Tube for heat exchangers and a method for manufacturing the tube

A tube for heat exchangers, the tube comprising:

• a pair of preformed plates spaced a predetermined distance from one another;
• the preformed plates being tightly secured to one another at both lateral ends to define a flat configuration of the tube;
• one or more curved lugs protruding inwardly from an inner surface of each preformed plate, said lugs being folded, two-ply portions of the plates, the lugs and the remaining portion of each plate being a one-piece, integral unit;
• and
• the curved lugs respectively having innermost tops, wherein the innermost tops of the curved lugs protruding from one preformed plate bear against and are fixedly secured to the inner surface of the other preformed plate or to the innermost tops of the other curved lugs protruding from said other preformed plate.

A tube for heat exchangers, the tube comprising:

• a pair of plane walls spaced a predetermined distance from one another;
• each plane wall having a lateral end integrally connected to the lateral end of the other wall by a U-shaped bent portion;
• each plane wall having an opposite lateral end fixedly secured to the opposite lateral end of the other wall to define a flat configuration for the tube;
• at least one curved lug in each plane wall, said lug being an integral portion of the plane wall;
• the curved lug of one plane wall protruding toward the other plane wall and having an innermost top which bears against and is secured to the inner surface of the other plane wall or to the innermost top of a curved lug of the other plane wall;
• the opposite lateral ends including creased edges which abut one another and are fixedly secured to each other, said creased edges extending in parallel inwardly of the tube.

A tube for heat exchangers, the tube comprising:

• a pair of preformed plates spaced a predetermined distance from one another;
• the preformed plates being tightly secured to one another at both lateral ends to define a flat configuration for the tube;
• one or more curved integral with and protruding inwardly from an inner surface of each preformed plate;
• the curved lugs respectively having innermost tops, wherein the innermost tops of the curved lugs protruding from one preformed plate bear against and are secured to the inner surface of the other preformed plate or to the innermost tops of the other curved lugs protruding from said other preformed plate;
• both lateral ends of the preformed plates including L-shaped bent portions which abut in parallel with one another and are fixedly secured together, said L-shaped bent portions protrude outwardly of the tube;
• the bent portion of one preformed plate including at least one rib which protrudes toward the other preformed plate to penetrate a hole formed through the other L-shaped bent portion of the other preformed plate, wherein the top of the rib is distressed to retain the rib in the hole.