Spirometer apparatus comprising main inhale-exhale tube having first end, main interior, and second open end, a plurality of smaller tubes intersecting said main-inhale exhale tube at first and second respective locations and having a plurality of smaller interiors respectively, the first location being closer to the first end than is the second location, wherein each of the smaller interiors are in fluid communication with the main interior solely via at least one aperture formed in each of the intersecting tubes at locations facing said second end, the intersecting tubes having first and second external cross-sections, the main tube having first and second internal cross-sections, wherein said first external cross-section is smaller than said first internal cross-section, said second external cross-section is smaller than said second internal cross-section, and wherein said second external cross-section is smaller than said first external cross-section, and a differential pressure sensor sensing the pressure drop.肺活量計装置が、第1の端部、主内部、及び第2の端部を有する主要な呼吸管と、第1及び第2の各位置で前記主要な呼吸管を横断し複数の小さな開口をそれぞれ有する複数の小さな管とを具えており、第1の位置は第2の位置よりも第1の端部に近く、小さな内部管のそれぞれは、前記第2の端部に面する位置でそれぞれの横断管に形成された少なくとも1の開口のみを介して主要な内部と液通し、横断管は第1及び第2の外側断面を有し、主要管は第1及び第2の内側断面を有し、前記第1の外側断面は前記第1の内側断面よりも小さく、前記第2の外側断面は前記第2の内側断面よりも小さく、前記第2の外側断面は前記第1の外側断面よりも小さく、差圧センサが圧力低下を検出する。【選択図】図5B
