Woodchipper

A wood chip Harvester is a combination of wood harvesting and a mobile chipper. Harvesters are mainly used in forest management in the coniferous forest and cut the trees to be taken into industrially usable lengths. Mobile chipper shred after not marketable scrap wood to wood chips, from which particleboard or pulp produced or bioenergy is produced by combustion. The chips Harvester combines both operations.

History and Development

The first machines of this type were the early 90s by the Danish Forestry Brand Silvatec. These machines were built exclusively for thinning young coniferous stands and were initially only with a wooden gripper mounted on a seven meter long crane, equipped to supply manually felled whole trees to the hacker. Some models had a felling head, with which it was possible to cut down trees in the immediate work area of the machine. A reappraisal of the tree into different log lengths but was just as impossible as the limbing. The maximum possible Hackgutdurchmesser was 28 cm. 1993 developed Greß J. and U. Jacobsen a first machine, which was equipped with a harvester head for the processing of fixed lengths and at the same time had a powerful large-scale hacker. Features of this machine were:

  • Labor and the turning range of the machine = 270 ° ( Silvatec = 60 °)
  • Max. Hackgutdurchmesser = 65 × 50 cm ( Silvatec = 28 cm)
  • Compact design (length 7.8 m - 9.8 m = Silvatec, Volvo BM = 11.30 m )
  • In production data comparable to the single Harvesters and mobile chipper 2 chips Harvester
  • Manual preparations were no longer necessary
  • Roundwood production and utilization of wood residue in a single pass
  • Can also be used in hardwood forests

Comparison of ways of working

In order to achieve the same results in harvesting with conventional machines, at least three machines are required. The harvester fells the tree and sawed him into usable lengths, the forwarder collects the timber and transports it to the forest road and the mobile chipper then moves repeatedly through the skid trails to chop wood residue or crown material. When wood chips Harvester skip this step, because during the workup accumulating residual wood is cut immediately. The transport of wood chips from harvesters for provided on the forest road Absetzcontainer takes a forwarder with Tipping.

During the trip to the forest road produced valuable timber was charged. This so-called " shuttle " was equipped with a hook lift, which allowed a quick change of container and Runge frame for shifting of our short wood. In multiple long-term test by renowned institutions such as forestry or KWF LWF University of Munich, this technology has been classified as particularly gentle ground wood harvesting methods, as the machine had traveled only once each working alley. In addition, only two specialized machines were required to produce what operating and material costs. This chips Harvester was used between 1995 and 2000 in different regions of Germany, the Netherlands and briefly also in France and produced in Switzerland today wood chips to supply local small cogeneration plants. A total of ten machines in various models in Sweden (1 ), Estonia ( 6 ), Denmark ( 1 ), Switzerland (1) and Germany ( 1) were built according to this idea, ran or are still active.

Disadvantages of the system

  • Necessary high logistic effort, both in the planning phase as well as in the daily operation
  • Transportable in this design, only with special low loader
  • Used by a lack of opportunities for alignment of machinery ( crane tilt, Boggielift ) only in the lowlands or leichtbergigen jobs

Developments

In addition to the Danish manufacturer Silvatec (machine model CH 878 ) has (formerly Valmet ) brought out with the Finnish forest machine manufacturer Komatsu Valmet 801 Combi a machine on the market that works on the same technology. Meanwhile, the production of both machines was discontinued due to lack of demand again. The storm damage in recent years called for United hackers who can handle much wood as possible in a short time. Named manufacturers today focus on special Harvester aggregates, which allows the removal of several trees in one operation. Other known manufacturers sold on bundler. These special structures for forwarders collect residual wood and crown material together from the impact area and squeeze it to transport just bundles, which are then burned in biomass power plants for energy.

Harvester (forestry)
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