Control relays aid in green living project

Edited by the Engineeringtalk editorial team Jan 6, 2003

Bury Pumps turned to Moeller's automation and switchgear solutions for its state-of-the-art water filtration and recycling system for the pioneering Ecotech Centre at Swaffham, Norfolk.

Water is a valuable resource.

Increasingly, industry is bearing the true environmental cost in its supply and treatment, and is looking to technological solutions to reduce this burden.

With this in mind, Bury Pumps, based in Bury St Edmunds, has turned to Moeller's automation and switchgear solutions for its state-of-the-art water filtration and recycling system, built by the company for the pioneering Ecotech Centre, Swaffham, Norfolk.

The Ecotech Centre promotes sustainable development to the community.

The site includes an impressive 67m 1.5MW wind turbine and demonstrations of sustainable agricultural systems.

The building is one of the largest volume timber structures in the region and features the best in environmentally friendly design and construction.

Its wooden structure uses UK-sourced timber from sustainable forests, passive solar heating, biomass fuelled heating and natural ventilation.

Additionally, the building's sophisticated computer control system optimises its energy requirements and climate.

To complete the building's sustainable credentials, the Ecotech Centre supported by the Waste Recycling Environmental Network and Anglian Water, is installing a system to recycle the rainwater collected from its 1000m2 roof.

Bury Pumps was selected to design and install the system.

The system's main components comprise a rainwater storage tank, biological tank with aerator, sand filtration column, activated carbon filtration column and final water holding tank.

The sequence of recycling and filtration starts with rainwater collecting in the storage tank, which is then pumped to the biological tank where bacteria remove organic contamination.

Water is then pumped to the sand filter column to remove particulates and to the activated carbon column where any remaining organic material and other pollutants are removed.

After this stage chlorine is added for disinfection.

Water then passes to the final water holding tank before being pumped by the roof transfer pump to the Ecocentre building's loft holding tank.

At regular intervals the roof transfer pump back flushes the filter columns for cleaning.

At the heart of this system controlling pumps and solenoid valves is a Moeller Easy 619 AC RC intelligent relay.

The Easy's sensor inputs are used for float and level switches, while its outputs are used to control pumps and solenoid valves.

The relay's real time clock activates back flushing, while timer relays set the period of operation of pumps and valves.

Motor protection for the pumps is provided by four of Moeller's PKZM0 motor protective circuit breakers, while switches for the system's control panel comprise the company's attractive RMQ Titan range of push button and rotary switches.

Of course, power for the system is sourced from the wind turbine.

David Vickery, Bury Pump's engineering manager commented: "The Easy 619 relay provides an ideal solution for our requirements, with a generous number of inputs and outputs and a sophisticated set of timers.

It's simple to mount and wire, significantly reducing both installation and commissioning time".

With the control panel situated in the filter shed, Moeller's RMQ Titan control circuit devices were selected for their IP66 protection rating and extended operating temperature range.

Employing LED technology rather than filament bulbs for illumination, the RMQ Titan range of pushbuttons are brighter, longer lasting and more attractive than other ranges.

Vickery added: "The Ecocentre plan to extend the system by recycling sewage cleaned through a reed filter bed and then passed through the rain water recycling system.

The Easy relay unit is very flexible, allowing the additional pump and sensors required to be simply added to the system".