Modern water flowmeters: Differential pressure flowmeters

Abstract

Beeing a part of the no moving parts instruments, differential flow meter are mainly used in the industrial environment, not being found in house hold use. The basic functional principle consists in the appearance of a differential pressure between two points of the flow, if between this comes a flow resistivity object (obstacle, strangulation, elbow). The relationship between pressure and velocity is described by the Bernoulli equation. Measuring the pressure difference the velocity can be calculated and the flow implicitly. There are a several kinds of differential pressure flow meters: Venturi, Nozzle, Pitot, and measuring diaphragms. This paper refers to an experimental method for determining the constant K, for the constant flow cross-section of the flow meters and the pressure drop variable.