Level Sensors and Pressure Gauges

APG float switch technology comes in many different forms. The two most common are stem float switches and cable suspended float switches. Stem float switches offer more switch points and a higher maximum operating temperature. Cable suspended float switches are maintenance free and easy to use.

Our most popular float switch is the KA series float, and is cable suspended. Widely used in basic process control across several industries, most notably the Water & Wastewater industry, it is easy to install, easy to use, and has no external moving parts for zero maintenance.

The KA series cable suspended float switches work via internal mechanical switches that activate or deactivate based on the tilt angle of the float. Specific tilt angles are achieved by attaching a weight to the cable. This acts as a pivot point for the float. Distance between switch points depends on the length of cable between the float and the weight.

Because the switches are inside the float, the KA series are ideal for use in dirty, harsh applications, such as wastewater. Older versions used switches containing a small amount of mercury, however, this practice has changed and no mercury is present in today’s models.

Stem float switches, similar to resistive chain technology, use a magnet inside the float to open and close reed switches inside the stem, or rod. However, our stem float switches are a point level, rather than a continuous level, means of measurement. They feature up to seven floats in a fixed position along the stem that float only a short distance, enough to activate the switches inside the rod.

Float switches are a simple means of measurement, with a high degree of reliability and consistent accuracy. They are good for vaporous liquids or in heavy foam where non-contact sensors may have difficulty. Cable suspended floats are great for applications where build-up may impede a stem float, such as in wastewater. Stem float switches work in tight spaces, while cable suspended float switches require room to operate.

However, float switches are not a continuous means of measurement, and may not be the best choice where real-time level data is desired. Refer to ultrasonic, magnetostrictive, resistive chain, and submersible pressure for continuous level measurement, and advanced decision making and control.

We want to help you know if a float switch is right for you. The following should be discussed with an APG application engineer to ensure successful performance:

• Specific gravity of the float
• Applications with heavy build-up
• Operating temperature from 140 F to 300 F
• Compatible with any chemicals present
• Max and Min switch differentials

Please contact APG at sales@apgsensors.com, (888) 525-7300, or via live chat to discuss your application.