1. What is a Pressure Drop Calculator?

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

Purpose: It helps engineers and technicians determine the pressure loss when fluid flows through a valve, which is crucial for system design and analysis.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

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

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

3. Importance of Pressure Drop Calculation

Details: Proper pressure drop estimation ensures correct valve sizing, maintains system efficiency, and prevents cavitation or flow restriction issues.

4. Using the Calculator

Tips: Enter the flow rate in gpm, valve C_v value, 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 valve coefficient is a measure of a valve's flow capacity - the flow rate in gpm that produces a 1 psi pressure drop.

Q2: What's a typical C_v value?
A: C_v varies by valve type and size - from single digits for small valves to thousands for large valves.

Q3: When would I change the specific gravity?
A: For fluids other than water - SG is the ratio of the fluid's density to water's density at 60°F.

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

Q5: What if I get negative results?
A: All inputs must be positive numbers. Negative results indicate invalid input values.