| Under the most benign of conditions, atomizers
experience wear which will degrade the spray performance over time. Wear
generally most affects the nozzle orifice, internal flow passages and the
internal whirl vanes or disks. As the nozzle wears, the flow rate increases,
the spray pattern becomes irregular and the dropsize spectrum produced
becomes coarser and broader. High temperature operation, corrosive and
erosive environments, abrasive and corrosive liquids will all accelerate the
performance degradation. For critical applications, the atomizer's
performance must be assessed across its wear life in order to determine the
point at which the performance changes sufficiently to compromise the
process.
Using our
spray dynamics analysis
capabilities, spray research, inc. is
able to fully document the incremental effects of wear on an atomizer's
performance. Our
coordinate measurement system allows performance degradation to
be correlated with field-measurable dimensional changes. Wear analysis
can be performed with successive customer-supplied samples of nozzles used
in the actual process. A more rigorous approach is to follow a single
atomizer sample through its wear life. The atomizer is returned to the
process after each evaluation interval. Alternatively, the atomizer sample
can be subjected to accelerated wear by simulating the process conditions
using spray research's selection of
environmental chambers and fluid simulants. |