Breath testing system

Abstract

Abstract AN ALCOHOLIC BREATH ANALYZER WHICH EFFECTIVELY RESPONDS ONLY TO ALCOHOL CONTENT OF A SUBJECT''S BREATH. IT IS IMMUNE TO OTHER BREATH CONSISTUENTS, AS WELL AS TO TEMPERATURE VARIATIONS, THAT COULD OTHERWISE HAVE AN ADVERSE EFFECT AND LAD TO FALSE TEST RESULTS. THIS IMMUNITY IS ACHIEVED BY ALTERNATELY SUPPLYING TO THE INPUT OF AN ALCOHOL DETECTOR TWO BREATH SAMPLES IDENTICAL TO EACH OTHER EXCEPT THAT ALCOHOL, IF ANY, HAS BEEN REMOVED FROM ONE OF THEM. IN THIS WAY, THE SAMPLES REACHING THE DETECTOR WILL BE THE SAME WHEN THE SUBJECT''S BREATG IS ALCOHOL-FREE AND ANY REACTION TO THOSE SAMPLES WILL BE CONSTANT. AS A CONSEQUENCE, THE INSTANTANEOUS AMPLITUDE OF THE OUTPUT SIGNAL FROM THE DECTOR REMAINS SUBSTANTIALLY FIXED (NAMELY THE SIGNAL WILL HAVE A CONTANT AMPLITUDE D.C. COMPONENT) EVEN THROUGH THE DETECTOR MAY RESPOND TO AND BE AFFECTED BY THE NON-ALCOHOL CONSTITUENTS AND BY TEMPERATURE CHANGES. ON THE OTHER HAND, WHEN BREATH ALCOHOL IS PRESENT, THE CHOPPING PROCESS EFFECTS DELIVERY OF THAT ALCOHOL TO THE DETECTOR IN TIME-SPACED PLUSES OR BURSTS AND THIS CAUSES THE DECTOR''S OUTPUT SIGNAL TO VARYING IN ACCORDANCE WITH A SQUARE WAVE FUNCTION AND IN STEP OR SYNCHRONISM WITH THE SWITCHING BETWEEN SAMPLES AT THE DETECTOR''S INPUT. THE PEAK-TO-PEAK AMPLITUDE OF THE RESULTING A.C. COMPONENT WILL ACCURATELY REPRESENT THE BREATH ALCOHOL CONCENTRATION.

Inventors

• 👤 H Venema

Bibliographic Details