Pressure relief device for internally pressurized fluid container

A pressure relief device for a container having a cylindrical side wall, said container being of a type adapted to contain fluid under pressure, said device comprising:

• an inwardly protruding generally concave metal closure element circumferentially joined to one end of said side wall, an integrally formed outwardly protruding central area in said closure element, said central area being partially circumscribed by a weakened line of reduced material thickness, said closure element having a structural integrity which reacts to an overpressurization of the fluid in said container by undergoing eversion which intitiates a fracture of the closure element along said weakened line, thereby permitting the over-pressurized fluid contents of said container to escape through said fracture.

A pressure relief device for an internally pressurized fluid container of the type having a cylindrical side wall, said device comprising:

• an inwardly concave closure element circumferentially joined to one end of said side wall, said closure element having an annular outer area connected by an annular intermediate area to a central area, the said outer, intermediate and central areas respectively having progressively diminished resistance to outward eversion caused by overpressurization of the fluid contents of the container;
• and
• an outwardly convex tab member in said central area, said tab member being partially circumscribed by a line of reduced material thickness which fractures during eversion of said closure element.