An oil-injected screw air compressor uses oil for three simultaneous functions inside the compression chamber: sealing the clearance between the screw rotors, cooling the compression heat, and lubricating the rotating elements. Because the oil forms a hydrodynamic film that prevents metal-to-metal contact, the compression chamber has no wearing parts — the screw and star wheel never touch directly during operation. This design achieves volumetric efficiency above 95% and delivers the highest energy efficiency per unit of air produced among industrial compressor types, at a capital cost significantly lower than oil-free alternatives.
Every RAYDAFON oil-injected screw compressor is engineered around a single-screw compression structure, an IE4 permanent-magnet variable-frequency drive, and a hydrodynamic oil film that eliminates wear. The result is stable air volume over decades of continuous service — not marketing claims, but measured performance.
Twelve compression cycles per single screw rotation — the highest efficiency design in rotary screw compressors.
The oil film prevents direct rotor contact — less than 5% air volume loss after five years of continuous operation.
Permanent-magnet variable-frequency motor — the highest international efficiency class for industrial motors.
The screw rotates once and achieves twelve compression cycles. With volumetric efficiency above 95% and no direct rotor contact, this architecture delivers the highest air output per kilowatt in its class — and eliminates the wear that shortens the life of conventional compressor designs.
The IE4 motor — the highest energy efficiency class available for industrial motors — is paired with a variable-frequency drive that continuously matches motor speed to actual air demand. The result is minimal energy waste at partial loads, where most compressors run most of the time. See all RAYDAFON compressors →
Oil lubrication creates a continuous hydrodynamic film between the screw and star wheel. At operating speed, the two elements never touch — no belt, no coupling, no gearbox adjustment. After five years of typical use, air volume declines less than 5% and the air end requires no major service.
The RD-OI air end runs with such low vibration that a coin placed on the housing remains standing during full-load operation. This reduces structural stress on piping, foundation, and building elements — and eliminates the noise complaints common to piston-type compressors.
| Parameter | Specification |
|---|---|
| Working Pressure | 7-15 bar (0.7-1.5 MPa) |
| Compression Structure | Single-screw, oil-injected |
| Volumetric Efficiency | 95%+ |
| Motor Type | IE4 permanent-magnet variable-frequency |
| Air Volume Stability | Less than 5% decline after 5 years |
| Design Service Life | Over 20 years |
| Vibration | Coin-stand test passed at full load |
| Maintenance | Air filter, oil filter, oil separator, oil replacement |
| Voltage | 220V / 380V / 440V (customizable) |
| Certifications | CE, PED, ISO 9001 |
Oil-injected and oil-free screw compressors serve different roles in industrial compressed air systems. The choice depends on whether compressed air contacts the end product or must meet strict oil-free specifications.
Oil-injected screw compressors power the general industrial compressed air systems that underpin automotive workshops, textile plants, mining operations, chemical processing, and construction sites worldwide.
Pneumatic tools, paint booth air supply, tire inflation, and assembly line actuators. See applications →
Air-jet looms, texturing machines, spinning equipment, and dyeing processes.
Pneumatic conveying, process actuators, and general plant air supply.
Rock drills, ventilation actuators, and heavy-duty pneumatic equipment.
Pneumatic actuators, air blow-off, and general workshop air. See electronics →
Jackhammers, pneumatic breakers, and mobile workshop air supply.
Pneumatic grippers, forming actuators, and conveyor blow-off systems. See packaging →
CNC machine tools, sandblasting, spray painting, and workshop tools.
| Application | Recommended Pressure | Typical Air Demand |
|---|---|---|
| Automotive workshop (small) | 7-8 bar | 1-3 m³/min |
| Automotive workshop (large) | 7-8 bar | 3-10 m³/min |
| Textile plant (spinning) | 7-10 bar | 5-20 m³/min |
| Chemical processing | 8-12 bar | 5-15 m³/min |
| Mining operation | 10-15 bar | 10-30 m³/min |
| General fabrication workshop | 7-10 bar | 2-8 m³/min |
Pricing depends on working pressure, flow capacity, voltage configuration, and optional equipment such as dryers, filters, and air receiver tanks. Share your application parameters and RAYDAFON will respond with a factory-direct quote within 12 hours.
Oil-injected screw compressors deliver 7-15 bar air for automotive workshops, pneumatic tools, textile machinery, chemical processing, mining operations, and general manufacturing — wherever reliable compressed air is required without strict oil-free purity specifications.
Oil-injected uses oil for sealing, cooling, and lubrication — higher efficiency, lower capital cost. Oil-free delivers 0 ppm oil content air. Choose oil-injected for general industrial air; choose oil-free when air contacts food, medicine, or electronics.
RAYDAFON oil-injected screw compressors are designed for over 20 years of service life. After five years of typical use, air volume declines less than 5%.
Air filter, oil filter, oil separator, and oil replacement at scheduled intervals. The compression chamber has no wearing parts — the rotor and star wheel are separated by an oil film throughout operation.
Standard configurations ship within 20-35 days. MOQ is 1 unit. Custom configurations may require 40-55 days.
Yes. RAYDAFON supplies complete air treatment packages including refrigerated dryers, desiccant dryers, filters, and air receiver tanks. See after-treatment range →
For a complete compressed air system, pair your oil-injected screw compressor with:
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