The flange of the wind pressure sealing pipeline and the joint bearing on the sealing pipeline in the mill have poor sealing and air leakage, which reduces the wind pressure entering the grinding roll cavity;

When the mill is running or stopped, the unreasonable drawing of the wind in the mill will produce a slight negative pressure in the grinding roll cavity.

The above reasons may cause the air volume and air pressure to enter the ultrafine vertical mill cavity to decrease, and it is easy for micro-particle materials to enter the sealing air cavity of the ultrafine vertical mill, damaging the sealing ring and oil seal of the ultrafine vertical mill, and causing oil leakage or bearing damage to the ultrafine vertical mill.