METHOD OF CLEANING OUTER SURFACE OF HEAT TRANSFER TUBE

PURPOSE:To heat a heat transfer tube and scales thereby to crack and exfoliate scales out of the outer surface of the title heat transfer tube based on a difference in thermal expansion coefficient between both the heat transfer tube and scales by stopping the feed of cold water to the outside of the heat transfer tube and flowing a fluid heated within the tube. CONSTITUTION:With respect to a heat transfer tube 1 to which scales 3 are attached a fluid (c) heated to a temperature of 45 deg.C or more is caused to flow or stay within the heat transfer tube 1 in a state wherein cold water (b) is not caused to flow outside the tube 1 to heat the same tube 1 itself. When the heat transfer tube 1 is heated from its inner part without cooling the outside thereof, the scales 3 attached to the outer surface 2 are gradually dried, and cracks are produced in the dried scales 3 themselves depending on the difference in the thermal expansion coefficients, and at least almost all scales 3 are naturally exfolidated depending on the physical properties and environmental condition and the like of a material constituting respective parts.