Abstract:
In order to promote the calibration accuracy of pressure drop standards, a calibration method via adjusting volume flow was proposed. The proposed calibration method was compared with the existing CFO (Critical Flow Orifice) method in terms of repeatability and stability. The proposed calibration method was used in the collaborative studies of pressure drop standards organized by CORESTA. The results showed that: 1) Comparing with CFO method, the volume flow-based method decreased the standard deviation, the variance coefficient of calibration results and the extreme error of calibration results in a period of five months by more than 50%. 2) The relative extreme error between the mean values of calibration results of the laboratory in ZTRI (Zhengzhou Tobacco Research Institute, Zhengzhou, China) and three foreign laboratories was less than 0.40%; the coefficient of variation of calibration results in the four laboratories was less than 0.10%. This method can be used to improve the accuracy of measurement results of cigarette draw resistance and filter pressure drop.