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Simplifying Complexity. Delivering Safety.
Simplifying Complexity.
Delivering Safety.

Purge & Pressurization systems for large Ex p electric motors & generators

With more than 7,500 purge and pressurization systems supplied for large electric motors and generators, Expo is the world’s most experienced designer and manufacturer. As the leading designer and manufacturer of systems, we have the right solution for your machine.

Download our brochure to find out more.

Use the table below to choose a system suitable for your application

Purge gas flowrate /
Expo system size
–20°C to +55°C
–60°C to +55°C
–20°C to +60°C
Up to 1500 Nl/min
/ Size 3
Up to 6000 Nl/min
/ Size 5
Up to 14,000 Nl/min
/ Size 7

Special motor purge systems

Expo can design and build custom motor purge systems, for instance for very large motors where high flow rates are required Please call +44 (0) 20 8398 8011 to speak to one of our purge and pressurization experts or contact us.

Range Overview

Expo’s purge and pressurization  control units will enable your motors & generators to meet:

  • ATEX & IECEx requirements for Zone 1 & 2 and Zone 21 & 22;
  • NPFA requirements for Class I Div 1 & 2/ Zone 1 & 2. Class II Div 1 & 2 / Zone 21 / Zone 22
  • KOSHA, EAC and INMETRO certification

Typical system features:

  • CLAPS (Closed Loop Automatic Pressurization System) - eliminates spurious motor trips due to localised changes in enclosure pressure
  • Purge flow rates for all motor sizes range from 500 Nl/min to 14000 Nl/min.
  • Standard ambient temperature range -20°C to +55°C. Low temperature option to -60°C, high temperature option to +60°C for most extreme locations.
  • Purge timer: accurate and repeatable purge times up to 99 minutes. Battery or EPPS (electro-pneumatic power supply) options
  • 316L Stainless Steel enclosure for long service life in harsh conditions
  • Ex e junction box & terminals for system status & alarms. Optional Ex i, Ex d junction boxes.


  • Proven solutions for Ex p machines
  • Largest, most global, installed base
  • Systems for very large machines
  • Options for harsh environments

Configure your product

Use our product configurator tool to build a system to your exact specification.