Level switches are often used for detecting interfaces between liquids, or to determine powder and liquid levels. These level measurements are often indicated through an electrical switching action. The point level switch measures the level of a container that has gone over or reached a pre-determined point.
The switching mechanism is vital for continuous level switches. The multiple point switches can also be incorporated together to offer a stepped version at a constant level. The level switches can be used as control switches or as alarm devices to turn something off or on, like sending signals to a valve actuator or pump.
Technologies used for measuring include;
• Air bubble technology
• RF or capacitive admittance
• Electrical resistivity or conductivity
• Differential pressure
• Pressure membrane
• Optical units
• Magnetic or mechanical floats
• Radio frequency
• Sonic or ultrasonic
• Tuning fork or vibration
Types of level switches
Level switches have a switched output that can either be solid state, electromechanical state, normally closed or normally open. Options for throws and poles are also available. Most level switches either have one or two throws or poles. Some manufacturers even produce custom level switches for specialised applications.
When purchasing a level switch, you need to consider the measuring range that it offers. The ratings for voltage or current of the level switch are also an important consideration. Depending on the application requirements, level switches can be mounted in many different ways. Level switches can be mounted on the side, top or the bottom of the container that holds the substance which is to be measured.
