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

FIELD: plastic metal working, namely processes for securing tubes to tube plates of heat exchanger with use of effect of local directed plastic deforming of tube material. SUBSTANCE: method comprises steps of making annular protrusions on outer end portions of tubes; placing tube in tube opening having annular grooves; matching annular protrusions of tube with annular grooves of tube opening; fixing tube against its possible motion and securing tube to tube grate by flaring due to applying compression effort to inner surface of tube. Annular protrusions have rectangular cross section with base equal to width of groove and with height exceeding depth of groove. Annular grooves have cross section in the form of rectangular trapeziums whose acute angles are turned one to another. At joining inner annular sealings are formed between lateral surfaces of grooves and protrusions for providing tube tension between them. EFFECT: enhanced quality of tube joints. 3 dwg