Spill condition venting system

Claim 1

In a double wall tank for the storage of low temperature fluids, including an inner wall defining an inner tank, an outer wall, and an annular space between the inner and outer walls of the tank substantially filled with granular insulating materials, a control system for controlling in the event of a spill into the annulus, flow of stored fluid into and out of said annulus and for controlling and directing vapors resulting therefrom including: at least one conduit located in the annulus and having an inlet fluidly connected to the inner tank at an overflow level of the inner tank and an outlet end located in and fluidly communicating with the annulus, said conduit controllably directing the spilled liquid down the tank and into the annulus at the bottom of the annulus; vapor channel defining means located in the annulus and having an inlet fluidly connected to an outlet of said conduit via the annulus, said vapor channel defining means defining at least one vapor channel for directing the vapor generated from the spilled liquid in the bottom of the annulus to the top of the annulus, said channel defining means including means filtering said vapor flowing in said vapor channel, and preventing flow of granular insulation into said vapor channel; vapor directing means located in said vapor channel for directing the flow of said vapors out of the annulus at the top thereof; and vapor venting means fluidly connected to said vapor directing means.