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 duplex heat exchanger comprises unit heat exchangers which have a plurality of tubes arranged parallel with each other and comprise fins each interposed between two adjacent ones of such tubes, opposite ends of each tube being connected to a pair of headers in fluid connection therewith. The unit heat exchangers are closely juxtaposed to each other fore and aft in a direction of air flow. Coolant circuits of said unit heat exchangers are connected either in series or in parallel with each other.

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 pipe joint comprises a pipe having a spigot formed with an annular projection on an outer periphery of an end portion of the pipe, a member having a socket including a tubular portion for receiving the spigot therein and formed with an aperture in a peripheral wall of the tubular portion, the socket being internally formed with a bearing portion for receiving and bearing on the annular projection when the spigot is inserted into the socket, a resilient stopper mountable on the tubular portion of the socket and having a fitting portion fittable in the aperture, and a tubular stopper holder capable of covering the stopper. The stopper holder is so fixed as to cover the stopper by a recess formed in an outer surface of the stopper and an inward protrusion formed on the stopper holder and fittable in the recess.

Abstract: A duplex heat exchanger of the so-called stacked type has in principle a plurality of plate-shaped tubular elements (1) which are stacked side by side or one on another and a plurality of fins (2) each intervening between the adjacent tubular elements. Each tubular element is composed of flat tubular segments (3a, 4a) separated from each other and each communicating with one of bulged header portions (3b, 4b) of the tubular element, so that flow paths (3, 4) for heat exchanging media are formed through each tubular element. Two or more unit heat exchangers (X, Y) are defined integral with each other within the duplex heat exchanger, since the adjacent tubular elements (1) communicate with each other through the header portions (3b, 4b).

Abstract: A raw aluminum foil for use to prepare electrolytic condenser electrodes has an aluminum purity of 99.9% or higher and contains 50-500 ppm of Mg. A method of etching the raw foil to prepare the electrodes consists of a primary etching step and a secondary etching step, and the primary etching is conducted in an aqueous bath containing 3-10% by weight of HCl and 10-40% by weight of H.sub.2 SO.sub.4, at 70.degree.-90.degree. C. and with a current density of 10-40 A/dm.sup.2. The secondary etching is conducted electrolytically or chemically in a further bath containing 3-10% by weight of HCl, with or without 1% or less of H.sub.2 C.sub.2 O.sub.4 added to the further bath, at a bath temperature of 70.degree.-95.degree. C. and with a current density of 0-10 A/dm.sup.2.

Abstract: An aluminum alloy brazing agent containing a flux is made by compacting a powder mixture of a matrix powder and a flux powder at a first temperature so as to form a rigid piece, and then conducting a secondary forming of the rigid piece into a desired shape at a second temperature. The first temperature is lower than 480.degree. C., preferably lower than 400.degree. C., and more preferably room temperature, so that the compacting may be conducted in the air. The second temperature is 300.degree.-575.degree. C. for the secondary forming, which also may preferably be conducted in an non-oxidizing atmosphere, so that the brazing agent can be of an improved capability of brazing aluminum articles and be produced inexpensively.

Abstract: An elastic mount comprising: an outer hollow member which is formed of an aluminum alloy and has an inner hole; an inner shaft member which extends in the inner hole of the outer member; an elastic member which is formed by vulcanization of a rubber material in the inner hole between the outer member and the inner member to elastically connect the outer and inner members to each other; the outer member having an inner circumferential surface including a plurality of recesses and a plurality of protrusions which cooperate with each other to define the inner hole and each of which continuously extends in an axial direction of the inner hole; the recesses and the protrusions being alternate with each other at a pitch of 0.5 mm to 2.0 mm in a circumferential direction of the inner hole; a top end of each of the protrusions having a height of 0.3 mm to 1.

Abstract: Sliced workpieces severed from a metal extrusion transversely of it and into a desired thickness, or bent ones made from the extruded metal pipes, are restrained at their regulated correct positions each in its entirety or in part. Subsequently, the workpieces are compressed in a direction to the thickness or in the direction perpendicular to the primary bending direction. Plastic deformation of or exceeding 0.5%, or more preferably 2-5%, will be produced in each workpiece. Alternatively, those sliced or bent workpieces may be pressed in a direction to that of thickness or in the direction perpendicular to a previous bending, after each workpiece is restrained in its entirety or in part at the regulated correct dimension.

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 clamper (12) has a clamp finger (12a) for gripping a joint pipe (5), and is preliminarily attached to a preassembly of a heat exchanger. The clamp finger (12a) is deformed to embrace the joint pipe (5), before the preassembly is subjected to the so-called one-shot brazing process. Thereafter, the joint pipe (5) is brazed to and become integral with the clamp finger (12a) which is embracing the joint pipe, at the same time as the essential parts incorporated in the heat exchanger preassembly are brazed one to another. Thus, the clamper (12) not only serves as a supporter for keeping the joint pipe (5) in place after the brazing, but also functions as a jig of such a kind as holding in place the joint pipe (5) in the unbrazed assembly of the heat exchanger, thus improving the manufacture efficiency of heat exchangers.

Abstract: An aluminum weldment is produced by resistance-welding aluminum workpieces, and has a nugget formed between the aluminum workpieces which contains more magnesium than the base material of the aluminum workpieces. The nugget contains 5.about.17 wt % of magnesium which forms a solid solution with aluminum.

Abstract: A brazeable aluminum material is composed of an aluminum core and a brazing agent layer consisting of a brazing agent thermally sprayed onto covering a surface of the core. A number of unmolten minute particles of the brazing agent are present in the brazing agent layer, which contains at least an aluminum-silicon alloy and/or a mixture of aluminum and silicon. Characteristic features of a method of producing the brazeable aluminum material are the steps of: preparing a powder composed of minute particles; and thermally spraying the powder onto the aluminum core in such a state that only a surface of each minute particle is molten, with a pith of the particle remaining unmolten. The powder is an Al-Si alloy and/or a mixture of Al powder and Si powder.

Abstract: A pipe joint for joining two pipes end to end comprises a hollow cylindrical spigot portion having an annular projection on the outer periphery of a base end thereof, a hollow cylindrical socket portion having an inside diameter approximately equal to the outside diameter of the spigot portion and formed with two opposed apertures in its peripheral wall close to a forward end thereof and with a stepped part on the inner surface of the peripheral wall for the projection to come into contact with, the stepped part being closer to a base end of the socket portion than the apertures, and a stopper having a pair of circular-arc resilient legs fittable into the respective apertures from outside to project inward and each having a slanting inner surface, the legs being opposed to each other for the inwardly curved surfaces thereof to face each other.

Abstract: A brazeable aluminum material is composed of an aluminum core and a brazing agent layer consisting of a brazing agent thermally sprayed onto and covering a surface of the core. A number of unmolten minute particles of the brazing agent are present in the brazing agent layer, which contains at least an aluminum-silicon alloy and/or a mixture of aluminum and silicon. Characteristic features of a method of producing the brazeable aluminum material are the steps of: preparing a powder composed of minute particles; and thermally spraying the powder onto the aluminum core in such a state that only a surface of each minute particle is molten, with a pith of the particle remaining unmolten. The powder is an Al-Si alloy and/or a mixture of Al powder and Si powder.

Abstract: In a method of producing twisted aluminum products, an elongate heat-treatable aluminum article is twisted at first to have a value "tan .phi." of 0.5 or more, with the term .phi. denoting a helical angle of the thus twisted article. The twisted aluminum article is then subjected to a solid solution treatment and the step of aging, in this order.

Abstract: A heat exchanger has tubes inserted in headers easily to a given depth, and also has brackets which are readily attached to the headers. Each of the headers (3, 4) is divided into an inner half (5) and an outer half (6) facing the inner half in which apertures (5a) for receiving ends of the tubes are formed. The bracket (12) having a fastenable rib (12c) is fitted on the header over its halves (5, 6) so that these halves are made immovable relative to each other. Alternatively, the outer half (6) of the header may have a pair of embracing portions (12a) which fit on lateral sides of the inner half (5) so as to hold it in place.

Abstract: A condenser adapted for use in the car cooling system, the condenser comprising a pair of headers provided in parallel with each other; a plurality of tubular elements whose opposite ends are connected to the headers; fins provided in the air paths between one tube and the next; wherein each of the headers is made of a cylindrical pipe of aluminum; wherein each of the tubular elements is made of a flat hollow tube of aluminum by extrusion; and wherein the opposite ends of the tubular elements are inserted into slits produced in the headers so that they are liquid-tightly soldered therein. The questions raised in reexamination request No. 90/003,919, filed Aug. 7, 1995, have been considered and the results thereof are reflected in this reissue patent which constitutes the reexamination certificate required by 35 U.S.C. 307 as provided in 37 CFR 1.570(e).This is a Reissue of a Patent which was the subject of a Reexamination Certificate No. B1 5,190,100, dated Aug. 30, 1994, Request No. 90/003,073, Jun. 3, 1993.

Abstract: A condenser adapted for use in the car cooling system, the condenser comprising a pair of headers provided in parallel with each other; a plurality of tubular elements whose opposite ends are connected to the headers; fins provided in the air paths between one tube and the next; wherein each of the headers is made of a cylindrical pipe of aluminum; wherein each of the tubular elements is made of a flat hollow tube of aluminum by extrusion; and wherein the opposite ends of the tubular elements are inserted into slits produced in the headers so that they are liquid-tightly soldered therein.The question raised in reexamination request Nos. 90/003,544, filed Aug. 24, 1994, 90/003662, filed Dec. 16, 1994, 90/003796, filed Apr. 19, 1995, have been considered and the results thereof are reflected in this reissue patent which constitutes the reexamination certificate required by 35 U.S.C. as provided in 37 CFR 1.570(e).

Abstract: A condenser apparatus includes a pair of headers provided in parallel with each other; a plurality of tubular elements whose opposite ends are connected to the headers; and fins provided in the air paths between one tube and the next. Each of the headers is made of a cylindrical pipe of aluminum. At least one of the headers is internally divided by a partition into at least two groups of coolant passageways, thus enabling the flow of coolant to make at least one U-turn in the header. The partition extends into the header through a slit in the header. Each of the tubular elements is made of a flat hollow tube of aluminum. The opposite ends of the tubular elements are inserted into slits produced in the headers so that they are liquid-tightly secured.