METHOD OF CLEANING METAL SURFACES FROM DEPOSITS Russian patent published in 2001 - IPC

FIELD: cleaning external and internal surfaces of hollow parts, for example, units and parts of engines from deposits. SUBSTANCE: method includes two- stage treatment of surfaces: at first stage, part is kept in aqueous solution containing 0.25 to 0.50 mole/g of H₂SO₄ and 0.05 to 0.1 mole/g of Na₂SO₃; at second stage, part is subjected to ultrasonic treatment through heating in aqueous solution containing 10 to 20 g/l of NaOH, 2.5 to 5.0 g/l of surfactants and 2 to g/l of hydroxy ethylidene diphosphonic acid. EFFECT: enhanced efficiency of cleaning external surfaces; reduction of time required for cleaning internal surfaces. 6 cl, 1 ex