Techniques for coating pipes

摘要

A thermoplastics injection moulding process coats a field joint of a pipeline by positioning a mould tool around the field joint to define a mould cavity. Thermoplastics material injected into the mould cavity forms a field joint coating that will set in the mould cavity. As the thermoplastics material shrinks in the mould cavity while the field joint coating sets, compacting pressure is applied radially inwardly within the mould cavity against a radially outer side of the field joint coating. A compacting fluid introduced into the mould cavity between the mould tool and the field joint coating may be used to apply pressure against the field joint coating. This accelerates and controls cooling of the field joint coating while maximising quality.