Cured-In-Place pipe lining is a trenchless technology rehabilitation method used to fully restore damaged pipes suffering from cracks, protruding roots, scale buildup and other obstacles hindering optimal flow capacity. Cured-In-Place pipe lining creates a pipe within a pipe and is free of seams and joints. Prior to the installation of Cured-In-Place pipe lining, failures within the pipe are located using CCTV and Inspection work. Higher pressure jetters are then used to clean and prep the pipe for Cured-In-Place pipe installation.
Cured-In-Place Pipe Lining Installation:
A pre-measured, flexible liner is placed in a roller assembly using vacuum assist to saturate the liner with resin or alternatively, resin is poured into the liner and a weighted (pinch) roller is used to saturate every inch of the liner. The liner is then closed at one end and attached to a pullback rope and rolled into an inversion tank. The lead end of the liner is pulled out of the inversion tank and is folded back and held in place with an air tight seal at the inverter drum nozzle to start the inversion. Air pressure is used to invert the liner into the existing pipe forcing it to take shape of the host pipe even at differences in diameter along the length of the pipe. The inter-compression tube is then deflated and removed. Once the CIPP liner has been installed, the liner is set to cure.
Types of Cured-In-Place Pipe Lining Cure:
Hot Water Cure
Hot water cure was the original method used to cure CIPP lining. This curing process consists of circulating hot water from the hot water boiler, through the new CIPP liner to the access points. The continuous circulation of hot water occurs until the resin liner is fully cured. Cold water is then flushed throughout the pipeline in order to cool the liner and prepare the pipe to be returned to service.
Similar to Hot Water Cure, the Steam Cure process involves circulation of steam through the pipe at a hot enough temperature to cure the CIPP liner saturated in resin. Boilers are used to create the steam which is then introduced into the pipe from one end using pressurized air. The heat transfer from the steam then cures the resin soaked CIPP liner. Finally, cool air is pushed through the pipe and the fully rehabilitated pipe is ready for use.
Emerging as a preferred CIPP curing method, UV Cure begins with inserting an UV light train and CCTV system into the pipe. The light train is activated and at a controlled speed, pulled back through the pipe to cure the liner. Speed of the light train depends on the pipe diameter and project specifications. Air pressure, cure rate and temperature are all measured and monitored throughout the entire process.
Finally, a robotic cutter is inserted into the pipeline and used to reinstate laterals or other necessary pipe openings.