Plug which closes a pressure vessel opening in a gas-tight fashion and has a drive shaft led through the plug and a gas-tight shaft bushing

摘要

The invention relates to a plug which closes a pressure vessel opening in a gas-tight fashion and has a drive shaft led through the plug and a gas-tight shaft bushing which is mounted on the plug. In order to be able to dismantle the shaft bushing without having to lower the pressure in the pressure vessel (for example, a reactor vessel), the drive shaft is constructed in two parts and there is arranged around the lower shaft part a stoppage seal which can be brought into the sealing position by an actuating tool and into the relief position by spring force. The actuating tool acts via a forcing screw on a tiltable disc which is situated on the lower shaft part and, for its part, compresses via a pressure plate a plurality of seal holders arranged on the shaft, as a result of which the seals are pressed against the shaft.