为了提高散体物料孔隙率检测精度及可靠性,基于理想气体状态方程,按照气体置换法,研制了一种定容型散体物料孔隙率的快速测定装置,开发了自动检测控制系统。在设定的0.1~0.4 MPa测量范围内,采用可精确测得其体积且形态各异的标准不锈钢球体、塑料四棱柱体、鹅卵石以及细石子的试验结果发现,系统的充气压力越高,测量误差相对越小且重复性越好。采用标准不锈钢球体与圆柱体,在孔隙率分别为16.02%、25.14%、35.57%、49.05%、58.42%、67.79%、76.57%、85.36%、94.14%的标准条件下,给出了补偿系数的计算式。在样品填充率分别为25%、50%、75%、100%,充气上限压力为0.4 MPa的试验条件下,检测湿基含水率为13.5%的稻谷的试验结果显示,测量误差极差为0.3%,证实了测量结果的可靠性。
To improve detection precision and reliability of the porosimeter for particle materials,a constant volume porosimeter and an automatic control system were developed based on the ideal gas state equation and gas displacement method.In 0.1 ~ 0.4 MPa,the results showed that the higher the inflation pressure,the better the repeatability and precision of porosimeter when stainless steel balls,prisms,pebbles and fine stones were used in the test.The equation of error compensation was proposed through the calibration experiment using standard stainless steel balls and cylinders in the standard condition.The porosity of the samples were 16.02%,25.14%,35.57%,49.05%,58.42%,67.79%,76.57%,85.36%,94.14% respectively.In the inflation pressure limit of 0.4 MPa,with 13.5% wet basis of paddy porosity,the test results showed that the range of porosity was 0.3%,when filling rates of sample were 25%,50%,75%,100% respectively.The reliability of measurement was proved by the results.