Patent ID: 8857700
Filing Date: 2014-10-14
Classification: B29C,F16L,Y10T

Abstract:
1. A method for forming a field joint between two insulated pipe sections, the method comprising: (a) providing a first insulated pipe section and a second insulated pipe section, wherein each of the insulated pipe sections comprises: (b) welding the steel pipe of the first insulated pipe section to the steel pipe of the second insulated pipe section, so as to form a circumferential weld joint between the annular connection surfaces of the steel pipes, and so as to form a continuous joint area which includes the circumferential weld joint and the bare end portions of the insulated pipe sections; (c) applying a layer of liquid epoxy to the joint area, and to the exposed end portions of the FBE layers, such that the liquid epoxy layer is in direct contact with the exposed end portion of the FBE layer of both of the insulated pipe sections, while avoiding substantial overlap with the terminal end of the pipe insulation layer; (d) partially curing the liquid epoxy layer by heating the liquid epoxy layer, wherein a temperature of the steel pipe and the FBE layer are maintained at a temperature below the glass transition temperature; (e) applying a layer of an adhesive over the liquid epoxy layer and in contact therewith; (f) preheating the chamfer of each pipe insulation layer to a temperature within the range of about 140-200 degrees Celsius for a time period of about 2-3 minutes; (g) simultaneously with the preheating of the chamfers, preheating the joint area for a time period of about 1-2 minutes to a temperature within a range of about 100-160 degrees Celsius, measured at an outer surface of the adhesive layer, wherein the preheating of the joint area is performed so as to maintain the temperature of the steel pipe and the temperature of the FBE layer below the glass transition temperature, and wherein the preheating of the joint area is begun about 1 minute after the preheating of the chamfers; and (h) applying a continuous layer of joint insulation over the preheated joint area and the preheated chamfers, wherein the layer of joint insulation is in contact with the adhesive layer and overlaps with the terminal end of the pipe insulation layer of both the first and the second insulated pipe sections.