Safety devices
Explosion protection
Prevention of arcing
:
The inner chamber does not contain any built-in electrical equipment. All of the unit's metallic
components are included in the electric safeguards / earth bonding.
The homogeneous materials used in the inner chamber and the design features of the
mechanical moving parts
rule out the possibility
of
arcing as a result of mechanical friction
.
The
blower design
ensures that ignition cannot be caused by arcing when the ventilation system
switches on.
Sealing:
The inner enclosure is
welded steam-tight
in order to prevent condensation forming in the
thermal insulation. The inner door casing is made of a single piece. The door is sealed tight by
thermally aged silicone rubber seal. The door bearings are adjustable to guarantee the sealing
effect on a permanent basis.
Ventilation:
When the unit is switched on, the
entire internal airspace is rinsed with fresh air before the
heating system can be switched on
. This ensures that no dangerous, potentially explosive
atmosphere can build up in the heating system, between the fresh-air intakes and the entry to the
inner chamber.
The unit's
ventilation system
is monitored constantly by flow monitors.
The heating is
deactivated immediately if there is a fault in the ventilation system
.
The above-mentioned rinsing procedure takes place every time the door to the unit is closed, e.g.
after loading, and the function of the ventilation monitoring system is checked automatically
("Fault" alarm signal).
The
ventilation fail-safety device
prevents a potentially explosive atmosphere in the inner
chamber from entering the ventilation system and making contact with hot surfaces in the event
of a power failure.
Electric control system:
A switchbox in the base of the unit accommodates the electric system. Fitting the switchbox into
the unit (IP 54) and the additional sealing of the control panel ensures that no dangerous vapors
can penetrate the switchbox while the unit is in operation.
Figure 2/3:
Side view of the control panel
S e a l
C o v e r
D o o r
Interlock circuits
which could come into contact with dangerous vapor/air mixtures in the event
of a fault, have been realized in accordance with the requirements for the
"intrinsically safe"
type of protection
(EEx i (a) II C).
3
UNIT SPECIFICATION
16/25
50 043 136
