Abstract: An in-line, continuous, roll-forming tube mill production line. The line includes a supply station for continuously supplying steel strip, a roll-forming station for forming the strip into a tubular configuration, and a welding station for joining by welding the edges of the strip. The line also has at least one station for performing a process which calls for the application of a liquid to the exterior of the tubing such as cleaning, rinsing or applying a coating. A preheating station is provided for preheating of the tubing by induction and a powder coating station applies a plastic coating or a metallically pigmented plastic coating to the exterior of the tubing, the powder coating station having a chamber and means for selectively isolating the tubing from chamber. Finally, the tube mill production line includes a heating station for baking and/or curing of the powder coating.

Abstract: An impeder for use in a mill for roll-forming tubing. The mill includes a feed station for supplying an elongated steel strip in flat form and a station where the strip is transversely bent from its planar condition causing the lateral edges of the strip to be brought together in abutting relationship. An induction coil is positioned about the bent portion of the strip for inducing current flow through the location where the lateral edges first abut to heat the lateral edges to plasticity. The mill also includes a weld rolls station where the plastisized lateral edges are firmly pushed together to complete welding of the tube. The impeder is disposed inside the induction coil adjacent the location where the lateral strip edges are first brought into abutting relationship. The impeder includes an outer shell made of a strong, heat-resistant material, a core disposed inside a shell and formed by an aggregation of ferromagnetic material, and components for causing passage of a coolant through the core material.

Abstract: A conduit coupling assembly for connecting the end portions of two lengths of conduit in coaxial, abutting relationship. The coupling assembly includes an abutment ring, an outer coupling, retainer means and resilient means. The ring has an internal thread sized for threading onto the end portion of one of the lengths of conduit. The coupling has a first end and a second end with a bore extending therebetween sized to slidably, rotatably receive the abutment ring. The coupling first end has an inside dimension smaller than an outside dimension of the ring so that the ring is unable to move past the first end, and the first end is provided with an internal thread sized for threading onto the ends of the lengths of conduit. The retainer means is carried by the outer coupling adjacent its second end for preventing escape of the ring from the bore.

Abstract: Apparatus is provided for the continuous production of tubing from steel strip. The formed tubing is continuously advanced along a straight-line path through polishing and buffing units to provide a smooth lustrous finish to the tubing, and through a coating chamber in which the tubing is coated with a polymer coating to prevent tarnishing of the lustrous polished surface. The finished tubing has a surface which is suitble for decorative applications such as furniture or the like.