Float-area-type Flow Meters with Constant Discharge Coefficients : General Flow Rate Characteristics When the Gradient of a Tapered Tube is Large

Abstract

Discharge coefficients, including general flow rate characteristics when the gradient of a tapered tube is large, of float-area-type flow meters are generally discussed. It is experimentally pointed out that the discharge coefficients became constant when a float, having the small length of the maximum diameter part of the float and having 180° vertex angle of the cone portions upstream of the maximum diameter part of the float, and a particular tapered tube having the gradient k=0.545 are employed. When employing such a combination of the float and the tapered tube, a semi-empirical formula to predict the flow rate characteristics is obtained and the limits of applicability of the formula are experimentally explained. Finally, a float-are-type flow meter having linear relations between the flow rate and the position of the float is manufactured.