Value Retention, Service Life, Use Intensity and Long-Term Productivity of Wood Chippers as Obtained from Contractor Records

Abstract

Acknowledging the absence of up-to-date empirical data on the value retention, service life and annual use of chipping machinery, in 2017 the authors surveyed the records kept by 50 contractors offering biomass chipping services. The machine fleet and operations in this survey could be taken as representative for most of Europe, where the biomass sector is well established and is facing further expansion. Data collection included the whole chipping unit, comprised of chipper, carrier and loader. Manually-fed units were excluded from the survey. The data pointed at a service life up to and exceeding 10,000 h and 10 years, which relieved any concerns about poor durability. Value retention was good, and may exceed that of other mainstream forestry equipment. Engine power was the main explanatory variable in any models to predict purchase price and productivity. The effect of this variable could explain most of the variability (>80%) in the purchase price and productivity data. Results also pointed at the essential equivalence in price and productivity between PTO-driven (i.e., tractor powered) and independent-engine chippers, once differences in engine power are accounted for. However, the distribution of purchase price between different components of the chipping unit was different between the two unit types, with the chipper accounting for a larger proportion of the total investment in independent-engine units. Machine power was also different, with most PTO-driven units being significantly smaller than independent-engine units, due to the limitations of existing tractors. Furthermore, half of the carriers assigned to a PTO-driven unit were subject to flexible use, i.e., they were not solely used for chipping work.

Selection of a chipper technology for small-scale operations - a Finnish case

“…The operational cost depends on all the incurred expenses when the chipper unit is actually operating. Conversely, the capital cost depends on the initial investment, the economic service life of the chipper unit, and the interest rate charged on borrowed capital; it is incurred whether or not the machine is working (Nurminen et al 2009;Ackerman et al 2014;Spinelli et al 2017). The investment risk exists because it is uncertain that the cost of the investment will be recovered and a profit gained (Virlics 2013).…”

Trends and Perspectives in the Design of Mobile Wood Chippers

“…Chippers do a very heavy job and are subject to high wear (Spinelli et al 2017). For this reason, regular maintenance is essential to avoid failures and achieve a long service life.…”

Computer Aided Modeling of Wood Chips Transport by Means of a Belt Conveyor with Use of Discrete Element Method

“…The basic ones include: a cylindrical chipper [1], a drum chipper [2], a disc chipper [3], a hammer chipper [4], or a spiral chipper [5]. Chippers for the industrial production of biomass, with high capacity (indicated in scientific publications on the power range from 130 kW to 900 kW [6]), have the wood chips outlet system based on the forced motion of the cutting mechanism [2,3,[7][8][9][10][11]. Chippers used on urban areas for tree care in parks, gardens, and by-road surfaces are low power machines (Figure 1).…”