1. What is Flow from Differential Pressure?

Definition: This calculator determines the flow rate through a valve or orifice based on the valve coefficient, pressure drop, and fluid specific gravity.

Purpose: It helps engineers and technicians size valves and predict flow rates in fluid systems.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Q \) — Flow rate (gallons per minute)
• \( C_v \) — Valve flow coefficient (dimensionless)
• \( \Delta P \) — Differential pressure (psi)
• \( SG \) — Specific gravity of fluid (dimensionless)

Explanation: The flow rate is proportional to the square root of the pressure drop divided by the specific gravity, scaled by the valve coefficient.

3. Importance of Flow Calculation

Details: Accurate flow calculations ensure proper system design, valve sizing, and process control in fluid systems.

4. Using the Calculator

Tips: Enter the valve coefficient (C_v), pressure drop in psi, and fluid specific gravity (default 1.0 for water). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is the valve coefficient (C_v)?
A: C_v is a measure of a valve's flow capacity - the flow in gpm of water at 60°F that will pass with a 1 psi pressure drop.

Q2: What's a typical C_v value?
A: C_v varies by valve size and type - from <1 for small valves to >1000 for large control valves.

Q3: When would I change the specific gravity?
A: Use 1.0 for water. For other fluids, use their SG relative to water (e.g., 0.79 for gasoline, 1.03 for seawater).

Q4: Does this work for gases?
A: No, this formula is for liquids. Gas flow calculations require different formulas accounting for compressibility.

Q5: What if my pressure drop is too high?
A: High ΔP may cause cavitation. Consult valve manufacturer's specifications for maximum recommended ΔP.