Patent ID: 7476055
Filing Date: 2009-01-13
Classification: B29C,F16L,Y10T

Abstract:
1. A method of lining an underground conduit while the conduit is in service carrying a liquid, the method comprising the steps of: positioning a pipe winding apparatus within an access pit adjoining the conduit to be relined, the pipe winding apparatus having an annular cage through which the liquid flows; feeding the pipe winding apparatus an elongate plastic or plastic composite strip down into the pit, the strip having parallel spaced apart first and second edges; driving the strip downwards into the annular cage so as to present an incoming first edge to an adjacent second edge of a wound convolution of the strip; preventing liquid that has adhered to and ascended with the second edge from descending down towards the incoming first edge; applying a molten bead of plastic to at least one of the incoming first edge and the adjacent second edge of the newly wound pipe; and compressing the bead between the incoming first edge and the adjacent second edge, thereby forming an elongate continuously welded pipe in situ.