ABB EasyLine EL3000, Инструкция по эксплуатации

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EL3000
CONTINUOUS GAS ANALYZERS | OI/EL3000-EN REV. D 37
Housing purge
Housing design
Housing purging is only possible with the wall-mounted housing
(model EL3040). The purge gas connectors (⅛ NPT female
thread) are factory-installed in accordance with the order.
Note
Housing purging in combination with Fidas24 is described
separately, see
Housing purge with Fidas24
on page 37.
When is a housing purge necessary?
A housing purge is necessary when the sample gas contains
flammable, corrosive or toxic components, see
Special
conditions for the measurement of combustion gases
on
page 41.
Purge gas
DANGER
Risk of suffocation
Risk of suffocation due to leaking purge gas. Purge gas can
escape from the housing if there are any leak points.
• When using nitrogen as the purge gas, take all required
precautions against suffocation.
NOTICE
Damage to the device
If the purge gas flow is not restricted until after the purge gas
outlet, the full pressure of the purge gas will affect the
housing seals which can destroy the operator panel keypad!
• The purge gas flow must always be restricted upstream of
the purge gas inlet!
Suited purge gases
• Nitrogen for the measurement of flammable gases and
• Nitrogen or instrument air for the measurement of
corrosive or toxic gases
(Instrument air quality, based on ISO 8573-1 Class 3,
i.e. particle size max. 40 µm, oil content max. 1 mg/m
3
,
dew point max. +3° C).
Note
For Uras26, the purge gas must not contain any fractions of the
sample components!
Any sample components in the purge gas can cause false
readings.
Initial purging upon commissioning
Housing purge*
Purge gas Nitrogen
Purge gas flow Maximum 200 l/h
Purge time Approx. 1 hour
* Not for Fidas24, see for a separate description at
Housing purge with
Fidas24
on page 37.
If the purge gas flow is lower than specified, the duration of the
purging must be extended accordingly.
Housing purge during operation
Purge gas flow At the device input max. 20 l/h (constant)
Purge gas overpressure p
e
= 2 to 4 hPa
For a purge gas flow rate of 20 l/h at the device inlet, the purge
gas flow rate at the device outlet is approx. 5 to 10 l/h.
Housing purge during operation when measuring
flammable gases
The housing must be purged using nitrogen. Purge gas flow rate
1 to 20 l/h. The purge gas flow must be monitored at the purge
gas output.
Housing purge with Fidas24
In the Fidas24 gas analyzer, the housing purge is provided in
such a way that a part (approx. 600 to 700 l/h) of the instrument
air is conducted continuously through the housing as purge air.
Thus it is guaranteed that no ignitable gas mixture can form
within the housing in case of a leak in the combustion gas path.
The housing purge is always active when pressurized air is on,
that is also when the instrument air valve is closed.