Maintenance-free self-sealing sleeve compensator

The utility model relates to the technical field of compensators, in particular to a maintenance-free self-sealing sleeve compensator which comprises a core pipe and a shell pipe arranged at one end of the core pipe in a sleeved mode, an anti-pull-off baffle ring is fixed to the end, close to the shell pipe, of the core pipe, and the core pipe and the anti-pull-off baffle ring are integrally formed through a thick-wall pipe. An anti-pull-off piston is arranged on one side of the anti-pull-off baffle ring, and the core tube is sleeved with the anti-pull-off piston; a filling cavity of an annular structure is formed in the inner wall of the shell pipe, the filling cavity is filled with flexible graphite, and a plurality of filling nozzles are installed on the outer wall of the shell pipe. The anti-pulling-off structure is composed of the anti-pulling-off baffle ring and the anti-pulling-off piston at the tail end of the core pipe, the anti-pulling-off baffle ring and the core pipe are integrated, the anti-pulli