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 180,000m3.
The treatment regime comprises pre-screening, carbon filtration, ozone injection and sand filtration. Waternet is the only water company in the Netherlands to cover the entire water cycle, from the treatment of waste water and provision of drinking water to cleaning and maintaining levels of surface water. These services are performed on behalf of the Regional Public Water Authority – Amstel, Gooi and Vecht – and the city of Amsterdam.
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.
All Rotork IQ actuators incorporate standard features designed for increased functionality, optimum plant utilisation and improved long term asset management. For example, an integral data logger stores historical operating data, including the sequence of valve torque profiles. This information can be downloaded and analysed with Rotork’s PC-based IQ-Insight software to establish predictive maintenance schedules or identify potential problems.