Claims
- 1. An inspection station for examining a girth weld section of a thin walled tube, said inspection station comprising, in combination:
- A. means for conveying the tube into and out of said inspection station;
- B. means for arresting the conveyance of the tube into said inspection station such as to position the weld section at an axial reference position;
- C. means for rotating the tube in said reference position about its axis;
- D. an ultrasonic transducer;
- E. means for translating said ultrasonic transducer over a path parallel to the axis of the rotating tube, whereby to execute a predetermined scanning pattern consisting of a multiplicity of axially spaced, circumferential scan lines encompassing the weld section;
- F. means for pulsing said ultrasonic transducer to emit ultrasonic weld section-probing energy at a multiplicity of data points distributed along said scan lines throughout said scanning pattern;
- G. an angular position encoder driven in synchronism with said tube rotating means for controlling said ultrasonic transducer pulser means and said ultrasonic transducer translating means, whereby to establish the locations of said data points relative to the weld section;
- H. means for developing echo signals from the reflections of said ultrasonic probing energy at each said data point;
- I. means for detecting said echo signals to derive thickness data indicative of the weld section thickness at each said data point and amplitude data indicative of the presence of any weld section included feature at each said data point, said thickness data being derived utilizing
- 1) a first discriminator for detecting probing energy reflections from the outer surface of the weld section,
- 2) a second discriminator for detecting probing energy reflections from the inner surface of the weld section, and
- 3) a first converter responsive to said first and second discriminators for converting the time interval between the detections of said outer and inner surface energy reflections into said weld section thickness data; and
- J. means for analyzing said thickness and amplitude data for all of said data points to
- 1) find the amplitude data of maximum magnitude for each distinct weld section included feature and determine whether any of said maximum magnitude amplitude data indicates an included feature size in excess of an acceptable limit, and
- 2) find the minimum thickness of the weld section and determine whether said minimum thickness is less than an acceptable limit.
- 2. The inspection station defined in claim 1, wherein said scanning pattern is of a spiralled configuration consisting of plural helical scan lines.
- 3. The inspection station defined in claim 2, wherein said ultrasonic transducer translating means includes a stepping motor controlled by said encoder to index said ultrasonic transducer over said path at predetermined angular increments during each tube revolution, whereby each said helical scan line consists of a multiplicity of axially stagger, peripheral scan segments.
- 4. The inspection station defined in claim 1, wherein said echo signal detecting means further includes a peak detector for detecting the maximum peak amplitude of a probing energy reflection caused by any included feature and occurring in the time interval between said outer and inner surface energy reflections, the maximum peak amplitude detection being converted to said included feature amplitude data.
- 5. The inspection station defined in claim 4, wherein said echo signal detection means further includes a second converter responsive to said first discriminator and said peak detector for converting the time interval between the detection of said outer surface energy reflection and the detection of any energy reflection caused by an included feature into depth data indicative of the location of a feature as measured from the outer surface of the weld section.
- 6. The inspection station defined in claim 5, wherein said data analyzing means normalizes said included feature maximum magnitude amplitude data for a given data point using said feature depth data for said given data point.
- 7. The inspection station defined in claim 6, wherein said echo signal detecting means further includes means for delaying and amplifying said echo signal as applied to said peak detector, and gate generator means responsive to said first discriminator for generating an inspection window during said time interval between said inner and outer surface energy reflections during which said peak detector can detect included feature energy reflections in said delayed and amplified echo signals.
- 8. The inspection station defined in claim 6, wherein the weld section joins an end plug to one open end of the tube, said conveying means conveying the tube axially into said inspection station, and said tube arresting means includes a line centering stop against which the end plug is abutted to establish the weld section axial reference position.
- 9. The inspection station defined in claim 8, wherein said data analyzing means analyzes said thickness data to determine the degree of penetration into the tube open end of the weld joining the end plug thereto.
- 10. The inspection station defined in claim 9, wherein said data analyzing means is programmed to
- 1) analyze said thickness data over each full scan line to determine the gross weld section cross sectional area thereat,
- 2) analyze said amplitude data for each included feature to determine the feature dimension along each said scan line and square each said determined feature dimension to calculate the feature cross sectional area included in each said scan line, and
- 3) substract said feature cross sectional area from said gross weld cross sectional area for each said scan line to determine the net weld section cross sectional area thereat.
Parent Case Info
This is a divisional of copending application Ser. No. 07/250,187, filed on Sept. 28, 1988 pending.
US Referenced Citations (7)
Foreign Referenced Citations (2)
Number |
Date |
Country |
0006066 |
Dec 1979 |
EPX |
0047197 |
Apr 1977 |
JPX |
Divisions (1)
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Number |
Date |
Country |
Parent |
250187 |
Sep 1988 |
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