Failsafe actuators for coal processing

Louise Smyth

Coal extraction application demonstrates the advantages of electro-hydraulic valve actuation

Mount Thorley Warkworth (MTW), an integrated operation of two adjacent open cast mines in the Hunter Valley region of New South Wales, Australia, supplies international and domestic markets with semi-soft coking coal and thermal coal.

Rotork actuators control the flow of water from a two gigalitre (one million tonnes) dam source to the north and south coal processing (washing) plants.

The project includes an actuator on a pipeline supplying water to a new Water Cart Fill Point for routine dust suppression operations.

Each water cart fill requires 120 tonnes of water to be delivered at a pressure high enough to overcome a 10m head.

The Water Cart Fill Point requirement was very demanding, requiring an electric failsafe actuator to operate the isolation valve by solar power (i.e. 24 VDC), to be SIL-rated, and capable of closing a 500mm butterfly valve in 10 seconds.

Rotork was able to satisfy this specification with a standard Skilmatic electro- hydraulic actuator.

Flexibility built in

Skilmatic self-contained electrically powered actuators – comprising integrated control module, hydraulic manifold and a power unit consisting of a motor, hydraulic pump and reservoir - offer flexibility and customisation to suit specific applications.

Utilising an integral spring mechanism to provide the most reliable means of positioning valves to a pre-determined safe position, they have been specifically designed for use in critical fail-safe applications.

They combine the simplicity of electrical operation with the precision of hydraulic control and the reliability of mechanical fail- safe action. With the intelligent control and monitoring systems, the actuators provide an ideal solution for two position, safety shutdown or precise modulating control applications.

The Skilmatic actuator combines absolute reliability with performance monitoring and data logging, including valve torque/thrust signature and profile and status and monitoring diagnostics.

The actuator can be configured using Rotork’s non-intrusive Bluetooth Setting Tool, and datalogger files can be transferred from the field to a standard PC for storage and analysis as part of asset management routines.

Rotork Skilmatic actuators are certified to the following standards: ATEX, INMETRO, IEC, FM, CSA and GOST.

The double-sealed electric enclosure is watertight and dustproof in ratings up to IP68. Specifiable for three-phase, single-phase or DC electrical power supplies, the Skilmatic range delivers rotary torque or linear thrust outputs that are suitable for valves of virtually any size and design.

Sarah Kellett is with Rotork

Recent Issues