Trenchless technology for the replacement of underground pipe is not new, and the standard equipment and methods generally used are well known. This standard equipment for this technology is very large, heavy, and therefore requires additional large, heavy duty equipment for the transportation to, and the placement thereof on site, and the operation thereof on site.
There are several methods of propelling a pipe bursting, and/or cracking and expanding device, and pulling a new pipe through an existing pipe The most commonly used methods are large cable winches, and/or rod pushers or pullers that are usually hydraulically powered, and often used with a pneumatic percussive device helping to drive the pipe breaking device. Winches give continuous motion during pulling, while rod pushers/pullers generally give cycled motion in which they pull, then a rod must be either added or removed, before the return stroke, and next pull stroke. Sometimes rod pushers are converted to cable pullers, eliminating the need for rod removal.
Winches and rod pushers/pullers that can produce pulling forces of up to 75 tons can themselves weigh 2 to 5 tons and must be handled and placed in position to pull; they are powered by correspondingly heavy duty equipment, cranes, trucks, and back-hoes, etc. They also need large excavations, such that the support equipment can take up enough room so as to create traffic problems and even require street closures.
This also means that only large companies with large financial resources can afford the equipment necessary to replace underground pipes, and because the costs and maintenance on this equipment can be high, their prices are also high. Therefore the use of this prior art trench less technology has been limited mainly to the 6 inch or above size pipe of municipal or corporate supply and sewer lines, and is used mainly by large contractors.