A ROBOTIC WORKOUT

Abstract

This article describes various robotic techniques for renewing the 230,000km of British sewers, about 10% of the total, that are likely to need renovation or replacement during the next ten years. Local repair is becoming an increasingly popular method of renovation, especially for sewers with only a few local defects rather than continuous defects. Since 1991, robots have begun to be used in the UK for such local repairs. Robotic systems can be used for a wide range of purposes: (1) repair of leaking joints, holes, cracks, and fractures; (2) removal of intruding connections, tree roots, steel reinforcements, scale, and encrustation; (3) handling recessed connections. At present, they are suitable for pipes from 200mm to 800mm diameter, and they can operate up to 70m from an access point. The equipment can be very compact, and can be carried in a van with trailer. The van is used as a monitoring and control centre during repair work. One system uses a robotic pipe crawler, which is set up with a drilling and milling head, lowered into a sewer through a manhole, and then guided along the pipe to the parts needing repair. A specially formulated repair material provides solvent-free, underwater curing, using an epoxy compound with resin and hardener. The resin can be applied in several ways.