Liquid level sensors detect interfaces or liquid levels between liquids like water and oil or solid and liquid interfaces. These liquid level sensors are often used in different liquid container monitoring applications including furnaces and heaters, flow line monitoring as well as in other automotive applications, household appliances and control technology.
Different types of liquid level measurement technologies are available including sonic / ultrasonic, optical, pressure membrane, microwave / radar, differential pressure sensing, electrical resistance / conductivity, air bubbler, magnetic / mechanical floats, tuning / vibrating fork, rotation paddle, radio frequency and RF / capacitive admittance.
These level measurements are generally indicated by activating or deactivating an electronic switch like a relay, reed or a solid state switch. Electrical resistivity and conductivity liquid level sensors utilise a low-voltage power source that is generally applied across separate electrodes. A conductive liquid like water or chemical contacting both probes complete the conductive circuit.
Electrical resistance or conductivity is generated when the liquid contacting from both probes complete a conductive circuit. In the majority of cases, the vessel or tank is included in this circuit. The signal can be transmitted to a process controller where the set points have been programmed to close or open valves, and / or to initiate other fluid processes.
Magnetic or mechanical floats are generally used with liquid level sensors. These liquid level sensors can be placed at different points to determine the flow or level of the process liquid. Liquid level sensors are generally used in fuel level measurement applications.
