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Articles by Robert Prinz

Category : Research article

article id 165, category Research article
Yrjö Nuutinen, Kari Väätäinen, Antti Asikainen, Robert Prinz, Jaakko Heinonen. (2010). Operational efficiency and damage to sawlogs by feed rollers of the harvester head. Silva Fennica vol. 44 no. 1 article id 165. https://doi.org/10.14214/sf.165
Keywords: productivity; single grip harvester; feed roller; timber damages; work study
Abstract | View details | Full text in PDF | Author Info
In mechanical cutting, deep damage caused by feed rollers can reduce the yield of good quality timber for the sawmill and plywood industries. Additionally the feeding and energy efficiency of feed rollers are important for the profitability of harvester cutting. The objectives of this study were to compare the damages to sawlogs, as well as the time and fuel consumption of stem feeding with six different steel feed rollers during the processing of stems using a single grip harvester. This study tested two rollers with big spikes, two rollers with small spikes, one roller with studs in v-angle and one roller with adaptable steel plates in the ring of the roller. A highly detailed, and accurate processing and fuel consumption projection was recorded using the harvester’s automated data collector on a log and stem level. The roller adaptable plate averaged, for unbarked sawlogs, the lowest damages of 3.7 mm. While the damages of the roller with big spikes were the deepest with an average of 7.8 mm. For medium stems, volume of 0.35 m3, the range of differences between the maximum and minimum effective feeding time per roller was 6–19%, which would increase the effective time consumption of cutting by 1–3%. Corresponding differences in fuel consumption during total stem processing were in the range of 7–15%. According to this study it can be concluded that the traditional rollers with spikes were most effective in processing and fuel consumption, but at the same time they caused the deepest damages to the sawlogs. The roller type with adaptable steel plates was the most effective for small stems, additionally it also caused the least damage to the sawlogs.
  • Nuutinen, Finnish Forest Research Institute, Joensuu Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: yrjo.nuutinen@metla.fi (email)
  • Väätäinen, Finnish Forest Research Institute, Joensuu Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: kv@nn.fi
  • Asikainen, Finnish Forest Research Institute, Joensuu Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: aa@nn.fi
  • Prinz, Finnish Forest Research Institute, Joensuu Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: rp@nn.fi
  • Heinonen, Finnish Forest Research Institute, Joensuu Research Unit, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: jh@nn.fi

Category : Research note

article id 60, category Research note
Dominik Röser, Blas Mola-Yudego, Robert Prinz, Beatrice Emer, Lauri Sikanen. (2012). Chipping operations and efficiency in different operational environments. Silva Fennica vol. 46 no. 2 article id 60. https://doi.org/10.14214/sf.60
Keywords: wood-fuel logistics; forest machinery; bioenergy supply
Abstract | View details | Full text in PDF | Author Info
This research analyses the productivity of energy wood chipping operations at several sites in Austria and Finland. The aim of the work is to examine the differences in productivity and the effects of the operational environment for the chipping of bioenergy at the roadside. Furthermore, the study quantifies the effects of different variables such as forest energy assortments, tree species, sieve size and machines on the overall productivity of chipping. The results revealed that there are significant differences in the chipping productivity in Austria and Finland which are largely based on the use of different sieve sizes. Furthermore, the different operational environments in both countries, as well as the characteristics of the raw material also seem to have an effect on productivity. In order to improve the chipping productivity, particularly in Central European conditions, all relevant stakeholders need to work jointly to find solutions that will allow a greater variation of chip size. Furthermore, in the future more consideration has to be given to the close interlinkage between the chipper, crane and grapple. As a result, investments costs can be optimized and operational costs and stress on the machines reduced.
  • Röser, Finnish Forest Research Institute, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: dominik.roser@metla.fi (email)
  • Mola-Yudego, University of Eastern Finland, School of Forest Sciences, Joensuu, Finland E-mail: bmy@nn.fi
  • Prinz, Finnish Forest Research Institute, P.O. Box 68, FI-80101 Joensuu, Finland E-mail: rp@nn.fi
  • Emer, University of Padova, Department of Land, Agriculture and Forest Systems, Legnaro (PD), Italy E-mail: be@nn.it
  • Sikanen, University of Eastern Finland, School of Forest Sciences, Joensuu, Finland E-mail: ls@nn.fi

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