Air Supply UK: Specialist Compressed Air Engineers

Published: 01/08/2022

A guide to choosing the right rotary screw compressor for your business

Rotary screw air compressors are in high demand, which means there’s lots of choice out there. But what type of compressor is right for your business? Choosing the right one shouldn’t be a headache. 

We’ve put this guide together to help you find the perfect compressor for your business and its applications.   

What is a rotary screw air compressor? 

A rotary screw air compressor is a machine that compresses air using a rotary motion. Inside the air compressor are two enmeshed helical screws that spin rapidly. Captured air travels down the axis of these rotary screws and the space where air is trapped becomes smaller and smaller. 

The compressed air is then discharged from an outlet, often situated on the opposite side of the machine’s air inlet valve. Compressed air is used straight away, stored, dried or passes through air filters to remove contaminants.

What can rotary screw compressors be used for?

The industrial application of compressed air systems is far-reaching and sector-wide. You can find them inside manufacturing complexes, construction sites and packaging plants. Rotary screw air compressors used to power tools and have many other industrial applications. If necessary, compressors can even run 24 hours a day, seven days a week, year after year. Making them good fits for applications that require high CFM and continuous air demands (or a 100% duty cycle). Furthermore, they’re ideal for operations that also need very clean air.

Here are some sectors that typically use air compressors: 

  • Food processing 
  • Packaging lines 
  • Construction sites (particularly for mobile units) 
  • Auto painting and paint lines 
  • Manufacturing 
  • Pneumatic conveyor systems

The benefits of rotary screw air compressors 

Rotary screw air compressors have many benefits over their counterparts. We’ve listed some of the key features and how they can benefit your business and its applications. 

Low energy costs

Variable speed drive compressors are suitable for work environments where air demands vary throughout operations. VSD compressors account for 35% of energy savings. Fixed speed rotary air compressors are also more energy efficient if your operations need a consistent, continual air flow.      

Easy maintenance 

Air filters should be changed around every 2,000 hours of use. Plus, oil-injected rotary screw air compressors need annual maintenance. Of course, if your compressor is oil free, this kind of maintenance is unnecessary. Always check the manufacturer’s manual for specific maintenance guidelines. Like all plant, compressors require regular inspections and consistent maintenance to perform at optimal levels. 

Generally, inspections should be conducted every six months. 

Safe to operate

Rotary air systems are safe to operate.

Quiet operation

Consistent exposure to noise is a health and safety risk for staff. Not only does noise damage ears over time, it makes communication between staff more difficult. Rotary air screw compressors produce 65 – 75 dBA, compared to piston type air compressors that generate 80 – 85dBA. Gear drives are the best choice for reducing noise operations. 

Longer lifespan

Rotary screw air compressors boast superior longevity in comparison to piston compressors. In fact, rotary screw compressors last between 60,000 to 80,000 hours, and piston (or reciprocating) compressors require a rebuild after 10,000 hours. 

Customisable to your applications

As well as great reliability and durability, Variable Speed Drive technology makes rotary screw compressors flexible to most applications. VSD compressors adjust motor speeds to fluctuating air demands. Unlike fixed speed compressors that are either on or off.  

Different drive types are also available. The aforementioned gear drives make rotary screw air compressors quieter. The easier installation and low maintenance of belt drives make them ideal for smaller operations. Direct drives are even quieter than gear drives and are much more efficient. 

You can also choose an oil-free compressor or one that achieves higher pressures with lubricating oil. Again, this depends on your operations. If you need cleaner air, oil-free compressors are the best choice. Alternatively, oil-injected compressors produce more air but of lower quality.  

Key factors to consider 

Although they function in the same way, different air compressors are more suitable for specific tasks and operations. Therefore, choosing the right rotary screw compressor depends on multiple features that you should consider: 

  • Energy efficiency – industrial, manufacturing and construction operations require enough power for full optimisation but energy costs can vary considerably.
  • Performance – different types of compressors have varied flow rates and operate at different speeds. This can affect energy consumption and performance in many ways
  • Maintenance – good maintenance improves longevity of any type of plant machinery. Air compressors are no different. However, you want a reliable compressor that is guaranteed to work well without the need for constant high maintenance demands and repairs. 
  • Manufacturer – what services are on offer? Does your chosen manufacturer design and install the compressor? Do they offer regular services? What’s their policy on repairs etc.

We hope this blog post has helped you out! If you need any more help in deciding which compressor is best for your operations, give us a call




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