WO1992022813A1

WO1992022813A1 - Breath alcohol analysis apparatus

Info

Publication number: WO1992022813A1
Application number: PCT/AU1992/000297
Authority: WO
Inventors: Laddy Nadilo
Original assignee: Alcohol Measuring Equipment Pty. Limited
Priority date: 1991-06-19
Filing date: 1992-06-18
Publication date: 1992-12-23

Abstract

A breath alcohol analysis apparatus (10) has a sample chamber (13) for collecting a breath sample, a breath alcohol detector (12) and electronic means (15) for processing data from the sample chamber (13) and the breath alcohol detector (12). The apparatus (10) also includes means (11) for heating the sample chamber (13) and/or the breath alcohol detector (12). The apparatus (10) may be used to affect operation of a vehicle if alcohol in the breath sample exceeds a predetermined limit.

Description

BREATH ALCOHOL ANALYSIS APPARATUS

TECHNICAL FIELD

This invention relates to breath analysis technology. More particularly, although not exclusively, this invention concerns a breath alcohol analysis apparatus for detecting a level of concentration of alcohol in blood.

BACKGROUND ART

It is commonly known that random breath testing of drivers is conducted under the law in many countries. Hand-held breath analysers are widely used by police forces throughout the world for initial screening purposes.

Further, self-testing breath analysers are available for personal use of those drivers who wish to ensure that their blood alcohol level does not exceed the legal limit. Such known breath analysers may be either hand¬ held or vehicle-mounted. These analysers may be linked to the vehicle so as to prevent starting of the vehicle or to warn the driver if the driver's breath alcohol reading exceeds a certain limit.

There are also available wall-mounted breath analysers. These are especially useful for installation in public places (such as discotheques, restaurants, etc.) and factories where control of workers in this direction is desirable.

Known breath analysers employ micro-computer technology in conjunction with electrochemical fuel cells incorporated into breath alcohol sampling systems, designed to achieve accurate, repeatable readings which are specific to alcohol, even in the presence of carbon monoxide from smokers, acetone from diabetics or any other constituent which may be present in the breath from time to time.

While the presence of the fuel cell in the breath alcohol sampling system is intended to produce such accurate readings, both breath alcohol sampling systems in general and fuel cells in particular have been found to suffer serious disadvantages.

The main problem associated with fuel cells is the long recovery time after a breath alcohol sample has been taken. Depending on the alcohol concentration level in the previous sample, this may be as long as 3 to 5 minutes. This is not acceptable in situations such as those where breath analysers are used in road test booths by police, public places or factories, etc., since the estimated between the tests is approximately 30 seconds.

Another problem of the prior art is associated with the breath alcohol sampling system wherein, after every successive breath alcohol sample taken, moisture builds up in the sample chamber with residual alcohol content left in the moisture. The presence of the residual alcohol content may produce incorrect readings. For example, when successive breath alcohol samples are taken, the alcohol content of each sample is combined with the residual alcohol content built up in the chamber causing false, higher readings. This problem may be especially serious in the situations such as where a vehicle is inhibited from starting if the breath alcohol reading is more than a predetermined amount or where it needs to be established whether legal limits of the alcohol concentration in blood have been observed.

DISCLOSURE OF THE INVENTION

It has now been found that the fuel cell recovery time can be reduced to an acceptable level by increasing the operating temperature of the fuel cell to a suitable level, such as 40 to 50 degrees Celsius.

It has also been found that the problem of residual alcohol can be overcome by heating the sample chamber so as to convert the moisture into its vapour phase.

Accordingly, the present invention provides a breath alcohol analysis apparatus having a sample chamber for collecting a breath sample, a breath alcohol detector and electronic means for processing data from the sample chamber and the breath alcohol detector, characterised in that the apparatus includes means for heating the sample chamber and/or the breath alcohol detector.

It is preferred that the breath alcohol analysis apparatus of the invention includes means such as a pump for injecting a portion of the breath sample into the detector.

The means for heating the sample chamber and/or the breath alcohol detector are intended to overcome or substantially alleviate either or both of the two major problems disclosed above.

In some instances it may be desirable or sufficient to alleviate one problem only. Therefore, either the sample chamber only or the breath alcohol analysis detector only may be heated. However, it is preferred that there are provided means for heating both the sample chamber and the breath alcohol detector, so as to obtain the maximum benefit in the performance of the breath alcohol analysis apparatus. It is especially preferred that both the sample chamber and the breath alcohol detector are heated simultaneously by single heating means although it is contemplated that some other heating arrangement may be used.

In a preferred embodiment of the present invention, the means for heating the sample chamber and/or the breath alcohol detector comprise a heater block, a heating transistor and a temperature sensor adapted to detect the temperature of the heater block.

The heater block is preferably a plate onto which the heating transistor and the temperature sensor may be mounted.

It is preferred that the heater block be made of a material which is stable under the conditions of use.

It is especially preferred that the heater block is made of aluminium.

The heater block may be heated to about 40 to 50 degrees Celsius or to some other appropriate temperature by the heating transistor. The temperature of the heater block may be controlled by the temperature sensor acting in cooperation with suitable electronic means, the electronic means being adapted to process data from the temperature sensor so as to maintain the temperature at the required level at all times.

Preferably, the breath alcohol detector is an electrochemical fuel cell, mounted onto or recessed into the heater block in such a way that in use an even heat distribution is provided across the cell.

It is especially preferred that the breath alcohol detector is recessed into the heater block. The sample chamber preferably includes an inlet port, an exhaust port, a check valve adapted to prevent the escape of a breath sample from the sample chamber through the inlet port and a liquid detector adapted to prevent saturation of the breath alcohol detector. The sample chamber may be mounted onto the heater block in such a way that an even heat distribution is provided across the sample chamber and extends to the inlet and exhaust ports. The inlet port may be adapted to accommodate a standard drinking straw through which a subject may inject a breath sample.

Preferably, an exhaust tube is attached to the exhaust port so as to allow a volume of the breath sample, in excess of that required for analysis, to be exhausted therethrough.

The check valve may be provided in order to prevent a subject from inhaling vapours present in the sample chamber. The check valve is preferably a gasket made of material such as teflon, neoprene or the like.

As is further described in connection with the Drawings, below, it is preferred that the gasket be mounted onto the exhaust orifice of the inlet port. It is especially preferred that a movable flap or tongue be provided to facilitate the operation of the check valve.

The liquid detector may be provided to prevent saturation of the breath alcohol detector in situations where a breath sample may contain excessive concentration of liquid. It is preferred that the detector is connected to the exhaust orifice of the inlet port. It is further preferred that the detector is coupled to an electronic circuit. These features are described in connection with the Drawings.

When the subject injects a breath sample into the sample chamber, the liquid detector may measure the concentration of liquid in the sample and transmit the resulting information to the electronic means for processing. If the concentration of liquid in the sample exceeds an acceptable level, the electronic means may disallow activation of the pump means. The breath sample may then be exhausted via the exhaust tube.

The sample chamber may be designed so as to allow breath sample pressure or volume to be measured in order to ensure that a required volume of air has been expired.

In a preferred embodiment of the present invention described in connection with the Drawings, the breath sample pressure is detected by a pressure sensor; data from the pressure sensor is processed by electronic means, to provide a visual indication, for example, if insufficient breath sample has entered the sample chamber. When a sufficient volume of the breath sample passes through the inlet and exhaust ports of the sample chamber, the pump means is activated so as to inject a required volume of the breath sample into the fuel cell for breath alcohol analysis. A signal from the fuel cell is then transmitted to the electronic means for processing, and a breath alcohol reading is displayed in an appropriate manner on a visual display.

Preferably, the breath alcohol reading is displayed on an alpha-numeric static electronic readout or on a progressive electronic readout.

The pump means and electronic means may also be mounted onto the heater block.

In another embodiment, the apparatus of the present invention may be connected to a vehicle so as to be capable of affecting the operation of the vehicle, for example, by inhibiting starting of the vehicle, immobilising the vehicle or warning the driver if the driver's breath alcohol reading exceeds the legal limit.

In this embodiment, the apparatus may be hand-held (and capable of connection to the vehicle) or vehicle-mounted. Signalling means are provided, adapted to send a signal to the vehicle to affect the operation of the vehicle if alcohol in the breath sample exceeds a predetermined limit. When vehicle-mounted, the apparatus may be connected to the vehicle's battery in a known manner.

When hand-held, the apparatus will include an inbuilt power source, such as a battery pack. The hand-held breath alcohol analysis apparatus may also be adapted to be connected to the vehicle's battery when required.

It is greatly preferred that the breath alcohol analysis apparatus is hand-held and not wired in to the vehicle's electrical system, for a number of reasons. Such an apparatus is easily portable; it may be used both in the vehicle and out of the vehicle, for instance as a personal testing device where there is no need to interface with a vehicle at all. The apparatus may be re-calibrated as required without having to deliver the vehicle as well.

In cold climate conditions (below approximately 10 degrees Celsius), the apparatus in the hand-held form may be required to be connected to the vehicle's battery in order to initiate the operation of the heating transistor. The device may display a message to this effect if the temperature sensor is appropriately affected.

In these preferred embodiments, the signalling means are preferably remote and may include an infra-red or radio frequency transmitter adapted to send a signal. depending on the nature of the test results, to a receiver suitably mounted on or in the vehicle. The receiver may be interfaced with the vehicle's electrical and/or electronic control systems, for example, so as to prevent starting of the vehicle's engine if the test results exceed a certain level. Alternately or in addition, the signal may generate a message to the driver regarding the test results.

For example, if alcohol in the breath sample exceeds a predetermined limit and the vehicle has not been started, the operation of the vehicle may be affected by either inhibiting the starting of the starter motor (until alcohol decreases to a permissible level) or providing a warning to the driver, or both.

If the vehicle is already in motion and the purpose of the test is to re-check the driver's breath alcohol level, the signal may generate a warning to the driver. If the breath alcohol level exceeds the predetermined limit, the warning may be followed by an alarm such as flashing of the vehicle lights and/or operation of the horn, optionally followed by shutting down of the engine within a short time frame if the driver has not turned off the engine by that stage.

The transmitted signal may be digitally coded. The receiving unit may have the facility of storing data which then may be downloaded to a printer or computer. Preferably, any message referring to the breath alcohol reading is displayed on an alpha-numeric static electronic readout or on a progressive electronic readout.

Where the apparatus of the present invention is wall mounted, it may be desirable to provide a coin-freed mechanism including a slot adapted to receive coins to actuate the breath analysis procedure. It is contemplated that the slot may also be adapted to receive a card with an electromagnetic tape having a function of an identification card, for example a so-called "smart card". In such situations when an identification card is used, an interface may connect the breath alcohol analysis apparatus of the present invention to an outside computer so as to allow data on a particular individual to be logged and stored.

If desired, the interface may be connected to a computer of a financial institution so as to allow automatic debiting of an identified account of a fee for use of the apparatus. Alternately, a push button system, similar to that used in building security access systems, may be used instead of the identification card.

It may be preferred to include a real-time clock in the apparatus of the present invention so that a signal can warn of the need for recalibration, which may need to be carried out every 30 days. BRIEF DESCRIPTION OF THE DRAWINGS

By way if example only, some preferred embodiments of the present invention will now be described with reference to the accompanying drawings, wherein:

Fig. 1 is a schematic elevational view of one preferred embodiment of the apparatus of the present invention; and

Fig. 2 is a schematic side view of the apparatus of Fig. 1 viewed in the direction of arrow A in Fig. 1.

In the drawings, breath alcohol analysis apparatus 10 is provided with heater block 11 onto which breath alcohol detector 12, sample chamber 13, pump means 14 and electronic means 15 are mounted. Also mounted onto heater block 11 are a heating transistor, a temperature sensor and a pressure sensor (not shown) .

Heater block 11 is a plate made of aluminium, which is stable under the conditions of use. Heater block 11 is approximately 70 mm high, 40 mm wide and 6 mm thick. Heater block 11 is heated to about 50 degrees Celsius by the heating transistor. The temperature is controlled by the temperature sensor, which measures the temperature of heater block 11 and transmits the resulting information to electronic means 15. Electronic means 15, in turn, control the amount of power to be applied to the heating transistor. Breath alcohol detector 12 is provided to detect and measure the concentration of alcohol in the breath sample taken and comprises an electrochemical fuel cell, recessed approximately 2.5 mm into the body of heater block 11 so as to obtain an even heat distribution across its surface. The fuel cell is available commercially from Lion Laboratories Ltd in England.

Application of sufficient heat by heater block 11 to breath alcohol detector 12 reduces the recovery time of detector 12 to an acceptable level, namely 30 seconds or less.

Sample chamber 13 serves to receive a breath sample and is provided with inlet port 13A, exhaust port 13B, check valve 18 and liquid detector 19. Sample chamber 13 is mounted onto heater block 11 in such a way as to obtain an even heat distribution across the chamber.

Inlet port 13A is adapted to receive standard drinking straw or tube 17 through which a subject injects the breath sample. Exhaust tube 16 is attached to exhaust port 13B so as to allow a volume of the breath sample, in excess of that required for analysis, to be exhausted therethrough.

One way check valve 18 is provided to prevent a subject from inhaling vapours present in sample chamber 13. Check valve 18 is a gasket made of teflon. The gasket is mounted onto the exhaust orifice of inlet port 13A and a movable flap or tongue is provided so as to cover the exhaust orifice. When the subject injects a breath sample into sample chamber 13, the flap moves in a direction allowing the breath sample to pass through the orifice. If the subject tries, accidentally or intentionally, to inhale vapours present in sample chamber 13, the flap will seal the orifice preventing the subject from doing so.

Liquid detector 19 is provided to prevent saturation of alcohol breath detector 12 in situations where a breath sample contains excessive concentration of liquid. Liquid detector 19 comprises two wires (one of which is shown in Fig. 1) inserted into the exhaust orifice of inlet port 13A and coupled to an electronic circuit (not shown) . When the subject injects a breath sample into sample chamber 13, liquid detector 19 measures the concentration of liquid in the sample and transmits the resulting information, via the electronic circuit, to electronic means 15 for processing. If the concentration of liquid in the sample exceeds an acceptable level, electronic means 15 will prevent activation of pump means 14. The breath sample will then be exhausted via exhaust tube 16.

Application of heat by heater block 11 to sample chamber 13 converts any moisture present in sample chamber 13 into the vapour phase. This facilitates purging of sample chamber 13 with every successive breath sample taken and, therefore, ensures that contamination of sample chamber 13 by residual alcohol is reduced to an acceptable level.

As the subject injects a breath sample, heated sample chamber 13 becomes purged of contamination. At the same time, the inlet pressure is measured by the pressure sensor in order to determine the volume of air expired by the subject. When approximately 1 to 1.5 litres of air have passed through inlet port 13A and exhaust port 13B, pump means 14 are activated, injecting approximately 1 cubic centimetre of the breath sample into breath alcohol detector 12 for analysis. The remaining volume of the breath sample (in excess of that required for analysis) is exhausted through exhaust tube 16. Breath alcohol detector 12 outputs a voltage proportional to the concentration of breath alcohol and this is then transmitted to electronic means 15 for processing. As a result of the heating of detector 12, it quickly recovers and breath alcohol analysis apparatus 10 is ready to receive the next breath sample approximately 30 seconds later.

When the apparatus of the invention is used as a wall-mounted or hand-held breath test unit, processing of the response to the breath alcohol concentration will result in the generation of a visual display in known manner. However, when the apparatus is adapted to affect the operation of a vehicle, the processing of the response to the breath alcohol concentration will result in the generation of a signal by radio waves to a receiver in the vehicle (not shown) . The transmission of the signal can work in known manner, similar to the opening of a garage door by remote control, for example. The receiver may be configured to accept a signal from a specifically coded analysis apparatus, so that breath alcohol analysis apparatus intended for use in other vehicles will not be interchangeable without adjusting the code.

The receiver in the vehicle is interfaced with the vehicle's electrical and/or electronic control system, so that the starting of the vehicle is inhibited until a "pass" test result is transmitted to the receiver.

For use in emergencies, an override facility may be inserted in the system, so that the vehicle may be driven by a person having more than the prescribed breath alcohol concentration if necessary.

The receiver may be configured to store data for later downloading, so as to record the date and time of each test, the concentration of breath alcohol (above or below a certain value) and whether the vehicle was started and driven without a test being conducted. It will be appreciated that the breath alcohol analysis apparatus of the present invention is a simple but effective advance over the prior art. The apparatus is suitable for incorporation in a wall-mounted or hand-held test unit or as part of a vehicle breath monitor system. It will be also appreciated that preferred embodiments of the present invention disclosed herein are given by way of example only and are not intended to be limiting on the scope of the present invention.

Claims

1. A breath alcohol analysis apparatus having a sample chamber for collecting a breath sample, a breath alcohol detector and electronic means for processing data from the sample chamber and the breath alcohol detector, characterised in that the apparatus includes means for heating the sample chamber and/or the breath alcohol detecto .

2. Apparatus as claimed in claim 1, which further includes means for injecting a portion of the breath sample into the detector.

3. Apparatus as claimed in claim 1, wherein the heating means comprise a heater block adapted to be heated to a desired temperature by a heating transistor together with a temperature sensor adapted to detect the temperature of the heater block.

4. Apparatus as claimed in claim 3, wherein the detector is an electrochemical fuel cell mounted onto or recessed into the heater block so that in use even heat distribution is provided across the cell.

5. Apparatus as claimed in claim 1, wherein the heating means is adapted to heat both the sample chamber and the detector simultaneously.

6. Apparatus as claimed in claim 1, wherein the heating means is adapted to heat the sample chamber and/or the detector to a temperature of 40 to 50 degrees Celsius.

7. Apparatus a claimed in claim 1, wherein the sample chamber includes an inlet port, an exhaust port, a check valve adapted to prevent the escape of breath sample from the sample chamber through the inlet port, and a liquid detector adapted to prevent saturation of the breath alcohol detector.

8. Apparatus as claimed in claim 7, wherein the heating means comprise a heater block adapted to be heated to a desired temperature by a heating transistor together with a temperature sensor adapted to detect the temperature of the heater block, and the sample chamber is mounted on the heater block so that in use an even heat distribution is provided aςross the chamber extending to the inlet and exhaust ports.

9. Apparatus as claimed in claim 7, wherein an exhaust tube is attached to the exhaust port and adapted to permit a volume of the breath sample, in excess of that required for analysis, to be exhausted therethrough.

10. Apparatus as claimed in claim 1, wherein the sample chamber includes means for measuring pressure or volume of the breath sample.

11. Apparatus as claimed in claim 1, which further includes signalling means adapted to send a signal to a vehicle to whiσh the apparatus is connected so that operation of the vehicle is affected if the alcohol in the breath sample exceeds a predetermined limit.

12. Apparatus as claimed in claim 11, wherein the apparatus is permanently connected to the vehicle.

13. Apparatus as claimed in claim 11, wherein the apparatus is removably connected to the vehicle.

14. Apparatus as claimed in claim 11, wherein the signalling means includes an infra-red or radio frequency transmitter adapted to send a signal to a receiver mounted on or in the vehicle.

15. Apparatus as claimed in claim 14, wherein the receiver is interfaced with an electronic control system in the vehicle, the system being adapted to prevent starting of the vehicle if the predetermined limit is exceeded.

16. Apparatus as claimed in claim 14, wherein the receiver is interfaced with an electronic control system in the vehicle, the]system being adapted to generate a warning if the predetermined limit is exceeded.

17. Apparatus as claimed in claim 16, wherein the electronic control system is further adapted to shut down the vehicle after a predetermined period of time after generation of the warning.

18. Apparatus as claimed in claim 1 substantially as herein described with reference to Figs 1 and 2 of the Drawings.