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Rotork supplies control valve actuators to Sydney Water authorities

Rotork's CVA electric control valve actuators are enabling the Sydney Water Corporation in Australia to control the pressure in the city's water supply network with greatly increased response and accuracy.

Water authorities need to control the supply pressure in their potable water pipeline networks throughout the day in response to user demand. Pipeline pressure also needs to be controlled to reduce network water leaks and to mitigate pipe bursts and consequential expensive repairs. To perform this vital function on the Sydney water supply network, Rotork Australia has supplied more than 150 Rotork CVL500 linear control valve actuators with adaptation for fitting to pilot valves.

Typically, spring pressure in a pilot valve is modulated over a short 1-4mm stroke; this controls the output of the pilot valve, which in turn controls the pipeline pressure. Network pressure can range from 15m to over 90m head. The characteristic of the Rotork CVL500 actuator enables very accurate control of the network in increments of 0.4m of head pressure. For the Sydney Water network this is an improvement on the previous coarse control resolution of up to 7m head, just by changing to the Rotork CVL500 actuator. Using a Proportional Integral Derivative control loop, the Rotork CVL500 provides repeatable and reliable ongoing pressure control. A PID controller is a control loop feedback mechanism widely used in industrial control systems.

The Rotork CVL500 actuator can operate in a flooded pit, as the enclosure is IP68 rated, whilst only low power 24V DC or 240V mains is needed. The CVL500 uses Bluetooth to enable remote configuration and monitoring from outside the pit or confined space. With the integral manual override control the CVL500 allows operation with or without power by electrical and mechanical engineers as well as site operators.

The Rotork actuators were supplied to NetWorks Alliance, a collaboration formed by Sydney Water to deliver a programme aimed at reducing leaks and main breaks from the city's 21,000km water supply network. The Alliance provides integrated design-construction of renewals and other water and sewer works across Sydney Water's area of operations.