抄録
Misfeed of cell type metering device is considered to be caused by the following cases:
1) some dynamic conditions are not satisfied between the cell and the seed.
2) there is no seed on the cell. The purpose of this paper is to analyze the latter. It is assumed that the distribution of seeds on the seed plate is consisted in the conbination of a regular arrangement with a random one, and then the probability distribution function is derived as follows:
P(X)=e-(μ-κ)S{(μ-κ)S}X-κ⋅S/(X-κ⋅S+1)
where
P(X)=the probability that the constant area S on the seed plate contains exactly X seed grains.
X=number of seed grains in the constant area S on the seed plate.
S=the constant area on the seed plate.
μ=mean number of seed grains in unit area on the seed plate.
κ=number of seed grains in a regular arrangement of unit area on the seed plate.
Then this assumption was verified by comparing the theoretical distribution with practical one photographed under glass bottomed seed hopper, and the value of μ and κ were determined as μ=0.8 1, 2.60, 3.40, 5.02 and κ=0.43, 1.80, 2.00, 3.60 with maize, soybean, unhulled rice, and coated beet respectively.
It may be concluded that the accurate feed is carried out when the traced ring of the part of cell in which seed grain can drop occupies more area than 2.33cm2, 0.56cm2, 0.50cm2, 0.28cm2, the invers number of κ, with maize, soy bean, unhulled rice and coated beet respectively.
