Liquid flow switches with magnetic mechanism
Published: 13 January 2012 - Heather Ramsden
The FSW300 Series is a new trim to size liquid flow switch, suitable for pipe diameters from 20 to 200mm. It is available in a low maintenance Brass construction with a pressure rating of 25bar.
This field installable switch has a single Noryl blade with marked notches showing the pipe diameters and is easily trimmed to size. There is no mechanical movement transmitted from the paddle to the switch mechanism and the reed switch is activated through a stainless steel membrane by a magnet at the top of the blade. However, to prevent spurious pulses the permanent magnet used for activating the switch is opposed by a second fixed magnet. This also gives a snap action effect normally associated with mechanical units.
With a useful life of up to 100,000,000 switching cycles the magnetic design is highly repeatable with an instant response. The economical construction is considerably more stable in the long term and much less sensitive to pressure peaks.