In-Pipe Maintenance Robot Using Spray-In-Place Pipe Technique for Long-Distance and Complex Pipe Environment

Conventional pipe rehabilitation technologies are not the most sustainable solution for the utility industry because of various drawbacks, such as time consumption, disturbance to operations, society, and traffic, and the production of waste material. However, aged underground metal pipes are affected by natural forces. Trenchless rehabilitation technologies have been introduced for the treatment and renovation of aged pipes to ensure that utilities are safe and durable from an economic perspective. This paper proposes a portable and automatic robotic solution for a trenchless spray-in-place pipe approach for small underground pipelines. This approach shortens the duration of the rehabilitation operation from approximately a week to < 5 h. The robot delivered and monitored a protective well-mixed urethane coating with plural components accurately using rotary mixing and spraying with a low-pressure and safer configuration (< 0.8 MPa). The robot exhibited superior capacities in complicated pipe environments for turning into 90° elbows and 6-in. (150 mm), 8-in. (200 mm), and 10-in. (250 mm) pipelines. An automated robot was deployed and rehabilitated at various underground and on-ground pipe sites. The spray performance was validated using tensile tests. This robot can be applied to any pipeline system and can be developed for other in-pipe robotic construction and renovation approaches.