Complete control

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.

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.

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.

Using a Proportional Integral Derivative control loop, the Rotork CVL500 actuator provides repeatable and reliable ongoing pressure control and enables 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.