Cathodic protection of metal surfaces exposed to aqueous liquid

Claim 1

IN A METHOD OF CATHODIC PROTECTION FOR THE INTERIOR FERROUS METAL SURFACE OF A VESSEL, THE PROCEDURE WHICH INCLUDES FILLING THE VESSEL WITH WATER, AND WHICH COMPRISES THE STEPS OF: INCORPORATING INTO AND DISTRIBUTING IN SOLUTION THROUGHOUT SAID WATER, A SOLUBLE SALT, SELECTED FROM THE CLASS CONSISTING IF NITRATE AND CHLORIDE, OF A METAL SELECTED FROM THE CLASS CONSISTING OF ALKALINE EARTH METALS AND MAGNESIUM, SAID WATER BEING ESTABLISHED AND MAINTAINED AT A PH OF 5.0 TO 8.5, SAID ABOVE-DEFINED SALT BEING INTRODUCED IN AN AQUEOUS SOULTION THEREOF PREPARED PRIOR TO SAID INTRODUCTION, INCORPORATING INTO SAID DISTRIBUTING TO SOLUTION THROUGHOUT SAID WATER, AFTER THE AFORESAID INCORPORATION AND DISTRIBUTION OF THE ABOVE-DEFINED SALT, A SOULBLE BICARBONATE OF AN ALKALI METAL, SAID SOULBLE BICARBONATE BEING INTRODUCED IN AN AQUEOUS SOLUTION THEREOF PREPARED PRIOR TO SAID INTRODUCTION, THE PH OF THE WATER IN THE VESSEL BEING MAINTAINED IN THE AFORESAID RANGE AS AND AFTER SAID SOLUBLE BICARBONATE IS INTRODUCED, AND PASSING UNIDIRECTIONAL CURRENT THROUGH THE WATER FROM ANODE MEANS IN THE VESSEL TO SAID FERROUS METAL SURFACE TO PROVIDE CATHODIC PROTECTION FOR SAID SURFACE, THE AFORESAID SELECTED MATERIALS BEING ADDED TO THE WATER IN AMOUNTS EQUAL TO NOT MORE THAN ABOUT 2000 P.P.M., SAID SOLUBLE BICARBONATE REACTING IN THE WATER TO PRODUCT THE BICARBONATE OF THE AFORESAID MATAL SELECTED FROM THE CLASS CONSISTING OF ALKALINE EARTH METALS AND MAGNESIUM, SAID LAST-MENTIONED REACTION-PRODUCED BICARBONATE BEING THEREAFTER COVERTED AT THE CATHODICALLY PROTECTED SURFACE. WHILE SAID UNIDIRECTED CURRENT IS BEING PASSED, INTO A DEPOSIT OF THE CARBONATE OF SAID METAL SELECTED FROM THE CLASS CONSISTING OF ALKALINE EARTH METALS AND MAGNESIUM, AT SAID SURFACE, AND SAID FIRST-MENTIONED SALT AND SAID SOLUBLE BICARBONATE BEING INTRODUCED IN THE WATER IN AMOUNTS SUFFICIENT TO PROVIDE AT LEAST 50 P.P.M., OF SAID REACTION-PRODUCED BICARBONATE IN THE WATER.