Gladiator pump protection switches from Hawk Measurement Systems work by means of a sensing probe which forms one plate of a capacitance circuit. The vessel wall makes up the second plate and the dielectric constant of the product between this probe and the vessel wall causes a change of capacitance as the level approaches the probe. This change is then detected, amplified and used to switch a relay for indication or control purposes.
A special circuit is used in these pump protection switches to ignore product build up between the probe, or active element, and the guard as well as between the guard and the vessel wall. These switches have immunity to build-up and can monitor material with a variety of dielectric constants.
These means that these protection switches can be used with a wide range of liquids. They can also be used in applications where pipe or wall mounting with minimal protrusion is required and to detect the presence of liquids to ensure the pump will never run dry.