Sarah Kellett reports on the challenges faced when operating slurry pipeline valves and how hydraulic actuators prove to be the ideal solution
Operating slurry pipelines in the mining industry can be challenging for operators; actuated valves are required to meet ISO 5208 sealing specifications - zero leakage. The arduous duties demand very high torque actuators to deliver accurate valve control, rapid shut-off and the ability to prevent the potential risk of pipeline fracturing. Precise flow control is also critical. If the abrasive slurry moves too quickly it can destroy the pipeline from the inside, if it moves too slowly it can separate out and cause a blockage. Remote locations of slurry pipelines often require the use of hydraulic actuators with a hydraulic power unit (HPU).
Rotork RHQ high-torque, extreme-duty rack and pinion hydraulic actuators are designed for the most challenging applications, typically found in industries such as mining. The balanced design, comprising four power cylinders and rugged rack and pinion mechanics, creates a very compact footprint and provides efficient power consumption. Cylinder life is optimised through the combination of electroless nickel plating and redundant piston seals, whilst individual cylinders are easily serviced on the valve without disturbing other parts of the actuator. IP68 watertight environmental protection supports reliable long-term operation, with ATEX hazardous area certification also available.
The RHQ actuator is powered using a Rotork HPU. Rotork HPUs meet any global engineering and manufacturing standards. Materials and construction can be customised for hazardous, corrosive or environmentally sensitive areas. The HPUs can include accumulators, redundant pumps or controls, and the multiple prime movers can be solar-powered or gas-powered pumps to back-up traditional electrical drives.
Brazilian mining industry contract
A mining slurry pipeline in Brazil is the destination for a packaged solution of Rotork RHQ valve actuators, control systems and an HPU. The actuators will control 6in and 28in Class 600 metal seated ball valves installed on the tailing adduction slurry pipeline at the Vale Maravilhas III Dam in the greater Belo Horizonte region of Brazil.
The valves and actuation solution has been supplied by Fluxo Integrated Solutions, a Brazilian company specialising in providing automation solutions to markets including oil and gas, steel, mining and chemicals.
Commenting on this project, a Fluxo spokesperson said: “The high torque values required for valves, combined with challenging operation and local technical assistance deadlines, made Rotork the ideal partner for valve automation.”
Sarah Kellett is with Rotork