Ronald A. Buchanan

When liquid level switches are used in high-reliability applications, such as aircraft, submarines, nuclear power plants and medical equipment, it is essential that they operate with precision and dependability. Therefore, great care must be taken in choosing the best level-sensing switches to fit each specific application. With many choices available in terms of switch style, size and material, knowledge of several scientific principles related to fluids is valuable during the float switch selection process.

Click here to download this Level Advice as a printable PDF file (120k).

One of the most common level-sensing switches used in industrial applications is the float switch. It consists of a float holding a magnet and a dry reed switch encapsulated within a stem. As the float follows the level of liquid in the vessel, the magnet also moves up and down. The magnet activates the reed switch when they're both at the same level, providing an "on" or "off" signal. The signal can be conditioned to activate alarms and controllers or complete a circuit that turns on pumps to fill a tank.

Before specifying the liquid level switches necessary for a project, the customer must know the fluid being monitored. Characteristics of the liquid such as its turbulence, specific gravity, temperature and viscosity usually dictate essential switch characteristics. The liquid could also be a strong acid or base, which would influence material selection.

• Click here to learn about Liquid Level Switch Applications and Terminology.
• Click here to learn about Liquid Level Switch Materials and Requirements.

Contact Madison today to learn more about our liquid level float switch offerings!