G - Physics – 01 – N
Patent
G - Physics
01
N
73/78, 73/97
G01N 25/20 (2006.01) G01N 33/48 (2006.01) G01N 33/497 (2006.01)
Patent
CA 1139586
ABSTRACT There is disclosed a method of separating exhaled gas into two portions, A body in a first duct is heated to a starting temperature. The exhaled gas is passed through the first duct and around the body to cool the body. When the temperature of the body has fallen by a predetermined amount, further exhaled gas is caused to pass through a second duct. The apparatus for carrying out the method includes a heater, a temperature probe and a controller for controlling the actuation of the heater and of a valve for switching the flow to the second duct. The invention is applicable to the separation of exhaled air into two portions, the first of which can be dis- counted and the second of which can have its alcohol concentration determined. In the second portion the concentration of alcohol should correspond to the concentration of alcohol in the blood. The method according to the present invention utilises the new knowledge that the alcohol concentration in exhaled air varies continuously and is found both in the portion of respiratory air from the lungs and in the air from the other respiratory organs. Even the respiratory air flowing when exhalation commences can be utilized to determine the testing moment, i.e. the time when the alcohol concentration is measured. The further exhaled air, hence the sample for the alcohol measuring sensor is introduced into a measuring chamber when the body is cooled by a temperature difference .DELTA. T. Cooling of the body depends on the total volume of air which flows past the body, and on the period of time in which it flows by. The re- quirement for the moment at which the sample is taken (i.e. the moment when the further exhaled air commences flowing through the second duct) is therefore met either by a large volume exhaled over a short period or by a small volume ex- haled over a fairly long period. In both cases, reliable measured values for alcohol are obtained. The individual differences between the individual test subjects do not affect the result of measurement in this connection.
346132
Heim Ulrich
Kempin Hans-Friedhelm
Dragerwerk Aktiengesellschaft
Fetherstonhaugh & Co.
LandOfFree
Method and apparatus for separating exhaled gas into two... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for separating exhaled gas into two..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for separating exhaled gas into two... will most certainly appreciate the feedback.
Profile ID: LFCA-PAI-O-456232