Research on the performance evaluation method of rotary reduction machine for coal sampling

CHU Kuiming; WANG Jian; SHEN Yushuang; WU Bihai

doi:10.3969/j.issn.1007-7677.2023.06.011

Abstract：The performance evaluation of a rotary divider for coal sampling ensures the precision of sampling through precision verification and bias testing,and confirms that the retained sample after division can represent the charac-teristics of the sample before division.This article mainly discussed a performance evaluation method for a rotary divi-der for coal sampling,evaluating whether the rotary divider meets the requirements from the technical parameters such as cutting speed,number of cut subsamples,opening size,uniformity of sample quality after division,precision of division,and bias of the division system.The uniformity of sample quality after division was evaluated by calculating the coefficient of variation of the mass of each sample after division.The accuracy and bias of the reduction were veri-fied by checking whether the single,two,and four samples retained after reduction met the requirements of the na-tional standard.The bias was calculated by calculating the weighted average of the retained and discarded samples as a reference value and comparing it with the retained samples.According to GB/T 19494.3,the bias test of the me-chanical rotary reduction machine was conducted from the aspects of outlier testing,logarithmic testing,difference independence testing,standard deviation calculation and t-test.The experimental results show that the technical pa-rameters,sample quality uniformity,and accuracy of the mechanical rotary reduction machine after reduction could meet the requirements of the national standard.The bias is acceptable as a non-biased system when the B value was set to 0.15.