Method and apparatus for ultrasonic flaw detection

Claim 1

An ultrasonic flaw detection method for detecting internal cavity defects in a material, characterised in that said method comprises: providing on a rotary body a plurality of probes in equidistant positions in the circumferential direction of said rotary body,said probes forming part of a plurality of channels to transmit and receive ultrasonic pulses along respective paths which intersect the axis of rotation of said rotary body at different depths in an inspection zone within the material when positioned opposite to said probes; turning said rotary body to revolve said probes through 360 0 about said axis of rotation while transmitting and receiving said ultrasonic pulses; producing detected flaw patterns for each respective direction of incidence of said ultrasonic beams, from the peak values of the echoes received by the respective channels ; and deciphering the direction, inclination, size and depth of a detected defect from correlation processing of said detected flaw patterns with a number of predetermined reference patterns to judge the severity of the detected defect.

Claim 3

An apparatus for ultrasonic flaw detection for recognising internal cavity defects in a material, characterised in that said apparatus comprises: a plurality of probes (14-17, 201, 316-319) mounted on a rotary body (13, 211, 315) in equidistant positions in the circumferential direction of said rotary body for providing a plurality of channels for transmitting and receiving ultrasonic pulses along respective paths (14a-17a, 14b-17b) which intersect the axis of rotation (00') of said rotary body (13, 211, 315) at different depths in an inspection zone within the material (2) when positioned opposite said probes (14-17, 201, 316-319); drive means (18-21, 212, 320, 321) for turning said rotary body (13, 211, 315) to revolve said probes (14-17, 201, 316-319) through 360° about said axis of rotation (00') while transmitting and receiving said ultrasonic pulses; peak-holding and memory means (37-40, 217, 332-335) provided for each one of said channels (CHl - CH4) for producing and storing detected flaw patterns for each direction of incidence of said ultrasonic beams from the peak values of echoes received by the respective channels; a correlator (41-48) for deciphering the direction, inclination, size and depth of said detected defect by correlation processing of said detected flaw patterns with a number of predetermined reference patterns; and means for judging the severity of the detected defect according to the results of said correlation processing.

Claim 4

An apparatus for ultrasonic flaw detection for recognising internal cavity defects in a material, characterised in that said apparatus comprises: a plurality of probes (14-17, 201, 316-319) mounted on a rotary body (13, 211, 315) in equidistant positions in the circumferential direction of said rotary body for providing a plurality of channels for transmitting and receiving ultrasonic pulses along respective paths (14a-17a, 14b-17b) which intersect the axis of rotation (00') of said rotary body (13, 211, 315) at different depths in an inspection zone within the material (2) when positioned opposite said probes (14-17, 201, 316-319); drive means (18-21, 212, 320, 321) for turning said rotary body (13, 211, 315) to revolve said probes (14-17, 201, 316-319) through 360° about said axis of rotation (00') while transmitting and receiving said ultrasonic pulses; peak-holding and memory means (37-40, 217, 332-335) provided for each one of said channels (CHl - CH4) for producing and storing detected flaw patterns for each direction of incidence of said ultrasonic beams from the peak values of echoes received by the respective channels; a correlator (41-48) for deciphering the direction, inclination, size and depth of said detected defect by correlation processing of said detected flaw patterns with a number of predetermined reference patterns; and means for judging the severity of the detected defect according to the results of said correlation processing.

Claim 8

An apparatus as claimed in any of claims 2 to 4 wherein said detection gate (14b-17b) of each channel (CH1-CH4) is connected to said-correlator (41-48) through a signal processor (111-121) including a signal pre-processing circuit comprising: a high resolution analogue to digital converter (113) for converting analogue input signals into digital signals; a buffer register (114) for storing said digital signals; a digital peak holding circuit (115) for holding the peak value of said digital signals; a shift register (116) for storing said peak value and adapted to repeat a shift until data becomes absent in a number of bits as determined by the resolution of a succeeding stage; a counter (120) for counting the number of shifts of said shift register (116); and a data selector (121) for compressing the data in said buffer register (114) from an upper position according to the output count of said counter (120) to select said data by a number of bits conforming with the resolution of said succeeding stage; whereby the selected data is transferred to said succeeding stage separately by a significant digit part and an exponent of 2 corresponding to said output count of said counter (L20) -

Claim 11

An apparatus for ultrasonic flaw detection for recognising internal cavity defects in a material, characterised in that said apparatus comprises: either aplurality of probes (14-17, 316-319) mounted on a rotary body (13, 315) spaced at different distances from the axis of rotation (00') of said rotary body (13, 315) or one probe(201) movable by means (409-432) to positions of varying spacing from said axis (00') of rotation to provide a plurality of channels for transmitting and receiving ultrasonic pulses along paths (14a-17a, 14b-17b) which intersect the axis of rotation (00 1 ) of said rotary body (13, 211,315) at different depths in an inspection zone within the material (2) when positioned opposite said probe(s) (14-17, 201, 316-319) the depth depending upon the spacing of said probe(s) from the axis of rotation (OO'); drive means .(18-21, 212, 320, 321) for turning said rotary body (13, 211, 315) to revolve said probe(s) (14-17, 201, 316-319) through 360° about said axis of rotation (00 1 ) while transmitting and receiving said ultrasonic pulses; peak holding and memory means (37-40, 217, 332-335) provided for each one of said channels (CHl-CH4) for producing and storing detected flaw patterns for each direction of incidence of said ultrasonic beams from the peak values of echoes received by the respective channels; a correlator for deciphering the direction, inclination, size and depth of said detected defect by correlation processing of said detected flaw patterns with a number of predetermined reference patterns; and means for judging the severity of the detected defect according to the results of said correlation processing.

Claim 12

An apparatus for ultrasonic flaw detection for recognising internal cavity defects in a material, characterised in that said apparatus comprises: either aplurality of probes (14-17, 316-319) mounted on a rotary body (13, 315) spaced at different distances from the axis of rotation (00') of said rotary body (13, 315) or one probe(201) movable by means (409-432) to positions of varying spacing from said axis (00') of rotation to provide a plurality of channels for transmitting and receiving ultrasonic pulses along paths (14a-17a, 14b-17b) which intersect the axis of rotation (00 1 ) of said rotary body (13, 211,315) at different depths in an inspection zone within the material (2) when positioned opposite said probe(s) (14-17, 201, 316-319) the depth depending upon the spacing of said probe(s) from the axis of rotation (OO'); drive means .(18-21, 212, 320, 321) for turning said rotary body (13, 211, 315) to revolve said probe(s) (14-17, 201, 316-319) through 360° about said axis of rotation (00 1 ) while transmitting and receiving said ultrasonic pulses; peak holding and memory means (37-40, 217, 332-335) provided for each one of said channels (CHl-CH4) for producing and storing detected flaw patterns for each direction of incidence of said ultrasonic beams from the peak values of echoes received by the respective channels; a correlator for deciphering the direction, inclination, size and depth of said detected defect by correlation processing of said detected flaw patterns with a number of predetermined reference patterns; and means for judging the severity of the detected defect according to the results of said correlation processing.