Fuse element with a temporary quasi-hermetic seal of its interior

摘要

A fuse element includes a fusible conductor which extends within a gas filled cavity in a cylindrical tube. The fuse element includes a cylindrical tube comprising, an electrical insulator between two end faces of the tube, two end caps of an electrically conductive material being applied to the two ends of the tube such that an electrical contact is produced with the fusible conductor. At least one respective sealing element is inserted in at least one of the two ends in a space between the cap base and the end face of the tube and/or into a portion of the cavity of the tube adjacent to the end face such that one or more pressure balancing passages remain between the gas filled cavity within the tube and the external surroundings of the fuse element. The one or more pressure balancing passages are of such small cross-section that changes in pressure in the cavity are balanced only very slowly. A sudden increase in pressure in the cavity, such as occurs as a result of an arc, which is produced when the fusible conductor ruptures, can act to quench the arc.