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Valve Flow Equation:
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The valve flow equation converts pressure in inches of water to flow rate for a valve using the valve coefficient (Cv). This calculation is essential for hydraulic system design, valve sizing, and flow control applications.
The calculator uses the valve flow equation:
Where:
Explanation: The equation shows that flow rate is proportional to the square root of the pressure drop across the valve, scaled by the valve's flow capacity coefficient.
Details: Accurate flow rate calculation is crucial for proper valve selection, system design, ensuring adequate flow for processes, and preventing issues like cavitation or insufficient flow.
Tips: Enter the valve coefficient (Cv) and pressure in inches of water. Both values must be positive numbers. The Cv value is typically provided by valve manufacturers.
Q1: What is the valve coefficient (Cv)?
A: Cv is a dimensionless number that represents the flow capacity of a valve. It's defined as the flow of water in GPM at 60°F that will produce a 1 psi pressure drop across the valve.
Q2: Why is the pressure in inches of water?
A: Inches of water is a common unit for low-pressure measurements in HVAC, plumbing, and hydraulic systems. 1 psi = 27.68 inches of water.
Q3: Can this equation be used for other fluids?
A: This specific equation is for water. For other fluids, additional factors like specific gravity and viscosity must be considered.
Q4: What are typical Cv values?
A: Cv values range from less than 1 for small valves to over 1000 for large industrial valves, depending on valve size and type.
Q5: When is this calculation most useful?
A: This calculation is essential for system designers, engineers, and technicians working with fluid control systems, irrigation, HVAC, and industrial processes.