CC BY
21
haykobiiii bichhk, 2000, bhn. 10.2
forestry joint-stock companies. We want to verify the hypothetical assumption (derived from the results of a pilot probe) that the necessary but not sufficient condition of correct work with environment-friendly technologies is the reflected environmental perception of the working place - forest environment. We would like to participate in the international research, educational and cultural programme "Carpathians" that is being organized by several foreign corporations. On this occasion we would like to co-operate with Ukrainian colleagues who would find out the social and environmental perception of forest environment by Ukrainian forest workers. The results would be used for international comparisons. I openly offer the co-operation in the project to ready colleagues from Lviv and Transcarpathian Ukraine. I ask the organizators of the programme "Carpathians" if they would kindly give their approval to this co-operation.
Literature
1.Krctsch, D., Crutchfield, RS., Rallachey, E.L.: Clovek vo spolocnosti (Man in the Society, in Slovak). Smena, Bratislava, 1962.
2. Podrabsky, J., Sedivy, V.: The Development oflnterrelations between Man and Nature. Paper of the symposium Foundations for different approaches, I.iblicc, 1989.
3. Sedivy, V.: ()draz ckologicke tovnovaliy v kultumicli zmenach - potenciaini ekologicke mi-grace (The Reflection of Fcological Balance in Cultural Changes - Potential Fnvironmental Migrations, in Czech). Proceedings of 3rd anthropological congress of Ales Hrdlicka: 151 .Humpolec, 1990.
4. Sedivy, V.: Ekologicka antropologie sestnactiletych hochu. Ncprijata habilitace ustavu antro-pologie. Pifrodovedecka fak. MU, Brno, 1994. (Fnvironmental Anthropology of Boys of Sixteen. Unaccepted liabilitation at the Institute of Anthropology, The Faculty of Natural Sciences, MU, Brno, 1994.)
Alois Skoupy, Radomir Klvac
BIODEGRADABLE OILS IN THE OPERATION OF PORTABLE FOREST MACHINES
Considerable amounts of oils used lor the lubrication of portable forest machines, particularly power saws, get into the forest environment. The paper brings some new findings concerning the dispersion of oils used for tlie lubrication of cutting parts of machines and a possibility of replacing mineral motor oils with biodegradable oils. Original methods used made it possible to perform a precise measurement of oil dispersion and to study the service life of engines in portable machines. The paper aims at a contribution to the knowledge of the related negative elfects of machines on the environment and on the health of machine operators.
Introduction
Lubrication of chains in power saws at a loss contributes to the introduction of oils into the natural environment. Expressed in absolute values, the amounts are so large that they can be considered an important element with a possible negative impact on the forest ecosystem, particularly contaminating the surface and underground waters. Some studies report as much as up to 60% of oil used for the lubrication of chains in power saws getting into the water either directly or through soil infiltration.
Research projects in Germany, Austria, Sweden and later also in the Czech Republic were aimed at a substitution of mineral lubricants with substances of natural origin and led to the development of vegetable-based technical oils. However, if these oils are to become a full-value replacement of mineral oils, their technical parameters have to be at least so good as those of mineral oils. This is why a research task was started in 1992 in cooperation with the CR Ministry of Agriculture, concerning the substitution of
2. JlicoeKcnjiyaTaui« 13 1
yKpaiHCbKHH gep'/KaBiiiiii mcoTexrnHHHH ymBepcHTeT
mineral oils with vegetable oils at the lubrication of two-stroke engines in portable machines. At the present time, the works continue within a Research Plan resolved at the Faculty of Forestry and Wood Technology, Mendel University of Agriculture and Forestry in Brno.
Methods
A radioindicator method was developed to assess the dispersion of oils, which makes it possible to quantify the oil dispersion immediately after cutting. There were altogether 42 measured cross-cuts made on Norway spruce and beech trees of diameters ranging from 10 to 30 cm with the use of three oils of different viscosity. Parameters studied included the absolute amount of oil on the soil surface, in the sawdust and on the processed timber. Expressed were mutual relations. The concentration of oils was measured also on the soil surface under the point of cutting.
Service life tests of 100 operating hours were drafted in order to assess the applicability of motor oils provided that the speed characteristics of engines be measured at the beginning and at the end of the life test so that any possible changes caused by the test can be detected. Characteristics expressing the course of torque, fuel consumption, inlet air temperature, engine temperature beneath the heater plug and atmospheric pressure were measured both in the course of the speed tests and in the course of the service life tests.
Calculations were then made of the average concentrations of CO, CO2 and IIC in exhaust gases, average temperature of engine beneath the heater plug and the average torque for all speed regimes and the fuel mixture used. The average values were used to express individual quantities as in standard CSN 302008. The following data were supplemented by calculation: corrected torque M,^ net output Pe; corrected net output Pc^; fuel consumption per hour G, and specific fuel consumption g«..
The tests were made on a Husqvama 242 power saw.
At the beginning the testing was made with the use of a Schenck W 40 whirling electric brake which was later replaced with a DC dynamometer Type DS 446-2V whose torque sensor is less sensitive to the occurrence of torsion harmonic oscillations. After several repeatedly made attempts at a suitable mechanical connection of the engine crankshaft with the measuring instrument the best suited combination was that of a flywheel, two flexible couplings and an inserted shaft with arbour supports (Fig. 1).
1 1-1 r
:: s ✓ • •
===~ir
ÜL ¿§
Fig. I. Diagramme of engine connection with the braking site: I - Engine of the Husqvama 242 petrol
saw; 2 - DC dynamometer DS 446-2/V; 3 - Propeller shaft; 4 - Flexible coupling; 5 - Dynamometer flange; 6 - Cross table; 7 - Flywheel; 8 - Electromagnetic device to control the throttle disk; 9 - Fuel feed
132
J3o 125-pii«m yiciiOJITy
haykobiiii bíchhk, 2000, bhn. 10.2
A device was designed for the service life test, which is capable of controlling the course of the life test to an inserted programme and to simultaneously record the measured values at all places where it is possible without any major problems. This is the way in which the throttle valve position was automatically controlled along with the speed of the braking site and moments for reading the following parameters: engine temperature, inlet air temperature, torque and rotations. The measured values were stored directly onto the computer hard disc.
The assessment of mechanical engine wear included the assessment of dimension changes, which can be affected by wear resulting from the use of different lubricating oils. The dimensions studied were as follows: some piston and cylinder diameters, piston ring joint backlash, spacing of heater plug electrodes, carbonization in the combustion space according to the methodology of Research Institute for Fuels and Lubricants (VUPM); the methodology is not the subject of this work (measurements were made by VUPM).
There were two oils gradually tested, each on a new engine of the Husqvama 242 power saw. In order to ensure comparable test conditions, one and the same carburetter was used for the two new engines, which was adjusted to manufacturer's instructions and sealed.
The measurements of speed characteristics were made in the range from 5 000 to 10 000 rpm with the individual measurements graduating by 500 rpm. The service life tests were arranged in such a way that the saw was operated at all times for 4 minutes at a full load of 8 500 rpm and then 2 minutes at 2 500 rpm. The oils evaluated were : OA M6A (mixture 1:25), BIO 2T/7 MIX (1:25), EUROL(l:66).
Results
The oil dispersion studies indicated that 55% to 85% of oil are caught in the sawdust, 3% to 15% of oil remain on the surface of timber being cut, and 10% to 35% of oil get onto the soil surface with the relative amount of oil on the soil surface decreasing with the increasing diameter of the cut timber although the absolute amount is naturally increasing (see examples in diagrammes Figs. 2 and 3).
3.00
3 260
■
8 E 2.00 •
!
i 1.50 .
H
1.00 i-
0.50 j
0.00 i
10 cm 15 an 20 an 25 an 30 an
8t*m <JI»m«tw
ooam8a qprimol bjquaker Fig. 2. The dependence of oil amount on the diameter of a Norway spruce specimen being cut
2. JlicocKcnjiyaTauin
133
haykobiiii bíchhk, 2000, bhn. 10.2
>
S N N
{ s r- N
i r ■f h v \ N
y \ -0 J ) '■v 1 y >
s \ J s
\ H J
_12___11____10_ _9_ _8__7_J_6_£__£_3__2___
Legend: 1 '
□ o.co- j 10.05- E^o.10. ■ «*>- R 0.25 - R 0.30
H°'3S' H0'40" H 0,45 - m 0.50 • H 0 55- ®m
Fig. 4. Soil surface oil concentration Table II: A verage and maximum soil surface oil concentrations
in g.cm"2
Norway spruce OA M6A PRIMOL QUAKER
Diameter Average Max. Average Max. Average Max.
10 cm 0.024 0.186 0.061 0.351 0.015 0.110
15 cm 0.039 0.301 0.061 0.408 0.021 0.114
20 cm 0.022 0.109 0.107 0.539 0.024 0.173
25 cm 0.044 0.237 0.083 0.458 0.024 0.146
30 cm 0.054 0.352' 0.099 0.669 0.055 0.292
Beech OA M6A PRIMOL QUAKER
Diameter Average Max. Average Max. Average Max.
10 cm 0.012 0.060 0.059 0.429 0.025 0.181
15 cm 0.022 0.191 0.061 0.410 0.030 0.142
20 cm 0.044 0.281 , 0.088 0.379 0.025 0.169
, 25 cm 0.041 0.383 0.088 0.629 0.029 0.191
30 cm 0.069 0.614 0.072 0.368 0.036 0.288
The results of motor oil testing were processed into tables and diagrammes. With regard to the permitted extent of this contribution, it is only several examples that are presented here. One of them is illustrated in Fig. 5 with the course of outputs. It showed that the maximum engine performance always exhibited a drop in the course of the life test. The drop was most significant with Eurol whilst the BIO 2T/7 MIX results were comparable with those of the OA M6A.
The measurements did not reveal any substantial differences between the respective oils. The results of measuring the carbonization deposits were evaluated to Methodology CZ 125 (511, 516) and recorded in tables and diagrammes (Fig. 6). The higher points the better result. In contrast, viewed from the point of carbonization the best of oils appeared to be Eurol that is not inclined to clogging of the exhaust port or to piston ring sticking.
The evaluation seems inconsistent only at the very First sight since some effects which were not subjected to study in the given methodology appeared to be decisive in the course of the life test. For example, Eurol fouled the carburetter sieve so that the end of the life test saw a considerably poorer fuel mixture. In the comparison with the initial measurements, Diagramme 4 shows the performance decrease at the medium speed and the increased performance, in contrast, at the higher speed.
2. JlicoeKciuiyarauin 135
haykobiiii bichhk, 2000, bhn. 10.2
that arise apparently due to the polymerization of these oils such as the clogging of carburetter sieve. In our opinion, the two methodologies are entirely original the statistic evaluation providing the repeatable results whose interpretation is a good basis for conclusions that can be used by manufacturers and users of oils as well as for farther research.
Acknowledgement
The work came into existence within the Research Project funded by the CR Ministry of Agriculture and within the Research Plan No.: J08/98:434100005 resolved by the Faculty of Forestry and Wood Technology, Mendel University of Agriculture and Forestry in Brno.
References
1. KLVAC, It.: I lodnoccnf biologicky odbouralclnycli oleju pro mazani motnrii motorovych pil -Mctoda ajejf overenf. /Assessing biologically degradable oils for the lubrication of engines in power saws -Method and its verification./|l)issertation|. Mendel University of Agriculture and Forestry in Brno, 1998, 53 p.
2. PECHLAK, B., SKOUPY, A., KIJKLA, .!.: Bilance uniku nwacfho oleje motorovych pil pomoci radioindikatoru. /rl"he balance of power saw lubricating oil leakage by means of radioindicator./ Radioisotopy,3l, 1990(3). pp. 145-154.
3. SKOUPY, A., ULRICH, R: Dispersion der Olabschcidung aus der Kettenschmierung von F.inmannmotorsagen. KWF Forsttechnische Informationen 1 Y 6050 K, 11,1994: pp. 121-132.
4. SKOUPY, A.: Biodegradable oils used in lubricating power saws. In: FORSITRISK, Conference IUFRO P3. 08, Munich 1994,6 p.
5. SKOUPY, A.: Rozptylanie oleju uzywanego do smamwania pil spalinowych. /Dispersion of used chain saw lubrication oil./ Polska Akademia Umictnosci, Prace komisii nauk rozlinczych, I'om 1, 1998, pp. 131-138.
6. SKOUPY, A., PF.CH1.AK, B„ PR1BYI,, F. and SFJKORA, P.: Zpusob zjiit'ovanf rozptylu oleju pouzfvariych k mazanf retezu motorovych pil pomocf radioindikatoru. /The method of detecting dispersion of oils used to lubricate power saw chains by means of radioindicator./ Acta Universitatis Agricul-turae (Brno), Series C (Facultas silviculturae), I.1X-I.X, 1990-1991, (1-4): pp. 89-100.
7. SKOUPY, A., PRIBYL, R., ULRICH, R. and STASTNY, H.: Nahrada mineralni'ho oleje olejem rostlinnym pri mazani dvoudobych motoru. /"lite substitution of mineral oil with vegetable oil at lubricating two-stroke engines./ |Study for CR Ministry of Agriculture|, Mendel University of Agriculture and Forestry in Bmo 1994,28 p.
8. SKOUPY, A., PRIBYL, F. and ULRICH, R.: Comparison of lubricating properties of some mineral and vegetable oils to lubricate chains ofchainsaws. Scientia Agriculturae Boliemoslovaca, 24 (XI J), 1992,(4): pp. 361-371.
9. SKOUPY, A.: The Wear Patterns of tlie Cutting Parts of Chain Saws Lubricated with Rape-seed Oil. Compared with tlie OA M6A Oil. I.esnictvf/Forestry/, 36, 1990 (11), pp. 959-968.
10. SKOUPY, A., PECHLAK, B. and SFJKORA, P.: A Contribution to Understanding of Oil Dispersion at tlie Work with a Chain Saw by Means of the Radiotracer Method. Lesnictvi /Forestry/, 36, 1990(11), pp. 937-946. _
Radomir Ulrich — Mendel University of Agriculture and Forestry, Brno, Czech Republic FOREST ROADS ON GROUNDS OF LOW BEARING CAPACITY 1. Methods of opeiiing-up the regions 1.1. The use of bark
Places characterized by grounds of poor bearing capacity which are permanently waterlogged and groundwater table is constantly at the level of soil surface can be passed only using the suitable type of a road with the corresponding type of roadway
2. JlicoeKcnjiyaiaiiin 137
