Folded Pipe Systems
Folded Liner Pipe Systems offer a close fit final liner similar to that found with Concentric Pipe Reduction Systems but the installation operation is different. The external diameter of the liner pipe must be manufactured to the same internal diameter of the host pipe being lined.
With folded pipe liners instead of reducing the liner pipe diameter across the whole pipe, the liner is folded into a ‘C’ or ‘U’ shape and held in this shape normally with straps to a size that will allow it to be pulled or pushed through the host pipe.
Once the liner pipe is installed throughout the host pipe length being lined, air, water, or steam pressure is applied to inside of the liner to cause the holding straps to break and to revert the liner to its original shape and diameter. There are three options of folded liner including Cold Factory Folded, Hot Factory Folded and Site Folded. Both ‘factory folded options are delivered to site pre-folded as the name suggests and to the length of liner required and furthermore the process of factory folding is described by the name. Hot folded pipes do not require straps to retain the folded shape but once in place heat is required to revert them to a circular shape. Site folded liners are delivered to site as normal round plastic pipe which is butt fusion welded to the required length. The round pipe is then Pulled/Pushed through a die on site to create the required fold. Holding straps are placed on the liner and it is usually then Pulled/Pushed directly into the host pipe as a single operation.