O-rings and seals: why they leak

Paul Boughton

No matter how well they are made or what precautions you take, all O-rings and seals let liquids and/or greases through - simply because they allow water and hydrocarbon vapours, etc, to permeate through the actual materials from which they are made.

Some materials that you would expect to be good seals - such as cellulose, EVOH, PVOH, actually present almost no barrier to water as a vapourThis causes all sorts of problems for a staggering number of processes, products and production lines - from machines that misfeed, jam or fail, through to products that degrade prematurely. There is no ‘cure’ - but you can reduce the effect by enough to make it stop being a problem.

And that's where Versaperm's latest generation of Seal and O-Ring permeability testers can save the day, with a simple way to test and check products, samples and components with its fast and simple-to-use equipment.

The Versaperm O-Ring and Seal Vapour Transmission meter can take measurements on several items at the same time, sometimes giving a reading in as little as 30 minutes. Accuracies are usually in the PPM (Parts Per Million) range.

Seals and enclosures can be highly sensitive to changes in pressure, temperature and other conditions. Worse still, manufacturing processes such as thermoforming can degrade the performance of materials to a quarter of their original value. Testing is the only way to ensure that a seal is fit-for-purpose and that Quality Control is being maintained.

Versaperm's permeability meters can be configured to detect not only water vapour, but also hydrocarbon vapours, oxygen, CO2 and almost any other vapour.

Recent Issues