Abstract: Transfer molding of polypropylene, polyvinylidene fluoride, FEP fluorocarbon resin or PFA fluorocarbon resin to produce a lining for a 6" tee pipe fitting is accomplished isothermally by applying pressure of the order of 200 psi to the material while the material, the charge holding chamber and the tee mold are secured in a fixture in an oven. Transfer is performed at a stabilized resin temperature of the order of 375.degree. F. for polypropylene, 450.degree. F. for polyvinylidene fluoride, and 640.degree. F. for FEP and PFA resins over a relatively long time interval. Pressure is removed, the mold assembly is transferred to a press outside the oven, pressure of the order of 700 psi is reapplied to the material, and the mold is force cooled progressively from a remote point back toward the gate which is located in the fitting opposite the stack section thereof.

Abstract: A heat exchanger element is provided with small-bore copper tubing jacketed with perfluoroalkoxy resin wherein the ends of the jacketed copper tubing are each telescoped over the end of a stainless steel nipple having a raised shoulder at its end and an annular groove adjacent thereto. A stainless steel ferrule surrounding a sleeve of polytetrafluoroethylene overlies the joint and for a short distance to either side and is contracted particularly in the region of said nipple groove to squeeze the copper tubing thereinto behind said shoulder. This interlocks the tube with the nipple and establishes a fluid-tight seal between the ferrule, the nipple and the metal tube. The nipples are joined to headers or manifolds by welding or in similar manner.

Abstract: A fluid conduit assembly is provided having at least two snug-fitting concentric pipes each of which is independently impervious to fluid. End fittings are secured to each end of the conduit and have separate portions joined, respectively, to a different one of both of the pipes with a separate fluid tight seal therebetween. The outer pipe is metallic while the inner pipe is non-metallic.

Abstract: An end fitting for metal tubing having a bore provided with spaced annular grooves is also provided with a thin hard metal tubular insert which is disposed within the end of the tubing when the tubing is introduced into the bore and extends from the inner extremity of the metal tube to a point beyond the last annular groove. At least a portion of the insert is expanded radially along with the overlying section of the tubing forcing the latter into said grooves. The insert may have an unexpanded end portion which makes at least a snug fit within the unexpanded tube. The result is substantially increased flex life of the metal tube.

Abstract: A disconnectable union for fluid piping is provided in which a pre-load dependent first seal between disassemblable union members is coaxially related to a second seal operable independently of the pre-loading of the first seal such that the second seal independently contains any fluid that comes in contact with it even if such fluid contact is due to diminution of the pre-loading of the first seal. Various flange joint configurations and seal constructions are disclosed for both plastic lined and unlined metal pipe.

Abstract: A structure having at least two joined contiguous parts, of which at least one is straight and of uniform girth throughout its length, is jacketed with a given fluorocarbon resin by first cross feed extruding a jacket of said resin onto said one part, next providing a joint between said one part and another part, and thereafter coating at least said joint, any exposed surfaces of said one part present between said joint and the adjacent end of said jacket, and a narrow circumferential band at said adjacent end of said jacket with said given resin by spraying in dry powder form, and then applying heat to fuse said sprayed on resin. A heat exchanger is described where the exchanger tubes constitute the straight parts and the manifolds to which they are brazed the other parts.

Abstract: A method is described whereby perfluoroalkoxy (PFA) fluorocarbon resin is fusion bonded to polytetrafluoroethylene (PTFE) resin to provide united sections thereof and to provide a bonded or welded interconnection between separate sections of PTFE resin. The welds are obtained under minimal positive pressure, generally below about 40 psi, at a temperature above the gel point of the PTFE resin, generally between 635.degree. F. and 710.degree. F., with subsequent slow cooling under pressures somewhat higher and generally ranging between about 59 psi and 150 psi.

Abstract: An expansion joint having a working element of polytetrafluoroethylene is protected from fire by jacketing with an enclosure of refractory material. The jacket has openings through which pipe passes to and from the joint. A gland is inserted within the openings around the pipe for closing most of the gap therebetween while affording sufficient freedom of movement not to interfere with motion of the joint. Each gland is formed from a metal ring, channel shaped, coated on all surfaces with an intumescent material which expands in a fire to seal all remaining gaps between the pipe and the encircling opening in the jacket whereby hot gases are barred from passage. Alternatively, where radial movement is not required, the intumescent material may be coated directly on the refractory material around the opening surrounding the pipe.

Abstract: Steel pipe, fittings, joints and valves, lined with PTFE resin are rendered fire-safe for in excess of one hour exposure to open flames by jacketing the components with an enclosure formed from fibrous refractory material. The enclosures are configured and dimensioned to contain a substantially fixed air volume within a predetermined air gap space between the exterior of the component and the interior of the jacket. As an example, high-alumina ceramic fiber mixed with a suitable binder is vacuum formed and then surface coated with an epoxy enamel to produce segments which can be joined around the components to produce satisfactory enclosures. The described segments are reinforced with a metallic skeletal structure which is located so as to permit sizing of openings in the field to accommodate alternative modes of installation.