Rotork provides accurate pressure control for Sydney Water network

Rotork Australia’s CVA electric control valve actuators are enabling Sydney Water to control the pressure in the city’s water supply network with greatly increased response and accuracy. The actuators were supplied to NetWorks Alliance, a collaboration formed by Sydney Water to deliver a program aimed at reducing leaks and main breaks from the city’s 21,000 km water supply network.

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 supplied more than 150 CVL500 linear control valve actuators with adaptation for fitting to pilot valves.

One of the Rotork CVL500 control valve actuator installations at Sydney. The actuator’s IP68 watertight enclosure facilitates installations in pits without fear of problems caused by flooding.

Typically, spring pressure in a pilot valve is modulated over a short 1-4 mm stroke; this controls the output of the pilot valve, which in turn controls the pipeline pressure. Network pressure can range from 15 to over 90 m head. The Rotork CVL500 actuator enables accurate control of the network in increments of 0.4 m of head pressure. For the Sydney Water network, this is an improvement on the previous coarse control resolution of up to 7 m head.

Using a PID control loop, the actuator provides repeatable and reliable ongoing pressure control. It can operate in a flooded pit, as the enclosure is IP68 rated, while only low power 24 VDC or 240 V mains is needed. The product uses Bluetooth to enable remote configuration and monitoring from outside the pit or confined space. With the manual override control, the actuator allows operation with or without power by electrical and mechanical engineers as well as site operators.