Latest revision as of 11:30, 25 January 2021

Abstract

Ultrasonic inspection is a standard method to assess the integrity of large-diameter oil pipelines. However, similar methods applied to natural-gas pipelines present a considerably greater challenge; gas is a poor coupling agent for the probing ultrasonic signals between the transducer and the pipe wall. Natural gas exhibits a very low specific acoustic impedance (300 Rayls for methane at atmospheric pressure) compared to oil (1.5 MRayls and higher). Consequently, large ultrasonic-signal transmission losses occur at the transducer/gas and pipe-wall/gas interfaces. To circumvent this obstacle, past exploratory developments included the use of a liquid-filled wheel [1], electromagnetic-acoustic-transducer (EMAT) [2], and liquid-slug technologies [3]. While prototypes of high-speed, in-line inspection systems employing such principles do exist, all exhibit serious operational shortcomings that prevent widespread commercial exploitation.

Original document

The different versions of the original document can be found in:

• https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=2142&context=qnde

• http://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=2142&context=qnde,

https://lib.dr.iastate.edu/qnde/1995/allcontent/120,

https://link.springer.com/chapter/10.1007/978-1-4615-1987-4_120,

https://core.ac.uk/display/38894817,

https://trid.trb.org/view/465425,

https://academic.microsoft.com/#/detail/1484501200

• http://www.springerlink.com/index/pdf/10.1007/978-1-4615-1987-4_120,

http://dx.doi.org/10.1007/978-1-4615-1987-4_120