1. What is the Flowserve Cv Equation?

The Flowserve Cv equation calculates the flow coefficient of a valve, which is a dimensionless number that relates the flow rate through a valve to the pressure drop across it. This is essential for valve sizing and selection in fluid control systems.

2. How Does the Calculator Work?

The calculator uses the Flowserve Cv equation:

Where:

• \( C_v \) — Flow coefficient (dimensionless)
• \( Q \) — Flow rate (gpm)
• \( SG \) — Specific gravity of fluid (dimensionless)
• \( \Delta P \) — Pressure drop across valve (psi)

Explanation: The equation shows that Cv increases with higher flow rates and fluid density (SG), but decreases with higher pressure drops.

3. Importance of Cv Calculation

Details: Accurate Cv calculation is crucial for proper valve selection to ensure optimal flow control, prevent cavitation, and maintain system efficiency.

4. Using the Calculator

Tips: Enter flow rate in gpm, specific gravity (1.0 for water), and pressure drop in psi. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What does Cv represent?
A: Cv represents the flow rate in gpm of water at 60°F that will pass through a valve with a 1 psi pressure drop.

Q2: How does specific gravity affect Cv?
A: Higher specific gravity fluids (denser than water) will have proportionally higher Cv values for the same flow rate and pressure drop.

Q3: When is this equation most accurate?
A: The equation works best for turbulent flow conditions and Newtonian fluids. It may need adjustment for viscous or non-Newtonian fluids.

Q4: What are typical Cv values?
A: Cv values range from less than 1 for small valves to over 1000 for large control valves, depending on size and design.

Q5: How does Cv relate to Kv?
A: Kv is the metric equivalent of Cv, where 1 Cv ≈ 1.156 Kv. The conversion accounts for different units (gpm vs. m³/h, psi vs. bar).