Sixteen years ago, I became an editor, and a blogger, in modern parlance. It was the right move for me, aged 54 then, but I left behind 24 years of trying to get to a dream, an un-achieved objective. I was a process instrumentation marketing engineer, and the objective was to create the ultimate clamp-on non-
intrusive ultrasonic flowmeter. I did not have to do the hard research and build work, I just had to find the right guys who could do that, and pull a team together to make it happen.
It seemed basically no big deal. Medical professionals had been doing it for years. Blood flow round the body could normally be monitored through the skin, even at a distance from the vessel wall. But blood is easy: it is a slurry so a Doppler system worked perfectly. It was 1977 when I pulled a boffin inventor in Norfolk and a subcontract manufacturer in Southport together with marketing from Bestobell Mobrey to launch their Doppler flowmeter, a clamp-on single transducer device. It was not the first available, but it took the market by storm. As ever, performance was brilliant on the perfect application, a liquid with bubbles or solids to give good reflections. As a profitable product, it was a major success, and satisfied the majority of customers. Later, it was over sold, misapplied onto clean liquids, and gained a poor reputation.
The next logical step was to ‘Time-of-Flight’ flowmeters. Bestobell continued this vein in the 1980s with the Sparling unit, very successful in water industry applications, but using a pipe spool-piece. Then there were hot-tapped designs, drilled into existing mains. An alternative option was a U-shaped flow tube, with the ultrasound travelling across the bottom of the ‘U’. This was developed by a contract research company into a domestic gas meter, and the UK gas meter manufacturing operation was later sold off to Siemens. But some newly established manufacturers, I think using university based ultrasonic transducer technology – which is the clever bit here – produced clamp-on designs for existing pipework, for liquid flow monitoring, and really did a magnificent job.
Clamp-on developments
It was interesting that these developments came from outside the established process instrumentation supplier base, arising out of university technology research. The only established firm which came close, probably based on US naval research contracts, was Panametrics, but when GE bought it that sparkle disappeared. The others that I can remember now were Flexim and Katronics, both from Germany.
In the 1980s, in a chapter of a book reviewing the ultrasonic instrumentation available for use in the food industry, I said there would never be an ultrasonic clamp-on gas flow measurement system suitable for metal pipework. But 10 years later Flexim had achieved this – for gas and steam flow measurement!
It was in the 1990s, when working with Platon Instrumentation, that we decided to develop a clamp-on time-of-flight flowmeter using a ‘V’-shaped path, once the pipe size and wall thickness were defined. Optimised, the system worked well, but the difficulty came with the pipe definition and materials – and the product, the ‘Kat’, failed. It is possible similar efforts at the other major instrumentation companies also failed, although maybe not so publicly.
The current status
Now, at the end of 2016, Flexim and Katronics are still in business and Krohne has a full clamp-on flowmeter capability. The news this year that Emerson has negotiated a partnership with Flexim, to sell the Flexim range of clamp-on ultrasonic flowmeters is perhaps the proof that this technology is not that simple to master, as Emerson has its own well-established range of Daniel ultrasonic pipe-section flowmeters for gases and liquids.
Maybe this situation gives an opportunity for other fledgling technology-based flowmeter specialists, such as Exeter University spin-off Flotec (UK), which currently supplies its clamp-on systems into water/food disinfection processes and water distribution monitoring systems. Another unique development is the Process Atrato very low flow ultrasonic flowmeter from Titan Enterprises. Using research and technology from Cranfield University, the flowmeter can operate on small pipe sizes with liquid flows from 2 mL/min to 20 L/min, using an easily inserted flowtube.
Nick Denbow spent 30 years as a UK-based process instrumentation marketing manager, and then changed sides – becoming a freelance editor and starting Processingtalk.com. Avoiding retirement, he published the INSIDER automation newsletter for five years, and then acted as their European correspondent. He is now a freelance Automation and Control reporter and newsletter publisher, with a blog on www.nickdenbow.com
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