What is a level switch and what is it used for
A level switch is a device for point level detection: it does not measure how much liquid is in a vessel, but signals that the liquid has reached a certain height. It is used for automatic pump control (filling and emptying), high level alarms and overfill prevention, dry-run protection for pumps and leak alarms in bilges and chambers. For continuous level measurement, hydrostatic probes and level transmitters are used.
How a magnetic float level switch works
A float with a built-in permanent magnet moves with the liquid level. When it reaches the height of the reed contact in the switch housing, the magnetic field opens or closes the contact. The liquid never comes into contact with electrical parts, so the switch is reliable, tolerant of contamination and suitable for hazardous areas. The magnetic contact needs no external power, and a hysteresis of around 10 mm prevents the signal from chattering when the surface ripples.
Products in the Fadip range
The ERH-xx-20 magnetic level switch has a detection level of 50 to 1000 mm, 0.5 A or 1 A contact output, aluminium or 316 stainless steel housing, working pressure up to 10 bar, medium temperature up to 80 °C, ATEX and IECEx certification and IP68 protection.
The ERH level switch is the version for demanding processes: pressure up to 40 bar, medium temperature up to 250 °C, length up to 680 mm, 20 mA or 10 V output, ATEX and IECEx and IP66/IP68 protection.
The ERH-11-20 bilge level switch in 316L stainless steel is designed for ships, bilges and other harsh environments, for pressures up to 12 bar and temperatures from -25 to +80 °C, with IP68 protection.
How to choose a level switch
Define the mounting method (side mounting through the vessel wall or top mounting through the cover), the detection height and number of switch points, the medium (its density must be sufficient for the float to float), the pressure and temperature in the vessel, the output type (volt-free contact or 20 mA or 10 V signal) and whether an ATEX version is required. For aggressive media and outdoor installation, choose a stainless steel housing.
Applications
Level switches are used in shipbuilding (bilges, fuel and ballast tanks), water supply and sewerage (chambers and pumping stations), boiler houses (feedwater and condensate tanks), the chemical and oil industries (tanks in hazardous areas), hydraulic power units and compressor stations.
Alongside level switches we offer level transmitters, digital indicators and pressure gauges.
For a quotation, send us the medium, mounting method, detection height, pressure, temperature, output type and hazardous area classification. Our technical team will recommend a suitable solution within 24 hours. Contact us.
