Page 42 - Valve Selection Handbook
P. 42
Fundamentals 29
provide only typical resistance-coefficient values. The values apply to
4
fully open valves only and for Re > 10 . Correction factor Kj for partial
valve opening may be obtained from Figures 2-4 through 2-7.
17
The Engineering Sciences Data Unit, London, deals more comprehen-
sively with pressure losses in valves. Their publication also covers correc-
4
tion factors for Re < 10 and shows the influence of valve size on the £-
Figure 2-4. Approximate Effect of Partial Opening of Globe Valves on Resistance
Coefficient. (Courtesy of Engineering Sciences Data Unit. Reproduced from Item No.
69022, Figure 13.)
Figure 2-5. Approximate Effect of Partial Opening of Gate Valves on Resistance
Coefficient. (Courtesy of Engineering Sciences Data Unit. Reproduced from Item No.
69022, Figure 14.)
