Blowing with compressed air is a common efficiency problem in industrial plants. In dusty environments, things like conveyor belts, motors and pulleys need to be kept clear of dust and debris or problems will shut down production. So it is not uncommon to see plant personnel using air wands, or worse, installing continuous blowing to prevent any problems
You may have wondered why we don’t typically see compressed air blowing used at home, say for blowing leaves off your lawn. Consider a large leaf blower that puts out 520 cfm, this device would consume about 12 amps at 120 volts, about 1.5 kW ( 2 horsepower) costing about 15 cents in electricity per hour.
A similar gas powered blower, like the one in the picture, uses a 2.5 hp motor and weighs 27 pounds. But if you wanted to do the same job using an air compressor, producing at 100 psi, you would need a 125 hp air compressor consuming 105 kW, and weighing 3,500 pounds, costing about $10.50 per hour in electricity. Seems ridiculous doesn’t it? Something we would never do, but time and time again, compressed air auditors find unfortunate compressed air end uses in industrial plants — things that use 100 psi compressed air for a job that only needs a few ounces of air pressure, something that could be supplied by a low pressure blower. Why is it done? Typically, the compressed air user and designer doesn’t have to pay the electrical bill. So why not just hook up to the existing compressed air system?
If you want to reduce your compressed air costs, you should consider the cost of blowing applications like this and work the numbers. You should realize that compressed air blowing typically costs substantially more that low pressure flowing. You might find you can reduce the cost of your compressed air substantially and not blow your profits away on wasted energy.
Some common low pressure compressed air applications that could be done more efficiently with low pressure:
- Blow wands for cleaning
- Conveyor cleaning
- Cooling of motors
- Agitating liquids
- Drying of product or conveyors
- Ventilation of cabinets
- Aeration of product
- Transportation of powders