|Visual Robotic Welding
The VRW process allows for free-hand welding in areas inaccessible to a human and where automated welding is not possible because of unknown or changing weld conditions. Visual Robotic Welding has been designed for remote internal pipe repair but this technique could be adapted to other situations. One example would be welding in high radiation areas. VRW presently travels through a pipe by means of motorized winches located at each end of the pipe under repair. The current prototype is sized to repair pipes from 12 to 24 in. diameter but the basic design can be adapted to larger or smaller spaces.
The VRW process combines closed loop control of a specially developed robotic welding arm and an adjacent robotic camera arm. Both arms articulate and have the ability to move about five independent axes. They are each remotely controlled by an operator who may be located at distances up to 25,000 ft. The current prototype has successfully operated at distances of 1000 feet.
An additional a surface preparation robotic arm has been developed for surface treatment of the pipe surface before and after repair. This arm is equipped to grind and wire brush the surface and is articulated about the same five axes of motion as the welding arm. There is an additional camera arm that monitors the surface preparation process.
The Visual Robotic Welding process could have an impact on the pipeline repair industry. Present pipeline repair technology requires that a leaking section of pipe be excavated and repaired from the outside. Many times this results in excavation and subsequent repair activities in hazardous or otherwise undesirable locations such as under highways, waterways or large structures. With the Visual Robotic Welding process, the pipe can be weld repaired internally from a convenient remote location without the need for costly and/or inconvenient excavations, at a fraction of the time and cost of traditional methods and with minimum impact on the availability of the system under repair
The Visual Robotic Welding process was developed to repair leaks in the proton beam transport pipes for the Fermilab fixed target research program. These proton beam transport pipes are up to 1800 ft. long and operate under high vacuum. They are buried as deep as 30 ft under the ground and, in many areas, may be under several feet of steel radiation shielding. These proton beam transport pipes have been in place for over 20 years and have recently developed leaks caused by corrosion. Excavation costs associated with repair of each leak is approximately $150,000.00. In addition, during excavation workers could have been exposed to low levels of radioactivity induced over the years in the soil, shielding steel and pipe. Now, using the Visual Robotic Welding process, welded repairs in these pipes can be made in a fraction of the time required for conventional excavation and repair techniques, at a cost savings of over $100,000.00 per repair.
Other Visual Robotic Welding process applications now feasible include repair of water pipes, vertical oil or water wells, gas pipelines, or utility cable vaults. Other potential, but undemonstrated, applications of the Visual Robotic Welding process could include any situation requiring welded repairs in spite of physical or space limitations or in the presence of conditions hazardous to humans. The Visual Robotic Welding process can be adapted to larger or smaller scale applications. For example, assembly of a welded metal structure where radiation levels make approach by humans impossible or performing a welded repair inside a pipe only a few inches in diameter. A proposal for adapting the Visual Robotic Welding system for deep well piping is presented here: VRWII
The costs in both time and money associated with excavating leaking pipes is prohibitive in many instances and, in the case of deep vertical wells and pipes under waterways, impossible. The Visual Robotic Welding process now provides for entering a leaking pipe at a convenient or safe location and performing a welded repair. With the costs and difficulty of repairing and maintaining pipelines, wells and similar underground structures world wide, the Visual Robotic Welding process will provide solutions to repairs that until now could not have been considered..