Abstract: The invention disclosed relates to an apparatus for permitting uninterrupted relief of cargo tank compartment internal pressures while also preventing the leakage of lading from the cargo tank to the surrounding atmosphere during sudden increases in the cargo tank internal pressure. According to one embodiment of the present invention, the cargo tank compartment pressure relief valve comprises a flow chamber coupled to an opening in the cargo tank compartment wall, wherein the flow chamber has a first opening in flow communication with the tank compartment and a second opening in flow communication with the atmosphere, whereby the first opening is under the control of a downwardly biased first vent head and the second opening is under the control of a downwardly biased second vent head.

Abstract: The invention disclosed relates to an apparatus for purging hazardous or volatile materials from external loading lines fixed to the bottom of cargo tank compartments. According to the invention, pressurized gas is directed into each external loading line to force the material to the lowest point in the loading line, through a purging tube, and back into the cargo tank compartment. In one embodiment, the purging apparatus is wholly contained on the cargo tank. In another embodiment, the apparatus is partly contained on the cargo loading facility and partly contained on the cargo tank.

Abstract: The invention disclosed relates to a method for purging hazardous or volatile materials from external loading lines fixed to the bottom of cargo tank compartments. According to the invention, pressurized gas is directed into each external loading line to force the material to the lowest point in the loading line, through a purging tube, and back into the cargo tank compartment. In one embodiment, the purging apparatus is wholly contained on the cargo tank. In another embodiment, the apparatus is partly contained on the cargo loading facility and partly contained on the cargo tank.