Roots blower has many advantages. Under normal circumstances, the change of pressure has little effect on the air volume, and the speed of Roots blower is proportional to the speed. Therefore, roots blower basically belongs to constant volume; there is no pulsation during suction and exhaust, and there is no need to buffer air tank; the floor area is small, which is convenient for layout and installation; 0.2-0.5mm is reserved between rotor and handle, rotor and shell The air flow is allowed to contain certain dust; Compared with the hydraulic jet pump and water ring vacuum pump, there is no problem of "exhaust with water", reliable operation, convenient maintenance and durable.