Spirometer Diagram - How a Water-Sealed Spirometer Measures Lung Capacity #268277 (License: Personal Use)

This diagram illustrates a traditional water-sealed spirometer, where exhaled air displaces water in the oxygen chamber, causing the floating drum to rise and rotate the recording drum via a pulley system. A counterbalancing weight maintains tension on the drum assembly, ensuring accurate tracing of airflow volume over time on the rotating paper chart. The mouthpiece connects directly to the subject, enabling real-time measurement of inhalation and exhalation volumes.

Used in medical education, respiratory physiology textbooks, and clinical training materials to explain foundational spirometry principles; targets students, clinicians, and researchers seeking to understand historical or mechanical lung function testing methods.