| 摘要 |
PURPOSE:To make it possible to measure differential pressure in high sensitivity, by a method wherein pressure to be measured is introduced into a sensitive pressure converter in an alternating manner and the measurement is carried out from the signal obtained by subjecting the output thereof to AC amplification. CONSTITUTION:The pressure in a pipe 6 is acted on the pressure receiving surface of a sensitive pressure converter 7 such as a microphone and, into the pipe 6, pressures P1, P2 to be measured are alternately introduced through solenoid valves 1, 2 controlled in the opening and the closing thereof by a pulse imparted from a gate signal generator 5. The output of the converter 7 is multiplied by an alternating amplifier 8 to be added to a differential amplifier 9 in synchronous relation to the solenoid valves 1, 2 through gates 11, 12 and reduction filters 13, 14. The difference E2-E1 in the outputs of the reduction filters 13, 14 is generated to the output end of the differential amplifier 9 and the difference of the pressures P2, P1 to be measured is displayed. In addition, accumulators 3, 4 may be provided in order to remove the inertia of a fluid. |
