Air Cannon Calculator: Air Consumption and Compressor Size

How much compressed air a bank of air cannons (air blasters) uses, and what the compressor has to deliver.

Calculated from standard textbook formulas, with every step shown. The formulas are fixed, so the working does not need checking: what matters is the numbers you type in. Use these calculators only if you are competent to choose the inputs (loads, material strength, dimensions, supports) and check your units and assumptions. For learning and checking your own working: design and sign-off are for a qualified engineer. Drafting Central does not store the numbers you type.

How this calculator works

An air cannon stores compressed air in a tank and releases it in a sudden blast to break up material that sticks in a hopper, chute or duct. Every shot empties the tank, so the air used is the tank volume times the pressure, expressed as free air at atmospheric pressure.

Multiply by the shots per hour and the number of cannons for the average demand, and add an allowance for leaks and peak firing to size the compressor. The calculator also gives the time the compressor needs to refill a tank, which sets how often a cannon can fire.

Formulas used

  • V_{air} = \frac{V\,p}{p_{atm}}
  • Q = N\,\frac{V_{air}\,s}{1000}\;\mathrm{m^3/h}
  • \mathrm{CFM} = Q\,\frac{35.3147}{60}

Worked example

With the default numbers in the calculator above:

  1. Free air used in one shot: 888.2 L of free air
  2. Free air for one blaster per hour: 5.329 m³/h
  3. Free air for all the blasters: 85.27 m³/h (23.69 L/s)
  4. The same in cubic feet per minute: 50.19 CFM
  5. Compressor free air delivery to ask for: 29.61 L/s (106.6 m³/h)
  6. Time for your compressor to refill one tank: 29.61 s
  7. Most shots per hour your compressor can supply: 121.6 shots/h in total (you need 96)

Change the numbers in the calculator to see the full working, every step, for your own case.

Common questions

Is the pressure gauge or absolute?

Gauge pressure, as read on the cannon regulator. The air used is the tank volume times the gauge pressure over atmospheric pressure.

Why add an allowance?

Leaks, pipe losses and several cannons firing together all add to the average. A typical allowance is 20 to 30 percent, but it is an assumption, so use your own figure.

Does a bigger receiver help?

Yes. The cannons fire in short bursts. A receiver between the compressor and the cannons supplies the burst and lets a smaller compressor run steadily.

Related calculators

Further reading: White, Fluid Mechanics; Munson, Young and Okiishi, Fundamentals of Fluid Mechanics; Crane Technical Paper 410.

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