Abstract: A system and a method for determining the leakproofness of an object having a first cavity. The system includes a closed chamber having a second cavity arranged to envelope the object, an evacuator for lowering the pressure inside one of the cavities, a supply for supplying a tracer gas into the one of the cavities rendered the higher pressure, a detector sensitive to the tracer gas and an introducer for introducing a transport gas into the one of the cavities rendered the lower pressure. Furthermore, the evacuator is arranged to compress arriving gas to the ambient pressure of the chamber and to communicate with the detector, which is suited for operation at the ambient pressure of the chamber. The tracer gas includes hydrogen.

Abstract: A system and a method for determining the leakproofness of an object having a first cavity. The system includes a closed chamber having a second cavity arranged to envelope the object, an evacuator for lowering the pressure inside one of the cavities, a supply for supplying a tracer gas into the one of the cavities rendered the higher pressure, a detector sensitive to the tracer gas and an introducer for introducing a transport gas into the one of the cavities rendered the lower pressure. Furthermore, the evacuator is arranged to compress arriving gas to the ambient pressure of the chamber and to communicate with the detecting means, which is suited for operation at the ambient pressure of the chamber. The tracer gas is hydrogen.

Abstract: The present invention relates to a method at detection of presence of hydrogen gas and measurement of content of hydrogen gas. The detection is performed by means of a hydrogen gas sensitive semiconductor sensor, whose output signal is used for determination of the content of hydrogen gas in the gas sample. The semiconductor sensor is exposed to the gas sample during a detection interval, which is preceded by a time-interval of preconditioning treatment during which the semiconductor sensor is exposed to a surrounding gas atmosphere. The invention is characterized in that the gas atmosphere contains a negligible amount of oxygen, hydrogen and carbon monoxide compared to the gas sample and that the time interval is many times longer than the detection interval.