Sowing element for precision pneumatic seed drills

1. A sowing element for a pneumatic seed drill which transports seed in a sowing advance direction and distributes the seed on a sowing ground, the sowing element comprising:

a selector disc for isolating the seed, the selector disc being rotatable about a rotation axis, and

a conduit for transporting the seed with an initial portion which is proximal to a position for removing the seed from the selector disc and an intermediate portion which extends in continuation of the initial portion and a terminal portion, wherein the conduit, at least in the initial portion and in the intermediate portion, is rectilinear and coaxial and has an axis which is located inside a plane which is perpendicular to the sowing ground and parallel with the sowing advance direction and in that an angle defined between a first plane which is perpendicular to the axis of the conduit in the rectilinear initial portion and rectilinear intermediate portion of the conduit and a second plane perpendicular to the rotation axis of the selector disc is between 60° and 80°.

2. The sowing element according to claim 1 , wherein the conduit in the initial portion and in the intermediate portion is orientated backwards with respect to the sowing advance direction.

3. The sowing element according to claim 1 , wherein the conduit at least in the initial portion and in the intermediate portion extends vertically during use when the sowing ground is substantially planar.

4. The sowing element according to claim 1 , wherein the angle is substantially equal to 75°.

5. The sowing element according to claim 1 , wherein the sowing element further comprises a pneumatic accelerator which is arranged along the conduit for transporting the seed.

6. The sowing element according to claim 5 , wherein the pneumatic accelerator is positioned between the intermediate portion and the terminal portion of the conduit.

7. The sowing element according to claim 6 , wherein the terminal portion has a length and the initial portion and the intermediate portion combine to have a total length that is greater than the length of the terminal portion.

8. The sowing element according to claim 7 , wherein the total length of the initial portion and the intermediate portion is twice the length of the terminal portion of the conduit.

9. The sowing element according to claim 5 , wherein the pneumatic accelerator includes a ring ejector.

10. The sowing element according to claim 9 , wherein the pneumatic accelerator is supplied with compressed air which is generated by a lobed positive-displacement compressor or by a compressor having a side-channel blower.

11. The sowing element according to claim 1 , wherein the terminal portion of the conduit for transporting the seed is rectilinear.

12. The sowing element according to claim 1 , wherein the terminal portion has a curvature.

13. The sowing element according to claim 12 , wherein the terminal portion deviates from the rectilinear initial and intermediate portions of the conduit for transporting the seed with a radius of curvature greater than 0.2 m.

14. The sowing element according to claim 1 , further comprising a connection element with respect to the pneumatic seed drill, wherein the connection element is configured in such a manner that the conduit, at least in the initial portion and in the intermediate portion, is vertical when the sowing element is connected to the pneumatic seed drill.

15. The pneumatic seed drill comprising a plurality of sowing elements according to claim 1 , the sowing elements being aligned in an alignment direction which is transverse to the sowing advance direction, the plane in which the axis of the conduit is located being perpendicular to the alignment direction, wherein the rotation axis of the selector disc of each sowing element is transverse to the alignment direction.

16. The pneumatic seed drill according to claim 15 , further comprising a support element for the sowing elements, the support element having an elongate form so as to define the alignment direction.

17. A sowing element for a pneumatic seed drill which transports seed in a sowing advance direction and distributes the seed on a sowing ground, the sowing element comprising:

a selector disc for isolating the seed, the selector disc being rotatable about a rotation axis;

a conduit for transporting the seed with an initial portion which is proximal to a position for removing the seed from the selector disc and an intermediate portion which extends in continuation of the initial portion and a terminal portion, wherein the terminal portion has a length and the initial portion and the intermediate portion combine to have a total length that is greater than the length of the terminal portion and wherein the conduit, at least in the initial portion and in the intermediate portion, is rectilinear and coaxial and has an axis which is located inside a plane which is perpendicular to the sowing ground and parallel with the sowing advance direction and in that an angle defined between a first plane which is perpendicular to the axis of the conduit in the rectilinear initial portion and rectilinear intermediate portion of the conduit and a second plane perpendicular to the rotation axis of the selector disc is between 60° and 80°;

a pneumatic accelerator positioned between the intermediate portion and the terminal portion of the conduit and arranged along the conduit for transporting the seed; and

a connection element with respect to the pneumatic seed drill, wherein the connection element is configured in such a manner that the conduit, at least in the initial portion and in the intermediate portion, is vertical when the sowing element is connected to the pneumatic seed drill.

18. The pneumatic seed drill comprising a plurality of sowing elements according to claim 17 .