280,918. Luth & RosÚns Elektriska. Aktiebolag, (Assignees of Lindstr÷m, A. F. H., and Segerstr÷m, C. D.). Nov. 19, 1926, [Convention date]. Radiators.-To in crease the heating surface of a sheet metal radiator, th( two side plates 4, 6 are extended at 13 14, and strips oi metal 15 may also be welded between the two, plates at their joints.