Design and Key Parameter Optimization of Conic Roller Shelling Device Based on Walnut Moisture-Regulating Treatments

Abstract

The quality of walnuts deteriorates owing to the poor quality of the shelling equipment. The improvement of shelling quality is urgently required for walnut processing. In this study, systematic research was carried out on the changes in walnut mechanical properties, mechanical model of walnut shelling, and the key parameters of the equipment. The key parameters were determined as the angles of the shelling conic roller (X1), speeds of the shelling conic roller (X2), clearance between the shelling conic roller and the static roller (X3), and the moisture content of walnuts (X4). The Box–Behnken design method was used for the experimental design, an analysis of variance was applied to determine the graded significance of each variable on the rate of high-quality kernel (RHQK) and rate of shell rushing (RSC), and the multi-objective optimization method was used to obtain the optimal parameters for RHQK and RSC. The ranking of factors affecting RHQK and RSC were: (X3) > (X4) > (X2) > (X1) for RHQK, and (X2) > (X3) > (X4) > (X1) for RSC. The ranks of significant interactive effects among the factors were as follows: (X1 X2) > (X2 X3) for RHQK and (X2 X3) > (X3 X4) > (X2 X4) for RSC. The multi-objective optimization results showed that the optimal combination was X1 = 15.83°, X2 = 17.93 rpm, X3 = 45 mm, and X4 = 9.5%, yielding RHQK = 84.54%, and RSC = 99.15%. The verification test of the optimal results further illustrates the accuracy of the optimization. The obtained results showed that the quality of walnut shelling can be improved by adjusting the moisture content of walnuts and optimizing key parameters of the equipment. This method also represents a potential solution for improving the shelling quality of other nuts.

Design and Performance Evaluation of a Multi-Point Extrusion Walnut Cracking Device

“…In the harvest season of 2021, fresh-harvested walnuts (Juglans regia L.) were collected from the Wensu Walnut Experimental Station (latitude: 41 • 27 67 N, longitude: 80 • 24 17 E, and at a 1056 m altitude), Xinjiang, China. A moderate walnut moisture content is known to improve the quality of cracking [17]. Thus, according to our previous study [18], walnut shells with a moisture content range of 7-9% and kernels with a moisture content range of 10-13% were used in the walnut cracking experiments.…”

“…The length (L), width (W), and thickness (T) [17] of 200 randomly selected walnuts were measured (Figure 2) using a DELI DL91150 digital caliper (DELI Group Co., Ltd., Ningbo, China) with an accuracy of 0.01 mm. To classify the walnuts more accurately, the equivalent diameter of walnut samples was calculated based on Equation (1) mentioned in Zeng et al [19] and the statistical results are shown in Figure 3.…”

Design and evaluation of pneumatic impact‐twisting combined walnut fixed posture shell‐breaking mechanism

“…Both domestic and international scholars have conducted extensive research on walnut shell‐breaking methods (Ding et al, 2017; Wang et al, 2022; Zhang et al, 2018). Most research outcomes are concentrated on traditional single‐shell methods or their improvements, overlooking the study of combining various shelling methods (Barakaev et al, 2021; Cao et al, 2017).…”

Physico-chemical characterization of walnut shell biochar from uncontrolled pyrolysis in a garden oven and surface modification by ex-situ chemical magnetization

“…Due to high domestic processing costs, even walnuts cultivated in developed countries such as France are exported to Moldova for shelling and then reimported to minimize the walnut processing costs (CBI 2019). Thus, sustainable valorizing of walnut shells (WS) can help, to an extent, in offsetting the cost of shelling which itself is a complex and resource-intensive process (Wang et al 2022).…”