Abstract: Structure mounted at the top edge of an open top tank having a floating roof covering the fluid contents. It is an airfoil that extends above the edge, and directs air flow due to wind, down onto the windward side of the roof to equalize the otherwise uneven pressure caused by wind that increases the undesirable vapor emissions from the contents of the tank and could tend to tip the roof.

Abstract: A hydrocarbon vapor control system for preventing escape to the atmosphere, and for disposing of such vapors by clean burning. It includes a pair of adsorption beds and means for alternatively connecting them to receive the vapor while the other one of the beds is being regenerated with the effluent vapor from the regeneration being burned. There is a hydrocarbon detector at the outlet of each adsorption bed to determine when it has become saturated.A hydrocarbon vapor control unit includes a canister with an inlet at the bottom to admit the vapor. There is a support for an adsorption bed in the canister, and there is an outlet at the top which is designed to permit burning the effluent when the adsorption bed is being regenerated by air flow through the inlet.