Breath sampling device

1. A breath sampling device comprising a hollow container defining a sample chamber and formed of at least two parts which fit together and have apertures therein;

wherein at least one of said parts is displaceable relative to the other part or parts between a first relative disposition of the parts in which the apertures are open so as to provide a clear path for air to pass through the container, and a second relative disposition of the parts in which the apertures are closed so that there is no path for air to pass through and a volume of air is trapped in the chamber;

wherein the container comprises first and second tubular parts, each having side walling and respective end closures, the side walling of the first tubular part having an aperture therein and being a close fit within the side walling of the second tubular part, so that said side walling aperture is respectively uncovered and covered by the side walling of the second tubular part as the parts are moved between their first relative disposition and their second relative disposition; and

wherein the respective end closures of the first and second tubular parts lie at a common end of the sample chamber and each end closure has at least one aperture therein which is opened and closed, respectively, as the parts are moved between their first relative disposition and their second relative disposition.

2. A device as claimed in claim 1 wherein the side walling of the second tubular part also has an aperture therein, the respective apertures in the side walling of the first and second parts being moved into and out of register as the parts are moved between their first relative disposition and their second relative disposition.

3. A device as claimed in claim 1 wherein the first and second tubular parts are cylindrical and relatively rotatable between their first relative disposition and their second relative disposition and the apertures in their respective end closures are moved into and out of alignment as the parts are so rotated.

4. A device as claimed in claim 1 wherein the first and second tubular parts are axially moveable relative to each other.

5. A device as claimed in claim 1 wherein the first tubular part is pivotable relative to the second tubular part so as to swing apart from the second part to move from the second relative disposition of the parts wherein the apertures are closed to the first relative disposition of the parts wherein the apertures are open.

6. A device as claimed in claim 1 further comprising, within the sample chamber, an indicator which is capable of providing a detectable indication, by change of color or color intensity, of the presence of a given substance in a gas sample contained in said chamber, the indicator being mounted inside the sample chamber in such a manner that only a part of the indicator is exposed to gas within the sample chamber and part thereof is unexposed so that there will be a boundary between the exposed and unexposed parts after the former has been held in contact with gas trapped within the chamber.

7. A device as claimed in claim 6 wherein the indicator is mounted inside the sample chamber in such a manner that only a central part thereof is exposed to gas within the sample chamber and a surrounding peripheral part thereof is unexposed.

8. A device a claimed in claim 7 , wherein an end cap is provided on one of the tubular parts and the indicator is mounted inside the end closure and/or the end cap of the container.