01_Series07

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Velocity LimitationsIn selecting a valve for either a liquid or gas / vapor application one ofthe major considerations is the effect of fluid velocity. high velocitycould lead to operational problems ....

Velocity LimitationsIn selecting a valve for either a liquid or gas / vapor application one ofthe major considerations is the effect of fluid velocity. high velocitycould lead to operational problems including erosion, excessive vibrationand instability. The following tables indicate the maximum recommendedvelocity values for liquid and gas / vapor services.Table 5. Recommended maximum velocities for liquid service .Valve SizeMaximum VelocityCarbon SteelAlloy SteelBronze, Cu / Ni AlloysinMmft/sm/sft/sm/sft/sm/s0.5 - 215 ? 504112.54614257.63 - 680 ? 1503410.43410.4206.28 -12200 ? 300298.9298.9175.2Table 6. Recommended maximum velocities for Gas/ Vapor servicesValve SizeMaximum lnletVelocityMaximum OutletVelocityMax. Outlet MachNumber forRequired Noise Levelin Mm ft/s m/s ft/s m/s >95 dBA <95 dBA <85 dBA0.5 - 2 15 ? 50 340 1043 - 6 80 ? 150 294 90830 253 0.65 0.5 0.38 - 12 200 ? 300 265 81Inherent RangeabilityThe inherent rangeability of a control valve is the ratio betweenmaximum and minimum flow with in the working characteristic atconstant pressure drop.Table 7. Rangeability valuesTrim Size(ins) /Trim NumberMaximum RangeabilityTrim N0. 1 ? 5Trim size 1/16”? 3/4”Trim size 1”- 16”10 : 130 : 150 : 1?50 : 1100 : 1? special6