How do you calculate control valve size?
The volume flow rate for liquids can be calculated by multiplying the fluid velocity times the flow area. Thus, Cv is numerically equal to the number of U.S. gallons of water at 60°F that will flow through the valve in one minute when the pressure differential across the valve is one pound per square inch.
How are Cv control valves calculated?
Because the fluid is a gas and ΔP ≥ P1 / 2 so we will use the formula. Cv = (48000 / (248 × 33.03)) x sqrt (0.86 x (273 240)).
What is ISA S 75.01 standard?
ISA-75.01. 01-2007 includes equations for predicting the flow coefficient of compressible and incompressible fluids through control valves. The equations for incompressible flow are based on standard hydrodynamic equations for Newtonian incompressible fluids.
How do you size a valve?
The basic valve sizing equation Q = Cv√∆P can be used to calculate pressure drop, flow rate, or the flow coefficient. For solutions other than water, a correction for a difference in specific gravity of the solution is necessary. This revised formula would be: Q = Cv[√∆P/Sg] with Sg = specific gravity of the liquid.
What is xT in control valve sizing?
For compressible fluids, a terminal pressure drop ratio, xT, similarly describes the choked pressure drop for a specific valve. When sizing a control valve, the smaller of the actual pressure drop or the choked pressure drop is always used to determine the correct Cv.
How do you convert KV to Cv?
The Relationship between Cv and Kv is Cv = 1.156 Kv OR Kv = 0.864 Cv. 1 psi = 0.06894757 bar.
How do you calculate Cv flow?
A practical example, if we wanted to calculate Cv to select a valve for 10 GPM flow with a required ΔP of 4, first find the square root of the ΔP √ 4=2, and use that to divide the flow of 10 GPM 10/2 = 5, which results in a Cv requirement of 5.
What is piping geometry factor?
Piping geometry factor, abbreviated as Fp, a dimensionless number, is the pressure and velocity changes caused by fittings such as bends, expanders, reducers, tees, and Y’s if directly conected to the valve.
How do I choose a control valve?
When choosing a control valve for a process, there are many things that must be considered, including the valve’s flow characteristic, its size, noise, the potential for cavitation or flashing damage, body and trim materials, actuator size and type, and its dynamic response to changes in the control signal.
What is FL and xT in control valve?
ANSI/ISA liquid sizing Equations use a pressure recovery factor, FL, to calcu- late the ∆Pch at which choked flow is assumed for sizing purposes. For compressible fluids, a terminal pressure drop ratio, xT, similarly describes the choked pressure drop for a specific valve.
What is Cv value of control valve?
Valve Flow Coefficient (Cv) is the flow capability of a control valve at fully open conditions relative to the pressure drop across the valve. It is defined as the volume of water (GPM in the US) at 60°F that will flow through a fully open valve with a pressure differential of 1 psi across the valve.
What is the Masoneilan control valve sizing Handbook?
Masoneilan Control Valve Sizing Handbook | 3 Foreword This handbook on control valve sizing is based on the use of nomenclature and sizing equations from ANSI/ISA Standard S75.01.01 and IEC Standard 60534-2-1. Additional explanations and supportive information are provided beyond the content of the standards.
What is the velocity of steam flow in Masoneilan control valve?
Masoneilan Control Valve Sizing Handbook | 23 Figure 4 Saturated Steam Flow vs Pressure for 1” to 12” Schedule 40 Pipe Velocity — 130 to 170 feet per second — — 50 to 60 meters per second — U.S. Customary Units Metric Units 24 | Baker Hughes 2022 Baker Hughes. All rights reserved. Commercial Wrought Steel Pipe Data (ANSI B36.10)
What are Masoneilan’s sizing equations?
Masoneilan sizing equations have been used for nearly fifty years to determine the capacity requirement of control valves. The most recent version of Masoneilan’s sizing equations for liquid and gas/vapor service are presented here as a reference for those w ho wish to refer to, or continue to use these equations.
What is the CV of Masoneilan liquid flow?
Masoneilan Liquid Flow Equations Cv= valve flow coefficient N=numerical constants based on units used (see Table 1) Fp= piping geometry factor (reducer correction) FF= liquid critical pressure factor = 0.96 – 0.28 pv pc