| 摘要 |
PURPOSE:To certainly detect the rubbing of a rotary machine, by mounting two acoustic sensors having almost equal vibration sensitivity characteristics to the mutually contacted places of the rotary machine and subjecting the outputs of the sensors to operational processing. CONSTITUTION:A pulse generator 3 for generating a pulse 3a synchronous with the rotary shaft 1a of a rotary machine 1 is mounted on the upper metal fitting 101 of a metal bearing jig 1C supporting said rotary shaft 1a and one end of each of the wave guides 10a, 11a is attached respectively to the lower metal fitting 102 of the metal bearing jig 1C and the bearing seat 1f supporting the lower metal fitting 102, to be separately connected to acoustic sensors 10, 11 each using a piezoelectric element outside a casing 1d. The outputs of the acoustic sensors 10, 11 are amplified by amplifiers 4, 12 and passed through band-pass filters 5, 13 to be detected by envelope detectors 6, 14 respectively. Both detection outputs are amplified by a differential amplifier 15 and subjected to averaging operation for a predetermined time on the basis of the pulse 3a by an average value operator 7 to be displayed on CRT8. By this method, the collisional vibration signal between the lower metal fitting 102 and the bearing seat 1f is removed to make it possible to surely detect rubbing.
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