Agilent AA Atomizer Disassembly and Re-assembly

Answer

This Information Applies To: All Agilent Atomic Absorption Spectrometry Systems (AA55, AA240, AA280) 

Issue:

How to disassemble and re-assemble the atomizer (burner, spray chamber, nebulizer)

Steps to follow:

Warning: The burner operates at high temperature. Allow sufficient cooling time before handling. There may be traces of acid on surfaces of the atomizer. Wear appropriate personal protective equipment.

1. Ensure that the flame is extinguished and the burner has cooled. Remove the burner and spray chamber (see Figure 1).

Figure 1 - Removing the burner and spray chamber

2. Prepare the following three tools: 1. Venturi Extraction tool (black), 2. Nebulizer Tool (silver) and 3. Flat-blade screwdriver (yellow handle). These tools are included with the AA when purchased. See Figure 2 below. 

Figure 2 - Venturi Extraction Tool (black, top left), Nebulizer Tool (silver, top right) and Flat-blade screwdriver (bottom) 

3. Use a flat-blade screwdriver to loosen the impact bead (glass bead) setscrew. Remove the glass bead. See Figure 3.  

Figure 3 - Loosen the glass bead setscrew and remove the glass bead

4. Loosen the nebulizer uptake adjustment (black) knob and use the nebulizer tool (silver) to loosen the capillary retaining nut (rotate anticlockwise). See Figure 4. 

Figure 4 - Loosening the nebulizer uptake adjustment knob (black) and the capillary retaining nut (rotate anticlockwise)

5. Remove the atomizer needle retaining ring, capillary, and spring.

6. Use the venturi extraction tool to push the remaining parts from the front. Cover the exit end of the chamber before pushing out to avoid losing parts). See Figure 5. 

Figure 5 - Using the venturi extraction tool to push remaining parts out of the spray chamber

7. Clean the removed nebulizer components. Components can be cleaned with water with a dilute detergent in an ultrasonic bath for 10 minutes. Worn or damaged O-rings (items 5,7,9) should be replaced. All required O-rings are available as a kit under Agilent part number 9910093400. For a parts breakdown, see Figure 6. 

Figure 6 - 1. Thimble 2. Locking ring 3. Clamp bush guide 4. Capillary assembly 5. O-ring 6. Spring 7. O-ring 8. Capillary guide 9. O-ring 10. Venturi

8. After cleaning, place the nozzle and capillary tube into the nebulizer, then use the venturi extraction tool to position it to the correct placement (all the way in). See Figure 7. 

Figure 7 - Installing the nozzle and capillary tube into the nebulizer

9. Place the spring, capillary, and capillary retaining ring in sequence. Use the nebulizer tool to lock the atomizing needle retaining ring. See Figure 8. 

Figure 8 - Installing the spring, capillary, and capillary retaining ring, then locking the atomizing needle retaining ring

10. Finally, lock the flow adjustment knob.

11. Before installing the impact bead, move the impact bead mount to the closest adjustment point and install the glass bead.

12. Make sure that there is a gap (~1–2 mm) between the glass bead and the venturi (nozzle) before locking the setscrew.

13. Re-assemble the drain tank to the spray chamber and refit to the burner adjuster. Refit the burner.

The maintenance of the atomizer is now complete.

Warning:   Incorrect nebulizer assembly and fitting in an atomic absorption spectrometer can create an explosion and fire hazards, which can cause serious personal injury and damage to property Check that the nebulizer is correctly assembled and is properly adjusted as described in the Operation Manual. Gas connections should be tested for leaks, and any leaks fixed before lighting the flame.

Learn how to effectively maintain AA Spectroscopy System: Guidelines for Troubleshooting and Maintenance of AA Systems; Spectroscopy Supplies