| 摘要 |
<p>A spirometer having an inflatable bellows, is provided with a movable member which runs along a track. The configuration of the track is adjustable, and by such adjustment the configuration is set locally to give a variable resistance to movement of the member and, consequently, to inflation of the bellows. Callibration is achieved in a simple manner by adjusting the track at the position of engagement with the movable member as the bellows is inflated progressively with measured amounts of air. Adjustments made correctly are not upset by adjustments made later in the callibration operation. In contrast, with the known procedure of callibration by moving the bellows, or by loading the gussets of the bellows with wires or strips, during such progressive inflation, adjustments made do not affect adjustments made at an earlier stage of the inflation.</p> |
