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Nitrogen Buffer Systems for Gas Compressors

Pressurisation systems to limit flammable gas emissions from reciprocating compressors


  • Easier compliance with API618
  • Capacity up to 10 dual compartments
  • Stainless steel enclosure construction
  • Optional hazardous area certification

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Reciprocating compressors incorporate pistons and piston rings and, during service life, there is a risk that those seals may allow some gas leakage. Inert gas buffer systems are used to minimise gas leakage, and to dilute and drive any such gases to a common flare or vent stack.

Building on Expo’s expertise in motor purge and pressurisation systems, the Nitrogen Buffer Systems make compliance with API618 straightforward, through the use of a pre-packaged design to suit the number of compartments in the compressor. Our active pressure control stabilises injection rates and minimises the compressed gas leakage, whatever the flare line pressure.

Our systems are highly modular, and up to 10 dual compartment compressor cylinders can be supplied from a single system.




Gas supply
Clean, dry nitrogen 4-10 barg
System capacity
Up to 25 Nl/min per compartment
Maximum flow capacity 500 Nl/min
Temperature range
-20°C to +55°C
Materials of construction
316 stainless steel enclosure
Signal outputs
Optional pressure alarms
Optional pressure transmitters
Optional hazardous area approval