Sealing device for rotating shafts, in particular stern tube sealing for ship propeller shafts

摘要

PURPOSE: To prevent a spare pacing from failure, when leakage is generated at a single piece of pressurizer. CONSTITUTION: A bushing 4a is installed on a propeller shaft 4. Support mechanisms 5, 5a, 5b fixed to an outer plate 2 are provided with a main packing 6 and a spare packing 8. The spare packing serves as an emergency packing, when the main packing goes in failure and has a flexible packing 14 and a packing holder 13 movable in the axial direction in a guide body 11 coupled with a support structure. A plurality of cylindrical recesses 13b are formed on a ring-shaped flange 13a of the packing holder at constant spacings. The guide body 11 is equipped with a piston 11b in the mating recess 13b, and the piston 11b is coupled with the recess 13b, so as to form a piston-cylinder unit. A branch pipe 17a to lead a pressure medium is connected with each piston- cylinder unit.