Ultrasonic transducer with coupling means

Claim 1

Apparatus for providing an extended liquid coupling to a body under ultrasonic test, comprising: an elongated housing of substantially tubular internal section incorporating in sequence, an inlet adapted to receive coupling liquid from a pressurized source, a diffuser disposed within said housing and comprising a substantially cylindrical member having one end closed and an outwarDly extending annular wall at its other inlet end in engagement with the internal wall of said housing, the side wall of said substantially cylindrical member having a plurality of restrictive apertures extending generally normal to the axis of the interior of said housing for equalising liquid pressure across the housing section downstream of said diffuser, an ultrasonic transducer disposed within the region of the housing downstream of the diffuser, and means for straightening the flow of liquid extending completely across the housing so as to produce laminar flow from an outlet of the housing which is provided with a restriction ensuring positive internal liquid pressure within the portion of the housing disposed inwardly of said outlet, the inlet and outlet being provided at opposite end regions of the housing and in axial alignment, so as to produce within the housing an overall liquid flow which is substantially unidirectional and thereby tend to avoid turbulence induced ultrasonic reflecting interfaces.