Is Double Threshing c/w a bunch crusher an effective way to reduce USB? Can FFB splitter make Double Threshing redundant?
Background
After introduction of weevil was into Malaysia, the FFB bunch formation became so compact that conventional sterilisation with single threshing could no more effectively striped clean the sterilised bunches. Double threshing c/w a bunch crusher was introduced out of that to reduce the unstripped bunches, USB.
How is the performance of double threshing?
With double threshing, it is not uncommon to notice that mill tends to overload the first thresher very often and many 2-line mills are putting one single third thresher for the second threshing of thresher 1 & 2 combined. Correct if I am wrong, most of the mills are having 6~8% of USB ex-First threshing, achieving 2~4% USB after second threshing. Mills normally stationed one worker to recycle these USB. On closer observation of these recycled bunches, it may not be surprised to find that most of these unstripped bunches are Black/Unripe bunches.
With the enforcement of zero unripe FFB and introduction of FFB Splitter before sterilisation, do you agree that we Engineers should revisit this “double threshing c/w bunch crusher” station and rationalise its effectiveness?