Mini-X-Purge Size 1 Manual ML 442 - Expo Technologies

Mini-X-Purge � Size 1 Manual 

ML 442 

Contents 

1. Specification Sheet – Mini-X-Purge � Systems 

2. Application Suitability 

3. Description and Principle of Operation 

4. Installation of the System 

5. Commissioning 

6. Maintenance of the System 

7. Fault Finding 

8. Approval Documents 

9. Glossary 

ML 442 Issue 5C SP5115 09/11/12 © 

Page 1 of 22

1. Specification Sheet – Mini-X-Purge � Systems 

Model No. (Example): 07 1 XLC / ss / PO / WM (Note: Not all codes are applicable) 

Purge System Type 

07 = MiniPurge 

Size 

1 = Sub MiniPurge 

Purge flow rate 225 Nl /min, 8 scfm 

Approval / Certification 

X = 

Europe 

EN60079-0, EN60079-2, EN 61241-0, EN61241-4 

Sira 01ATEX1295X 

0518 II 2 (2) G D 

Ex [px] IIC T6 Gb 

Ex [p] IIIC T85ºC Db 

Tamb -20ºC +55ºC 

IEC 

IEC60079-0, IEC60079-2, IEC61241-0, IEC61241-4 

IECEx SIR 07.0027X 



Tamb -20ºC +55ºC 

USA / Canada NFPA 496 

FM 1X8A4AE 

Class I Div 1 Groups A, B, C & D 

UL E190061 

Class I Div 1 Groups A, B, C & D 

BRAZIL INMETRO/TUV TÜV 12.1462X 



-20ºC ≤ Ta ≤ +55ºC 

For limitations and conditions of use refer to the 

applicable certificate at the back of this manual. 

Options as Required 

AO = Alarm Only 

MO = Manual Override 

MK = MIU Mounting Kit (PO systems only) 

WM = Wall Mounting Bars 

Power & Alarm (Signals) 

PO = Pneumatic Output 

“Power” : On Purge Complete = 30 psi / 0.2 MPa / 2 bar Signal 

“Alarm” : Loss of Pressure = No signal 

”Pressurized” = 30 psi / 0.2 MPa / 2 bar Signal 

PA = Power and Alarm Terminal Box Ex e IIC T6 

“Power” ; 250 Vac 4 Amp AC15 2PNO – Ex d IIC T6 

“Alarm” : 250 Vac 4 Amp AC15 SPCO – Ex d IIC T6 

(European and IEC Systems Only) 

IS = Intrinsically Safe, Ex i & Ex i circuit 

“Power” : used with others’ Ex i equipment 

“Alarm” : Relay / Barrier 

MiniPurge � Housing 

ss = 316L Stainless Steel 

Neoprene “Top” Mount Gasket 

pm = Panel Mount (Side/Front Mount) 316L 

Stainless Steel 

Presurization Method 

CF = Continuous Flow 

LC = Leakage Compensation 

Supply Pressure: Must be regulated at inlet 

Minimum 60 psi / 0.4 MPa / 4 bar 

Maximum 115 psi / 0.8 MPa / 8 bar 

Air Quality: Compressed air / Nitrogen to instrument quality 

Ambient Temperature: -20ºC to + 55ºC 

Leakage Compensation: Variable up to 2 scfm / 60 Nl/min to compensate for leakage of enclosure 

Purge Timer: Stepped adjustable between 1 minute and 30 minutes 

Flow & Pressure Sensors: CF: One sensor for both 

“Low Pressure and Flow”: 1” WC / 250 Pa (2.5 mbar) 

LC: “Low Pressure Sensor” 0.2” WC / 50 Pa (0.5 mbar) 

“Flow Sensor” 1.13” WC/ 280 Pa / (2.8 mbar) 

Relief Valve: System: CF LC 

Model No: RLV25/ss RLV25/FS/ss 

Opening Pressure: 4” WC / 1 kPa (10 mbar) 4” WC / 1 kPa (10 mbar) 

Purge Flow Rate: N/A (see Spark Arrestor) 8 scfm / 225 Nl/min 

Material: 316L Stainless Steel, Spark Arrestor: Stainless Steel mesh, Gasket: Neoprene 

Spark Arrestor Unit Model No: SAU25 

(CF systems only) Purge / Dilution Flow Rate: Between 0.4 & 8 scfm / 10 & 225 Nl/min 

7 user selectable orifice plates 

Material: Stainless Steal 

Bulkhead Pipe Fittings: Air Supply: 1/2” NPT 

Output: 1/2” NPT 

Signal: 1/8” NPT 

Visual Indicators: CF: Alarm / Pressurized (Red / Green) 

Purge Complete (Red / Green) 

LC: Alarm / Pressurized (Red / Green) 

Purge Complete (Black / Amber) 

Action on “Loss of Pressure”: 

CF: Action on “Loss of Pressure” = “Alarm & Trip”. Option /AO specifies an “Alarm Only” kit. 

LC: Action on “Loss of Pressure” = “Alarm & Trip” or “Alarm Only”. LC Model is user selectable. 


Page 2 of 22

2. Application Suitability 

MiniPurge � Systems are certified for use in Hazardous Areas, where the Hazardous Area is 

non-mining (i.e. above ground) and the hazard is caused by flammable gasses, vapours or dust. 

Depending on the model, the systems may be used in IECEx, ATEX Zone 1(21) - Category 2 

and NEC 500 Class I, Div 1. 

MiniPurge � systems may be used for hazards of any gas group. However, 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 designed for use primarily 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 for further guidance. 

Materials of construction: 

� Stainless Steel � Aluminium � Acrylic 

� Mild (carbon) Steel � Nylon � Silicone Rubber 

� Brass � Polyurethane � Neoprene 

3. Description and Principle of Operation 

All Expo Technologies MiniPurge � pressurization systems provide: 

a) a method of pressurizing a Pressurized Enclosure (PE) while at the same time compensating 

for any leakage, together with 

b) a method of purging the enclosure, before power is applied, to remove any flammable gas 

that may have entered the enclosure while it was not pressurized, 

c) visual indication of the MiniPurge � system status, and 

d) an output to provide remote indication or control. 

The MiniPurge � system comprises a number of component units. The units required depend on 

the type of system selected. These are summarised in Table 1. The general description and 

function of each is as follows: 

3.1 Control Unit (CU) 

The Control Unit (CU) is the heart of the system. It contains a pneumatic logic circuit specially 

designed and built to control the functions required for purge and pressurization. For all 

systems this includes air filtration, pressure and purge flow measurement, purge timing, and 

local visual indication of Pressurized/Alarm and flow sensed. It also provides the outputs for 

power and remote alarm control corresponding to the output type selected. 


Page 3 of 22

3.2 Relief Valve (RLV) 

The Relief Valve unit is fitted to the PE to provide a means of limiting the 

maximum pressure experienced by the PE during operation. The RLV 

model number has a suffix giving the diameter of the valve aperture in 

millimetres e.g. RLV25 (= 25mm bore). The RLV also incorporates a 

Spark Arrestor to prevent sparks being ejected from the PE into the 

classified area. 

In Leakage Compensation systems, the RLV is combined with the flow 

measurement mechanism. 

Figure 1. LC Relief Valve 

3.3 Calibrated Outlet Orifice/Spark Arrestor (SAU) 

Continuous Flow systems incorporate the SAU25. This unit has 

a range of interchangeable calibrated orifice plates, which are 

used to measure the flow through the PE. 

3.4 The Methods of Pressurizing 

Figure 2 Spark Arrestor Type SAU25 

a) CF - Continuous Flow 

A Continuous Flow (CF) of protective gas is passed through the PE. Initially this flow is verified 

and performs the purging phase of the operation. When the purging phase is completed – i.e. 

the purge time has elapsed- the same flow of protective gas maintains the pressurization of the 

enclosure. This flow may be required to dilute an internal source of hazardous gas release. 

Figure 3 Continuous Flow Circuit Diagram 


Page 4 of 22

) LC - Leakage Compensation 

Initially a high flow of protective gas is passed through the enclosure. This flow is verified and 

performs the purging phase of the operation. When the purging phase is completed – i.e. the 

purge time has elapsed - the flow of protective gas is provided via an adjustable valve so that it 

just compensates for any leakage from the PE in addition to maintaining its pressurization. 

If leakage is less than 5 l/min then the LCV will be awkward to set. You will find that the RLV 

spring will cycle open and closed. If this happens contact our service department for advice. 

Figure 4 Leakage Compensation Circuit Diagram 

3.5 Type of Output 

The functions of the outputs are power control and alarm/pressurized indication. Power control 

provides a signal to switch the power to the PE. Alarm output provides a passive signal to 

indicate remotely when the enclosure is not pressurized and an active signal when pressurized. 

a) PO- Pneumatic Output 

The power control and pressurized outputs are pneumatic signals, which may be used to 

operate other devices to provide power switching or alarm indication. The lack of any output 

signal indicates incomplete purge and alarm. In many instances these outputs may be 

connected to the Expo range of MiniPurge � Interface Unit s (MIU). 

Figure 6 Pneumatic Output Option 

Figure 5 Typical MiniPurge Interface Unit 

type (MIU/dA) 


Page 5 of 22

) IS - Intrinsically Safe Output 

The power control and alarm outputs are volt free contacts which form part of an Intrinsically 

Safe (IS) circuit which then provides power control or alarm outputs in a safe (unclassified) 

area. These contacts must only be connected to IS circuits as the switch contacts are in the 

hazardous area. In many instances these outputs may be connected to the Expo range of 

MiniPurge � Interface Units (MIU). 

Figure 7. Intrinsically Safe (IS) Option 

c) PA - Power and Alarm 

By integral Ex d flameproof switches, terminated in Ex e junction box in accordance with 

European standards. 

Figure 8. Ex de Power and Alarm (PA) Option 


Page 6 of 22

4. Installation of the System 

This MiniPurge � is designed for use under normal industrial conditions of ambient temperature, 

humidity and vibration. Please consult Expo before installing this equipment in conditions that 

may cause stresses beyond normal industrial conditions. 

The MiniPurge � system shall be installed in accordance with relevant standards, such as IEC / 

EN 60079-14, NEC 500, NFPA 496 and any local codes of practice that are in force. 

There are up to three components for the MiniPurge � system, dependant upon the system type: 

System type Control Unit (CU) 

Relief Valve 

(RLV) 

Spark Arrestor 

Unit 

Leakage Compensation YES YES Integral to RLV 

Continuous Flow YES YES YES (SAU25) 

Table 1 System Components 

4.1 Control Unit (CU) 

The MiniPurge � system should be installed either directly on or close to the PE. See mounting 

details. Generally the most convenient arrangement is to install the CU on the top of the PE. 

Must be mounted vertically as shown in MiniPurge � Configuration XBR-7TD0-003. The CU can 

be mounted on the side of the PE using the rear mounting fixings. The piped connections to the 

PE should be made using metallic tube through suitable bulkhead connections. The CU can be 

remote mounted using the wall mounting bars (/WM option), and should be installed as close as 

possible to the PE. It should be installed so that the system indicators and certification labels 

may be readily observed. 

4.2 Relief Valve (RLV) and Spark Arrestor Unit (SAU) 

To achieve efficient purging the points where air enters and exits the PE should normally be at 

opposite ends of the PE. These items must be mounted vertically. The RLV or SAU are 

recommended to be situated at the bottom, or on the side of the enclosure at the bottom, when 

the CU is top mounted on the enclosure, thus achieving top to bottom purging. The purge air 

may be piped within the PE to ensure purging of potential dead air spots. 

It is important that the interior and exterior of the Spark Arrestor is kept clean and debris is not 

allowed to accumulate which might affect the calibration of the device. In particular the exterior 

of the Spark Arrestor should not be painted or blocked off in any way. 

4.3 Connections to Protective Gas Supply 

The MiniPurge� system should be connected to a protective gas supply, which is suitable for 

purging and pressurization. The air supply to the filtration system must be clean, nonflammable, 

from a non-hazardous area and free from water and oil to BS ISO 8573-1: 2001 

Class 2.2.1 or relevant local standards. This is typically referred to as “Instrument Air Quality”. 

Solid Particles: 0.5µm < particle size � 1µm, maximum 1000 particles/m3 

Humidity: -40ºC* pressure dewpoint 

Oil content: �0.01mg/m3 concentration total oil 

* For applications where Tamb � 0ºC, the air supply should be Class 2.1.1, with Humidity: -70ºC 

pressure dewpoint. 

Although equipment will operate with lower air quality, the operational life of the system will be 

adversely affected. The equipment that is being protected may also suffer from poor air quality. 


Page 7 of 22

The minimum air supply pressure should be 4 bar/ 60 psig / 4MPa. It is important that the 

compressed air / inert gas supply is capable of delivering the quantity required for purging at 

normal purge flow rate, maintaining the minimum pressure. This means ensuring adequate size 

of pipe and airline accessories. Over 80% of commissioning problems reported to Expo are due 

to inadequate sized piping or air supply. Although the MiniPurge � unit includes a filter, the 

compressed air / inert gas supply should have a dedicated local air pressure regulator. 

4.4 Purge Air from CU to PE 

When the CU is directly top mounted onto the PE, no connection will normally be necessary, as 

the purge air will discharge into the PE directly. When the CU is not top mounted, or where 

internal air distribution is necessary a connection should be made from the purge air outlet on 

the CU (normally ½” NPT Female), via pipe pressure rated at least to the supply pressure, to 

the PE. This should be kept as short as possible and should be adequately sized to ensure that 

the full purge flow can be delivered. 

4.5 CU to Enclosure Pressure Monitor 

When the CU is directly top mounted onto the PE, no connection will normally be necessary, as 

the enclosure pressure monitor point will sense directly inside the PE. Only if the CU is not 

directly mounted or if there are fans, which may create localised low-pressure areas within the 

PE, it is necessary to pipe this connection. The connection is made to the enclosure pressure 

sensor fitting (normally 1/8” NPT Female) on the CU. There is virtually no flow in this circuit, so 

small bore tube may be used. Expo recommends 4mm O/D nylon tube. Make sure that all 

connections are free of leaks. 

4.6 CU to Flow Sensor 

In Continuous Flow (CF) systems, a Differential Pressure Sensor is combined with the Minimum 

Pressure Sensor and measures the "DP HI (High) / Enclosure Pressure" within the PE and the 

pressure in the monitoring device at the back of the SAU "DP LO (Low) SAU Connection". This 

connection requires a pipe connection between the CU and the SAU25. 

In Leakage Compensation (LC) systems a dedicated Purge Flow Sensor measures the 

differential pressure between the "DP HI (High) / Enclosure Pressure" and the pressure in the 

monitoring device at the back of the RLV "DP LO (Low) RLV Connection". This connection 

requires a pipe to connect the CU to the RLV25. 

4.7 Power Supplies and their Isolation 

All power entering the PE shall be provided with a means of isolation. This requirement also 

applies to any external power sources, which are connected to equipment such as "volt-free" or 

"dry" contacts within the PE. Printer signal, network cards, etc need isolation. 

Exception: Power to other apparatus that is already suitable for the hazardous area need not to 

be isolated by the MiniPurge� system. 

In all cases the application and the isolation of the power must be controlled by the MiniPurge � 

system. Refer to Specification Sheet for output options available. 

4.8 Adjustments and Settings 

Purge Time 

If no specific purge test has been performed on the PE, the volume of the PE must be 

determined by the manufacturer or user and the necessary purging time calculated based on 

the purge flow rate specified by the “standard” being used. It is the user's responsibility to verify 

or enter this data on the PE and/or MiniPurge � system nameplate. Ask Expo if in doubt. The 

IEC / EN 60079-2 permits 5 free volume changes and an example of the calculations is as 

follows: 


Page 8 of 22

If the PE external dimensions indicate an internal free volume of 500 Litres then, 

500 litres enclosure volume x 5 volume changes = 12 minutes purge time 

225 litres/minute purge flow rate 

If the PE is a motor, experience of purge testing shows that it is prudent to multiply the 

motor internal "free” volume by ten to get the purging volume. 

500 litres enclosure volume x 10 volume changes = 23 minutes purge time 

225 litres/minute purge flow rate 

The following applies for NFPA 496 standards where 4 complete volume changes are permitted 

for enclosures except when the PE contains a motor when 10 volume changes are required. 

If the PE external dimensions indicate a total volume of 8 cubic foot, then, 

8 cubic foot enclosure volume x 4 volume changes = 4 minutes purge time 

8 cubic foot/minute purge flow rate, (see above) 

If the same PE contains a motor, then, 

8 cubic foot enclosure volume x 10 volume changes = 10 minutes purge time 

8 cubic foot/minute purge flow rate, (see above) 

Figure 9 MiniPurge � timer block 

The standard MiniPurge � units have the patented digital 

pneumatic timer system as shown in Figure 9 

MiniPurge� timer block. The purge time is set by 

opening / closing the pinch valve so that the sum of the 

open valve times equals or exceeds the required purge 

time. At least one valve must always be open, and 

the screws must be at the appropriate limit of travel. 

Do not over tighten. 

Purge Flow Rate (Orifice Size Selection) – Only for CF Systems 

The purge flow rate is selected by placing the appropriate orifice plate in the SAU. The purge 

flow rates given in Table 2 are based on standard setting of the flow sensor of 2.5mbar, 1” WC, 

250Pa. For LC systems the purge flow rate is set by the selection of the RLV and is not user 

adjustable. 

Continuous Flow Rate with 

2.5 mbarg, 1” WC, 250 Pa 

flow sensor set point 

N litre/minute SCFM 

A 10 0.4 

B 25 0.9 

C 40 1.4 

D 65 2.3 

E 90 3.2 

F 135 4.8 

G 180 6.4 

Orifice Plate 

Number 

NO ORIFICE 225 8.0 

Table 2 Purge Flow Rates 


Page 9 of 22

Action on Loss of Pressurization 

The action on loss of pressurization is the responsibility of the user. 

The action on loss of pressurization can be set to ALARMS ONLY (AO), or ALARM AND 

AUTOMATIC DISCONNECT OF POWER (A&T). 

a) Leakage Compensation 

The action on loss of pressurization is set by moving the 

jumper tube (see Figure 10 Action on Loss of 

Pressurization Jumper Tube). The standard setting is 

Alarm and Trip where the link is from C to A&T, with a 

plug in AO. Changing to Alarm Only (AO) is user 

adjustable by moving the link from C to AO, and plugging 

A&T. 

Figure 10 Action on loss of pressurization jumper tube 

b) Continuous Flow 

The standard CF system is built set to Alarm and Trip. Alarm Only can be installed when order 

specified or supplied as a retrofit kit later. See options. 

The selection for action on loss of pressurization depends on the area of operation and the 

following guidelines should be followed. 

The user must make use of this alarm facility in accordance with the local code of practice for 

"action on pressure or flow failure". Most codes include the following recommendations: 

Zone 1 Installations: 

Alarm and automatic disconnect of power. 

Exception: If the equipment inside the PE is suitable for use in Zone 2, the power trip may be 

performed manually, (no automatic power trip), if the pressure or flow failure persists for an 

unacceptable time. 

Zone 2 Installations: 

Alarm Only on pressure or flow failure with power being removed manually by turning off the air 

supply to the MiniPurge � system if the failure persists for an unacceptable time. 

Class I Division 1 Installations: 

Alarm and Automatic Trip of Power. Note: NFPA 496 states power to the circuits shall be 

permitted to be continued for a short period if immediate loss of power would result in a more 

hazardous condition and if both audible and visual alarms are provided at a constantly attended 

location. 

Class I Division 2 Installations: 

Where automatic timing is preferred, Alarm Only on pressure or flow failure with power being 

removed manually by turning off the air supply to the MiniPurge � system if the failure persists 

for an unacceptable time. 

4.9 Internal Gas Release 

If the PE contains an internal source of release of flammable gas or vapour, the procedures for 

assessment of the release as given in NFPA 496 or IEC / EN 60079-2 should be used. Expo is 

pleased to provide assistance or consultancy and advice on such matters. 

The user must verify that the specifications of the Expo system e.g. pressure, continuous flow 

(dilution) rate and type of protective gas are correct for the specific application. 


Page 10 of 22

4.10 Multiple Enclosures 

More than one PE can be protected by a single system. Where PEs are connected and purged 

in "series" e.g. "Daisy Chained", the RLV and when using a CF system, the SAU25 should be 

fitted on the last enclosure with the Purge Inlet connected to the first enclosure. The bore and 

length of the pipe or conduit used to interconnect the enclosures is critical and will determine 

the maximum pressure experienced by the first enclosure in the series. Advice on sizing can be 

obtained from the Expo sales office but in general terms when using RLV25 or SAU25, the pipe 

bore size should not be less than 25mm (1”). 

A common fault of installing small bore pipe leads to over pressurizing of all but the last 

enclosure. 

PEs should not be connected in parallel. 

5. Commissioning 

Start by check that the system has been installed in 

accordance with this manual. 

Disconnect the supply pipe from the inlet to the MiniPurge � 

system and blow it through for at least 10 seconds per meter 

(3ft) of length to remove any debris or condensation. 

Connect a temporary pressure gauge or water manometer to 

the PE or MiniPurge � system pressure test point (Remove the 

red plug on the low pressure sensor and connect 4mm OD 

nylon tube). 

Figure 11. PE or MiniPurge � system pressure test point 

Unless a supply shut-off valve has been specially fitted inside the MiniPurge � system, it may be 

advisable to install an external shutoff valve with the same, or larger, thread size as the 

MiniPurge � CU inlet fitting upstream of the connection. 

5.1 Continuous Flow (CF) Systems 

Open the Flow Control Valve (FCV) until the alarm/pressurized indicator just turns from red to 

green. Clockwise will reduce the flow and anti-clockwise will increase the airflow. 

If the FCV is opened fully and the indicator has still not turned green, check the air supply 

pressure at the inlet to the control unit while flow is taking place. It must be above the 

minimum 4 bar/ 60 psig/ 400kPa specified. 

Figure 12. Flow Control Valve (FCV) 

Check that the internal logic gauge reads 2bar /30 psig/200kPa. 

The purge timer will start as soon as the ‘alarm/pressurized’ 

indicator turns from red (alarm) to green (pressurized). Check that 

the time delay between the indicator turning green and the 

application of power to the PE is not less than the minimum time 

required to purge the PE. When the purge time has been 

completed, the ‘purge complete’ indicator will turn from red to 

green. 

After the power has been turned on by the CU, the air flow will 

continue at the same rate to provide dilution as required. 


Page 11 of 22

5.2 Leakage Compensation Systems (LC) 

Figure 13 Leakage Compensation Valve 

Open the Leakage Compensation Valve (LCV) fully, turn anti-clockwise. 

Clockwise will reduce the flow and anti-clockwise will increase the airflow. 

Open the supply regulator SLOWLY and allow the PE pressure to rise until 

the RLV opens. Check that the RLV opens at or below the figure specified 

in the documentation. 

Note tolerance of � 2 mbarg / 0.8” WC / 200Pa 

Repeat the test several times. 

Open the supply regulator to between 4 and 8 barg / 60 and 115 psi / 400 

and 800 kPa and the purging flow will start. 

Check that the internal logic gauge reads 2 bar /30 psi / 200 kPa 

At this time the "alarm/pressurized” indicator should be green and the "purging” indicator should 

be yellow. If the yellow indicator remains black the flow through the RLV is below the minimum 

for which the flow sensor has been calibrated. Check the air supply pressure at the inlet to 

the control unit while purging is taking place. It must be above the minimum specified. 

The purge timer will start as soon as the "purging" indicator turns yellow. Check that the time 

delay between the “purging” indicator turning yellow and the application of power to the PE is 

not less than the minimum time required purging the PE. Times in excess of the minimum are 

permitted and a tolerance of +20% is normally acceptable. If the time is too short it must be 

increased accordingly. 

After the power has been applied via the CU, the purging valve will close and the air flow into 

the enclosure will be controlled by the LCV. The initial setting of fully open will normally be too 

high. It should now be adjusted to set the PE pressure and leakage. There are three possible 

situations: 

Air continues to come out through the RLV Spark Arrestor after power has been applied in 

considerable quantity. The LCV is much too far open and the air flow is holding the RLV 

open continuously. 

Close the LCV slowly. The PE pressure will start to fall as the flow decreases but eventually 

the RLV will close and the enclosure pressure rise again. At this point the RLV may start to 

open intermittently as the PE pressure rises to the point where it exceeds the RLV opening 

pressure. When the RLV opens the pressure will fall quickly to the point where the RLV recloses 

and the enclosure pressure starts to rise again. This is entirely normal for this type of 

RLV. 

If the RLV is opening intermittently the LCV is slightly too far open. When the RLV opens 

the enclosure pressure falls quickly to the point where the RLV re-closes and the enclosure 

pressure starts to rise again. This is entirely normal for this type of RLV and shows that it is 

working correctly. 

Continue then to close the LCV until the cycling stops and the enclosure pressure starts to 

fall. Carefully adjust the LCV until the PE pressure is approximately 50% of the RLV 

opening pressure and stable. This pressure may be around 5 mbarg / 2” WC / 500 Pa and 

will be the "normal working pressure". 

We recommend that the setting of the minimum pressure sensor be checked at this time. Note 

the position of the LCV knob. (A pencil mark placed on the knob at "12 O'clock” can be used). 

Slowly lower the PE pressure by closing the LCV further, counting the number of turns from the 

"normal working pressure" position. Note the pressure at which the "alarm/pressurized" 

indicator turns from green to red and check that it is not lower than the figure given in the 


Page 12 of 22

documentation. Check also the "alarm" electrical contacts. As soon as the "alarm/pressurized" 

indicator turns red, the system will start to re-purge. If Alarm and Trip function is selected the 

enclosure power will be switched off. 

While it is re-purging return the LCV to its "normal working pressure" position so that, at the end 

of purging, the enclosure pressure should immediately settle down at the correct "normal" 

pressure. 

If, at the end of purging, the PE pressure falls below the minimum pressure sensor setting 

and the LCV is fully open, the system will start to purge again. This is indicative of 

excessive leakage from the enclosure. In this case, check the enclosure for leakage, and 

reduce or eliminate the leaks. This time, at the end of purging, the enclosure should stay 

pressurized and the RLV action is as in a) or b) above. Proceed as described above. 

5.3 Normal operation 

Turn the air supply on or off to start or stop the system. After this the pressurizing and purging 

sequence is entirely automatic 

6. Maintenance of the System 

The maintenance recommended for the system consists of the following items, supplemented 

by any additional local requirements imposed by the local Code of Practice. Expo recommends 

that the commissioning tests be repeated at least every six months. 

In addition the following checks are also recommended at that time: 

Check the RLV and all Spark Arrestors. Remove all debris & corrosion, or replace with a 

spare. 

Check the condition of the air supply filter element. Clean or replace it as necessary. 

At least every two years check the following additional items: 

Apparatus is suitable for the Hazardous Location 

There are no unauthorised modifications 

The air supply must be to the correct quality, refer to section Air Quality 

The interlocks and alarms function correctly 

Approval labels are legible and undamaged 

Adequate spares are carried 

The action on pressure failure is correct 

Pressure sensor calibration 

If it is decided that the minimum pressure /purge flow sensor needs recalibrating it must be 

returned to Expo for this service. 

Filter cleaning 

If the filter element needs cleaning the filter bowl can be unscrewed and removed. The filter 

element also unscrews and can then be cleaned in soapy water. Do not use solvents on any 

part of the filter assembly. 


Page 13 of 22

7. Fault Finding 

If the system does not behave in the manner described above there is a fault. Some of the 

more likely faults are dealt with below. If a cure cannot be affected by following the procedure 

shown below please call Expo (24 hour answering) or your supplier for further assistance. 

The system has been designed for ease of fault finding and the many of the components fitted 

are plug-in or manifold mounted. Check components by substitution only after establishing that 

such action is necessary. If the system is less than 12 months old, parts under warranty should 

be returned to Expo for investigation, with a full report of the fault and the system serial number. 

As with any pneumatic system the greatest enemies are water, oil and dirt in the air supply. For 

this reason the air system must always incorporate a dust and water filter. This can be part of 

the Expo system or can be provided by others. However dirt can enter from other sources and 

it is vital therefore that the procedures described in Section 2 is carried out before using the 

system for the first time, or following any disconnection of the pipe-work. Failure to perform this 

work may cause damage that will not be covered under warranty. 

Before making the following checks verify that both the main air supply pressure to the purge 

system & the regulated pressure to the logic are as specified on the system specification sheet. 

Different flow charts for faulting have been provided for both the CF and LC options. 


Page 14 of 22

Fault Finding (CF) 

Pressurized/Purging indicator 

will not turn green during 

start up 

Is the air supply 

pressure 

incorrect? 

No 

Is the supply 

pipe to the air 

inlet as least 

12mm I.D? 

Yes 

Is there 

excessive 

leakage from 

the PE? 

No 

Is the PE 

strong enough? 

Yes 

Is the Pressure / 

Flow Sensor out 

of calibration or 

faulty? 

No 

Call Expo 

Yes 

Yes 

No 

Yes 

No 

Check the air 

supply pressure 

at the inlet to the 

MiniPurge is 

stable between 

4 - 8 Barg / 

60 - 115 psi 

Replace pipe 

work 

Any significant 

leakage must be 

corrected. Check 

for leaks down 

the cables or 

conduit. Ensure 

leakage does not 

exceed 60 Nl/min 

(25 cfm) 

The standard 

requires that the 

PE is tested to 

1.5 times the 

Relief Valve 

opening pressure 

e.g. 15 mbarg for 

many systems. 

Has this been 

done? 

The basic operation of the Pressure Sensor 

can be checked by unscrewing the 60mm 

diameter diaphragm housing and, by using a 

rubber pad, e.g. an eraser, block the 12mm 

threaded hole in the top of the valve module. 

The valve should operate and the indicator 

turn green. If this is correct, the sensor 

diaphragm needs recalibrating or replacing. 


Page 15 of 22

System fails to switch power 

on after the purge time has 

elapsed. 

Is Power 

available? 

Yes 

Is Power 

isolator closed? 

Yes 

Are the fuses or 

circuit breaker? 

OK? 

Yes 

Has the purge 

time completed 

its course? 

Yes 

For PO option only 

Is there pressure at the 

power switch output 

bulkhead and at the 

power switch? Is the 

power switch OK? 

Yes 


Is the tube to the 

power switch air 

tight? 

Yes 

Is the Purge 

time correct? 

Yes 


No 


Page 16 of 22 

No 

No 

No 

No 

No 

No 

Check the small 

indicator button 

on the timer 

valve. When the 

valve has timed 

out, it should 

return out when 

depressed. 

Check if the 

external Power 

Switch contacts 

close at 1.4 Barg 

Ensure fitting nuts 

are tightened and 

that the tube is 

not damaged. 

Check and repair 

as necessary. 

Note the timer setting. Reset the timer to the 

minimum available purging period and check 

the operation on that purge time. 

Ensure that the purge time is returned to 

its original setting and checked before 

putting the system back into service.

Relief Valve opens 

continuously or 

intermittently. 

Is the Pressurized 

Enclosure 

pressure too 

high? 

No 

Is there debris on 

the RLV disk 

allowing air to 

leak from the 

valve? 

No 


The Flow Control Valve 

(FCV) is too far open. 

Adjust the FCV 

clockwise to reduce the 

PE pressure 

Remove the RLV cover 

and clean the valve 

disk. If it is necessary to 

remove the disk and 

spring from the RLV, 

draw a line around it 

with a pencil to allow 

accurate replacement 

before removal, 

otherwise the opening 

pressure may be 

affected. 


Page 17 of 22 

Yes 

Yes

Fault Finding (LC) 

System purges correctly 

but the alarm comes on 

at the end of purge time 

and the purging cycle is 

repeated. 

Yes 

Is the actual PE 

pressure below 

the setting of the 

Minimum 

Pressure Sensor? 

No 

Is the Leakage 

Compensation 

Valve setting too 

low causing the 

MiniPurge to 

auto-repurge? 

No 


Check the PE pressure 

with a manometer or 

gauge. 

Increase the PE 

pressure by turning the 

Leakage Compensation 

Valve anti-clockwise. 


Page 18 of 22 

Yes 

Yes

Purging indicator will not 

turn "Yellow" during 

Purging. 

Is the air supply 

pressure 

incorrect? 

No 

Is the supply 

pipe to the air 

inlet as least 

12mm I.D? 

Yes 

Is there 

excessive 

leakage from 

the PE? 

No 

Is the PE strong 

enough? 

Yes 

Is the tube 

between the RLV 

tapping and flow 

sensor air tight? 

Yes 


Flow Sensor out 

of calibration or 

faulty? 

No 


Yes 

Check the air 

supply pressure 

at the inlet to the 

MiniPurge is 

stable between 

4 - 8 Barg / 

60 - 115 psi 


Page 19 of 22 

Yes 

No 

Yes 

No 

No 

Replace pipe 

work 

Any significant 

leakage must be 

corrected. Check 

for leaks down 

the cables or 

conduit. Ensure 

leakage does not 

exceed 60 

Nl/min (25 cfm) 

The standard 

requires that the 

PE is tested to 

1.5 times the 

Relief Valve 

opening 

pressure e.g. 15 

mbarg for many 

systems. Has 

this been done? 



that the tube is 

not damaged. 

Check and repair 

as necessary. 

The basic operation of the Purge Flow 

Sensor can be checked by unscrewing the 

60mm diameter diaphragm housing and, by 

using a rubber pad, e.g. an eraser, block 

the 12mm threaded hole in the top of the 

valve module. The valve should operate 

and the indicator turn amber. If this is 

correct, the sensor diaphragm needs 

recalibrating or replacing.

System fails to switch power 

on after the purge time has 

elapsed. 

Is Power 

available? 

Yes 

Is Power 

isolator closed? 

Yes 

Are the fuses or 

circuit breaker? 

OK? 

Yes 

Has the purge 

time completed 

its course? 

Yes 


Is there pressure at the 

power switch output 

bulkhead and at the 

power switch? Is the 

power switch OK? 

Yes 


Is the tube to the 

power switch air 

tight? 

Yes 


time correct? 

Yes 


No 

No 

No 

No 

No 

No 

Check the small 

indicator button 

on the timer 

valve. When the 

valve has timed 

out, it should 

return out when 

depressed. 

Check if the 

external Power 

Switch contacts 

close at 1.4 Barg 



that the tube is not 

damaged. Check 

and repair as 

necessary. 

Note the timer setting. Reset the timer to the 

minimum available purging period and check 

the operation on that purge time. 

Ensure that the purge time is returned to 

its original setting and checked before 

putting the system back into service. 


Page 20 of 22 

No

Relief Valve opens 

continuously or 

intermittently. 

Is the Pressurized 

Enclosure 

pressure too 

high? 

No 

Is there debris on 

the RLV disk 

allowing air to 

leak from the 

valve? 

No 


The Leakage 

Compensation Valve 

(LCV) is too far open. 

Adjust the LCV 

clockwise to reduce the 

PE pressure 

Remove the RLV cover 

and clean the valve 

disk. If it is necessary to 

remove the disk and 

spring from the RLV, 

draw a line around it 

with a pencil to allow 

accurate replacement 

before removal, 

otherwise the opening 

pressure may be 

affected. 


Page 21 of 22 

Yes 

Yes

8. Approval Documents 

System Approval Authority Certificate Number 

MiniPurge � IECEx SIR 07.0027X 

Sira 01ATEX 1295X 

INMETRO/TUV TÜV 12.1462X 

FM 1X8A4.AE 

UL E190061 

For PA Option Only Approval Authority Certificate Number 

Ex e junction box IECEx IECEx ITS10.0003X 

ATEX ITS 10 ATEX 37092X 

TUV TÜV 12.1463 

Ex d switches IECEx PTB IECEx PTB07.0045X 

PTB 00 ATEX 1093 X 

Bartec 01-2511-7C0001 

9. Glossary 

Acronym Description 

A&T Alarm and Trip 

AO Alarm Only 

CF Continuous Flow 

CU Control Unit 

FCV Flow Control Valve 

FM Factory Mutual 

IS Intrinsically Safe 

LC Leakage Compensation 

LCV Leakage Compensation Valve 

MIU MiniPurge � Interface Unit 

PA Ex d Power and Alarm Switch Wired to Ex e terminal box 

PE Pressurized Enclosure 

PO Pneumatic Output 

RLV Relief Valve 

SAU Spark Arrestor Unit 

UL Underwriter Laboratories 


Page 22 of 22

The contents of this drawing / document are Copyright © Expo Technologies Limited. They are to be treated as confidential 

and are returnable upon request. They are not to be copied or communicated in part or in whole without written consent 

from Expo Technologies Limited, neither are they to be used in any way against our interests. 

UNSPECIFIED NO DEC PLACE ±0.5 

TOLERANCES 1 DEC PLACE ±0.2 

2 DEC PLACE ±0.1 

FLATNESS TO BE LESS THAN 0.4mm OVER ANY 100mm LENGTH 

DIMENSIONS IN mm 

DO NOT SCALE 

3rd ANGLE 

PROJECTION 

PRESSURIZED INDICATOR 

Pressurized Enclosure door closed 

Red = Pressure Low 

"Pressurized" signal absent i.e. "Alarm" ON 

Turn Pressurizing air or inert gas on 

Enclosure door opened, or excessive leakage 

Pressurizing air or inert gas turned off 

Air enters the PE 

Enclosure pressure falls below the minimum 

No 

Is the PE pressure above the minimum? 

Low Pressure sensor turns off 


Action taken on pressure failure 


depends upon the user. Actions 

include:- Alarm and/or Trip 

Alarm and delayed trip Power turned off automatically without delay "Pressurized" signal absent i.e. "Alarm" ON 

Yes 


Low Pressure sensor turns on 

Green = Pressure OK 

Relief Valve opens Purge flow starts "Pressurized" signal to remote alarm switch 

No 

Purge Outlet flow above the minimum? 

Yes 

Purge Flow Sensor turns on 

Purge timer resets 

"Purging" Indicator 

Amber = Purge flow OK 

Black = Purge flow too low 

Purge timer starts automatically 

No 

Outlet flow still above the minimum? 

Key to functions 

Yes 

Purge timer times out 

Manual operation by the user 

Purge valve closes; Power Sw. signal ON 

Automatic operation by the system 

"Purge Complete" signal to electrical Power Switch 

Purge flow ceases; Relief Valve closes 

Optional operation (User decision) 

Purging Indicator turns Black as 

Purge flow falls below minimum 

Leakage Compensation starts 

THIS DRAWING IS REFERENCED TO 

EXPO CETIFICATION DRAWING EP99-2-3 

Power on - Normal operation 

REV: 

01 

1:1 

SCALE 

SURREY KT7 0RH 

UNITED KINGDOM 

Expo Technologies Limited 

MATERIAL 

23/06/2010 

DRAWN DATE: 

REV. MOD NUMBER APPROVED DATE APPROVED 

Controlled 

DRAWING No. 

TITLE 

DRAWING STATUS: 

XBR-7TD0-040 

1 

MINIPURGE X LC SEQUENCE DIAGRAM 

FINISH 

CUSTOMER: 

JOB No: 

SHEET No. OF 1 

APP'D CHK'D DR'WN 

JPdB PSC BRD 

01 DRAWN 23/06/2010 JPdB

The contents of this drawing / document are Copyright © Expo Technologies Limited. They are to be treated as confidential 

and are returnable upon request. They are not to be copied or communicated in part or in whole without written consent 

from Expo Technologies Limited, neither are they to be used in any way against our interests. 






3rd ANGLE 

PROJECTION 

DO NOT SCALE 

Enclosure door opened, or excessive leakage 

Pressurizing air or inert gas turned off 



Pressurized Enclosure door closed 

Enclosure pressure or Flow 

fall below the minimum 

"Pressurized/Flow" signal absent i.e. "Alarm" ON 

Turn Pressurizing air or inert gas on 

Pressurized/Flow Indicator 

Red = Pressure/Flow Low 

Low Pressure/Flow sensor turns off 

Air enters the PE 

"Pressurized/Flow" signal absent i.e. "Alarm" ON 

Power turned off automatically 

with/without delay 

Enclosure pressure and the purge outlet 

flow above the minimum specified? 

No 

Action taken on Pressure/Flow 

failure depends upon the user. 

Actions include:- Alarm and/or 

Trip Alarm and delayed trip 

Yes 


Green = Pressure/Flow OK 

Low Pressure sensor turns on 

Purge timer resets 

"Pressurized/Flow" signal to remote alarm switch 

Purge timer starts automatically 

No 

Purge Outlet flow above the minimum? 

Yes 

Purge timer times out 

Power On Indicator turns 

Green at "Purge Complete" 

Power Sw. signal ON 

Possible "Action on Pressure/Flow 

Failure" (user decision) 

"Purge Complete" signal to electrical Power Switch 

Power on 

Key to functions 

Continuous Flow/ Dilution Flow starts 

Manual operation by the user 

Purge flow ceases; Relief Valve closes 

No 

Automatic operation by the system 

Outlet flow still above the minimum? 

Yes 

Optional operation (User decision) 

Power on - Normal operation 

THIS DRAWING IS REFERENCED TO 

EXPO CERTIFICATION DRAWING EP99-2-4 

REV: 

1:1 01 

SCALE 




MATERIAL 

23/06/2010 

DRAWN DATE: 

REV. MOD NUMBER APPROVED DATE APPROVED 

XBR-7TD0-041 

Controlled 

TITLE 

DRAWING No. 

APP'D CHK'D DR'WN FINISH 

MINIPURGE X CF SEQUENCE DIAGRAM 

JPdB PSC BRD 

JOB No: 

CUSTOMER: 

SHEET No. 1 OF 1 

DRAWING STATUS: 

01 DRAWN 23/06/2010 JPdB

1) 

2) 

3) 

133 [5 1 4 "] 

MiniPurge 

CONFIGURATION 

NOTES: 

USE DIRECT MOUNTING WHEREVER 

POSSIBLE, WALL MOUNTING 

BRACKETS AND PIPING KITS FOR 

SIDE MOUNTING ARE OPTIONAL. 

MINIPURGE MUST BE MOUNTED IN 

THE POSTIONS SHOWN. 

PURGE AIR TO VENT INTO TOP OF 

ENCLOSURE AND EXIT THROUGH 

RELIEF VALVE /SPARK ARRESTOR 

AT THE BOTTOM OF THE 

ENCLOSURE. 

D.P. LO 

6mm OR M5 (10-32 UNF) 

FITTING SUPPLIED 

33 [1 5 

"] 

5 

16 

29 [1 

32 "] 

PURGE OUTLET 

DO NOT OBSTRUCT 

LC OPTION ONLY. 

FLOW MONITORING 

PIPE REQUIRED 

RLV 25 RELIEF VALVE 

44 [1 23 

32 "] 

FOR LC 

SYSTEMS 

ONLY 

GASKET 

HOUSING 

PANEL 

MOUNT 

(OPTIONAL) 

RLV25 RELIEF VALVE 

WEIGHT = 0.5 kg (1.1 lb) 

M5 FIXINGS SUPPLIED 

Ø6 (Ø1/4") HOLES REQUIRED 

IN ENCLOSURE. 

HOLE Ø25(1") REQUIRED 

IN ENCLOSURE 

44 [1 23 

32 "] 

62 [2 15 

32 "] 

CUTOUT DETAILS VIEWED 

FROM INSIDE ENCLOSURE 

46 [1 13 

16 "] 

ALARM 

(RED) 

ALARM ALARME 

(ROT) (ROUGE) 

PRESSURIZED 

PURGING 

(GREEN) 

(YELLOW) 

PRESSURISE DRUCK OK EN BALAYAGE VORSPÜLUNG 

(VERT) (GRÜN) (JAUNE) (GELB) 

EN50 016:1977 (BS 5501 pt 3) 

EEx p II SCS Certificate Ex 94C1052U 

BS EN50016:1995 (2nd edition) 

[EEx p] II Sira Certificate Ex99E1002U 

SAU25 SPARK ARRESTOR 

WEIGHT = 0.2 kg (0.44 lb) 

D.P. LO 

6mm OR M5 (10-32 UNF) 

FITTING SUPPLIED 

M25 X 1.5P THREAD 

Ø26mm (1") CLEAREANCE 

HOLE REQUIRED IN 

ENCLOSURE 

35 [1 3 8 "] 

55 [2 5 

"] 

32 

25 [31 

32 "] 

DIRECT MOUNT (PREFERRED OPTION) 

SIDE 

MOUNT 

PIPING KIT 

(OPTIONAL) 

CF OPTION 

SAU 25 SPARK 

ARRESTOR 

(CF OPTION ONLY) 

ORIFICE PLATE 

AND CIRCLIP 

SEE NOTE 

GASKET 

SPARK 

ARRESTOR 

BODY 

NOTE:- 

SYSTEMS SUPPLIED WITHOUT ENCLOSURES ARE 

SUPPLIED WITH A RANGE OF 8 ORIFICE PLATES TO SUIT 

FLOW RATES BETWEEN 10-225 NL/MIN (0.4-8 SCFM) 

XBR-7TD0-003 ISSUE 4 

Sub MiniPurge Systems 

CONFIGURATION

The contents of this drawing / document are Copyright © Expo Technologies Limited. They are to be treated as confidential and are returnable 

upon request. They are not to be copied or communicated in part or in whole without written consent from Expo Technologies Limited, neither 

are they to be used in any way against our interests. 






DO NOT SCALE 

3rd ANGLE 

PROJECTION 

35 [1.30"] APPROX. 

MOUNTING BAR PITCH = 180 [7.09"] 

150 [5.91"] 

PURGE 

INDICATOR 2 

ALARM 

INDICATOR 1 

MOUNTING BAR 

(SPECIAL OPTION ONLY) 

129 [5.08"] 

INDICATORS 

PURGE 

COMPLETE 

PURGING 

PRESSURIZED 

ALARM 

MOUNTING BAR PITCH = 210 [8.27"] 

MiniPurge 

1 2 

BLACK 

YELLOW 

GREEN 

RED 

LEAKAGE 

COMPENSATION 

(LC) 

155 [6.10"] 

PA. OPTION 

CUSTOMER TO 

SITE AND DRILL 

INPUT GLAND 

HOLE 

180 [7.09"] 

GREEN 

RED 

GREEN 

RED 

CONTINUOUS 

FLOW (CF) 

www.expoworldwide.com 

BLACK 

YELLOW 

GREEN 

RED 

CONTINUOUS 

FLOW AFTER 

HIGH PURGE 

(CFHP) 

102 [4.02"] 

8 [0.31"] 

APPROX. 

REMOVABLE COVER 

45 [1.77"] 

PO. OPTION 

PURGE OUTLET 1/2" NPTF 

D.P. HI / ENCLOSURE PRESSURE 1/8" NPTF 

(LC OPTION ONLY) 

35 [1.30"] 

APPROX. 

HOLE Ø7.5 [Ø0.30"] 

FOR M6 OR 

1/4" FIXING 

POWER INTERLOCK 

SIGNAL 

1/8" NPTF 

D.P. LO / RLV OR SAU CONNECTION 1/8" NPTF 

HOLE SUITABLE FOR GLAND M20 OR 1/2" NPT 

AIR SUPPLY 4 - MAX 8 barg [60-115 psi] 

1/2" NPTF 

[1.38"] 

35 

65 [2.56"] 

37 

[1.46"] 

PASSIVE ALARM 

/ PRESSURIZED 

SIGNAL 

1/8" NPTF 

90 [3.54"] 

75 [2.95"] 

5 [0.20"] 

96 [3.78"] 

IS. OPTION 

HOLE SUITABLE 

FOR GLAND M20 OR 

1/2" NPT 

NOTES 

MINIPURGE MUST BE MOUNTED WITH PURGE OUTLET FITTING IN 

65 [2.56"] 

8 [0.31"] APPROX. 

1. 

120 [4.72"] 

VERTICAL PLANE POINTING DOWN. 

[1.61"] 

41 

155 [6.10"] 

APPROXIMATE WEIGHT: 5.5 kg [12.1 POUNDS]. 

2. 

EQUIVALENT IMPERIAL DIMENSIONS SHOWN IN BRACKETS. 

3. 

185 [7.28"] 

REFER TO DRG XSD-7TD0-001 FOR MOUNTING DETAILS. 

240 [9.45"] 

SCALE 




MATERIAL 

STAINLESS STEEL 

1 

DRAWN 

DRAWING No. 

TITLE 

FINISH 

1 3 

CUSTOMER: 

JOB No: 

NROB 

5 

4657 

2/4/09 

JPdB 

4 

4385 

21/12/07 

JPdB 

3 

4353 

13/09/07 

SHEET No. OF 

MJF JPdB 

NON CERTIFIED 

ISSUE: 

MOD. No: 

DATE: 

APPROVED: 

DRAWING STATUS:




NO DEC PLACE ±0.5 



UNSPECIFIED 

TOLERANCES 


DO NOT SCALE 

3rd ANGLE 

PROJECTION 


LC LEAKAGE COMPENSATION SHOWN (ITEMS IN DOTTED REMOVED FOR CF) 

TO RESERVOIRS 

8 

9 

76 

2 18 13 3 7 

TIMER 

PINCH 

VALVES 

1 

PURGE TIME SELECTOR 

DOOR INTERNAL 

15 

16 

17 

33 35 

26 

34 

22 

PUSH-IN PLUG 

ENCLOSURE 

PRESSURE 

TEST POINT 

26 

14 

19 

AO C A&T AO C A&T 

ALARM ONLY 

ALARM AND TRIP 

PLUG 4mm 

26 

MINIMUM PRESSURE SENSOR 

14 

GAUGE, LOGIC AIR SUPPLY 

1 

"ACTION ON ALARM" OPTION PIPE 

33 

MAIN AIR SUPPLY FILTER, MANUAL DRAIN 

15 

LOGIC AIR SUPPLY REGULATOR 

2 

ALARM ONLY PUSH-IN FITTING 

34 

PURGE COMPLETE "OR" GATE 

16 

IN LINE RESTRICTOR 

3 

ALARM AND TRIP PUSH-IN FITTING 

35 

LEAKAGE COMPENSATION VALVE 

17 

BLACK COLLAR (PLUGGED) 

7 

PURGE TIME SELECTOR 

76 

TIMER VALVE 

18 

INDICATOR, "ALARM/PRESSURIZED" 

8 

PURGE BOOST VALVE 

19 

INDICATOR, "PURGING" 

9 

PURGE COMPLETE VALVE (BELOW ITEM 17) 

22 

PURGE FLOW SENSOR 

13 

SCALE 




MATERIAL 

DRAWING No. 

TITLE 

FINISH 

5 

4657 

2/4/09 

JPdB 

4 

4385 

21/12/07 

JPdB 

2 OF 3 

CUSTOMER: 

JOB No: 

SHEET No. 

1 3 

DRAWN 4353 

13/09/07 

MJF JPdB 

NON CERTIFIED 

ISSUE: 

MOD. No: 

DATE: 

APPROVED: 

DRAWING STATUS:




NO DEC PLACE ±0.5 



UNSPECIFIED 

TOLERANCES 


DO NOT SCALE 

3rd ANGLE 

PROJECTION 


PA OPTION PO OPTION 

IS OPTION 

FLOW 

FLOW 

FLOW 

PA BOX 

MIN 

MIN 

MIN 

CLEAR 4mm PIPE TO PASSIVE 

ALARM/PRESSURIZED SIGNAL 

1/8" NPTF CONNECTOR 

Ex d SWITCH WIRED TO ALARM 

TERMINALS IN PA BOX 

TERMINALS FOR CONNECTING I.S. 

CIRCUITS VIA M20 OR 1/2" NPT CABLE 

ENTRY ON LHS OR BOTTOM 

BLUE 4mm PIPE TO POWER 

INTERLOCK 1/8" NPTF CONNECTOR 

Ex d SWITCH WIRED TO POWER 

TERMINALS IN PA BOX 

NOTE: 

LC VERSION SHOWN. (ITEMS IN DOTTED REMOVED FOR CF) 

SCALE 




MATERIAL 

DRAWING No. 

TITLE 

FINISH 

5 

4657 

2/4/09 

JPdB 

4 

4385 

21/12/07 

JPdB 

3 OF 3 

CUSTOMER: 

JOB No: 

SHEET No. 

1 3 

DRAWN 4353 

13/09/07 

MJF JPdB 

NON CERTIFIED 

ISSUE: 

MOD. No: 

DATE: 

APPROVED: 

DRAWING STATUS:

IECEx Certificate 

of Conformity 

INTERNATIONAL ELECTROTECHNICAL COMMISSION 

IEC Certification Scheme for Explosive Atmospheres 

for rules and details of the IECEx Scheme visit www.iecex.com 

Certificate history: 

Issue No. 4 (2011-12-9) 

Issue No. 3 (2011-3-9) 

Issue No. 2 (2011-1-12) 

Issue No. 1 (2009-3-16) 

Issue No. 0 (2007-9-20) 

Certificate No.: IECEx SIR 07.0027X issue No.:4 

Status: Current 

Date of Issue: 2011-12-09 Page 1 of 4 

EXPO Technologies Ltd 

Summer Road 

Thames Ditton 

Surrey KT7 ORH 

United Kingdom 

Applicant: 

Electrical Apparatus: MiniPurge Purge Controller 

Optional accessory: 

Type of Protection: Pressurised 

Marking: Standard versions: (Ta –20°C to +55°C) 


Ex [py] IIC T6 Gb 

Ex [p] IIIC T85°C Db or 

Ex [pz Gc ] IIC T6 Gb 

Ex [p Dc] IIIC T85°C Db 

Standard /ET versions: (Ta –20°C to +55°C) 

Ex [px] ia IIC T6 Gb 

Ex [p] ia IIIC T95°C Db 

Low temp. versions: (Ta –50°C to +55°C) 

Ex[px]dem IICT3orT4Gb 

Ex [p] IIIC T200°C or T135°C Db 

Low temp. /ET versions: (Ta –50°C to +55°C) 

Ex [px] dem ia IIC T3 or T4 Gb 

Ex [p] ia IIIC T200°C or T135°C Db 

C Ellaby 

Approved for issue on behalf of the IECEx 

Certification Body: 

Position: Deputy Certification Manager 

Signature: 

(for printed version) 

Date: 

1. This certificate and schedule may only be reproduced in full. 

2. This certificate is not transferable and remains the property of the issuing body. 

3. The Status and authenticity of this certificate may be verified by visiting the Official IECEx Website. 

Certificate issued by: 

SIRA Certification Service 

Rake Lane 

Eccleston 

Chester 

CH4 9JN 

United Kingdom

CERTIFICATION 

CERTIFICATION 

SCHEDULE 

1 EC TYPE-EXAMINATION CERTIFICATE 

EC TYPE-EXAMINATION CERTIFICATE Sira 01ATEX1295X 

Issue 7 

2 Equipment intended for use in Potentially Explosive Atmospheres Directive 94/9/EC 

13 DESCRIPTION OF EQUIPMENT 

The Purge Controllers are pneumatically operated devices, which are intended to provide a given flow rate of 

purging gas for a predetermined time to unspecified Ex p protected electrical equipment. The MiniPurge 

Control Units provide one of the following four methods of purge operation. 

3 Certificate Number: Sira 01ATEX1295X Issue: 7 

4 Equipment: Purge Controllers: Sub-MiniPurge, MiniPurge, Super-MiniPurge, 

Super-MiniPurge 1800/3500/7000/7000X 

5 Applicant: EXPO Technologies Limited 

LC-Leakage compensation only after initial high purge 

CF-Continuous flow (same flow rate during and after purging) 

CF2-Two flow CF system with initial high purge rate only at one orifice 

CFHP-Continuous (lower) flow after initial high purge 

The MiniPurge control unit may be supplied within a heated enclosure to permit the use of the system within 

an ambient temperature down to –50 o C. 

The MiniPurge option pD is for use in combustible dust 

6 Address: Summer Road, Thames Ditton, Surrey KT7 ORH, UK 

7 This equipment and any acceptable variation thereto is specified in the schedule to this certificate and 

the documents therein referred to. 

8 Sira Certification Service, notified body number 0518 in accordance with Article 9 of Directive 94/9/EC of 23 

March 1994, certifies that this equipment has been found to comply with the Essential Health and Safety 

Requirements relating to the design and construction of equipment intended for use in potentially explosive 

atmospheres given in Annex II to the Directive. 

The examination and test results are recorded in the confidential reports listed in Section 14.2. 

Relief Valve - The MiniPurge controller is supplied with an optional overpressure relief valve,whichistobe 

fitted to the Ex p protected apparatus to prevent an internal overpressure above the maximum overpressure 

rating of the apparatus. There are 14 models of relief valve; the designation of each relief valve refers to its 

nominal bore in mm, as follows: 

9 Compliance with the Essential Health and Safety Requirements, with the exception of those listed in the 

schedule to this certificate, has been assured by compliance with the following documents: 

IEC 60079-0:2011 EN 60079-2:2007 EN 61241-4: 2006 

RLV3, RLV6, RLV9, RLV12, RLV19, RLV25, RLV26, RLV52, RLV36, RLV75, RLV104, RLV125, RLV150 and 

RLV200. 

10 If the sign ‘X’ is placed after the certificate number, it indicates that the equipment is subject to special 

conditions for safe use specified in the schedule to this certificate. 

The outlet of each relief valve is fitted with a spark arrestor, of which there are four optional types: 

� Metal foam � Multi-layer stainless steel mesh 

� Tortuous path with at least 4 x 90�or 2 x 180� bends � Knitted mesh 

11 This EC type-examination certificate relates only to the design and construction of the specified equipment. If 

applicable, further requirements of this Directive apply to the manufacture and supply of this equipment. 

12 The marking of the equipment shall include the following: 

Outlet Orifice - Three types of orifice are used: 

� Threaded Orifices e.g. ¼� NPT or 2� BSP with a built in spark arrester. These are selected to maintain a 

desired back pressure within the Ex p protected apparatus when used with the Continuous Flow options. 

Thedesignationofeachoutletorificeindicatesthenominalinletdiameter. Thedesignationsareas 

follows: SA3, SA6, SA9, SA12, SA19, SA25, SA32, SA38 and SA50. 

� Plain holes in the Relief Valve disk, sizedaccordingtotheflow rate required. 

� Replaceable orifice type SAU**. 

Standard versions Low temperature versions 

II 2(2) GD II 2(2) GD 

Ex [px] IIC T6 Gb Ex [px] dem IIC T3 or T4 Gb 

Ex [py] IIC T6 Gb Ex [p] IIIC T200°C or T135°C Db 

Ex [p] IIIC T85°C Db (Ta –50°C to +55°C) 

(Ta –20°C to +55°C) 

High Pressure Sensor for CF Systems (HP code) - If the pressure in the pressurized enclosure 

rises above the setting of the High Pressure sensor, the controller resets cutting the power to the 

enclosure. On detecting the overpressure an optional facility is available for the generation of an alarm 

or indicator. On systems with a High Pressure sensor, the relief valve may be omitted. 

II 2(3) GD 

Ex [pz Gc ] IIC T6 Gb 

Ex [p Dc] IIIC T85°C Db 

(Ta –20°C to +55°C) 

Standard /ET versions Low temperature /ET versions 

High Pressure Sensor for LC Systems (HP code) - If the pressure in the pressurized enclosure 

rises above the setting of the High Pressure sensor, the purge gas flow is isolated from the pressurised 

enclosure. The valve isolates both the leakage compensation and the purge streams. On detecting the 

overpressure, an optional facility isavailableforthegenerationofanalarm or indicator. On systems 

with a High Pressure sensor, the relief valve may be omitted. 

II 2(2) GD 

II 2(2) GD 

Ex [px] ia IIC T6 Gb Ex [px] dem ia IIC T3 or T4 Gb 

Ex [p] ia IIIC T95°C Db Ex [p] ia IIIC T200°C or T135°C Db 

(Ta –20 o Cto+55 o C) (Ta –50°C to +55°C) 

Pneumatically Operated Outlet Valve - The pneumatically operated outlet valve is used to 

positively open or close the outlet of the purged enclosure by means of a spring return pneumatic 

cylinder. Systems fitted with the Pneumatically Operated Outlet Valve will carry the option OV. 

Project Number 25983 C Ellaby 

Deputy Certification Manager 

This certificate and its schedules may only be 

reproduced in its entirety and without change. 

Sira Certification Service 

Rake Lane, Eccleston, Chester, CH4 9JN, England 





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Email: info@siracertification.com 

Web: www.siracertification.com 

Page 2 of 7 

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Form 9400 Issue 1 

Form 9400 Issue1

CERTIFICATION 

CERTIFICATION 

SCHEDULE 

SCHEDULE 


Issue 7 


Issue 7 

Variation 1 This variation introduced the following changes: 

i. The purge controller to be fitted inside an additional, heated, stainless steel enclosure that allows 

it to be used down to -50 o C. 

The heater (500 W maximum) is manufactured by Intertec-Hess GmbH and coded Ex d m IIC T3 

(max) under PTB 02ATEX1041X. If the outer enclosure is reduced in size the power of the heater 

may be reduced in proportion to the reduction in surface area. Other alternative heaters may be 

used as a replacement if they are suitably certified, carry the same or greater ambient 

temperature range, occupy the same or smaller physical space, have the same certification code 

and have the same or more restrictive Temperature Class. 

The enclosure is made from 1.5mm or 2.5 mm thick stainless or mild steel painted and the lid is 

made from 1.5 mm thick stainless steel, lined with 38 mm thick insulation, or other materials with 

equivalent insulating properties. The purge inlet, purge outlet and pressure sensing lines are 

similarly insulated. The door may optionally be hinged with quick release catches, these will be 

fitted with a padlock. An enclosure breather tube is fitted to help prevent condensation. A plastic 

clear viewing window may optionally be fitted to the door. 

RTDs are fitted to the air inlet pipe-work and inside the purge controller enclosure. 

An Ex e terminal box is provided within the main enclosure for connection of the heater leads. This 

polyester box is manufactured by Bartec and coded Ex e II T6 under BAS 98ATEX3008X. Other 

alternative ATEX terminal boxes may be used as a replacement if they are suitably certified, carry 

the same or greater ambient temperature range, occupy the same or smaller physical space, have 

the same certification code and have the same Temperature Class. 

Model Number Designation for ATEX approved MiniPurge systems 

a Size or Capacity 

1 Sub-MiniPurge 

Model Number: 

2 MiniPurge 

1 X LC cs DS SS AA MO FM OA TW 

3 Super-MiniPurge 

4 Super-MiniPurge 1800 

Key: 


a b cc mm Example option codes 


7 Super-MiniPurge xxxx 

b Pressurization Type 

X X Pressurization 

Y Y Pressurization 

Z Z Pressurization 

cc Action after initial purging 

LC Leakage Compensation only after initial High Purge 

CF Continuous Flow (same flow rate during and after purging) 

CF2 Two Flow CF system with initial High Purge rate but only one orifice 

CFHP Continuous (lower) Flow after initial High Purge 

DP Dust Protection (pressurization only) 

mm Material of the Control Unit Enclosure 

al Aluminium alloy 

cs Mild steel, painted 

ss Stainless steel 

bp Back Plate only 

co Chassis only 

pm Panel mounting 

nm Non-Metallic 

Option codes (Added only if used) 

AA Active Alarm output fitted. 

AC Alarm cancellation circuit. 

AO "Alarm Only" Action on Pressure or Flow Failure. 

AS Alarm "Action on Pressure or Flow failure", Selector valve. 

CS Containment System Monitor. 

DS Door switch Power Interlock fitted. 

DT Delayed Trip after Pressure or Flow failure. 

DXXX Special design for specific flow rates 

ET Electronic Timer 

FM Flow Meter(s) fitted. 

HP System LC or CF with High Pressure Sensor 

IS Internal Switches suitable for Ex i circuits. 

MO Manual Override fitted. 

MT Mechanical Timer. 

OA On/Off switch controlling Protective gas and logic supply. 

OB On/Off switch controlling logic supply only. 

OC On/Off switch controlling Protective gas supply only. 

OS Outlet (Orifice) Selector valve. 

OV Outlet valve, pneumatically operated. 

PA "Ex" switch(es) built-in, with/without "Ex" junction box. 

PC PE Pressure Control Leakage Compensation Valve (CLAPS System.) 

PO Pneumatic Output signals for Power and Alarm control. 

SP Secondary Pressurization supply options. 

SS Separate Supply for Protective gas and Logic air. 

TW Twin (or more) outputs for two or more separate pressurized enclosures purged in parallel 

Any suitably ATEX, Category 2 approved cable glandmaybeused,ifitcanbeusedwiththe 

ambient temperature range. 

ii. A change of the Applicant’s name on the certificate and the substitution of the new name for the 

old name on the approved label affixed to the purge controllers: 

Old Name: New name: 

Expo Telektron Safety System Limited Expo Technologies Limited 

Variation 2 This variation introduced the following change: 

i. To permit the pressurisation of enclosures for the exclusion of combustible dusts in accordance 

with IEC61241-4:2001 and modification of the marking to include one of the following: 

[Ex pD] II T200°C 21 (Ta = -20°C to +55°C) - (used with the low temperature versions) 

[Ex pD] II T85°C 21 (Ta = -20°C to +55°C) - (used with the standard temperature versions) 

The ATEX coding is modified to: II 2(2) G D 









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Page 3 of 7 

Form 9400 Issue1 

Form 9400 Issue1

CERTIFICATION 

CERTIFICATION 

SCHEDULE 

SCHEDULE 


Issue 7 


Issue 7 

Issue Date Report no. Comment 

4 7 June 2007 R51L15966B This Issue covers the following changes: 

� All previously issued certification was rationalised 

into a single certificate, Issue 4, Issues 0 to 3 

referenced above are only intended to reflect the 

history of the previous certification and have not 

been issued as documents in this format. 

� The introduction of Variation 3. 

5 18 February 2009 R51L19695A The introduction of Variation 4. 

6 22 December 2010 R23665A/00 This Issue covers the following changes: 

� This certificate history was modified to recognise 

that that Variation 2 was re-issued, subsequent 

Variations have therefore been re-numbered. 

� The introduction of Variation 5. 

7 07 December 2011 R25983A/00 The introduction of Variation 6. 

Variation 3 This variation introduced the following changes: 

i. Following appropriate re-assessment to demonstrate compliance with the requirements of the EN 

60079 series of standards, the documents originally listed in section 9, EN 50014:1997 

(amendments A1 to A2) and EN 50016:1995, were replaced by EN 60079-0:2006, EN 60079-1:2004, 

EN 61241-0:2006 and EN 61241-1:2006, the markings in section 12 were updated accordingly. 

ii. The removal of special conditions for safe use that were not specifically associated with the 

equipment covered by this certificate. 

Variation 4 - This variation introduced the following changes: 

i. To permit the inclusion of the following coding for the Low Temperature MiniPurge Enclosure: 

Ex [p] dem IIC T4 

Ex pD II 21 T135°C 

(Ta –50 o Cto+55 o C) 


15 SPECIAL CONDITIONS FOR SAFE USE (denoted by X after the certificate number) 

15.1 When using the AO, AS and DT options, the recommendations for the additional requirements of Ex p 

apparatus contained within EN 60079-14 shall be applied. 

i. The introduction of the /ET version, an alternative to the pneumatic or mechanical timer system, 

this incorporates an Electronic Timer Module ETM-IS**-*** in the Mini Purge, the certification 

includes ‘ia’ marking when the ETM is fitted. 

ii. The dust marking was changed to be consistent with the marking for gases and vapours. 

iii. The introduction of a high pressure sensor for the LC option. 

15.2 The installer/user shall ensure that the MiniPurge Control Unit is installed in accordance with the 

equipment certificate that covers the combination of the pressurised enclosure(s) and MiniPurge 

Control Unit. 


15.3 The values of the safety parameters shall be set in accordance with the equipment certificate that 

covers the combination of the pressurised enclosure(s) and MiniPurge Control Unit. 

15.4 This MiniPurge Control Unit shall be incorporated into equipment and the appropriate Conformity 

Assessment Procedures applied to the combination as defined by Directive 94/9/EC. This certificate 

does not cover the combination. 

i. Following appropriate re-assessment to demonstrate compliance with the requirements of the 

latest EN 60079 series of standards, the documents previously listed in section 9, EN 60079-0: 

2006 and EN 60079-2: 2004 were replaced by those currently listed (EN 61241-0: 2006 was 

removed as this is incorporated into the current version of 60079-0), the markings in section 12 

were updated accordingly and a new condition of certification was added. 

14 DESCRIPTIVE DOCUMENTS 

15.5 The purge controller, low temperature version, shall be protected by a safety related system that 

ensures that it cannot be energised if the temperature of the air inlet or purge controller falls below - 

20 o C. This system shall utilise the RTDs that are fitted to the purge controller to provide the 

appropriate level of system integrity, i.e. a level of operational safety of Cat 3 according to EN 954-1 for 

ATEX Category 2 (Zone 1) applications; note that these RTDs have not been assessed as a safety 

related device in accordance with EHSR 1.5 of Directive 94/9/EC. 

14.1 Drawings 

Refer to Certificate Annexe. 

14.2 Associated Sira Reports and Certificate History 

16 ESSENTIAL HEALTH AND SAFETY REQUIREMENTS (EHSRs) 

The relevant EHSRs that are not addressed by the standards listed in this certificate have been 

identified and individually assessed reports listed in Section 14.2. 

Issue Date Report no. Comment 

0 3 July 2002 R53A7169A The release of prime certificate. 

1 29 March 2004 R53V11342A The introduction of Variation 1. 

2 30 September 2004 R51A11080A The introduction of Variation 2. 

3 19 September 2006 R51A15629A The re-issue of Variation 2 to include the changes 

described in report number R51A15629A. 

17 CONDITIONS OF CERTIFICATION 

17.1 The use of this certificate is subject to the Regulations Applicable to Holders of Sira Certificates. 

17.2 Holders of Type Examination Certificates are required to comply with the production control 

requirements defined in Article 8 of directive 94/9/EC. 

17.3 The switches incorporated in the PA option shall be suitably certified for Category 2. 









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Page 5 of 7 

Form 9400 Issue1 

Form 9400 Issue1

Certificate Annexe 

Certificate Number: Sira 01ATEX1295X 

CERTIFICATION 

Equipment: Purge Controllers 

Sub-MiniPurge, MiniPurge, Super-MiniPurge, 


CERTIFICATION 

Applicant: EXPO Technologies Limited 

SCHEDULE 

Issue 0 (The drawings associated with this issue were replaced by those listed in Issue 4) 


Issue 7 

Number Sheet Rev. Date Description 

SD7281 1 to 4 3 02 Jul 02 MiniPurge ATEX Certification Labelling 

SD7282 1 to 2 2 21 May 01 MiniPurge ATEX Certification Type Numbering Scheme 

EP/99-2-17 1 of 1 1 21 Sep 00 MiniPurge, Continuous Flow with /HP Sensor –Schematic diagram 

EP99-7-7 1 of 1 1 21 Sep 00 RLV, outlet orifice 

EP99-7-9 1 of 1 1 21 Sep 00 Outlet Valve Control Circuit Diagram 

17.4 The following routine tests shall be performed by the manufacturer: 

Verification of Minimum Overpressure Cut Off 

An overpressure loss shall be simulated whilst the MiniPurge Control Unit is cycling, it shall be verified 

that the controller provides the appropriate output and resets. 


Verification of Purge Failure Protection 


SD7448 1 of 1 3 22 March 04 Low Temperature Housing - General Arrangement 

A purge failure shall be simulated whilst the MiniPurge Control Unit is cycling, it shall be verified that 

the controller provides the appropriate output and resets. 


Verification of Air Supply Failure Protection 


SD7281* 1 to 5 4 17 Dec 03 Certification label 

SD7449 1 of 1 1 18 Dec 03 Low temperature housing wiring certification drawing. 

* Modified by Sira 30 September 2004 

An air supply failure shall be simulated whilst the MiniPurge Control Unit is cycling, it shall be verified 

that the controller provides the appropriate output and resets. 


Verification of Purging Overpressure protection 

Where the HP is specified an overpressure shall be simulated whilst the MiniPurge Control Unit is 

cycling, it shall be verified that the controller provides the appropriate output and resets. 


SD7281 1 to 5 5 30 Aug 06 Certification label 

Issue 4 


EP99-3-1 1 of 1 02 15 Mar 07 Minipurge Control Unit – General Assembly 

EP99-2-1 1 of 1 03 09 Jul 07 Schematic - Type x Leakage Compensation 

EP99-2-3 1 of 1 02 15 Mar 07 Sequence Diagram - Type x Leakage Compensation 

EP99-2-2 1 of 1 02 15 Mar 07 Schematic - Type x Continuous Flow 

EP99-2-7 1 of 1 02 15 Mar 07 Schematic – Separate Supply and Mechanical Timer 

EP99-2-8 1 of 1 02 15 Mar 07 Schematic – Delay Before Trip and On/Off 

EP99-2-9 1 of 1 02 15 Mar 07 Schematic – Twin Output and Manual Override 

EP99-2-10 1 of 1 03 15 Mar 07 Schematic – Pressure Control Leakage Compensation 

EP99-2-11 1 of 1 03 15 Mar 07 Internal “IS” Switches 

EP99-2-12 1 of 1 02 15 Mar 07 Schematic – Containment System and Secondary pressurisation 

EP99-2-14 1 of 1 02 15 Mar 07 Schematic – Continuous Flow with 2 Flow Rates 

EP99-2-17 1 of 1 02 15 Mar 07 Schematic – Continuous Flow with High Pressure 

EP99-2-16 1 of 1 02 15 Mar 07 Schematic – Outlet Valve Control 

SD7533 1 of 1 01 15 Mar 07 Schematic – Dust Protection 

SD7535 1 of 1 01 15 Mar 07 Spark Arrestor 

SD7536 1 of 1 01 18 Apr 07 Differential Flow Monitor 

SD7538 1 of 1 01 27 Mar 07 Continuous Flow Outlet Orifice 

SD7449 1 of 1 02 15 Mar 07 Wiring Diagram – Low temperature 

SD7500 1 of 1 01 25 Apr 07 Outlet Orifice Closing Device 

SD7448 1 of 1 04 15 Mar 07 Low Temperature Housing 

SD7281 1 to 2 06 20 Feb 07 Certification Label Details 

SD7282 1 to 2 03 20 Feb 07 MiniPurge Data Sheet 

17.5 The products covered by this certificate incorporate previously certified devices, it is therefore the 

responsibility of the manufacturer to continually monitor the status of the certification associated with 

these devices, and the manufacturer shall inform Sira of any modifications of the devices that may 

impinge upon the explosion safety design of the products. 

17.6 The certification code that is appropriate to Purge Controllers low temperature version shall appear in 

the product marking applied to outer stainless steel enclosure. 

17.7 The Purge Controllers: Sub-MiniPurge, MiniPurge, Super-MiniPurge, Super-MiniPurge 

1800/3500/7000/7000X shall not be marked as suitable for use in explosive dust atmospheres when a 

non-metallic or painted housing is used. 









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Page 7 of 7 

Form 9400 Issue 1 

Form 9400 Issue1

Certificate Annexe 

Certificate Number: Sira 01ATEX1295X 

CERTIFICATION 

Equipment: Purge Controllers 

Sub-MiniPurge, MiniPurge, Super-MiniPurge, 


Applicant: EXPO Technologies Limited 


SD7537 1 to 3 01 20 Feb 07 Fault Evaluation 

EP99-7-9 1 of 2 02 15 Mar 07 Outlet Valve Circuit N/O 

EP99-7-9 2 of 2 01 15 Mar 07 Outlet Control Valve N/C 

SD7531 1 of 1 02 09 Jul 07 Schematic – Type Z or Y leakage compensation 

SD7532 1 of 1 01 15 Mar 07 Schematic Type Z or Y Continuous Flow 

EP99-2-4 1 of 1 02 15 Mar 07 Sequence Diagram – Type X Continuous Flow 

EP99-2-5 1 of 1 02 15 Mar 07 Schematic – Alarm only and Alarm Action Selector 

EP99-2-6 1 of 1 02 15 Mar 07 Schematic – Door Switch Active Alarm and Alarm Cancel 

SD7555 1 to 4 01 05 Jul 07 RLV Configurations 

SD7556 1 of 2 01 09 Jul 07 Alternative Z&Y LC System 

SD7556 2 of 2 01 09 Jul 07 Alternative Z&Y LC System 

Issue 5 

Number Sheets Rev. Date (Sira stamp) Description 

SD7281 1 to 2 7 12 Feb 09 Minipurge ATEX/IECEx Certification Label 

SD7448 1 of 1 05 12 Feb 09 Minipurge Low temperature Housing 

Issue 6 


SD7281 1 to 2 8 23 Dec 10 Minipurge ATEX/IECEx Certification Label 

SD7282 1 to 2 4 21 Dec 10 MiniPurge Data Sheet 

SD7913 1 of 1 2 21 Dec 10 MiniPurge electronic timer 

SD7914 1 of 1 2 21 Dec 10 MiniPurge HP sensor 

Issue 7 


SD7448 1 of 1 6 23 Nov 11 Minipurge Low Temperature Housing 

SD7282 1 & 2 5 23 Nov 11 Minipurge Data Sheets 

SD7281 1 to 3 9 23 Nov 11 Minipurge ATEX/IECEx Certification Label 

SD7533 1 of 1 2 23 Nov 11 Minipurge Dust Protection Schematic 





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Page 2 of 2 

Form 9400 Issue 1

® 

File E190061 Vol 1 Issued 1999-07-23 

Revised 2003-05-08 

® 

FOLLOW-UP SERVICE PROCEDURE 

(TYPE R) 

PURGING AND PRESSURIZING CONTROLS AND 

ACCESSORIES FOR USE IN HAZARDOUS LOCATIONS 

(RFPW,RFPW7) 

Manufacturer: EXPO TECHNOLOGIES LIMITED 

(466459-001) SUMMER RD 

THAMES DITTON 

SURREY 

KT7 0RH ENGLAND UNITED KINGDOM 

Applicant: SAME AS MANUFACTURER 

(466459-001) 

Classified Company: SAME AS MANUFACTURER 

(466459-001) 

This Procedure authorizes the above Manufacturer to use the marking specified by 

Underwriters Laboratories Inc. only on products covered by this Procedure, 

in accordance with the applicable Follow-Up Service Agreement. 

333 Pfingsten Road 

Northbrook, Illinois 60062-2096 

United States Country Code(1) 

(847) 272-8800 

FAX No. (847) 272-8129 

http://www.ul.com 

The prescribed Mark or Marking shall be used only at the above manufacturing location 

on such products which comply with this Procedure and any other applicable 

requirements. 

The Procedure contains information for the use of the above named Manufacturer and 

representatives of Underwriters Laboratories Inc. and is not to be used for any other 

purpose. It is lent to the Manufacturer with the understanding that it is not to 

be copied, either wholly or in part, and that it will be returned to Underwriters 

Laboratories Inc. upon request. 

This PROCEDURE, and any subsequent revisions, is the property of UNDERWRITERS 

LABORATORIES INC. and is not transferable. 

A 

UNDERWRITERS LABORATORIES INC. 

A.W. Schaefer 

Vice President and General Manager 

US and Canadian Operations 

A not-for-profit organization 

dedicated to public safety and 

committed to quality service

MiniPurge Interface Unit MIU/e 

User Instruction Manual 

Manufacturer: Expo Technologies Ltd, Unit 2 The Summit, Sunbury-on-Thames. Uk 

Model Type & Rating: MIU/e1 MIU/e2 MIU/e1/MO 

400V / 7A 400V / 7A 400 V / 6A 

Certificates: 

Hazardous Area Marking 

Code: 

APPLICATION SUITABILITY 

The MiniPurge Interface Units – MIU/e are certified for use in Hazardous Areas where the Hazardous Area is nonmining 

(i.e. above ground) and the hazard is caused by flammable gasses or vapours. 

The systems may be used in ATEX/IECEx Gas Zones 1 & 2, Gas Groups IIA, IIB & IIC and in Dust Zones 21 & 22, 

Dust Groups IIIA, IIIB & IIIC. 

The following materials are used in the construction of MIU/e: Stainless Steel, Steel, Brass, Copper, Polyamide, 

Silicone. If substances that will adversely affect any of these materials are present in the surrounding environment, 

please consult Expo Technologies for further guidance. This equipment is designed for use under normal industrial 

conditions of ambient temperature, humidity and vibration. Please consult Expo Technologies before installing this 

equipment in conditions that may cause stresses beyond normal industrial conditions. 

WARNING - Only install, commission, inspect, maintain or fault find when safe to do so. 

INSTALLATION 

The MIU/e shall be installed in accordance with relevant standards, such as EN 60079-14 and any local codes of 

practice that are in force. Cable glands or other cable entry devices shall be appropriately certified and suitable for 

the cable and the conditions of use and be installed in accordance with the manufacturer’s instructions. 

The MIU/e shall be connected to the Purge and Pressurization system in accordance with the instructions given in 

the handbook supplied with the pressurization system. 

The external earth connection of the MIU/e shall be connected to earth using minimum 4mm 2 conductor. 

TERMINALS 

MIU/e may be fitted with a combination of: 

WDU2.5 terminals certified to KEMA 98ATEX1683U & IECEx ULD05.0008U 

SAK2.5 terminals certified to KEMA 98ATEX1798U & IECEx KEM06.0014U 

WPE2.5 Earth terminals certified to KEMA 98ATEX1683U & IECEx ULD05.0008U 

For all type of terminals: 

Tightening torque range: 0.4 to 0.8 Nm (WDU & WPE) & 0.4 to 0.6 Nm (SAK) 

Conductor cross section maximum 2.5 mm 2 , minimum 1.5 mm 2 

Type of connection is screwed - Solid copper conductors to be used. 

Stripping length shall be 10 mm. 

Only one conductor is allowed at each side of a terminal. Multiple conductors shall be crimped together before 

screwed into the terminal. 

Maximum number of terminals: 

For Model MIU/e1 – Up to 18 current carrying terminals 

For Model MIU/e2 – Up to 33 current carrying terminals 

For Model MIU/e1/MO – Up to 13 current carrying terminals 

IECEx ITS10.0003X ITS 10ATEX37092X TUV 12.1463 

Ex e IIC T5 Gb 

Ex tb IIIC T100°C Db IP66 

Tamb -20°C to +55°C 

II 2 G D 


Ex tb IIIC T100°C Db IP66 



Ex tb IIIC T100º Db IP66 


COMMISSIONING 

The installation of the cable glands, electrical and earth connections shall be inspected for correct installation 

before the unit is put into service. The lid shall be correctly fitted. 

MAINTENANCE 

The condition of enclosure and associated cable glands shall be inspected for damage every six months. The 

terminals shall be inspected for tightness and gaskets inspected for damage. 

FAULT FINDING 

When wiring or signal fault occurs, check each terminated wire, terminals for tightness and gaskets for damage. 

External faults such as broken switches within the Control Unit may also require investigation. 

ML358 v5 Page 1 of 1 06-Nov-12

EC-Declaration of 

Conformity 

S:\Files\QA\CERTS\C-OF-C\Minipurge CE SC004 Issue4.doc 

With 

European 

Directives 

Expo Technologies Ltd 

Summer Road 

Thames Ditton KT7 0RH UK 

Expo Technologies Ltd 

declares that 

Purge Controllers Type “MiniPurge” certified under 

EC Type Examination Certificate SIRA 01ATEX1295X 

are manufactured in conformity with the following 

European Directives and standards: 

Electromagnetic Compatibility Directive 2004/108/EG 

MiniPurge Systems with a /PO suffix in the type number are non-electrical and are outside 

the scope of the EMC Directive. 

MiniPurge Systems with suffices /PA or /IS incorporate one or more volt-free (“dry”) 

contacts which work in circuits specified by others. In normal operation these circuits are 

“benign” and no CE mark is appropriate. 

MiniPurge Systems with Electronic Timer (Option /ET) are designed to conform to the 

EMC Directive, in compliance with EN 61000-6-4:2007 and EN 61000-6-2:2005 (Intertek 

Report EM10048000). 

Low Voltage Directive 2006/95/EC 

MiniPurge systems are intended to be used in Hazardous Areas (Explosive Atmospheres) 

and are therefore excluded from the Low Voltage Directive. 

ATEX Directive 94/9/EC 

MiniPurge systems are designed to conform to the ATEX Directive, in compliance with: 

EN 60079-0 : 2009 EN 60079-2 : 2007 

EN 61241-0 : 2006 EN 61241-4 : 2006 

Pressure Equipment Directive 97/23/EC 

Signed Date 27/01/2011 

Managing Director Confidential Assessment file reference SC004

Expo Technologies Ltd., Tel + 44 (0) 20 8398 8011 

Unit 2, The Summit, Fax + 44 (0) 20 8398 8014 

Hanworth Road, E-mail: sales@expoworldwide.com 

Sunbury-On-Thames, 

TW16 5DB 

Expo Technologies Inc., Tel: +1 888-NFPA-496 

9140 Ravenna Road Unit #3, Tel: +1 (440) 247 5314 

Twinsburg Fax: +1 (330) 487 0611 

OH 44087 E-mail: sales.na@expoworldwide.com 

USA 

www.expoworldwide.com

Mini-X-Purge Size 1 Manual ML 442 - Expo Technologies

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