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

摘要

The concentric inner (14) and outer (16) tubes of a vaccum insulated steam injection pipe (10) have the separating space (12) sealed at the two ends by solid connection (20) and annular plug (18), at least one of which structures should conduct sonic waves at a predicatable speed. A pair of spring loaded arms (22,24) hold a piezo-electric sonic wave transmitting transducer (2) and receiving transducer (4) in contact with the inner and outer tube surfaces. The transducers are connecter respectively to a pulse generator (30) and an amplifier and filter (32). An oscilloscope (34) is used to analyse arrival times and/or waveform amplitudes for soundwaves travelling through the material of the enclosure (10) and through the space (12).