Buzz-o-sonic is being used by a refractories company, RHI Canada, to reduce the production costs of some of their product lines. Costs savings are significant when the slower, more expensive, traditional cold crushing strength test is replaced by the state-of-the art impulse excitation technique as implemented by Buzz-o-sonic. The sonic velocity or speed of sound is measured on several types of brick by using Buzz-o-sonic to measure the longitudinal resonant frequencies.

Note: sonic velocity = 2 x length x longitudinal frequency

The results were published in Ceramic Industry magazine (November 2009)

The sonic velocity vs cold crushing strength (ccs) of some refractory shapes are shown below in figure 1.
E vs T

Fig. 1. sonic velocity vs cold crushing strength (ccs)


Because of the good correlation, it was possible to identify the weakest brick: those with a sonic velocity of 1800 m/s or lower. Since September 2008, one line of brick is now being tested using the Buzz-o-sonic testing system rather than cold crushing strength; though one in five samples are still crushed. In addition, when a result below the sonic velocity limit is observed then the standard destructive CCS test is done before releasing or recycling product. Nevertheless, the reduction in CCS testing was significant at ~25% in 2008 on some brands.