Valve Pressure Differential for Liquid Formulas |
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\( \Delta P \;=\; SG \cdot \dfrac{ Q }{ C_v }\) (English units) \( \Delta P \;=\; SG \cdot \dfrac{ Q }{ K_v }\) (Metric units) |
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| Symbol | English | Metric |
| \( \Delta P \) = valve pressure differential | \(lbf \;/\; in^2\) | \(Pa\) |
| \( C_v \) = valve flow coefficient | \( dimensionless \) | \( dimensionless \) |
| \( K_v \) = valve flow coefficient | \( dimensionless \) | \( dimensionless \) |
| \( Q \) = valve flow rate | \(ft^3 \;/\; sec\) | \(m^3 \;/\; s\) |
| \( SG \) = liquid specific gravity (water at 60°F = 1.0000) | \(dimensionless \) | \( dimensionless \) |
Valve pressure differential for liquid is the difference in pressure between the inlet side and the outlet side of a valve when a liquid flows through it. This pressure difference indicates how much energy the fluid loses while passing through the valve due to resistance, friction, and turbulence created by the valve’s internal components. In practical terms, the pressure differential determines how much flow the valve can allow, how the valve should be sized, and how efficiently it will operate in a liquid system. A higher pressure differential usually means the valve causes greater restriction, while a lower differential means the liquid passes through more easily. Understanding the valve pressure differential is essential for ensuring proper flow control, preventing cavitation, and maintaining safe and reliable operation of pumps, pipelines, and fluid-control equipment.
