Cross has designs on large sea water filters

With its new design, Cross claims to have developed long lasting, money saving, reliable automatic filtration equipment that can be installed in modules to meet the needs of large scale installations such as desalination plants, coastal power stations and cooling tower circuits which, it says, could all see huge savings in relatively short timescales. Smaller applications such as sea life centres and marine developments could also use the same product on a smaller scale. The technology is based on a patented stainless steel "zero gravity" filter coil which is already in widespread use in many areas of industry including water and wastewater treatment and heating and air conditioning plant rooms. A set of filter coils is fitted into a pod and each pod can be backwashed individually and automatically at a selectable differential pressure value. The filtration process is not interrupted which ensures minimal effect on flow and the requirement for any redundant filtration capacity is eliminated. Automation is PLC controlled and actuation is, in larger systems, pneumatic. The key to this latest project has been to identify materials that not just withstand the incredibly corrosive nature of sea water, but also the destructive action of erosion caused by silt heavy estuary water. Cross's research concluded that a filter coil made from alloy 625 combined with a large polypropylene housing, polyethylene pipework and bronze backwashing valves is the way forward for large scale sea water and estuary filtration systems. An all metal construction is also being designed for high pressure systems or where there may be higher temperatures. While long term trials continue, Cross is keen to bring its experiences and research to those who need it the most and is encouraging industries, environmental agencies and coastal businesses to contact the company with a view to installing pilot plants in any genuine seawater or estuarial application.