Showing papers on "Internal rotary inspection system published in 2004"

Method and apparatus for temperature-controlled ultrasonic inspection

Abstract: A method and apparatus for temperature-controlled ultrasonic inspection of an object. The temperature of a coupling medium between an ultrasonic transducer and an object under inspection is controlled to be at a predetermined temperature for which the attenuation of the ultrasonic energy in the coupling medium is reduced compared to the attenuation at an ambient temperature. This improves the efficiency of ultrasonic energy transport between the ultrasonic transducer and the object. The temperature of the object is controlled to simulate operating conditions more closely. An ultrasonic inspection system includes a temperature controller operable to maintain the temperature of the coupling medium and/or an object under inspection at a set temperature.

An ultrasonic profiling method for sewer inspection

Abstract: This paper presents a novel approach for the internal inspection of sewers through the use of sonar techniques, generating enhanced 3D graphs which represent the inner sewer surfaces. These graphs not only show the inner contour of the pipe but also integrate the intensity of the received echoes. The enhanced profile is generated by superimposing the peak intensity from the returning echoes at the calculated x, y and z coordinates where they are reflected from the pipe wall. These coordinates are calculated by measuring the time of flight of the first reflections, which are extracted from consecutives B-mode images generated during the ultrasonic scanning of the pipe. The proposed method has been capable of showing anomalous conditions, inside pipes filled with liquid, with dimensions smaller than the theoretical lateral and axial resolution of the transducer, in contrast to traditional methods where these kinds of defects were not detected. The proposed inspection method and its capabilities were validated through the realization of simulations and experiments. The simulations were conducted to validate the proposed method and explore its limitations. The proposed approach was particularly developed with the aim of scanning internal sections of sewers or water pipes filled with liquid using rotary ultrasonic sonars where visual methods could not be employed. It is expected that this research could also be expanded to the inspection of other submerged structures, such as water tanks, or pressurized vessels.

Non-Contact Tube Inspection Technique Using Laser Generation of Guided Wave and Its Reception by Air-Coupled Transducer

Abstract: Ultrasonic guided wave has been widely used for the tube inspection. The conventional method is to use piezoelectric transducers that should be contacted to the target surface. In recent years, however, the non-contact method is strongly required in the automation of inspection process for the manufacturers as well as in dangerous environmental in-service inspection. In this paper, we have proposed a non-contact inspection method generating the ultrasonic guided wave by laser and receiving it by an air-coupled transducer. This method can generate and receive the guided wave of a specific mode with selectivity, which makes the interpretation of received signal clearer and resultantly improves the accuracy of inspection. Also the detected signal was analyzed by using the wavelet transform and it was shown that the wavelet analysis is useful for the mode identification. The proposed method was applied to the tube of 1mm thickness and 20mm outer diameter with three different types of artificial notch defects; through-wall, inside and outside of tube. The size of defects were 2∼8mm long in the circumferential direction, with 100μm width. It was proven that all kinds of defects were detectable. Finally we have developed a practical automatic inspection system, in which the inspection result is displayed in a 2-D image.Copyright © 2004 by ASME

Automatic Non-Contact Defect Inspection of Cylindrical Shell Using a Laser-Ultrasonic Technique

Abstract: Abstract. Ultrasonic guided wave has been widely used for tube inspection. The conventional method is to use piezoelectric transducers that should be contacted to the target surface. However, in order to inspect tubes used in high temperature in-service, non-contact inspections are necessary. In this paper, we have proposed a non-contact inspection method generating the ultrasonic guided wave by laser and receiving by air-coupled transducer. This method can generate and receive the guided wave of a specific mode, which makes the interpretation of received signal clearer and resultantly improve the accuracy of inspection. Also the detected signal was analyzed by using the wavelet transform that was useful for the mode identification. The proposed method was applied to the real tube specimen with artificial defects and its inspection performance was verified. Finally we have developed a practical automatic inspection system, in which the inspection result is shown as a 2-D image.

An Ultrasonic Wheel‐Array Probe

Abstract: This paper describes the development and modeling of an ultrasonic array wheel probe scanning system. The system operates at 10 MHz using a 64 element array transducer which is 50 mm in length and located in a fluid filled wheel. The wheel is coupled to the test structure dry, or with a small amount of liquid couplant. When the wheel is rolled over the surface of the test structure a defect map (C‐Scan) is generated in real‐time. The tyre is made from a soft, durable polymer which has very little acoustic loss. Two application studies are presented; the inspection of sealant layers in an aluminum aircraft wing structure and the detection of embedded defects in a thick section carbon composite sample.