Point Level Switches for Solids & Liquids

A vibrating fork or rod switch for free-flowing powders and granules up to 10 mm particle size, a rotating paddle switch for general bulk solids at lower cost, or an admittance switch if the material is sticky and would otherwise build up on a probe.

It sets whether the switch output goes to its alarm state on high level or low level, so that a power failure or sensor fault is always treated as an alarm rather than silently ignored. All Trumen switches on this page offer field-selectable minimum or maximum fail-safe.

The Seli SGS-02 capacitive switch, in 316L stainless steel and CIP/SIP cleanable up to 150 °C, and the Seli SKS and KS conductive detectors, rated IP69K for CIP/SIP cleaning. Both suit dairy, food and pharma tanks where standard switches would fail hygiene requirements.

Both sense a change in electrical capacitance as material covers the probe, but an admittance switch's circuit is designed to ignore a coating or build-up left on the probe by sticky material, while a standard capacitance switch can false-trip on heavy build-up. Choose admittance for sticky solids or liquids, and capacitance for cleaner, non-sticky material.

Yes. Besides a point level in a vessel, the vibrating fork switch can detect flow or no-flow of liquid in a pipe, useful as a dry-run or pump-protection interlock. It handles liquids up to 10,000 cP and temperatures up to 250 °C.

A conductivity switch: the Trumen LWS or the Seli SKS-15, SKS-25 and KS-17 detectors, which sense current flow between an electrode and the vessel wall through the liquid. They only work on liquids conductive enough to carry that current, so they aren't suitable for oils or deionised water.