Level measurement has been defined in simple terms as the interface between different phases, in whatever pairing of solid, liquid and/or gas.
But, when it comes to explaining the central role of measurement in the process sector, sensor specialist and managing director of PLUS Automation Mark Weymouth suggests the management performance guru H. James Harrington’s definition.
“I am a great believer in Harrington’s observation that measurement is the first step that leads to control and eventually to improvement. If you can’t measure something, you can’t understand it,” says Weymouth.
Thus, he adds, sensors which provide precise and reliable measurement can drive process efficiency improvements.
Inventiveness is not in short supply and has been encouraged further by the twin effects of Brexit and the pandemic. Both have added to the demand for faster production delivery and processes aligned to quality assurance.
The trick as ever is to offer products that exert a clear impact on business objectives, so that adoption is not seen merely as desirable but necessary. And as business’ priorities have changed or expanded, so have the opportunities for measurement and its associated tasks.
Within the oil and gas sector, the need to adapt to new environmental expectations for cleaner fuel has provided one catalyst.
Gas suppliers keen to reduce carbon emissions, for example, have explored mixing low levels of hydrogen with natural gas. This in turn has driven demand for meters that can cope with potentially hazardous combinations.
One necessary step is to test the performance of the meters themselves under the most demanding conditions – a challenge Chell Instruments is seeking to address with its new GMTS2000 Environmental Chamber, enabling meters to be tested using hazardous gases.
This enables safe testing using flammable and explosive gases which accurately reflect the gases which meters are intended to carry, explains sales director Jamie Shanahan.
“With gas companies looking at new ways to ‘dose’ gas supplies with other gases, we wanted to develop a safe and adaptive environment in which they can test products now and in the future.
“Manufacturers want to test their products in as close to real world conditions as possible as well as on worst-case scenarios.
With the GMTS, they can safely use hazardous gases whilst running the range of flow rates and temperature variables they need.”
Safe and sound
Whilst most testing and calibration apparatus utilises air and other low-risk gases, he says, the new system incorporates risk-assessed features which make it safe for more volatile and combustible gases.
The chamber enables devices to be tested with air, nitrogen, hydrogen or methane. Temperatures ranging from -30 to +70°C; flow rates from 20 sccm (0.0012 m3/hr) to 480 slpm (28.8 m3/hr).
Environmental concerns have also seen greater interest in boosting the effectiveness of measuring instrumentation for water pollution.
Watson-Marlow Fluid Technology Group has been drafted by the Bundeswehr University in Munich’s state-funded PLASTRAT project, addressing the problem of microplastic pollution in inland waters – an issue previously overshadowed by the focus on ocean waters.
A key interest was the development of a uniform method for extracting samples, in order to permit proper comparison and measurement, excluding contamination by other types of plastic particles.
The solution is a Watson-Marlow 300 series cased tube pump with a closed peristaltic pumping system, ensuring only the tube comes into contact with the medium.
Self-priming prevents damage caused by running dry during continuous autonomous sampling and powerful suction handles any height difference between sample and holding tank.
The greatest direct influence on level measurement has undoubtedly been the extension of automation and digitalisation.
However, says PLUS Automation’s Weymouth: “Sensors have always been key in providing reliable triggers and verifications to PLCs in automated systems aka Industry 3.0 systems.
“The past decade has seen technical developments such as the IO-Link communication protocol (IEC 61131-9) offer additional features like remote set-up and automated configuration which also help implement Industry 4.0 solutions.”
More recently, he adds, smart sensors are entering the market, enabling, for example, Contrinex to offer analogue inductive sensors “which can measure positions at micron accuracy and also now provide 16-bit digital data for distance measurement, plus additional information such as a count and temperature values as well as multiple configurable alarms”.
While adoption of new technology to improve measurement has not been slow and boosted by increased affordability, it has been variable, reckons Weymouth.
“Automation is well-embedded within the process industry and, in my experience, often the biggest challenge to implementing Industry 4.0 is how well a business understands its process and its challenges.”
I am a great believer in Harrington’s observation that measurement is the first step that leads to control and eventually to improvement. If you can’t measure something, you can’t understand it
Mark Weymouth, sensor specialist & MD, PLUS Automation
His own experience with take up of Contrinex sensors in the UK suggests that some firms have been quick to appreciate the benefits of robustness, precision and reliability but slower to make use of preventative maintenance functionalities.
“Preventative maintenance functionality in most of their sensors is less well-known about and so tends to be utilised less in the UK, which at times feels like a missed opportunity,” he notes.
It’s a point not lost on market leaders such as Endress+Hauser. The company’s comprehensive range of measurement tools for a wide variety of applications across all process sectors is complemented by a heavy emphasis on the value of instrument diagnosis and its contribution to operational cost savings.
Indeed, the company defines plant asset management as “one of the most important trends in process history”, with value enhanced by the extension of digital communication capacity. Its instruments support the NAMUR NE107 diagnostic categories – failure/ function control/maintenance requirement/non-conformance to specification – classifying problems and ensuring the appropriate persons receive immediate warning.
But while integrated asset management systems can bypass the shortcomings of human operators, access to supplier expertise and guidance remains an issue for equipment users.
Covid-related travel restrictions have underlined the necessity for other approaches to supplement face to face training, adds Chell Instruments’ Shanahan, following the recent purchase of the company’s environmental testing chambers by a major Asian client. Yet again technological enhancements have come to the rescue as “not being able to jump on a train or plane to support our clients is something we’ve all had to adapt to”, he says.