The subject matter disclosed herein relates to a phased array ultrasonic scanner and, in particular, to a rolling phased array ultrasonic scanner.
Nondestructive inspection devices can be used to inspect test objects and to detect and analyze anomalies, defects and characteristics therein. Nondestructive inspection allows a technician to maneuver a probe on or near the surface of the test object in order to perform testing of both the object surface and its underlying structure. One example of a nondestructive inspection apparatus is an ultrasonic scanner.
A rolling ultrasonic scanner is one type of scanner that is used to provide an image of an object or part to reveal flaws, defects, characteristics, or anomalies in the object. A rolling ultrasonic scanner includes a cylindrical rotating portion, or wheel, filled with an acoustically transmissive fluid such as water or propylene glycol. The fluid enables coupling of ultrasonic signals emitted by a transducer unit within the cylinder with the object being inspected. In many instances, the rolling ultrasonic scanner is a hand held apparatus that the user manually rolls across the object under test to produce data from the object.
In operation, electrical pulses are transmitted to the transducer unit. The transducer unit transforms the electrical pulses into ultrasonic waves using one or more ultrasonic transducers (e.g., piezoelectric elements) arranged in an array within the scanner. The ultrasonic waves generated by the transducers are transmitted into the test object to which the scanner is coupled. As the ultrasonic waves pass into the test object, various reflections, called echoes, occur as the ultrasonic waves interact with anomalies and other physical characteristics in the test object. Conversely, when the reflected ultrasonic waves are received by the piezoelectric surface of the ultrasonic transducers, it causes the transducers to vibrate which generates a voltage difference across the transducer electrodes that is detected as an electrical signal by signal processing electronics connected to the transducers through the cable. The signal processing circuits track the time difference between the transmission of the electrical pulses and the receipt of the electrical signals, and measure the amplitude of the received electrical signals to determine various attributes of any anomalies and characteristics of the object, such as depth, size, location, and orientation.
A phased linear array ultrasonic scanner has a plurality of electrically and acoustically independent ultrasonic transducers in a single linear array. By varying the timing of the electrical pulses applied to the ultrasonic transducers using delay criteria, a phased linear array ultrasonic probe can generate ultrasonic waves passing into the test object at different angles (e.g., from zero to one hundred eighty degrees) to try to detect anomalies and variances therein and to identify the orientation of those anomalies and variances. For example, to generate an ultrasonic wave at thirty degrees, the transmit delays for the ultrasonic transducers of the phased array ultrasonic probe can be set in a first configuration of values. To then generate an ultrasonic wave at thirty-two degrees, for example, the transmit delays for the ultrasonic transducers of the phased array ultrasonic probe can be set in a second configuration of values. This sequential generation, transmission, and receipt of the ultrasonic waves at each of the different angles is quite time consuming and results in a longer inspection time of the test object, especially if a one hundred eighty degree scan is required at different locations on the test object. While a linear scan provides efficient detection of corrosion or delamination, for example, those flaws are typically parallel to the entry point, i.e., where the ultrasonic waves enter the test object. Therefore, flaws oriented at different unknown angles require a time consuming procedure to insure that they are detected.
The discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter.