Non-refillable bottle closure

In a bottle closure device, for sealably closing and preventing fraudulent filling of bottles fitted therewith, comprising:

• a valve body adapted to be inserted as a plug into the neck of a bottle;
• an annular flange at one end of said valve body, adapted to abut against the end face of the neck of said bottle;
• means defining an annular valve seat within said valve body;
• an inverted mushroom headed valve shutter located within said valve body, said valve shutter having:
• (i) a hollow tubular stem the axial cavity of which is open at the free end thereof, and
• (ii) an enlarged head for cooperation with said valve seat;
• a cap support fixed at one end to said valve body;
• and
• a cap, an externally threaded cylindrical portion of said cap support adapted for receiving a correspondingly threaded part of said cap, said cap having an axially extending central pin provided with longitudinal ribs, which pin engages into said axial cavity of said stem of said valve shutter when said cap is screwed onto said cap support, the improvement wherein,
• (a) said longitudinal ribs each have a sharp outer edge,
• (b) said axial cavity in said stem of said valve shutter has, an inner part adjacent said mushroom head of said valve shutter having a circular cross section, and
• (c) the size of said ribs on said pin of said cap being such that, when said cap is completely screwed onto said cap support, the radius of the circular section of said inner part of the axial cavity, at any point along the axis of said inner part, is less than the radial distance between said sharp outer edges and the axis of said pin of said cap at that point.