ONC StoppersONC Stoppers

ONC - Stoppers for the chemical cleaning of plate heat exchangers

Working in collaboration with EDF, Pronal has developed a stopper system capable of plugging the inlets and outlets of plate heat exchangers during chemical cleaning operations.

Furthermore, the ONC stoppers can be remotely installed in the pipes using a rod and a cradle to prevent the stopper from being damaged by any abrasive surfaces on the plates. They are highly resistant to cleaning fluids. The inflatable stoppers remain completely air/watertight up to a pressure of 3.4 bar. Different dimensions are available: ONC 240, ONC 280 and ONC 380.



  • High chemical compatibility
  • High diametrical dilation


  • High quality
  • Highly resistant to chemical products and temperatures


  • System equipped with a rod and cradle for installation
  • Stopper can be used portably

Detailed information

  • Material: NBR (Nitrile Butadiene Rubber) PMUC-certified
  • Technique: hot vulcanisation in a vacuum autoclave
  • Dimensions: dia. 240, 280 and 380 mm
  • Form: cylindrical
  • Inflation: by air
  • Temperature resistance: -25°C / +100°C
  • Max. inflation pressure: 7 Bar
  • Accessories:
    • Rod
    • Sling
    • Cradle
    • Supply line

You can not find your dimensions

Our design department employs the best project leaders and designers and will be pleased to develop and create a tailor-made product specially for your unique project.


Composition / Advice

Storage advice
Store in its original aluminium case away from light, damp, and temperature variations.
Installation advice
the use of the cradle is recommended during installation to protect the stopper from any sharp edges of the plates.

Standards / regulations

In accordance with the conditions of the Pronal guarantee
Please contact us


Fact Sheets / Business Guides
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