AUMA Actuators Limited’s high-performance, variable speed electric actuators have been installed as part of an upgrade to coarse screen outlets at Thames Water's Beckton Sewage Treatment Works in the east London Borough of Newham - one of the largest sewage treatment works in Europe.
Built in 1864, Beckton Sewage Treatment Works covers over 250 acres, serving a large portion of London north of the River Thames. The upgrade to the plant’s coarse screen outlets included replacing 12 life-expired single speed actuators with AUMA SAV multi-turn, variable speed actuators. AUMA also replaced existing gearboxes, spindle bellow covers, and electrical isolators, emergency stops, local cable tray and supports, with new actuator gearbox assemblies.
Paul Hopkins, Managing Director, AUMA Actuators Limited, explains: “This project required adopting a sympathetic approach to working with existing assets, hence our recommendation to replace the old single speed actuators with new, variable speed options. This allows the plant’s penstocks to be operated sympathetically with a soft start/stop, whilst still being able to operate at a higher speed over the long travel to meet operation time requirements.
"We have also introduced a further innovation which sees all new SAV variable speed actuators fitted with individual auto greasing cartridges mounted to the thrust bases, with cross bores to permit spindle lubrication from this point. Grease cartridges are set on installation for a timed release to extend longevity in-service of the spindles.”
Actuator controls included standard parallel controls, 24v DC commands, with 4-20mA feedback of position. The actuators were supplied with a Profibus disconnect unit within the standard plug assembly and require no hardware or software changes in the future to upgrade to Profibus control.
Matthew Driscoll at Thames Water adds: "Throughout the project we received invaluable support and technical advice from the team at AUMA. In addition, clear communication between AUMA, Thames Water, crane operators and scaffolders meant the installation was completed one day ahead of schedule and caused no disruption to the onsite processes for Thames Water.”
Coarse screen outlets are used in wastewater treatment and other applications to remove large debris, preventing it from clogging downstream equipment or causing damage. They typically consist of parallel bars or rods and are a preliminary form of treatment, acting as a barrier to prevent larger objects from entering the system.
Paul Hopkins concludes: “On project completion, the plant’s 12 penstocks were fully tested and deployed incorporating new E-stops for ease of operation. Our innovative spindle auto greasing system featured a single auto grease cartridge, lubricating both bearings and penstock stem. The end result means Beckton STW is now in a much better situation and site operatives are able to work much more efficiently.”
