1. What is Flow Rate from CV Calculator?

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

Purpose: It helps engineers and technicians determine the flow capacity of valves under specific operating conditions.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

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

Explanation: The flow rate is directly 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 process control in fluid systems.

4. Using the Calculator

Tips: Enter the valve C_v (from manufacturer specs), pressure drop across the valve, and fluid specific gravity (default 1.0 for water). All values must be > 0.

5. Frequently Asked Questions (FAQ)

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

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

Q3: Can I use this for gases?
A: This formula is primarily for liquids. Gas flow calculations require additional factors like temperature and compressibility.

Q4: How do I find the C_v for my valve?
A: C_v is typically provided in the valve manufacturer's specifications or technical datasheet.

Q5: What if my fluid is not water?
A: Use the specific gravity of your fluid relative to water (SG of water = 1.0). For example, SAE 30 oil has SG ≈ 0.89.