Ultrasonic transducer probe expansion chamber

An ultrasonic transducer probe comprising:

• a forward located assembly including a pivotally mounted ultrasonic transducer;
• a motor, located to the rear of and connected to said assembly, for controllably moving the transducer to radiantly transmit ultrasonic energy;
• and
• an acoustic couplant fluid chamber, enclosing said motor and assembly and including a cap assembly defining a forward hemispheric fluid compartment containing said transducer at the forward end, a rearward located cylinder defining a rearward fluid compartment and having a sealed rearward end and an open forward terminus, and a flexible, cylindrical bellows in fluid-tight connection between said cap assembly defining said hemispheric fluid compartment and said open forward terminus of said cylinder which defines an intermediate fluid compartment of sufficient cross-sectional area to enclose said motor, said cap assembly, bellows, and cylinder defining a contiguous longitudinal acoustic couplant fluid chamber, wherein said bellows comprises means for restricting volumetric variation of said acoustic couplant fluid chamber in response to thermal expansion and contraction of said fluid to longitudinal volumetric variation of said chamber.