| 摘要 |
A peak flow meter is provided comprising an elongated body having a longitudinal direction and a predetermined cross sectional shape and a growing area. The body has an open entering end and an open exit end. The body is circumferencially continuous substantially from end to end. A piston and an indicator are mounted in said body for movement longitudinally thereof upon exhalation into the open entering end. The indicator is pushed along said body for movement by the piston longitudinally of said body. The indicator is of low mass so as not to overshoot, and is returned to rest by shaking a weight against it. A logarithmic scale is provided along said body against which the position of said indicator can be read.
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