Level Detection Based on Frequency Sweep Technology

With the FlexLevel Switch 4101 Baumer (Denmark) presents a new sensor which is based on frequency sweep technology. The device detects the level of liquids, viscous fluids and dry media. Due to the smooth, very small sensor head even adhesive media don’t stick whereby the adhesion error is very low. The level switch is suitable for overfill protection, low level detection, dry running protection and phase separation. It can be installed in any position and even at points difficult to access. The FlexLevel Switch 4101 can be easily configured on PC via the FlexProgrammer 9701. 

A frequency is swept by the transmitter and becomes subject to a phase shift depending on the media. When in contact with the media having a different dielectric constant (DC) outside the selected DC range, an electronic switch is triggered. The high sensitivity over a large sensing range from DC 1.5 up to more than 100 allows the level detection of all kinds of powders, granulates and liquids. Even difficult substances like polyamide granulate or paper can be detected reliably. Thanks to the teach-in function, the switching point is adjustable even for sticky media.

Compared to other measuring methods, this technology has important advantages: It has no vibrating parts, is soundless and not sensitive to changes based on conductivity. Even with the formation of foam, the level switch only reacts after the actual DC-value has been reached. Hence, the FlexLevel Switch 4101 is a cost-efficient and reliable alternative for applications which previously used vibration forks, conductive ultrasonic or optical sensors.

The FlexLevel Switch 4101 is mounted in a stainless steel housing making it extremely robust and corrosion-resistant. It can be mounted and sealed easily by use of a Teflon tape. The device can be used for the limit level detection in filling, storage and buffer tanks, for dry running protection of pumps, and for phase separation with oil-water mixtures in wastewater plants. The level switch is suitable for all water treatment applications as well as for all other non-food industries. Due to its fast response time of just 0.1 seconds, the sensor offers reliable level detection even with fast filling processes. In its standard version, the level sensor is available with G½”, G3/4” and G1” process connections with M12 plug or solid cable electrical connection. Other process connections are available on request as well as different housing materials.