Thames Water is the UK’s largest water company, providing essential services for 15 million customers in London and the Thames Valley. The company invests heavily in new technologies and improvements to increase efficiency and meet the challenges imposed by strict environmental regulations. A framework agreement for the supply of Rotork valve actuators contributes to the achievement of these objectives through the upgrading and automation of flow control equipment in many areas of Thames Water’s operations.
Rotork also assists Thames Water with the design and installation of valve and actuation plant upgrades. As illustrated by two recent examples, these contracts often include extended scope engineering disciplines that can be provided by Rotork Site Services, resulting in a simplified contractual route and a reduced requirement for additional sub-contractors. Both examples involve the installation of Rotork’s latest IQ3 non-intrusive intelligent valve actuators, incorporating sophisticated diagnostic technologies for increased efficiency, reduced maintenance and improved long term asset management.
The first site is a river take-off inlet to a raw water pumping station, where IQ3M modulating actuators have been installed to replace locally operated electric motors on three large river gates. The upgrade enables the gates to accurately maintain a steady flow into the pumping station under all ambient conditions by automatically responding to changes to the condition of the river. The old motors were controlled from a switch panel inside an adjacent kiosk, but the unpredictable requirement for operation at any time, day and night, could cause operating delays which, combined with the restricted ability to accurately position the gates, resulted in potentially problematic fluctuations in the water supply to the pumping station.
The IQ3M actuators now operate automatically from a 4-20mA control signal from ultrasonic level sensors and a PLC, enabling accurate, responsive and virtually unlimited gate movement in small increments, 24 hours a day, without any human intervention. The installation is monitored in the site’s central control room, from where the actuators can also be remotely operated if necessary.
In addition to the supply and installation of three Rotork IQ3M actuators and multi-turn gearboxes, the work undertaken by Rotork Site Services also involved the design and manufacture of new adaptation between the river gates and gearboxes, the removal of the old motors and cabling, the installation of electrical isolators and new power and control cabling between actuators and the kiosk, modifications to the distribution board in the kiosk and the provision of an uninterrupted power supply. Mechanical and electrical installation and commissioning of the actuators was completed within the time allowed, without interruption to the normal operation of the treatment works.
At the second site, at another major water treatment works, Rotork has automated large manually operated penstocks on the inlet to a reservoir. Rotork Site Services performed a complete mechanical and electrical upgrade on one 60 inch and four 54 inch penstocks, involving the removal of old gearboxes and pedestals, the design and installation of new pedestals and installation of IQ3 actuators and bevel gearboxes. The electrical work encompassed new isolators and floodlights, cabling between the actuators and an existing kiosk and modifications to an existing distribution board.
In both cases, the replacement of old equipment with Rotork actuators has improved the efficiency of what had been laborious and time consuming processes. David West, Thames Water’s West London Abstraction Engineer, comments:
“At the first site the new inlet gate actuators and associated automated control system will allow us to run the inlet channel at a higher level than was previously possible. This will save us significant pumping energy costs by increasing the suction head on all our raw water pumps.
At the second site, installation of actuators and site lighting makes isolation of this statutory reservoir quicker and safer. What was recently a very physical four man job for several hours is now carried out by Rotork actuators.”