Basic HTML Version
Appendix B
5/20/2009
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follow the step by step instruction shown on the screen. If
the procedure is followed correctly and to its conclusion, the
Maintenance Schedule Information for that tube will be
reset. You can return to the Service Menu at almost any
point by pressing “End.”
17.4.2.2.For the CHN Analysis there are instructions for:
17.4.2.2.1. Tube Packing Information
17.4.2.2.2. Helium Scrubber Replacement
17.4.2.2.3. Oxygen Scrubber Replacement
17.4.2.2.4. Carbon Dioxide Trap Replacement
17.4.2.2.5. Water Trap Replacement
17.4.2.2.6. Combustion Tube Replacement
17.4.2.2.7. Reduction Tube Replacement
17.4.2.2.8. Combustion & Reduction Tubes Replacement at
the same time
17.4.3.
Combustion Tube
17.4.3.1.Hold the tube vertically with the short end from the
indentation up. Roll up a piece of platinum gauze so that it
will fit snugly into the combustion tube. Slide the gauze plug
into the tube and up against the indentation.
17.4.3.2.Add a small plug of quartz wool. (Quartz wool may be
muffled for one hour at 850 °C to remove any residual
carbon).
17.4.3.3.Add 1½” of silver tungstate/magnesium oxide on
chromosorb. Gently tap the tube to prevent the reagent from
channeling.
17.4.3.4.Add a small plug of quartz wool.
17.4.3.5.Add 2” of silver oxide/silver tungstate on Chromosorb tap
the tube and add another small plug of quartz wool.
17.4.3.6.Slide a rolled-up piece of silver gauze into the tube and pack
against the quartz wool. Make sure that there is no less than
½” of space between the end of the tube and the silver gauze
since the silver gauze will conduct heat and damage the o-
ring on the end connector.
17.4.3.7.The amount of each reagent used can be varied to suit the
type of materials to be analyzed. For example, if
predominantly fluoridated compounds are run
proportionately more silver tungstate/magnesium oxide
should be packed into the tube.
17.4.3.8.There is rarely such a thing as a “too tightly” packed
combustion tube. Loosely packed combustion tubes can
cause non-linearity.