Researchers determined the effect of chipper type, biomass type and blade wear on two chippers.Two different industrial chippers were operating in logging residues (tops and branches), thinning material and pulpwood. The drum chipper was a Jenz HEM 561, powered by a 246 kW (334 hp) Claas Xerion tractor, equipped with a crane and grapple for grabbing the material to be chipped. The disc chipper was a TS1200 powered by a 147 kW independent engine and mounted onto a John Deere 810D forwarder. The trials were carried out in birch, spruce, alder, pine and aspen in Sweden. There was no difference in the moisture content of the material, as it had all been left to dry over the summer. Other organisational and operating conditions were the same for both machines.
Some of the key results were as follows:
- The less powerful TS disc chipper used 28% less fuel per ton than the drum chipper.
- The disc chipper took 83% more time than the drum chipper to process one ton.
- The disc chipper took 35% more time per ton to process logging residues compared to small trees from thinning material.
- With the drum chipper in logging residues, 30% more time was used per tonne when operating with dull blades, and this also increased fuel consumption by 39%.
- The disc chipper produced the best chips from thinning material (pulpwood), but produced the highest amounts of oversized material when fed logging residues.
The study was titled “The effect of chipper type, biomass type and blade wear on productivity, fuel consumption and product quality” and was published in the Croatian Journal of Forest Engineering, Vol. 35(1) of 2014. The authors were C Nati, L Eliasson and R Spinelli. Access at http://www.crojfe.com/articles-789#790