Flowmeter: Thermal mass device includes self calibrating capability
While thermal mass flowmeters have many useful capabilities, (see tutorial above) calibrating them in-plant is challenging. Like many other types of instruments, they normally have to be taken out of service and sent to the manufacturer or a lab for precise calibration. FCI now offers an in-situ calibration feature for its GF90 air/gas flowmeter that allows calibration in the plant, and often without removing the unit at all.
The VeriCal in-situ calibration verification system for the GF90 flowmeter is reportedly an easy, fast, and low cost way to confirm gas flow calibration accuracy to meet process validation, safety and environmental regulation requirements.
The VeriCal system is a specially manufactured and plumbed GF90 flow element with additional electronics to feed and measure a precise flow of gas from a nitrogen source. To test a unit, nitrogen gas is flowed through the meter’s flow element and measured at five pre-set measurement points across the meter’s range. The in-situ flow meter test data is then compared to original laboratory calibration and installation benchmark test data for that specific meter.
The GF90 flowmeter with the calibrating feature is ideal in a wide range of applications for oil/gas production, refining, chemical plants, electric power generation, and anywhere periodic flow meter calibration validation is required by the process or regulations.
FCI says the GF90 flowmeter delivers high accuracy measurement over a wide range, including low flows. It is designed with a thermal mass gas flow sensing element of 316 stainless steel and nickel-braze construction. With constant power technology, the GF90 can achieve turndowns from 1000:1, accuracy of
—Edited by Peter Welander, process industries editor, PWelander@cfemedia.com ,
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