夏威夷果脱皮装置关键参数设计

Design on key parameters of macadamia nut peeling device

针对目前夏威夷果脱皮装置存在需先分级后脱皮、多是半自动、果径要求一致、效率低、合格率低、破损率高等缺点,研制一种螺旋对辊挤压式自适应脱皮装置。采集885个夏威夷果样本,测取带皮及脱皮果实三个方向上的果径,统计检验证实三径在0.05水平上均服从正态分布且相互之间在<0.0001水平上均显著相关,带皮果实圆度均值为0.9753-1.0486,确认夏威夷果的外观为球形。以实测的果径及分布为依据,脱皮装置设计成螺旋对辊弹性压块结构,采用球形果实模型对夏威夷果进行受力分析,获得脱皮装置的参数设计约束和受力平衡方程,设计脱皮辊的直径为76 mm、螺距为75 mm、有效长度为1100 mm、转速为400 r/min和间隙为4-12 mm,以及弹簧刚度为2.71 N/mm。性能试验表明,脱皮合格率均值达97.73%,脱皮破损率均值达1.13%,生产率均值达495.54 kg/h且与设计值高度吻合,生产率对作业质量的影响在0.05水平上不显著。综上,所研制脱皮装置的结构选型及参数设计合理有效,适合带皮果径24.21-38.97 mm的夏威夷果连续自动喂料的脱皮作业。

In view of the limitations of existing macadamia nut peeling machines,such as the first classification and then peeling,as well as the disadvantages such as semi-automation,the requirement of nut diameter consistency,low efficiency,low qualified rate,and high peeling damage rate,a new type of peeling machine based on double helix adaptive extrusion of roller type was developed.885 samples were used and the diameters in three directions of macadamia nuts with husk or peeled were measured.It was confirmed by statistical tests that the nut diameters of 3 directions obeyed normal distribution at 0.05 level and were correlated with each other significantly at 0.0001 level.The average roundness of nuts with skin was 0.9753-1.0486.The appearance of macadamia nut was spheroid.Based on the measured nut diameters and their distribution,the designed peeling device consisted of a structure of double helix rollers extrusion.Roundness nut model force analysis of the compression device was used on the macadamia nuts and the parameter design constraint and force balance equation were obtained.The final design of the peeling device was determined.The parameters of the two rollers were as follows:76 mm in diameter,75 mm in screw pitch,1100 mm in effective length,400 r/min in rotating speed,and 4-12 mm in the gap.In addition,the spring stiffness of the peeling device was 2.71 N/mm.The performance test showed that the qualified rate of peeling reached 97.73%,the rate of peeling damage was only 1.13%,and the average productivity was 495.54 kg/h,which was highly consistent with the design values.The effect of productivity on working quality was not significant at 0.05 level.All of the above results confirm that structure form selection and parameter design were reasonable and valid.While the diameter of macadamia nuts with skin was in the range of 24.21-38.97 mm,the developed peeling device was suitable for these macadamia nuts to perform peeling work with continuously automatic feedstock.