selective gasdetektion by feldseparation and schallgeschwindigkeitsmessung: oxygen detection.

摘要

PCT No. PCT/CH90/00277 Sec. 371 Date Jun. 17, 1993 Sec. 102(e) Date Jun. 17, 1993 PCT Filed Nov. 30, 1990 PCT Pub. No. WO91/09306 PCT Pub. Date Jun. 27, 1991.A method and apparatus for selective detection of gases and vapors uses paramagnetic and electric dipole moments. An inhomogeneous magnetic field (31, 32, 33, 33') or an inhomogeneous electric field (41, 42, 43, 43', 44, 44') through the gas sample causes molecule enrichment in the acoustically sensitive range (34) of an ultrasonic resonator (1). The ultrasonic resonator has mutually opposed ultrasonic transducers operating as a transmitter (2) and a receiver (3). Because of the change in acoustic velocity, the molecule enrichment causes detuning of the ultrasonic resonator (1) and hence a change in signal at the receiving transducer (3). The method is particularly sensitive to the detection of oxygen.