How Rotary Screw Air Compressors Work
A rotary screw air-end or element has twin rotors, which include male and female parts rotating in opposite directions. Air fills the space between the rotors and, as they rotate, the volume between them and the surrounding housing decreases, squeezing or compressing the air into a smaller space. The length, pitch of the screw, and the form of the discharge port collectively determine the pressure ratio. Beyond that, there are no valves, or other mechanical forces that can cause unbalance, which allows a screw compressor to operate at high speeds while combining a large flow rate with small exterior dimensions – it packs a good punch for its size.
Benefits of Rotary Screw Air Compressors
Rotary screw compressors typically are used for continuous, commercial and industrial applications. Here are some of the primary advantages of a rotary screw compressor:
1. Lower noise outputs to meet OSHA requirements
2. Significant reduction in weight, typically by 50 percent
3. Easier maintenance due to fewer wearing parts to maintain or replace
4. Shock-less, non-wearing compression technology
5. Simplified maintenance procedures
6. Extremely low oil-carryover (as little as 3 ppm)
7. Less overall oil consumption
8. Proven reliability in harsh environments
9. Smaller physical footprint, typically by 50 percent
10. No “unbalanced” forces, less vibration transfer
11. Less heat generation
12. Zero reduction in capacity over time
Types of Rotary Screw Air Compressors
Rotary screw air compressors are also available in two primary applications: oil free and oil injected. Here’s a breakdown:
Oil Free – External gears synchronize the position of the counter-rotating screw elements, and, because the rotors do not come in contact and create friction, no lubrication is needed within the compression chamber. As a result, the compressed air is oil-free. Precision engineering within the housing keeps pressure leakage (and drops) from the pressure side to the inlet at a minimum. And because the internal pressure ratio is limited by difference in air temperature between the inlet and discharge ports, oil-free screw compressors are frequently built with several stages and inter-stage cooling to maximize the pressure reach. The gearbox driving the mechanism does contain lubricants; oil-free refers to the compression chamber itself, and the delivered air is free of foreign contaminants beyond those found inherently in the air that passes through the intake.
Oil-Lubricated – In liquid-injected rotary screw air compressors, a liquid is injected into the compression chamber to cool and lubricate the compressor elements moving parts, to cool the air being compressed in the chamber, and to help minimize leaks from returns into the chamber during discharge. While oil is the most common liquid used today because of its lubricating and sealing properties, water and other polymers are sometimes used. The oil is then separated and passes through a filter and cooler before it cycles back into the process again. The compressed air can still be hot and often times is run through a cooler, depending on end usage.
Oil-Lubricated Rotary Screw Air Compressors Series
G (VSD) & GX oil-lubricated screw compressor
![g and gx rotary screw air compressors series]()
G (VSD) & GX oil-lubricated screw compressor
Our G and GX oil-injected rotary screw compressors are designed for reliability and efficiency. Will operate continuously in the harshest environments, avoiding costly downtime and production delays
Our G and GX oil-injected rotary screw compressors are designed for reliability and efficiency. Will operate continuously in the harshest environments, avoiding costly downtime and production delays
Our G and GX oil-injected rotary screw compressors are designed for reliability and efficiency. Will operate continuously in the harshest environments, avoiding costly downtime and production delays
GA (VSD+) oil-lubricated screw compressors
![ga vsd+ rotary screw air compressors]()
GA (VSD+) oil-lubricated screw compressors
GA & GA+ (5-500 kW)
GA VSD (37 -315 kW)
GA VSD+ (7-75 kW)
Our market-leading GA oil-injected rotary screw compressor delivers outstanding performance, high productivity and low cost of ownership - even in the harshest environments
GA & GA+ (5-500 kW)
GA VSD (37 -315 kW)
GA VSD+ (7-75 kW)
Our market-leading GA oil-injected rotary screw compressor delivers outstanding performance, high productivity and low cost of ownership - even in the harshest environments
GA & GA+ (5-500 kW)
GA VSD (37 -315 kW)
GA VSD+ (7-75 kW)
Our market-leading GA oil-injected rotary screw compressor delivers outstanding performance, high productivity and low cost of ownership - even in the harshest environments
GR 110-200 two-stage rotary screw air compressor
![gr rotary screw air compressors]()
GR 110-200 two-stage rotary screw air compressor
GR oil-injected 2-stage air compressors provide a reliable air supply of up to 20 bar for high pressure applications in the toughest working conditions. Often used as mine compressor
GR oil-injected 2-stage air compressors provide a reliable air supply of up to 20 bar for high pressure applications in the toughest working conditions. Often used as mine compressor
GR oil-injected 2-stage air compressors provide a reliable air supply of up to 20 bar for high pressure applications in the toughest working conditions. Often used as mine compressor
Shop Online
Shop Online
You can now buy Atlas Copco compressors online! Our online store features compressors from 2-50HP, providing compressed air flows up to 250 CFM, with and without dryers.
You can now buy Atlas Copco compressors online! Our online store features compressors from 2-50HP, providing compressed air flows up to 250 CFM, with and without dryers.
Oil-Free Rotary Screw Air Compressors Series
AQ water-injected oil-free screw compressors
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AQ water-injected oil-free screw compressors
The AQ water-injected screw compressors meet your need for pure oil-free air. They deliver best in class energy efficiency for applications that demand reliability and purity
The AQ water-injected screw compressors meet your need for pure oil-free air. They deliver best in class energy efficiency for applications that demand reliability and purity
The AQ water-injected screw compressors meet your need for pure oil-free air. They deliver best in class energy efficiency for applications that demand reliability and purity
ZR & ZT (VSD) oil-free air rotary screw and tooth compressors
![ZR and ZT Oil-Free Rotary Screw Air Compressor]()
ZR & ZT (VSD) oil-free air rotary screw and tooth compressors
ZR & ZT
Meet our top of the range oil-free compressors that combine top technology to deliver outstanding performance for you at every level
ZR & ZT
Meet our top of the range oil-free compressors that combine top technology to deliver outstanding performance for you at every level
ZR & ZT
Meet our top of the range oil-free compressors that combine top technology to deliver outstanding performance for you at every level
ZE & ZA ( VSD) low pressure oil-free screw compressors
![ZE and ZA Oil-Free Rotary Screw Air Compressor]()
ZE & ZA ( VSD) low pressure oil-free screw compressors
ZE&ZA (VSD): high-performance low pressure oil-free air compressors
ZE/ZA fixed and variable speed drive (VSD) low-pressure oil-fee air compressors: high quality performers with a robust design.
ZE&ZA (VSD): high-performance low pressure oil-free air compressors
ZE/ZA fixed and variable speed drive (VSD) low-pressure oil-fee air compressors: high quality performers with a robust design.
ZE&ZA (VSD): high-performance low pressure oil-free air compressors
ZE/ZA fixed and variable speed drive (VSD) low-pressure oil-fee air compressors: high quality performers with a robust design.
ZD (VSD) oil-free medium pressure screw compressor with high pressure piston booster
![zd high pressure oil free rotary screw air compressor with piston booster]()
ZD (VSD) oil-free medium pressure screw compressor with high pressure piston booster
ZD compressor and booster combination with energy saving VSD option.
Whether you need medium, high pressure or both, the ZD (VSD) high pressure screw compressor and booster delivers 100% oil-free dry air or nitrogen.
ZD compressor and booster combination with energy saving VSD option.
Whether you need medium, high pressure or both, the ZD (VSD) high pressure screw compressor and booster delivers 100% oil-free dry air or nitrogen.
ZD compressor and booster combination with energy saving VSD option.
Whether you need medium, high pressure or both, the ZD (VSD) high pressure screw compressor and booster delivers 100% oil-free dry air or nitrogen.
