1) between the ring and static ring seals and wear is too large, the design load coefficient is unreasonable, make the seals to produce the phenomenon such as crack, deformation and breakage.

2) several auxiliary seal ring have defects or defects due to improper assembly, and select auxiliary seal ring is not suitable for working condition of the medium.

3) spring pre-tightening force not enough or after long time operation, fracture, corrosion, relaxation, coking, as well as the working medium of crystallization suspended particles or long time accumulation of congestion in spring clearance, cause spring failure, compensation seal ring can't float, leak;

4) due to the dynamic and static ring seals and shaft centerline verticality deviation is too big, make the seals bonding imprecise cause leakage;

5), because of the large shaft axial channeling momentum with seal related accessories or quality is bad, are prone to leakage phenomenon.