EXPO MiniPurge D801/ET User manual

ML488 | v19 13-January-2022
D801-ET MiniPurge®
Manual
ML488
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.
Expo Technologies reserves the right to replace any component, with one of the equivalent functionality.

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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 ........................................................................................................5
Section 4: Description and Principle of Operation ............................................................................6
Section 5: Main Components ...............................................................................................................7
Air Supply Filter ........................................................................................................................................................................7
Logic Air Supply Regulator ..................................................................................................................................................7
Purge Flow Regulator ............................................................................................................................................................7
CLAPS Regulator ......................................................................................................................................................................7
Low Pressure Sensor .............................................................................................................................................................7
Purge Flow Sensor ..................................................................................................................................................................8
CLAPS Sensor ............................................................................................................................................................................8
Electronic Purge Timer ..........................................................................................................................................................8
EPPS (Electro-Pneumatic Power Supply) .......................................................................................................................8
Alarm Only Circuit (/AO) ........................................................................................................................................................8
Power Interlock Switch .........................................................................................................................................................8
Alarm / Pressurized Switch .................................................................................................................................................9
System Purging Switch (Optional) ...................................................................................................................................9
Intermediate Switch ...............................................................................................................................................................9
Visual Indicators ......................................................................................................................................................................9
Relief Valve Unit ......................................................................................................................................................................9
/PA Terminal Box .....................................................................................................................................................................9
Section 6: Installation of the System .............................................................................................. 10
Relief Valve Unit ...................................................................................................................................................................10
Air Supply Quality .................................................................................................................................................................10
Pipe Work .................................................................................................................................................................................11
Multiple Enclosures ..............................................................................................................................................................11
Provision and Installation of Alarm Devices ..............................................................................................................11
Power Supplies and their Isolation ...............................................................................................................................11
Power Interlock Switch ......................................................................................................................................................11
Section 7: Commissioning ................................................................................................................. 13
Commissioning the System ..............................................................................................................................................13
Normal Operation .................................................................................................................................................................14
Section 8: Maintenance of the System ............................................................................................ 15
General maintenance ..........................................................................................................................................................15
Additional maintenance checks ......................................................................................................................................15
Re-calibration of the Relief Valve Unit .......................................................................................................................15
Re-calibration of the Pressure Sensors .......................................................................................................................16
Section 9: Fault Finding .................................................................................................................... 17
General Information ............................................................................................................................................................17
System purges correctly but trips and auto re-purges at the end of the purge time. .............................17
Relief Valve opens (continuously or intermittently) .............................................................................................18
System enters purging but purge indication does not occur .............................................................................18
System begins purging but cycles fail to complete ...............................................................................................18
Section 10: Recommended Spares List ........................................................................................... 19
Section 11: Glossary .......................................................................................................................... 19
Section 12: Drawings and Diagrams ................................................................................................ 20
Section 13: Certificates ..................................................................................................................... 20

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Section 1: System Specification
7 X LC / ss / ET / OV / PA / PC
Size
7 = MiniPurge®
Purge flow rate:
7000 - 14000 NI/min
Approval / Certification
Sira 01ATEX1295X
2813 II 2(2) GD
Ex [pxb] ia IIC T5 Gb
Ex [pxb] ia IIIC T100ºC Db
Tamb -20ºC to +55ºC
IECEx SIR07.0027X
Ex [pxb] ia IIC T5 Gb
Ex [pxb] ia IIIC T100ºC Db
Tamb -20ºC to +55ºC
PA = Power and Alarm Switches.
Integral /PA Terminal Box
OV = Purge Outlet Valve is pneumatically
operated
Timing Method
ET = Electronic Timer
MiniPurge®Housing
ss = Stainless Steel 316L
Pressurization Method
LC = Leakage Compensation
ATEX Certificate:
IECEx Certificate:
PC = Pressurized Control. Automatic
leakage compensation (CLAPS)
For limitations and conditions of use refer to the applicable certificates.
CCC 2020312304000830
Ex [px] ia IIC T5 Gb
Ex [pD] iaD 21 T100ºC
Tamb -20ºC to +55ºC
CCC Certificate:
EAC Certificate:
ЕАЭС RU С-GB.АЖ58.В.00906/20
1Ex [px] ia IIC T5 Gb
Ex [px] ia IIIC T100°C Db
(-20°C ≤ Tamb ≤ +55°C)
TÜV 12.1462X
Ex [pxb] ia IIC T5 Gb
Ex [pxb] ia IIIC T100ºC Db
Tamb -20ºC to +55ºC
TÜV INMETRO Certificate:

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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).
Purge Flow Capacity 14000 NI/min max.
Enclosure Material: Stainless Steel 316L.
Mounting Method: Wall mounting lugs & spacers. 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: 4.2 to 8 barg (61 to 116 psi).
Logic Regulator and Gauge: Fitted and set to 2.5 barg (36 psi).
CLAPS Regulator & Guage: Set to system requirements.
Process Connections: Purge supply and outlet to motor - 2” NPT female.
Minimum supply line 50 mm (2”) I.D Pipe.
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).
Power Interlock Switch: DPNO switch, contact ratings 250 Vac 4 Amps (AC-15) / 24V DC 4A,
Ex d IIC T6 Gb / Ex tb IIIC T80ºC Db.
Alarm Switch: SPCO switch, contact ratings 250 Vac 4 Amps (AC-15) / 24V DC 4A,
Ex d IIC T6 Gb / Ex tb IIIC T80ºC Db.
Intermediate Switch: SPCO switch, contact ratings 250 Vac 4 Amps (AC-15) / 24V DC 4A,
Ex d IIC T6 Gb / Ex tb IIIC T80ºC Db.
System Purging Switch (Optional): SPCO switch, contact ratings 250 Vac 4 Amps (AC-15) / 24V DC 4A,
Ex d IIC T6 Gb / Ex tb IIIC T80ºC Db.
High Pressure Switch (Optional): SPCO switch, contact ratings 250 Vac 4 Amps (AC-15) / 24V DC 4A,
Ex d IIC T6 Gb / Ex tb IIIC T80ºC Db.
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: 6.0 mbarg.
Default Setting: 4.0 mbarg.
Tolerance: -0, +10%.
High Pressure Sensor: Minimum: 20.0 mbarg.
Maximum: 35.0 mbarg.
Default Settings: 25.0 mbarg.
Tolerance -0, +10%.
Note: There must be a 1.5 mbarg difference between the minimum pressure and intermediate sensors.

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Relief Valve Unit and Purge Outlet Valve with integral spark arrestor
Purge Flow Sensor: Set at 6.4 mbarg (Tolerance: -0, +10%).
CLAPS Sensor: Minimum: 10.0 mbarg.
Maximum:15.0 mbarg.
Default Setting: 10.0 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).
Default Setting 99 minutes.
Weight: 70 kg (154.3 lb).
Type: RLV200/ss/FS
Bore: Purge Outlet Valve Ø 200 mm, Relief Valve Ø 200 mm.
Relief Valve Lift-Off Pressure: Minimum: 20.0 mbarg (+0, -20%).
Maximum: 35.0 mbarg.
Default: 30 mbarg.
Flow Rate: Factory set to: 7000 to 14000 NI/min.
Material: Housing: Stainless steel 316L.
Gasket: Neoprene.
Spark arrestor: Stainless steel mesh.
Mounting Method: Rectangular cut-out and fixing holes as per drawing.
Weight: 23 kg (50.7 lb)
Orifice: Special orifice plate may be required.

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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 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 piping 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
pressure 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.
On completion of an uninterrupted purge cycle of the required length, the system will indicate purge complete.
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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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.
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/or Zone 2(22) - Categories 2 and 3 respectively.
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.
Indicator Colour Status
Alarm / Pressurized Green Pressurized and in leakage compensation mode
Purging Black No longer in purge mode
Materials of Construction
Stainless Steel Aluminium Acrylic
Mild (Carbon) Steel Nylon Silicone
Brass Polyurethane Neoprene
ABS Polycarbonate Polyester (glass filled)

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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/or Zone 2 (22) 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.

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Pressure characteristics during purge and pressurization of a pressurised enclosure using a MiniPurge®
system that incorporates a CLAPS system:
Section 5: Main Components
Air Supply Filter
The unit is provided with a 40 μm liquid / dust filter element as a precaution. The user of the MiniPurge®system
must ensure that air supply is to the quality stated in ‘Air Supply Quality' paragraph found in the Installation
section.
Logic Air Supply Regulator
This device provides the system with a stable logic pressure supply for consistent operation. The pressure level
is factory set to 2.5 barg (36 psig) and can be verified by means of the integral pressure gauge. It should only
be adjusted if the gauge indicates that the regulated pressure is incorrect.
Purge Flow Regulator
This regulator controls the volume of purge air flowing through the system. It can be adjusted as required to
give the desired purge air flow during commissioning.
CLAPS Regulator
This is the regulator that controls the leakage compensation air flow into the enclosure after the purging is
complete. It either increases or decreases the air flow into the enclosure as appropriate to maintain a stable
running pressure. The CLAPS Regulator must be set at the time of commissioning.
Low Pressure Sensor
The pressure inside the Pressurized Enclosure is monitored continuously by these devices. When the pressure
is correct i.e. above the minimum pressure specified for safe operation, it provides a “Pressurized” output signal
that can be seen by the operator e.g. displayed on a local Red/”Green” visual indicator. The sensor is factory
calibrated to operate on a falling pressure at or above the minimum specified pressure.
Intermediate Pressure
Sensor Pressure
Power Interlock switch
Alarm &Trip
Purge Time Machinery Start Normal Operation
CLAPS Regulator
Pressure
Intermediate switch contacts
open. Intermediate sensor
sends falling pressure signal
Fault Condition - loss of pressure
outside of CLAPS regulation
Minimum Pressure
Sensor Pressure
Purging Pressure
Minimum pressure switch contacts
open. Minimum pressure sensor sends
a low pressure signal.
Alarm indicator shows red (alarm only)
Alarm indicator shows red and power
is disconnected (Alarm and Trip)
Minimum
pressure switch
Intermediate
pressure switch
Power Interlock switch
Alarm Only
Contacts
Active
Inactive