Abstract
Chest drainage units are medical tools for pneumothorax. They drain the leak air from the patient's lungs. However, there's no device to measure amount of the leak without connecting with the units directly. When the air passes through the water seal in the units, the bubble appears periodically and its frequency depends on the air flow rate. We developed a new type of the flow meter for the drainage unit by sensing electrical capacitance of the water seal, which correlates to the instantaneous volume of the bubble in the water seal, and quantify the flow rate based on its signal. At the lower flow rate such as 0.3L/min the error is 6%.
