Schmidt Technology has added SS 20.400 flow sensors and their SS 23.400 ATEX counterpart to its product portfolio, which can detect very small air flows down to 0.05m/s and their direction.
Installed additionally for pressure measurement, the bidirectionally working flow sensors can reliably detect the existing overflow in cleanrooms or clean areas. If backflows take place, resulting in contamination, this is also reliably detected.
Upon request, Schmidt, which is based in St Georgen, Germany, will supply the sensors with high-precision adjustment, which provides a further improvement in the accuracy through an increased number of adjustment points and documentation of the nominal and actual values as an ISO calibration certificate. The measuring accuracy is ±1% of the measured value plus 0.04m/s.
For laminar applications, the sensors are now adjusted in a vertical flow channel. The setup guarantees a falling air flow, as ideally required in practical application, and excludes all external influences from actual measuring practice. This also takes into account the so-called thermal convection flow, which in practice amounts to about 10% of the downdraft flow of 0.45m/s.
The SS 23.400 ATEX version for use in hazardous areas meets the ATEX Directive 94/9/EC. The flow sensors are DEKRA-certified and can be used in Zone 2 (device category 3G) without any additional measures, such as a zener barrier.
