SubscribeRotork's innovative self-contained electro-hydraulic actuators have been introduced for the operation of large gate valves during the expansion and upgrade programme at a sewage treatment plant in the Denver metropolitan area of the USA.
The Littleton/Englewood wastewater treatment plant serves more than 300,000 residents, utilising a number of treatment processes to ensure that the water it discharges has no adverse effect on public health or the South Platte River environment – a major water resource for the area.
The Rotork actuators have been retrofitted on previously hand operated 66 inch headworks valves during project work designed to increase treatment capacity from 36 to 50 million gallons per day to meet continued population growth and strict new pollution control regulations.
Mark Van Nostrand, Senior Project Engineer at the Littleton/Englewood plant explains: “We received several automation options, including electric actuators, prior to choosing Rotork’s EH Range electro-hydraulic solution.
The EH was chosen because it operates from a single-phase power supply, provides the speed of operation required to close the valves in the event of a pump failure in the headworks plant and also provides a means for manual override.”The EH Range has also been used by the City of Philadelphia for CSO (Combined Sewage Overflow) applications and other municipalities requiring failsafe valve closing solutions in their wastewater treatment plants.
Intelligent valve control abilities
The Rotork EH Range self-contained electro-hydraulic actuator incorporates an integrated control module, a hydraulic manifold and a power unit comprising a motor, hydraulic pump and reservoir. EH actuators are available in double-acting or spring-return designs for either quarter-turn or linear applications. Torque outputs up to 600,000Nm (5.3million inch lbs) and thrusts up to 5.5million N (1.236 million lbs) are available.
All electronics are protected in a watertight and explosionproof enclosure. Other features include local manual control, indication feedback via dry contacts and 40-20mA signal, or optional digital control via Modbus, Foundation Fieldbus, Profibus, DeviceNet or Rotork Pakscan two-wire communication systems.
The EH Range can be supplied for operation from virtually any single phase, three phase or 24V d.c. power supply.
EH actuators also incorporate technology from Rotork’s IQ range of intelligent electric valve actuators – technology proven in countless applications throughout the world. Standard operational and monitoring features include:
- On/off, ESD (Emergency Shut Down) or valve positioning with better than 0.5% accuracy.
- Diagnostics and fault indication.
- Local valve position indication via illuminated digital display.
- Opto-isolated digital inputs.
- Lockable Local/Remote/Offline selector switch.
- Local Open/Close selector switch.
- Improved safety and reliability through SIL3 and partial stroke capability.
- Non-intrusive infrared cableless commissioning and interrogation using Rotork’s hand held setting tool.
- Separate, double-sealed terminal compartment for permanent electrical component protection.