Turbulizers and method for forming same

A method of forming apparatus for use as a turbulizer or fin for a heat exchanger, the apparatus including a member having a longitudinal axis, a lateral width and a plurality of strips including one or more first strips and one or more second strips, each strip extending widthwise of the apparatus and being corrugated longitudinally so as to form a plurality of sections laterally spaced-apart from one another and connected to one another by bridges projecting from the sections in a common direction with respect to each strip, wherein each of the one or more first strips and each of the one or more second strips has a profile which differs from that of the longitudinally-corrugated strip, wherein the bridges of the first strips and the second strips extend in the same direction and the corrugations of the one or more second strips are offset laterally from the corrugations of the one or more first strips, the method comprising:

• crimping a longitudinally-corrugated strip between a core die and a cavity die to form said turbulizer,
• wherein each corrugation of said longitudinally-corrugated strip has a flat surface and parallel sidewalls extending substantially perpendicularly from opposite sides of the flat surface;
• and
• wherein each bridge of the first strip and second strip is formed by a flat surface of the core die which impinges upon and in coplanar relation with the flat surface of a respective corrugation as crimping commences.

A method of forming, from a longitudinally-corrugated strip, apparatus for use as a turbulizer or fin for a heat exchanger, the apparatus including a member having a longitudinal axis, a lateral width and a plurality of strips including one or more first strips, one or more second strips and one or more third strips, each strip extending widthwise of the apparatus and being corrugated longitudinally so as to form a plurality of sections laterally spaced-apart from one another and connected to one another by bridges projecting from the sections in a common direction with respect to each strip, wherein each of the one or more first strips and the one or more second strips has a profile which differs from that of the longitudinally-corrugated strip, wherein the bridges of the first strips and the second strips extend in the same direction and the corrugations of the one or more second strips are offset laterally from the corrugations of the one or more first strips, the method comprising:

• a forming step, wherein first and second forming dies move between an open position and a closed position to engage the corrugated strip between them to form said turbulizer, characterized in that substantially all lateral movement of longitudinally-corrugated strip material in the forming step occurs as a result of said strip material being drawn laterally by a laterally-connected portion of said strip material that has been displaced in a direction parallel to the direction of relative die movement.