Edwards EDS 300

3. ATEX cercaon
DANGER: INTERNAL EXPLOSION
The EDS dry pump is designed to pump gas and/or vapours. Ensure that the pump
temperatures are sucient to prevent condensaon forming which may otherwise lead
to corrosion and loss of explosion protecon. The use of seal purges and correct warm-up
and shut-down procedures are necessary to prevent the formaon of condensaon. If in
any doubt, please consult Edwards.
Sha-seal purge must be maintained in order to ensure long term reliability of sha-seals
and the zoning/protecon concept.
If blockages of the exhaust are possible, exhaust pressure should be monitored,
otherwise excessive back-pressure can occur, leading to high temperatures and risk of
explosion.
The EDS ATEX Category 3 dry pump uses the
protecon strategy of construconal safety for
internal atmospheres, and sases the requirements for ATEX Category 3.
Construconal safety relies on there being no ignion sources inside the pump. EDS dry
pumps are manufactured and tested to show that running clearances are maintained in the
pump during extremes of normal operaon and at trip points of pump safety instruments.
For Category 3 inside pumps, ignion hazards are prevented from occurring in normal
operaon. When using construconal safety as the protecon concept ensure that no
process deposits are formed inside the pump which could potenally create an ignion
source. This can be achieved either by process control or by the use of solvent ush. In such
systems the solvent ush operaon is safety crical and suitable safeguards must be put in
place to ensure that solvent ow is maintained to the prescribed regime. The gearbox of the
EDS pump is classied one zone lower than the pumping chamber; the high-integrity seal in
combinaon with seal purge ensures zone separaon.
The EDS is capable of pumping a potenally explosive atmosphere that is likely to occur
occasionally in normal operaon and therefore sases the essenal requirements
idened in Annex II of the ATEX Direcve 2014/34/EU for Category 3 equipment.
3.1 Classicaon and marking of the pump
The pump is marked as follows:
II 3/-G Ex h IIC T3 Gc
5 °C < Ta < 40 °C
(internal atmospheres only)
Modifying the supplied pump, voids the CE and ATEX Declaraon of Conformity.
Table 1
Key to the Symbols
ATEX logo
h The code leer “h” is valid for all non-electrical devices.
IIC Explosion group
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A41802880_C - ATEX cercaon