Effect of operating parameters on performance of an attrition-based apricot nut cracker

The operating parameters of an attrition-based apricot nut cracker were studied. The cracking unit of the machine consisted of two rollers made of hollow mild steel pipes punched along its circumferance to make a rough surface, with clearance between the rollers adjustable in order to accommodate apricot nuts of varying sizes. The operating parameters comprised of three levels each of roller speed and feed rate; and two levels of moisture content. The roller speed, feed rate and moisture content significantly affected the cracking efficiency, kernel damage and throughput capacity. Increasing the roller speed enhanced the kernel damage, whereas increasing the feed rate reduced the kernel damage. Roller speed and moisture content had a significant impact on un-cracked nuts, whereas, feed rate did not have significant impact on un-cracked nuts. Similarly, increasing roller speed and feed rate enhanced the throughput capacity. Increase in the moisture content decreased the cracking efficiency and enhanced the kernel damage. Empirical equations were formulated based on multiple linear models. Based on response surface methodology, roller speed of 394 mm.s⁻¹, moisture content of 8–10%, and feed rate of 45 kg.h⁻¹ were the optimal values for efficient operation of the apricot nut cracker. The response parameters cracking efficiency, kernel damage, un-cracked nut and throughput capacity were obtained as75.99%, 11.35%, 3.75% and 44.96 kg.h⁻¹, respectively.