Analysis And Tests Of Screening Characteristics Influencing Factors Of 3-DOF Multi-dimensional Vibrating Screen For Fly Maggots And Sputum

In order to meet the market consumption requirements,pig industry in China is developing in the direction of scale and intensification.The large amount of livestock and poultry manure produced has caused pollution to the environment,which seriously endangered human health.The accompanying method of fly maggots to treat livestock manure has gradually gained application in the livestock and poultry industry because of its low cost and efficient consumption of livestock manure.However,the use of fly maggots to treat livestock manure has not been rapidly developed due to the lack of rapid and controllable separation techniques for sputum and fly maggots.Therefore,it is extremely urgent to design a fast,controllable and automated separation device for sputum and fly maggots.Our research group have proposed a 1T2 R parallel multi-dimensional vibrating screen for the rapid and effective separation of sputum and fly maggots,and it has been initially proved that the parallel vibrating screening technology can achieve rapid and effective separation of sputum and fly maggots.Based on the previous measurement of the physical parameters of the fly maggot,this paper has further measured the main physical parameters of sputum by experiment,and established some particle models conforming to the actual situation in the EDEM software,and performs orthogonal analysis of factors affecting the screening efficiency of the prototype,The specific content can be summarized as follows:1.Determination of the physical parameters of sputum.Taking the mixture of fly maggots and remaining livestock and poultry manure called sputum as the research object,the appearance,size and proportion,water content,density and other parameters have been obtained through physical tests.The shear strength,internal friction coefficient,cohesive force between sputum,internal friction angle and elastic modulus have been obtained by physical property tests and image method respectively.The Poisson's ratio,shear modulus and bond radius of sputum was calculated by empirical formula.The bonding parameters of sputum,including critical normal stress,critical tangential stress,normal stiffness and tangential stiffness,have been obtainedby relevant literature and debugging of simulation in EDEM.Finally,other simulation parameters for sputum also have been obtained according to the references.2.The factor analysis of the 3-DOF multi-dimensional vibrating screen for separating fly maggots from sputum based on DEM.Based on the simplified model of the main parallel structure of the multi-dimensional vibrating screen,the three kinds of sputum models and two species of fly maggots models established in EDEM,the32 groups of experimental program obtained by the orthogonal experimental design method were simulated in EDEM,the results showed that the vibration frequency,Z-axis amplitude,X-axis swing amplitude and Y-axis swing amplitude have the most significant influence on the screening result,their best values were 5.5Hz,10 mm,8°,7°respectively.The ratio and water content have little effect on the screening results,but they still have the best value,which were 17.5% and 60% respectively.3.Structural optimization and kinematics analysis of the main structure of the3-DOF multi-dimensional vibrating screen for separating fly maggots from sputum.Based on the optimization of the existing multi-dimensional vibrating screen,the new main structure of the vibrating screen obtained was taken as the research object to carry out the theoretical analysis of the displacement,velocity and acceleration,and the feasibility of the main structure was verified by the simulation results in ADAM software.4.The structure statics and natural frequency analysis of 3-DOF multi-dimensional vibrating screen for separating fly maggots from sputum.The main structure of the multi-dimensional vibrating screen was taken as the research object,the result of the static analysis proved that the displacement deformation and the maximum stress of the main parallel structure can meet the structural requirements.The result of the modal analysis proved that the working frequency of the main structure was far from its inherent frequency,it can effectively avoid the resonance phenomenon in the working process.The result of the harmonic response analysis proved that the fragile location of the main structure was located at the bottom center position and the upper midpoint on the right side of the vibrating screen frame,but the maximum displacement is still within the allowable range.5.The sieving tests of the 3-DOF multi-dimensional vibrating screen for separating fly maggots from sputum.The design of the feeding device and the discharging device was completed based on the main parallel structure of the multi-dimensional vibrating screen,and the control system design and debugging of the principle prototype had been carried out.Twelve groups of programs with good simulation results was tested on prototype,and the scheme A4B1C2D4E3F4 was further proved to be the best choice.The significant test of the influencing factors of the sieve screening efficiency have been carried out to further verify the vibration frequency,Z-axis amplitude,X-axis swing amplitude and Y-axis swing amplitude was most significant,and the ratio and moisture content have little effect on the screening results.