Robotic help in sewer lining

Since mid-July 2005, Severn Trent Water, which serves the water and sewerage needs of the Midland region in the UK, has been undertaking a major foul/storm water sewer project in the City of Derby.

Scheduled for completion in March 2006, the sewer rehabilitation and replacement project involves a significant amount of trenchless lining work. Severn Trent is completing the project in association with its approved term contracting partner Whitehouse Construction, based in Ashbourne, Derbyshire.

Whitehouse is doing most of the works, with the lining operations being subcontracted to OnSite, which specialises in flow monitoring, CCTV sewer surveying, managing and maintaining water industry assets. As part of this specialisation, OnSite also designs and installs the Premier-Pipe Lining Process that is being used extensively throughout the Derby project.

In total, 6,164m of lining is scheduled to be completed across Derby, ranging in diameter from 225mm to 1,500mm and at depths of 1.5m to over 6.5m. Lining installations also include brick egg pipelines from 480mm x 370mm to 1,150mm x 780mm, using upwards of 78 lining sites. The Premier Pipe is a long-established thermo-cure resin-based CIPP process that has been used to install upwards of 3,000km of lining across the UK and internationally since 1996.

As part of the ongoing development of the Premier-Pipe installation process, OnSite recently bought a new multi-robotic system through Primo Roboter system manufacturer PMO of Switzerland. The new robots are seen has having a wide-ranging application in the company’s sewer operations.

OnSite’s new robotic system is housed in a specially designed box-van and installed by PMO engineers in Switzerland. The new system comprises a Primo Mini-Cutting Robot and a KA-TE/PMO Grinding Robot along with the control systems and power units for hydraulics and electrics.

The van has a winch facility on board for placing and recovering the robots and the cable and hydraulic hose reel has, at present, a capacity of 85m, allowing operation over a length of up to 170m. There is also the option to increase the cable/hose reel capacity by a further 45m. Within the box-van a comprehensive workshop has been fitted to ensure there is minimum down time while setting the robots to different configurations.

The mini system robot is designed to operate in pipes of DN 150-300. It has a cutter power capacity of 3.2kW. The unit comes supplied with four wheels for DN 200 pipe, four wheels for DN 150 pipe, four axle extensions for DN 250 pipe and four axle extensions for DN 300 pipe. Three cutters including one lateral cutter, one radial cutter 200 and one liner cutter come supplied as standard. The robot unit is fitted with a 270o mini-colour camera, that is panable in 150mm diameter pipes, with adjustable cold lighting. The system utilises two-wire video transmission and has a windscreen wiper.

The larger KA-TE/PMO robot is designed for operation in pipes from DN 225 to DN 900. As well as a 200o panable colour camera with windscreen wiper, the system has an arresting roller for use in pipes up to DN 450 for use when the 5kW capacity cutter motor is operating.

The wheel and axle combinations available cover 225mm up to 900mm diameter pipe set-ups. As well as this the unit is supplied with a narrow invert undercarriage that will enable it to operate effectively in egg-shape and various non-standard configuration pipelines. Sprung stabilising arms are available for attachment to the main body, which prevent excessive roll in egg-shaped pipes. This robot also comes with one lateral cutter, a radial cutter for 250/300 pipes and one liner cutter.

According to PMO, the robots are very advanced in their field and are currently some of the most powerful robotic cutter systems available to the pipeline market. They can be used for pipeline preparation, in terms of removing scale, intruding

lateral connection or root intrusions or other surface defects that may affect the lining installation process.

Once lining has been completed, the robots can also be used to reopen lateral connection along the lined route, quickly and accurately. The robots are designed to utilise optional undercarriage configurations to fit whatever pipe design they need to work in. There is also a wide range of cutter heads to choose from which are designed for various applications and material types.

Fraser Brown, Contracts Engineer for OnSite said: “We have great expectations of this new system. It is a major investment for the company at well in excess of £150,000 and we have a good programme of work already lined up for it.”

The OnSite operating crew was given basic training at the company’s lining impregnation facility near Wantage for two days, with a further three days of site training and PMO supervised operation and instruction in Derby. The first operation for the new robots was to reopen laterals on a 71m-long, 16mm-thick Premier Pipe lining installation in a 640mm x 470mm brick egg sewer in Full Street, Derby, a length with some 17 lateral connections to reconnect. The work was successfully completed in one day.

PMO has four systems operating in the UK, with potentially two more being added to this list in the near future. Robert Smyth, PMO systems consultant said: “We see a significant market for this type of robotic equipment within the UK as increasingly water companies look to rehabilitate their sewer networks. Not only can they be used for significant amounts of site preparation work where lining is to be undertaken, they can also quickly reopen and re-establish networks to full operation once the initial lining are completed.

Tel: 01235 772882.

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