Patent ID: 6886579

Claim:
A vent cap comprising: a main housing having a bottom surface, a concave top surface, an outer circumference and an interior portion; a cap cover having perforations there through, disposed upon the top surface of the main housing, so as to form a ball bearing containment chamber defined by the concave top surface and the cap cover; a chamber disposed within the interior portion of the main housing, said chamber having a upper surface and an outer circumference; a container attachment means provided adjacent the outer circumference of said chamber, opposite the upper surface thereof, one or more sealing spring mounts disposed within said chamber, adjacent the outer circumference thereof; a piston chamber disposed within said interior portion of said main housing, extending from the upper surface of said chamber to the top surface of said main housing; one or more gas release ducts disposed within said interior portion of said main housing, extending from the upper surface of said chamber to the top surface of said main housing; a piston having a head and a base, said head having a first end adjacent said base and a second proximal end, said piston being movably disposed within said piston chamber; a sealing spring disposed within said chamber having a first end and a second end, said first end being attached to one or more of said sealing spring mounts and the second end being attached to the base of said piston; a ball bearing rollably disposed within said ball bearing containment chamber; one or more burst disc gas release ducts, each of said burst disc gas release ducts having a first mouth disposed adjacent the outer circumference of said main housing, a second mouth disposed adjacent the outer circumference of said chamber, and a duct passage formed there between, and one or more burst discs removably and replaceably mounted in each of said gas release ducts.