Channel Tunnel Valve Upgrade

Rotork wins a contract to automate valves in the Channel Tunnel.

The contract to automate valves inside the Channel Tunnel presented Rotork Retrofit with an unprecedented list of challenges to overcome, not only relating to the size and physical locations of the valves themselves, but also due to the very restricted timescales available to carry out the work.

The contract involved twenty-four ball valves on a total of 200 kilometres of 400mm chilled water running tunnel cooling pipework running the length of the two main tunnels, which removes the huge quantities of heat generated by the trains that pass through and underground plant rooms. Situated at the mid-point and two cross-over points at each end of the tunnels, the valves are used to configure the flow of water through the appropriate tunnel sections to suit prevailing operating conditions.

Originally, all but four of the valves were manually operated, but the steady increase in the number of trains using the tunnel has dictated the need to automate all of them. This will ensure that the tunnel cooling can be efficiently switched between the appropriate loops for maximum efficiency and economy. For this to happen, the valves need to be remotely operated, using the Eurotunnel central control room and SCADA system, saving the time consuming exercise of despatching operators to the diverse locations whenever valves need to be opened or closed at frequencies of up to once a week. Eurotunnel's chosen solution was to equip the valves with a Rotork IQ electric actuator and Pakscan two-wire control package that would link directly into the Modbus protocol of the tunnel?s existing PLC data highway.

Rotork Retrofit's initial challenge involved the design of suitably compact adaptation to ensure that the actuators would be out of harm's way from passing trains. All the valves are in elevated locations, on the tunnel side, with various valve stem orientations, including inverted. Retrofit designers overcame the constraints of these space restrictions by utilising a combination of Exeeco worm and bevel gear operators with IQ20 intelligent electric actuators.

The task of installation had to be programmed into a very restricted time frame, allowing the work to be performed only at set times at night on Saturdays and Sundays. In addition, access was only possible by means of Eurotunnel maintenance transport, which would deliver and collect the Retrofit engineers at strict, predetermined times. Therefore, as Rotork Lead Engineer John White explains: "it was crucial to ensure that all the equipment to do the job was on board; there was no scope to go back and pick up any forgotten parts. It was equally important to ensure that the job was finished by the time we were to be collected in order to keep the project on schedule."

Specialised hydraulic lifting gear was brought in to hoist the actuator/gear operator packages onto the valves, often using the Eurotunnel maintenance train as a lifting platform. In this way, working in close co-operation with Eurotunnel staff and the cabling contractor, it was possible, on average, to complete one actuator installation during each night of working.

At each of the three locations, a Rotork Pakscan IIS sequencer master station was installed to link the retrofitted actuators to the main data highway, enabling valve monitoring and control to be performed at the central control room. In addition, a Rotork touch screen operator panel has been installed at each site, providing a back-up facility by which the actuators can be operated locally, using Rotork In-Vision software. In-Vision also has a data logging facility that records every actuator command and action, creating an event-by-event database of historical operating information. This information can be used diagnostically to prepare preventative maintenance schedules and avoid unplanned interruptions.

Peter Bithell, Eurotunnel?s M & E Project Manager, has been pleased by the overall performance of all the participants in the retrofit project. He says "Generally the task has gone very smoothly, bearing in mind the enormous amount of organisation, planning and co-operation that was essential for practical and safety reasons."

"Meticulous attention to every detail, ensuring that equipment and staff were in the right place at the right time, enabled the entire project to be successfully completed with no unexpected incidents. With the actuators installed we are now able to begin our programme of pre-planning valve configurations, which will further improve economy and efficiency in the future."