1. What is a Flow Rate to Pressure Calculator?

Definition: This calculator determines the pressure drop (ΔP) across a valve or restriction based on flow rate, flow coefficient (C_v), and fluid specific gravity.

Purpose: It helps engineers and technicians in fluid systems design to understand pressure losses in piping systems.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( \Delta P \) — Pressure drop (psi)
• \( Flow \) — Flow rate (gallons per minute, gpm)
• \( C_v \) — Flow coefficient (dimensionless)
• \( SG \) — Specific gravity of fluid (relative to water)

Explanation: The pressure drop increases with the square of the flow rate and is proportional to the fluid's specific gravity.

3. Importance of Pressure Drop Calculation

Details: Proper pressure drop estimation ensures correct valve sizing, pump selection, and system performance in hydraulic systems.

4. Using the Calculator

Tips: Enter the flow rate in gpm, the valve's C_v value, and the fluid's specific gravity (default 1.0 for water). All values must be > 0.

5. Frequently Asked Questions (FAQ)

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

Q2: What's a typical C_v value?
A: C_v varies by valve size and type - check manufacturer specifications (e.g., a 1" ball valve might have C_v = 25).

Q3: When would I change specific gravity?
A: For fluids other than water - gasoline (SG=0.72), seawater (SG=1.03), etc.

Q4: Does this work for gases?
A: This simplified formula is for liquids. Gas calculations require additional factors for compressibility.

Q5: What if my pressure drop is too high?
A: Consider a valve with higher C_v or increasing pipe diameter to reduce pressure loss.