Abstract: A peak respiratory flow monitor utilizes an enclosure having a series of openings through the wall thereof, a provision for covering a desired number of these openings, and a provision for generating a signal when the air flow through the enclosure reaches a threshold. In a preferred embodiment the enclosure includes an elongated tubular member, and the threshold indicator is a reed placed in a chamber that has an adjustable valve for calibrating the flow past the reed. Furthermore, the chamber causes a displacement of flow from along the longitudinal axis of the tubular member.

Abstract: A device for calibrating a Spirometer includes a hand driven syringe having magnetic elements displaced along the shaft of the syringe piston at intervals corresponding to designated volumes. A Hall effect transducer senses the passage of the magnetic when the syringe piston is actuated and transmitts pulses to a timer so that average rate of flow delivered by the syringe can be derived.