Fleisch Pneumotachometer is one of the most common types of airflow transducers. It consists of a straight short-tube with a fixed screen obstruction in the middle that produces a slight pressure drop as the air is passed through the tube. The pressure drop created across the screen is measured by a differential pressure transducer.
The signal produced by the pressure transducer is proportional to the air velocity. The tube is normally shaped in a cone to generate a laminar airflow pattern. A small heater heats the screen so water vapor does not condense on it over time and produce an artificially high pressure drop.
Fleisch pneumotachometers are employed in monitoring volume, flow, and breathing rates of patients on mechanical ventilators.
Related: Functions & Types of Pneumotachometers for Biomedical Measurements
