STUDY OF THERMAL EFFECT ON CALIBRATION OF AN ULTRASONIC FLOW METER

Ching-Yi Kuo, Jiunn-Haur Shaw, Chun-Min Su

Abstract

A primary high pressure air flow measurement standard was constructed at Center for Measurement Standards (CMS) in Taiwan with a capacity of 18000 m3/h and pressure range of 1 to 60 bar. With present calibration setup, the temperature of air flowing through the meter under test (MUT) decreased significantly during a test. To reduce thermal effect during meter calibration, improvements have been made by expanding the upstream air storage tank from 19 m³ to 34 m³, and installing a new compact sonic nozzle array (CSNA) downstream of the MUT as a new working standard (WS). A re-circulating loop at CMS was retrofitted and completed at the end of 2012. The calibration results of an ultrasonic flow meter (USM) between two different facilities and two different CSNA were compared. Results showed that after expanding the capacity of the upstream air storage tank, the change rate of air temperature during calibration could be reduced. With such decreasing rate, the time-delay problem of temperature measurement at the meter has been alleviated. The calibration of a DN 150 SICK USM showed good comparison between the two different facilities and the two different CSNA as working standard.

Keywords

primary standard, high-pressure, air speed, sonic nozzle, ultrasonic

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DOI

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IMEKO TC

TC9 - Flow Measurement

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