Expo Technologies Principle of Operation Expo Technologies Ltd Sunbury-on-Thames, England Expo Technologies, Inc Twinsburg OH, USA Representatives & Distributors World Wide Your Support Network Flow Sensor Purge Outlet Pressure Sensor Purge Inlet Main Factory Location Minimum Pressures Purge Outlet Purge Flow Sensor FE Pressurized Enclosure Standard Minimum Pressure IEC60079-2: 2007 (Zone 1) 50 Pa / 0.5 mbar (0.2 WC) Heathrow Sunbury City Low Pressure Sensor PE IEC60079-2: 2007 (Zone 2) 25 Pa / 0.25 mbar (0.1 WC) Australia AS2380 Pt 4 50 Pa / 0.5 mbar (0.2 WC) Europe EN 50016 50 Pa / 0.5 mbar (0.2 WC) USA NFPA 496 25 Pa/o.25 mbar (0.1 WC) Measured at the eye of the fan Inlet for Protective Gas Gatwick Applications suitable for Exp Terminology Control Panels Switchgear Motors Generators Analysers Rooms/Buildings Static Pressurization Enclosure is purged & pressurized but sealed Leakage Compensation (LC) Enclosure is purge & pressurized Switches to small flow (tops up any leakages) Continuous Flow (CF) Enclosure is purged & pressurized Purge flow continues (dilutes internal release)
Basic Build Requirements Motor Purge systems Flow meter monitors purge (and subsequent) flow rate no over-ride Pressure sensor 1 monitors minimum required overpressure Pressure sensor 2 protection against excessive overpressure Alarm / Isolation of electrical equipment if overpressure falls below 0.5mb (Zone 1) System types Purge Time Equipment being protected Non-Ex Equipment Ex-Equipment (Ex n / mb) Zone 1 Division 1 Auto-Disconnect Auto-Timer Ex px X-Purge Alarm Only Manual Ex py Y-Purge Zone 2 Division 2 Alarm Only Manual Ex pz Z-Purge IEC Standard Equal to 5x enclosure volume NFPA Standard Equal to 4x enclosure volume 10x enclosure + rotor volume (for motors) Practical limit (user-defined?) 60 minutes for large motors & compressors 30 minutes for cabinets 10 minutes for portable equipment Custom Enclosures Pneumatic Timer Based on R C network R = pneumatic restrictor C = pneumatic reservoir C1 C2 C3 R
Electronic Timer Accurate & Repeatable 1 to 99min (-0/+3 secs) Intrinsically Safe Ex ia IIC T6 Field-replaceable battery 3 year service life 10 year storage life Global Approvals ATEX / IECEx / FM / UL (pending) LED Purge Progress Indicator Typical Settings Pressure Point Pressure Leakage Nl/min Minimum Acceptable Pressure 150Pa, 1.5mbarg Normal Working Pressure 1kPa, 10mbarg Client continuous air usage Relief Valve Lift-off Pressure 3.0kPa, 30mbarg Clients air usage during the purge period Test Pressure (RLV x 1.5) 4.5kPa, 45mbarg Must hold the pressure for 2 minutes without distortion Witnessed Purge Test required for every motor to ensure compliance with the first motor tested / certified Motor Purge Systems Typical Motor Purge System D758 Relief Valve Exe Junction Box Motor Systems G.A. Typical Internal CLAPS: Closed Loop Automatic Pressurization System
Typical Alarms Loss of Pressurization (Alarm/Shutdown) Intermediate Pressure (Alarm) Permissive Contact (Shutdown) Typical Installation Drillers Console 1ZLC/bp/IS Electronic Options: Ex e or Ex i circuits Pneumatic Options: Pushrod into Ex d box Expo Motor Systems Coding 1ZLC/pm/IS Hazardous Area Application X: covers dust and gas protection and has a timer Y: only covers dust protection Z: covers dust and gas protection but is manually timed Housing ss: stainless steel box pm: panel mount bp: back plate nm: non metallic co: chassis only Standard Options OV: Outlet Valve AO: Alarm Only MO: Manual Override Non standard output options AA: Active alarm output fitted AC: Alarm cancellation circuit AS: Alarm Action on pressure of flow failure selector valve DS: Door Switch Power interlock fitted DT: Delayed Trip after pressure or flow failure FM: Flow Meter(s) fitted MT: Mechanical Timer OA: On/Off switch controlling protective gas or logic supply OB: On/Off switch controlling logic supply only OC: On/Off switch controlling protective gas only PC: PE pressure control leakage compensation valve SS: Separate supply for protective gas and logic air TW: Twin (or more) outputs for PEs purged in parallel. 5 X LC / ss / ET / OV / PA / PC / D758 System Size Each number represents a certain amount of air flow (NI/min) 3: 500-1500 5: 2000-6000 7: 7000-14000 Purge Method LC: (Leakage Compensation) CF: (Continuous Flow) ET: electronic timer. If it uses a pneumatic timer then this block is not included Standard Outputs PA: Power Alarm PO: Pneumatic Output IS: Intrinsically Safe Model variant Many types available, some OEM specific, some general Advantages of Ex p for motors Custom Enclosures - internal Only practical solution for high power units Clean air purge removes environmental contaminants Easier to achieve IIC compliance High level of security & confidence Monitored systems External alarms Power interlock
Custom enclosure - external Minimum requirements Overpressure test 1.5x manufacturers rating (typically 30 50mbar) Doors to be opened with tool (Zone 1) IP4X (Zone 1) 7Nm (4Nm on windows) UV resistance test Standard cabinets pass the above but leak! Typical enclosure systems Custom Cabinets Mini-X-Purge Interface Box Mini-Y-Purge Empty cabinet, Populated cabinet, Manufactured with Exp system Expo-inspected, ATEX or IECEx certified assembly Purge system selection Custom Enclosures Hazardous Area standards ATEX / IECEx / NEC / CSA / INMETRO Zone or Division X-purge or Z-purge Enclosure contents Ex ratings, power, T rating Enclosure Size / Purge Time Determines required air flow capacity Zone 1 (ATEX Cat 2) Pressurized Enclosures Expo PE2 Increased Safety Expo PE2E Zone 2 (ATEX Cat 3) Pressurized Enclosures Expo PE3 Increased Safety Expo PE3E
Custom Enclosures - Zone 1 (ATEX Cat 2) Expo-Intertek Schedule of Limitations 3 Pressurized Enclosures PE2 Expo construct OR verify clients assembly Schedule of Limitations GA drawings & Component List 3 rd Party Certificate in Expo name: IECEx: ITS 08.0044X ATEX: ITS10ATEX16944X -20 to +55 C Ex px IIC T4 Gb Ex p IIIC T135 C Heat Dissipation Batteries or Cells Fans Two temperature limiting devices must be used (one can be used to initiate a cooling system). The following approved batteries are allowed: CR2032 (VARTA or Panasonic) CR½ AA (VARTA or Sonnenschein) SL-340 (Tadiran or Sonnenschein) ** Non-approved batteries require an Expo Battery Test Maximum airflow permitted: 400 litres/sec (14.125 ft 3 /sec) Inlet Position > 200 mm (7.78 ) from air leakage points, e.g. door gaskets or access plate gaskets. * Can be exceeded: requires witnessed purge test Expo-Intertek Schedule of Limitations 1 Expo-Intertek Schedule of Limitations 4 Maximum Size * Purge Time Layout * 2100 mm (82.68 ) H x 1800 mm (70.87 ) W x 1000 mm (39.37 ) D Maximum volume = 3780 Litres Purge Time must reflect 10 volume changes and be between 10 and 30 minutes 30% minimum free space, in any cross section of any plane of the enclosure. Optical Devices Permitted Thru-Wall Components Low power communication devices are allowed. Devices or components mounted through the enclosure wall must have a suitable IP rating for the enclosure and must either be metallic (or if non-metallic, must be Ex rated - demonstrates compliance with UV & Impact specification). Cable Glands, Conduits and Sealing Systems shall be Ex-certified and suitable for use with the cable type and in the required Hazardous Location. * Can be exceeded: requires witnessed purge test * Can be exceeded: requires witnessed purge test Expo-Intertek Schedule of Limitations 2 Expo-Intertek Schedule of Limitations 5 Ventilation of Internal Items * Internal closed items require minimum ventilation holes of 1cm²/litre to avoid potential trapped gas. If necessary, increase existing holes to suit or make new/additional holes (min. size 28.2mm 2 or 0.043in 2 ) Closed items need ventilation distributed equally at the top and bottom surfaces. Isolation of Electrical Inputs to the Enclosure ALL electrical supplies (power & signals) that enter the enclosure NOT individually protected by another explosion protection technique MUST be automatically isolated following the ALARM signal of the Expo Purge Control system. Hermetically sealed or potted devices. Internal devices with surface temperature above T4 (135 ºC) Permitted Closed Items Allowed if total volume of such sealed items < 1% of the internal free volume of the enclosure, and: - the item does not contain any potential source of ignition, or - the item is Ex d, Ex e (no batteries), Ex i, Ex m or Ex n certified Hot Internal Components must be declared, and extra precautions identified and specified. Examples are: filament lamps, power semiconductors, thyristors, heaters, power resistors, etc. * Can be exceeded: requires witnessed purge test
Achievable certification Extra considerations Hazardous Area Classification Ex px IIC T4 Maximum range for T amb = -20ºC to +55ºC NOTE: fitted certified apparatus with more restrictive classifications (T rating and/or Gas Group) will reduce the overall classification of the PE, and the supplied labelling will be modified to suit. Internal source of release Notified Body test Nitrogen purge Most Ex HMI s will fail over-pressure test Fit into separate inset housing, non-exp Ex equipment must match overall approval ATEX devices must be ATEX marked IECEx devices must be IECEx marked What we need Purge Flow Monitoring Orifice Plate Bill of Materials (BoM) General Assembly Drawings (GA) Circuit Schematics Power & Signal Isolation design Data Sheets & Certificates for hazardous area rated equipment and devices (changeable) What you get Z-Purge CF: Control Unit, Relief Valve Expo guidance on equipment selection Expo test/verification of content Expo Declaration of Conformity IECEx ATEX Enclosure labels Instruction Manual SS PM BP Boxed, top or side mounting Panel mounting (inset) Back-plane CF systems include spark arrestor
Z-Purge LC: Control Unit, Relief Valve X-Purge Systems SS PM BP Boxed, top or side mounting Panel mounting (inset) Back-plane Purge in Progress indicator Spark Arrestor flow capacity X-Purge, direct top mounting Enclosure Volume O/P No. ft 3 (4x volume) m 3 (5x volume) 1 3.0 0.06 2 8.3 0.15 3 10.5 0.24 4 17.2 0.39 5 24 0.54 6 36 0.81 7 48 1.08 8 60 1.35 Z-Purge Multiple Enclosures Zone 2 / Div 2 use Versions: CF Continuous Flow LC Leakage Compensation Manual operation Manual timing Alarm on loss of pressurization Local indicator Volt-free contact (for wiring by others)
HMI without Ex approval Window to meet impact test Push-rods operate buttons No product modification SmartPurge accessories I.S. solenoid valve for air inlet Remote panel (50m max) Manual override key switch SP2- SIU SP2- DV SP2- RP SP2- CF SmartPurge 316 SST Enclosure Pushbuttons Spark Arrestor IECEx / ATEX Ex [px] IIC T4/T6-20 to +60 DegC Ex p systems Simple in principle Solves unique and difficult problems Allows manufacturers to extend their market application with limited outlay Integrates other protection concepts easily EXPO: Solution Provider SmartPurge System Controls up to 540 l/min Switches up to 6A Purge up to 99min Delay up to 99min