AWF Wood Fibre Manufacturing Process

AWF wood fibre is produced from PEFC and Responsible Wood certified soft and hard wood chips that are sourced from local sawmills. The wood chips are first exposed to live steam at atmospheric pressure and heated to above 90˚C. It is then fed through a plug screw that removes most of the water including the wood sap, oils, and tannins. The plug screw then feeds the dehydrated chips into the pressurised preheater where it is treated for a minimum of 3 minutes at a temperature of more than 150˚C and pressure of more than 5 Bar. The heated chips are then fed through a ribbon screw into the center of a double disks Sunds defibrator where it is forced between two refiner plates no more than 2mm apart. The one plate remains stationary while the second rotate at 1420 rpm. The friction between the chips and the 1 meter diameter refiner plates separate the chips into individual fibre, small fibre bundles and fibre fractions. The refined wood fibres are forced to the outside of the refiner plates by the centrifugal force generated by the spinning refiner plate. The refined fibres are expelled from the refiner through a blow line that depressurise the fibre. The blow line expels the refined fibres into the hot air stream of a flash tube dryer with a minimum inlet temperature of 120˚C. In the dryer the fibres are (within 5 seconds) dried to 10-12% moisture and at the same time pneumatically transferred to a fibre bin where it cools down to room temperature. The fibre is then transferred on an enclosed belt conveyor over a continuous weighing scale and through a screw conveyor mechanically fed into the compression bagging machine. The bagging machine first weighs off the fibre into batches of 18kg and then discharges each fibre batch into a compression chamber. At this point additives like tacifiers and bio stimulants can be added through a batch feeding system. A combination of screw feeders and hydraulic ram compactors compress each fibre batch into a rectangular bale, in the process reducing bulk volume by about 600%. The compressed fibre bale is then expelled into a heat sealed pre formed, UV stabilised plastic bag and vacuum sealed. The sealed fibre bales are then palletised with 42 fibre bales to a pallet. The pallets are stretch wrapped and moved by forklift to storage and shipping. Liquid, powder and granular additives can be added into the process at various points.

The wood fibre produced through this process has an un compacted bulk density of 40-50kg/m3 and can absorb more than 11 times its own weight in water. The long fibres form a strong mechanically interlocking bond. The described manufacturing process produces a phytosanitary product.


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