| 摘要 |
<p>A mask device with a blower has an alarm sensor (15) for outputting a sig nal by detecting without contact a position (d2) of an exhaust valve (7) aft er its movement that corresponds to a reduction in the inner pressure of a s urface body to a level lower than an external air pressure occurring in air intake. An alarm device is activated by the signal from the alarm sensor (15 ).</p> |
