Measuring Picking Force of Sunflower Seeds and Prediction of Reasonable Range of Air-Jet Parameters to Remove Sunflower Seeds from the Head

Abstract

To design a new machine which removes the seeds of sunflowers based on air-jet impingement, picking force of five varieties of sunflower seeds was measured. Effects of the loading rate, sunflower head’s diameter, the location of the seeds on the head and the number of the days after harvesting on picking force of seeds were studied. The tests were conducted 1, 2, 3 and 4 days after harvesting. Also theoretical air-jet impingement forces for four levels of nozzle diameter, four levels of jet temperature and eight levels of pressure of reservoir to which the jet were calculated. With the increase of the sunflower heads’ diameter and the loading rate from 50 to 150 g min^-1, the values of the picking force increased. With the increase of the distance between the location of the seeds and the center of the head, the values of the picking force decreased. Comparison between the experimental results and the theoretical calculations indicated that removing the sunflower seeds using nozzles with 2 mm is not possible. Also when the supply pressure is less than 5 bar, nozzles with a 4 mm diameter cannot be used to remove the sunflower seeds from the heads. The results indicate that using a nozzle with a diameter of 6 to 8 mm and pressure of 6 to 8 bar seems to be suitable for separating the seeds from SH, though more studies are required.