Needle capacitance probe

Figure 24 An example of a capacitance probe, (a) High-temperature two-needle capacitance probe of Wiesendorf et al. (1999) (With permission of American Society of Mechanical Engineers), (b) Output signals from a 12 mW (Chalmers) and a 250 MW (Gardanne) CFB boiler obtained with the probe shown in (a). (Johnsson et al., 1999.) With permission of DECHEMA e.v.

Figure 8. Section through a needle capacitance probe to show the basis of construction.

FIGURE 3-17 Capacitance probes needle-type (left) plate-type (right). 

A capacitance probe was developed in our work (Brereton and Grace, 1992) based upon a DISA capacitative pressure transducer system. It effectively measures the instantaneous suspension density in an approximately 5 mm cubic zone surrounding the exposed needle. The capacitance probe was used to study radial variations and the form of solids flow structures present in the developing region of a cold circulating bed. Sand particles with a mean diameter... 

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