| 摘要 |
A radio frequency (RF) probe ( 10 ) for a nuclear magnetic resonance check weighing system produces a uniform magnetic field at the center of RF probe ( 10 ), has minimal sensitivity to electrical interference from external sources, shapes the magnetic field to minimize cross coupling from packages such as drug vials ( 22 ) not under test, and presents minimal airflow obstruction. RF probe ( 10 ) includes a coil ( 100 ) with a plurality of conductive loops ( 102, 104 ) having a rectangular cross section carried inside two opposing, rectangular cross section housings ( 106, 108 ), respectively. Housings ( 106, 108 ) are spaced apart and in parallel, creating an "open probe" configuration permitting a conveyor belt ( 28 ) carrying vials ( 22 ) whose contents are to be checked to pass between housings ( 106, 108 ), and allows airflow surrounding the vials ( 22 ) and conveyor belt ( 28 ) to pass substantially without obstruction. Conductive loops ( 102, 104 ) and the housings ( 106, 108 ) carrying them may be placed such that the longitudinal axis of coil ( 100 ) is oriented in either horizontal or vertical spatial relation with conveyor belt ( 28 ).
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