Research Of Key Technology And Device Design For Peeling Water Chestnut

Water Chestnut,also known as eleocharis tuberosa,is a crop with homologous medicinal and food sources.It has medicinal values such as clearing heat and detoxifying,diuresis and swelling,as well as health functions such as dispelling dampness and phlegm,and reducing food and swelling.With the development of society,people are paying more and more attention to the diversity of food nutrition.As a characteristic food,water chestnuts are gradually entering people’s daily lives.The storage period of fresh water chestnut is short,in recent years,the canned products with water chestnut as raw material have developed rapidly,there are many safety and health problems in the process of peeling,so it is urgent to develop mature and reliable mechanical equipment for peeling water chestnut.Therefore,this paper carried out research on the key technology of water chestnut peeled,and designed a water chestnut peeled recycling integrated machine,the main content is as follows:（1）Measurement of geometric dimensions and material characteristics of water chestnuts.Using the water chestnut produced by Hubei Tuanfeng as a sample,the external dimensions and mechanical characteristics of the water chestnut were measured,and the results showed that the diameter of the water chestnutΦ₀ is 45.21 mm,effective meat thickness h₀ is 16.79 mm,water chestnut height h₁ is 26.34 mm,average moisture content is 84.92%,density is 1.06 g/cm³,Poisson’s ratio is 0.395,elastic modulus is 5.433 MPa,static and dynamic friction coefficients between water chestnuts are 0.656 and 0.489respectively,static and dynamic friction coefficients between water chestnut and stainless steel are 0.721 and 0.628,collision coefficient of restitution between water chestnut is 0.512,collision coefficient of restitution between water chestnut and stainless steel is 0.598.Conduct analysis on the mechanical characteristics of water chestnut cutting,design blades with different thicknesses and blade angles,and conduct shear tests on water chestnut.The results show that when the blade thickness is 2 mm and the blade angle is 20°,the shear force on water chestnut is the smallest;the pre cut water chestnuts were subjected to punching testing using a cylindrical knife.According to the force curve,it was found that the friction resistance between the knife and the flesh of the water chestnuts during punching was relatively high.These results provide a reference for the optimization of water chestnut peeler.（2）Research on parameter calibration of water chestnut discrete element simulation.The Ein Scan Pro handheld 3D scanner was used to obtain the point cloud data of the outer contour of water chestnut.After reverse modeling,particles were filled in the discrete element software,and the basic model was constructed based on the actual measured intrinsic parameters and basic contact parameters of water chestnut.Based on the Hertz Mindlin with bonding model to set up bonding bonds,and virtual calibration of bonding parameters was conducted based on the actual measurement of water chestnut shear force.The specific value of the significance parameter was obtained as the normal stiffness per unit area of 1.185×10⁸ N·m^-3,tangential stiffness per unit area 9.091×10⁷ N·m^-3,bonding radius 1.655 mm,other non-significant factors are particle contact radius 1.6 mm,critical normal stress 10.0×10⁶ Pa,critical tangential stress 10.0×10⁶ Pa.Conduct validation tests on the optimal parameter combination,and the results show that the calibrated parameters are accurate and reliable.To further validate the performance of the model under different working conditions,three types of blades,namely flat blade,concave blade,and convex blade,were designed to test water chestnuts.The results showed that the simulation and actual errors were small,and the shear force could be well predicted.The shear stress curve of water chestnut was derived by EDEM software,and the minimum shear force of the convex blade on water chestnut was obtained.（3）Design of an integrated machine for peeling and recycling water chestnuts.According to the process of artificial peeling,the mechanical peeling of water chestnut can be divided into two steps:at first,the bud and root were removed,then the side peel was removed.Based on this,an integrated machine for peeling and recycling water chestnut is designed,which includes a rotary blade type bud and root cutting device,a sorting device,a punching side peeling device,a pulp separating device and a collecting box,etc,the water chestnut can be peeled and recycled.Based on the theoretical design of simultaneous bud and root removal device,the mathematical model of bud root removal process of water chestnut was established,and the interaction of knife-water chestnut-disk was analyzed,and the structure and motion parameters were optimized;design the serrated rotary cutter,determine the parameter range through the theoretical analysis,provide the boundary condition for the follow-up test;design the flexible punching cutter,reduce the impact force in the working process,clear the work flow of each link,the whole machine can run automatically.（4）Experimental optimization of a rotating knife type synchronous removal device for water chestnut buds and roots.To reduce the resistance of root cutting,a serrated rotary cutting tool was proposed.Optimization experiments were conducted using EDEM discrete element software,and BBD response surface tests were conducted with factors such as serrated bottom length,tooth height,and cutting speed.The results showed that the cutting resistance was the smallest at speeds of 0.103 m/s,serrated bottom length of 5 mm,and tooth height of 15 mm.Compared with a flat blade knife,the optimized serrated cutting tool could achieve a resistance reduction effect of 23.29%;In response to the phenomenon of"oblique cutting"during the bud and root cutting of water chestnuts,an arc positioning hole was designed,and a test bench was built to analyze the working status of water chestnuts under different parameters.Orthogonal experiments were conducted with factors such as speed,arc length,and depth.It was found that when the working speed was 0.103m/s,the arc length of the positioning hole was 8.23 mm,and the arc depth was 5 mm,the height difference of water chestnuts oblique cutting reached the minimum value.（5）Overall performance evaluation.A single factor experiment was conducted on fresh water chestnuts,using the top and side damage rates of the flesh as indicators to analyze the impact of each factor on the results and determine the optimal parameter range.Through a two factor experiment,it was found that the top rod thrust has a significant impact on the top damage rate,while the punching shear force has a significant impact on the side damage rate;to reduce the damage of water chestnuts,response surface experiments were designed with water content,top rod thrust,and punching force as factors.The best working parameters were obtained as follows:the average value of moisture content was 82.72%,the thrust of the top rod was 17.341 N,and the punching force was125.6 N.At this time,the top damage rateη₁ was 14%and the side damage rateη₂ was12%,achieving the optimal effect within the factor range.Manual peeling was investigated and the performance of the whole machine was evaluated on this.The results show that the flesh retention rate of the machine after peeling is slightly lower than that of manual work,but the production efficiency is much higher than that of manual work.Moreover,the peeling is clean and thorough,and has high practical value.