Abstract: A storage tank for a volatile inflammable liquid is provided with an attachment fitting to which an elbow assembly can be attached to support a tapping machine. If the tank primary vessel fails, liquid retained by a secondary containment vessel can be drained out by using the tapping machine to make a hole through the attachment fitting and vessel walls. The attachment fitting is installed, when the tank is built, without impairing the integrity of the primary or secondary vessel walls or providing a hole therein.

Abstract: A metallurgical vessel having a crucible supported by a trunnion having opposing axially aligned pins on which the vessel can rotate. At least one pin has a self-holding inward taper and fits in a tapered hole in the trunnion with an interference fit. The tapered pin can be inserted in the hole and be removed much easier than a cylindrical pin in a mating hole.

Abstract: A multiport piggable fluid-swivel comprising a first member having a first face, a second member having a second face adjoining and mating with the first face of the first member, the first face and the second face being positioned to rotate relative to each other about a common axis, a fluid conduit defined by a first raceway in the first face and a second raceway in the second face opposite the first raceway, an inlet conduit communicating with the fluid conduit and directed thereto at an angle so as to permit a pipeline pig to travel from the inlet conduit to the fluid conduit, an outlet conduit communicating with the fluid conduit, and a pipeline pig guide means extending from the fluid conduit to the outlet conduit to direct a pipeline pig from the fluid conduit to the outlet conduit.