Study of Performance Parameters of Threshing Unit in a Single Plant Thresher

Problem statement: The rice is the one of important crop in the word which is cultivated at the extensive area of Iran. Yield of crop is a factor which is investigated in the breading researches. Usually, for threshing of crops at these studies, single plant thresher is used. Approach: In this study, the threshing unit of a type of single plant thresher (Almaco SPT-SEX model) was evaluated. The effects of drum speed, crop moisture content and variety were investigated on the threshing loss, damaged grain percent and power requirements of threshing unit. Tests were arranged as a split- split plot fitted into randomized completed block with three replications. To compare the means, Duncan's Multiple Range Test was used. Results: Results showed that the effects of variety on the damaged grains percent and power requirement of the threshing unit were significant at probability level of 1% and 5%, respectively. The effect of crop moisture content was significant at probability level of 1% on the threshing loss and power requirement. Conclusion/Recommendation: With increasing of drum speed at all varieties, threshing loss decreased. At all drum speed levels, by increasing drum speed, damaged grains percent increased. At each drum speed, the mean of power requirement at wet condition of paddy was significantly higher than dry condition of paddy.