20110005291 | METHOD AND APPARATUS FOR FORMING UNDULATING CONDUIT - Method and apparatus for forming conduit or pipe of various sizes into undulating, helical pipe by feeding a length of conduit at a controlled rate through a bending mechanism while also continuously rotating the pipe at a controlled rate so that bending occurs in multiple axis directions and the diameter of the helical path of the conduit centerline of the coil is less than the conduit diameter, the pitch is greater than the pipe diameter, and a straight open channel is retained through the pipe coil. | 01-13-2011 |