PROCESS FOR SHAPING MULTISTART CONCAVE-CONVEX SURFACE OF HEAT EXCHANGE TUBES Russian patent published in 2002 - IPC

FIELD: plastic metal working, namely manufacture of tubular products with helical profile for different purpose heat exchange apparatuses. SUBSTANCE: process comprises steps of rolling tubular blank at axially feeding it between freely rotating disc-shaped spinning rollers mounted with inclination angle α relative to lengthwise axis of blank; additionally forming on shaped convex helical surfaces multistart intermittent helical surfaces with profile depth consisting 0.3-0.5 of profile depth of multistart concave-convex helical surface; in order to realize it, passing tubular blank through additional disc-shaped spinning rollers arranged by angle β = 90^°-α relative to lengthwise axis of blank in rotary holder with possibility of rotation in direction opposite to that for tubular blank. It is possible to shape tubular blank with helix pitch different from that of multistart helical concave- convex surface or with different pitch values of helix along tubular blank due to cyclic change of revolution number of rotary holder. Such technique allows to enhance heat engineering parameters of heat exchangers due to spread surface of tubes providing increased heat transfer factor in condition of high intensity of turbulence agitation of heat transfer agent. EFFECT: improved design, enhanced heat transfer factor. 3 cl, 4 dwg