Vapour recovery systems in a storage tank filling pipe

In a tank installation for a volatile liquid and having a tank with an ullage space above liquid in the tank wherein vapour from the liquid collects, said tank installation having a fill-pipe for the introduction of volatile liquid into the tank, said fill-pipe having an exit which is normally within the liquid in the tank, and a vapour recovery system for use during filling of the tank to recover vapour displaced from said ullage space as the volume of liquid in the tank increases, there being a region of reduced cross-sectional area provided within the fill pipe, a method of recovering vapour comprising:

• generating a reduced static pressure within the region of reduced cross-sectional area by the in-flow of liquid along the fill-pipe;
• drawing the vapour along a duct entering the fill-pipe so as to communicate between the ullage space and the region of reduced cross-sectional area, by virtue of the reduced static pressure at said region;
• and
• normally closing-off said communication of the ullage space with the region of reduced cross-sectional area by a normally-closed valve assembly associated with the duct, which valve assembly is opened by the in-flow of liquid along the fill-pipe into the tank during the filling thereof, such that the reduced static pressure in the region of reduced cross-sectional area during filling of the tank draws vapour from the ullage space in the tank into the opened duct to be entrained in the in-flowing liquid.