Product category:
Process Hardware (Pipes, Nozzles, Heaters, etc)
News Release from: Rotork Controls | Subject: Intelligent electric valve actuators
Edited by the Engineeringtalk Editorial
Team on 06 April 2000
Rotork actuators secure important ship
repair yard
Rotork intelligent electric valve actuators have been installed to update and secure the operation of machinery that controls the dewatering of dry docks.
Rotork intelligent electric valve actuators have been installed to update and secure the operation of machinery that controls the de- watering of three of the country's largest and busiest commercially operated dry docks, at Falmouth in Cornwall The dry docks, owned by A and P Falmouth Ltd, are capable of holding large ocean-going freighters, tankers, ferries and naval vessels
To de-water each dock, huge gate valves are opened to allow the water to drain into a vast underground sump, from where it is pumped back into the sea through discharge valves.
The 78, 54 and 48 inch diameter Glenfield and Kennedy gate valves were originally installed in 1957 and equipped with water hydraulic linear cylinder actuators, operating at 800 psi pressure.
None of the valves were equipped for emergency manual operation.
After many years of operation, the old hydraulic system was at increasing risk of breakdown due to corrosion problems, whilst the spares availability situation for imperial sized seals, hydraulic pump parts and other essential components had become critical.
Furthermore, the lack of hand operation meant that a failure in any part of the hydraulic system would disable all of the valves, effectively preventing any of the dry docks from being emptied and therefore bringing the entire shipyard operation to a halt.
Gareth Parry, A and P Falmouth operator/fitter explained: "Modernisation was crucial.
It would have been impossible to open any of the valves against the imbalance of the 55 foot head of water created by a full dock.
It was essential to change to electrical power which would give us independent operation of each valve, improved reliability, simplified control interfacing and accurate position indication in the control room.
In addition, electric actuators would provide emergency hand operation in the event of a total power failure.
"We wanted somebody who could offer a complete modernisation package.
We were therefore looking for a supplier with the experience and expertise to design and manufacture intricate new valve adaptation, install new actuators with associated power and control cabling, design and install a new operating panel in the centralised control room and commission the entire project.
"One of the reasons for approaching Rotork was that an electric actuator of theirs has been operating our drain pump discharge valve for over forty years and we thought that this was a pretty good recommendation! Also, we wanted if possible to support a British engineering company like ourselves.
In the event, Rotork's Retrofit department exceeded our expectations in their ability to perform every part of this contract, demonstrating nothing but helpfulness, goodwill and thorough good practice." Following the initial site survey, Rotork Retrofit recommended utilising the existing hydraulic cylinders as pedestals for the installation of spur gearboxes, from which extension spindles connect to new Rotork IQ actuators.
These are all pedestal mounted on the mezzanine floor above to provide easy access for commissioning, maintenance and emergency operation.
The installation of the eight IQ actuators was completed by the beginning of the year and, in recognition of the importance of the dry docks to local employment, the new control system was officially opened by Lady Mary Holborow J.P., Lord-Lieutenant of Cornwall, in March.
To mark the event a commemorative plaque has been fitted to the control room wall.
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