Rotary Screw
Air Compressors
Built for continuous, pulse-free air. Rotary screw compressors run at 100% duty cycle where piston machines have to rest, making them the workhorse of any site that needs air all shift. From 4 to 250 kW, fixed speed or VSD.
A rotary screw compressor compresses air using two interlocking helical rotors that turn inside a sealed housing, squeezing trapped air into a smaller space as it moves towards the outlet and delivering a continuous, pulse-free supply.
That continuous action is what sets screw compressors apart from piston machines. They run cooler and quieter, they are rated for 100% duty cycle, and they hold steady pressure under sustained demand. Available oil-injected or oil-free, in fixed speed or variable speed drive form, and as single or two-stage platforms, the rotary screw is the standard choice for industrial sites that need air all day.
Where Screw Compressors Fit
Any operation that needs a steady, sustained air supply rather than short bursts is a screw compressor application.
Continuous Production
Manufacturing lines that run all shift need air without interruption. Rotary screw compressors are built for 100% duty cycle, unlike piston machines that need to rest and cool.
Multi-Tool Workshops
Where several air tools draw at once, a screw compressor holds steady pressure across the demand swings that would stall a smaller piston unit.
Variable Demand Sites
Facilities where air use rises and falls through the day. A variable speed drive screw compressor matches output to demand and cuts the energy wasted on idle running.
Clean-Air Processes
Food, pharmaceutical, and electronics work that cannot tolerate oil. Oil-free rotary screw compressors deliver Class 0 air at the volumes these processes need.
Energy-Critical Sites
Where electricity is the largest line in the air budget. Modern screw platforms with VSD and heat recovery cut running cost well below an ageing fixed-speed machine.
Multi-Site Estates
Groups standardising plant across locations. A common screw platform simplifies spares, training, and service across every site in the estate.
Screw vs Piston
The choice between rotary screw and piston compression comes down to how hard and how often you use air. For sustained industrial demand, the rotary screw wins on nearly every measure that affects running cost and reliability.
| Factor | Rotary Screw | Piston |
|---|---|---|
| Duty cycle | 100%, continuous | Intermittent, needs rest |
| Noise | Low, smooth running | High, pulsing |
| Air delivery | Steady, pulse-free | Pulsed |
| Best flow range | Medium to high, sustained | Low, occasional use |
| Energy efficiency | High, especially with VSD | Lower at sustained load |
| Service life | Long under continuous load | Shorter under heavy duty |
Screw Compressor Range
Our rotary screw platforms. All units supplied, installed, and maintained by Airmech with PSSR compliance included.
CompAir Rotary Screw
Oil-injected and oil-free rotary screw compressors with fixed speed, variable speed drive, and two-stage platforms. The core range for continuous industrial demand.
View range and specificationsABAC Rotary Screw
Compact rotary screw compressors for workshops, dental practices, and light industrial use where a piston machine cannot keep up but a large industrial unit is more than needed.
View range and specificationsBuy and Maintain
with One Partner
A rotary screw compressor is a long-term asset that rewards correct sizing and disciplined servicing. We size it to your real demand, install and commission it, then maintain it under one planned maintenance contract. One partner accountable for the purchase, the upkeep, and PSSR compliance across every site you run.
Frequently Asked Questions
What is a rotary screw compressor and how does it work?
A rotary screw compressor compresses air using two interlocking helical rotors, called the male and female screws, turning inside a sealed housing. As the rotors turn, air drawn in at one end is trapped between the screws and the housing and squeezed into a progressively smaller space as it moves towards the outlet. The result is a continuous, pulse-free supply of compressed air, which is why screw compressors suit applications that run all day.
What is the difference between a screw compressor and a piston compressor?
A piston compressor uses reciprocating pistons and is best for intermittent, lower-volume use, but it runs hot and noisy and needs to rest between cycles. A rotary screw compressor uses continuously rotating screws, runs cooler and quieter, and is rated for 100% duty cycle, so it can supply air without stopping. For any site that needs a steady, sustained air supply, a screw compressor is almost always the right choice.
Should I choose a fixed speed or variable speed screw compressor?
A fixed speed compressor runs at a constant motor speed and is most efficient when your air demand is steady and close to the compressor's full output. A variable speed drive (VSD) compressor changes motor speed to match demand, which removes the energy wasted on idle running and suits sites where air use rises and falls through the day. Where demand varies, a VSD machine typically pays back the price difference in energy savings.
What size screw compressor do I need?
Sizing depends on your air demand in litres per second or cubic feet per minute, your required pressure in bar, and how that demand varies across the day. Undersizing causes pressure drops and stalled tools, while oversizing wastes energy and capital. We assess your actual demand profile, ideally with data logging, before recommending a size so you buy the right machine rather than the biggest one.
Do you supply and maintain screw compressors?
Yes. Airmech is an authorised distributor for CompAir and ABAC rotary screw compressors from 4 to 250 kW, covering oil-injected, oil-free, fixed speed, VSD, and two-stage platforms. We install, commission, and maintain them under planned maintenance contracts with PSSR compliance included, so one partner covers the purchase and the upkeep across single sites or a national estate.
Need a Screw Compressor?
Tell us your air demand, pressure, and how it varies through the day. We will size the right rotary screw compressor, fixed speed or VSD, and quote it with installation and servicing.