| 摘要 |
Herein disclosed is a peak expiratory flow rate measuring apparatus (PFM) having at least one measurement channel and at least one bypass flow channel comprising at least one entrance, at least one exit, at least an inner wall and an outer wall, and wherein at least a portion of said at least one bypass flow channel has a variable cross-sectional area. Further disclosed is a PFM having at least one measurement channel comprising at least one first flow entrance, at least one bypass flow channel comprising at least one second flow entrance, and at least one guide wall, having an axially forward portion adjacent to said second flow entrance and an axially aft portion adjacent to said first flow entrance. Still further disclosed is a PFM comprising at least one measurement channel having at least one first flow entrance, at least one bypass flow channel having at least one second flow entrance, wherein at least a portion of said at least one bypass flow channel comprises a variable cross-sectional area, and at least one guide wall, comprising an axially forward portion adjacent to said second flow entrance and an axially aft portion adjacent to said first flow entrance.
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