Shaft sealing includes sealing of three parts, namely, shaft extension, bearing seat end and shaft end, the combination of which is related to the structural type of wall plate. Among them, the role of the shaft end seal is mainly to prevent gas leakage, the other two parts in addition to preventing oil leakage, and sometimes there is a requirement to seal the gas. Usually, the device that seals the gas (or seals the gas as the main purpose of the work) is called a gas sealing device, and the one that simply seals its oil is called an oil sealing device.

Among the common sealing types of Roots fan, it is divided into open wall plate - common seal and closed wall plate - common seal. The sealing device of the open wall plate-ordinary seal is mainly the use of a skeleton oil seal in the shaft extension part, the use of an oil return groove in the rear part of the bearing housing, and a labyrinth seal, a rising ring seal, a packing seal and a skeleton oil seal group in the shaft end part. The main feature of open wall plate-ordinary seal is that the conveyed gas will not leak into the oil tank, but may leak into the atmosphere. Lubricating oil will not leak into the housing.

Enclosed wall panels - The main sealing devices of ordinary seals are skeleton seals for shaft extension parts, oil return grooves or skeleton oil seals for the rear part of bearing housings, and labyrinth seals for the shaft end parts. Enclosed wall panels - The main feature of ordinary seals is that the conveyed gas may leak into the oil tank or even to the atmosphere. When vacuum is drawn, oil may leak into the housing.