Design And Experimental Study Of A Separating Device For Living Earthworms

Industrialized earthworm culture mode is the development trend of earthworm culture in the future.The existing in vivo earthworm sorting device has some problems,such as low sorting rate and slow sorting speed,which can not meet the needs of production.Moreover,there is still a big gap in the study of screening parameters of earthworm sorting device.On the basis of the existing separation devices,this paper designs and studies two kinds of separation devices of earthworms,vibrant type and drum type,aiming at the industrialized earthworm breeding mode.The specific research contents are as follows:Based on the analysis of the current situation of earthworm sorting research at home and abroad,a frame-type vibrating earthworm sorting device was innovatively proposed according to the material characteristics of earthworm culture medium in factory farming mode.Vibration screening mechanism was studied by establishing particle motion model and screening probability model.On the basis of studying screening mechanism,screening parameters were analyzed and calculated.Using the finite element software Ansys Workbench,the dynamic simulation of the screen body,which is an important part of the vibration separator,is carried out from three aspects: modal analysis,harmonic response analysis and transient dynamic analysis,and the structure design of the screen body is determined.A prototype of vibrating earthworm sorting device was made and experimental study was carried out.Two-factor five-level full-factor test on exciting force and screen inclination was carried out on the earthworm culture medium with 54.58% moisture content.The influence of exciting force and screen inclination angle on screening rate was analyzed through experiments.The optimum screening parameter design of vibrating earthworm sorting device was determined: exciting force was 6.5kN,screen inclination angle was 10.The screening rate can reach 58.525% and the screening speed can reach 1.295 t/h.According to the screening test of low humidity earthworm culture medium,the vibrating earthworm sorting device has better screening effect for the earthworm culture medium with low moisture content.For the earthworm culture medium with 35.64% moisture content,the screening rate can reach 70.82%.The adhesion ball model of earthworm excrement was established,and the mechanism of adhesion ball of earthworm excrement during screening was analyzed.The movement model of particles in the drum was established.The mechanism of drum screening was studied based on the adhesion ball mechanism of earthworm excrement.On this basis,the screening parameters of the drum separator are analyzed,and the important parts and transmission system of the separator are designed.The virtual prototype of the drum separator is simulated by using the virtual prototype analysis software Adams,and the static simulation of the driving shaft,an important part of the transmission system,is carried out by using the finite element software Ansys Workbench.The prototype of the drum separator is made and tested.The orthogonal experiment of three factors and four levels about the drum speed,the drum inclination angle and the feed speed is designed.The changing trend of the screening rate and the earthworm separation rate at different levels of the screening parameters was obtained through experiments.The optimum design of the screening parameters of the drum-type separating device was determined.When the rotating speed of the drum was 18 r/min,the inclination angle of the drum was 7 degrees and the feeding speed was 0.6 t/h,the earthworm separation rate could reach 91.89%.The earthworms obtained by the separation had good activity and could meet the requirements of the earthworm separation.