Abstract: Apparatus for automatically loading a series of hairpin tubes into a magazine that is used to temporarily store the tubes so that they can be later laced into a fin pack. The magazine contains individual open-ended compartments for receiving and storing the tubes therein. The compartments are indexed into a loading station having a ram for driving hairpins into the indexed compartment. A gripping mechanism is also located in the loading station having fingers that engage the extended legs of the hairpin and guide the legs into the magazine compartment.

Abstract: A method and apparatus for automatically assembling hairpin tubes in the tube receiving holes of a fin pack unit. Pre-assembled fin pack units are serially moved from one station to the next to receive hairpin tubes, to have bells formed in the open ends of the laced hairpin tubes, to have expansion tools inserted upwardly through the open ends of the hairpin tubes to expand the walls of the tubes outwardly into contact against the fin plates and tube sheets with sufficient force to lock the tubes into the unit, and to have return bends interconnect the bell-like seats of adjacent hairpin tubes and thus complete the heat exchanger flow circuit.

Abstract: Apparatus for automatically loading a series of hairpin tubes into a magazine that is used to temporarily store the tubes so that they can be later laced into a fin pack. The magazine contains individual open-ended compartments for receiving and storing the tubes therein. The compartments are indexed into a loading station having a ram for driving hairpins into the indexed compartment. A gripping mechanism is also located in the loading station having fingers that engage the extended legs of the hairpin and guide the legs into the magazine compartment.

Abstract: The present invention is directed to a method and apparatus for joining aluminum members within an aluminum heat exchanger coil. A tubular member to be joined to a separate member in the coil has its exterior surface roughened by sand blasting to enhance adhesive adherence. The roughened surface is covered with a conversion coating to replace any accumulated aluminum oxide, to prevent the formation of additional aluminum oxides and to simultaneously provide a surface adapted to adhere to an adhesive. An adhesive is then applied to the mating areas of the tubular members to be joined and subsequently cured to form a tight secure joint. This invention is particularly useful in field repair of aluminum heat exchanger coils.

Abstract: A heat exchanger tube comprising a primary tubular element for carrying a heating or cooling medium and a secondary heat transfer surface spirally wound about the tubular element. The heat transfer surface is formed in a U-shaped configuration with its base being wound in metal-to-metal contact against the tube surface and the two legs thereof extending radially from the base. Each leg, in turn, is provided with a plurality of slits extending inwardly from the extreme edge thereof to create a dense population of relatively thin spine-like fins radiating from the tube. A meniscus of adhesive is formed between the legs and the surface of the tube which secures the base of the fin strip in metal-to-metal contact against the tube surface and also supports the individual spine-like fins in a radially extended position. In a further embodiment of the invention, the exposed surfaces of the primary and secondary elements are coated with a thin layer of adhesive to protect the tube from corrosion.