Freezeproof breather valve

A pressure relief valve comprising a pallet seat adapted to be mounted in alignment with a vent opening communicating with the interior of a tank, said seat being positioned along a substantially horizontal plane, a pallet assembly movable substantially vertically between open and closed position with respect to the seat and having a Teflon seal member engageable with the seat in closed position, means for applying weight to the pallet assembly, said pallet assembly mounted relative the seat such that it moves upward to open position in response to the pressure within the tank exceeding atmospheric pressure by a given value, guide means for said pallet assembly to guide same between open and closed position so that the assembly properly seats in closed position, said guide means including a vertically extending guide rod mounted on said pallet assembly and extending above and below same, the outer ends of said rod having Teflon portions, a tubular guide member mounted for guidingly receiving the upper end of said rod and a Teflon guide ring for receiving the Teflon portion of the lower end of the rod, and a Teflon blowdown flange mounted along the periphery of the pallet assembly.

A combination pressure and vacuum relief valve for a tank comprising, a housing having a first opening for communicating with the interior of the tank, a second opening communicating with the atmosphere and having a pressure relief valve associated therewith, and a third opening communicating with the atmosphere and having a vacuum relief valve, said vacuum relief valve including a pallet seat mounted in alignment with said third opening, a pallet assembly movable between open and closed positions with respect to the seat and having a Teflon seal member engageable with the seat in closed position, hinge means for supporting said pallet assembly including coating Teflon members whereby said pallet assembly moves to closed position under gravitational force, and magnetic means applying a given force to said pallet assembly toward closed position.

A combination pressure and vacuum relief valve mounted on the top wall of a tank comprising, a housing having a first opening for communicating with the interior of the tank through the top wall thereof, a second opening communicating with the atmosphere and having a pressure relief valve associated therewith, and a third opening communicating with the atmosphere and having a vacuum relief valve, vent means for said pressure and vacuum relief valves covering said valves and connecting same to the atmosphere, said vent means including a vertical downwardly opening member extending down along the side of the tank at a level below the top wall thereof, and said valves having a plurality of movable and coating parts constructed of polytetrafluorethylene material that will prevent malfunction in the event ice collects on said parts.

A freezeproof breather valve for a crude oil storage tank for relieving above and below atmospheric pressure conditions therein, said breather valve being mounted on the top wall of the tank and comprising, an above atmospheric pressure relief valve portion, a below atmospheric pressure relief valve portion and a venting means for said valve portions having a downwardly facing opening arranged alongside of the tank at a level below the top of the tank such as to avoid being sealed by the buildup of ice and snow on the tank, said valve portions having movable components of polytetrafluorethylene material.