What are float switches and how are they used?

What are float switches and how are they used?

As we’re in a niche manufacturing market and most of our friends don’t know what we do we thought we write about our different product offering and their usage. Hope this helps define what it is we do. Here’s article #1 – what are float switches and how are they used?

A float switch is a device used to detect the level of liquid within a tank. The switch may be used in a pump, an indicator, an alarm, or other devices.

Float switches range from small to large and may be as simple as a mercury switch inside a hinged float or as complex as a series of optical or conductance sensors producing discrete outputs as the liquid reaches many different levels within the tank. Perhaps the most common type of float switch is simply a float raising a rod that actuates a microswitch.

A common application in residential use is in sump pumps and condensate pumps where the switch detects the rising level of liquid in the sump or tank and energizes an electrical pump which then pumps liquid out until the level of the liquid has been substantially reduced, at which point the pump is switched off again. Float switches are often adjustable and can include substantial hysteresis. That is, the switch’s “turn on” point may be much higher than the “shut off” point. This minimizes the on-off cycling of the associated pump.

Two Stage Switch Float Switches

Some float switches contain a two stage switch. As liquid rises to the trigger point of the first stage, the associated pump is activated. If the liquid continues to rise (perhaps because the pump has failed or its discharge is blocked), the second stage will be triggered. This stage may switch off the source of the liquid being pumped, trigger an alarm, or both – this is based on the need of the end user.

As the needs from float switches on a commercial level vary greatly based on the independent need of the end user there is a great need for custom made float switches. FPI Sensors makes custom float switches for customers all over the world and for clients ranging from one off home based engineers to international corporations that need 1000’s of custom float switches.