1. What is Tank Level Calculator?

Definition: This calculator determines the liquid level in a tank by measuring the hydrostatic pressure at the bottom, adjusted for the specific gravity of the liquid.

Purpose: It is used in various industries to monitor liquid levels in tanks, such as water storage, fuel tanks, or chemical containers, ensuring accurate inventory and safety.

2. How Does the Calculator Work?

The calculator uses the following formula:

Formula: $$\text{Liquid Level (in)}=\frac{\text{Pressure (inH2O)}}{\text{Specific Gravity}}$$ $$\text{Pressure (inH2O)}=(\text{Pressure at Bottom}-\text{Pressure at Top})\times \text{Conversion Factor}$$ Where:

• $\text{Liquid Level}$: Height of the liquid (in, ft, m, cm)
• $\text{Pressure at Bottom}$: Measured pressure at the tank bottom (psi, bar, Pa, inH2O)
• $\text{Pressure at Top}$: Measured pressure at the tank top (0 for vented tanks) (psi, bar, Pa, inH2O)
• $\text{Specific Gravity}$: Ratio of the liquid's density to that of water (unitless)

Unit Conversions:

• Pressure:
  • 1 psi = 27.71 inH2O
  • 1 bar = 401.463 inH2O
  • 1 Pa = 0.00401463 inH2O
  • 1 inH2O = 1 inH2O
• Liquid Level:
  • 1 in = 1 inch
  • 1 ft = 12 in
  • 1 m = 39.3701 in
  • 1 cm = 0.393701 in

Steps:

• Enter the Pressure at Bottom and select its unit (psi, bar, Pa, inH2O).
• Enter the Pressure at Top (0 for vented tanks) and select its unit (psi, bar, Pa, inH2O).
• Enter the Specific Gravity of the liquid (default 1.0 for water).
• Convert both pressures to inH2O and calculate net pressure due to liquid level.
• Calculate the liquid level in inches using the formula.
• Convert the result to the selected unit (in, ft, m, cm).
• Display the result, using scientific notation for values less than 0.001, otherwise with 4 decimal places.

3. Importance of Tank Level Calculation

Calculating Tank Level using pressure is crucial for:

• Inventory Management: Accurately monitoring liquid quantities in storage tanks.
• Safety: Preventing overfilling or running dry, which can damage equipment or cause spills.
• Process Control: Ensuring consistent liquid levels in industrial processes like chemical manufacturing.

4. Using the Calculator

Examples:

• Example 1: For Pressure at Bottom = 3 psi, Pressure at Top = 0 psi, Specific Gravity = 1.0, results in inches:
  • Convert pressure: $3\times 27.71=83.1300\text{inH2O}$, Top pressure = 0
  • $\text{Liquid Level}=\frac{83.1300}{1.0}=83.1300\text{in}$
• Example 2: For Pressure at Bottom = 7.5 psi, Pressure at Top = 100 bar, Specific Gravity = 1.02, results in meters:
  • Convert pressures: Bottom = $7.5\times 27.71=207.8250\text{inH2O}$, Top = $100\times 401.463=40146.3000\text{inH2O}$
  • Net pressure: $207.8250-40146.3000=-39938.4750\text{inH2O}$
  • Error: Net pressure is negative, indicating an invalid input scenario.
• Example 3: For Pressure at Bottom = 1000 Pa, Pressure at Top = 0.5 psi, Specific Gravity = 0.8, results in centimeters:
  • Convert pressures: Bottom = $1000\times 0.00401463=4.0146\text{inH2O}$, Top = $0.5\times 27.71=13.8550\text{inH2O}$
  • Net pressure: $4.0146-13.8550=-9.8404\text{inH2O}$
  • Error: Net pressure is negative, indicating an invalid input scenario.

5. Frequently Asked Questions (FAQ)

Q: What is hydrostatic pressure in a tank?
A: Hydrostatic pressure is the pressure exerted by a liquid at the bottom of a tank due to the weight of the liquid column above it.

Q: Why does specific gravity matter?
A: Specific gravity adjusts the pressure measurement for the density of the liquid, ensuring accurate level calculation for liquids denser or lighter than water.

Q: How do I measure pressure in a pressurized tank?
A: Use pressure gauges at the top and bottom of the tank, ensuring units are consistent or converted, then subtract the top pressure from the bottom pressure to isolate the pressure due to the liquid level.

6.Reference

https://www.hunker.com/12322279/how-to-calculate-tank-level-using-pressure/

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