Heat exchange tube repairs.

摘要

in a method of repairing a defective tube (2) in a tube-in-shell heat exchanger by inserting a tubular repair sleeve (1) within the defective tube (2) and sealingly bonding one end region of the sleeve to the tube (2) and the other end region of the sleeve to the tube sheet (4) in a manner such that the defect (for example a defective tube/tube sheet weld (3)) is bridged, the improvement of providing a support (7) against which the said one end of the sleeve can be explosively welded to the tube. The support (7) comprises a mass of low melting point alloy cast around the tubes so as to provide support at the welding level for the defective tube (2) as well as surrounding tubes. The support (7) is removed after welding by remelting the alloy and causing the liquid alloy to run away. Inserts (8) of high melting point metal can be included in the mass as reinforcement, and the casting can be effected in a removable box (6) fo which the tube sheet (4) forms the base, the walls surrounding at least a part of the tube array which includes the defective tube (2). Examples of suitable alloys are given.