REPAIR OF HEAT TRANSFER TUBE

PURPOSE:To ensure liquid-tightness by a method wherein a sleeve for repair, which is provided with an annular protrusion whose length is longer than a broken place, is inserted to the position of breakage, the heat transfer tube is heated to expand the diameter thereof to inflate the diameter of the annular protrusion of the sleeve for repair and, thereafter, the heat transfer tube is cooled to contract it. CONSTITUTION:The sleeve 21 for repair, inserted into the heat transfer tube 14 to a position corresponding to the broken place 17, is provided with a length sufficient to cover the broken place 17 and annular protrusions 22, 22 are protruded on the outer peripheral surfaces of both ends thereof while pipe expanding jigs 23, 23 are inserted to the positions corresponding to these protrusions 22, 22 respectively. Electrodes 24, 24 are inserted to both sides of the sleeve 21 for repair respectively. The electrodes 24, 24 are connected to an electric source 25 and electric current is flowed through the heat transfer tube 14 to heat and expand the diameter thereof. subsequently, the pipe expanding jigs 23, 23 are operated to inflate the annular protrusions 22, 22 and form bulge deformations 26, 26. Next, heating of the heat transfer tube 14 is stopped to cool and contract it. According to this method, the heat transfer tube is adhered to the sleeve strongly by the thermal contraction thereof and the annular protrusions bite into the inner surface of the heat transfer tube whereby the liquid-tightness may be ensured and the reliability of the tube may be improved.