Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

LIQUID FLOW METER CALIBRATIONS WITH NIST's 15 kg/s WATER FLOW STANDARD

Published

Author(s)

Jodie Gail Pope, Aaron Johnson, James Filla, Vern E. Bean, Michael R. Moldover, Joey Boyd, Christopher J. Crowley, Iosif Isaakovich Shinder, Keith A. Gillis, John D. Wright

Abstract

We describe the 15 kg/s water flow calibration standard operated by the Fluid Metrology Group of the National Institute of Standards and Technology (NIST) to calibrate liquid flow meters for customers. The 15 kg/s standard is a dynamic, gravimetric, liquid flow standard (LFS) that determines flow by measuring the rate of change of the mass of water accumulating in a collection tank. The LFS is a fully automated system that uses two proportional–integral–derivative control loops to achieve water flows near ambient temperature with a mass flow stability that is the smaller of 0.001 % of the mass flow set point or 0.1 kg/s. The expanded uncertainty of the LFS is 0.022 % for mass flow and 0.023 % for volume flow for the flow range 0.22 kg/s to 15 kg/s. (Unless stated otherwise, all uncertainties have a 95 % confidence level.) When the LFS is used to calibrate a customer's meter, the uncertainty of the meter factor is increased by the irreproducibility of the meter under test (MUT). The most reproducible meters tested by NIST have meter-factor uncertainties of 0.035 % and 0.036 % for mass flow and volume flow, respectively. Below, we derive the equation for calculating flow at the meter under test, analyze the uncertainty of the flow standard, give supporting data, and provide a sample calibration report. This document also describes the procedures that customers must follow to submit their flow meters to NIST for calibration.
Citation
Special Publication (NIST SP) - 250-98
Report Number
250-98

Keywords

Calibration, Dynamic Gravimetric Flow Standard, Flow Meter, Uncertainty, Liquid Flow Standard

Citation

, J. , Johnson, A. , Filla, J. , , V. , , M. , Boyd, J. , , C. , , I. , , K. and , J. (2021), LIQUID FLOW METER CALIBRATIONS WITH NIST's 15 kg/s WATER FLOW STANDARD, Special Publication (NIST SP), National Institute of Standards and Technology, Gaithersburg, MD, [online], https://doi.org/10.6028/NIST.SP.250-98, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=932648 (Accessed September 21, 2021)
Created June 15, 2021, Updated July 6, 2021