Actuators cut maintenance costs for sewage plant

Edited by the Engineeringtalk editorial team Jan 31, 2008

Fourteen RGF and twenty GAC filter beds at the water treatment works has been retrofitted with Rotork IQ multiturn actuators and IQT direct drive quarter-turn actuators.

Rotork IQ and IQT intelligent electric valve actuators have been installed as part of a multimillion pound upgrade and modernisation programme awarded to Interserve Project Services at one of the Severn Trent Water Treatment Works.

A total of 136 actuators have been fitted by Rotork's Site Services Division to existing valves on rapid gravity (RGF) and granulated activated carbon (GAC) filter beds to provide a more reliable, economical and low-maintenance alternative to the hydraulically operated system originally installed.

Nikki Holden, Interserve Senior Agent at the water treatment works, explains: "The actuators were specified for the upgrade application in line with the water industry's preference for electric actuation, through Rotork's framework agreement with Severn Trent".

"The choice of installer was the responsibility of Interserve as Project Manager and we selected Rotork Site Services for the work due to their specialist retrofitting skills and extensive experience of similar projects".

Each of the fourteen RGF and twenty GAC filter beds at the water treatment works has been retrofitted with Rotork IQ multiturn actuators on 500 or 600mm inlet and outlet penstocks and IQT direct drive quarter-turn actuators on 200mm air scourer butterfly valves.

Rotork Site Services' scope of supply encompassed an initial valve survey, the design and manufacture of new screwed valve stems and pedestals for the penstocks and adapters for the butterfly valves, actuator sizing, installation and commissioning.

Butterfly valve adapters were sourced from Valvekits, the Rotork Group's dedicated valve accessory company.

Rotork IQ/IQT actuators feature 'nonintrusive' commissioning and data interrogation by means of a bidirectional infra-red link to a hand held setting tool.

A data logger in each actuator stores historical valve operating data including torque profiles which can be downloaded and analysed using Rotork IQ-Insight software to minimise the requirement for routine valve maintenance.

Rotork's contract is part of an GBP8 million investment to upgrade the quality and efficiency of water treatment at the site for the benefit of customers in the Cheltenham and Worcester areas.