The transportation of cold and hot water at temperatures for local and district heating, as well as the water transportation at power plants, chemical plants and refineries, the heating and cooling systems of industrial plants have witnessed the increase in the use of GRE piping systems that are especially suitable for the construction of extremely reliable, high performance, maintenance free pipelines.
VEM has contributed to this sector by designing the equipment for the production of thermally cured glass-reinforced epoxy pipes thermally insulated with a polyurethane foam coating and reinforced with a PE top coat. The technology regards innovative Lamellar mandrel machine with a simultaneous helical winding of cross layers of the pipe. The pipes manufactured according to this technology are characterized by a hydrolysis/alkaline acid resistant liner and a biaxial structure. The wound and on-line cured pipes are then thermally insulated with sprayed closed cell polyurethane foam and covered with PE online.
The polyurethane foam is one of the most popular insulates used in the heating systems. Integrated in the continuous filament winding process it corresponds to EN 253 standard for PU insulated pipes.
PU foaming is performed immediately after the curing, the pipes are insulated on-line with a polyurethane foam layer, which thickness is calculated on the basis of the pipe diameter and insulating efficiency. The PU layer is protected with an external polyethylene coat in order to protect the polyurethane layer during transportation and installation, as well as from the degradation due to sunlight and humidity exposure.
The foaming system is fully integrated into the process of the continuous production of pipes. Polyurethane formulation is sprayed on the surface of a cooled after curing rotating pipe thus forming a hardening polyurethane mantle. At the end of the operation the insulating layer is hard enough to allow the application of a protective layer.
No insulation voids
Consistent density of the insulate
Consistent compressive strength
Consistent thermal conductivity
Jacket fully bonded to the insulation
Fully concentric application onto the pipe