Oil Free Air Compressors: Best Choice for Pure Air
Two Stage Oil Free Rotary Screw Compressors DS – Series
CompAir has extended its Oil Free rotary screw compressor range with the new DS37-DS150 fixed and variable speed series.
What it is:
Class Zero Oil FREE Rotary Screw Compressor
Nominal Power from 37-150 kW
Capacity of up to 25.9 m³/min (@ 7 bar g)
Complementing the established 160 to 315 kW model range
Fixed Speed and Variable Speed (RS) Models
Air-cooled
Numerous Further Options
We are pleased to announce the launch of new oil-free rotary screw compressor models, complementing the established CompAir D-Series range and delivering reliability, dynamic efficiency, lower operating costs, and high-quality oil-free compressed air.
The new models are:
Class Zero Oil Free Rotary Screw Compressor
Nominal Power from 37-150 kW
Capacity of up to 25.9m3/min (@ 7 bar g)
Complementing the established 160 to 315kW model range
Fixed Speed and Variable Speed models
Air cooled
Numerous Further Options
Highest productivity
Oil Free Class 0 certified air delivered for the most demanding industries
Intuitive Controller with extensive events history and advanced connectivity
The DS Series range from CompAir is able to withstand the harshest environments and 46°C maximum ambient temperature, reducing unplanned shutdowns caused by high heat, and increasing productivity.
Optimum efficiency
The range features a robust airend with precision machined gears, oversized bearings, stainless steel air seals, and unique labyrinth oil seal design to eliminate the risk of internal leaks.
Hot Air Discharge option for lowest pressure dew points without additional energy consumption via HOC dryer
Maximum reliability
Patented Ultracoat™ treatment of rotors and internalparts of compression chamber to avoid corrosion
Stainless Steel robust piping design on the cold side
Efficient inlet air filter for the best care of the air compressed path
IP65 electrical fittings and control panel
Value added services
Easy access to main components
No special tools required
8000 hours coolant change interval
Free iConn inside. A smart, proactive real-time online monitoring service that allows operators to manage the performance of the system through invaluable data statistics and insights, iConn will alert users should a potential issue with the compressed air system arise.
Service and warranty programs
💧 Oil-Free vs Oil-Lubricated
Oil-free air compressors produce compressed air without oil entering the air stream. This is crucial in applications where even trace oil contamination can:
spoil food products
compromise pharmaceuticals
impact painting, electronics, and semiconductor processes
This purity is typically certified to ISO 8573-1 Class 0, meaning zero oil contamination tolerance in the compressed air.
🔩 Two-Stage Rotary Screw Design
A two-stage rotary screw compressor works by compressing air in two stages instead of one. This improves efficiency and cooling while maintaining high purity. For oil-free models, manufacturers design the compression elements so no oil is used for sealing or lubrication in the airend — resulting in truly clean, pure compressed air.
Benefits of this design include:
100 % pure air (Class 0) – no oil in the compressed air line.
Lower total cost of ownership due to improved efficiency and lower maintenance.
Suitable for sensitive industries: food & beverage, pharmaceutical, electronics, medical air, etc.
Often available with fixed speed and variable speed (VSD) options to optimise energy use.
📌 DS-Series Specifics
Manufacturers such as CompAir and Hitachi/Sullair offer DS-Series two-stage oil-free rotary screw compressors with features like:
37–150 kW power range for air-cooled models.
Very high air discharge capacity (up to ~25.9 m³/min at 7 bar).
Durable design for harsh environments and high ambient temperatures.
Intelligent controllers for easy operation and remote monitoring.
These units are engineered to deliver pure, reliable compressed air while maximising uptime and efficiency — ideal for industrial environments where air quality cannot be compromised.
📌 Summary
Oil-free air compressors — especially two-stage rotary screw types like the DS Series — are excellent choices when you need pure compressed air with zero oil contamination. They are engineered for demanding industries, offering dependable performance, high efficiency, and compliance with strict purity standards (ISO Class 0).
