The Captrol 511 Point Level Switch is designed to be the ultimate in detecting the presence or absence of various materials from powder bulk solids to most liquids. The electronics are self contained in a cast aluminum housing pre-assembled to a rugged three element sensing probe.
Principle of Operation
The Captrol 511 responds to a capacitance change at the active section of the sensing element. The material to be detected must be referenced to ground potential to create a significant capacitance change. Typically the ground referencing is accomplished by threading the probe to a metallic tank which then becomes ground reference. Most non-metallic tanks require a ground pipe or plate adjacent to the active probe.
When material fills the space between the active probe and ground, a capacitance change is detected and the output relay is actuated.
Effects of an accumulated build-up that typically cause false signals are ignored via Delavan’s driven guard element of the sensing probe.
R.F. Capacitance Point Level Switch