Westinghouse Electric Corporation

Westinghouse Electric Company LLC

Jennifer E Michaels

Lawrence D Nottingham

Thomas E Michaels

The present invention includes a bore mapping system that includes one or more high resolution ultrasonic mapping transducers that are used to measure the diameter of a bore. The travel time for a normally incident pulse to reach the bore surface and return for each transducer is used with a reference reflection time measured in a calibration bore to determine the measured diameter from a mechanically measured reference diameter using a known velocity of the ultrasonic pulse in an immersion fluid. The diameter measured by each of the transducers is averaged to obtain an average measured diameter which is produced for plural axial rotor positions. The present invention also includes a surface time measurement system that uses at least one ranging transducer measuring the ranging time required for a ranging beam to reach and return from the bore surface. The measured ranging time is used with a calibrated ranging time obtained in the calibration bore to modify a calibrated inspection beam surface time for an inspection transducer to obtain a current inspection beam surface time. The ranging time can also be used to obtain a correction time curve that provides correction time for the inspection beam surface time versus circumferential bore position. The calibrated inspection beam surface time or the correction time curve, are used to correct positions of flaws in the rotor material.

Bore mapping and surface time measurement system

An immersion base ultrasonic inspection system for interrogating the bore and near bore material of turbine and generator rotors by passing ultrasonic search units through the rotor bore. This system utilizes variable focus array inspection transducers in a shear mode inspection of the near bore material. The system includes a positioning assembly for a transducer which includes carriage means for supporting the transducer and a first positioning means for tilting one end of the carriage means in a radial axial plane whereby the transducer may be positioned at an angle to a longitudinal axis of the system. A second positioning means is provided for circumferentially rotating the transducer to a known and repeatable angular position. Position resolver means are coupled to the first and second positioning means.

Positioning assembly for a transducer in a boresonic inspection system

An immersion based ultrasonic inspection system is disclosed which is used to interrogate the bore and near bore material of turbine and generator rotors by passing ultrasonic search units through the rotor bore. This system utilizes variable focus array inspection transducers in a shear mode inspection of the near bore material. The flaw location method includes recording calibration transit times and transducer locations for calibration holes from which refraction angles, and material velocities are determined. When a flaw is detected the surface time for a bore surface reflection, the flaw reflection time and transducer position are used to determine the position of the flaw.

Boresonic inspection system

An ultrasonic signal processing system that includes flaw gates that process signals from an inspection transducer is disclosed. The flaw gates operate in pairs where each pair is dedicated to a time window corresponding to, for example, flaw depth or transducer angle. The time window for a pair of flaw gates is indicated by a channel code produced by a timing control unit. One flaw gate in each pair processes incoming digitized transducer signals during a scan to produce reflector indications while the other gate in each pair transfers data from a previous different position scan to a main computer. The main computer determines flaw locations from the reflector indications and transducer positions provided by the flaw gate. The flaw gates each adjust reflector indication location signals for changes in distance between an immersed ultrasonic wave inspection transducer and the surface of the material being inspected as well as record the location of the inspection transducer at the time of each indication detection. The flaw gates produce the indication by comparing the digitized transducer signal waveform with a threshold curve where an indication is an excursion of the signal waveform above the threshold. The flaw gates each contain a comparator that indicates when the window is open and activates a waveform memory that automatically stores the digitized transducer signals during the window.

Ultrasonic signal processing system including a flaw gate

An immersion based ultrasonic inspection system is disclosed which is used to interrogate the bore and near bore material of turbine and generator rotors by passing ultrasonic search units through the rotor bore. This system utilizes variable focus array inspection transducers in a shear mode inspection of the near bore material. A ranging transducer is provided which is used to correct the surface time of the inspection beam. A mapping transducer and blind bore sensor allow diameter mapping of the rotor bore as well as a blind rotor end sensing as the scan head carrying the transducers enters the bore. A scan head centering device or chuck deploys four radial arms to center and support the scan head. Each arm has a roller attached to the end which contacts the bore and rolls along so that the bore will not be damaged as the scan head passes through the bore. The chuck is driven by an electric motor and coupled to a resolver allowing the chuck to be adjusted according to bore geometry mapped by the mapping transducer. The chuck includes a pneumatic disengagement device for fail-safe disengagement of the centering arms to allow retrieval of the scan head in the event of motor or wiring failure. The chuck also includes cable pathways for control cables for the various scan head motion axes. An inspection transducer carriage is provided that provides three axes of motion to the inspection transducer. A radial motion is provided by two radial support assemblies driven by an electric motor and coupled to a resolver allowing radial position to be accurately determined.

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Freeville, NY, United States of America

Jennifer E Michaels