Characteristics of Flat-Seated Disc Valves for Discharging Water into Water : Experimental Research on Disc Valves, 10th Report

Abstract

Experiments of discharging water into water were performed using two disc valves i'and h', with broader valve seat face in comparison with earlier experiments of discharging water into air. The characteristic curves of valve i'change continuously unlike those of the valve for discharging water into air. The same curves of valve h'change a little discontinuously at a larger lift than one for discharging water into air. Excepting the vicinity of discontinous change, the discharge coefficients of valve i'and h'do not differ between discharging water into water and discharging water into air but the nondimensional lifting force in the case of discharging water into air is larger than that in the case of discharging water into water. These phenomena were illustrated by the measurement of pressure head at the center of the valve seat and the observation of the movement of fine silk threads attached to the periphery of the valve and the valve seat, and so on. By these experiments, the difference of the valve characteristics between discharging water into air and water into water was made clear.