摘要:
The present invention relates to a method and apparatus for measuring breath alcohol concentration of a user. A flow of an expired breath sample is passed through a fuel cell sensor giving an output signal proportional to the amount of alcohol present in the breath sample. By measuring the pressure, the volume of the breath sample may be calculated by integrating the pressure over the time of expiration of the breath sample, whereas the breath alcohol concentration is calculated based on the fuel cell output signal. Both the sample volume and the breath alcohol concentration values are continually updated by integrating the measured instantaneous pressure and the fuel cell output signal over time, irrespective of the breath sample volume. When the user stops blowing,volume compensation is performed to obtain a compensated fuel cell output signal using a stored calibration volume. Hence, an improved method for accurately measuring the breath alcohol concentration of a test person is achieved, capable of handling varied expired volumes of breath,which obviates the need for a sampling mechanism.
摘要:
An apparatus for heating a breath alcohol testing device having a fuel cell sensor (2) prior to performing a measurement of breath alcohol concentration, characterised in that the apparatus comprises means (1) for receiving a flow of expired air from a user and leading it to the fuel cell sensor, a separate conduit (3)in fluid communication with the receiving means and the fuel cell sensor and configured to receive the flow of expired air, wherein the conduit comprises means (4) for reducing the humidity of the expired air before the dehumidified expired air is further directed to the fuel cell sensor in order to heat the fuel cell sensor.
摘要:
A calibration device (1) for a breath alcohol testing device, comprising a pump (2) configured to provide a controlled flow of air at a predetermined rate, a chamber (3) in fluid communication with the pump and adapted to receive the flow of air from the pump, and an outlet opening (4) in fluid communication with the chamber adapted to allow the flow of air to exit the chamber, and heating means (5) configured to heat the chamber and/or outlet opening to a predetermined temperature and to maintain the predetermined temperature during operation of the pump, wherein the calibration device is configured to be releasably connected to or brought in fluid communication with a breath alcohol testing device such that the flow of air exiting the outlet opening is passed into the breath alcohol testing device. The calibration device is adapted to receive a sealed cartridge (7) containing a predetermined concentration of alcohol in the chamber and further com¬ prises a lid for opening/closing the chamber and co-operating with means for piercing the cartridge such that the flow of air provided by the pump to the chamber will pass through the cartridge, thereby providing a sample containing the predetermined concentration of alcohol to the breath alcohol testing device.
摘要:
The present invention relates to a method and apparatus for measuring breath alcohol concentration of a user. A flow of an expired breath sample is passed through a fuel cell sensor giving an output signal proportional to the amount of alcohol present in the breath sample. By measuring the flow rate, the volume of the breath sample may be calculated, whereas the breath alcohol concentration is calculated based on the fuel cell output signal. Both the sample volume and the breath alcohol concentration values are continually updated by integrating the measured instantaneous flow rate and the fuel cell output signal over time. If the user stops blowing,flow compensation is performed to obtain a compensated fuel cell output signal using a stored calibration volume. Hence, an improved method for accurately measuring the breath alcohol concentration of a test person is achieved, capable of handling varied expired volumes of breath,which obviates the need for a sampling mechanism.