Oil-Injected Rotary Screw Compressors

Gardner Denver oil-injected rotary screw compressors use AEON synthetic compressor lubricants, such as AEON 9000SP. These are specially formulated compressor oils designed to withstand high operating temperatures, resist oxidation, and provide superior lubrication over extended drain intervals. Using OEM-specified lubricants is critical to maintaining warranty coverage and maximizing airend life.

A lubricant-injected rotary screw compressor is classified as a positive displacement, internal compression machine. It uses two intermeshing helical rotors housed in a casing. As the rotors turn, air is trapped and progressively compressed as the rotor profiles converge. The injected oil film seals rotor clearances and enables near-isothermal compression, differentiating it from oil-free designs that use precision rotor tolerances instead.

Oil-injected rotary screw compressors operate on the positive displacement principle. Two counter-rotating helical rotors mesh together, trapping inlet air in the thread spaces. As the rotors turn, the trapped air volume decreases, increasing pressure. Injected oil seals the rotor clearances, absorbs compression heat to maintain lower discharge temperatures, and lubricates bearings. The compressed air-oil mixture is then separated before the air exits the system.

Gardner Denver oil-injected rotary screw compressors typically operate between 75 and 200 PSIG depending on the model. The L Series and LRS Series cover 75–190 PSIG, while the Electra Saver G2, Electra-Saver II G2, and Electra TS/TSV models operate in the 100–200 PSIG range, accommodating a wide variety of industrial compressed air system requirements.

Fixed speed compressors run the motor at constant speed, loading and unloading to match demand. Variable Speed Drive (VSD) compressors, like the LRS Series, continuously adjust motor speed to exactly match air demand, delivering energy savings of 30–50% in applications with fluctuating demand. Variable displacement models like the Electra-Saver use TurnValve technology to modulate output from 60–100% capacity.

Oil-injected rotary screw compressors are used across a broad range of industries including industrial manufacturing, automotive and body shops, woodworking, hospitals and medical facilities, construction, food and beverage processing, packaging, machine tools, and amusement parks. Their continuous-duty capability, energy efficiency, and broad HP range make them the preferred compressed air source for general industrial environments.