Abstract: Workpieces of aluminum alloy are resistance-welded while a powdery mixture of magnesium and a metal oxide is being interposed between regions of workpieces of aluminum alloy which are to be joined to each other. The metal oxide may comprise at least one material selected from the group consisting of TiO.sub.2, SiO.sub.2, Cr.sub.2 O.sub.3, MnO.sub.2, Fe.sub.2 O.sub.3, CuO, and Ti.sub.2 O.sub.3 and the powdery mixture may include aluminum powder. The workpieces may be made of aluminum, stainless steel, or the like rather than aluminum alloy.

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 brazing agent consists essentially of a compacted powder mixture of an aluminum-silicon alloy and a flux, the agent having an apparent density of 90% or more of a theoretical density. Si is contained at about 3-15% by weight of all the elements other than the flux, so that the ratio in weight of all the elements to the flux is from 99.9:0.1 to 70:30. The brazing agent may further contain one or more elements selected from a group consisting of zinc, tin and indium, at about 0.1-5%, 0.01-0.5% and 0.01-0.5% by weight of all the elements other than the flux, respectively. A brazing sheet may be of such a structure that a core sheet made of aluminum or its alloy has at least one surface clad with a skin layer which has a thickness of 10 .mu.m or more for each surface.

Abstract: A heat exchanger has flat tubes (1) parallelly arranged and spaced apart from each other a predetermined distance in the direction of thickness. The heat exchanger further has a pair of headers (5, 6) to which the ends of the tubes are connected in fluid communication. Each tube (1) has an intermediate bent portion (4) and straight sections (2, 3) separated one from another by the bent portion, and the bent portion (4) is a portion twisted at a predetermined helical angle relative to each straight section. Fins (11) are interposed between the adjacent straight sections (2), and further fins (12) between the other straight sections (3). The heat exchanger is easy to manufacture and of an improved efficiency of heat exchange, in spite of the tubes being bent in the direction of their width.

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 heat exchanger has tubes and headers, with each tube having both ends connected to the headers in fluid communication. A blockish joint of the flange connection type is attached to one header, and an inlet port and an outlet port are formed in the joint. One or two blockish connectors also of the flange connection type and fixed to ends of external pipings are connected to the joint, such that an effective core area of the heat exchanger is increased, and an operation for connecting the external pipings is rendered simpler and more efficient.

Abstract: A stack type evaporator including tubular elements 1 each having a plurality of inwardly protruding recessed ribs 7 which extend from an upper header portion 1a of the element to a lower header portion 1b, with the ribs serving as straight drain canals 7a. A hydrophilic resin coating of a specific composition covers the outer surfaces of the tubular elements 1 and fins 2 each interposed between two adjacent tubular elements. The combination of straight drain canals with the specific hydrophilic resin coating is effective to facilitate the drainage of condensed water so that the waterdrops are perfectly prevented from flying out of the evaporator, and that any stinking mold or mildew is not permitted to grow within a reduced amount of remaining adherent water. Also, the hydrophilic coating itself does not emit any unpleasant smell which has been inevitable to the prior art water glass coating, thus an air-conditioned environment always remains comfortable.

Abstract: A heat exchanger comprises a main body and at least one header-held members, with the main body having a plurality of heat exchanging tubes whose both ends are connected to headers in fluid communication with them, wherein the header-held members are selected from a group consisting of a bracket and an external pipe-connecting member which are attached to the header. The header-held members each comprise a header-surrounding portion which is fitted sideways on and then brazed to the header while remaining self-retained on it, whereby the header-held member can be easily and rigidly secured to the header.

Abstract: In a method of hot brazing aluminum articles, the steps of: interposing an amount of a flux-containing brazing agent (12) between portions of aluminum articles (11, 11) which are to be adjoined one to another; gripping the portions with a pair of heaters (13); and then activating the heater so that heat conducted therefrom melts the brazing agent (12) to braze the aluminum articles (11), are carried out in this order. The brazing agent (12) is a compacted agent composed of a matrix powder and a flux powder, at a ratio in weight of 99.9:0.1 to 70:30, and the agent has a density corresponding to 90% or more of a theoretical value.

Abstract: An end holder (5) has a main recess (8) and cavities (8a) to fit on an end of an extruded aluminum profile material (1) having a semi-hollow portions (1a). Each of chucks (6) can protrude into the semi-hollow portion placed in the cavity (8a) so as to chuck the inner surface of said portion (1a), so that the end of material (1) can be firmly held in place while it is being severed from a body of the material to thereby produce high quality slices of an improved precision in dimension and shape.

Abstract: A heat exchanger has tubes and headers, with each tube having both ends connected to the headers in fluid communication. A blockish joint of the flange connection type is attached to one header, and an inlet port and an outlet port are formed in the joint. One or two blockish connectors also of the flange connection type and fixed to ends of external pipings are connected to the joint, such that an effective core area of the heat exchanger is increased, and an operation for connecting the external pipings is rendered simpler and more efficient.

Abstract: In a continuous surface treating method and apparatus with an inline centrifugal separator, an object to be treated is contained in a basket and hung from a hanger of an overhead type and a series of surface treatments of the object is carried out by using a continuous conveyer of a power and free type. By using a hanger attach-detach conveyer, the object is moved from a main conveyer to a sub-conveyer and an excessive treating liquid attached to the object in a previous process is separated by using the centrifugal separator. Then, the object is returned from the sub-conveyer to the main conveyer to perform a next process. The surface treating apparatus includes the rotatable basket for containing the object.

Abstract: A condenser for use in air conditioning systems, including a core and headers, the core comprising tubes and corrugated fins sandwiched between the tubes, wherein:width of each tube: 6.0 to 20 mmheight of each tube: 1.5 to 7.0 mmheight of each coolingmedium flow path: 1.0 mm or moreheight of each fin: 6.0 to 16 mmfin pitch: 1.6 to 4.

Abstract: A heat exchanger has a plurality of flat tubes which alternate with fins, and the tubes and the fins are disposed one on another. Both ends of each tube are connected to a pair of right-hand and left-hand headers, in fluid communication with them. The headers have their ends closed with caps, and each cap has a pin integral with it so as to hold in place a bracket which is used to mount the heat exchanger on a structural base. The integral pins protrude upwards or downwards from the caps.

Abstract: A cylinder tube comprising an aluminum tube formed on its outer surface with an outside oxide film having a hardness of not lower than 150 HV to less than 350 HV and on its inner surface with an inside oxide film having a hardness of not lower than 350 HV to not higher than 650 HV.

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 exhaust gas recycling device for use in reducing the nitrogen oxide (NO.sub.x) concentration of exhaust gases from gasoline engines has between two metal plates superposed on each other a main channel defined by a first inflated portion of large cross section, and at least one branch channel defined by a second inflated portion communicating with the main channel and having a small cross section. The device comprises a single component provided by two metal plates, and is simple in construction and reduced in the number of parts, manufacturing cost and weight. The device is produced by roll-bonding two metal plates, forming at least one second inflated portion having a small cross section and defining the branch channel by primary inflation with a low fluid pressure, thereafter holding the two metal plates with dies, and forming a first inflated portion having a large cross section and defining the main channel by secondary inflation with a high fluid pressure.

Abstract: A heat sink having pin-shaped fins, for example, for use in disposing of heat in printed boards for computers comprises a heat dissipating base plate and a plurality of comblike fin members arranged in parallel at a predetermined spacing on one surface of the base plate approximately perpendicular thereto, each of the fin members comprising pin-shaped fins arranged in a row and connector connecting the fins together each at one end thereof, the connector of each fin member being joined to the surface of the base plate. The fins are given a greater height and arranged with a reduced pitch with a higher density for disposal of increased amounts of heat. To prepare the heat sink, the fin members are blanked out from a metal sheet, the fin members and spacer plates are arranged alternately on one surface of a heat dissipating base plate approximately perpendicular thereto, the connectors of the fin members are joined to the base plate and the spacer plates are thereafter removed.

Abstract: Aluminum foils used as a material of electrodes in electrolytic capacitors are manufactured by a method which comprises a step of forming at first an initial internal oxide coating 5 to 50 .ANG. thick on the surface of the aluminum foils before they are electrochemically or chemically etched later. The aluminum foils are then subjected to high temperature heat treatment such that the whole thickness of the oxide coating does not exceed 70 .ANG..

Abstract: In brazing a first metal piece having a tubular joint portion of predetermined length at an end thereof and a second metal piece having a bore for inserting the extremity of the joint portion thereinto by replaced brazing with the extremity of the joint portion inserted in the bore, a plurality of axial grooves having a depth of 0,3 to 1,5 mm and arranged at a spacing of 5 to 30 mm in the circumferential direction are formed in the outer peripheral surface of joint portion of the first metal piece. Each of the grooves has one end extending to the outside of the bore of the second metal piece when the joint portion is inserted in the bore. The gas or residue of flux produced during brazing escapes through the grooves, whereby voids or like defects are prevented from occurring in the fillet of the brazed joint. Since the grooves are all filled up with the brazing filler metal, the brazed joint is given a sufficient bond strength and prevented from permitting leakage there-through.