| 摘要 |
A full double wall tank, primarily for underground fluid storage, which is simpler and more economical to construct than conventional full double wall tanks. An inner tank shell, preferably of steel, provides primary fluid containment and is the principal structural basis of the tank. An intermediate barrier layer is applied over the inner shell to define secondary containment space, and provides a base for application of a resin outer secondary containment tank shell which is preferably fiber-reinforced. Monitor sensor means is provided having access to the secondary containment space, preferably proximate the bottom of the tank. The barrier layer is preferably such as to provide a minimum of fluid-receiving secondary containment space for rapid and highly sensitive monitoring, and to provide cathodic protection for a steel inner tank shell. A presently preferred barrier layer of metallic foil which has a higher electrode potential on the electromotive force series of elements than iron, such as aluminum foil, serves these functions. Alternatively, a generally inert, flowable medium, such as silicone oil, containing a substantially uniform suspension of metal having such higher electrode potential will also serve these functions. In the preferred form of the invention, one or more vertical, diametrical monitor pipe struts extend down through the cylindrical body of the tank providing monitoring access to the secondary containment space proximate the bottom of the tank, while at the same time adding greatly to the beam stiffness of the tank.
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