Abstract: A vestibule for part entry or exit from a flow through type of braze furnace in which no substantial physical barrier is necessary to prevent air exchange between the vestibule and the outside. A controller burner within the vestibule continually burns oxygen that does leak in, sensing whether combustion is complete trough the use of an analyzer in an exhaust stack. In addition, a neutral gas injector within the vestibule chamber maintains a near net zero pressure balance in order to minimize, though not prevent, ingress leakage. Parts can therefore enter the door freely without dragging through the impediment of a physical barrier.

Abstract: A high capacity condenser for automotive application is built up from two layers or modules so as to make maximum use of standard components. The tanks of header tank and tube type condensers are extruded with interfitting clearance notches and stand-off flanges along the length of the tanks that maintain the two modules spaced apart and aligned. A specially designed cross-over pipe interconnects the two modules in a fluid sense and also cooperates in mechanically joining the two.

Abstract: A braze furnace of the inert gas type cooperatively uses the waste heat from the cooling chamber to vaporize liquid inert gas, while using the coolness of the inert gas being vaporized to accelerate the cooling process itself. The walls of the cooling chamber provide a hollow plenum into which stored liquified inert gas is metered and vaporized. From the plenum, vaporized gas is routed wherever needed to purge oxygen from the system. In addition, liquid gas can be injected directly into the cooling chamber for even quicker, direct part cooling and the purge the cooling chamber.

Abstract: A muffle furnace assembly for brazing aluminum heat exchanger workparts comprises a tubular muffle having a workpart conveyer extending therethrough. A pair of fans disposed inside the muffle circulate high temperature atmosphere through the workparts. The muffle is surrounded by an insulative outer shell spaced to form an interstitial cavity therebetween. High temperature combustion gasses are directed into the interstitial cavity and flow in a helical path about the muffle. Louvers are provided in the muffle, between the workparts and the fans, for regulating the amount of inert gas flow within the muffle. Inlet and exit vestibules usher workparts into and out of the furnace assembly to minimize oxygen contamination within the muffle.

Abstract: The brazing process for an aluminum headered condenser is improved by adding a flux drying and preheating process that both dries the wet flux layer and prepares the part for more efficient brazing. An oven is divided into two directly connected zones, one that dries the flux layer at a lower temperature, and one that preheats the condenser at a higher temperature that is still too low to melt the flux layer. Both the tanks and the core of the condenser are heated hotter than they would be if they were only flux dried, although the core is heated significantly more. The preheated parts are then transported to the braze furnace indirectly, through ambient, which serves to cool the core more than the tanks, to a temperature lower than the tanks. Finally, the part is run through a normal braze cycle. Because the tanks begin hotter than normal, they reach braze melt temperature sooner than they normally would.

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 intent 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 interstitial cavity therebetween. The inner shell includes a plurality of expansion strips having generally ellipsoidal corner expansion joints.

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: 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 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 intent 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 method of painting an object and subsequently drying such painted object by first heating a solvent-containing paint to a temperature between 80.degree. to 115.degree. F. and heating the object to be painted to a temperature between 110.degree. to 160.degree. F. such that the drying time required for the paint after painting is substantially reduced.