Results of the V-cone flow meter tests conducted in accordance with new API protocol

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he American Petroleum Institute Manual of Petroleum Measurement Standards, Chapter 5.7 (API 5.7) specifies a testing protocol for differential pressure flow measurement devices. The protocol was written to apply to all flow measurement devices that measure single-phase fluid flow based on the detection of a differential pressure created in the fluid flow stream. This standard was published in January 2003 “to supply industry with a comparable description of the capabilities of these devices for the measurement of single-phase fluid flow when they are used under similar operating conditions.”

This White Paper will show how API 5.7 was applied to the McCrometer V-cone flow meter in gas and liquid testing. The results indicated that the V-cone flow meter could be used with similar accuracy in both gas and liquid applications. Furthermore, in the non-standard gas tests, the V-cone flow meter demonstrated a difference in the measured discharge coefficient of less than ± 0.50% compared to the baseline test.

Through the use of the test protocol, the authors have identified areas of the standard that may require more detail or possible revision. One of the issues of concern is the adequacy of the testing required for the non-standard installations. At present, API 5.7 requires testing of the differential pressure device in non-standard installations using one beta ratio, but tests at additional beta ratios and pipe diameters may be desirable to assess the performance of some meters. For the half moon orifice test, the orientation of the plate relative to any asymmetry within the meter is not defined. Additional issues that are addressed in the paper include the method required to decide the acceptability of the test laboratory and the specific requirements of the swirl generator test. These issues and possible solutions are addressed in the paper.