1. What is GPM to SCFM Conversion?

The GPM to SCFM conversion calculates the Standard Cubic Feet per Minute (SCFM) of gas flow from Gallons per Minute (GPM) of liquid flow, accounting for pressure, temperature, and specific gravity differences.

2. How Does the Calculator Work?

The calculator uses the SCFM formula:

Where:

• \( GPM \) — Gallons per minute (gal/min)
• \( P \) — Absolute pressure (psia)
• \( T \) — Absolute temperature (Rankine)
• \( SG \) — Specific gravity (unitless)
• 14.7 — Standard atmospheric pressure (psia)
• 530 — Standard temperature (Rankine)

Explanation: The formula converts liquid flow rate to equivalent gas flow rate at standard conditions, accounting for differences in pressure, temperature, and gas density.

3. Importance of SCFM Calculation

Details: Accurate SCFM calculation is crucial for sizing pneumatic equipment, designing compressed air systems, and ensuring proper operation of gas-handling equipment.

4. Using the Calculator

Tips: Enter GPM in gallons per minute, pressure in psia, temperature in Rankine, and specific gravity. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between GPM and SCFM?
A: GPM measures liquid flow rate while SCFM measures gas flow rate at standard conditions (14.7 psia and 60°F/520R).

Q2: Why use absolute pressure (psia) instead of gauge pressure (psig)?
A: Absolute pressure includes atmospheric pressure and is required for accurate gas law calculations.

Q3: How do I convert Fahrenheit to Rankine?
A: Rankine = Fahrenheit + 459.67. Standard temperature is 60°F = 519.67R (often rounded to 520R or 530R in different standards).

Q4: What is specific gravity and how is it determined?
A: Specific gravity is the ratio of gas density to air density at standard conditions. Air has SG = 1.0.

Q5: When is this conversion typically used?
A: This conversion is commonly used in pneumatic system design, compressor sizing, and when comparing liquid and gas flow rates in mixed systems.