ELTRA CS-800, Manual

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be too low oxygen pressure in the analyzer, especially at moments of high oxygen
consumption, like when burning samples or purging the furnace.
3.2.11
77B
Heavy item is placed on the plastic tube of the oxygen supply
Years of experience have shown that not only bent plastic tubes can be a reason
for insufficient oxygen supply, but also that a foot of the analyzer’s cabinet was
placed on the tube, squeezing it and restricting the oxygen flow. In one case, the
customer prolonged the tube using a fitting with too small inner diameter causing
the same effect like bending or squeezing the tube.
3.2.12
78B
Twisted plastic tube inside the analyzer
It happened that, when fixing cap nuts of the black plastic tube inside the analyzer
but also at the furnace outlet, the tube was turned with the nut and twisted, badly
restricting the oxygen flow.
3.2.13
79B
Oxygen supply is interchanged with the compressed air supply
In case of reported bad combustion, we experienced in a number of cases, that the
tubes of oxygen and compressed air supplies were interchanged. Compressed air
in the induction furnace will provide combustion but a bad one, because of only
20% of oxygen existing in the air. Therefore the peaks are low and long, consisting
of more than one peak, looking like mountains.
CAUTION: Oxygen in the pneumatic cylinder can lead to its explosion.
3.2.14
80B
Blocked dust filter cartridge
The dust filter cartridge is on the front panel so that contamination is visible for the
operator. In the gas flow circuit, this dust cartridge is connected after the metal filter
and its following glass tube with magnesium perchlorate, so that the carrier gas
passing thru the cartridge is already filtered. The cartridge is used as an additional
safety to ensure that the carrier gas passing thru the IR cell and the flow sensor,
are as clean as possible. Therefore it takes long until the cartridge is contaminated,
so that its ranking is almost at the end of the list.
3.2.15
81B
Blocked fittings
This case is extremely unlikely to happen in case of an induction furnace analyzer,
because the analyzed materials in question are inorganic materials like metals and
ceramics, so that they don’t create fumes, volatiles and moisture. Even cement
analysis is not as critical as organics analysis. Anyway, this information is included
in this list in order to have it complete.
In case of analysis of materials causing major contamination, the fittings of the IR
cells can be blocked so that they have to be cleaned.
Also fittings elsewhere can be blocked, like the fittings for plastic tubes on the
reagent glass-tube holders.
3.2.16
82B
Blocked flow sensor assembly
If the flow sensor is blocked, it should normally be replaced.
For those who may decide to clean them - please read the description about
cleaning.
3.2.17
83B
Electronic problem
The flow controller consists of 3 components:
1. The flow sensor
2. The board HF-42 (The lower half of the board only).
3. The proportional valve V6.
The electronic devices involved in the flow regulation are the board HF-42 and the
flow sensor. The only influence of the PC and of the microcontroller on the flow, is
the start/stop of the flow in case of gas saving mode.