| The most commonly encountered type of
patternators are variations on a straight-forward linear array of collecting
tubes. The tube arrays are typically fitted with a shutter to control liquid
access to the collecting tube apertures. The array is placed within the
spray, most commonly along an axis passing through the centerline of the
atomizer. The sprayed liquid is collected for a specified time and the
volume of liquid collected in each tube is measured. The measurement step
can be performed manually, or automated by means of video-capture, level
sensors or pressure transducers.
Variations on the linear tube patternator include:
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integrating tube patternator
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radial array tube patternator
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tray-and-tube patternator
All tube patternators have the disadvantage of a spatial
resolution fixed by the aperture and spacing of the individual collector
elements. The effective resolution is degraded when tube patternators are employed on sprays of
highly uneven distribution, as the regions of attenuated spray density may
collect an amount of liquid insufficient to be reliably measured. The fixed
aperture of the collector elements also demands that low-flowrate sprays
require much greater sampling times than high-flowrate sprays. Additionally,
the large spray diameters typical of industrial-scale atomizers require
either very wide arrays, or the stepping of a narrow array across the spray
envelope.
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