SONIC APPARATUS AND METHOD FOR DETECTING THE PRESENC OF A GASEOUS SUBSTANCE IN A CLOSED SPACE

摘要

A method of and apparatus for detecting the presence of a gaseous substance within a space (12) bounded by an enclosure (10) utilises the fact that sound is not transmitted through a vacuum and is transmitted through the material of the enclosure (10). A sonic wave transmitter (2) and a sonic wave receiver (4) are engaged with the material of the enclosure (10) and separated by the space (12). Using calculated arrival times and/or amplitudes for soundwave portions travelling through the space (12) and through the material of the enclosure (10), it can be determined whether a soundwave portion has passed through the space (12) and thus a leakage of gaseous substance into the space (12) above a threshold amount has taken place.