressures ensure process safety in cleanrooms through overflow from one room to the other. This overflow is usually monitored indirectly via pressure sensors. When doors or airlocks are opened, the pressure often falls below the desired operating limit of the pressure sensor, thus indicating no overpressure. In this phase, the cleanroom operator has no information (measured values) on the actual overflow. However, a backflow can be present and, consequently, contamination may be introduced. This will not be noticed despite a correctly performed pressure measurement. This can be improved in order to considerably increase the safety of the cleanroom.

Increasing operating safety with the bidirectional SCHMIDT® Flow Sensor SS 20.400 and SS 23.400 ATEX
These flow sensors not only measure the actual overflow from one room to the other but also detect the direction as an actual signal. This allows simple and consistent monitoring of all clean areas, including local cleanrooms (cleanmachines). The additional measured flow values also make it possible to release batches more easily. The flow sensor is able to measure even very small air flows down to 0.05 m / s. This corresponds to a pressure difference of approx. 0.01 Pascal! The direction of flow can be easily integrated into the existing monitoring, e.g. as a switch signal or analog signal. The sensor has no moving parts and, due to its all-metal construction, a GMP-compliant design, which guarantees complete cleanability. When used in cleanmachines, the sensor is also suitable for laminar-flow monitoring, due to its characteristics and easy mounting. The ATEX-version SS 23.400 (category 3G, Zone 2) is ideal for potentially explosive areas. And one more thing: Reducing overpressures, especially during production downtimes, allows savings in energy costs while maintaining and extending safety aspects.

Measuring accuracy in black and white
Upon request they will be supplied with an additional high-precision calibration system. This system enhances the precision even more by the use of more calibration points, and the documentation of the target and actual values as ISO calibration log. Upon request, the sensor is adjusted and calibrated for application as “laminar- flow sensor“ on ceiling diffusers in a unique “vertical flow channel“. This offers the advantage that effects from the mearurement steps on site are eliminated and highest precision will be achieved. The renowned laser doppler mearurement process (LDA) is used as reference measurement process.