Rotary screw air compressors (oil-lubricated) are most commonly used air compressor for medium to high flow nitrogen applications.

Rotary screw air compressors are positive displacement compressors. The most widely used compressor in industry is the single stage oil lubricated rotary screw air compressor. The rotary screw compressor has two rotors encased within a housing, known as an air end. Ambient air enters the air end where the air is compressed by the two rotors. Oil is injected into the air end to create a seal as well as for cooling purposes.

Maintenance is simple on a rotary screw air compressor. Preventative maintenance typically includes changing of air filters; oil filters; air/ oil separator; and oil.

There are numerous designs available for controlling the capacity of the air compressor. The units can operate in either modulation; load/ no load; as well as variable speed. Variable speed technology is the most energy efficient method of operating an air compressor at partial loads.

• Continuous duty: Rotary screw air compressors are designed for continuous duty making them an excellent fit for nitrogen generators that operate around the clock. These compressors can also operate under partial load conditions based on their load/ no load design.
• Energy efficiency: Rotary screw air compressors have many control options which match the needs of the customer. These units are available in various control methods to best match the application. If the nitrogen demand varies greatly a variable speed air compressor may be an option.
• High pressure applications: Many customers require high pressure nitrogen (~200 psig). This can be achieved by simply utilizing a high pressure rotary screw feed air compressor, eliminating the need for high pressure booster compressors.
• Oil-Free Option: Rotary screw air compressors are also available for critical applications that cannot tolerate the possibility of oil contamination.