If you need a static pipe-bursting system with lots of pull, check out the new Grundoburst 2500G from TT Technologies. The machine is rated at 625,000 pounds of pulling force, and it is designed to open up existing steel and ductile-iron pipe from 24 to 48 inches in diameter. And, as the Grundoburst system slits open and expands the old pipe, it pulls in new HDPE pipe with minimal disruption of the surface above.
During the static-bursting process, specially designed bladed cutting rollers are pulled through the existing line by the hydraulically powered Grundoburst unit, which is positioned in a small excavation on-grade with the existing pipe. As the cutting tool is pulled through, the "host" pipe is split, and a trailing expander forces pipe fragments into the surrounding soil to create an unimpeded space for the new pipe.
The Grundoburst system uses QuickLock rods, which, instead of using threaded connections, simply latch together. The rods, with the help of a flexible guide rod at the tip, are first pushed through the length of existing pipe to be replaced. A small excavation ("launch pit") allows the guide rod to surface, where it is replaced by the cutting tool and expander, which is securely fastened to the new pipe. This entire assembly is then pulled back through the host pipe.
The advantages of the QuickLock rod system, says TT Technologies, include a fast, secure, flexible, non-lubricated connection that has self-aligning capability. The rod system has a reasonably tight bend radius that facilitates the replacement of pipe installed along an irregular path.
Installing new pipe that is larger in diameter than the host pipe (upsizing) is easier when the old pipe is steel, says the manufacturer, because steel pipe splits smoothly, while ductile-iron pipe shatters and reduces the potential for upsizing.