Study On Technology And Device Of Maize Seed Fluid Hilling

Water shortage affects the sowing,emergence and yield of crop and it is one of the most important factors which limit the development of agriculture.Maize is one the main dry farming crops which is the most important source of food and forage,and it plays an essential role in agricultural production and natural economy.But it couldn't be sowed or with a low emergence rate for drought.The fluid hilling of maize was put forward in this study which combines the functions of water preserving agent,the watering bed sowing,the properties of the soaked seeds and fluid sowing.The mechanism and key technology of fluid hilling was studied which will contribute to the development and application of fluid sowing machine. The study explored a new way to resist drought,save water and ensure emergence rate.It is especially significant for northern China where lacks of water.1.According to the study on the physical and mechanical properties of soaked maize seeds, the test on viscosity,quantity and concentration of the mixed liquid of water preserving agent, the varying principle and diference of the parameters of soaked seed were revealed in this study and the suitable soaking time of maize seeds for fluid sowing was put forward for the first time which was16h～24h.And the parameters of soaked maize seeds,the type of water conserving agent utilized and the concentration of the sowing fluid were determined.2.The quadric orthogonal revolve test was carried out and the effect of the factors on the emergence of maize seed and growth was analyzed with Matlab and Excel.The mathematic model of fluid quantity and soil water content,the fluid concentration and soil water content were set up respectively.The applied fluid quantity and concentration for soil with different water content were determined.3.Dynamic analysis on the seeds in the fluid without agitation showed that the seeds of larger specific gravity and volume will settle in the fluid.The mechanism of pneumatic agitation and mixing was done and the mathematic model between the air quantity needed and the length,width of the seed chamber,the fluid height in the chamber and the required fluid velocity was put forward for the first time.The analysis and experiment showed that the required air quantity for unit volume of fluid was 250m~3/m~3·h～330m~3/m~3·h;4.The structure of maize fluid hilling device was determined and air blowing agitation was utilized to reduce the seeds settlement and damage.The pressure control system was set to maintain fluid metering pressure to avoid uneven seed metering caused by the decrease in height and pressure of the fluid in the chamber.Siphon principle was applied to solve the problem of seed settlement and the hammering function in the siphon tube was utilized to avoid seeds blocking during metering.The maize seed fluid metering device was designed based on solid model and simulation verification with Solidworks. 5.The principal innovation of this study are as following:①The varying law of the opening lash and the area of the metering valve was determined; the differential equation of the close of valve stem was established;the selecting principle for the opening area of the valve was determined by solving the equation of the closing time and opening area.②The mathematic model of the metering rate of fluid per hill to the diameter and the vertical distance between the inlet and outlet of the siphon metering tube,height of the fluid in the chamber,radius and angular velocity of the push wheel,the position of the push wheel and the valve stem,the parameters of the valve stem,the mass,diameter of the block ball,the elastic coefficient of the spring and the coefficient of the fluid metering rate.The analysis based on Matlab showed that the fluid metering rate could be varied by changing tube with different diameter or changing the revolutions of the push wheel.③The mathematic model of the increased air quantity needed to maintain stable fluid metering to the metering rate per hill,times of metering and dimension of the chamber was established.The air quantity needed per unit volume of fluid was 69.2m~3/m~3·h～149.5 m~3/m~3·h according to the formula.④The mathematic of the pull of spring was determined through analysis on the hammering impact in the siphon tube which will help to the design of the spring.6.The experiments results showed that the fluid metering device could realize maize seed fluid hilling.The percentage of hills with seeds of 2±1was 75%,seeds damage was 0,it had a larger percentage of empty hill,some of it was greater than 10%,the percentage of the permitted hill distance was 91.67%,the variable coefficient of the hill distance was 22.99%. The metering rate of fluid with a metering tube of 20mm can be adjusted between 70 ml～140ml.7.The economic analysis on the cost of fluid sowing,the increase of yield,the water saving and the development and application of the fluid sowing device showed that the fluid sowing is economical.