Air compressors do not have a noticeable impact on the concentration of airborne metalworking fluid (MWF) particles in real-world workplaces, according to the Health & Safety Executive (HSE).

The HSE has published new findings, in the form of Research Report 904, which look at airborne particles and dermal deposits from the use of air compressors for removing unwanted MWF from worked surfaces.

In real-world applications, workshops do not see a noticeable rise in airborne particles of MWF, above the normal ambient levels recorded during everyday operations.

This is because most of the droplets of MWF removed from the surface are heavy enough to fall quickly to the workshop floor, or to land as residue on the skin and clothing of the air compressor operator.

Air compressors do, therefore, cause an increase in dermal deposits, but this effect can be reduced by using lower pressure when removing MWF from surfaces, the HSE report adds, while protective clothing can prevent the droplets from reaching the operator’s skin.

Operators can also reduce the number of MWF particles sent their way by compressed air, simply by aiming the air compressor away from them.

“In most circumstances, compressed air forced droplets of MWF in the opposite direction to the operator,” the report notes.

Compressor components may be items of hardware, but they are still benefiting from advances in computer software as scientists look to help engineers make new and even better turbomachinery.

Pumps, fans, turbines and compressor components all fall into the category of machinery, which poses particular difficulties for designers due to the complex nature of the air flows produced during use.

In the US, scientists in Ohio are working to ensure modern computer software is capable of simulating these air flows, so that compressor components can be designed to high standards in the future.

Dr Jen-Ping Chen at Ohio State University is using the processing power of Ohio Supercomputer Centre in his research, and explains the importance of computational fluid dynamics (CFD) for component design.

“The successful combination of CFD simulation and experimentation can greatly supplement the understanding of [the] fundamental fluid behaviour of gas turbine systems,” he says.

In turn, this gives engineers the understanding they need to develop engine components for turbomachinery equipment at a more advanced level of sophistication.

As computers continue to grow in both speed and processing capacity, this is just one example of how the world’s most powerful supercomputers are helping to keep hardware components that have been used for decades on the path towards even better operation.

Air compressors are already used for spraying a wide variety of liquids, many of which have applications in agricultural industries.

But a newly developed all-natural antifreeze formulation could soon allow air compressors to be used to render plants frost-proof.

The recipe, according to University of Alabama professor David Francko, contains “either human food ingredients or [components] used in the human food production chain”.

Yet, once sprayed on to plants, it enhances their natural antifreeze capabilities to a degree comparable with moving them to a climate 200 miles further south.

The discovery is one more example of how sprays can have beneficial effects for agriculture beyond the classic applications of feeding and insecticide.

What’s more, the all-natural formulation could mean the frost-proof spray is suitable for organic farming methods.

For agricultural applications on all scales – from semi-professional vegetable gardens to extensive arable farms – there are air compressors suitable for use in powering plant sprays.

Compact, portable air compressors are ideal for smaller plots, while larger, more powerful alternatives are available for permanent or semi-permanent installation.

One of the principle components in any air compressor is the pump, and over years of development, two main types of pump have evolved. The simpler, but more reliable type of pump is known as the oil lubed pump. This type of pump has proven itself again and again over the years, since it is highly durable, reliable and long-lasting. The only drawback of the oil lubed pump is that the pressurised air that it produces is sometimes not of the best and cleanest quality, which may make the oil lubed pump inappropriate for more technical and exacting applications where extra-clean pressurised air is required.

By contrast, the other type of pump available for air compresssors is known as the oil-less pump. This type of air compressor pump involves a higher level of technical sophistication in order to overcome the lack of lubrication system within the component. However, it can have several drawbacks; it may well be more expensive, it may make a louder noise than an oil lubed pump – and it may last for less time than an oiled lube pump; in its favour, though, the air produced is of better quality.

Air compressors come in all shapes and sizes, but there are broadly two methods of compression, which are known as positive-displacement and negative-displacement. Positive displacement is a form of compression in which air is forced into a chamber whose volume reduces as compression takes place. Piston-driven air compressors use this principle – as do rotary screw compressors, where two helical screws guide air into the chamber and then compress the air as the screws turn. Vane compressors – another type of positive-displacement compressor – use a slotted rotor with varied blade placement to guide air into a chamber and compress it prior to use.

The other method of compression, known as negative-displacement, is used in centrifugal air compressors (which are designed mostly for very large applications). These compressors use centrifugal force generated by a spinning impeller to accelerate and then decelerate captured air. Broadly speaking, most air compressors are either reciprocating piston type, rotary vane or rotary screw.