Tag Archives: rake angle

xxx J. Čedík, M. Pexa and R. Pražan
Effect of rake angle and cutting speed on energy demands of mulcher with vertical axis of rotation
Abstract |
Full text PDF (728 kB)

Effect of rake angle and cutting speed on energy demands of mulcher with vertical axis of rotation

J. Čedík¹*, M. Pexa¹ and R. Pražan²

¹Czech University of Life Sciences Prague, Faculty of Engineering, Department for Quality and Dependability of Machines, Kamýcká 129, CZ165 21, Prague 6, Czech Republic
²Research Institute of Agriculture Engineering, Drnovská 507, CZ161 01, Prague 6, Czech Republic
*Correspondence: cedikj@tf.czu.cz

Abstract:

The contribution deals with the reduction of agriculture energy demands. For maintenance and treatment of permanent grassland areas, areas left fallow and put to rest the mulching in combination with other workflows (mowing, grazing) is advantageous procedure. As conventional impact grass cutting and chopping is energy demanding procedure, it is proper to reduce the energy demands of such device. In the paper the effect of shape of cutting tool, particularly the rake angle, on energy demands of mulcher with vertical axis of rotation is studied. The effect of cutting speed on energy demands is also verified. The measurement was performed using mulcher MZ 6000 made by Bednar FMT Ltd. with working width of 6 m and three rotors. During the measurement the test rides using the cutting tools with different rake angle and cutting speeds of 105m s-1, 89 m s-1 and 79 m s-1 were performed. The rake angle of cutting tools were chosen 0°, 15° and 25°. The test area was pasture with permanent grassland. During the measurement the torque and power, transferred through PTO to the machine, fuel consumption and GPS coordinates were measured. From each test ride the samples of grass matter were taken in order to determine the yield and moisture content. It was found that increase of the rake angle up to 25° and decrease of the cutting speed resulted in decrease of the power requirement of the mulcher.

Key words:

, , , , ,




337–344 J. Čedík,, M. Pexa, J. Chyba, Z. Vondrášek and R. Pražan
Influence of blade shape on mulcher blade air resistance
Abstract |
Full text PDF (822 kB)

Influence of blade shape on mulcher blade air resistance

J. Čedík¹,*, M. Pexa¹, J. Chyba², Z. Vondrášek³ and R. Pražan⁴

¹Czech University of Life Sciences, Faculty of Engineering, Department for Quality
and Dependability of Machines, Kamycka 129, CZ 165 21 Prague 6, Czech Republic
²Czech University of Life Sciences, Faculty of Engineering, Department of Agricultural
Machines, Kamycka 129, CZ16521 Prague 6, Czech Republic
³Czech University of Life Sciences, Faculty of Engineering, Department of Electrical
Engineering and Automation, Kamycka 129, CZ 165 21, Prague 6, Czech Republic
⁴Research Institute of Agricultural Engineering, p.r.i., Drnovská 507,
CZ 161 01 Prague 6, Czech Republic
*Correspondence: cedikj@tf.czu.cz

Abstract:

Mulching is an energy-intensive agricultural operation. The efforts to reduce the energy intensity makes the designers explore new solutions which would reduce the energy intensity. One of the possibilities to reduce the energy intensity of mulching is to use a work tool of different shape. The paper introduces comparison of several shapes of blades intended for the mulcher with vertical axis of rotation, where especially the rake and cloth angle is changed. The measurement was performed by means of a laboratory model of a one mulcher rotor and in the field conditions where the mulcher Bednar MZ 6000 with a range of 6 m and three rotors had been used. The measurement was performed particularly from the point of view of the energy loss caused by drag of knives. The measurement done by means of the model of the mulcher has confirmed the hypothesis that larger cloth causes increased resistance of the mulcher and higher rake angle results in decreased mulcher resistance. However, larger cloth may contribute to better work quality in the field conditions.

Key words:

, , , , ,