Liquid level sensor new technology

Sensor Review

ISSN: 0260-2288

Article publication date: 1 December 2004




(2004), "Liquid level sensor new technology", Sensor Review, Vol. 24 No. 4.



Emerald Group Publishing Limited

Copyright © 2004, Emerald Group Publishing Limited

Liquid level sensor new technology

Liquid level sensor new technology

Keywords: Liquid-level measurement, Sensors

An innovative and versatile sensor has been developed by product innovation to measure liquid levels.

The optical level sensor (OLS) is unique in the fact that it measures liquid levels directly rather than interpreting an electronic signal as, for example, in capacitance, ultrasonic and magnetostrictive devices. Therefore, it will accurately measure liquids regardless of dielectric, conductivity or temperature (Plate 2).

The OLS (which can be certified intrinsically safe) is available to manufacturers for licence, and will be particularly useful to the chemical, heating and ventilating, food and drink, oil, process and water industries.

Plate 2 The optical level sensor

“This huge industry is constantly expanding. The capacitance market in Europe alone is worth over $100 m a year, but it needs a more accurate and reliable device that is attractively priced. I believe we have filled the gap in the market with our Optical Level Sensor”, comments Peter Frank, Managing Director, Product Innovation Ltd.

The OLS uses the known optical principle of total internal reflection. The new, patented technology allows this to work in a continuous probe and results in virtual analogue detection. The output is available in any of the standard formats, including digital. The electronics within the probe have the additional benefit of double checking the liquid level, giving a degree of data redundancy not previously available and allowing for self diagnosis features.

The OLS is designed in a modular form allowing customers to specify the length of probe required for their application. If appropriate, the LED/sensor pairs within the probe can be concentrated in regions of particular concern, giving high accuracy very cost-effectively. The probe has a flat base, enabling liquid levels to be measured very close to the bottom of the tank.

The probe is smooth and solid and therefore ideal to use where no moving parts and ease of cleaning are important factors. Also, because it is fully encapsulated, high-pressure applications present no problem. The resolution (down to approximates 1 mm) can be specified by the end user.

For technical information, please contact: Peter Frank at Product Innovation on 020 8452 3968 or through E-mail:

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