3 | Explosion protection
20
D-LX 201/721
Components that hold these housings together (e.g. screws and cable glands) are
safety-relevant. For sufficient safety of cable glands in the Ex d space at least five
turns of the thread must mesh perfectly. Safety-relevant components must only be re-
placed with approved spare parts. Only these spare parts have been demonstrated to
be able to withstand the strains they are subjected to.
Ignition-proof gaps must only be repaired according to the design specifications of the
manufacturer. Repairs according to the values of Table 1 or 2 of EN 60079-1 are not
permissible.
WARNING
Risk of explosion due to the operation of a flame monitor with a damaged Ex d
housing!
The Ex d housing contains sources of ignition. The operation of a damaged or
modified Ex d housing in a potentially explosive atmosphere can lead to an explosion.
Therefore:
In order not to change the gap dimensions in a way that makes them impermissible:
▶ Do not make any retroactive changes to the housing
▶ Have damaged housings or damaged ignition-proof gap surfaces replaced by a
certified expert company.
▶ Only use original screws for the closures
▶ Only use permissible cable glands so as to guarantee the explosion protection.
With the cables used, observe the cable diameter clamping area permissible for
the cable gland.
▶ Only use cables that are suitable for use in the hazardous area (installation ac-
cording to EN 60079-14).
3.6.2 Ignition protection type "Ex n" (gas)
This ignition protection type is used for
device group and category II 3 G (zone 2)
. The
operating materials covered by this type are not capable of igniting a potentially ex-
plosive atmosphere in normal operation or defined abnormal operating conditions.
Non-sparking operating materials "Ex nA"
It is assumed that an operating material used during normal operation will behave like
an operating material with ignition protection type
Increased safety
Ex e
, and will not
have any ignition sources as a result of hot surfaces and electrically or mechanically
generated sparks.
The flame monitor housing corresponds to ignition protection type "Ex nA".
The contacts of sparking operating materials are protected in a suitable
manner; "Ex nC"
There are encapsulated relays inside the flame monitor housing. These correspond to
ignition protection type "Ex nC". The cable gland corresponds to an ignition protection
type that can be combined with "Ex n_".
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