After the last cane truck delivers sugar cane to the Mill, all factory equipment at Tower Hill must be taken apart, serviced and brought back to full working conditions in preparation for the next crop. Out of crop maintenance is crucial for any factory since necessary improvements, repairs and servicing are carried out to optimize in crop operations, increase overall factory efficiency and reduce mill downtime. At Belize Sugar Industries Limited, it is no different and personnel are organized in maintenance teams which are assigned to different sections of the factory such as the cane yard, mills, boiling house, other services and capital projects. These teams are managed and supervised by engineers who need to plan and set targets before the crop season ends and work to those targets during the out of crop period.
Once the crop starts, the factory equipment works continuously 24/7 with only a short stop for planned maintenance roughly every two weeks.
Mechanical maintenance during the Out of Crop period is very intensive. At the cane yard station, all the cane carriers are taken down; as the need arises, slats for these conveyors are
evaluated, repaired or replaced. All conveyor runways are also evaluated and refurbished. Cane levelers, cane knives and shredder rotors are also taken down and areas of severe wear and tear are built up with wear resistant welding, and these are re-assembled. At the milling station, all mill rollers and inter carriers are removed. Carriers are refurbished, drive systems are overhauled, and mill rollers are re-machined to meet the new mill settings. All lubrication and cooling lines are also taken down, cleaned, and refurbished. Mill headstocks are checked for proper alignment, and if required, are re-aligned as these have to withstand the tremendous pressure of cane crushing. Everything then has to be reinstalled, for proper operation during the crop.
The repairs at the boiling house area for any out of crop period are as intensive as the front end. All critical equipment,including pumps, sugar conveyors, juice heaters, clarifier, evaporators, sugar boiling, and sugar curing equipment are opened and thoroughly inspected for defects which are repaired or replaced. This is a critical requirement as any deviation from standards in this area could result in reduction of throughput at the milling station.
During the out of crop period, extensive electrical and instrumentation maintenance takes place to ensure all aspects of the milling plant are in full working conditions before the crop starts. This year, several repairs and upgrades are being carried out. The cane yard section is being integrated to the new control system at the mills to improve cane preparation and milling efficiency.
This improvement will increase efficiency for the mill and reduce overall electricity usage. The overall mills control system is also being upgraded to state of the art controls where the machine-human interface will be through the new monitors that will be displaying real time process signals which will increase mill performance and reliability during crop. The state of the art controls at mill also consist of a new Programmable Logic Controller (PLC) which will be the “Brain” of the milling process improving efficiency, lost time and operation.Twenty 350HP electric motors were also serviced and eleven were completely overhauled based on vibration analysis results to prevent motor failure and down time during crop.
The Control System for the continuous Vacuum Pan in the boiling house was also upgraded.