Abstract: A method for forming cooling coils of successive layers of rectangular configuration, in which the front end of an elongated tube is threaded between rolls of a straightening apparatus and clamped onto the periphery of a rectangular table, whereafter the table is rotated about a central axis while the incoming tube shifted in direction of this axis, and while the tube upstream of the table is held in taught condition by the straightening apparatus so that the tube is wound into a coil of rectangular configuration about the table. After a coil of predetermined length has thus been wound, the table is stopped, the tube cut between the straightening apparatus and the table and the cut rear end of the tube is also clamped to the table.

Abstract: An apparatus for manufacturing elongated curved tubular elements sequentially clamps longitudinally spaced end portions of a straight elongated tubular section, confines a central portion of the tubular section intermediate the clamped end portions between two dies, applies forces to at least one of the dies to displace the same and thus also the central portion of the tubular section in a predetermined direction and to a given extent with respect to the clamped end portions so that substantially S-shaped transitory portions of deformed cross-sectional shapes develop between the clamped end portions and the central portion of the tubular section, and restores the cross-sectional shapes of the transitory portions preparatory to sequential retraction of the dies and unclamping of the end portions of the tubular section by means of at least one mandrel which is introducible into the tubular section through at least one of the end portions thereof for passage into and through at least one of the transitory portio

Abstract: A method for forming cooling coils of successive layers of rectangular configuration, in which the front end of an elongated tube is threaded between rolls of a straightening apparatus and clamped onto the periphery of a rectangular table, whereafter the table is rotated about a central axis while the incoming tube shifted in direction of this axis, and while the tube upstream of the table is held in taught condition by the straightening apparatus so that the tube is wound into a coil of rectangular configuraton about the table. After a coil of predetermined length has thus been wound, the table is stopped, the tube cut between the straightening apparatus and the table and the cut rear end of the tube is also clamped to the table.