关键词: 夏威夷果, 脱皮装置, 脱皮辊, 挤压式, 自动喂料

Abstract: 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 0.000 1 level. The average roundness of nuts with skin was 0.975 3-1.048 6. 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, 1 100 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.

Key words: macadamia nut, peeling device, peeling roller, squeeze type, automatic feeding