Patchflow-Robotics for In-Pipe Leak Repair

Rory Bateman, Owain Pill
Imperial College London
London, United Kingdom

The frequency of droughts has increased by nearly a third globally since 2000. A U.N. report states that 75 percent of the world could face drought by 2050, and 5.7 billion people could live in areas with water shortages for a month or more every year. Water scarcity due to climate change alone will necessitate a reduction in leakage.

“The idea for Patchflow was created after reading a National Infrastructure Commission report that stated that England could require an additional 4,000 megaliters of water each day by the year 2050,” said Co-Founder Rory Bateman. “Halving leakage in water distribution networks will be essential to making up this shortfall. When researching what plans were in place for this, we found that there were many new technologies that related to improving leak detection but few that aimed to revolutionize the method of fixing the leaks. Considering this is where more of the cost in leak reduction occurs, it made sense to focus there.”

London was chosen as the location for the team’s project as it has one of the earliest piped water distribution systems in the world. With more than half of pipes in London over 100 years old and made of corrosion-prone cast iron makes the city an ideal candidate for the proposed system.

The majority of R&D occurring within the U.K.’s potable water industry revolves around the detection and location of leaks even though this only accounts for 20 percent of the repair process’s cost. Most of this cost in repair is associated with the shutting down of busy travel routes. The product’s USP is its non-disruptive nature, meaning that the water companies can negate the need to pay expensive council charges associated with closing roads.

As the robot travels through the network, it would make use of differential pressure sensors built into its skin, these pressure sensors will detect discrepancies in the water flow. Using these sensors in parallel with physics-based CFD models and neuromorphic processing units, the device would be able to detect exactly where the leak is without the need for visual data.

“Working with drinking water can bring some significant challenges,” said Bateman. “One major challenge was that all materials used in the device must comply with Ofwat regulations. To address this challenge, we implemented an isolation approach to sealing cracks. Another challenge was a lack of information about the contents and makeup of the water network. This means that it is impossible to understand the nature of a pipeline or the crack within until a device is sent down to investigate. This is particularly relevant when repairing cast iron pipes, where tuberculation (the formation of corrosion mounds) is common.”

The anchoring relies upon soft robotics, utilizing silicone-immersed SMAs to enact a retreating infill process. This allows for fast and controllable actuation without damaging the side walling of the pipes. Following alignment, the robot’s secondary anchor begins to expand. Here the SMAs provide heat and pressure for thermally activated resins. This allows for a retreating infill method with cure times between 20-30 minutes. This keeps the repair process short, minimizing the exposure time of the product to drinking water.

Investigation into the cost of setting up and running the system revealed that for the same leak repair budget that Thames Water currently expends, this proposition could increase fixes by approximately 4.2 times. Meaning, it’s possible to catch up and keep pace with new occurring leaks within 8 years of implementation. By comparison, the current Thames Water approach would take around 51 years to reach this same stage. To do this, a fleet of approximately 642 robots will be required. In this theoretical case, the technology could save Thames Water 165 million pounds worth of lost water in the first year alone.

According to Bateman, the project is still under development and the next steps involve addressing the most difficult technical challenges, which will be addressed in several projects over the next year. “Applications will initially be focused on polyethylene pipes as they are technically more feasible to repair. The future vision is to expand this platform to cast iron pipes which pose a greater but more rewarding challenge,” he said.

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