Labyrinth seals are widely used in the field of turbomachines with a great influence on the efficiency and economy issues. Aiming at the problem of a large number of stone leakage in the gas seal of medium speed coal mill HP1003 produced by Shanghai heavy machinery factory

this paper analyzes the reason of throwing out stone

confirms the cause of leakage of traditional gap seal

and changes the traditional gap seal into labyrinth seal to reduce the sealing gap. After the reform

the gas seal pressure of the coal mill is guaranteed

and reduceing the loss of air seal

avoiding the small pebbles entering the gas seal of the coal mill

eliminates the phenomenon of large amount of air leakage and stone leakage in the gas seal of HP coal mill

The annual cost saving is 166 252.8 yuan

and the maintenance time is shortened from 3 days to 0.5 days.