Abstract: Plastic tubing of extruded polybutylene and the like has an end reformed into a structural bulb sealing surface which includes a stop flange permitting the tube to be drawn into sealing engagement with a mating part. The tube end is reformed in a press or jig which includes two molds, with the tube end projecting through one mold and toward the other. The other mold is normally chilled or cooled but includes an I.D. mandrel or pin projecting therefrom. The pin is insulated from the other mold. The pin may be heated and/or cooled during the reforming cycle of the process to enable uniform heating of the projecting tube end from both the inside (I.D.) and outside (O.D.) of the tube end. The process and apparatus of the invention provides a more uniform and integral reformed tube end. The cycle time of the process may also be reduced resulting in greater productivity with less energy consumption.

Abstract: Plastic tubing of extruded polybutylene and the like has an end reformed into a structural bulb sealing surface which includes a stop flange permitting the tube to be drawn into sealing engagement with a mating part. The tube end is reformed in a press or jig which includes two molds, with the tube end projecting through one mold and toward the other. The other mold is normally chilled or cooled but includes an I.D. mandrel or pin projecting therefrom. The pin is insulated from the other mold. The pin may be heated and/or cooled during the reforming cycle of the process to enable uniform heating of the projecting tube end from both the inside (I.D.) and outside (O.D.) of the tube end. The process and apparatus of the invention provides a more uniform and integral reformed tube end. The cycle time of the process may also be reduced resulting in greater productivity with less energy consumption.

Abstract: Plastic tubing of extruded polybutylene is provided with an integrally formed end cap or bulb to facilitate the joining of the tube to fixtures, unions, couplings or the like. The end cap or bulb is formed from the tube wall to form a structural bulb and sealing surface which includes a stop flange providing a shoulder permitting the tube and the sealing surface to be drawn into sealing engagement with a mating part. The structural bulb and sealing surface is formed from the wall of the tube in a special two part jig which includes male and female dies. The tube is inserted through the female die to extend a predetermined distance therefrom and the projecting portion of the tube is heated. While the tube is held against axial movement, the dies are brought together to form the structural bulb and sealing surface from the tube wall.