Flow Alarms

Platon Liquid Low Flow Alarm

For liquid low flow or flow failure alarm on cooling systems, water heaters or lubrication systems, the Platon LF flow switch is a rugged sensor with simple electrical reed switch output. Installed in a vertical line with flow upwards, normal flows lift the float in the sensor. A magnet encapsulated in the float then actuates a reed switch, giving contact closure. Should the flow drop to below the preset alarm level, the float falls to the rest position and the contacts open to give an alarm output.

The Model LF is available in 1/2” and 3/4” line sizes, with BSP female threaded connections. Alarm rates are factory set between 0.5 L/min and 10 L/min, to suit most applications. The standard unit is in brass, and has a one piece body suitable for high pressures, with no glands or seals to leak. The externally mounted reed switch has flying leads for local connection to a terminal block.

Typical applications are for water supply flow failure into heaters or boilers, where the flame or power supply is cut to prevent overheating accidents, for lubricant or cutting fluid flow failure in machine tools or gearboxes.

For flow failure alarm in cooling circuits, the LF flowswitch is used on X-ray equipment, electron microscopes, transformers, radio transmitters and high frequency generators.


  • Low cost flow alarm
  • Simple rugged construction
  • Brass,BSP connections
  • Selectable alarm trip level (factory set)
  • No glands or seals
  • Stainless Steel and other special OEM versions available
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