Hermetically sealed ultrasonic transducer system

A hermetically sealed, dry-coupled transducer system for measuring the position of a reflective surface in a target element, said system having a shell with forward and rearward apertures, an acoustic window covering said forward aperture, a transducer element with forward and rear surfaces and positioned within said shell to transmit acoustic signals from said forward surface to said element and to receive reflections back therefrom, backing structure for dry-coupling mechanical force to hold said transducer in good acoustic contact with said element, and a disc assembly with holes positioned contiguous to said transducer back surface, said disc assembly providing substantially uniform transmission of mechanical force to said transducer rear surface and providing a plurality of air gaps configured so as to substantially block acoustic transmission from said transducer to the backing structure, said system comprising:

• a hermetic seal at the junction of the window and the shell and a push rod enclosing the rearward aperture, said push rod comprising a push rod hermetically coupled to a thin, compliant, threaded cap, said cap providing means for repetitively coupling and uncoupling the push rod to and from the shell.

A hermetically sealed, dry-coupled transducer system for measuring the position of a reflective surface in a solid target element with a crack therein, said system having a shell with forward and rearward apertures, an acoustic window covering said forward aperture, a transducer element with forward and rear surfaces and positioned within said shell to transmit acoustic signals from said forward surface to said element and to receive reflections back therefrom, backing structure for dry-coupling mechanical force to hold said transducer in good acoustic contact with said element, and a disc assembly positioned contiguous to said transducer back surface, said disc assembly providing substantially uniform transmission of mechanical force to said transducer rear surface and providing a plurality of air gaps configured so as to substantially block acoustic transmission from said transducer to the backing structure, said system comprising:

• a hermetic seal at the junction of the window and the shell and a push rod enclosing the rearward aperture, said push rod comprising a push rod hermetically coupled to a thin, compliant, threaded cap, said cap providing means for repetitively coupling and uncoupling the push rod to and from the shell;
• and
• means for deriving from said received reflections and indication of the position of said crack.