Problems with the Aniuoba flow meter
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The company has chosen Emerson’s Avena flowmeter to measure the flow rate at the outlet of the blower. It is installed after the preheater and features temperature compensation; three Anuba units are connected in parallel within one air duct section. The air duct is large, measuring 360CM*170CM, and the front and rear dimensions do not meet the 7D and 5D requirements. The problem now is that the actual air volume (estimated based on natural gas matching) is 30,000 cubic feet less than what the DCS shows; the error is too large, which causes frequent alarms in the process, and sometimes it approaches the interlock value. Interlock for 2003: on-site calibration of the three gauges – they all showed the same reading, and purging had no effect. Please ask Haiyou for guidance!
What a large cross-sectional area! With three connected in parallel, on the same plane – is there still any axial deviation? If there are no straight sections before and after, it’s not possible to ensure a consistent pressure difference; without proper measurement, the pressure difference cannot be determined accurately. Do your measurement values fluctuate frequently?
It is a square air duct with dimensions of 360CM*170CM; in one cross-section, there are three sections at the top, middle, and bottom, with virtually no deviation between them. It is connected in parallel, with three transmitters used. The reason for this is that due to on-site conditions and past issues, there isn’t enough straight section ahead and behind. If the measured values fluctuate frequently, the DCS display shows too low a value, resulting in large errors; for example, an actual air flow of 150,000 is shown as 120,000 by the DCS. The goal is to reduce these errors. . . Some people say that Aniu Ba is most suitable for circular air ducts. Is that true?
The last edit to this post was made by HEJIYUER on 2015-6-30 at 12:26. In a given cross-section, the velocity distribution fields at the upper, middle, and lower measurement points are different; ANNUBA “infers” the average flow velocity (which equals the flow rate) for the entire pipe based on the velocity distribution at the center of the pipe. The other party is in charge of the measurement; it involves a special configuration. Please have the original poster contact EMERSON to recheck the calibration data. Are the readings of the three instruments close to each other? Which one is always too big?
I’m also looking at it; I’m also concerned about this issue
The pressure tapping tubes of the 3 flowmeters are connected to each other and in communication; the 3 gauges are also basically the same, with little difference between them. EMERSON makes corrections based on the internal cross-sectional area of the square pipe, and the result of these corrections is a change in DP of 0.001 units, which is completely meaningless. For measuring air flow in large square ducts of dimensions like 360CM*170CM, what type of meter is suitable? The orifice plate won’t work, and the venturi is too large? ?
15 is the actual value; so what is the total of those three flow meters? Your description isn’t very clear