Abstract: An in-service formulation for the removal of scale deposits from metallic working surfaces of boilers and for the ongoing prevention of build-up of such deposits on boiler surfaces, with such deposits commonly consisting of insoluble salts of calcium together with oxides of iron. The formulation comprises a blend of selected phosphonates, sodium lignosulfonate, one or more scale-modifying polymers, along with one or more chelants. Sodium gluconate is utilized for its ability to inhibit corrosion of ferrous surfaces. The pH of the working solution is adjusted to a level of between about 10.5 to 12.5. The formulation of the present invention provides a significant capacity for the removal of scale while remaining fully compatible with the water present in the system during and after scale removal, and the materials remain effective with contaminants present in the boiler water following a substantial number of cycles of concentration.

Abstract: An in-service formulation for the removal of scale deposits from metallic working surfaces of cooling towers and for the ongoing prevention of build-up of such deposits on cooling tower surfaces, with such deposits commonly consisting of insoluble salts of calcium together with oxides of iron. The formulation comprises a blend of selected phosphonates, one or more scale-modifying polymers, along with one or more chelants. Sodium gluconate is utilized for its ability to inhibit corrosion of ferrous surfaces as well as its synergistic effect in conjunction with other constituents for the removal of scale components (as demonstrated in U.S. Pat. No. 4,279,768). In those systems having non-ferrous metallic surfaces, such surfaces have been found to be adequately protected by the formulation through the incorporation of a triazole inhibitor.