Rotork modulating electric valve actuators have been installed in an efficiency upgrade project at a large water treatment works serving the Dutch capital city of Amsterdam. The modern and highly automated plant at Vogelenzang, owned by Waternet, has a daily water treatment capacity of 180,000cum. The treatment regime comprises pre-screening, carbon filtration, ozone injection and sand filtration. Reliability problems had arisen with the electric actuators on the carbon filtration plant at Vogelenzang, which were failing to cope with the modulating valve duties required for efficient filtering and backwashing operations.

Rotork’s solution has been to remove the old actuators, install IQTMPro quarter-turn modulating actuators directly onto the affected butterfly valves and connect to the existing power and control cabling. This work has been performed by Rotork Site Services, Rotork’s specialist division for retrofitting, site maintenance and repair activities. The site wiring interface with the old actuators was by means of plug-and-socket connections. In order to retain these, Rotork engineered a separate plug-and-socket housing, locally sited by each new actuator and connected to the actuator terminal compartment.

This has speeded up installation and enabled the new actuators to be retrofitted with minimal modification to site wiring. On completion of the project, a total of 120 Rotork IQTM1000 actuators have been installed on DN350 and DN400 butterfly valves. Rotork has also been awarded a ten-year maintenance contract for the actuators, involving tri-annual inspections and functional testing.