Optical Level switches

An optical level switch works by emitting a beam of infrared light
within a prism and measuring the amount of light received. When
the measured fluid reaches the sensor the amount of emitted light
received drops thus triggering the contacts. As the sensor is
detecting the state between material covering or not covering the

prism it can be used to detect the presence or absence of fluid
thus preventing damage to pumps.
The compact unit houses the infrared transmitter, the prism, the
receiver and the electronics, there is also an external LED indicator
to show the condition of the switch. The sensor requires a power
supply of between 10-28 Volts Dc. The benefit of the modern optical
sensor is that there are no moving parts that can retain material
and get clogged up or damaged, simply fit and forget