Flow switches are particularly useful for pump protection or to activate flow or no-flow alarms. 

The DFS 5.1 Doppler Flow Switch is designed to give basic process control for pipe flow measurement, recommended for difficult liquids including wastewater, cooling water, slurries, sludge, chemicals, viscous liquids, and abrasives that would usually damage contacting Doppler flow switches. 

The non-contacting ultrasonic sensor mounts to the outside of metal or plastic pipes, without the need to cut the pipe or shut down the flow of your process, increasing your efficiency and ultimate profitability. 

With no maintenance required for the Doppler flow switch, it works on any pipe diameter 12.5 mm (0.5 in) or larger and installs in just minutes. 

The relays in the DFS 5.1 can be set to turn ON and OFF at any flow rate between 0.075 m/s to 3 m/s (0.25 ft/s and 9.8 ft/s) in addition, the end-user could inset two links for separate ON/OFF set points or just one link for a high or low flow alarm.