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

High Temperature Motor Purge & Pressurization Systems (Models D670/D770/D870)

IECEx, ATEX & INMETRO Certified Purge and Pressurization Systems for Electrical Machines in High Temperature Environments


  • Certification to +60°C
  • Purge flow capacity between 1,000 and 14,000 Nl/min
  • Stable machine pressure with CLAPS technology
  • Stainless steel enclosure construction

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  • Description
  • Specifications
  • Downloads
  • Certificates
  • 3D Models


Building on the range of motor purge and pressurization systems for standard temperature, Expo have developed special systems for high temperature service as high as +60oC ambient.

The range comprises 3 systems with fow capacities between 1,000 and 14,000 Nl/min.

The systems comprise the Control Unit (CU) and the Relief Valve (RLV). The Control Unit has two compartments – one is insulated and cooled by a thermostatically operated vortex cooler and contains the control logic system, while the other contains the main air control components.  The logic compartment is fitted with an RTD to provide temperature monitoring. The RLV measures purge flow at the outlet and provides over-pressure protection for the machine.

Like all other Expo motor purge systems, these high temperature units incorporate Expo’s Closed Loop Automatic Pressurization System (CLAPS).



Temperature range
Ambient: -20°C to +60°C Purge air: -20°C to +70°C
Purge timer
1-99 minutes
Timer power source
IS (Intrinsically Safe) Battery or Electro-Pneumatic Power Supply (EPPS)
Signal Outputs
Function: Power interlock, low pressure alarm, intermediate pressure alarm, purge in progress (optional)
System variants
D670: Purge flow up to 1,000 Nl/min
D770: Purge flow up to 6,000 Nl/min
D870: Purge flow up to 14,000 Nl/min

* Not all certifications may apply to all system variants. Check the specific Operating & Maintenance Manual for details.