FERTILISER SPREADER Russian patent published in 2013 - IPC A01C17/00 

FIELD: agriculture.

SUBSTANCE: spreader comprises a hopper with extension piece mounted on the frame, with safety screen and an opening in the bottom, and a diffuser with blades. The diffuser with blades is driven by the power take-off of the tractor. Under the opening in the bottom of the hopper there are two rotary valves. The valves are placed one above the other. In one of the valves two identical metering slots are made, displaced relative to each other around the axis of the spreader at an angle of 90°, the middle lines of which are given in polar coordinates with logarithmic spirals of the type $$\text{ρ}\left(\text{λ}\right)=\frac{\text{2R}}{\text{1}+\text{sin}\left(\phi \right)}\cdot \text{exp}\left[\frac{\text{1}-\text{sin}\left(\phi \right)}{\text{cos}\left(\phi \right)}\left(\text{θ}-\text{Mα}-\text{λ}\right)\right]\text{(1)}\text{,}$$ where R is outer radius of the disc, m; φ is friction angle of the particles on the blades and the disc, rad; Mα is the statistical expectation of throwing angle taken for the first spiral equal to 3π/4, for the second - 5π/4 rad; θ is angle between the absolute velocity and the radius-vector of the particle when descending from the blade, rad; λ is angular coordinate, rad; angle β between the tangent to the spiral and the radius-vector equal to $$\text{β}=\text{arccotg}\left(\frac{\text{1}-\text{sin}\phi }{\text{cos}\phi }\right)\text{(2)}\text{,}$$ where g is acceleration of gravity, m/s²; in the second rotary valve also two dispensing slots are made displaced relative to each other by 90°, the middles of which are given in polar coordinates by logarithmic spirals of the type $$\text{ρ}\left(\text{λ}\right)=\frac{\text{2R}}{\text{1}+\text{sin}\left(\phi \right)}\cdot \text{exp}\left[\frac{\text{1}-\text{sin}\left(\phi \right))}{\text{cos}\left(\phi \right)}\left(\text{θ}-\text{Mα}\right)\right]\cdot \text{exp}\left({\text{k}}_{\text{1}}\cdot \text{λ}\right)\text{(3)}\text{,}$$ where $${\text{k}}_{\text{1}}=\text{cotg}\left(\text{β}-\frac{\text{π}}{\text{2}}\right).$$ Above the rotary valves the cut off valve is mounted. The cut off valve is made and located so that in one of the extreme positions it completely covers the opening in the bottom of the hopper, and in the other it is out of its location.

EFFECT: increased uniformity of fertiliser distribution on the surface of the field with a minimum of operational adjustments.

3 cl, 7 dwg