The contract to automate valves inside the Channel Tunnel presented Rotork Retrofit with a list of challenges to overcome, relating to the size and physical locations of the valves, but also due to the restricted time available. The contract involved 24 ball valves on a total of 200km of 400mm chilled water running the length of the two main tunnels, which removes the huge quantities of heat generated by the trains 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. For this to happen, the valves need to be remotely operated, using the Eurotunnel central control room and SCADA system. Eurotunnel’s chose 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.
