Abstract: A human ventilatory capacity measurement instrument, of the kind which measures the peak flow rate of a single forced expiration, comprises a hollow cylindrical body housing a coaxial rod on which is carried a piston spring-biased in one longitudinal sense. The body is longitudinally slotted and has an indicator engaged in the slot for movement therealong by the piston when blown against its spring bias, but the indicator is returned to its starting position in the slot by independent movement. A scale is provided alongside the slot to give a measure of peak flow rate by the final rest position of the indicator when pushed by the piston.

Abstract: Apparatus for detecting alcohol vapour in a gas, such as exhaled breath. The apparatus comprises a detachable mouthpiece through which a person exhales. The mouthpiece includes a vent for venting some exhaled breath to atmosphere and an outlet port connected to a sensor which provides an electrical output dependent upon the amount of alcohol in the breath sample. A piston and cylinder valve assembly is provided for introducing a predetermined amount of the sample into the sensor at a time dictated by an operator. A calibrated meter, which may be analogue or digital is connected to the sensor to indicate the amount of alcohol in the sample.