Control Box (Ex P) - BARTEC BENKE DPA-4.5 Operating Manual

2.4.2 Control box (Ex p)

Figure 2.2: Control box
(front view)
Figure 2.1: Control box key switch
The control box (Ex p) contains operating equipment without its
own ignition protection type and therefore contains potential
ignition sources.
The control box is pressurized for explosion protection (Ex p).
To prevent potentially explosive atmospheres from developing,
overpressure is created with the aid of instrument air in the interior
of the control box. The overpressure is monitored by a pressure
monitor.
Even after the power supply is switched off, components on the
inside can still have electrical charges or high temperatures which
represent potential ignition sources.
The key switch is used to turn the pressure monitor of the control
box on and off.
To switch on the pressure monitor on:
•
Close the door of the control box.
•
Turn the key counterclockwise up to its stop (see Figure 2.1).
Pull the key out.
The control box pressure monitor is switched on. The box is
protected against explosions.
If the pressure inside the control box drops below a specified
limit value, the pressure monitor switches off the power supply
for the analyzer.
NOTE
For further information on pressure monitoring,
please refer to the manual on the
APEX pressurization system.
•
Make sure that only responsible persons have access to the
key.
December 2013
Distillation Process Analyzer DPA-4.5
Safety
27