PerkinElmer aanalyst 200 User Manual page 79

AAnalyst 200 User's Guide
How the Burner System Works
The basic instrument includes a burner system for flame sampling operation. A system block
diagram is shown in the next figure. As previously mentioned, the heat produced by the burner
converts the sample into free atoms that can absorb the light from the source lamp for the
element(s).
A sample solution is aspirated through the nebulizer and sprayed as a fine aerosol mist into the
burner chamber. Here, the sample mist is thoroughly mixed with the fuel and either air or nitrous
oxide gases. Fuel gas enters the chamber through the fuel inlet hose while the oxidant enters
through the nebulizer side-arm and the AUX oxidant inlet.
To prevent incomplete sample atomization, a plastic flow spoiler is placed inside the chamber
directly in front of the nebulizer. The nebulizer utilizes a ceramic, one-piece, impact-bead
structure which improves nebulization efficiency. Larger sample droplets not carried around the
flow spoiler by the gas flow are forced by the spoiler to the bottom of the chamber. This, in turn,
allows only the finer sample droplets to be carried into the chamber. The larger droplets are
removed through the drain.
Once the sample mist is thoroughly mixed in the chamber, it is carried to the burner head. Once
there, the flame causes dislocation and atomization.
The gas control system monitors and controls fuel and oxidant flows. Burner operation, including
flame ignition, flame shutoff and gas flow settings, is controlled through the instrument touch
screen (AAnalyst 200).
The next figure shows a "block diagram" of how the AAnalyst burner system flows, from the gas
supplies, to the gas box, to the burner hardware itself and out to the drain vessel.
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