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8024250/18HT/V2-0/2020-12| SICK
O P E R A T I N G I N S T R U C T I O N S | ZIRKOR200 Ex-G
Subject to change without notice
LAYOUT AND FUNCTION
4
4.6
Pneumatic unit
The pneumatic unit is used to supply reference air and for the test gas feed of the analyzer
unit. The pneumatic unit is controlled fully automatically or manually with a ball valve
provided by the operator.
The pneumatic unit in a separate field housing can be installed next to the control unit. The
pneumatic unit is available in two versions:
●
Semi-automatic adjustment
●
Fully automatic adjustment
With fully automatic adjustment, a solenoid valve in the pneumatic unit automatically
switches between test air and test gas.
With semi-automatic adjustment, the switchover between test air and test gas is performed
by means of a ball valve.
4.7
Explosion protection description - ignition protection types
The ZIRKOR200 Ex-G system is certified for use in Ex-areas of zone 1, gas group IIC. The
control unit Z200EXG-y1 (control unit as part of the complete Z200EXG-y0 system) is
classified in temperature class T6, the analyzer unit Z200EXG-y2 (analyzer unit as part of
the complete Z200EXG-y0 system) in T3.
Ignition protection is implemented in the analyzer unit in combination of ignition protection
type flameproof enclosure Ex “d” for analyzer unit and control unit and ignition source
monitoring (see the following notes).
4.7.1
Ignition protection type “flameproof enclosure” Ex
“
d
”
For the analyzer unit and the control unit, the connection terminals for connection to the
supply voltage, supply circuits for heating and solenoid vales as well as all signal circuits in
rooms are fitted in ignition protection type “Flameproof enclosure” Ex
“
d
”
. The sensor,
which is temperature-stabilized at 800 °C, is also located inside the “flameproof enclosure”
and thus does not represent an ignition source for the environment.
With ignition protection type “flameproof enclosure” Ex
“
d
”
, the function is based on the
containment of a possible explosion inside the enclosure. This is achieved by an explosion
pressure-resistant design of the enclosure together with flameproof joints on all enclosure
openings, e.g. enclosure covers and cable inlets. Furthermore, the surface temperature is
limited below the ignition temperature of the surrounding explosive atmosphere even if an
expected fault occurs.
The threaded joints between the enclosure and cover as well as on the threaded connec-
tions are flameproof joints.
Flameproof joints must not be repaired.
The connecting surfaces must not be painted or powder coated.
It must be ensured that no explosive atmosphere is present before opening and when the
cover of an
“
Ex-d
”
area is open (e.g. during connecting or service work).
Seal all unused enclosure openings with the appropriate dummy screw fittings.
Note:
To ensure the maximum permissible surface temperature, the analyzer unit is switched
off at 810 ° C when the operating temperature is overflown and can only be heated up
by a restart. The recording of the operating temperature is done redundantly with
2 thermocouples in a sheathed thermoelement.
Switching off is performed by a protective device independent of the controller and SIL
certified for this purpose.
Operating temperature of the analyzer unit is 800 °C.
