Blood alcohol test appts.

摘要

The appts. to test the alcohol content in blood has a dose chamber (14) with a fixed holding vol. capacity. An electronic or electro-mechanical pressure sensor (42) generates an electrical output signal at least when an upper threshold value is breached, to operate a change valve (28) connecting the dose chamber (14) to the measurement chamber (29) with its equalising flow path (38) to the ambient atmosphere to be opened in the function setting.An airstream injector (32) takes part of the expelled air from the filling of the dose chamber (14) as a drive stream. The function control valve (28) gives a selected link between the dose chamber (14) and the measurement chamber (29) or between the measurement chamber (29) and the injection chamber (31) of the air injector (32) to flush the measurement chamber (29) for a given time span, while the equalising path (38) is held open for the air expelled from the measurement chamber (29).