Compact Breathing Sensor with Humidified Air Delivery

Piezoelectric actuators as fans for air delivery are very attractive due to their ultra-lightweight, small power consumption, and low noise. Therefore, recent studies were taken on piezoelectric actuators as a potential alternative to air compressor/blower for biomedical devices. In this application, such as breathing devices, the airflow to the patient's mouth needs to be humidified. This study attempts to develop an integrated piezoelectric actuator-based breathing device to generate humidified airflow. The integrated system comprises a piezo fan for generating actuation and airflow. The moisture from the surface of the actuator blade is also transported to combine with airflow for humidified air delivery. The micro-structured actuator blade is acting as a moisture reservoir, and water is continuously supplied through the micro-tube to the surface of the blade. The continuous actuation of the blade establishes constant water evaporation from the surface of the actuator blade. The evaporated water vapor from the blade surface can easily be combined with delivered airflow by the actuator blade. The optimum humidified airflow can be obtained by an appropriate design (size and shape of the fan, moisture carrier/reservoir) of integrated piezoelectric actuator devices. This work demonstrates the fabrication process and the device characterization by measuring the delivered airflow and optimum resonance frequencies. This novel technique is very object-oriented for miniaturized breathing devices and very promising for biomedical applications.