Burners and Aspirators

FIGURE 9-5. Jarrell-Ash burner for flame emission (turbulent flow). [Courtesy Jarrell-Ash Division, Fisher Scientific Co.] 

Other laminar flow burners are available. Most of them premix the fuel and oxidant and have a separate nebulizer to break the liquid sample into small droplets. A drain, or chamber, is provided so the larger droplets do not enter the flame but are collected and removed from the system. This 

Corrosion Proof Mixing Penton Plastic Chamber 

FIGURE 9-7 Perkin-Elmer laminar flow burner. [Courtesy the Perkin-Elmer Corp.] 

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Flame excitation methods, coupled with simple read-out devices, provided high sensitivity and high reliability for the determination of the alkali metals in simple liquid systems. Further development of burners and aspirators, higher flame temperatures, better spectral isolation using gratings or prisms, and more sensitive detection and read-out devices has increased the list of elements that can be detected by flame excitation to between 50 and 60. 

The limitations of the Meeker burner to act as an excitation source soon led to the development of other burners and aspirators, or burner-aspiration combinations. One of the most successful was that designed by the Beckman Corporation. Their burner-aspirator is illustrated in Figure 9-4 and is known as a total-consumption burner since all the sample that enters the capillary tube enters the flame, regardless of droplet size. This burner-aspirator introduces the oxidant and fuel in separate parts of the burner, mixing them at the top exit of the burner. The liquid sample enters the flame... 

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