Influence of Effective Head on the Characteristics of Flat-Seated Disc Valve : 9th Report, Experimental Research on Disc Valves

Abstract

The experiments were performed on three flat-seated disc valves, having diameters d of 28.0, 30.2 and 38.8 mm, discharging water into the air under a constant head H which was varied from 194 cm to 9 cm. The discharge Q and the lifting force P were precisely measured at each valve lift l. The results show that ; (1) discharge coefficient ∝Q/l√(H) is more markedly affected than the non-dimensional lifting force ∝ P/H by the effective head H ; (2) if the lift l is not so small, the influence of H on Q/l√(H) and P/H becomes very small when H is greater than 194 cm ; (3) four special points are marked on a characteristic curve for H greater than 49 cm. Besides this many unexpected relations are observed.