Indagine sulla cippatura in Italia - Ivalsa - Cnr

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IL CALCOLO DEI COSTI Il Modulo Produttività 44 ne Inglese è contenuta nel file ChipCost.xls. Sulla sinistra del foglio è il Modulo Produttività. Qui l'utente deve inserire le informazioni riguardanti le proprie condizioni operative. Innanzitutto occorre indicare la potenza della cippatrice, scegliendo il valore appropriato sull'apposita finestra di selezione. Questa deve essere la potenza reale fornita alla cippatrice dal motore autonomo o dal trattore che la aziona. La potenza fornita alla cippatrice può essere inferiore alla potenza motore per diversi motivi. Un'eventuale gru incorporata consuma circa 20-30 kW, che devono essere sottratti dal valore inserito nel modello. Per le cippatrici azionate dal trattore, bisogna ricordare che la trasmissione della PTO assorbe un 10-20% della potenza totale. Le equazioni illustrate nel capitolo 4 sono state calcolate sulla base della potenza netta alla PTO, ed è questo il valore da inserire nel modello. Appena sotto, un'altra finestra di selezione chiede il peso del pezzo medio da cippare, espresso in kg tal quale. Il modello impedisce l'inserimento di valori troppo elevati in rapporto alle capacità della cippatrice. I nostri dati indicano che il peso del pezzo medio in kg raramente supera di 1.5 volte la potenza massima della cippatrice, espressa in kW (cfr. fig.18, Cap. 4). L'utente deve fare attenzione a non confondere il pezzo medio con il pezzo massimo - che può essere due volte più grande. Stimare il peso del pezzo medio che si prevede di cippare è più difficile di quanto Manutenzione e riparazioni (RM) (Depr*RMr)/SHY Consumo di combustibile, litri/ora (FC) 0.21 * P * Putil Costo del combustibile (F) FC * FP Consume di lubrificante, kg/ora (LC) 0.006 * P * Putil Costo del lubrificante (L) LC*LP Dove: RMr = Coefficiente di manutenzione e riparazione, espresso come % dell'ammortamento - in genere compreso tra 80 e 120 % SHY = Monte ore annuale P= Potenza massima del motore (kW) Putil = Coefficiente di utilizzazione della potenza massima disponibile (%) FP = Prezzo del combustibile al litro LP = Prezzo del lubrificante al kg Repair & maintenance (RM) (Depr*RMr)/SHY Fuel Consumption, liter/SH (FC) 0.21*P*Putil Fuel Cost (F) FC * FP Lubricant Consumption, kg/SH (LC) 0.006*P*Putil Lubricant Cost (L) LC*LP where: RMr = Repair and maintenance coefficient, as a % of Depreciation - generally between 80 and 120%. SHY = Scheduled hours/year P = Rated Engine Power (kW) Putil = Utilisation of rated engine power (%) FP = Fuel price, per liter LP = Lubricant price, per kg Figura 22 - Formule impiegate per calcolare i costi variabili. Figure 22 – Formulas used to compute operating costs. Indagine sulla cippatura in Italia • A survey of Italian chipping operations
COSTING THE OPTIONS the year (SHY) in order to get a cost per scheduled hour. The model will compute the hourly costs automatically, after the user inputs their own figures for the number of scheduled hours per day (SHD) and the number of working days per year (DY). Operating costs Operating costs per scheduled hour are calculated in fig. 22. Fuel and lubricant consumption are calculated on the basis of specific consumption at operating. They are assumed to be 0.21 liters of diesel and 0.006 kg of motor oil per kW-hour. As engines are actually run below rated power, real values are obtained by introducing a percent reduction, called “coefficient of power utilization “ (Putil). Using the model To access the programme, users must open the ChipCost.xls file with an appropriate version of Microsoft Excel – 95 or 97. The display will then show a worksheet containing a number of white boxes that need to be filled, before a chipping cost is returned. Labels on the worksheet are in English. An Italian version is contained in the ChipCostIt.xls file. On the left side of the worksheet is the Productivity Module. Here, users must enter details that describe their own working conditions. First, they select chipper power, in kW, in the designated list box. This is the actual power to the chipper, supplied by either the chipper’s own engine or that of the tractor. The chipper power may be somewhat less than engine power due to a number of factors. Integral loaders utilize some power - typically 20 to 30 kW - which must be deducted from the total engine power when entering a figure in the chipper power box. For tractor-powered chippers, only 80-90% of a tractor’s engine power is available at the PTO, due to losses in the drivetrain. Net PTO values were used to build the model, and these are the values to enter in the chipper power box. Just below, the user selects an average piece size, in green kg. The model prevents users from entering values that exceed the typical chipper capability. Our data indicate that the average piece size (kg) should not exceed 1.5 times the maximum power (kW) available to the chipper (cfr. fig. 18, Chapt. 4). Users should not mistake the average piece size for the maximum piece size - which is often twice as large. We understand that estimating the weight of the material that will be chipped might prove more difficult than it seems. Everyone knows what slash, tops and logs look like, but few can immediately figure out their average weight with any accuracy. For this reason, we report the average, minimum and maximum weights of the main types of material chipped during the trials (fig. 23). Users can refer to this table when selecting a piece size. Tipo di materiale Type of material Av. size Range Ramaglie Slash 17 3 – 53 Cimali Tops 96 25 - 217 Tronchi Logs 49 2 – 136 Piante intere Whole trees 123 10 - 414 Figura 23 - Peso medio, massimo e minimo per le diverse tipologie di materiale (kg tal quale). Figure 23 – Average, minumum and maximum weights of different types of material (green kg). The productivity module Indagine sulla cippatura in Italia • A survey of Italian chipping operations 45
Page 1 and 2: Consiglio Nazionale delle Ricerche
Page 3 and 4: CONTRIBUTI SCIENTIFICO-PRATICI PER
Page 5 and 6: CONTRIBUTI SCIENTIFICO-PRATICI PER
Page 7 and 8: Chapter 1 - Introduction ..........
Page 9 and 10: Breakdowns and repairs ............
Page 11 and 12: Chapter 1 - Introduction Foreword M
Page 13 and 14: Such model will allow fuel managers
Page 15 and 16: The survey includes 102 chipping tr
Page 17 and 18: many of the Italian operations. The
Page 19 and 20: government subsidies has pushed som
Page 21 and 22: variety of large machines as cannot
Page 23 and 24: observed in 15% of the cases only,
Page 25 and 26: The Machines and the Operators Our
Page 27 and 28: On the other hand, tractor-powered
Page 29 and 30: Foreign chippers are far less repre
Page 31 and 32: This would happen in hot-deck landi
Page 33 and 34: per, control all its functions and
Page 35 and 36: Statistical Analysis Figure 14 show
Page 37 and 38: the signal-to-noise ratio (Fig. 18)
Page 39 and 40: new station, too. We thought that t
Page 41: Chapter 5 - Costing the options fee
Page 45 and 46: A PRODUCTION MODEL Users must check
Page 47 and 48: A PRODUCTION MODEL ciation, investm
Page 49 and 50: A PRODUCTION MODEL to be working ev
Page 51 and 52: Chapter 6 - Practical Observations
Page 53 and 54: PRACTICAL OBSERVATIONS retractable
Page 55 and 56: Another new trend is in the resurge
Page 57 and 58: PRACTICAL OBSERVATIONS However, the
Page 59 and 60: duction of pulpwood. Disc chippers
Page 61 and 62: PRACTICAL OBSERVATIONS cantly strat
Page 63 and 64: led chipper. Those who opt for the
Page 65 and 66: E’ possibile montare una lama fis
Page 67 and 68: PRACTICAL OBSERVATIONS Disentanglin
Page 69 and 70: PRACTICAL OBSERVATIONS and he will
Page 71 and 72: tilted towards the chip spout to fa
Page 73 and 74: PRACTICAL OBSERVATIONS powered trai
Page 75 and 76: PRACTICAL OBSERVATIONS Indagine sul
Page 77 and 78: Chapter 7 - Quoted transportation c
Page 79 and 80: CONCLUSIONS Indagine sulla cippatur
Page 81 and 82: Landing 1 Truck 32,2 21 Tassignano
Page 83 and 84: Landing 2 Heap 1,0 77 Pradarena PR
Page 85 and 86: Bibliography ANDERSON A., 1989 - Br
Page 87 and 88: October. 2 p, 1 ref. GIBSON H.G., P
Page 89 and 90: quel prix? Informations Forêt n.4,
Page 91 and 92: vesting concept. In: Proceedings of
Page 93 and 94:
TAVOLA 1 - TABLE 1 3- Con una comun
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7 - Un tipico cantiere di cippatura
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TAVOLA 1 - TABLE 1 11 - Una cippatr
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TAVOLA 1 - TABLE 1 15 - Montagna al
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20 - Cantiere di cippatura in una f
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23 - Le occlusioni del collo d’oc
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27 - Le pinze dei caricatori sono m
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Indagine sulla cippatura in Italia
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Indagine sulla cippatura in Italia
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