Abstract:
The invention relates to a welding head for magnetic pulse welding of hollow thin-walled profile to an inner member having a complementary outer form to said hollow thin-walled profile. The weld head comprises two movable weld head halves (10a,10b) forming said weld head wherein each half has at least one individual induction coil (12a,12b) connected to a power source independently from the other weld head half, with coils wound in a kidney-shape. The work piece is clamped between shapers(15a,15b) integrated with each half. With this weld head could for example work pieces such as tubular thin-walled profiles be welded, even if they are integrated in a closed tubular design, as the weld head could be closed quickly over the welding position and opened for release of the work piece without experiencing arching in clamping area.
Abstract:
A method of brazing a plate heat exchanger comprising a stack of heat exchanger plates (110,115) is provided with a pressed pattern of ridges (R) and grooves (G) adapted to form contact points between the plates (110, 115) and provide for interplate flow channels for media to exchange heat is provided. The interplate flow channels are in selective fluid communications with port openings (120, 130, 140, 150) provided near comers of the heat exchanger plates (110, 115). The method comprises the steps of calculating or measuring the exact position of all contact points between the ridges (R) and grooves (G) of the neighboring plates (110, 115), applying brazing material (B) close to, but not at, the contact points, stacking heat exchanger plates (110, 115) provided with brazing material to a stack,placing the stack of heat exchanger plates (110, 115) in a furnace, heating the stack of heat exchanger plates (110, 115) to a temperature sufficient for melting the brazing material (B), andallowing the stack of heat exchanger plates (110, 115) to cool down such that the brazing material (B) solidifies and binds the plates (110, 115) together.
Abstract:
A process that uses friction stir welding to connect a tube, for example a thin gauge tube having a wall thickness of about 2.54 mm (0.100 inch) or less, to another element, such as a tube sheet of a heat exchanger. The process employs a tubular anvil that is installed into the end of the tube and which, in one embodiment, can provide material during the friction stir welding process. After the weld is complete, the weld zone between the tubular anvil and the tube is machined away and the anvil tube removed.
Abstract:
The present application relates to a method of manufacturing a tube sheet (7) and heat exchanger assembly for a pool reactor or pool condenser for use in the production of urea from ammonia and carbon dioxide, wherein the method comprises manufacturing of the tube sheet (7) from a carbon steel material grade and providing said tube sheet (7) with corrosion protective layers (8, 9) of an austenitic- ferritic duplex stainless steel grade, wherein the heat exchanger comprises at least one U-shaped tube (13) of an austenitic-ferritic duplex stainless steel grade, the method further comprises inserting at least two sleeves (11) of an austenitic-ferritic duplex stainless steel grade through the tube sheet (7) such that both ends of the sleeve (11) extend in a direction away from the tube sheet (7), the method further comprises connecting the sleeves (11), at least the opposing ends thereof, to at least the protective layers (8,9) of the tube sheet (7) and finally, connecting both ends of the at least one U-shaped tube (13) to the respective sleeves (11).