In-pipe robotic system for pipe-joint rehabilitation in fresh water pipes

Abstract

Water is an indispensable element for cities as it is for living organisms and humans. Fresh water is transported by pipelines from water sources to cities, reaching _rst the municipal water systems and then the consumers, such as buildings and houses. As water passes through the distribution system, some percentage is lost due to leakages from the transmission and distribution mains before it reaches the consumers. A problem spotted in the cities of Vienna and Bratislava is that the quantity of water sent from the municipal systems mismatch with the quantity of water received by the consumers (houses and buildings). The mismatch in the water readings is considerably high, in the range of 15% to 20%. An initial investigation revealed that the main water loss points are caused by 100km of aged cast-iron pipelines with lead-joint sockets. These aged pipes are more than 100 years old and still in good metallurgical conditions with an expected lifetime of more than 50 years. However, the pipe-joint sockets hemp packs, which ensured the sealing of the pipe-joint, decomposed over the years leading eventually to leakages. Pipe leakage is considered to be a major problem by governments, both from an environmental point of view, wasting a vital natural resource, as well as economical, damaging the supplying systems and foundations of roads and buildings. This research was conducted as part of the European Union project - DevelopingWaterLoss Prevention (DeWaLoP), which is aimed to repair the leaking pipes with lead-joint sockets from the fresh water supply systems in the cities of Vienna and Bratislava. The objective of the project includes: the development of an in-pipe robot that crawls into the one meter diameter pipes and capable to inspect, clean and apply a developed sealant to reseal the pipe-joint sockets. The goal of this PhD thesis is to present the design and development of the in-pipe robot system for this speci_c application. In order to repair fresh water pipelines, the in-pipe robot, as prerequisite must not contain liquids or chemicals harmful to humans. Consequently, the robotic solution integrates only electrical systems to repair the pipe-joints. The developed in-pipe robot consists of two main modules: a control station and an in-pipe robot. Outside the pipe, the control station remotely controls and monitors the movements and status of the in-pipe robot. Inside the pipe, the in-pipe robot is divided in two sub-modules: the _rst is a maintenance unit with a repairing tool system, able to repair the pipe-joint. And the second is a mobile robot, which enables mobility of the in-pipe robotic system. In contrast to commercial robotic platforms which are unable to _x their positions inside the pipe to damp vibrations when repairing the pipe, our developed hybrid locomotion system based on wheeled wall-pressed with integrated suspension system enables the robotic platform to have double functionality: to crawl 100m inside the pipe and to _x the robotic structure to the center of the pipe, enabling its robotic arms to rotate in cylindrical 3D space for inspecion and reparation of the pipe-joint. In this con_guration, the developed mechanical system prevents the fragile cast-iron pipe from damages when repairing it. Thus, the developed in-pipe robot is a multi-functional platform integrating the complete solution for fresh water pipe-joint rehabilitation in non-standard pipe diameters (800 to 1200mm).