Air Lift Pump Input Form
Example Data Table
| Case | Submergence m | Delivery lift m | Riser mm | Air flow m3/min | Air water ratio | Expected use |
|---|---|---|---|---|---|---|
| Small sump | 8 | 3 | 50 | 0.8 | 10 | Shallow excavation |
| Deep well | 22 | 8 | 75 | 2.8 | 9 | Well dewatering |
| Slurry lift | 30 | 12 | 100 | 5.5 | 12 | Sand laden water |
Formula Used
Submergence ratio: SR = submergence depth / total pump length.
Total pump length: L = submergence depth + delivery lift.
Estimated water flow: Qw = Qa × 60 ÷ R × correction factor.
Required air flow: Qa = Qw ÷ 60 × R ÷ correction factor.
Riser velocity: Vw = Qw / pipe area.
Friction head: Hf = K × Vw² / 2g.
Minimum gauge pressure: P = density × g × submergence / 100000 + allowance.
Compressor power estimate: kW = P1 × free air flow × ln(P2/P1) ÷ efficiency.
These formulas give planning estimates. Final selection should be checked against pump tests, compressor curves, pipe losses, and site conditions.
How to Use This Calculator
- Enter the submergence depth from static water level to air injection point.
- Enter the discharge lift above static water level.
- Add riser pipe and air line inside diameters.
- Choose whether to calculate water flow or required air flow.
- Adjust air to water ratio, efficiency, slip, and solids allowance.
- Press Calculate to view results above the form.
- Download the CSV or PDF report for project records.
Construction Air Lift Pump Planning Guide
Purpose
An air lift pump moves water by injecting compressed air near the lower end of a riser pipe. The air reduces the average density inside the pipe. The heavier surrounding water then pushes the lighter air water mixture upward. This method is useful where mechanical pumps may clog, overheat, or suffer damage. Construction teams use it for wells, shafts, caissons, bored piles, slurry trenches, and temporary sumps.
Key Site Inputs
The main input is submergence. A deeper injection point gives a stronger driving force. Delivery lift also matters. A high discharge point reduces useful flow. The pipe diameter controls velocity. A narrow riser increases friction. A wide riser may need more air to start stable lifting. Air line size affects pressure loss and compressor loading.
Performance Checks
The calculator compares air flow, water flow, pressure, velocity, and power. It uses correction factors for slip, solids, and practical efficiency. These factors reflect real site losses. Sand, silt, bentonite, or gravel can lower output. Long hoses and fittings can also increase compressor demand. For reliable operation, the submergence ratio should normally be high enough. Many field setups work better when more than half of the riser length is submerged.
Practical Construction Use
Use this tool during early planning and method statement preparation. Compare several riser sizes before ordering equipment. Check whether the compressor can deliver enough free air at the required pressure. Review the riser velocity when pumping dirty water. Low velocity may allow particles to settle. High velocity may cause wear, vibration, and excess losses. The daily volume result helps estimate dewatering capacity during shifts. Keep a safety allowance for leaks, hose bends, filters, and changing groundwater levels.
Engineering Caution
Air lift pump behavior is multiphase and site specific. Exact capacity depends on air distribution, nozzle position, pipe roughness, and water conditions. Use manufacturer data and field testing for final design. This calculator supports screening, comparison, and documentation. It does not replace professional engineering judgment.
FAQs
What is an air lift pump?
An air lift pump uses compressed air to reduce fluid density inside a riser pipe. Surrounding water pressure pushes the mixture upward.
Where is it used in construction?
It is used in wells, shafts, bored piles, sumps, caissons, slurry trenches, and locations where solids may damage standard pumps.
What is submergence ratio?
It is the submerged length divided by total lift length. Higher submergence usually improves flow stability and pumping capacity.
Why does compressor pressure matter?
The compressor must overcome water pressure at injection depth, pipe losses, fittings, and an allowance for field variation.
What is air to water ratio?
It estimates how many cubic meters of free air are needed for each cubic meter of water lifted under practical conditions.
Can this calculator handle slurry?
Yes. Use the solids allowance and density fields. For abrasive slurry, also check pipe wear, velocity, and field test results.
What riser velocity is practical?
Many temporary systems aim for moderate velocity. Very low velocity may settle solids. Very high velocity can increase losses and wear.
Is the result final for design?
No. It is a planning estimate. Final design should use site testing, equipment curves, and professional engineering review.