Abstract: Each header tank includes a tank body and a header plate. The tank body includes a top wall, shorter side walls, and longer side walls. Each shorter side wall has joining portions integrally formed via rounded connection portions and extending along the inner surfaces of the longer side walls. The header plate includes a closure wall, shorter side walls, and longer side walls. End portions of each longer side wall of the tank body are curved along the rounded connection portions to form first bent portions. End portions of each longer side wall of the header plate are curved along the first bent portions to form second bent portions. The shorter side walls of the header plate have deformation portions which enter recesses formed between the rounded connection portions of the tank body and tip end surfaces of the first bent portions.

Abstract: Each header tank includes a tank body and a header plate. The tank body includes a top wall, shorter side walls, and longer side walls. Each shorter side wall has joining portions integrally formed via rounded connection portions and extending along the inner surfaces of the longer side walls. The header plate includes a closure wall, shorter side walls, and longer side walls. End portions of each longer side wall of the tank body are curved along the rounded connection portions to form first bent portions. End portions of each longer side wall of the header plate are curved along the first bent portions to form second bent portions. The shorter side walls of the header plate have deformation portions which enter recesses formed between the rounded connection portions of the tank body and tip end surfaces of the first bent portions.

Abstract: A refrigerant tube for use in heat exchangers comprises a flat tube having parallel refrigerant passages in its interior and comprising upper and lower walls and a plurality of reinforcing walls connected between the upper and lower walls, the reinforcing walls extending longitudinally of the tube and spaced apart from one another by a predetermined distance. The reinforcing walls are each formed with a plurality of communication holes for causing the parallel refrigerant passages to communicate with one another therethrough. Each of the reinforcing walls is 10 to 40% in opening ratio which is the proportion of all the communication holes in the reinforcing wall to the reinforcing wall.

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.

Abstract: A refrigerant tube for use in heat exchangers comprises a flat aluminum tube having parallel refrigerant passages in its interior and comprising flat upper and lower 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. The reinforcing walls are each formed with communication holes for causing the parallel refrigerant passages to communicate with one anther therethrough. The flat aluminum tube is prepared from upper and lower two aluminum sheets by bending opposite side edges of the lower aluminum sheet to a raised form and joining the bent edges to the respective side edges of the upper aluminum sheet which is flat so as to form a hollow portion. The reinforcing walls are formed by joining to the inner surface of the upper wall ridges projecting inward from the lower wall.

Abstract: A refrigerant tube for use in heat exchangers comprises a flat aluminum tube having parallel refrigerant passages in its interior and comprising flat upper and lower 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. The reinforcing walls are each formed with communication holes for causing the parallel refrigerant passages to communicate with one anther therethrough. The flat aluminum tube is prepared from upper and lower two aluminum sheets by bending opposite side edges of the lower aluminum sheet to a raised form and joining the bent edges to the respective side edges of the upper aluminum sheet which is flat so as to form a hollow portion. The reinforcing walls are formed by joining to the inner surface of the upper wall ridges projecting inward from the lower wall.

Abstract: A refrigerant tube for use in heat exchangers comprises a flat aluminum tube having parallel refrigerant passages in its interior and comprising flat upper and lower 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. The reinforcing walls are each formed with communication holes for causing the parallel refrigerant passages to communicate with one anther therethrough. The flat aluminum tube is prepared from upper and lower two aluminum sheets by bending opposite side edges of the lower aluminum sheet to a raised form and joining the bent edges to the respective side edges of the upper aluminum sheet which is flat so as to form a hollow portion. The reinforcing walls are formed by joining to the inner surface of the upper wall ridges projecting inward from the lower wall.

Abstract: A refrigerant tube for use in heat exchangers comprises a flat aluminum tube having parallel refrigerant passages in its interior and comprising flat upper and lower 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. The reinforcing walls are each formed with communication holes for causing the parallel refrigerant passages to communicate with one anther therethrough. The flat aluminum tube is prepared from upper and lower two aluminum sheets by bending opposite side edges of the lower aluminum sheet to a raised form and joining the bent edges to the respective side edges of the upper aluminum sheet which is flat so as to form a hollow portion. The reinforcing walls are formed by joining to the inner surface of the upper wall ridges projecting inward from the lower wall.

Abstract: A tube for heat exchangers is a flat tube which either includes a pair of plane walls which are spaced a predetermined distance from one another, the plane walls respectively having one lateral ends integrally connected to each other by a U-shaped bent portion, the plane walls further having their other lateral ends which abut against to be tightly secured to one another, or alternatively, the flat tube includes as the plane walls a pair of preformed plates having the abutted and soldered portions at both lateral ends. The tube further includes one or more curved lugs integral with and protruding inwardly from an inner surface of each plane wall, and the curved lugs respectively having innermost tops so that the innermost tops protruding from one plane wall bear against the inner surface of the other plane wall or against the innermost tops of the other curved lugs protruding from said other plane wall.

Abstract: A tubular body having a pipe joint member attached to the peripheral wall thereof and communicating with the interior of the tubular body. The peripheral wall of the tubular body includes a curved wall portion having a circular-arc cross section and formed with a hole. The joint member has an outward flange at an intermediate portion of its length and a tubular portion positioned beyond the outward flange toward one end of the joint member and has its outer end inserted in the hole in the tubular body curved wall portion. The outward flange of the joint member is brazed to the outer surface of the tubular body curved wall portion with a brazing ring which is fitted around the joint member tubular portion and positioned outside the tubular body. The brazing ring is made of a brazing sheet including cladding of brazing material over each of its opposite surfaces and has one surface joined to the outward flange and the other surface joined to the outer surface of the curved wall portion.

Abstract: A tubular body according to the present invention has a pipe joint member attached to the peripheral wall thereof and communicating with the interior of the tubular body. The peripheral wall of the tubular body includes a curved wall portion having a circular-arc cross section and formed with a hole. The joint member has an outward flange at an intermediate portion of its length and a tubular portion positioned beyond the outward flange toward one end of the joint member and has its outer end inserted in the hole in the tubular body curved wall portion. The outward flange of the joint member is brazed to the outer surface of the tubular body curved wall portion with a brazing ring which is fitted around the joint member tubular portion and positioned outside the tubular body.

Abstract: A tube for heat exchangers is a flat tube which either comprises a pair of plane walls which are spaced a predetermined distance from one another, the plane walls respectively having lateral ends integrally connected to each other by a U-shaped bent portion, the plane walls further having other lateral ends which abut against and are tightly secured to one another, or alternatively, the flat tube comprises a pair of preformed plates having abutted and soldered portions at both lateral ends. The tube further comprises one or more curved lugs integral with and protruding inwardly from an inner surface of each plane wall, and the curve lugs respectively have innermost tops so that the innermost tops protruding from one plane wall bear against the inner surface of the other plane wall or against the innermost tops of the other curved lugs protruding from said other plane wall.