ELTRA CS-580A, Руководство по эксплуатации

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Function description
37
The analyzer is operated with pure oxygen. A purity of 99.5% is sufficient. It is
normally available in steel bottles. CO2 and H2O impurities in the oxygen are
trapped in the trap (8). The upper half of the trap is filled with CO2 absorber and
the lower half with moisture absorber.
Magnesium perchlorate (anhydrone) acts as a H2O absorber.
Sodium hydroxide acts as CO2 absorber, preferably with an indicator, so that the
degree of saturation can be seen from the coloration.
The oxygen inlet pressure should be 2 to 4 bar, which is then regulated inside the
analyzer to 1.5bar, as shown on the pressure gauge (4). Any pressure fluctuation
of the external oxygen supply has no influence on the accuracy of the
measurements.
A pressure switch (4) becomes conductive at around 1 bar (15 psi). This
information is passed to the software which energizes the valve (5) and starts the
gas pump (22) as long as the pressure is higher than 1 bar. This ensures that the
pump runs only when sufficient pressure of oxygen is available, so that no air
enters the gas flow system, if there is no input oxygen pressure.
With the help of the adjustable restrictor (6) the inlet flow is set at a level of at least
200 l/h. The flow rate is shown on the lower flow meter (7) on the front panel. This
flow rate enters the furnace. During analysis when the furnace is closed, the inlet
flow rate is split. One part enters the furnace top to exit the lance over the crucible.
This flow is shown on the middle flow meter (11). The rest of the oxygen flow
enters the furnace at the low end. The ratio of the two flows can be adjusted with
the restrictors (10) and (13).See chapter
”Adjusting gas flow” .
The flow at the outlet of the furnace is created by a pump (22) at the end of the gas
flow system, which sucks a flow of 180L/h out of the furnace.
A tube connects the furnace outlet with the moisture trap (14). The gases that
come out of the furnace normally contain some moisture. This particularly happens
when analyzing coal samples. The dried gases pass thru the dust filter (15) and
then enter the Infrared cells which are accommodated in the cell module (19),
where the measurements of CO2 and SO2 take place.
The gas flow through the cells is shown on the upper flow meter (20) on the front
side of the analyzer. The displayed value must be at constant 180 l/h. The
attenuator (21) makes the pulsing flow of the pump (22) smooth. The flask (23) is a
silencer for the pump exhaust.