VAPOUR RECOVERY SYSTEMS IN A STORAGE TANK FILLING PIPE

摘要

A vapour recovery system for use during filling of a tank installation (10) with a volatile liquid. The tank has a fill-pipe (12) for the introduction of the liquid into the tank wherein the exit (19) to which fill-pipe is normally below the liquid level (17) in the tank. The vapour recovery system (21) comprises means defining a reduced cross-sectional area region of the fill-pipe and a duct extending from that region through the side wall of the fill-pipe (12) into the ullage space (16) above the liquid level in the tank. The system further comprises a valve assembly associated with the duct which valve assembly normally closes off the duct, but which valve is opened by flow of liquid along the fill-pipe into the tank, such that vapour in the tank may be drawn along the duct from the ullage space (16) by the reduced static pressure in the region of reduced cross-sectional area of the fill-pipe (12). The present invention also relates to a method of recovering vapour using such a system.