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Hi all, I want to place a Mag Flow and Keystone-Valves Butterfly control valve into a 200mm line. (Process fluid is Dilution - weak Liquor-NaCO-Caustic, 70 GPL of solids, slightly scaling) The Cv calculated ( 694 ) for the valve indicates I need a 100mm (CV = 681) valve for Maximum flow. (Flow 405 m3/hr, Inlet Pressure 133 kpa, dp 50, temp 90 Deg C, Sg 1.1, Viscosity 1.2 kPa.S) A 100mm Mag Flow will have a 14 m/s Max flow velocity, 200mm Mag flow Max flow velocity would be 3.58, 150mm mag flow will have a more reasonable Max flow velocity of 6.37 m/s. Should I 1. over-size the control valve and make the mag flow and control valve 150mm (Cv = 2310) to reduce the flow velocities? 2. Or use a 100mm Magflow and except the 14m/s flow velocity (This will look strange 200mm line to 100mmline back to 200mm) 3. Or have 3 different pipe sizes (200mm To 150mm To 100mm back to 200mm) I am not sure which is the lesser of the three evils. Option 2 and 3 will be an unpopular choice with maintenance and production for different reasons, and I don't think option 1 will control effectively. Have I picked the wrong type of valve ? (Butterfly Valves historically have been used for this process at this refinery, and I thought it was a good choice) This is not a big issue, but I am interested in your opinions. regards, Richard King Alesa Alusuisse Engineering Australia Pty Limited. Phone: +61 7 3218 3555 Fax : +61 7 3236 0155 Email: [email protected] Web : http://www.alesa.com.au