Authors: A. Sadri, I. Gordon, A. Rampersad
Abstract
A new and innovative non-destructive testing (NDT) technique based on the stress wave propagation principles has been developed for condition monitoring of refractory lining in blast furnace hearths. In addition to the refractory thickness measurements and flaw detection, the Acousto ultrasonic-echo (AU-E) technique is capable of determining refractory and skull thickness measurements from the shell, weather the cooling staves are present or the shell is shower cooled. The signals are generated by a broadband mechanical shock generator, capable of causing echoes from various layers of blast furnace lining. Particular mathematical filters and finite element analysis are used to select the appropriate signal generator tools, signal bandwidth, signal frequency, receiving transducers, and appropriate signal processing tools to accurately determine the thickness of remaining lining. Each signal is averaged and analyzed in both time and frequency domain.
In this paper, we introduce the principals of the AU-E technique. In addition, we demonstrate a series of case studies conducted over the past ten (10) years for determining the hearth refractory lining, accretion, and taphole thicknesses. Also we present a series of case studies, demonstrating the success of the AU-E to determine the condition of bonding between the shell and the refractory and locating delamination between the refractory layers.
