ELTRA CS-800, Manual

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In case of a fault however, a control of the flow rate is no longer possible and the
gas flow fluctuates. This can be caused, for example, by an excessive obstruction
of the gas flow system or by a faulty component that needs to be replaced.
See the next pages of this chapter and chapter Gas flow controller adjustment and
jumper settings
Mostly, the problem lies in the saturation of the dust trap or of the chemicals.
In case the flow becomes lower and the regulating valve voltage goes higher
during combustion, it is obvious that the flow regulator is working. Therefore the
problem must be a restricted oxygen supply. When the accelerators start burning
they take a lot of oxygen, so that the pressure in the furnace goes down, and as a
result for this the flow may also go down.
List of fault reasons in order of probability:
(Details to the above points)
• Blocked metal dust filter
• Blocked chemicals
• Blocked paper filters
• Blocked lance hole over the crucible.
• Blocked hole of the ceramic heat shield
• Blocked furnace outlet
• Too low oxygen pressure
• The outlet tap of the oxygen regulator is not properly open
• Faulty oxygen regulator
• Contaminated or corroded solenoid valve
• Bent plastic tube of oxygen supply
• A heavy item is placed on the plastic tube of the oxygen supply
• Twisted plastic tube inside the analyzer
• The oxygen supply is interchanged with the compressed air supply
• Blocked dust filter cartridge
• Blocked fittings
• Blocked flow sensor assembly
• Electronic problem
3.2.1
67B
Blocked metal dust filter
Clean the metal dust filter according to the operation manual.
Caution: Even if the filter may be brushed and cleaned in ultrasonic cleaner,
someday will not be able to be cleaned any more. The filter doesn't last forever.
Check by removing the filter with the dust filter housing. See chapter: High carbon
results are erratic
Don’t remove the filter from its housing.
Turn the filter housing upside down and try to blow air through the small whole
(about 16mm diameter) of the filter housing.
If you feel a remarkable restriction, replace it by a new one. With a new filter the air
should pass practically free without any restriction.
3.2.2
68B
Blocked chemicals
The grains of magnesium perchlorate as well as of sodium hydroxide have to move
when knocking on their glass tube. If they are cloggy, they are completely depleted
and they have to be replaced. When the glass tube is turned upside down, the
grains should fall off. If a screw driver is needed to stab the grains free, the
chemicals had to be replaced much earlier.