Stopper for flask under vacuum - has outside skirt fitting under flange in flask neck

摘要

The stopper (1) has an internal sleeve with a top flange (3) which rests on the top of the flask neck (B). The stopper has a domed end (7) and a central bore (11). The stopper has a skirt (2) with a flange (5) which can be reversed to hook under the flange (B) on the flask. The flask is evacuated through the tube (9) with a central bore (10). The tube is fitted with ribs (6) which form a Vee when the flask is under vacuum.