Investigation of the Performance of Different Cleaning Devices in Maize Grain Harvesters Based on Field Tests

Highlights The effects of different factors on the performance of cleaning devices are investigated. The loss percentage is negatively correlated to the moisture content of maize grain. The cleaning performance is affected by the plant spacing and the ear mass of maize. The long-toothed scale screen has the best performance in throwing impurities. Abstract. The direct harvest of maize grain achieves high working efficiencies and low harvest costs; thus, direct harvest will become increasingly common for harvesting maize in the future. To investigate the loss percentage of maize grain (LPOMG) and the impurity percentage of maize grain (IPOMG) for harvesting in the northeast reclamation area in China, field tests were completed with various moisture contents of maize grain (MCOMGs), maize varieties, types of cleaning screens, and travel speeds of the harvesters. The results showed that the LPOMG of Xianda 205 maize with an MCOMG of 30.49% was the lowest at 0.37% and the IPOMG of Xianda 205 maize with an MCOMG of 22.62% was the lowest at 0.14% when the maize mixture was cleaned with the common scale screen in the S660 harvester. The LPOMG of Hayu 189 maize was the lowest at 0.19% when using the S660 harvester at a travel speed of 1.0 m s-1, and the IPOMG of Xianda 205 maize was the lowest at 0.28% when using the S660 harvester at a travel speed of 2.0 m s-1; the different varieties of maize mixtures were cleaned with the common scale screen. The LPOMG of Xianda 205 maize cleaned with the stepped woven screen was the lowest at 0.25% when using the GK100 harvester at a travel speed of 1.0 m s-1, and the IPOMG of Xianda 205 maize cleaned with the long-toothed scale screen was the lowest at 0.10% when using the 7088 harvester at a travel speed of 2.0 m s-1. This study provides a reference for selecting a suitable maize variety, type of screen, and the earliest harvest time for direct harvesting of maize grain.