Leeds based corrosion protection and engineering services specialist- Corroserve was contracted to repair and corrosion protect a 36” inlet flow valve which had been in service at Ladybower Reservoir for over 60 years.
Ladybower Reservoir, situated in the Upper Derwent Valley in Derbyshire, holds some 28 million cubic metres of water when full and is the largest of three connecting reservoirs which supply the water needs of Sheffield and the East Midlands.
The reservoir’s inlet flow control valves have to withstand the most demanding requirements of water system control – including erosion and corrosion, so a reliable protective coating system that would ensure the valve would require minimal maintenance over a long period of time was required.
Corroserve’s proposal was to abrasive blast clean the valve body and internal parts then apply a high performance coating system comprising: Polyglass VEF, Plasmet ZF and Corrothane AP1.
The proposal was accepted and following delivery at its Leeds factory, Corroserve first abrasive blast cleaned all the internal and external surfaces in accordance with ISO8501- 1 Sa2½, to remove corrosion and provide a surface profile suitable for subsequent coating.
Multiple coats of Polyglass VEF were then applied to all internal surfaces to achieve a minimum of 1000 microns dry film thickness. To complete the contract two coats of Plasmet ZF and a topcoat of Corrothane AP1 were applied to the valve externals. After curing, thickness and spark testing was carried out to ensure the quality of the coating work.
Polyglass VEF is excellent in immersed environments and is resistant to chemicals across the pH range. WRAS approved VEF is suitable for town water and potable water service.
The contract was completed on schedule and the professional preparation and coating application will ensure that corrosion attack will be minimised and the valve will enjoy a significantly extended service period. The customer can also expect a fast return on investment due to reduced maintenance intervals when the valve is out of service.
