Breathalyzer with an improved mouthpiece

CA 02463201 2007-10-22

26541-11^

Breathalyzer With an Improved Mouthpiece

The present invention relates to a breathalyzer.

A breathalyzer of this type is described in DE 195 45 794 C2, wherein within the mouth piece the stream of breath is divided into a main gas stream that flows directly to the environment and a test gas stream. The test gas stream passes through the device's sampling system and because of the structural configuration of the device is adjusted relative to the volumetric flow to a value that corresponds to the value obtained from known calibrating devices, so that it is possible to calibrate the sampling system under actual flow conditions. One disadvantage of this known breathalyzer is deficient hygiene and condensation of the stream of gas within the breathalyzer when the divided stream of test gas flows directly through the sampling system.

Another breathalyzer of this kind is described in EP 0 153 883 A2; using this known device, it is particularly difficult to install the mouthpiece that is of a circular cross section on the breathalyzer.

The present invention seeks to resolve the problem that results from the fact that for reasons of hygiene the mouthpiece must be replaced for each individual tested. This procedure should be as simple and as rapid as possible, since during enforcement operations many individuals have to be tested with a breathalyzer in a very short period of time, in particular at night, when visibility is very poor. The mouthpiece must be securely attached to the breathalyzer during the testing procedure in order that it does not become loose during testing. In addition, for reasons of hygiene it must be ensured that

CA 02463201 2008-10-03

2.6541-117 the breath that is exhaled is routed only into the mouthpiece and does not come into contact with the interior of the breathalyzer. When providing a breath sample, the individual being tested should only come into direct contact with the replaceable mouthpiece; the subject's lips should not come into contact with the breathalyzer itself.

Thus, it is the objective of the present invention to describe a breathalyzer that has been significantly improved with respect to handling, in particular with respect to manipulating the replaceable mouthpiece. At the same time, the present invention should for all practical purposes preclude any direct physical contact between the test subject and/or the exhaled breath sample and the breathalyzer itself.

The present invention makes it easier to manipulate the breathalyzer with respect to changing and installing the replaceable mouthpiece in the breathalyzer, which can be attributed in particular to the trapezoidal cross section of the mouthpiece, with the matching shape of the complementary holder on the breathalyzer.

In one broad aspect, there is provided breathalyzer with a mouthpiece that is configured as a pressure tube, with a bore for sampling a breath for an alcohol sensor, wherein the mouthpiece is of a trapezoidal cross-section that is complementary to a corresponding negative shape within a holder of the breathalyzer so as to ensure a flush fit for the mouthpiece, and the mouthpiece further having a stop that encircles the mouthpiece on the outside, in the peripheral direction of the cross-section, at least in sections, and which fixes the position of the mouthpiece in the longitudinal direction relative to the holder so that an induction channel for sampling the breath

CA 02463201 2008-10-03

2.6541-117 extends through the bore.

One particularly preferred configuration of the present invention is characterized in that the trapezoidal cross-section of the mouthpiece has two sides that are of equal length, and the bore in the mouthpiece for taking the breath sample is located in a shorter of the two parallel sides of the mouthpiece cross section. Another preferred embodiment is characterized in that the mouthpiece incorporates a stop that encircles it on the outside, in the peripheral direction, at least in part, and this establishes the correct position of the

2a

CA 02463201 2004-04-05 mouthpiece in the longitudinal direction relative to the holder, so that the breathalyzer induction channel through which the breath sample is taken passes exactly through the bore in the mouthpiece.

The present invention will be described in greater detail below on the basis of the drawings appended hereto. These drawings show the following:

Figure 1 : A diagrammatic representation of a breathalyzer;

Figure 2: a vertical cross-section on the line A-B shown in Figure 1.

Figure 1 shows a breathalyzer 7. Breathalyzersof this pipe are marketed, in particular, under the brand name Alcotest®. The replaceable mouthpiece 1 is inserted into the holder 6 and is made, for example, from a plastic such as polyethylene. The mouthpiece 1 incorporates a bore 10 through which the induction channel 8 extends into the stream of breath that is blown into the breathalyzer from the left-hand side in Figure 1. The pump 9 is so controlled that it conveys a breath sample from the stream of breath into the breathalyzer and thus into the alcohol sensor 5 by means of a sampling stroke, once the subject has blown a sufficient amount of breath through of the mouthpiece 1. The injection opening in the mouthpiece 1 is expanded in a circular shape in order to permit a good fit between the subject's lips. For the remainder, the mouthpiece 1 is of a trapezoidal cross-section (Figure 2) that is complementary to a corresponding negative shape of the holder 6 of the breathalyzer. It is preferred that the trapezoidal crosssection of the mouthpiece 1 have two equal sides and the bore 10 for taking the breath sample is located in a shorter of the two parallel sides of this cross-section.

CA 02463201 2004-04-05

At the outlet end of the mouthpiece 1, which is the right-hand end of said mouthpiece in

Figure 1, there is an outlet opening 2 with a diameter of approximately 4-5 mm.

Because of this, the stream of breath courses a back pressure within the mouthpiece 1, and this is detected by a pressure sensor 11. The pressure that is measured corresponds to a specific volumetric flow of breath, from which the volume of breath that has provided can be determined by time integration.

At least in the area of holder 6, the mouthpiece 1 is of a cross-section as has been described, the upper parallel side the holder 6 being approximately 9 mm long and the lower parallel side being approximately 4 mm long, the height of the trapezium amounting to approximately 10 mm. The holder 6 is formed as a negative shape to the shape of the mouthpiece 1. The mouthpiece can be guided reliably on to the three complementary side surfaces and is securely seated in the holder 6 thereby. In addition, the trapezoidal cross sectional shape of the mouthpiece 1 simplifies installation in the holder 6, so that the induction channel 8 extends as desired through the bore 10. The orientation of the mouthpiece 1 relative to the breathalyzer is thus clearly defined in every instance. Furthermore, an external stop 3 is provided especially to ensure the correct lateral position of the mouthpiece 1 within the holder 6; this stop encircles the cross section of the mouthpiece 1, at least in sections, in the peripheral direction, so that the mouthpiece 1 will only be joined to the holder 6 to form a perfect match when the induction channel 8 extends through the bore 10. The slot 3 thus fixes the correct lateral position of the mouthpiece 1 relative to the holder 6. The optionally available positioning pin 4 serves as an aid for correctly aligning the mouthpiece 1 for installation in the holder 6, particularly if the mouthpiece 1 is still packaged, for example, in foil

CA 02463201 2004-04-05 wrap. The positioning pin 4 is particularly helpful when tests are being carried out in poor light, and because, for reasons of hygiene, the mouthpiece 1 must still be partially packaged when the operator installs it on the holder 6. In addition, the positioning pin 4 serves as a stand-off holder for the test subject, so that the test subject's lips to not come into contact with the breathalyzer itself.

According to a preferred embodiment, the mouthpiece 1 and the holder 6 are configured so as to be symmetrical relative to the breathalyzer 7, so that the mouthpiece 1 can be installed in the holder 6 in two different positions that differ from one another by 180°, thereby permitting improved manipulation of the mouthpiece 1.