Abstract: A method and apparatus for securing one or more parts, each of which is provided with an opening, to a hollow member. In the starting state, the inner diameter of the opening of the parts is greater than the outer diameter of the surface provided on the hollow member for securing the part. The parts are placed in the prescribed position on the hollow member prior to the securing operation. In order in a simple and economical manner to reliably secure the parts to the hollow member without the danger of overstressing the latter, and without the danger that the parts will loosen, a temperature difference is produced, prior to placing the parts on the hollow member, by heating the parts and/or by cooling the hollow member. Subsequently, each part is secured to the hollow member by widening the latter at least in the securing regions thereof, and by a subsequent shrink fitting of the parts onto the hollow member as a consequence of the temperature equalization that occurs.

Abstract: An apparatus for securing straight tubes between two tube sheets in a pressure-tight manner, especially in the manufacture of heat exchangers. Tubes are inserted, with play, in bores of the tube sheets. One end of each tube is hydraulically expanded via a pressure medium to thereby press this one end against the associated tube sheet. The one end is secured to the associated tube sheet, preferably by being welded thereto. Each tube is heated in conformity with a prescribed prestress that is to be produced in secured ones of the tube to take into account subsequent operation conditions to push a portion of the non-secured other end of the tube out of its associated tube sheet until a predetermined difference in length between the cold and heated-up states of the tube is pushed out.

Abstract: A method and apparatus for securing straight tubes between two tube sheets in a pressure-tight manner, especially in the manufacture of heat exchangers. Tubes are inserted, with play, in bores of the tube sheets. One end of each tube is hydraulically expanded via a pressure medium to thereby press this one end against the associated tube sheet. The one end is secured to the associated tube sheet, preferably by being welded thereto. Each tube is heated in conformity with a prescribed prestress that is to be produced in secured ones of the tube to take into account subsequent operating conditions to push a portion of the non-secured other end of the tube out of its associated tube sheet until a predetermined difference in length between the cold and heated-up states of the tube is pushed out.

Abstract: A method of securing tubes between tube sheets of a heat exchanger, with the tube sheets being interconnected via a housing. The tubes and/or the tube sheets of are made of a steel that has to be annealed after a welding process. To be able to provide a stress-free connection between the tubes and the tube sheets, and to enable simple repair of the tubes, the length of at least one end of each tube is extended by welding thereto a tubular piece that is made of a material that can be welded without subsequent thermal treatment being required. Sleeves that extend the length of the holes in the tube sheet are welded onto the outer surface of at least one of the tube sheets. At least the free end of each sleeve is made of a material that can be welded without subsequent thermal treatment being required. One end of each tube, if such end is not provided with a tubular extension, is welded onto a tube sheet.

Abstract: An apparatus for the expansion of tube ends inside of a tube plate by means of a probe insertable in the respective tube ends, the probe forming an annular space with the tube member to be widened by means of two seals spaced from one another, a pump operatively feeding the annular space with a pressure medium for the expansion, and a pressure intensifier for bringing the pressure medium to a required pressure. A medium separator is connected via a back-pressure valve to a secondary-sided space of a primary-sided hydraulic oil driven pressure intensifier. A piston displaceably disposed in the medium separator is biased by a return spring in the medium separator, and the pump feeds the hydraulic oil displacing the piston against the restoring force of the return spring for the filling of the secondary space of the pressure intensifier with an operating medium. The operating medium flows from an operating medium-supply container and another back-pressure valve to the secondary side of the medium separator.

Abstract: A method of hermetically swaging tubes into the bores of heavy heat exchanger tube plates, by first expansion-swaging the inserted tube end portion under a very high hydraulic pressure and by then roll-swaging a portion of the expansion-swaged length portion, in order to replace the expansion-related tensile stress in the tubes with a compressive prestress, and in order to eliminate annular crevices at the inner edges of the tube plate bores.

Abstract: A device and method for the expansion-swaging of tubes into a tube plate where an expansion core is inserted into the tube and two pressure rings on the core axially delimit a radially very narrow pressure space into which a very highly pressurized fluid is introduced, thereby expanding the tube. The pressure rings are of highly pressure resistant material and are supported by abutment shoulders of inner and outer core guide portions engaging the tube with minimal clearance.