Cap having a chamber for a raw material and sealing mechanism for a vessel

摘要

A cap (1) has a plastic plug portion (4) and a plastic seal plug (5). The plug portion has a top wall (11) to cover an opening portion (3) of a vessel (2), a side wall (12) projecting from the top wall along an axis (X) of the plug portion, which wall has an inner circumferential surface arranged to fit on an outer circumferential surface of the opening portion, and a cylindrical wall (15) forming a receiving chamber (14) having an opening (13) at its lower end face, which wall projects from the top wall on the inside of the side wall. The seal plug has the outer diameter (D1) being larger than outer diameter (D2) of the cylindrical wall and is welded to the lower end face of the cylindrical wall while the receiving chamber is filled with a filling (16). In a sealing mechanism relating to the present invention, the seal plug closes the opening by being fixed to the cylindrical wall being loosely fitted into a sleeve (6). The sleeve is welded to the inner circumferential surface of the opening portion.