Abstract: A metal plate for producing a flat tube including a metal body having a joint portion, first and second flat wall forming portions connected by the joint portion, reinforcing wall forming portions projecting from the first and second flat wall forming portions and extending in a longitudinal direction of the first and second flat wall forming portions, and side wall forming portions projecting from opposite side edges of the metal body, respectively. The joint portion has a ridge which makes the joint portion thicker than the first and second flat wall forming portions. The ridge, the reinforcing wall forming portions and the side wall forming portions are projecting in a same direction. The metal body bends into a hairpin shape at boundaries formed between the ridge of the joint portion and the first and second flat wall forming portions.

Abstract: A flat tube includes a pair of upper and lower walls opposed to each other, two side walls interconnecting the upper and lower walls at left and right opposite side edges thereof, and a covering wall provided over the outer surface of the left side wall and brazed to the left side wall. The left side wall is made from a side wall forming portion projecting downward from the upper wall integrally therewith and a side wall forming portion projecting upward from the lower wall integrally therewith by brazing these portions as butted against each other. The covering wall is made by folding a covering wall forming portion formed by extending one side edge of the upper wall. The left side wall including the wall forming portion of the upper wall and the wall forming portion of the lower wall can be protected.

Abstract: A flat tube making platelike body 15 is in the form of a single metal plate in its entirety and comprises two flat wall forming portions 17, 18 having the same width, a connecting portion 16 for interconnecting these portions 17, 18, side wall forming portions 9, 10 projecting from the respective flat wall forming portions 17, 18 and each formed integrally with one side edge of the flat wall forming portion opposite to the connecting portion 16, and first and second reinforcing wall forming portions 11, 12 integrally formed on each of the flat wall forming portions 9, 10. The first reinforcing wall forming portions 11 are butted against the respective second reinforcing wall forming portions 12 in pairs when the metal plate is folded into a hairpin form at the connecting portion 16. The first reinforcing wall forming portions 11 are given a smaller thickness than the second reinforcing wall forming portions 12 on the other flat wall forming portion 18 butted against the respective portions 11.

Abstract: A rolling apparatus including a first work roll and a second work roll cooperative with the first work roll for rolling a metal blank plate to manufacture a metal product of miscellaneous cross section including a plate portion having one side in the form of a flat surface and a plurality of ridges projecting upright from the other side of the plate portion integrally therewith and spaced from one another. The first work roll has a plurality of ridge forming annular grooves formed in the peripheral surface thereof over the entire circumference of the surface and arranged at a spacing axially of the first work roll. The two work rolls are rotated so that the peripheral speed of the bottom face of the deepest of all the ridge forming annular grooves in the first work roll is not less than the peripheral speed of the peripheral surface of the second work roll.

Abstract: A metal plate comprises two flat wall forming portions 89, 90 connected together by a joint portion 88, a plurality of reinforcing wall forming portions 83, 84 upwardly projecting from each of the wall forming portions 89, 90 integrally therewith, and a side wall forming portion 81, 82 formed at each of opposite side edges of the plate and upwardly projecting therefrom integrally therewith. A projection 85 is formed on the upper end of the reinforcing wall forming portion 83 on the flat wall portion 89, and a recess 86 for the projection 85 to fit in is formed in the upper end of the wall forming portion 84 to be butted against the portion 83 and provided on the other flat wall portion 90. The metal plate satisfies the relationships of: A>a, A/a?1.5, B/b?1.5, C/c?1.5, and D/d/?1.

Abstract: A metal plate comprises two flat wall forming portions 89, 90 connected together by a joint portion 88, a plurality of reinforcing wall forming portions 83, 84 upwardly projecting from each of the wall forming portions 89, 90 integrally therewith, and a side wall forming portion 81, 82 formed at each of opposite side edges of the plate and upwardly projecting therefrom integrally therewith. A projection 85 is formed on the upper end of the reinforcing wall forming portion 83 on the flat wall portion 89, and a recess 86 for the projection 85 to fit in is formed in the upper end of the wall forming portion 84 to be butted against the portion 83 and provided on the other flat wall portion 90. The metal plate satisfies the relationships of: A>a, A/a?1.5, B/b?1.5, C/c?1.5, and D/d/?1.

Abstract: A semifinished flat tube 30 is for use in producing a flat tube 1 comprising an upper and a lower wall 2, 3 opposed to each other, and left and right opposite side walls 4, 5 interconnecting the upper and lower walls 2, 3 at opposite side edges thereof. The semifinished flat tube is produced from a metal plate 15 having two flat first portions 17, 18 for making the upper and lower walls 2, 3, a second portion 16 interconnecting the two first portions 17, 18 integrally for forming the right side wall 5, and two third portions 9, 10 projecting upward from the respective first portions 17, 18 integrally with the first portion each at a side edge thereof opposite to the second portion 16 for making the left side wall 4, by bending the metal plate 15 to the shape of a hairpin at the second portion 16 to cause the third portions 9, 10 to butt against each other.

Abstract: A rolling apparatus including a first work roll and a second work roll cooperative with the first work roll for rolling a metal blank plate to manufacture a metal product of miscellaneous cross section including a plate portion having one side in the form of a flat surface and a plurality of ridges projecting upright from the other side of the plate portion integrally therewith and spaced from one another. The first work roll has a plurality of ridge forming annular grooves formed in the peripheral surface thereof over the entire circumference of the surface and arranged at a spacing axially of the first work roll. The two work rolls are rotated so that the peripheral speed of the bottom face of the deepest of all the ridge forming annular grooves in the first work roll is not less than the peripheral speed of the peripheral surface of the second work roll.

Abstract: A metal plate comprises two flat wall forming portions 89, 90 connected together by a joint portion 88, a plurality of reinforcing wall forming portions 83, 84 upwardly projecting from each of the wall forming portions 89, 90 integrally therewith, and a side wall forming portion 81, 82 formed at each of opposite side edges of the plate and upwardly projecting therefrom integrally therewith. A projection 85 is formed on the upper end of the reinforcing wall forming portion 83 on the flat wall portion 89, and a recess 86 for the projection 85 to fit in is formed in the upper end of the wall forming portion 84 to be butted against the portion 83 and provided on the other flat wall portion 90. The metal plate satisfies the relationships of: A>a, A/a≦1.5, B/b≦1.5, C/c≦1.5, and D/d≦1.

Abstract: A process for producing a flat heat exchange tube having parallel refrigerant passages in its interior and comprising flat upper and lower walls, opposite side walls and a plurality of reinforcing walls connected between the upper and lower walls, extending longitudinally of the tube and spaced apart from one another by a predetermined distance, using a rolling mill including a central work roll and a plurality of planetary work rolls arranged around a portion of the periphery of the central work roll and spaced apart circumferentially thereof, the central work roll being formed with parallel annular grooves in the periphery thereof.