ELTRA CS-580A, Руководство по эксплуатации

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Maintenance
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Before the reagent tubes are fitted, the O-rings and the inner ends of the tubes
should be lubricated with high vacuum silicon grease.
4.2.2 Filling quantities
As different samples can contain different amounts of moisture, it is hard to give a
precise number of analyses that can be made before the content of the reagent
tubes should be replaced.
A regular check of the reagents is essential to secure a failure free operation of the
analyzer.
The moisture stems from the combustion and has two sources. One source is the
water content of the sample. By drying the sample in a furnace at about 80 °C, the
moisture content can be reduced. The sample is laid in a fairly flat bowl and should
be spread as thin as possible. The drying process takes some hours.
The second source is the hydrogen content of the sample itself, available in
various hydrogen compounds.
The following chemicals are used
Magnesium perchlorate (Anhydrone) as moisture absorber
Sodium hydroxide as CO2 absorber
The reagent tubes have to be replaced when they are saturated. If the absorber
particles do not move when tapping on the glass, it is a sign that the magnesium
perchlorate is saturated. It is essential to change the absorber before it is
completely solid. The sodium hydroxide changes its color after being saturated (it
turns to light grey).
It is not possible to dry the magnesium perchlorate and to use it again, as it is
chemically modified after reacting with the moisture. It should be pointed out that
magnesium perchlorate is a very strong oxidative material.
A clear sign of total saturation is when the absorber's particles do not move freely
after tapping at the glass tube. Normally, the moisture absorbers should be
checked after 30 to 40 analyses
The grade of the absorber saturation is at its maximum at the gas entrance of the
tube and it becomes gradually less toward the glass tube outlet. Therefore, once
the upper half only of the magnesium perchlorate can be replaced and next time
the complete content of the glass tube.
Please refer to chapter
front panel illustration to identify the glass tubes on the
analyzer.
Before filling the reagents into the glass tubes, their lower end has to be stuffed
using glass wool. One should pay attention that the layer of glass wool should be
pressed only as strongly as necessary, otherwise the flow of gas could be choked.
Under no conditions the amount of glass wool should be less than that given in the
following schematics, as fine particles of magnesium perchlorate could penetrate
the glass wool and accumulate at the bottom of the tube blocking the fitting and
building deposits in tubes and in the Infrared cell paths.
At both ends of the glass tube, you should leave sufficient space for the gas
connections to be fitted. The free spaces at the tube ends serve as sealing areas.
They must be cleaned and greased after filling.
Both, the O-rings as well as the sealing areas of the tube are to be greased with
high vacuum silicon grease. This enables easy reassembling as well as later
removing. In addition, greasing improves the sealing of the tubes to the O-rings.
Only the upper end of the right hand glass tube (moisture trap) and the
corresponding O-ring should not be greased.
Make sure that the O-rings are completely sealed around the glass tubes!