EXPO MiniPurge D825/ET User manual

ML550 | v6 & ML384 | v3 09-Jan-20
D825/ET MiniPurge®
Manual
ML550 & ML384
Important Note:
It is essential for safety that the installer and user of the Expo system follow these
instructions.
Please refer to the standard for principles and definition.
These instructions apply only to the pressurizing system. it is the responsibility of the
manufacturer of the pressurized enclosure to provide instructions for the enclosure.

ML550 | v6 i
Section 1: System Specification................................................................................................1
MiniPurge® Control Unit Data...................................................................................................2
Relief Valve Unit and Purge Outlet Valve with integral spark arrestor......................................3
Section 2: Quick User Guide......................................................................................................4
Installation ................................................................................................................................4
Operation of the System...........................................................................................................4
Section 3: Application Suitability ..............................................................................................6
Section 4: Description and Principle of Operation ..................................................................7
Section 5: Main Components.....................................................................................................8
Air Supply Filter / Regulator......................................................................................................8
Logic Air Supply Regulator .......................................................................................................8
Minimum Pressure Sensor .......................................................................................................8
Purge Flow Sensor ...................................................................................................................8
Intermediate Sensor .................................................................................................................8
Electronic Purge Timer .............................................................................................................8
Purge Complete Valve..............................................................................................................8
OR Gate ...................................................................................................................................9
Alarm Only Circuit (/AO) ...........................................................................................................9
Power Interlock Output .............................................................................................................9
Alarm / Pressurized Output ......................................................................................................9
Intermediate Pressure Output ..................................................................................................9
Purge Valve ..............................................................................................................................9
CLAPS Sensor .........................................................................................................................9
CLAPS Regulator .....................................................................................................................9
Visual Indicators .....................................................................................................................10
Relief Valve Unit .....................................................................................................................10
Explosionproof Terminal Box..................................................................................................10
Section 6: Installation of the System.......................................................................................11
Relief Valve Unit .....................................................................................................................11
Air Supply Quality ...................................................................................................................11
Pipe Work ...............................................................................................................................12
Multiple Enclosures ................................................................................................................12
Provision and Installation of Alarm Devices ...........................................................................12
Power Supplies and their Isolation .........................................................................................12
Power Interlock Switch ...........................................................................................................12
Section 7: Commissioning .......................................................................................................14
Commissioning the System ....................................................................................................14
Normal Operation ...................................................................................................................15
Section 8: Maintenance of the System....................................................................................16
General maintenance .............................................................................................................16
Maintenance of Electronic Timer ............................................................................................16
Re-calibration of the Relief Valve Unit....................................................................................16
Re-calibration of the Pressure Sensors..................................................................................17
Section 9: Fault Finding............................................................................................................18
General Information................................................................................................................18
System purges correctly but trips and auto re-purges at the end of the purge time...............18
Relief Valve opens (continuously or intermittently).................................................................19
System enters purging but purge indication does not occur...................................................19
Section 10: Recommended Spares List..................................................................................20
Section 11: Glossary.................................................................................................................20
Section 12: Drawings and Diagrams .......................................................................................20
Section 13: FM ML384 Manual .................................................................................................21
Appendix A: Certifications ......................................................................................................28

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ML550 | v6
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Section 1: System Specification
Size
5 = MiniPurge®
Purge flow rate:
2000 to 6000 NI/min
Approval / Certification
ATEX Certificate:
Sira 01ATEX1295X
0518 II 2(2) GD
Ex [pxb] ia IIC T5 Gb
Ex [pxb] ia IIIC T100°C Db
Tamb -20ºC to +55ºC
IECEx Certificate:
IECEx SIR07.0027X
Ex [pxb] ia IIC T5 Gb
Ex [pxb] ia IIIC T100°C Db
Tamb -20ºC to +55ºC
TÜV INMETRO Certificate:
TÜV 12.1462X
Ex [pxb] ia IIC T5 Gb
Ex [pxb] ia IIIC T100ºC Db
Tamb -20ºC to +55ºC
FM Certificate:
FM 1X8A4.AE (USA&Canada)
Class I Div 1 Groups A B C & D
Type X Pressurization
Refer to Section 13 of this manual
for FM specific manual ML384
For limitations and conditions of use
refer to the applicable certificates in
Appendix A of this
manual.
PO = Pneumatic outputs, connected to actuators
on explosionproof terminal box
PC = Pressurized Control. Automatic
leakage compensation (CLAPS)
OV = Purge Outlet Valve is
pneumatically operated.
Timing Method
ET = Electronic Timer
MiniPurge® Housing
ss = Stainless Steel 316L
Pressurization Method
LC = Leakage Compensation
5X POET /ss /
LC / OV / PC /

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MiniPurge® Control Unit Data
Action on Pressure Failure: Alarm and Trip (isolate power to pressurized enclosure), user
adjustable Alarm Only.
Type of Operation: Automatic leakage compensation using the Closed Loop Automatic
Pressurization System (CLAPS System).
Leakage Compensation
Capacity
1000 NI/min initial maximum pressurized enclosure leakage.
1500 NI/min maximum as leakage increases.
Enclosure Material: Stainless Steel 316L.
Mounting Method: Wall mounting straps. Fixing holes as per drawing.
Temperature Limits: -20oC to +55oC
Compressed Air Supply: Clean, dry, oil free air or inert gas. Refer to Air Supply Quality section
in Installation of the System.
Supply Pressure: 5 to 16 barg (73 to 232 psi).
Main Regulator: Set at 5 barg, 40 μm automatic drain supply inlet filter.
Logic Regulator and Gauge: Fitted and set to 2.3 barg (33 psi).
Process Connections: Purge supply and outlet to pressurized enclosure 1” NPT female.
Minimum supply line 25 mm (1”) ID tube.
Reference points & signals 1/8” NPT female.
Visual Indicators: Alarm (Red ) / Pressurized (Green ).
System Purging: 4 LEDs that flash sequentially to indicate elapsed
time (black when not purging).
Terminal Box: Aluminium, Explosionproof Class I and Class II, Division I group B, C,
D, E, F, and G. Flameproof Ex d Zone 1 Gas Group IIC.
Power Interlock Switch: DPNO 120 Vac 1A.
Alarm/Pressurized Switch: SPCO 120 Vac 6A / 250 Vac 3A.
Pressure Switch: SPCO 120 Vac 6A / 250 Vac 3A.
Minimum Pressure Sensor: Minimum: 0.5 mbarg.
Maximum: 5.0 mbarg.
Default Setting: 1.5 mbarg.
Tolerance -0, +0.7 mbarg.
Intermediate Sensor: Minimum: 2.0 mbarg.
Maximum: 10 mbarg.
Default Setting: 5.0 mbarg.
Tolerance: -0, +10%
Note: There must be a 1.5 mbarg difference between the minimum pressure and intermediate sensors.
Purge Flow Sensor: Set at 6.4 mbarg (Tolerance: -0, +10%).
CLAPS Sensor: Minimum: 5.0 mbarg.
Maximum:15 mbarg.
Default Setting: 10 mbarg.
Tolerance: -0, +10%
Note: there must be a 2.5 mbarg difference between the intermediate and CLAPS sensor calibration point.
For example: Minimum pressure = 5 mbarg, intermediate pressure = 6.5 mbarg, CLAPS sensor = 9 mbarg.
Purge Time: User selectable, in 1 minute intervals, up to 99 minutes (tolerance -0,
+3 seconds).

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ML550 | v6
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Relief Valve Unit and Purge Outlet Valve with integral spark arrestor
Default Setting 99 minutes.
Weight: 27 kg (60lb).
Type: RLV104/ss/FS.
Bore: Purge Outlet Valve Ø 104 mm, Relief Valve Ø 75 mm.
Relief Valve Lift-Off Pressure: Minimum: 20 mbarg.
Maximum: 50 mbarg.
Default: 30 mbarg (+0, -20%).
Flow Rate: Range: 2000, 3000, 4000, 5000, or 6000 NI/min.
Default: 2000 NI/min.
Material: Housing: Stainless steel 316L.
Gasket: Silicone foam.
Spark arrestor: Stainless steel mesh.
Mounting Method: Rectangular cut-out and fixing holes as per drawing.
Weight: 7 kg (15.4 lb)

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Section 2: Quick User Guide
Installation
The MiniPurge® System must be installed by a competent engineer, in accordance with relevant standards, such
as IEC / EN 60079-14, NEC500 and any local codes or practice.
• Mount the purge system in accordance with the hook-up drawing.
• Ensure the system is installed according to the full instructions in the “Installation of the System” section of
this manual.
• All pipings must be clean and free of dirt, condensation and debris prior to connection to the purge system or
pressurized enclosure.
• It is strongly recommended that a local isolation valve is installed on the air supply upstream of the purge
system.
Note: Most faults are due to restricted air supply, inadequate supply pipe work or drop in air supply pres-
sure during the purge process.
Operation of the System
Once the system is installed correctly, turn on the air supply. Refer to Commissioning section.
The purge system commences the purge cycle:
• The purge air will enter the enclosure.
• The pressurized enclosure will obtain a positive pressure.
• The Purge Outlet Valve will open within the Relief Valve Unit.
• The air will then exit the Relief Valve Unit housing via the spark arrestor.
Open the Purge Flow Restrictor Valve until the air flow reaches the required rate; the system will initiate the timed
purge cycle. Start a stopwatch when the purging indicator flashes yellow.
Indicator Colour Status
Alarm / Pressurized Red Low pressure alarm (enclosure pressure too low)
Purging Black Purge flow too low or not in purge mode
Indicator Colour Status
Alarm / Pressurized Green Pressurized (minimum enclosure pressure achieved)
Purging Black Purge flow too low
Indicator Colour Status
Alarm / Pressurized Green Pressurized
Purging Sequential flashing
Yellow
Purge flow rate above minimum

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On completion of an uninterrupted purge cycle of the required length, the system will indicate purge
complete. Stop the stopwatch when the purging indicator stops flashing.
Check stopwatch timing to verify that the actual purge time is equal to or greater than the required purge time.
Note: The recorded purge time must never be less than the required purge time.
The system is now operating correctly in leakage compensation mode.
If the system has not performed as expected, check the installation thoroughly and ensure it has been carried
out according to the instructions.
If an obvious problem has not been highlighted and corrected, follow the procedures in the Fault Finding section.
If all checks have been carried out and the system still does not perform as expected, contact your local
distributor or Expo Technologies.
Indicator Colour Status
Alarm / Pressurized Green Pressurized and in leakage compensation mode
Purging Black No longer in purge mode

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Section 3: Application Suitability
MiniPurge® systems are certified for use in hazardous locations, where the hazardous location is non-mining
(above ground) and the hazard is caused by flammable gasses, vapours or dust. Depending on the model the
systems may be used in IECEx and ATEX Zone 1(21) and Zone 2(22) - Categories 2 and 3 respectively, and
Class I/II/III Division 1 and Division 2.
MiniPurge® systems may be used for hazards of any gas group. Apparatus associated with the MiniPurge®
system, such as intrinsically safe signalling circuits and flameproof enclosures containing switching devices may
be limited in their gas group. The certification documentation supplied with any such devices must be checked
to ensure their suitability.
This system is primarily designed for use with compressed air. Where other inert compressed gasses are used
(Nitrogen, for example) the user must take suitable precautions so that the build up of the inert gas does not
present a hazard to health. Consult the Control of Substances Hazardous to Health (COSHH) data sheet for the
gas used. Where a risk of asphyxiation exists, a warning label must be fitted to the pressurized enclosure.
The following materials are used in the construction of MiniPurge® systems. If substances that will adversely
affect any of these materials are present in the surrounding environment, please consult Expo Technologies for
further guidance.
Materials of Construction
Stainless Steel Aluminium Acrylic
Mild (Carbon) Steel Nylon Silicone
Brass Polyurethane Neoprene
ABS Polycarbonate Polyester (glass filled)

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ML550 | v6
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Section 4: Description and Principle of Operation
The MiniPurge® system is pneumatic in operation, with electrical interfaces.
Purge and pressurization is a method of protection used in Zone 1 (21) and Zone 2 (22), and Division 1 and
Division 2 hazardous locations, to ensure that the interior of an enclosure is free of flammable gas. Addition of a
MiniPurge® system allows the electrical equipment within the enclosure to be used safely in a hazardous
location.
The principle of purge and pressurization is as follows:
• Clean compressed air or inert gas is drawn from a non-hazardous location.
• The interior of the pressurized enclosure is flushed to remove any hazardous gas or dust.
• This is introduced into the pressurized enclosure to keep the internal pressure at least 0.5 mbarg above the
external pressure.
• Whilst pressurized, flammable gas cannot enter the enclosure from the environment.
Prior to switching on the power to the electrical equipment, the enclosure must be purged to remove any
flammable gas that might have entered the enclosure before pressurization. Purging is the process of removal
contaminated air and replacement with air (or inert gas) known to be free from flammable gas. The duration of
this purge process is normally ascertained by performing a purge test.
At the end of the purge cycle the system automatically switches to leakage compensation mode.The Purge
Outlet Valve is closed and the airflow is reduced but remains high enough to compensate for the leakage of air
from the enclosure whilst maintaining the minimum over pressure state.
In the event of pressure failure within the pressurized enclosure the system will raise an alarm in the form of visual
indicators and a volt free contact depending on the specification of the system. The default action on loss of
pressurization is alarm and automatic disconnect of power (A&T - Alarm and Trip). This can be changed by the
customer to Alarm Only (/AO), please refer to section titled Main Components.
The MiniPurge® system incorporates a Closed Loop Automatic Pressurization System (CLAPS). This allows the
system to detect a rise or fall of the enclosure’s internal pressure and adjust the leakage compensation rate
accordingly. Pressure variations are more likely during sudden start up of large rotating electrical machines but
can also be caused by changes in running temperature. This system has been specifically designed to maintain
a stable internal pressure within the enclosure.