METHOD FOR SECURING TUBES IN TUBE PLATES Russian patent published in 2000 - IPC

FIELD: plastic metal working, namely processes for securing tubes to tube plates of heat exchanging apparatuses due to using effect of localized directed plastic deforming of tube material. SUBSTANCE: method comprises steps of making annular trapezoidal cross section protrusions on outer surface of tube ends with diameter of protrusions equal to outer diameter of tube. In order to realize it, tube ends are preliminarily reduced, then deforming effort is applied to tube for providing yielding of tube material in direction different from direction of applied deforming effort. Tube is placed in opening of tube plate having annular rectangular cross section grooves; protrusions of tube are coincided with annular grooves of plates and then tube is fixed against possible motion. At fixing annular protrusions of tube are transformed to annular stepped cross section protrusions due to making annular recesses along perimeter of edges of annular grooves of plate. Diameter of said annular recesses is no more than 1.02 of diameter of opening of tube plate, width of said recesses is no more than 16,7% of width of annular groove. EFFECT: enhanced quality of tube and plate joints. 8 dwg