In January this year Terex Material Handling’s Demag Service Team completed a major refurbishment of the Gypsum & Filler Store Demag overhead travelling crane control system at our Rugby Cement Plant.
Some 30 lorries per day deliver raw materials, tipping it into reception pits. The crane moves material from the reception pits to the appropriate storage bays, before further transfer to the hoppers, which feed the plant’s 3 Cement Mills via conveyors.
The CEMEX Operations & Technology Project Team recognised that heat and dust in the arduous working environment had been causing system faults. In addition, some of the crane system’s components, including the Siemens S5 PLC, were no longer supported by manufacturers. CEMEX and Demag engineers worked together closely to engineer a solution to provide improved performance and increased capacity.
The Demag crane’s existing controller was updated with a Siemens’ S7 PLC, facilitating fully automatic control via a SCADA system interface with the central Control Room. The refurbishment programme also included a bespoke 8 x 2 m Control Cabin to house the new Control Panel, which has an entrance porch, air conditioning and is pressurised to minimise the ingress of dust. The cabin, which is located near the roof of the store, also improves safety as technicians are no longer required to work on the system from the travelling crane bridge.
The Demag engineers were able to programme the new control system to operate the crane more efficiently and also provide an automatic synthetic (re-cycled) gypsum spreading function, a task that had to be done in manual control before.
Prior to the refurbishment the unreliability of the old control system meant that we often incurred waiting time charges from hauliers, typically in the last 3 months of 2014 these amounted to nearly £10k but these have now been all but eliminated in first quarter of 2015. Plus Production & Maintenance staffs time is now freed up to concentrate on other activities that help to improve productivity of the plant.