Pepperl+Fuchs 6000 SERIES Installation And Operation Manual page 30

6000 Series Purge/Pressurization System
• Enclosure power – This is (red) when the
enclosure power is off, and (green) when
enclosure power is on. The enclosure power can
be on only after a successful purge and a safe
pressure is achieved. The bypass option allows
power to remain on if safe pressure is lost.
• Rapid Exchange – The rapid exchange or purging
®
flow rate turns on (blue) when the flow rate is
measuring proper flow.
• System bypass – This turns on (yellow) when the
system bypass is active. This should be used only
when the area around the enclosure is known to
be safe.
• Alarm fault – The (red) LED blinks when any alarm
input is detected and is solid when there is an
internal system fault.
Pneumatic manifold with I.S. solenoid
• Manifold with I.S. solenoid valve: The manifold
system is mounted on the 6000 control unit
providing a needle valve to set enclosure pressure
and an I.S. solenoid valve that is used for purging
(Rapid Exchange). Power for the I.S. solenoid
valve is provided by the EPCU and is galvanically
isolated. Regulated instrument-grade air or
nitrogen is required.
The 6000 series unit can be ordered without the manifold
so that customers can use their own method or valves
for purging and pressurization. If a third-party electronic
valve is used, the valve must be certified and installed in
accordance with the hazardous location where the unit is
operating. The use of the 6000 series manifold unit allows
easy and correct installation of the system.
Requirements for purging/pressurization
Certifications allow the 6000 series to be used on
enclosures in gas, dust, or both gas and dust hazardous
atmospheres. Gas atmospheres require the purging of
the enclosure. Dust atmospheres require the physical
removal of all the dust that collects inside. Both gas and
dust atmospheres require the following: 1) removing the
dust, 2) sealing the enclosure, and then 3) purging the
enclosure.
After these sequences, the pressure within the enclosure
is above the minimum level. The equipment within the
enclosure can then be energized.
Purge timing
When using the 6000 series in a gas or gas and dust
location, the time for purging an enclosure can be based
either on a known purge rate and time (fixed purge
time), or based on the flow rate being measured from
the vent (dynamic purge time). Both methods base the
time on the flow measurement at the vent, and complete
the process in steps. The EPCU will take the readings
from the vent and use the appropriate reading (listed
below) as the usable flow rate. For example, if the flow
26
rate measurement from the EPV-6000 vent is 7 SCFM
(198 l/m), the EPCU will use 5 SCFM (141 l/m) as the
flow rate for evaluation. The flow rate measurement steps
and corresponding enclosure pressures are as follows:
EPV-6000-XX-01, 02
5 SCFM @ 1.5" wc, (141 l/min @ 3.7 mbar)
12 SCFM @ 2.0" wc, (340 l/min @ 5.0 mbar)
20 SCFM @ 2.7" wc, (565 l/min @ 6.7 mbar)
30 SCFM @ 4.1" wc, (850 l/min @ 10.2 mbar)
EPV-6000-XX-03, 04
5 SCFM @ 2.1" wc, (141 l/min @ 5.2 mbar)
12 SCFM @ 2.6" wc, (340 l/min @ 6.5 mbar)
20 SCFM @ 4.1" wc, (565 l/min @ 10.2 mbar)
30 SCFM @ 5.3" wc, (850 l/min @ 13.2 mbar)
EPV-6000-XX-05, 06
5 SCFM @ 1.5" wc, (141 l/min @ 4.5 mbar)
12 SCFM @ 2.9" wc, (340 l/min @ 7.3 mbar)
The following parameters must be entered for
the purge time:
Note
• Enclosure volume
• Number of exchanges.
Minimum purge time is 2 min
Note
Fixed purge time
If the purge time must be held to a specific time, then this
time is based on the known enclosure volume, number
of volume exchanges, and flow rate through the vent.
If the flow rate is below the required minimum, then the
purging cycle will reset and will not start until the flow
rate is above the selected rate. This setup does not
allow purge flow to go below the value required and will
not recalculate the time for purging if it goes above the
required purge rate. This measurement method is the
same type as was used in our previous system, the 4000
series. The actual time is calculated by the EPCU.
Dynamic purge time
Dynamic purge time allows the purge time to be updated
based on the purge flow through the vent. This method is
not dependent on a constant flow from the protective gas
source. It bases the purge time on the measured flow and
not a set flow. This is very useful when the protective gas
supply pressure varies throughout the purging cycle or
when it may vary from one installation to another.
The purge time will be based on the measurement of
the vent and evaluation of this measurement from the
EPCU. This allows recalculation of the time based on
this measurement. During the dynamic purge time, the
user interface will display the purge time in a percentage
starting with 0% and ending with 100% (purge time
complete).
I/O Manual