Enabling a low-resistance high-accuracy flowmeter for the diagnosis of chronic obstructive pulmonary disease

•A ball blocking differential pressure flowmeter replaced the traditional restriction block of the fixed orifice to obtain lower flow resistance for the diagnosis of COPD was proposed.•Special pressure tapping was selected to gain a biggest possible measured differential pressure.•Superiority of sensitivity and flow resistance was reflected in comparison to the single-hole and multi-hole flowmeters. We aimed to develop a low-resistance and high-accuracy way to measure expiratory volume for the accurate classification of chronic obstructive pulmonary disease (COPD). In this paper, using computer-aided design (CAD), a ball-blocking differential pressure flowmeter (BBDPF) has been developed and then fabricated using 3D printing. Ball blocking is used for the designed flowmeter to replace the traditional restriction of the differential pressure flowmeter for lower flow resistance, and special pressure tapping is selected for high accuracy. The BBDPF is theoretically and experimentally characterized, using ANSYS fluent® software with turbulent model simulations. Then, we validate the flowmeter, using pulmonary waveforms generator with flow resistance tests and the standard spirometry tests (ATS24/26). The results demonstrate that in comparison with other type differential pressure flowmeters, the structure of BBDPF effectively reduces flow resistance (144.41 Pa/L/s at 14 L/s) with accuracy(±3% of reading or ± 0.050 L,whichever is greater) in the range of 0 − 17L/s with a resolution of 0.01 L/s. This is confirmed by the application in expiratory volume measurement of the reported work functions well.