Abstract: The present invention is a pressure coupling chamber (1) developed for comparison calibrations of acoustic pressure-sensitive hydrophone (2) in the frequency range from Hz to 1 kHz. A hydrophone (2), reference receiver unit (3) and acoustic source (6) under test are acoustically coupled in the chamber through the air-filled medium inside the pressure coupling chamber (1). Acoustic sources (6) that are going to create acoustic pressure in the pressure coupling chamber (1), placed on the side walls of the chamber (1) to surround the pressure-sensitive active surface of hydrophone (2), are driven to create a hydrostatic pressure effect in the related frequency range in the chamber. Calibration of tested hydrophone (2) with comparison method is carried out by measuring the output voltages of tested hydrophone (2) and the reference receiver unit (3).

Abstract: The present invention is a pressure coupling chamber (1) developed for comparison calibrations of acoustic pressure-sensitive hydrophone (2) in the frequency range from Hz to 1 kHz. A hydrophone (2), reference receiver unit (3) and acoustic source (6) under test are acoustically coupled in the chamber through the air-filled medium inside the pressure coupling chamber (1). Acoustic sources (6) that are going to create acoustic pressure in the pressure coupling chamber (1), placed on the side walls of the chamber (1) to surround the pressure-sensitive active surface of hydrophone (2), are driven to create a hydrostatic pressure effect in the related frequency range in the chamber. Calibration of tested hydrophone (2) with comparison method is carried out by measuring the output voltages of tested hydrophone (2) and the reference receiver unit (3).

Abstract: Ultrasonic inspection system, method, and apparatus for subsurface ultrasonic inspection of curved objects. The inspection system includes an apparatus having a support structure for supporting a selected transducer and a selected acoustic mirror adapted for immersion in a coupling fluid. The total inspection path distance for the ultrasonic radiation includes a first portion defined by the transducer-to-mirror distance, and a second portion including the mirror-to-object distance. The first and second portions may be relatively adjusted within a constant total inspection path distance to focus the ultrasonic radiation at a desired subsurface depth. Selection of the transducer is at least partly dependent on subsurface depth of the desired inspection zone. Selection of the acoustic mirror is at least partly dependent on the selected transducer, the total inspection path distance, and curvature of the inspection object.

Abstract: Ultrasonic inspection system, method, and apparatus for subsurface ultrasonic inspection of curved objects. The inspection system includes an apparatus having a support structure for supporting a selected transducer and a selected acoustic mirror adapted for immersion in a coupling fluid. The total inspection path distance for the ultrasonic radiation includes a first portion defined by the transducer-to-mirror distance, and a second portion including the mirror-to-object distance. The first and second portions may be relatively adjusted within a constant total inspection path distance to focus the ultrasonic radiation at a desired subsurface depth. Selection of the transducer is at least partly dependent on subsurface depth of the desired inspection zone. Selection of the acoustic mirror is at least partly dependent on the selected transducer, the total inspection path distance, and curvature of the inspection object.