Abstract: A method for treating heat exchanger tubing to be expanded by fluidic or electromagnetic expansion. The tubing treatment reduces the increased material hardness of the tubing in areas where cold work has been imparted thereon. By reducing these areas which have increased material hardness, the tubing will have a substantially similar tube yield along its entire length and can therefore be expanded to substantially the same cross-sectional area throughout by either fluidic or electromagnetic expansion. After forming the cold work regions, the regions are annealed with a heat source, such as through flame or induction heating, and are gradually cooled to avoid the effects of quenching.

Abstract: A method of manufacturing a heat exchanger using fluidic expansion, the heat exchanger having tubing sections interconnected to form at least one circuit for transporting a first heat transfer fluid and conductive fins secured to the circuit for increasing the surface area thereof and increasing the heat transfer between the first fluid and a second fluid flowing among the fins. The tubing sections are positioned in a predetermined manner and the fins are disposed therewith and along the length thereof. The inlets and outlets of the tubing sections are then interconnected to form said the fluid circuit. Next, the fins are secured in place so as not become damaged during the sealing of the interconnections, which follows immediately thereafter. Finally, the entire circuit is expanded to enmesh said fins by enclosing the volume of the circuit and introducing an expansion fluid therein at a pressure which surpasses the tube yield strength of the tubing and causes the walls thereof to expand radially outward.

Abstract: An apparatus for expanding the tubes in a heat exchanger of the plate fin and tube type. The expander is of the type that expands the tubes by driving an expansion "bullet," attached to and driven by an expander or bullet rod, through the tube. The expander rod in turn is driven by a ram. The expander has a rod support apparatus that prevents the expander rod from buckling under compressive stress. The axes of movement of the ram and the expander rod are offset with the ram imparting its force to the rod through a connector link. A rod support member has a passage to support the expander rod, a passage to allow the ram to pass through the support member and a slotted passage, to allow the connector link to pass through the support member, joining the rod support passage and the ram passage. The rod support apparatus restrains the expander rod from buckling while requiring no increase in the overall length of the tube expander.

Abstract: A method for gripping a tube end of a plate fin heat exchanger by a pair of coacting jaw grippers movable both longitudinally and radially with respect to said tube end. The coacting jaw grippers are positioned such that the tube ends of a multirow coil can be gripped along any row of the coil.

Abstract: A method for controlling, in the manufacture of plate fin and tube heat exchangers, the operation of a tube expander of the type that does not expand all hairpin tubes in a heat exchanger simultaneously so that the two legs of each hairpin tube are expanded at the same time. In a preferred embodiment, a supply of pressurized air is directed through one of a selected group of open ended tube legs. Pressure sensors located at the ends other legs within the group detect the tube, if any, at which there an increase in pressure, establishing continuity between that leg and the first leg and thus identifying the two legs under test as parts of the same hairpin. This matched pair of legs is identified for expansion on the same expansion stroke of the expander. Other legs within the group between which there is pressure continuity are similarly detected and identified.

Abstract: An apparatus for gauging the height and outer diameter of a collar in a heat exchanger plate fin. The apparatus comprises a vertically displaceable carriage overhanging a base on which a plate fin can be mounted for measurement. On the carriage are mounted two displacement indicators, in the preferred embodiment electrical linear gauges. One indicator is oriented so that its indicator probe measures vertical displacement and, through the configuration of the apparatus, produces an output that can be translated to a measure of the height of the fin collar. The other indicator is oriented so that its indicator probe measures horizontal displacement. The independent but concerted positioning of two measuring blades to contact diametrically opposite points on the fin collar is resolved into an output from the horizontal indicator that can be translated into a measure of the outer diameter of the fin collar. In a preferred embodiment, the outputs of the two indicators are read on electrical digital readouts.

Abstract: An apparatus for gripping a tube end of a plate fin heat exchanger by a pair of coacting jaw grippers movable both longitudinally and radially with respect to the tube end. The coacting jaw grippers are positioned such that the tube ends of a multirow coil can be gripped along any row of the coil.

Abstract: A method and apparatus for expanding copper and aluminum tubes in either compression expansion or tension expansion which is adjustable to expand different configurations of coils on row at a time.

Abstract: A method for tension expanding a plate fin heat exchanger to provide a heat exchanger with bells of the same form and dimension and then expanding the tube into contact with the tube sheets and hairpin tubes while the bells are clamped to prevent the hairpin tubes from moving.

Abstract: A single-station tube expander apparatus bells and expands the open ends of heat exchanger hairpin tubes in a plate-fin heat exchanger unit. A frame supports belling jaw fingers which close over and the open ends of the tubes so that a belling device can enter the tube ends to urge the tube outward into a profile surface formed in the mating faces of the fingers. Also on the frame are mounted expander jaw fingers which close over tube ends which have been belled previously, and hold the associated hairpin tubes against axial movement while expander rods pass into the associated tube legs to urge the hairpin tube legs outward to contact against the fin plates and tube sheets of the fin pack heat exchanger. The belling fingers and belling device move step by step from one tube to another, and the expander gripping fingers and expander rods follow the belling fingers and belling device.

Abstract: A two stage impact beller has a rod driven pinch bullet that pre expands an end of a heat exchanger tube, and a belling tool which follows the pinch bullet. This die is generally bell shaped with a flared out proximal end. A jaw assembly holds the tube during a belling process.

Abstract: A method and apparatus for belling and expanding the tubes of a plate fin heat exchanger that involves a gripper for gripping the tube during the belling operation and a clamp for clamping a tube sheet during the tension expanding operation.

Abstract: An apparatus for tension expanding a plate fin heat exchanger to provide a heat exchanger with bells of the same form and dimension and then expanding the tube into contact with the tube sheets and hairpin tubes while the bells are clamped to prevent the hairpin tubes from moving.

Abstract: A method and apparatus for belling and expanding the tubes of a plate fin heat exchanger that involves a gripper for gripping the tube during the belling operation and a clamp for clamping a tube sheet during the tension expanding operation.

Abstract: A method and apparatus for supporting a partially formed plate fin heat exchanger at a tension expansion station and for moving the heat exchanger into and out of the expander station.

Abstract: A method and apparatus for expanding in compression a portion of a plate fin heat exchanger up to a tube sheet and then gripping the expanded portion of the tube end to expand the remainder of the tube in tension and then unclamping and belling the end of the tube at a single station.

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: A pressure differential gage and a method for detecting the presence of noncondensible gases in a refrigeration system. The pressure differential gage comprises a housing, a diaphragm, first and second tubes, a reference fluid, and indicator means. The diaphragm separates the housing into first and second chambers. The first tube has one end in fluid communication with the first chamber and a second end open to receive a sample vapor, which determines the pressure in the first chamber. The second tube has one end in fluid communication with the second chamber and a closed second end. The reference fluid is located in the second tube and determines the pressure in the second chamber. The indicator means is actuated by the diaphragm to indicate when the pressure in the first chamber differs from the pressure in the second chamber.