Float Switch Level Measurement

Float Switch Level Measurement

Float switch level measurement is a mechanical point-level method in which a buoyant float follows the liquid surface. The float’s position is detected by an internal sensor or mechanical linkage, producing a discrete switching output when the level reaches a defined threshold. The result is a clear, deterministic high/low indication without complex signal processing.

The primary benefits are simplicity, low installed cost, and predictable behavior in appropriate liquids. With proper construction, float switches can deliver long service life and straightforward troubleshooting, making them a practical choice for basic alarms, pump control interlocks, and protective shutdowns where continuous measurement is not required.

Application suitability depends on liquid density, viscosity, and the presence of solids or fibrous material that could hinder float motion. Mounting orientation, turbulence, and wave action should be considered to avoid chatter at the switching point. Material compatibility with the wetted components and any required hazardous-area interface (e.g., NAMUR signaling) are also central to correct specification.

Common applications include pump protection in lift stations and sumps, high-level alarms in open basins, and general point level control in tanks and vessels across water and wastewater facilities. They are frequently used where access is easy and where the process liquid is sufficiently clean to avoid mechanical fouling.

Float switches integrate directly to discrete inputs, relays, and pump control panels with minimal configuration. When used within their mechanical and process limits, they provide an effective and easily understood layer of level protection for utility and general liquid services.

Field Instruments & Controls, Inc. an exclusive authorized representative of sales and service for Endress+Hauser.