Vent valve

Claim 1

A vent valve apparatus for relieving interior fluid or vapor pressure from within a container for fluids by automatically releasing a portion of said fluid or vapors from said container, or relieving partial vacuum from within said container by automatically releasing air into said container, said apparatus including valve housing means restrainably affixed to said container; said valve housing means including an upper housing portion and a lower housing portion; said upper housing portion operably attached to said lower housing portion to describe a vent cavity; said vent cavity being in operable communication with the interior of said container to describe a vent conduit; check valve element means operably disposed within said vent conduit; said check valve element means operably disposed between a closed position sealing said vent conduit and an open position for releasing said portion of fluid or vapor through said vent conduit into said vent cavity, vent release apertures in said upper housing means in operable connection with said vent cavity for releasing said portion of fluid or vapor from said housing means to the atmosphere; said check valve element means being biased into its closed position by check valve biasing means; said check valve biasing means serving to maintain said check valve element in said closed position until overcome by a particular fluid or vapor pressure exerted against said check valve element means so as to move said check valve element to the open position; and one-way valve element means positioned in said apparatus to enable one-way passage of air from the atmosphere to the interior of said container, the improvement comprising: said one-way valve element operably affixed to the interior of said check valve element so as to prevent passage of liquid or vapor to the atmosphere from the interior of said container when said check valve element is in said closed position; said one-way valve element allowing communication between said container interior and the atmosphere whenever said interior container pressure falls below atmospheric pressure so as to alleviate the partial vacuum therein; said check valve element and said one-way valve element operating to automatically vent said container or allow passage of air into the interior of said container whether said apparatus is in a horizontal or vertical orientation; said upper housing portion comprising a top part and a bottom part, said top part having a thin-walled construction, said thin-walled top part being shaped so as to receive said check valve biasing means, and serving to break away from said container in response to the exertion of excessive force by said check valve element means and in turn said check valve biasing means thereon, so as to provide increased venting of said container interior; and said valve housing means comprising a plastic material such as high density polyethylene, to provide eventual melting of said housing means in the event of fire and thereby provide maximum venting of the contents of said container.