Application Guidelines for the Multiple-Orifice Flowmeter: A Wide-Range, Economical, Fluid-Flow Measurement Concept

摘要

The need to measure gas flow over a wide range of flow rates accurately and economically occurs in a variety of commercial and research situations. One such application is that of the State-of-the-Art and Prototype Lockhopper Valve-Testing and Development Projects at the Morgantown Energy Technology Center (METC) of the US Department of Energy. These projects evaluate valves being developed for use in coal-conversion pilot plants by subjecting them to a variety of simulated process conditions and measuring their leakage rates. Initial leakage tests indicated that a wide range of leakage rates could occur, ranging from 0.06 standard cubic feet per minute (scfm) to as high as 80 scfm at pressures ranging from 100 to 1600 psig. This required a flow-rate measuring technique with a wide-range capability and an accuracy approaching 1 percent of full scale. To meet this requirement, METC developed a unique flow-measurement concept that utilizes a multiple-orifice system with a single differential pressure transmitter. This report describes the devlopment of this concept, design procedure, and application, as well as the calibration and operation of the device. This report shows that the multiple orifice flowmeter can perform comparably to conventional single-orifice flowmeters in terms of accuracy while allowing several orders of magnitude improvement in flow range. (ERA citation 07:047926)