A 750MW prototype machine has been subjected to intensive testing off Orkney for a number of years, and three production specification machines will soon be commissioned off northern Portugal as part of the world’s first commercial wave farm. When complete, this project will embrace over 30 machines and generate 22.5MW, to meet the demand of some 15,000 Portuguese households.

The Scottish Executive also recently announced a £4 million funding package to support a £10 million Scottish Power Pelamis wave generation project in Orkney, and a 5MW project is planned for the seabed 10 miles off Hayle in Cornwall by E.ON UK and Ocean Prospect, involving seven Pelamis machines.

The hydraulic systems which form the heart of the Pelamis machine required specialist expertise, and Ocean Power Delivery have worked in close cooperation with Sun Hydraulics on the design, configuration and manufacture of the systems employed. Sun Hydraulics is one of the world’s leading designers and manufacturers of high performance screw-in hydraulic valves and manifolds and specialises in the development of customised products.

Barry Lovell of Sun Hydraulics, said, ‘Because of the highly corrosive salt water environment the Pelamis hydraulics have to operate in over many years, we were presented with the challenge of producing custom valve and manifold components with exceptional corrosion resistance and good handling characteristics.

‘The large SG iron manifolds, in particular, have several cartridge cavities, ports and tapped holes, are difficult to handle and are potentially vulnerable to corrosion. We therefore have to protect both the external and internal surfaces with a coating that ensures maximum corrosion resistance. In addition, the coating has to be thin to meet the required tolerances, allow bores to be protected from rust during storage and facilitate final assembly without damaging the surface.’

Sun Hydraulics approached the Armourcote division of Surface Technology plc at an early development stage for a suitable solution. This initial approach coincided with the development by Armourcote of a new electrodeposited multi-layer, thin-film coating, ‘TriCem 3800’, with superior anti-corrosion properties, which met all the necessary criteria and, following rigorous salt spray and wear tests, was subsequently adopted by Sun Hydraulics for coating the critical Pelamis manifold.