1. What is Tank Level by Pressure Calculation?

Definition: This calculator determines the liquid level in a tank based on pressure measurements, accounting for atmospheric pressure and fluid properties.

Purpose: It's essential for process control, tank monitoring, and industrial applications where direct level measurement isn't possible.

2. How Does the Calculator Work?

The calculator uses the hydrostatic pressure formula:

Where:

• \( h \) — Liquid level height (meters)
• \( P \) — Measured pressure at tank bottom (Pascals)
• \( P_{atm} \) — Atmospheric pressure (Pascals)
• \( \rho \) — Fluid density (kg/m³)
• \( g \) — Gravitational acceleration (9.81 m/s²)

Explanation: The differential pressure (total minus atmospheric) divided by the product of density and gravity gives the liquid height.

3. Importance of Accurate Level Calculation

Details: Precise tank level measurement ensures proper inventory control, process safety, and prevents overfilling or dry-running of pumps.

4. Using the Calculator

Tips: Enter the measured pressure, atmospheric pressure (default 101325 Pa), fluid density (default 1000 kg/m³ for water), and gravity (default 9.81 m/s²). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: Why subtract atmospheric pressure?
A: Pressure gauges often measure absolute pressure, so we subtract atmospheric pressure to get hydrostatic pressure from the liquid alone.

Q2: What's a typical fluid density?
A: Water is 1000 kg/m³ at 4°C. Oil ranges 800-950 kg/m³, while acids can be 1200-1800 kg/m³.

Q3: When would gravity value change?
A: For extreme precision or at different elevations (gravity varies slightly with latitude and altitude).

Q4: How do I measure tank pressure?
A: Use a pressure transmitter installed at the tank bottom, ensuring proper calibration.

Q5: Does this work for pressurized tanks?
A: No, this formula is for open tanks. For pressurized tanks, you need additional vapor pressure measurements.