Rotork CVA delivers accurate pressure control for city’s 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 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 15 metres to over 90 metres head. The characteristic of the Rotork CVL500 actuator enables very accurate control of the network in increments of 0.4 metres of head pressure. For the Sydney Water network this is an improvement on the previous coarse control resolution of up to 7 metres head, just by changing to the Rotork CVL500 actuator. Using a PID* control loop, the Rotork CVL500 provides repeatable and reliable ongoing pressure control.
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 21,000 km water supply network. The Alliance provides integrated design-construction of renewals and other water and sewer works across Sydney Water’s area of operations.