GB1176418A - Spray Foam Insulated Pipe - Google Patents

Abstract

1,176,418. Insulating pipes; pipe Joints. ESSO RESEARCH & ENG. CO. 1 May, 1967, No. 20015/67. Headings F2G and F2P. In a method of applying foam plastics, e.g. polyurethane; insulation 32 to a pipe section, the constituents of a foamable plastics material is sprayed on to the cleaned exterior of the pipe section, and a vapour barrier coating 12 of bitumastic material is applied prior to foaming of said constituents being completed to provide a denser plastics surface skin layer. The pipe section 10 passes through a cleaning station 14 and a heater 16 prior to passing through a foam-plastics spray chamber 20 applying the foamable plastics to the rotating pipe section. The pipe section is then advanced to a twostage bitumastic spray unit applying a mastic primer layer and a denser layer to the applied foamed plastics layer whilst the latter is still tacky to produce a thickening of the insulation skin. The pipe section is then wrapped with Kraft paper at winding station 28. A control arrangement 30, which may include mechanical, optical or electrical sensing devices for determining the position of the pipe section ends, is effective to stop and start the application of the foam insulation, bitumastic and paper winding at appropriate points adjacent the ends of the pipe section to leave pared ends, which are then butt-welded at 38 to adjacent insulated pipe sections, The bared welded joint may then be insulated. A sheet 42 of galvanized iron is cylindrically wrapped around the joint on the ends of the sprayed insulation layers 32, which terminate in convex rounded end portions 40, and is secured by metal straps 44. Foamable liquid polyurethane 48 is then poured into the void to fill the same. A suitable waterproof mastic is then applied to the insulated joint, the wrapped iron sheet 42 being left in position or removed prior to the mastic application. Adjacent pipe sections may be temporarily joined prior to passing through the various method steps by a coupling 50, Fig. 3 (not shown), comprising interengageable tubes 52, 54, each tube carrying at one end a resilient disc 60 between a fixed plate 58 and an axially movable plate 64 insertable into the end of the associated pipe section. The said end of each tube is inserted into the associated pipe section and the resilient disc expanded into clamping contact with the pipe wall by axial compression between the plates 64, 58, plate 64 being moved towards plate 58 on rotation of a threaded bolt 62. The free end of tube 52 is then slid into the tube 54 and connected thereto by a bayonet connection 68, 70.