Abstract: Crystallized salt builds up in heat transfer tube so quickly that its thickness can increase to several mm within 1 h.Frequent pauses for washing have strong impact on efficiency.So,the automated cleaning technique by using self-rotating flat belt to remove deposits was researched.A simulated experiment scheme was designed as follows:A stainless steel tube( 38 mm×3 mm×1 800 mm) filled with hot NH<SUB>4</SUB>Cl saturated solution,was surrounded by a carbonized steel sleeve,which was applied with countercurrent cooling water.A plastic elliptical skew gear flat belt was then installed inside the heat transfer tube.The measurement of heat transfer coefficient and thickness of scaling layer was compared before and after the installation of self-rotating flat belt inside the heat exchange tubes.The results showed that: a long-term continuous production could be realized after the installation of self-rotating flat belt,and heat transfer efficiency increased by about 63% than 8 h cyclical pause for washing;the thickness of the crystal salt dropped from 5.4 mm to 2 mm below;the self-rotating flat belt will not damage the protection film of the inner wall and not to wear the inner wall of the tube either.<BR>