| 摘要 |
<p>938,471. Anodes for preventing corrosion; indicating liquid levels. CATHODIC CORROSION CONTROL Ltd. Oct. 14, 1959 [July 14, 1958], No. 22563/58. Class 123 (1). A power-impressed cathodic control system for giving continuous internal protection to metal containers such as the tanks of oil tankers against electrolytic corrosion comprises a number of lead alloy anodes one of which is indicated at 5 each anode being mounted within a tank 3, containing e.g. seawater ballast 3, at the end of a liquid-tight support 7 passing through apertures in, and secured to, the roof 1 of the tank. A direct current source of electric power is connected to a contactor 13 the negative pole leading through a line 14 to the roof 1 and the positive pole being connected by a line 15 to the anodes 5 within a fluid-tight housing 8 secured to the roof 1. An auxiliary anode 9 is supported adjacent the upper end of the roof by an insulator 10 so that, when the seawater rises to a level 4, the anode 9 is immersed to produce a galvanic current which flows from the auxiliary anode 9 through lines 17, 18 and a relay 16 to the tank and the seawater electrolyte. Operation of the relay 16 actuates a slave relay 19 which influences the contactor 13 so that power is supplied to the anodes 5. Apparatus 21 may be provided in the auxiliary anode circuit to operate an indicator when galvanic current flows. Similar apparatus 22 may be incorporated in the circuit of the auxiliary anode 22 to indicate when the anodes 5 are energized. The indicator in the auxiliary anode circuit may be used to control the pumping apparatus for filling the tank. In a modification elongated cable-type lead alloy anodes are employed each anode being supported by electrically insulating members from a wall of the tank and the end of the anode being passed through the roof 1 with its upper end coated with an insulating sheath. The end of the anode below the normal level of the water is sealed off. In a further modification each anode comprises a freely suspended loop supported at each end from the roof 1. Specifications 880,519 and 911,775 are referred to.</p> |
