The performance of transit time ultrasonic flowmeters under good and disturbed flow conditions

Abstract

A series of tests was carried out to assess the performance of transit time ultrasonic flowmeters in both good and disturbed flow conditions. In Phase I, eleven commercial meters were tested in good flow conditions. These meters included single-beam wetted and clamp-on designs and a dual-beam wetted design. Only two performed within the manufacturers' specification. In Phase II, the performance of the different designs was investigated when positioned downstream of various pipe fittings, i.e. gate valve (25% and 50% closed), one bend, two bends (perpendicular planes) and a reducer. All the results are summarized. The single-beam meters showed shifts of up to 11% at a 10 D spacing: the dual-beam meter was significantly better, i.e. 1.5% at 10 D.