Air compressors have some unusual applications – and they can go far beyond simply providing a compressed air supply for power tools.

For example, in recent research co-authored by Samir A Ali, associate professor of agricultural engineering at Banha University in Egypt, a team found that air compressors can improve the efficiency of automated onion-peeling machinery.

In their research paper, the team explain that peeling onions is an important stage in preparing the vegetable for use – not only in home preparation, but in the production of many ingredients, including dehydrated, powdered and canned onions, onion powder and onion rings.

They cite 1997 research by Srivastava et al, who found that blades, assisted by jets of compressed air, could have a significant effect on the performance of automated peeling of onions by slicing more effectively through the outer layers of skin.

In their more recent research, the team found compressed air can improve the process by blowing the shed peel downwards and into a collection basin.

Rinsing with water also worked – but required the water to be replaced every 1-2 hours; with compressed air flushing away the peeled skins, efficiency was raised from 85.45% for large onions, to 88.37% at air pressure of 500kPa.

Although no significant improvement was seen with small onions, whose skins are harder to remove, the researchers concluded: “It could be seen that the proposed improvement systems of peeling efficiency were worthy for medium, large and mixed sizes of bulbs.”