Pipe coating method

Abstract

Abstract A METHOD OF ENVELOPING AN ELONGATED JOINT OF PIPE WITH A PROTECTIVE COATING. THE PIPE IS MAINTAINED AT APPROXIMATELY THE TEMPERATURE OF THE AMBIENT AIR PRIOR TO EXTRUSION OF AN ADHESIVE LAYER TO THE PIPE SURFACE. SINCE THE PIPE IS NOT PREHEATED PRIOR TO APPLICATION OF THE ADHESIVE THE QUANTITY OF HEAT TO BE REMOVED DURING THE COOLING PROCESS IS SUBSTANTIALLY REDUCED. THE PIPW IS SIMULTANEOUSLY ROTATED ABOUT ITS AXIS AND ADVANCED LONGITUDINALLY TO EFFECTIVELY WRAP A SHEET OF EXTRUDED ADHESIVE AROUND THE PIPE IN A SPIRAL MANNER. THE PROTECTIVE OUTER LAYER OF THE COATING, WHICH IS A THERMOPLASTIC RESIN, IS EXTRUDED ONTO THE ADHESIVE IMMEDIATELY AFTER THE LATTER HAS BEEN APPLIED TO ASSUER BONDING BETWEEN THE HOT EXTRUDATES OF ADHESIVE AND RESIN. THE SHEET OF THERMOPLASTIC RESIN EXTRUDATE IS CAREFULLY CONTROLLED TO ASSURE IT DOES NOT BE COME ELONGATED. THIS MINIMIZES ANY COOLING WHICH WOULD CAUSE STRESSES IN THE FINAL COATING. THE RATE OF ADVANCEMENT OF THE PIPE SURFACE AWAY FROM THE EXTRUDED RESINOUS SHEET IS ALSO CONTROLLED TO NOT EXCEED 5% GREATER THAN THE LINEAR RATE OF ADVANCEMENT OF THE EXTRUDATE. THIS FURTHER PREVENTS STRESSES FROM BEING BUILT INTO THE COATING. THE LONGITUDINAL RATE OF ADVANCEMENT OF THE PIPE IS CONTROLLED TO ASURE THAT IT WILL ALWAYS BE A FRACTIONAL MULTIPLE OF THE WIDTH OF THE SHEETS OF ADHESIVE AND RESIN, THUS RESULTING IN THE PLACEMENT OF MULTIPLE PLIES OF BOTH RESIN AND ADHESIVE. D R A W I N G

Inventors

• 👤 R Hielema

Bibliographic Details