The Roots pump is essentially the same as a cam pump, but the rotor is Roots type. It can deliver liquids with viscosities of tens of thousands of centipoises. Roots pump is mainly two opposite rotation of the rotor is located in the pump body, driven by a pair of synchronous gear. Rotor and cam pumps, both bifurcated, but also clover and leafy. There are many shapes. Rotors of Roots pumps are intermeshing within the pump body but with play. The size of the gap depends mainly on the liquid viscosity. Over a certain viscosity range must be adjusted to increase the gap. Working principle of double lobe Roots pump and clover Roots pump. The principle is similar to a gear pump. When the rotor rotates, the liquid drains from the suction chamber to the discharge chamber along the casing wall of the pump body in a space formed with the pump body. When the shaft rotates one week, double leaf Roots pump suction, row two times, and clover Roots pump suction, row three times.