Closing cap with spring valve - has spring fixed to cap centre and valve plate relieving internal pressure

摘要

The cap has automatic valves opening against spring action to counteract pressure or vacuum inside the vessel concerned, these valves forming seals once these have been corrected. In the centre of the cap (1) is a pressure spring (4) having a high degree of torsional and lateral stiffness and solidly fixed to it at one end. At the other end is a larger valve plate (8), fixed directly to the lowermost spring coil (6), and correcting any internal pressure. A pot-shaped indentation (7) can be formed in the centre of the cap by pressing from outside, fitting inside the uppermost spring coil, its lowest edge being folded outwards to grip the coil. The centre of the indentation is pressed back in the opposite direction to form a stiffening dome and radially outwards against the indentation wall.