摘要 |
<p>Of the Disclosure Method, arrangement and sacrificial anodes for cathodic protection systems wherein inner portions of a tank or container, at least partially filled with a liquid, are exposed to a corrosive inner environment and are protected against the corrosion by the provision of a consumable sacrificial anode, the material of which gradually migrates through the liquid to and is deposited on the inner tank portions, without an external voltage being applied, and wherein the inner tank environment also promotes detrition of the sacrificial anode. The invention provides the anode with an inner metal tube, with openings in the tube wall, preferably by perforation, so that the anode material normally constitutes a barrier between the tube interior and the tank environment, and obtains an indication of progressive detrition or consumption of the anode, at which point the consumable anode should be replaced for continued effective cathodic protection. A pressure difference is usually effected between the tank environment and the tube interior, either by pressurizing the tank, or by providing a source of pressure or vacuum in the system. Indication may be obtained in several ways, e.g. in an inspection chamber having a window that allows the level of the entrained liquid to be inspected, in that the chamber may have a pressure-responsive member therein, such as a membrane, or a float that can actuate electrical or other switch means. The invention describes additional, optional features of the method, arrangement and sacrificial anodes. In a preferred, exemplary form, the latter may have a small slidable plunger that can give visual, preferably color-coded information on the consumption of the anode.</p> |