1. What is a Cv to Flow Rate Calculator?

Definition: This calculator estimates the flow rate through a valve based on the valve coefficient (C_v), pressure drop, and fluid specific gravity.

Purpose: It helps engineers and technicians determine the flow capacity of valves in fluid systems.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Q \) — Flow rate (gallons per minute, GPM)
• \( C_v \) — Valve coefficient (dimensionless)
• \( \Delta P \) — Pressure drop across valve (psi)
• \( SG \) — Specific gravity of fluid (dimensionless, 1 for water)

Explanation: The flow rate is proportional to the valve coefficient and the square root of the pressure drop to specific gravity ratio.

3. Importance of Flow Rate Calculation

Details: Proper flow rate estimation ensures correct valve sizing, system performance, and prevents issues like cavitation or excessive pressure drop.

4. Using the Calculator

Tips: Enter the valve C_v value, pressure drop in psi, and specific gravity (default 1 for water). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is valve C_v?
A: The valve coefficient is the number of US gallons per minute of water that will flow through the valve with a 1 psi pressure drop.

Q2: What's a typical C_v value?
A: C_v values vary widely by valve type and size, from <1 for small valves to >1000 for large industrial valves.

Q3: When would I change the specific gravity?
A: When working with fluids other than water. For example, SG ≈ 0.8 for gasoline, ≈1.03 for seawater.

Q4: How do I find the C_v for my valve?
A: Check manufacturer specifications or valve nameplate. C_v is typically provided in technical datasheets.

Q5: Does this work for gases?
A: This formula is primarily for liquids. Gas flow calculations require additional factors like temperature and compressibility.