Scandinavian success for Hewitt Robins
Company supplies triple-deck washing screen to one of Norway’s leading quarry operators
HEWITT Robins have recently supplied a 3.0m wide x 9.6m long triple-deck washing screen to Norstone’s biggest plant in Norway. Norstone, part of HeidelbergCement Northern Europe, have completed a phase 2 upgrade project for a new screen/rinse system at Tau Quarry. The site currently produces 2.3 million tonnes of aggregates a year and, with the recent upgrades, the operator aims to increase rail ballast production by an additional 500,000 tonnes.
The Hewitt Robins 2QV-14 washing screen has been specifically installed and commissioned to help achieve this. The heavy-duty screen was installed by Agdermaskin, Hewitt Robins’ partner in Norway, who also designed and installed the stand-alone washing plant, which is situated near a ship-loading facility in order to rinse the railroad aggregates or other products before shipping.
The screen currently handles 1,500 tonnes/h of railway ballast, as well as over 10,000 litres of water per minute in the feed and from the sprays. The screen is required to wash the material prior to being loaded on to a ship and also takes out –20mm waste. The top deck separates at 45mm, the middle deck at 20mm and the bottom deck at 4mm, all using Tema Isenmann WS85 heavy-duty modules.
The screen is constructed with 15mm thick side-plates, which include additional 15mm thick doubler plates around the vibrator units. The heavy-duty cross members are spaced every 600mm to be able to withstand the large amounts of aggregates and water and the total weight of the machine is more than 30,000kgs.
The 2QV-14 vibrating unit is oil lubricated and consists of four pods incorporating two 140mm bearings in each pod (eight bearings in total), giving the screen increased bearing life. The four Quad-V Pods are timed together using a timing belt on the no-drive side and the pods are coupled together through the centre of the screen using two cardan shafts.
The cardan shafts take up less space than conventional shafts and vibrator tubes, thereby providing additional access between the decks for easier maintenance when changing modules.
‘The new stand-alone washing plant incorporating the heavy-duty Hewitt Robins 3.0m wide x 9.6m long three-deck washing screen has allowed us to increase our production at Tau and supply a higher quality product,’ commented Bjorn Ingvalstad, technical manager at Norstone.
‘The project was completed on time and within budget. Operationally the screen is handling the required capacities and gives us an exceptionally clean product.’