Manufacture of heat exchange tubing

Claim 1

THE METHOD OF MAKING AN EXTENDED SURFACE HEAT EXCHANGE UNIT COMPRISING THE STEPS OF PROVIDING A LENGTH OF TUBING AND A LONGITUDINAL STRIP OF SHEET STOCK, SLITTING SAID STRIP OF SHEET STOCK INWARDLY FROM ITS OPPOSITE SIDES TOWARD THE CENTER THEREOF AT SPACED INTERVALS TO PROVIDE A PLURALITY OF RELATIVELY SLENDER FIN MEMBERS EACH CONNECTING WITH AN UNSLIT CENTER SECTION EXTENDING LENGTHWISE OF SAID STRIP, FOLDING OPPOSITE SIDE PORTIONS OF SAID STRIP INCLUDING SAID SLENDER FIN MEMBERS AND NARROW PORTIONS OF PREDETERMINED WIDTH OF SAID CENTER SECTION MATERIALLY LESS THAN ONE-HALF THE WIDTH OF SAID CENTER SECTION TOWARD EACH OTHER TO FORM A SUBSTANTIALLY U-SHAPED CROSS SECTION WITH SAID SIDE PORTIONS INCLUDING SAID NARROW PORTIONS AND SAID FIN MEMBERS CONSTITUTING THE RESPECTIVE ARMS OF SAID USHAPED CROSS SECTION AND THE REMAINING UNFOLDED PORTION OF SAID CENTER SECTION FORMING THE BASE OF SAID U-SHAPED CROSS SECTION, FOLDING SAID NARROW PORTIONS OVER THE REMAINING PORTION OF SAID CENTER SECTION TO FORM DOUBLE THICKNESS EDGES ON OPPOSITE SIDES OF THE REMAINING PORTION OF SAID CENTER SECTION WHILE SIMULTANEOUSLY BENDING SAID SLENDER FIN MEMBERS IN THE OPPOSITE DIRECTION TO RETAIN SAID SLENDER FIN MEMBERS DIRECTED PEREPENDICULARLY OUTWARDLY FROM SAID REMAINING PORTION OF SAID CENTER SECTION AND SO AS TO BE IN SPACED APART RELATION WITH EACH OTHER DUE TO THE PREDETERMINED WIDTH OF SAID FOLDED NARROW PORTIONS OF SAID CENTER SECTION, COATING SAID TUBING WITH AN ADHESIVE AND HELICALLY WRAPPING SAID STRIP OF SHEET STOCK FORMED BY THE PRECEDING STEPS ONTO SAID TUBING WITH SAID DOUBLE THICKNESS EDGE PORTIONS OF EACH WRAP LYING CLOSELY ADJACENT THE DOUBLE THICKNESS EDGE PORTIONS OF THE WRAPS ON OPPOSITE SIDES THEREOF AND WITH SAID SLENDER FIN MEMBERS EXTENDING GENERALLY RADIALLY OUTWARD THEREFROM, WHEREBY THE FIN MEMBERS OF ADJACENT WRAPS ARE SPACED FROM EACH OTHER BY SAID ADJACENT DOUBLE THICKNESS EDGE PORTIONS.

Claim 2

THE METHOD OF MAKING AN EXTENDED SURFACE HEAT EXCHANGE UNIT COMPRISING THE STEPS OF PROVIDING A LENGTH OF TUBING AND A LONGITUDINAL STRIP OF SHEET STOCK, SLITTING SAID STRIP OF SHEET STOCK INWARDLY FROM ITS OPPOSITE SIDES TOWARD THE CENTER THEREOF AT SPACED INTERVALS TO PROVIDE A PLURALITY OF RELATIVELY SLENDER FIN MEMBERS EACH CONNECTING WITH AN UNSLIT CENTER SECTION EXTENDING LENGTHWISE OF SAID STRIP, FOLDING OPPOSITE SIDE PORTIONS OF SAID STRIP INCLUDING SAID SLENDER FIN MEMBERS AND NARROW PORTIONS OF PREDETERMINED WIDTH OF SAID CENTER SECTION MATERIALLY LESS THAN ONE-HALF THE WIDTH OF SAID CENTER SECTION TOWARD EACH OTHER TO FORM A SUBSTANTIALLY U-SHAPED CROSS SECTION WITH SAID SIDE PORTIONS INCLUDING SAID NARROW PORTIONS AND SAID FIN MEMBERS CONSTITUTING THE RESPECTIVE ARMS OF SAID USHAPED CROSS SECTION AND THE REMAINING UNFOLDED PORTION OF SAID CENTER SECTION FORMING THE BASE OF SAID U-SHAPED CROSS SECTION, FOLDING SAID NARROW PORTIONS OVER THE REMAINING PORTION OF SAID CENTER SECTION TO FORM DOUBLE THICKNESS EDGES ON OPPOSITE SIDES OF THE REMAINING PORTION OF SAID CENTER SECTION WHILE SIMULTANEOUSLY BENDING SAID SLENDER FIN MEMBERS IN THE OPPOSITE DIRECTION TO RETAIN SAID SLENDER FIN MEMBERS DIRECTED PEREPENDICULARLY OUTWARDLY FROM SAID REMAINING PORTION OF SAID CENTER SECTION AND SO AS TO BE IN SPACED APART RELATION WITH EACH OTHER DUE TO THE PREDETERMINED WIDTH OF SAID FOLDED NARROW PORTIONS OF SAID CENTER SECTION, COATING SAID TUBING WITH AN ADHESIVE AND HELICALLY WRAPPING SAID STRIP OF SHEET STOCK FORMED BY THE PRECEDING STEPS ONTO SAID TUBING WITH SAID DOUBLE THICKNESS EDGE PORTIONS OF EACH WRAP LYING CLOSELY ADJACENT THE DOUBLE THICKNESS EDGE PORTIONS OF THE WRAPS ON OPPOSITE SIDES THEREOF AND WITH SAID SLENDER FIN MEMBERS EXTENDING GENERALLY RADIALLY OUTWARD THEREFROM, WHEREBY THE FIN MEMBERS OF ADJACENT WRAPS ARE SPACED FROM EACH OTHER BY SAID ADJACENT DOUBLE THICKNESS EDGE PORTIONS.