Air enters the enclosed volume (V-shaped space) formed by the rotor flutes and the casing through the intake port; as the rotors rotate, this volume expands, completing the intake process. As rotation continues, the flute space is cut off from the intake port, trapping the air within a sealed chamber formed by the rotors and the casing. The rotor meshing point moves toward the discharge end, causing the enclosed volume to gradually decrease; the air is forcibly compressed, resulting in rising pressure and temperature-with discharge pressures reaching approximately 1.3 MPa. In oil-injected models, lubricating oil is injected during this process to provide cooling, sealing, and lubrication. When the compression chamber aligns with the discharge port, the compressed gas is expelled under pressure.
Each screw element features a fixed internal pressure ratio, determined by the screw length, pitch, and the shape of the discharge port. Rotor speed is optimized to a specific level to minimize mechanical and volumetric losses.
