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New Unloading and Storage System for Day Aggregates
New Unloading and Storage System for Day Aggregates
17th October 2006

Further south, Duo Manufacturing has just completed a new unloading and storage system at the Purley, south London rail depot of Day Aggregates. Awarded the main mechanical and electrical engineering contract, the project involved the replacement of the existing rail unloading facilities with a completely new bottom discharge wagon unloading system and associated tripper conveyor and toast-rack storage facilities in a move to improve both operational and environmental efficiencies at the site.

The new facilities allow material to be discharged from rail wagons into two hoppers which feed directly on to a pair of parallel inclined discharge conveyors, feeding aggregates on to the plant's main tripper conveyor. The plant also includes a wheel loader-fed reclaim/blending system, which is adjacent to the main primary discharge conveyors and also feeds on to the tripper conveyor.
This system is designed to ‘communicate' permitting the addition of up to 60% recycled material for the production of primary/recycled blends.

Rated at 1,600 tonnes/h, the tripper conveyor extends 166.5m in length and provides 110m of actual discharge capacity. The tripper carriage which houses a reversible transverse conveyor discharges products into the appropriate stock bays which support the tripper structure and offer a total storage capacity of around 22,000 tonnes. The entire discharge and stocking system is controlled by a PLC via a touch screen, which is mounted alongside CCTV monitors in a small GRP control room situated adjacent to the rail discharge section. The PLC also controls the new installed dust-suppression and water-addition systems.

These new facilities at Purley now offer considerable functional and environmental benefits not only for Day Aggregates, but also their nearest neighbours. As the entire unloading process is now a one-man operation all incoming materials are automatically dispatched directly to designated storage bays via the tripper conveyor. Additionally, with revised locomotive movements and train length the effects of noise pollution have been mitigated, whilst the total elimination of grab unloading operations has eradicated nuisance noise.
Moreover, the new bottom discharge unit, tripper conveyor and toast rack storage facilities have facilitated the installation of permanent and effective and dust-suppression and control measures at the site.

As the blending of primary and recycled aggregates become increasingly common, the new facility offers Day Aggregates a major commercial advantage by providing the company with the ability to create blends containing up to 60% recycled material from their on-site construction and demolition waste recycling facility.

Commenting on the newly completed installation, Day Aggregates' operations director Nick Sadler singled out DUO Manufacturing for particular praise, describing their contribution to the project as exceptional. ‘They knew we were nervous about the project to begin with, but their performance, flexibility, ability to meet deadlines and attention to detail was outstanding and very reassuring,' he said. ‘We spent a lot of time drawing up detailed plant specifications for Purley with the help of Michael Swanson, a quarry plant and bulk material handling specialist, but DUO had no problem meeting these specs and in places improved on the designs using their experience, common sense and logic. The project was seamless from start to finish.'