Carbon dioxide CO2: Explosive decompression – elastomeric seals during decoupling

What causes explosive decompression in elastomers?

For a long time, WALTHER-PRÄZISION has been working on the physical mechanism that is partly decisive for the service life of quick couplings. When selecting the O-rings of our quick coupling valves, not only the pressure and temperature, but also the pressurisation time / pressure relief time of the acting gas are not just important, they also have a decisive influence on service life:

Depending on how long an O-ring is exposed to CO2, it can penetrate the O-ring. If decoupling (*For gaseous substances it is mandatory to decouple without pressure!) is now performed and CO2 molecules were previously able to penetrate the O-ring, the CO2 now in the O-ring expands correspondingly fast when the pressure is relieved quickly without an adequate decompression phase. This physical process leads to extreme swelling or bursting (damage pattern similar to explosion) and thus to the destruction of the O-ring (= explosive decompression).

As the required decompression time/holding time strongly depends on the combination of the boundary conditions (CO2 concentration, O-ring dimension, design conditions, time, pressure), a test must be conducted in each individual case.

Please do not hesitate to contact us, we would be pleased to advise you and work together with you to select the appropriate quick coupling with the suitable elastomers.