BEKA BA307E, Руководство пользователя

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Appendix 1
Dust certification
A1.0 ATEX dust certification
In addition to ATEX certification permitting
installation in explosive gas atmospheres which is
described in the main section of this instruction
manual, all BA307E, BA327E, BA308E and
BA328E indicators have ATEX certification
permitting installation in combustible dust
atmospheres.
This appendix describes ATEX installations in
explosive dust atmospheres conforming with
EN 60079-14 Electrical installations design,
selection and erection. When designing systems
for installation outside the UK the local Code of
Practice should be consulted.
The indicator’s dust input and output safety
parameters are identical to gas parameters, so all
the electrical circuits shown in the main section of
this manual may also be used for dust
applications.
A1.1 Zones, and Maximum Surface
Temperature
The BA307E, BA327E, BA308E and the BA328E
have been ATEX certified as Group II, Category
1D Ex ia IIIC T80ºC Da IP20 apparatus, Ta -40 to
70°C.
When connected to a suitable system the
indicators may be installed in:
Zone 20 explosive atmosphere in the form of
a cloud of combustible dust in air is
continuously present, or for long
periods or frequently.
Zone 21 explosive atmosphere in the form of
a cloud of combustible dust in air is
likely to occur occasionally in normal
operation.
Zone 22 explosive atmosphere in the form of
a cloud of combustible dust in air is
not likely to occur in normal
operation, but if it does occur, will
only persist for a short period.
Be used with dust in subdivisions:
IIIA combustible flyings
IIIB non-conductive dust
IIIC conductive dust
(For use with IIIC conductive dusts
special conditions for safe use apply
– see section A1.4)
Having a Minimum Ignition Temperature of:
Dust cloud 120°C
Dust layer on indicator 155
°
C
up to 5mm thick
Dust layer on indicator Refer to
over 5mm thick. EN 60079-14
At an ambient temperature between -40 and +70°C
A1.3 Maintenance
ENSURE PLANT SAFETY BEFORE
STARTING MAINTENANCE
Live maintenance is permitted on
intrinsically safe equipment installed in a
hazardous area, but only certified test
equipment should be used.
All models have IP66 front of panel protection and
a gasket is provided to seal the joint between the
instrument and the mounting panel thus preventing
dust ingress from the outside of the mounting
panel. The rear of the instruments is not sealed,
but ATEX dust certification is dependent on the
internal conformal coating of the instrument, so
dust ingress is acceptable except for use in IIIC
conductive dusts – see A1.4. However, it is good
practice to minimise the amount of dust
accumulating on the rear of the instrument.
A1.4 Special conditions for use in IIIC dusts
The ATEX certificate for the loop powered
indicators has an ‘X’ suffix indicating that special
conditions for safe use are required for installion in
IIIC dust atmospheres, the certificate states:
‘For use in Group IIIC conductive gas
atmospheres, the indicator shall be
mounted such that the instrument
terminals have at least IP6X protection.’
To prevent the indicator terminals becoming
contaminated by conductive dust:
The indicator must be installed in a panel,
cubicle or enclosure providing a minimum of
IP6X protection.
The gasket supplied to seal the joint
between the indicator and the mounting
panel must be used, and the 144 x 72mm
BA308E and BA328E indicators must be
secured with four panel mounting clamps.
Note: These special installation conditions only
apply for indicators exposed to IIIC conductive dust
atmospheres.