| 摘要 |
<p>869,619. Preventing corrosion. MILLER, W. L., PREISER, H. S., and TUDOR, S. Sept. 3, 1958 [Nov. 19, 1957], No. 28325/58. Class 123(1) Large metal containers 1, e.g. tanks of cargo ships, are protected from corrosion by mounting sacrificial anodes 2, made e.g. of magnesium, zinc &c., in the bottom of the tank and coating all of the lower tank surfaces, at least to a distance of ten anode diameters from the anodes, with a dielectric insulating coating 6 which is resistant to liquids and electric currents and is made, e.g. of asphalt, portland cement with added silicate, or phenol-formaldehyde &c. The coating 6, preferably extending up the tank walls to a height, e.g. of 6 ft., depending upon the size of the tank, protects the tank bottom particularly when it is empty and causes an even distribution of galvanic currents, between the anodes and the unprotected metal parts of the order of about 10 m.a. per sq. ft. In a modification, Fig. 3, inert anodes 21, made, e.g. of high silicon iron and insulated from the tank 22, are connected to the positive pole of a battery 25 or other low voltage, D.C., electrical source, the negative pole of the battery being connected to the tank 22 the bottom of which is provided with an insulating coating 23. An anode 27 as shown is suspended within the tank 22 by means of a conductor 28 which is covered with an insulating material and is connected to the positive pole of the D.C. electrical source. If the anode is of the sacrificial type the conductor 28 is connected to the tank 22. The suspended anodes may be used alone or in conjunction with the anodes supported from the bottom of the tank.</p> |
