Amount awarded: £230,930
Led by: Thames Water
Partners: Wessex Water, Dŵr Cymru Welsh Water, The University of Sheffield, Synthotech Ltd
Project completed: October 2023
Further details on Pipebots for Rising Mains (Phase 1) are available on the Thames Water website.
This project tested the feasibility of developing an ‘in-pipe’ live rising main condition inspection tool by harnessing the expertise of academia and industry beyond the water sector. The scope of the project was to design, build and test a novel sensor inspection system, mounted on a robotic platform. The project commenced in April 2022 and was completed in October 2023. The project primarily aligned to the second of Ofwat’s strategic innovation themes, namely to: ‘Protect and enhance the environment and natural systems, to protect current and future customers from the impacts of extreme weather and pollution.’
In some areas of the sewerage network, flow needs to be pumped from a low level to a higher level for subsequent discharge or treatment. Rising mains are the pressurised pipelines that convey raw sewage from pumping stations over these lengths. A rising main failure can lead to severe environmental impact, as pressurised sewage flow from a large-scale burst or leak is likely to result in pollution via uncontrolled sewage discharge. The pipeline materials are predominantly cast or ductile iron and typically range from around 100mm to 1000mm diameter. Managing sewer flows in the event of a burst can be complex and have a widespread impact on customers. If a pumping station and rising main need to be isolated to undertake a repair, upstream flows are transported via road tankers which can be a disruptive operation.
There are currently no ‘in-pipe’ live rising main condition inspection tools available to asset managers. Such tools are desperately needed to enable operators to assess the condition of mains, identify defects, then plan and undertake rehabilitation works. This capability would reduce the risk of failure leading to pollution by enabling proactive targeted repair.
The project successfully delivered a research and feasibility study as set out in the objectives. This led to an application for further funding and development in WBC4. The application was successful and the Phase 2 project was announced by Ofwat in May 2024.
Pipebots is an abbreviation of the words ‘pipe and robots’. The term covers a range of robot systems being developed for pipe networks by a partnership of universities, supported by UK Research & Innovation (UKRI) and the Engineering and Physical Science Research Council (EPSRC). The Pipebots for Rising Mains project aimed to build on expertise developed by The University of Sheffield during their Pipebots work, to investigate the use of acoustics as an inspection tool for pipelines.
Collaborative working was key during the project. Synthotech has experience developing and operating inspection and repair systems for gas pipelines using robotic tools. The project enabled the academic and commercial teams to work closely together to test and develop the feasibility of a rising main inspection system.
The project started with site visits to pumping stations and rising main assets within the partner water company areas. At these live sites, the University of Sheffield were able to undertake initial trials of their accelerometer system to test feasibility for condition assessment. Synthotech were able to get an overview of the general layout of rising main assets and the challenges ahead for access. Statistical data on rising main assets including diameter, lengths, age, materials and burst history was provided by the partner water companies. A target of 300mm diameter metallic pipe was chosen as the initial project focus. Metallic pipe in all forms constitutes the largest proportion of the asset base and operational failures due to material deterioration.
The University of Sheffield tests showed that single axis accelerometers mounted on the external surface of a pipe could measure fractional movements during pump cycles. On this basis, the variance of movement could be used to assess condition. The next step was to apply the concept to triaxial accelerometers within a pipe. The aim was to measure the dynamic movement of the fluid as a result of the pipe wall deformation due to pressure waves. In parallel with this work, Synthotech reviewed existing condition assessment sensors and considered suitable housings and transport systems to operate within a pipe.
The form of the novel inspection system evolved and a tethered tracked robot with a halo of accelerometers emerged. In concept, the robot would enter the live rising main via a pressurised launch housing on a tee. Once in the pipe, the robot would track along the invert with the accelerometers on the halo positioned near the pipe wall. A sound wave would be introduced via a waterproof speaker to generate the pressure wave. Measurements from the accelerometers were recorded, the robot moved forward, and the process repeated. Extensive rig testing and computer modelling was subsequently undertaken to evaluate the potential performance of the system.
The scope of this project was ambitious and the timeline challenging. During the project, the team undertook field tests, designed and built a robotic transport system, developed, tested and interpreted data from novel sensors and undertook rig tests. Significant outputs in terms of hardware built, testing and reporting led to a completed proof of feasibility.
The use of fluid-borne triaxial accelerometers as a pipeline condition assessment tool was investigated and the results from the tests were encouraging. The trials showed that variance in pipe wall thickness could be determined and defects successfully identified with sensors mounted on a robot. Further work is needed on the interpretation and calibration of data, the mounting of the accelerometers and the form of the transport system.
This work is now being addressed in the Pipebots for Rising Mains Phase 2 project. Further development is underway to produce a prototype device for live site trials. This Water Breakthrough Challenge 4 project is due for completion in June 2026.
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For more information on Pipebots for rising mains, take a look at the following resources:
