Liquid level sensor meets repeatability requirements in sticky monitoring applications

Los Angeles, CA. Using highly viscous materials in manufacturing processes can become a sticky situation in more ways than one. Clogged float mechanisms, blocked fill ports, masked windows, and solid material buildup on moving floats often result in sticking floats and frozen outputs along with inaccurate readings and costly maintenance and downtime.

Gill Sensors & Controls Ltd. said it recently met the challenging level-sensing requirements for a varnish manufacturer. During the varnish-manufacturing process, plant engineers had problems with being able to reliably measure the level of lacquer in their bulk containers because of its high viscosity and sticky characteristics. Reliability was affected by the tip of the sensors gumming up and providing a false reading. The manufacturer sought a new sensor solution that could provide a reliable alert when the lacquer level dropped to 25% capacity. At that level, the containers could be topped-off with additional lacquer to prevent empty containers halting the production process.

Gill’s new high viscosity liquid level sensor Model 7014 met these requirements by means of its proprietary conductive technology specifically designed for monitoring highly viscous (water based) liquids. The 7014 sensor features an electrically sensitive probe surface and no moving parts or floats. With this design, there is nothing to wear, freeze, or clog, allowing for a reliable signal reading while at the same time reducing maintenance costs.

The probe also features a wetted area manufactured with FEP (fluorinated ethylene propylene) that has excellent nonstick properties. The smooth sensing surface can differentiate between being immersed in thick liquids versus air (the airspace at the top of the tank or container). The variance between these two readings is used to calculate true liquid level.

“Gill’s 7014 sensor technology allows engineers to ‘install it and forget it,’” said Paul Cain, manager of business development for Gill Sensors North America. “The unique profiling software calibrates each tank or container to obtain gauge readings where a ½-tank indication truly means 50% of actual level.”

The 7014 sensor can be used for level monitoring in water-based paint solids, lacquers, and pulp products along with other aggressive water-based cleaning chemical combinations commonly used in industrial processing. Even in extremely syrupy and sticky viscous materials, a simple service of wiping the probe clean using alcohol will reset the device for re-use.

The 7014’s sensor can be mounted in a ‘”bottoms up’” or inverted orientation with no impact on accuracy. The sensor is available with all of the common electrical outputs including resistive 10 to 180 Ω or 240 to 33 Ω, analog voltage output with both 0.25- to 4.75-VDC and 0.25- to 10.0-V versions, and current output with 4 to 20 mA. Easy-to-use GUI software includes a programmable switch function (output) that triggers an alarm or warning when the container or tank level has reached the user’s preselected point.