Shaft seal is only used for open compressors, and fully enclosed or semi-enclosed compressors have no shaft seal. The shaft seal is prone to air leakage and oil leakage. The causes of shaft seal unsealing are: poor contact between the sealing surface of fixed ring and movable friction ring, aging of elastic ring (oil-resistant rubber ring) and insufficient elasticity of shaft seal spring. 1. Repair of fixed ring and movable friction ring The damage of friction ring is mainly caused by the galling of sealing surfaces of fixed ring (high lead bronze) and movable ring (ductile iron). Repair method: put the sealing ring on the cast iron plate or glass for fine grinding, and use 400# abrasive for fine grinding: grind the oilstone until it is smooth without scratches. If the wear is deep, new parts can be replaced, and the replaced new parts should be polished before use. The grinding method is the same as the valve plate. If the groove on the sealing surface of the friction ring is deep, it can be compensated by plating bearing alloy, and then repaired and ground. If it is difficult to grind or electroplate the bearing alloy, it can also be repaired by turning. If it cannot be repaired, it should be replaced with a new one. 2. When the elastic ring is aging, only new parts can be replaced. 3. If the elasticity of the spring is insufficient or deformed, the spring can be heat-treated again and corrected. Heat treatment process: annealing and shaping, and then quenching and tempering at medium temperature. Irreparable springs must be replaced with new ones.