Abstract: An improved method for assembly of a brazed condenser unit for use in an automobile air conditioning system is provided which significantly reduced the defective rate due to leaky internal joints within the condenser. A sufficiently viscous flux composition is applied to the internal features of the condenser during assembly. The flux composition is specifically applied to surfaces of the aluminum alloy header which is clad internally with the brazing alloy, so as to promote complete and consistent brazing of the internal tubes and components. The brazing flux composition of this invention consists of potassium fluoaluminate particles in a liquid carrier consisting of a polyhydric alcohol, e.g., propylene glycol, and minimal amounts of water. This flux composition has a sufficiently high viscosity so as to permit its easy, consistent deposition on the header surface without subsequent displacement during assembly and processing.

Abstract: An improved aluminum alloy brazing stock material is provided for use in a tubeplate-and-center type evaporator within an automobile air conditioning system. The improved aluminum alloy brazing stock contains a unique aluminum alloy core material that has been clad on both sides with an appropriate aluminum-silicon brazing alloy. The inventive aluminum alloy core material is characterized by a higher copper concentration and a lower manganese concentration as compared to conventional aluminum alloys used in these types of automotive evaporator units. An air conditioning evaporator unit from the aluminum alloy brazing stock material of this invention is characterized by enhanced corrosion resistance. In addition, the brazing stock material of this invention is sufficiently ductile to be stamped at room temperature and exhibits good strength even over the extensive thermal cycling characteristic of an automotive environment.

Abstract: A method of brazing a temporarily assembled heat exchanger includes the steps of spraying an ionized fluid such as water on one surface. A powdered electrostatically charged flux is blown onto the opposite surface of the heat exchanger. A portion of the powdered flux is attracted to the one surface by the ionized fluid. Therefore, the flux material is uniformly spread across the heat exchanger. Finally, the heat exchanger is heated and brazed.

Abstract: A convection braze furnace for brazing aluminum heat exchangers in an inert gas rich atmosphere includes entrance and exit vestibules forming atmosphere barriers of suspended stainless steel strips. The interior of the braze furnace is divided into multiple zones for progressively heating the heat exchangers to a brazing temperature and then cooling the heat exchangers in the final zone. An impeller circulates the heated inert gas atmosphere within each zone to accelerate heat transfer. A chain type conveyor supports the heat exchangers as they are moved through the braze furnace. An isolated return tube surrounds the lower return side of the conveyor chain as it passes through the braze furnace. The braze furnace housing is comprised of inner and outer shells having an inert gas pressurized cavity interstitial therebetween. The inner shell includes a plurality of expansion strips having generally ellipsoidal corner expansion joints.

Abstract: A convection braze furnace for brazing aluminum heat exchangers in an inert gas rich atmosphere includes entrance and exit vestibules forming atmosphere barriers of suspended stainless steel strips. The interior of the braze furnace is divided into multiple zones for progressively heating the heat exchangers to a brazing temperature and then cooling the heat exchangers in the final zone. An impeller circulates the heated inert gas atmosphere within each zone to accelerate heat transfer. A chain type conveyor supports the heat exchangers as they are moved through the braze furnace. An isolated return tube surrounds the lower return side of the conveyor chain as it passes through the braze furnace. The braze furnace housing is comprised of inner and outer shells having an inert gas pressurized cavity interstitial therebetween. The inner shell includes a plurality of expansion strips having generally ellipsoidal corner expansion joints.

Abstract: A condenser having single piece roll formed condenser tubes that are seam welded along an interfacing edge. The tube material is braze cladded on both sides for corrosion resistance and for high quality internal braze bonding of (1) longitudinal tube webs for optimizing burst strength, and (2) the tubes to associated air centers which are not cladded for an economical unit. The tubes can be readily made in a multiport or single port design by roll forming the longitudinal webs in each tube, and at discreet lengths along the tube length to provide a cut off area for sizing the tube and a smooth circumferential area where the tube enters the header providing a close fit and high quality brazed joints. This tube design provides material and cost advantage over the conventional extruded tubes and is readily fabricated using corrosion resistant alloys providing long service life. The number and spacing of the webs in this construction can be readily made by changing the number and spacing of the web forming rolls.

Abstract: A pressure proof reactor vessel and the method of making such vessel wherein the vessel has a cylindrical one-piece outer wall and a cylindrical one-piece cylindrical inner liner, which liner has a smooth continuous interior surface spaced radially inwardly from the outer wall and concentric thereto. The inner cylindrical wall is formed from a one-piece material with its radial thickness being substantially less than the radial thickness of the outer cylindrical wall. Support means in the form of a spiral is positioned in said space between the cylindrical outer wall and the cylindrical inner liner defining a pathway for the flow of coolant between the outer wall and the inner wall. The support spiral is secured to the outer surface of the one-piece cylindrical inner liner prior to assembling of the inner liner to the outer cylindrical one-piece outer wall.

Abstract: A method of affixing a plurality of tubes having oval ends into a plurality of corresponding oval openings of equal circumference in the header wall of a heat exchanger. The minor diameter of the tube ends is greater than the minor diameter of the header openings and the major diameter of the tube ends is less than the major diameter of the header openings. The tube ends are inserted into corresponding openings in the header wall whereupon the minor diameter of the tube ends is reduced and the major diameter of the tube ends is increased to create a substantially fully contacting fit around the circumference with said header openings. Ends of the tubes are welded to corresponding collar openings in the header wall to form a plurality of tube-to-header joints. Flux is applied to the air-facing side of the tube-to-header joints, and molten solder is applied to the opposite liquid-facing side and flowed into any voids in the welded joints to substantially seal the joints against leakage of liquid.

Abstract: A method of producing an aluminum tube covered by a layer of zinc using a continuous cold forming machine which includes the steps of: providing an extrusion die having a heating device and an inert gas-blowing tube to the cold forming machine, introducing an aluminum prime wire to the cold forming machine, extruding the prime wire through the extrusion die to form an aluminum tube while heating the die to a high temperature and blowing an inert gas across the die toward the tube to provide a high-temperature, non-oxidized aluminum tube, and flame spraying zinc powder onto the outer non-oxidized surface of the tube to cover the surface and provide an anticorrosive layer of zinc on the aluminum tube.

Abstract: Methods for fabricating and repairing heat exchange tubing are provided including depositing an integral solderable coating onto a surface oxide of a tubular member and then soldering a plurality of spaced fins onto the integral solderable coating. The methods described herein provide economical techniques for fabricating heat exchange tubing suitable for use in extremely corrosive environments.

Abstract: A method for fabricating a composite tube for a heat exchanger includes the steps of feeding tube stock and liner stock into a tube mill, superimposing liner stock upon the tube stock and simultaneously forming the tube stock into an outer tube while forming the liner stock into a lining within the tube. The tube is then welded or brazed longitudinally and the liner is brazed to the outer tube.

Abstract: The fillet-forming ability of brazeable aluminum alloy materials, such as brazing sheet or heat exchanger components, for example fins, tubes and headers, is significantly improved by treating the material, prior to brazing, with an aqueous acid solution containing a dilute mixture of HF and HNO.sub.3. The treatment generally takes place for a period of not less than 5 seconds within the temperature range from about 15 to about 98.degree. C.

Abstract: A heat exchanger, in particular for an automotive vehicle, includes a bundle of tubes with a plurality of assemblies of first tubular elements with second tubular elements, so as to constitute a continuous circuit for circulation of fluid within the heat exchanger. One of the tubular elements has a portion which is polygonal in cross section and which is telescoped or mated with the other one of the tubular elements of the same assembly, this other tubular element being circular in cross section.

Abstract: Potential difficulties with corrosion in heat exchangers utilizing aluminum fins are avoided by using fin and tube constructions made by a method which includes the steps of providing a flattened tube (50) of ferrous material (80) and having an exterior coating (82) predominantly of aluminum; providing at least one serpentine fin (56) of aluminum (86) and clad with a predominantly aluminum braze cladding (88); assembling (102) the fin (56) to the flattened tube (50); applying (94), (100), (104), a brazing flux to at least one of the fin (56) and the tube (50); raising (106) the temperature of the assembly to a level sufficient to at least partially melt the braze cladding (88); and maintaining the temperature for a sufficient period of time to achieve a brazed joint (60) between the fin (56) and the tube (50) but a time insufficient to convert the coating (82) and the cladding (88) to ferrous-aluminum intermetallic compound or intermediate phase.

Abstract: The heat exchanger comprises a plurality of oval-shaped flat tubes for conducting refrigerant and a plurality of corrugated fins fixedly sandwiched between the flat tubes. First and second header pipes are fixedly and hermetically connected tot he flat tubes through openings formed on the header pipes and communicate with the interior of the flat tubes. The flat tubes include a pair of wedge-shaped projections at the opposite ends thereof, respectively. At least one pair of wedge-shaped projections engage with an interior surface of the header pipes adjacent to the openings when the flat tubes are received into the interior of the header pipes through the openings, thereby preventing relative sliding motion between the header pipes and the flat tubes through the openings. The wedge-shaped projection may be disposed on either the upper and lower flat surfaces or the curved side surfaces of the flat tubes.

Abstract: A method of diametrically contracting a cylindrical body, includes the steps of grasping the cylindrical body with a plurality of elongated grasping members, preparing a cylindrical drawing die having an opening at one end and a tapered inside peripheral surface, drawing the grasping members together with the cylindrical body into the drawing die, through the opening, and applying a compression force to the cylindrical body through the grasping members due to the passage along through the tapered inside peripheral surface, to thereby cause the cylindrical body to be diametrically contracted. During the drawing process, since the cylindrical body does not come into direct contact with the drawing die, neither scratches nor baking cracks are produced on the outside surface of the cylindrical body.

Abstract: A heat exchanger is described which includes a plurality of flat tubes for conducting refrigerant and a plurality of corrugated fins fixedly sandwiched between the flat tubes. The flat tubes and the corrugated fins jointly form a heat exchange region. First and second header pipes are fixedly and hermetically connected to the flat tubes and communicate with the interior of the flat tubes. The header pipes are also provided with inlet and outlet pipes for connecting the heat exchanger to other external elements of an automotive air conditioning system. The inlet and outlet pipes protrude from opposite sides of the header pipes in the direction of thickness of the heat exchanger which is perpendicular to the longitudinal axes of the flat tubes. One end of each of the inlet and outlet pipes is shaped so as to prevent interference with the ends of the flat tubes that are inserted into the interior of the header pipes.

Abstract: A condenser for use in an automobile air conditioner, which includes a pair of header pipes (1) each consisting of a tank portion (2) and an end plate (3); a plurality of parallel flat tubes (14) extending between the header pipes for supporting coolant flows; the end plate being continuously outwardly curved and joined to the tank portion such that inside surfaces of opposite joint edges (2a) of the tank portion overlap outside surfaces of opposite joint edges (3a) of the end plate, whereby the tank portion reinforces the end plate to withstand high pressures of the coolant flows. The flat tubes are brazed to the header pipes such that opposite ends of each flat tube are brought so closely to the joint edges that there is only a minimum clearance that is able to prevent brazing material from entering the flat tube, whereby the tank portion is minimized.

Abstract: A process for fabricating a PTC thermistor device. A pair of opposing electrodes are formed on either major surface of a ceramic plate PTC thermistor element. Metallic plate heat radiation fins are secured to the opposing electrodes by brazing in a non-oxidizing environment. The PTC thermistor element is then heat treated in an oxidizing environment. Optionally, the opposing electrodes may include shield layers for preventing emission of gas from the PTC thermistor element during brazing.

Abstract: A heat exchanger made of aluminum includes a tube and a fin joined thereto by a fillet which is made primarily of zinc. The tube and the fin are each prepared from a material made of aluminum and nobler than the fillet by at least 0.325 V in terms of potential. The use of the material for forming the tube and the fin prevents cracks from developing in the vicinity of the interface between the fillet and the tube or the fin.

Abstract: Method and apparatus for making a roof of a water-steam cooled cyclonic separator. The fixture locates, supports, and restrains portions of the roof during welding operations. By continuing that restraint through a stress relief step, the method and apparatus address the problem of distortion that otherwise would occur during welding. The method and fixture provide good access to the roof during the welding operations and, in particular, allow for faster welding and welds of higher quality by maximizing the availability of "down hand" welding techniques. The fixture is a universal fixture, designed to accommodate roofs of varying geometries.

Abstract: In a method for joining a plurality of heat exchanger flat tubes with headers of a heat exchanger: each of the opposite end portions of the flat tubes has a cross section provided with a major axis and a minor axis; opposite major axis side walls of the cross section of each of opposite end portions of each of the flat tubes are obliquely cut off so as to form each of opposite minor axis side walls of the cross section of the end portion of the flat tube into a trapezoidal shape; the end portion of the flat tube is passed through an elliptical hole formed in the header; the end portion of the flat tubes thus passed through the header is flared over its entire peripheral wall; the thus flared end portion of the flat tube is then bent so as to be formed into a bent portion of the flat tube, which bent portion constitutes an essential part of a joint formed between the flat tube and the header; and the thus formed joint is dipped into a molten filler metal bath to form brazed or soldered portions around the join

Abstract: The tubes of a heat exchanger core are interlocked and spaced from are another prior to brazing in a furnace. Each of the separate plates of each tube is formed with discrete laterally spaced tabs which project transversely to the plane of the plate for spacing and for locking adjacent tubes with one another. These tabs are an integral part of stamped plate and are bent so that they are generally perpendicular to the plane of the plate. The locking tabs have a flat, upturned locking end that is resilient to closely fit over the end of an adjacent plate of an adjacent tube to interlock adjacent tubes together. Straight spacer tabs are used to spaced separate tubes from one another. These spacer tabs are similar to the locking tabs but have straight abutment ends instead of the flattened locking end portions to provide column support. With the locking and spacing tabs in place, the tubes are arrayed in a core which is securely interlocked and accurately spaced.

Abstract: In a method of making a motor vehicle radiator, extruded hollow shapes of oval cross section provided inwardly with at least one longitudinally extending web lying transversely of the larger major axis of the oval cross section are reshaped, e.g. rolled, under pressure to a cross-sectional form of a flat profile tube having two parallel sides, soldered to cooling fins and fitted into a radiator housing. The extruded hollow shape is of light metal with a substantial oval cross section.

Abstract: A method and product for forming a joint between intersecting sections of tubing for the conduct of fluid flow. For forming the joints, there is included a section of primary tubing which is drilled or punched to form a radial aperture defining the location at which the joint is to be formed. To effect joinder with the primary tube, there is provided a secondary tube having an end that includes a pilot portion extending rearward from a recessed end plane and which merges with an integrally shaped saddle bead formed about the tube periphery. Inserting the pilot end of the secondary tube into the provided aperture of the primary tube enables the saddle bead to incur a contour overlay against the outside diameter of the primary tube for effecting lateral alignment therebetween while enabling joinder by welding, brazing or soldering. Also disclosed is the method of forming the secondary tube to produce a recessed end face/saddle bead combination by the use of upsetting swaging dies.

Abstract: A heat exchanger suitable for use as a condenser in an automotive air conditioning system has a pair of header tanks connected by flat extruded tubes. Air centers are sandwiched between the tubes for extracting heat from refrigerant directed through the flat extruded tubes. Each of the flat extruded tubes are located in spaced parallelism and each of the tubes have an end portion with a tapered outer surface for piloting the tube into contact with a mating tapered surface in a header opening and wherein the axial length of the end portion and the tapered surfaces are selected to define a brazed joint having maximized contact surface and strength. Each of the flat extruded tubes has a peripheral shoulder engageable either with the outboard surface of the header or with a countersunk surface portion thereof to precisely locate the end surface of each of the tube end portions with respect to avoid excessive tube stickout within the header tank volume.

Abstract: The process of manufacturing an oil cooler which comprises the steps of:(A) making cooling fins by forming a plurality of insertion holes of which inner brim is projected along the axial direction for inserting a plurality of tubes in each sheet to be transformed into cooling fins, and to drill a plurality of pores for inserting linear brazing materials at positions closed to the insertion holes, respectively,(B) inserting a plurality of tubes arranged in parallel into each of insertion holes of a number of the cooling fins respectively, and inserting linear brazing materials into the pores of each of the cooling fins, and(C) joining the brims of the cooling fins and the tubes by heating to melt said brazing materials.

Abstract: Potential difficulties with corrosion in heat exchangers utilizing aluminum fins are avoided by using fin and tube constructions made by a method which includes the steps of providing a flattened tube (50) of ferrous material (80) and having an exterior coating (82) predominantly of aluminum; providing at least one serpentine fin (56) of aluminum (86) and clad with a predominantly aluminum braze cladding (88); assembling (102) the fin (56) to the flattened tube (50); applying (94), (100), (104), brazing flux to at least one of the fin (56) and the tube (50); raising (106) the temperature of the assembly to a level sufficient to at least partially melt the braze cladding (88); and maintaining the temperature for a sufficient period of time to achieve a brazed joint (60) between the fin (56) and the tube (50) but a time insufficient to convert the coating (82) and the cladding (88) to ferrous-aluminum intermetallic compound or intermediate phase.

Abstract: Leakage of fluid from a heat exchanger and fluid mixing in the case of a two fluid compact high intensity cooling heat exchanger are prevented by diffusion bonded areas of the heat exchanger formed using small locally raised borders which extend about the fluid passage or passages of the heat exchanger to form raised contact portions that experience locally high stresses during diffusion bonding thereby insuring material flow and complete bonding. The thickness of the locally raised borders is the same as or slightly greater than the tolerance of the rolled sheet material used to form the laminates of the heat exchanger whereby local deviations in thickness of the thin laminates will not result in non-bonded areas.

Abstract: A vehicle radiator and method of manufacture comprising joining the liquid conducting tubes to the tank headers by punching holes with upstanding collars in the headers and inserting a tube end in each collar, each collar to tubing joint being formed by welding an intermediate portion of the joint and filling the rest with solder thereby forming a composite joint of weld and solder with additional solder forming a fillet behind the weld.

Abstract: An automatic braze welding apparatus comprises a divisional rotatable index drive for indexing a rotatable plate in increments of 45.degree.. A plurality of clamping devices are used for safely seating a workpiece radiator at the divisional radial positions of the rotable plate. At least one flux supplying head is mounted on a first position of the divided rotatable plate, and at least one first welding manifold provided with a plurality of torches with at least one position changeable means is mounted on the divisional second and fifth positions, respectively. At least one second welding manifold performs second welding work at the upper surface of the divisional third and sixth positions, and at least one product position correcting device corrects any unbalanced state of the product at the fourth and seventh positions, thereby clamping the radiators by means of the product clamping means and removing it therefrom.

Abstract: An actively cooled device, such as a heat shield for a fusion reactor, includes elements (10) of a heat-resistant material, particularly graphite, each being provided with at least one recess having a circular cross section, particularly a groove (14), into which a cooling pipe (16) conducting a coolant is brazed directly and with surface contact. This produces an effective dissipation of heat from the elements and a more durable connection of the elements with the cooling pipe or pipes.

Abstract: A heat exchanger core as prepared for handling and heat bonding has a pair of headers, a row of oval shaped fluid carrying tubes received at opposite ends in the headers, air centers interleaved with the tubes, oval shaped reinforcement tubes sandwiching the fluid carrying tubes and air centers, and processing straps wrapped about the core clamping the fluid carrying tubes and air centers together between the reinforcement tubes.

Abstract: A rotatable welding fixture for supporting elongated structures such as tubes while performing metal welding operations on the tubes. The fixture includes an elongated central rigid frame which is rigidly attached at each end to an end plate and a trunnion aligned with the longitudinal axis of the frame. The central frame can be conveniently formed by a plurality of adjacent tubes each having a rectangular cross-sectional shape. A plurality of elongated structures such as tubes to be metal clad welded are supportably attached to the outer longitudinal surfaces of the fixture. The tubes being welded can be advantageously cooled during welding by passing a fluid such as water through the tubes. The invention also provides a method for metal clad welding the elongated structures while being rigidly supported by the rotatable welding fixture.

Abstract: An oil cooler for motor oil used in engines has an element core, a base on which the core is placed, and a casing housing the element core. The core consists of a plurality of sets of two elements being combined together face-to-face and a fin member which is placed on the set of elements. These two elements and one fin member are join together to make a single unit. Several units are contained in the casing of the oil cooler. Cooling water circulates through the flat hollow doughnut-like elements combined. A partition is formed in the interior of the elements combined and a set of cooling water supply hole and exit hole is provided at both the sides of the partition. The core of elements and a base on which the core is placed are brazing adhered or fixed to each other in a hot vacuum furnace and then a dish-like cap is applied to the base. Motor oil to be cooled is led from the engine block to a filter mechanism through several fin members situated between elements.

Abstract: A method for brazing aluminum components with a flux, wherein the flux and the aluminum components are heated together in a brazing furnace filled with a nonoxidizing gaseous medium, thereby fluxing and brazing the aluminum components at one time, or wherein the flux is previously pulverized and electrostatically deposited on the aluminum components, and the fluxed aluminum components is heated to a brazeable temperature in the furnace, thereby melting the braze metal and effecting the braze joints between the aluminum components.

Abstract: A process of manufacturing a spacer element for spaced heat exchange tubes of a heat exchanger in which the tubes are of elliptical cross section and arranged in rows and columns. In the process a band of stranded interwoven fine wires are wound between and on the surfaces of the spaced heat exchange tubes and is fused to the tubes at the regions of contact therewith by a heating operation to form a spacer for holding the tubes in spaced relation. The heating operation can be carried out by heating the tubes and band in an oven, either in a vacuum or with a protective gas.

Abstract: A method and apparatus for uniting workpieces of silicon-infiltrated silicon carbide with large dimensions includes surrounding each of two silicon-infiltrated silicon carbide workpieces with at least one tightly closing shell in the vicinity of a junction between the workpieces, defining at least one intermediate space between the shell and the workpieces. A vacuum or an inert gas atmosphere is maintained in the intermediate space or spaces. Solder is placed at the junction and the junction is locally heated to soldering temperature for materially bonding the workpieces by soldering at the junction.

Abstract: A method of forming a heat exchanger includes brazing heat exchanger components with a flux of non-corrosive fluoride complexes. The components comprise an aluminum alloy having improved brazing characteristics and containing 0.3 to 0.8% Mg, 4.0 to 8.0% Zn, one or more of 0.05 to 0.30% Zr, 0.05 to 0.30% Mn, 0.05 to 0.30% of Cr, 0.05 to 0.30% of Cu, aluminum and unavoidable impurities.

Abstract: A method of producing a heat exchanger comprising abutting a tube made of an aluminum material and fins made of an aluminum material, applying to the resulting abutments a flux containing zinc halide, and thereafter conducting a reaction soldering in an inert gas atmosphere. The assembled tube and fins applied with the flux may be moved in a position to enhance the formation of zinc deposited by the reaction soldering during the drying step of the flux. The heat exchanger produced by this method has a thick and uniform Zn coating at the joints with good mechanical strength and surface conditions.

Abstract: A method of securing in fluid tight relation the spaced ends of straight legs of heat exchange tubes of a U-shaped matrix to a tubular fluid conveying duct is effected by bending the spaced ends of the straight legs of the matrix to reduce the spacing between the ends of the tubes, thereafter loosely gathering the ends of the tubes to bring them into contact along their surfaces and then encircling the loosely gathered tube ends with frame elements which apply compression forces to the tube ends to deform then and cause them to come into contact with one another over substantially the entire surface areas thereof. The tube ends are then heated to braze them together and unite them with the frame elements as a unified block assembly. The block assembly is then inserted into an opening of conforming shape in the tubular fluid conveying duct and joined to the duct in sealed relation.

Abstract: An end fitting for a serpentine heat exchanger couples an inlet or outlet port to a pair of flat tubes comprising the heat exchanger core. The fitting comprises three laminated plates and a nipple coupled to an opening in the outermost of the plates. The inner plate is a header plate with the slots for receiving the flat tubing. A spacer plate interconnects the outer and inner plates and has an aperture shaped to couple the port to the slots for defining a fluid flow path. The plates are stamped from aluminum sheet stock clad with a brazing alloy. The plates are assembled and secured by a steel rivet and the nipple is attached. The parts are joined by brazing. The fitting can be brazed to the exchanger core at the same time.

Abstract: A process of fixing a double-walled tubing structure to a titanium tube sheet, the tubing structure comprising a non-titanium outer tube and a titanium inner lining tube, comprising the steps of: pressure-welding a titanium collar to an end face of the outer tube to form an integral titanium end portion at one end of the outer tube; inserting the titanium lining tube in the outer tube and fixing the titanium lining tube to the outer tube in pressed contact with the inner surface of the outer tube to form the titanium-lined double-walled tubing structure; and inserting an end section of the tubing structure in a hole in the tube sheet, and welding the titanium end portion of the outer tube and an end portion of the lining tube to the tube sheet. Instead of the titanium collar being directly welded to the outer tube, an auxiliary collar made of a metal material for sound welding to the outer tube may be pressure-welded at its one end to the titanium collar, and fusion-welded at the other end to the outer tube.

Abstract: A process for producing brazeable pipes particularly for use in heat exchangers, the process comprising preparing a brazing sheet which comprises a core sheet coated with a brazing substance at least on one surface, forming a bulged portion of a semi-circular cross-section in the central section of the brazing sheet, providing apertures in the bulged portion for securing tube ends therein, and rolling the brazing sheet into a cylinder with its opposite ends being butt jointed to each other.

Abstract: A tube-type heat exchanger has two tubesheets, each provided with a multitude of bores, and tubes which extend between the tubesheets at their bores, their hollow interiors opening into the bores. Each tube at its ends is joined to the tubesheets along fillet welds which, being free from crevices, eliminate the build up of deposits and corrosion which commonly develop in the crevices of heat exchangers. To assemble the heat exchanger, each tube is passed through a bore in one of the tubesheets and advanced toward the other tubesheet, its leading end being inserted into a socket at the end of a bore in the other tubesheet. Then the leading end of the tube is welded to the tubesheet at which it is located. This leaves the trailing end of the tube in the bore of the tubesheet through which the tube was initially inserted, and that bore likewise terminates at a socket. The trailing end of the tube is machined down from within the bore until it extends no farther than the socket at the end of the bore.

Abstract: Serpentine heat exchanger tubes are formed with spaces smaller than the fins which must fit in the spaces, the tubes are elastically spread apart so that tubes can be inserted, and the tubes are then allowed to contract to grip the elements for good contact and to help maintain the assembly until a brazing operation. A machine for inserting the fins has spreader blades for insertion into the tube spaces remote from the tube bends, and including sets of blades which then are moved toward the bends to fully dilate the spaces to permit easy insertion of the fins.

Abstract: An apparatus and process for control rod assembly and construction for a nuclear reactor is disclosed wherein the control rod is of cruciform configuration having a plurality of and preferably four flat planar members. Each planar member is made up with an assembly of square cross sectioned tubular members. Each square cross sectioned tubular member includes a defined cylindrical center and a constant thickness surrounding tubular metallic shell to provide the contained neutron absorbing materials in a cylindrically shaped pressure vessel. The constant thickness surrounding tubular shell constituting the cylindrical shaped pressure vessel has four corner sections added to generate a modified square exterior profile. These added four corner sections comprise an addition to the tubular side wall thickness of the shell. Appropriate chamfers and rounding are provided to the square profile to impart both stress relief and convenient points for automated welding between side-by-side square sections.

Abstract: A plate type heat exchanger has a plurality of tube units and a plurality of corrugated fins. Each of the tube units is formed by a pair of plates, namely a pair of plates are connected to each other by a brazing material at a connecting portion at an outer periphery of the plate and a center rib at a center axis of the plate. The center rib has an enlarged portion at the top end thereof in order to gather the molten brazing material toward the enlarged portion. The brazing at the center rib is started from the enlarged portion. Therefore a brazing defect is prevented from occurring at the top end of the center rib. Since the tube unit is effectively connected by brazing, the tube unit of the present invention has enough anti-pressure strength.

Abstract: A method for manufacturing a dynamoelectric machine frame according to which heat dissipating fins made of metallic sheet bent to provide a joining portion are placed on an outer peripheral surface of a cylindrical frame main body. A laser beam is irradiated in the direction parallel to the contact surface between the portion of the heat dissipating fins to be joined on the frame main body and the outer peripheral surface of the frame main body. Thus, the laser welding of the heat dissipating fins to the frame main body is achieved without large thermal distortion of the frame main body.

Abstract: A method of manufacturing heat-exchanger excellent in the pitting corrosion resistance is disclosed, wherein, in the manufacture of aluminum heat-exchanger to be brazed under heat in the furnace of inert gas atmosphere using fluoride flux, Zn is disposed at a position of 430.degree. to 620.degree. C. in the furnace to melt and vaporize it and the vapor of Zn is allowed to contact with the fin material and the tube material coated with said flux simultaneously with the brazing under heat of these aluminum components, or the fin material coated with said flux and dried and the tube material without flux are assembled and retained for not less than 1 minute in the vapor of Zn of a temperature lower than the melting point of said flux and higher than the temperature, at which these components are heated, in the inert gas and thereafter brazing is performed at a temperature higher than the melting point of said flux.