GapSwitch 409 - SludgeSwitch

The ECHO GapSwitch 400 Series is a range of ultrasonic gap level switches for monitoring and controlling liquid level. Ultrasonic sound waves travel from the transmitter to the receiver through the gap. Air dissipates the sound energy. Thus, liquid is required for the sound energy to traverse the gap and activate the relay (liquid fills the gap and activates the relay). All versions are solid state resulting in years of maintenance-free operation.