The three-blade Roots blower is a double-impeller synchronous compression machine. Each three-blade rotor is supported by two bearings and uses a pair of synchronization gears to keep the relative position of the two rotors constant.

1. The three-blade Roots blower is a double-rotor compression machine. The axes of the two rotors are parallel to each other. They are driven by the prime mover through a pair of synchronous gears and rotate at a constant speed in opposite directions. The Roots blower is a volumetric fan, and the air volume delivered is proportional to the number of revolutions. Each rotation of the three-bladed impeller is performed by two impellers for three suction and exhaust times. Driven by the synchronizing gear, the wind is transported from the fan inlet to the discharge side along the inner wall of the housing.

2. Pre-intake principle The pre-intake compression method is mainly proposed to improve the backflow impact characteristics of the fan. In the process of the elementary volume (enclosed space surrounded by the impeller, casing and wall panel) moving from the air inlet to the exhaust port, high-pressure gas is introduced into it in advance through the air guide hole opened in the casing or wall panel, so that before the elementary volume is connected to the exhaust port, the internal pressure gradually reaches or approaches balance with the pressure of the exhaust port