Roots blower, English Roots blower, rotary blower system belongs volume, with two-lobed rotor relative movement within the cylinder to compress and transport gas rotary compressor. This simple blower structure, convenient, suitable for low pressure gas delivery and pressurized situations, also be used as a vacuum pump. Roots blower system belongs volume rotary blowers. This compressor rotor shaft by synchronized gears remain engaged so that the two rotors. The rotor and the cylinder inner wall surface of each concave portion of the working volume of the composition, during the rotation of the rotor away from the gas suction port, when moved to the vicinity of the exhaust port and an exhaust port communicating instantaneously, due to higher pressure gas reflux, then the pressure in the working volume suddenly increased, then the gas is supplied to the exhaust passage. Two rotors do not touch, the gap between them, tightly controlled by a seal, so the exhaust gas from oil pollution. Shandong three cattle Machinery Co., Ltd.