Väderstad AB develops and sells agricultural machines in large parts of the world. Their segment includes many different types of machines, several of them being seed drills. The machine that this project focuses on is a seed drill that can plant numerous kinds of seeds, wheat and colza being among them. This machine is named Spirit.

The seed drill Spirit uses air currents to transport seeds from a container to the ground via a hose system. The velocity of the air must be high enough to eliminate the risk of seed getting trapped in the hose system. However, the high air velocity introduces the risk of seed bouncing out or being blown out of the furrow they are supposed to grow in. Therefore, this project’s purpose has been to solve this problem and thus improve the seed placement the seed drill possesses.

This paper consists of the theories and methods used to find a solution to this problem. A product development-process laid the foundation to this project in order to plan the project and generate solutions in a systematic way. After a problem analysis and analyzing competitors it became clear that a geometry in the end of the hose system could be used to separate air and seeds to reduce the seeds velocity and improve the seed placement. Several concepts have been modeled in CAD programs (Computer Aided Design) to later be analyzed in CFD programs (Computational Fluid Design), where air flows can be studied. Concepts has also been manufactured with 3D-printers in order to be evaluated with air currents and different kinds of seeds.

The usage of a product development process resulted in a final concept that uses the Coandă effect and the momentum of the seed in order to separate air and seed in an efficient way. Results from tests shows that the velocity of the seed are being reduced and that the air is being evacuated before the seed reaches the ground.