Geothermal Pipe Bending
Marshall Oldham, Ryan Turner, Sarah Reiss
Ditch Witch has always been a leader and innovator of underground construction equipment. In recent years, geothermal heat pump installation has become a large industry and many companies use Ditch Witch trenchless equipment for digging wells. Current methods for geothermal installation involve a large hole and multiple small loops sent down hole. The loops are secured with grout in between the pipe and the ground down hole. One of the biggest problems in the process is adding the grout down hole to secure the pipe. Not only is it costly, but also reduces the efficiency of the geothermal system. Ditch Witch has set out to improve the installation process by reducing the amount of grout needed. To reduce the amount of needed grout, Ditch Witch has requested that D.T.E. design a prototype machine to check the feasibility of reducing the outer diameter of 4.5 inch HDPE pipe temporarily. By doing this, a smaller diameter hole can be dug in the ground. This smaller hole will allow the pipe to create a tight fit once down hole and expanded back to its original shape. This will reduce the amount of grout needed to secure the pipe and also increase heat transfer efficiency.
Charles Machine Works, Inc. has assigned the task of evaluating the feasibility of bending 4.5 inch outer diameter High Density Polyethylene (HDPE) pipe into a “U” shape cross sectional area. This will reduce the outer diameter to approximately 3.5 inches when folded. In the original requirements, CMW requested we also design a grout line inserter, banding mechanism, and a spooling machine. As the project progressed, those requirements were dropped due to time constraints. CMW did however, ask that we gather some ideas for banding material and test our ideas. If bending the HDPE pipe into the “U” shape is possible using a prototype machine, then CMW will look into designing and building a machine for production purposes.
Scope of Work
DTE will design and develop a machine to address the problem statement. This machine will crease HDPE pipe into the “U” shaped cross section. The purpose of bending the pipe is to reduce the outer diameter to approximately 3.5 inches. This will allow for a smaller drill hole, tighter fit, and less grout to secure the pipe