Study On Pneumatic Spoon Type Peanut Precision Seed-metering Device

Peanuts have large seeds,thin testa and irregular shape.In the process of peanut planting,it is easy to have the problem of high damage rate of peanut seeds when only using mechanical seed metering device.However,only using pneumatic seed metering device has higher requirements for negative pressure stability and device sealing.When the air pressure is not stable,it is easy to miss seeding.In this paper,a pneumatic scoop type peanut precision metering device with auxiliary seed filling function is proposed,using the auxiliary seed filling function of the seed scoop can improve the single seed filling index of the seed metering device and achieve the purpose of single seed precision sowing.(1)Taking the common peanut seed “SILIHONG” in Xinjiang as the research object.The test of the material characteristics of the seed obtains the parameters of the peanut seed,such as the shape size,moisture content,100 grain weight,natural repose angle,sliding friction angle,etc.which provides the theoretical basis for the design of the seed metering device.(2)The structural composition and working principle of the seed meter are explained and the key components of the seed meter are designed.FLUENT simulation shows that the different spoons,suction hole diameters and suction holes affects flow field of the negative pressure area of the seed tray and shows that when the shape of the spoon is a ladder,the suction hole diameter is 5.1 mm and the number of suction holes is 10,the flow field distribution in the negative pressure area of the seed metering device is the most even.(3)The simulation test which accorded to the design method of quadratic orthogonal rotation combined test and took the opening angle of seed spoon,the depth of seed spoon and the rotation speed of seed metering device as the test factors of seed filling performance of seed spoon was carried out by using EDEM software.The test result showed that the main and secondary factors influencing the single seed filling index,the multiple-seed filling index and the missing seed filling index of seed spoon were the depth of seed spoon,the rotation speed of seed metering device and the opening angle of seed spoon relatively and showed that the actual seed filling effect of seed metering device is the best when the opening angle of seed scoop is 50 °,the depth of seed scoop is 6.7 mm,and the rotation speed of seed tray is 28 r/min.At the same time,the single seed filling index is 94.34%.(4)The secondary orthogonal rotation center combined test design method which took the rotation speed(18-43.2 r/min)and negative pressure(4-8 kPa)as the test factors and the qualified index,the multipleseeding index and the missed seeding index as the performance indexes was used to carry out the seed metering device bench test.The test results showed that the seed metering performance(the qualified index is 96.75%,the multiple-seeding index is 2.22%,the missed seeding index is 1.03%)of seed metering device is the best when the rotation speed of seed metering device is 28 r/min and the negative pressure is 7 kPa.The test index of seed metering device is better than the national standard precision seeding requirements which can achieve effective seed metering.