Ultrasound probe assembly, system, and method that reduce air entrapment

A method comprising:

• urging an imaging end of an ultrasound probe assembly into a surface of a structure to be inspected, wherein the urging comprises urging a delay line of the ultrasound probe assembly into the surface of the structure;
• compressing the delay line into a compressed state against the surface of the structure, wherein the compressing operation changes the shape of the delay line;
• and
• purging air from the imaging end through the compressing operation.

An ultrasound probe assembly, comprising:

• a transducer configured to transmit and receive ultrasound signals in relation to a structure;
• a soft delay line coupled to the transducer, wherein the delay line is configured to change shapes between an uncompressed state and a compressed state, wherein compression of the delay line between the uncompressed and compressed states purges air from a space between the delay line and the structure into which the delay line is compressed, wherein the delay line is configured to conform to an outer surface of the structure as the delay line is compressed into the structure, wherein the delay line has a constant density throughout in the uncompressed state, wherein the delay line has a variable density throughout in the compressed state, and wherein the delay line comprises:
• (a) a transducer-coupling surface that couples to the transducer, wherein the transducer-coupling surface has a first shape in the uncompressed state, and (b) a structure-engaging surface that is configured to engage a surface of the structure, wherein the structure-engaging surface has a second shape in the uncompressed state, wherein the first shape differs from the second shape, wherein the soft delay line changing shapes from the uncompressed state to the compressed state causes the ultrasound signals transmitted from the transducer to change shape;
• a retainer positioned around an outer peripheral edge of the delay line, wherein the retainer is configured to maintain the delay line within an imaging envelope of the transducer during the uncompressed and compressed states;
• and
• a control unit operatively connected to the transducer, wherein the control unit is configured to phase signal pulses to each of the plurality of transducer elements based on the compression of the delay line.