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US 10,047,892 B2Granted
Electrofusion fitting methods
AssigneePioneer Lining Technology Limited
InventorStephen Barnes
Life of this patent
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AssigneePioneer Lining Technology Limited
InventorStephen Barnes
Estimating the term…
The invention provides improvements to electrofusion fitting methods that allow for continuity and repeatability of welds between an electrofusion fitting and a pipe lining (or stand-alone pipe). An electrofusion fitting for joining sections of lined pipe has heating elements configured to create at least one weld between the electrofusion fitting and a pipe lining, however prior to the weld step taking place the electrofusion fitting is heated and expands accordingly to ensure contact with the pipe lining. Preheating the electrofusion fitting also provides a predetermined starting temperature for the fitting and the lining which results in improved fusion cycle reliability. Furthermore, the need for clamps or support frames to support the electrofusion fitting in situ is removed, with corresponding reductions in cycle times, complexity, and hence cost.
A method of compensating for misalignment between two plastic pipe linings comprised in host pipes during a welding process, the method comprising inserting an electrofusion fitting into corresponding recesses in the ends of the plastic pipe linings, aligning the host pipes relative to one another, and heating corresponding portions of the electrofusion fitting to a first temperature lower than a melting point of the material of the electrofusion fitting, while the host pipes are held in place, to cause the portions of the electrofusion fitting to expand to fill the recesses, wherein the electrofusion fitting, once expanded, retains and supports itself during welding to the pipe linings.
Dependencies are inferred from the claim text.