Electricity + Control April 2017

COVER ARTICLE

VEGA

Get Focused: Why 80 GHz radar sensors are the future of liquid level measurement

FEATURES: • Control systems+ automation • Electrical protection+ safety • Flowmeasurement • Transformers+ substations • Lighting

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3/17/2017 12:35:44PM

T he introduction of 80 GHz radar sensors represents a paradigm shift in liquid level measurement. Let’s look at all the things an 80 GHz radar sensor can do. Focused beam avoids obstructions: Increased focus of the beam angle is the principal benefit of 80 GHz radar instruments; the one improvement that makes all the rest possible. In every process, focus is crucial to accurate level measurement, and these new instruments emit the most focused signals on the market. With an antenna of the same size, 80 GHz gauges emit a beam angle of only 3°.This allows them to be used in vessels with internal installations or heavy build-up on the walls; the focused microwave beam simply avoids these obstacles as if they aren’t even there.This is welcome news in chemical and food production, where obtrusive internals are the norm and space is at a premium. An exciting benefit of increased signal focusing is the performance of 80 GHz radar sensors when mounted on ball valves. Historically, attaching a 26 GHz radar gauge to a ball valve and receiving an accurate level measurement has been a significant challenge. Ball valves contain many interior surfaces that reflect radar signals. To make matters worse, they are often used in combination with a bleed ring that can create even more signal noise. All of these reflections make it difficult to discern which signals are generated by the valve and which are from the product. This confusion forces operators to turn to instrumentation manufacturers for help, but the best solutions

are often difficult to implement and may require periods of trial and error despite the best efforts of plant technicians. Before long, the manufacturer’s tech is on site servicing the 26 GHz radar. Small antennas take radar where radar has never gone before: Amping up a radar sensor’s focus has an opposite effect on its an- tenna – its size decreases as transmission frequency increases. An 80 GHz sensor, therefore, does not require a large horn to focus its beam at the measured material.The signals take a narrow beam all on their own.The saved space makes a huge impact, particularly as it applies to retrofitting. There’s a trend in the pharmaceutical and chemical industries toward batch production. Batching allows operators to produce seasonal and low-volume products with less financial investment. Small batches are produced in small vessels, where conventional wisdom says using radar is impossible due to small process connec- tions.Thanks to the compact antenna of 80 GHz radar sensors, that is no longer true, and operators no longer have to sacrifice accurate measurement in the name of space. Enhanced resolution measures to the last drop: When the level of liquid in a vessel gets low enough, 26 GHz radar is unable to distin- guish the signal returned by the remaining product from that of the tank bottom, and the user rightly thinks the vessel is empty when it isn’t.This is the same as the action-movie computer whiz being unable to ‘enhance’ surveillance footage. Limited resolution presents a natu-

ral handicap to process efficiency. Ultra-focused 80 GHz devices measure liquid down to the last millimeter in the tank, giving users accurate data they can use to optimise their processes. It won’t thwart a terrorist attack or prevent an elaborate heist, but the enhanced resolution of 80 GHz radars sensors helps users avoid waste.

The focused beam (yellow) of 80 GHz radar sensors avoid internal agitators that contact the 26 GHz radar beam (gray).

Enquiries: VEGA

Tel. +27 (0) 11 795 3249 Email: info.za@vega.com

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