Non-invasive method for measuring gas pressure using sonic resonances

The Ultrasonic Pressure Detector (UPD) was developed to demonstrate a factory/field-deployable inspection technique for determining the gas pressure in the GBU-15/AGM-130 actuation system. The UPD system uses a pair of piezoelectric transducers, an IBM AT personal computer, and a computer-aided test package. The pair of transducers is magnetically coupled to the sealed vessels used in the actuator assembly. The first transducer forces a mechanical vibration while the second transducer senses motion. By making use of the resonant frequency of the gas in the vessel, a corresponding pressure is determined. It is noted that the UPD provides the only known method to test the pressure vessel of a pneumatic actuation system for proper charge. The UPD provides a quick, easy method to ensure that the hardware is flightworthy