Pressure wave generator with movable control rod for generating a pressure wave in a medium

A pressure wave generator for generating a pressure wave in a medium, the pressure wave generator comprising:

• a movable piston having a first surface and a second surface and a longitudinal axis between the first surface and the second surface, the piston comprising a guide extending along the longitudinal axis of the piston from the first surface at least partially toward the second surface;
• a housing having an inner bore, a first end, and a second end, the piston being at least partially disposed within the inner bore of the housing, the piston movable within the inner bore of the housing from the first end toward the second end along a direction parallel to the longitudinal axis of the piston;
• a control rod extending longitudinally from a first end to a second end, the second end of the control rod configured to be inserted in the guide and able to move within the guide without being displaced from the guide during movement of the piston within the inner bore;
• a transducer slidably accommodated in the second end of the housing, the transducer configured to be coupled to the medium and adapted to convert a portion of the kinetic energy of the piston into a pressure wave in the medium upon impact of the piston with the transducer;
• a retainer that is removably attached to the second end of the control rod, the retainer having a first orientation permitting the retainer to be inserted into the guide, the retainer movable to a second orientation when disposed in the guide, wherein when the retainer is in the second orientation and attached to the control rod, the retainer is configured such that moving the retainer into the first orientation is prohibited by the rod and the retainer is prevented from being displaced from the guide;
• a motive force generator configured to accelerate the movable piston toward the transducer;
• and
• an impact detection system configured to detect impact of the piston with the transducer and a position of the transducer,
• wherein on impact of the piston and the transducer, the second end of the control rod moves along a longitudinal axis of the guide toward the second surface of the piston.