Ultrasonic Flow Meter Diagnostics and the Impact of Fouling |
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| Jan G. Drenthen, Marcel Vermeulen, Martin Kurth, Hilko den Hollander |
- Abstract:
- Over the past decade, Ultrasonic flow meters have gained a wide acceptance. Main reasons for this are the high repeatability in combination with zero pressure loss and extensive diagnostic features. During this period meters with different path configurations have been put into the market, each of them trying to obtain the highest accuracy. Many of them show (often after multipoint linearization) almost perfect straight lines with errors close to the repeatability of the lab.
However, for a user it is not only important how good his meter is at the lab, far more important is the accuracy after installation in the field and the question how the user can be sure that the meter’s performance is not deteriorating over time.
Major factors affecting the performance of a meter installed in the field are corrosion and fouling. This is not only a problem for ultrasonic meters, but it will affect every flow meter installed. The great virtue of ultrasonic flow meters in contrast to all other meters, are their huge diagnostic capabilities. In addition to this, ultrasonic flowmeters that use reflecting paths are also capable in detecting changes of the conditions at the pipe wall. As a result these meters have huge advantages over straight path meter designs which are not capable of detecting anything occurring at the pipe wall.
While there are multiple papers on the performance in calibration laboratories, the impact that fouling and corrosion can have on the performance of an ultrasonic meter is less known. One of the first papers describing the impact of installation conditions was that of Rick Wilsack from TCPL [2]. Recently James Witte has presented a paper including also the impact that it has on the flow velocity profile [5]. Acknowledging the impact that installation conditions and fouling can have on the performance of a meter, was the basis for KROHNE to design their ALTOSONIC V12 ultrasonic flowmeter.
The present paper focuses on the impact of fouling and corrosion and addresses:
• the design considerations
• the ways to detect the various categories of fouling
• the tests performed with dirty meters
• the impact of honed versus corroded upstream pipes
• the impact of corrosion of the reflecting surface.
Next to this, a first order correction is given, based on information gathered from the reflecting paths. - Download:
- IMEKO-TC9-2010-032.pdf
- DOI:
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