Damage to seeds by screw working bodies.

Seed damage caused by screw working bodies of agricultural machines reduces the seed quality and increases the total cost of crop production. This paper describes the impact interaction of a particle with screw flights when seeds are fed into the transportation zone. There are velocity dependences during the impact and reflection of seeds on the screw surface at the maximum distance of the radius from the screw rotation axis. The potential energy lost by seeds when interacting with screw flights is determined. The paper considers the way transporting the seed material by screw working bodies impacts seed damage. The potential energy accumulated after impact by the reflecting surface and the particle depends on the magnitude and direction of the falling velocity to the screw belt, the auger geometric and kinematic parameters (the screw diameter; the inclination angle of the helix to the screw axis and the angular velocity), as well as the physical and mechanical properties of the particle and the reflecting surface (recovery and friction coefficients). Previous studies have shown that the critical angular velocity of the screw flight depends on the screw casing and the reduction factor of the circumferential velocity. In turn, the reduction factor depends on the transported seed material and the geometric parameters of the screw. It is possible to diminish the destruction of the seed material due to impact interaction with the working surface of the screw by reducing the inclination angle of the screw flight α, the angular speed of the screw rotation ω and its radius R. It also requires direct the seed flow closer to the rotation center. Reducing injury to seeds during transportation in a screw device requires a higher critical angular velocity of the screw. To increase the working angular velocity of the screw without exceeding its threshold of critical angular velocity, it is advisable to use screws with a large pitch and polymer screws with a wider pitch.

Analysis of the interaction of seeds with a centrifugal disk working body of a chamber-type treater.

Presowing seed treatment is the first step in growing crops and obtaining a predicted high-quality yield. It plays a vital role in an integrated plant protection system. When treating seeds before sowing, it is crucial to avoid seed damage by the machine working bodies to obtain the planned harvest. For that reason, when designing new machines, it is necessary to exclude the use of auger working bodies and reduce the treatment speed. This paper analyzes the interaction of seeds with the working surfaces of centrifugal disk distribution bodies of pressown seed treatment machines. This paper considers the influence of geometric and kinematic factors on the distribution of particles at the outlet of the disk working body. Theoretical dependences that allow determining the relative speed of seed escape from the blades of a centrifugal disk have been obtained. An experimental plant allowing testing of the effectiveness of the proposed technical solution has been designed and manufactured. Theoretical and experimental studies allowed us to determine the conditions necessary for uniform chemical treatment of seeds and reduce the impact of centrifugal-type working bodies on seeds when treated with chemical or biological preparations before sowing.