Vibratory thickening of grass mass
¹ Institute of Agricultural Engineering of Lithuanian University of Agriculture,Raudondvaris, LT-54132 Kaunas reg., e-mail: email@example.com
² Lithuanian University of Agriculture,Kaunas-Akademija, LT-53361, e-mail: firstname.lastname@example.org
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.