Email Document Reference

Enter your email address below and the reference for this document will be sent to shortly from webmaster@ceesi.com.

Title: DIFFERENTIAL TESTING of ROTARY METERS
Author: MADELINE CORB
Source: 2019 Western Gas Measurement Short Course
Year Published: 2019
Abstract: A Differential Rate Test is an accurate and convenient method of comparing a rotary meters performance to previous or original performance records. It is widely recognized that many State Utility Commissions and other regulatory agencies accept differential testing as a means of periodically substantiating that the original accuracy of a rotary gas meter has remained unchanged. A change in internal resistance can affect the accuracy of a rotary meter. Any significant increase on the meters internal resistance to flow will increase the pressure drop between the inlet and outlet of the meter. The differential pressure appears as a prime indicator of meter condition and the test results may be used as a decision- making matrix for maintenance requirements. Resistance (increase in pressure loss) across the meter is affected by changes in flow rate, pressure, specific gravity, and internal friction. This is a good indicator to use in determining your need to pull a meter from service, or better yet a preventive maintenance program. Most meters can be flushed with an approved safety solvent, returned to service, and the differential will be close to the original data. If it exceeds specified criteria, normally a 50% increase from the baseline, the meter may require repair. The differential rate test is not an accuracy test. It does provide an excellent basis for assessing meter condition and making an educated decision as to whether the meter accuracy may be out of the users accuracy specifications.

In order to prevent spam and automated file downloads for documents within the Measurement Library, please follow the instructions below and then you will be able to email a reference to this article.