Composite valves save weight and cost

Tom Shelley reports on the advantages of switching from brass to advanced composites in marine valves Making valves for offshore and marine applications out of composites not only ensures corrosion resistance, but achieves weight savings of as much as two thirds relative to their metallic counterparts and is expected to reduce costs to end users by 15 to 20 per cent. Such are the views of Thomas Marotta, chairman and chief executive officer of Marotta Controls based in New Jersey. He says his company started out, "Seven or eight years ago," with a polypropylene plunger. They subsequently moved onto machining glass filled epoxy valve bodies, working with another New Jersey company. They then came across a small British company, Advanced Valve Technologies based in Broadstairs, which is also into special purpose valves and has a technology for moulding glass filled epoxy valve parts. Marotta has been working with AVT on ball valves and butterfly valves. Apart from reduced fabrication costs, parts made from the mouldable glass filled epoxy are able to withstand higher working pressures than the machined material - up to 500 psi (34 bar). The new valves can operate in a wide variety of naval systems, from a ship's fire fighting and damage control to chilled water and vessel fuel supply lines. They can withstand shock, vibration and heavy use as well as their metallic counterparts. And as well as having superior corrosion resistance, the valves are also fire retardant and meet the standards of API 607. Service lives are said to be nearly as long as those of the ships they are installed in. Marotta has also teamed up with another company making composite pipes, with the result that it is now able to offer a range of products from 0.5 in (12.5mm) to 8 in (203mm) nominal sizes. The drastic reduction in weight relative to traditional marine brasses and bronzes should give a significant advantage in the construction of high speed craft, both naval and civilian, and the increase in longevity and consequently reduced life cycle costs should be of interest to all. The new valves are expected to be installed on some US naval vessels during 2006. Marotta Controls also makes "In-Line" poppet valves, whose flow is enhanced by moving valve seats as opposed to moving poppets off seats, also candidates to be made out of composites, as well high pressure solenoid valves, pressure reducers and regulators, pressure reducing manifolds, relief valves, check valves and a a wide range of other fluid control products. Advanced Valve Technologies has also developed valves suitable for use with sulphuric acid from 1% to 99% concentration as well as concentrated hydrochloric acid. The company has approvals from Lloyds Register, ABS (American Bureau of Shipping), UKAS, Zurich and TUV. Marotta Controls Advanced Valve Technologies Pointers * Composite valves enhance corrosion resistance * They are one third to one half the weight of valves made using traditional materials * Life costs are likely to be 15% to 20% less than those associated with valves made from traditional materials