thuba PS 830, Manual

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Manual BVS 19 ATEX E 080 X 11
Edition March 2020 thuba Ltd., CH-4002 Basel
Copyright Switzerland
d) Installer can also remove covers or
doors of internal housings if they pro-
vide adequate vent diameters alterna-
tively.
e) If the topics above are not applicable, a
separate piping must be added to the
internal compartment. The purge medi-
um flow through the compartment must
be high enough to make sure that the air
in the compartment is exchanged at
least 10 times higher.
For instance:
2.3 Determination of pre-purging period
If its not sure, at power up, that the atmosphere
inside of the enclosure and the appropriate pipes
is below 25% of the lower explosive limit (LEL)
(IEC 60079-14 chapter 13.4), a prepurging of the
pressurized enclosure is necessary.
The pre purging of the housing is prohibited, by
an Ex pD system (pressurized enclosure in zone
22).
2.4 Purge medium requirements
1 The purging medium must not be derived
from hazardous area, it must be contamina-
tion free (dry, free of oil and dust)
2 The temperature of the purge medium
should not exceed 40°C.
3 If another purge medium than air is used, it
is important to regard the minimum oxygen
content of the ambient. Maybe it is neces-
sary to install a exhaust pipe from the PS
830 to out-of-door.
PS840
Ex pzc housing
nozzles for air
distribution
internal compartment
valve