The explosion at the Buncefield oil storage depot in Hertfordshire closed the nearby distribution centre of Waverley TBS, in December 2005 – the worst possible time for a company that sell wines and spirits to restaurants, clubs and public houses. The blast, possibly the largest in peacetime Europe, destroyed a large part of the building and left the conveyor system covered in rubble and exposed to the winter weather.
Temporary premises were secured three-quarters of a mile away, where European Conveyor Systems (ECS) installed the repaired equipment from the damaged building a few months later. Meanwhile Waverley and ECS were starting to design a new conveyor system to be installed in the re-built warehouse.
The original ECS conveyor system, installed when the warehouse was built in 2000, had been designed to separate full case picking from single bottle picking to speed up warehouse operations. While full cases were picked from pallets by low-level trucks, a special picking system nick-named Fast Alley was created solely for single bottles, involving a separate semi-intelligent conveyor system serving an area with live storage modules.
All orders were planned, picked and dispatched using paperless systems. In Fast Alley, hand-held computer terminals scanned a unique barcode on each tray, telling the operative which product location to visit and how many bottles to pick. Fully picked orders then moved automatically to a packing bench for checking, sealing and labelling prior to dispatch.
While this was a considerable improvement on the previous picking system, operatives still had to walk long distances, and some operations were still manual. The conveyor system in the rebuilt warehouse, which now houses about 2,500 product lines, has been further automated and now provides a throughput of 15 trays (30 cartons) a minute.
The new conveyor system handles pairs of pre-erected cardboard cartons that are placed into wooden trays with a unique barcode licence plate. Empty trays are accumulated under zero pressure on an induct conveyor with a fixed barcode scanner at the exit end. This scanner reads the barcode of the tray, and the interface to the warehouse management system allocates this tray to the next customer order. The tray is then released and routed automatically to the picking area.
The warehouse has two pick tunnels, each with eight picking spurs. The trays are routed to the correct picking spur after being scanned by a fixed barcode reader and via lifting belt transfers. Should a picking spur be full, the tray by-passes it and visits the next destination on its order list. The tray re-visits the pick zone it has missed automatically before leaving the picking area. As before, all orders are planned, picked and dispatched using paperless systems. Hand-held computer terminals scan the unique barcode on each tray, which tells the operative which product location to visit and how many bottles to pick.
The picker also scans the storage location to confirm that this is the correct product before picking the requisite number of items. Once fully picked in that zone the operator pushes the tray on to a take-away conveyor for routeing to the next picking zone or to dispatch if the order is complete. There is a facility on the hand held terminals to enter exceptions — for example, items out of stock.
Fully picked orders move automatically to a pre-determined dispatch spur for consolidating with full cases picked from the pallet racking area.
At order start two cartons are always placed on a tray. If the second carton is not used, it is returned to the induct area. Waste packaging materials are taken on a separate conveyor above the picking conveyors to a waste compacter.
Before arriving at the dispatch spur, the cartons are check-weighed and automatically labelled with the order details and delivery address. The system detects whether one or two cartons are present, and they then pass to a decanting machine where they are separated from the trays. The cartons are then sent to an automatic case sealer and strapping machine, while the trays are routed back to the induction conveyor to be allocated a new order.
After being sealed and strapped, the cartons pass on to a sortation conveyor and are diverted into a pre-determined dispatch spur via a pivoting wheel transfer. Items that are too high to pass through the strapping machine are sent on a by-pass lane to a reject/checking spur where they are manually sealed. The by-pass route is also used for any order that has shortages or is over or under weight.