Image Number 3 for United States Patent #5594176.
An ultrasonic scan assembly for use in inspecting downhole gas pipes comprises a sensor section which rotates in relation to an end section that remains essentially level forming a rotating interface. The sensor section includes at least one ultrasonic transducer for transmitting interrogating pulses into a pipe wall and for receiving return pulses that are analyzed for determining the maintenance and repair needs of the gas pipe. Provided in the scan assembly is a rotary transformer for magnetically coupling signals, such as return pulse data or power, across the rotating interface of the scan assembly. The rotary transformer includes a primary winding on one section of the scan assembly and a secondary winding on another section of the scan assembly. The primary windings and secondary windings associated with respective sections of the scan assembly can be placed in parallel or concentric relationship.