Tag Archives: pressure

xxx J. Čedík, J. Chyba, M. Pexa and S. Petrásek
Influence of shape of cutting tool on pressure conditions in workspace of mulcher with vertical axis of rotation
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Influence of shape of cutting tool on pressure conditions in workspace of mulcher with vertical axis of rotation

J. Čedík¹*, J. Chyba², M. Pexa¹ and S. Petrásek²

¹Czech University of Life Sciences, Faculty of Engineering, Department for Quality and Dependability of Machines, Kamýcká 129, CZ16521, Prague 6, Czech Republic
²Czech University of Life Sciences, Faculty of Engineering, Department of Agricultural Machines, Kamýcká 129, CZ16521, Prague 6, Czech Republic
*Correspondence: cedikj@tf.czu.cz

Abstract:

Nowadays there is laid great insistence on work efficiency improvement. This effort also affects the construction of mowers such as mulchers. Mulching with a vertical axis of rotation is very energy demanding work operation mainly, due to high energy losses. These energy losses, but also the quality of work, are influenced by the airflow and associated conditions of pressure inside the workspace of mulcher. Airflow in the workspace ensures repetitious contact of the truncated forage crops with the cutting edge tool and thus ensures crushing of aboveground parts of plants. The paper deals with the influence of the cutting tool shape on the mulcher’s inside workspace pressure conditions with the vertical axis of rotation. The influence of the trailing edge angle and rake angle on the pressure profile in the mulcher’s workspace with dependence on the rotor speed was examined. Measurements were performed on a laboratory single rotor mulcher model. It was found that in the mulcher’s workspace the vacuum is formed by virtue of the rotary movement of the cutting tools wherein the vacuum increases with rotor speed. The maximum measured vacuum was about 2.4 kPa and from the centre of the rotor towards its circumference almost linearly decreases. Furthermore, it was found that with decreasing trailing edge angle and with increasing rake angle the maximum vacuum decreases. When reducing the angle of the trailing edge from 45° to 25° led to reduction of vacuum of about 0.3 kPa (12.6%).

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298–306 F. Tan, I.S. Dalmıs and F. Koc
Effects of compaction pressure on silage fermentation in bunker silo
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Effects of compaction pressure on silage fermentation in bunker silo

F. Tan¹*, I.S. Dalmıs² and F. Koc³

¹University of Namık Kemal, Faculty of Agriculture, Department of Biosystem Engineering, Campus street, Number:1, TR59030 Tekırdag, Turkey
²University of Namık Kemal, Faculty of Corlu Engineering, Department of Mechanical Engineering, University 1, Sokak No:13, TR59860 Corlu/Tekirdag, Turkey
³University of Namık Kemal, Faculty of Agriculture, Department of Animal Science, Campus street, Number:1, 59030 Tekirdag, Turkey.
*Correspondence: ftan@nku.edu.tr

Abstract:

The aim of this research was to determine the effects of compaction pressure on maize silage fermentation under field conditions. The CAT 955 L type work machine was used for the compaction of the material. In this research, a pressure measurement system was developed to measure the compaction pressure in bunker silos. In bunker silos, 24 points for pressure and temperature measurement were identified. Chemical and microbiological analyzes were made by taking samples from each measurement point. The lowest temperature is measured in the back wall of the silo. There is a significant relationship between pressure and temperature. Pressure had a significant effect (P < 0.05) on silage fermentation. There was a significant correlation between regions in bunker silo and pressure (R2 = 0.914, P < 0.01).

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937-948 V. Bulgakov, S. Pilipaka, V. Adamchuk and J. Olt
Theory of motion of a material point along a plane curve with a constant pressure and velocity
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Theory of motion of a material point along a plane curve with a constant pressure and velocity

V. Bulgakov¹*, S. Pilipaka¹, V. Adamchuk² and J. Olt³

¹National University of Bioresources and Nature Management of Ukraine, 15 Heroiv Oborony St., 03041 Kyiv, Ukraine;
*Correspondence: vbulgakov@meta.ua
²National Scientific Centre ‘Institute for Agricultural Engineering and Electrification’ National Academy of Agrarian Sciences of Ukraine (NAASU), 11 Vokzalna St., Glevakha-1, Vasylkiv District, Kyiv Region, 08630, Ukraine
³Institute of Technology, Estonian University of Life Sciences, Kreutzwaldi 56, 51014 Tartu, Estonia; jyri.olt@emu.ee

Abstract:

The theory of motion of a material point has been developed, as a result of which plane curves as orthogonal sections of cylindrical surfaces with horizontal generators that provide a constant force of pressure during motion of a particle along a curve at a constant velocity have been found. New differential equations of motion of a material point along a plane trajectory on the surface of the cylinder have been made. Visualisation of the obtained results has been performed. Individual cases of motion where the force of pressure on the surface was bigger, smaller or equal to the weight of the particles, and where reaction of the surface equalled zero have been found. The given theory can be successfully used for design of mouldboard surfaces of cultivator machines.

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207-220 A. Jasinskas, G. Rutkauskas, A. Dravininkas and A. Mieldažys
Vibratory thickening of grass mass
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Vibratory thickening of grass mass

A. Jasinskas¹, G. Rutkauskas¹, A. Dravininkas¹ and A. Mieldažys²

¹ Institute of Agricultural Engineering of Lithuanian University of Agriculture,Raudondvaris, LT-54132 Kaunas reg., e-mail: aljas@mei.lt
² Lithuanian University of Agriculture,Kaunas-Akademija, LT-53361, e-mail: ifps.katedra@lzuu.lt

Abstract:

Flat surface inertia type vibrators in which the excitation force for thickening grass mass is received by turning the unbalanced mass were analyzed and evaluated. Directed and undirected action vibrators were manufactured and tested. The amplitude frequency characteristics of pressed grass mass were evaluated using a directed action grass mass pressing vibrator. It was concluded that resonant frequency depends essentially only on mass toughness qualities, and changes from 7.0 Hz when there is fodder goat’s rue (Galega orientalis Lam) mass of greater toughness, up to 15 Hz when thickening chopped maize mass of lesser toughness. The amplitude of grass mass pressure during resonance depends only on the mechanical resistance of the pressed mass. The amplitude of excitation power of goat’s rue and its mixes during resonance increased from 2.5 to 3 times but efficiency of mass pressure reduced. The calculated coefficients of pressure enhancement were equal to 5.5-5.8 when vibratory thickeners were used for pressing grass mass. The established repression of pressure on plant mass layer, while pressing mass on the surface and from the bottom of container, was 3.0-7.5 when using the directed action vibrator, and 4.8 when using the undirected action version. After evaluating the application of various tractors and vibratory grass mass thickeners for grass mass pressing it was found that in both cases the received efficiency rates of grass mass layer were similar. However, while using vibratory grass mass thickeners, these rates were even higher than using a wheeled tractor T-25A. The efficiency of mass thickening by centrifugal-directed action vibrator was evaluated by using an experimental trial. The results indicated that during vibratory thickening the grass layer was thickened intensely for 5-10 min. Therefore, it is advisable to use vibrators of this type for thickening grass layers of 0.4-0.6 m thickness. This vibrator resulted in good density of chopped maize – after 20 min of thickening (2×200 kg) the density of 510 kg/m3 was achieved and while thickening the first mix of 200 kg layer after 10 min 571 kg m-3 density was achieved. The densities of dry matter were 143 kg m-3 and 161 kg m-3 respectively. The investigation of the forage quality showed that it met the requirements of the highest-class silage.

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