METHOD FOR SECURING OF PINS IN TUBULAR COILS OF HEAT-EXCHANGER UNIT Russian patent published in 2003 - IPC

FIELD: plastic working of metals. SUBSTANCE: method involves manufacturing pins with profiled ends; inserting pins into tubular coil openings provided with outer and inner annular channels made in the vicinity of opening ends in the form of outer and inner concentric depressions; filling annular depressions with shape memory material; fixing pins from any displacement and securing in tubular coil openings by applying force of die to inner surface of pin ends; profiling pin ends so as to form supporting portion and portion to be loaded, as well as intermediate conical adapter portion; forming supporting conical portion with outer diameter selected on condition that supporting portion be arranged at minimal gap with respect to inner annular depression; forming portion to be loaded with outer diameter smaller than diameter of tube opening; positioning pin in tubular coil opening so that supporting portion of each profiled end is located in inner annular depression of related opening; preliminarily fixing pins on annular depression edges made of shape memory material with following securing of pins in tubular coil openings. Method is used for manufacture of U- shaped heat-exchange units with the use of effect of localized directed plastic deformation of pin material. EFFECT: provision for obtaining non-detachable coupling of pins to tubular coils with contact pressures increasing in the process of operation of heat-exchanger unit. 5 dwg