O-rings are the most commonly used sealing component in many industries and are present in many everyday items. However, it can be extremely expensive and damaging to the application when they fail, especially in industries such as the automotive, food and dairy, medical and oil and gas industries.
O-rings are typically available in a wide range of elastomer materials to suit specific environments, such as high and low temperatures, high pressure and aggressive chemical media.
There are many reasons why o-rings can fail in applications, but it can be avoided with proper care, advice and correct installation.
Here’s a list of the most common reasons o-rings fail:
Abrasion - this is often found in dynamic applications and abrasion will occur from repetitive contact between the o-ring and the outer surface resulting in excessive friction
Ensuring the correct amount of lubrication is applied will ensure that the o-ring operates without any issues. Higher quality elastomer materials will have improved abrasion resistance but will still need to have proper lubrication.
Chemical Attack - some chemicals react to certain elastomer materials which often causes the o-ring to become a hard and brittle material, with the reduced ability to provide a reaction force. In some instances, the cross-link density can reduce causing the o-ring to lose its original shape and integrity.
Getting the right high-quality o-ring elastomer for your application is crucial from the beginning to ensure that the material is right for the environment it is operating in. Both operating temperatures and stress levels must be factored in.
Compression - If the incorrect elastomer material has been selected, damage can occur both physically and chemically to the o-ring in harsh environments. The damage could cause the o-ring to lose its elasticity and ability to return to its normal shape.
Extrusion and nibbling - exposure to high-pressure gas at elevated temperatures for a prolonged period of time can cause the polymer to absorb the gas. This leads to the elastomer material to form microbubbles in the form of internal gas which decreases the effectiveness of the seal.
Installation Damage - Installation damage can be a wide range of damaging factors that cause o-rings to fail. For example, a few common failures are caused by twisted or improperly lubricated seals.
This is where expert advice is always important for optimum performance as the costs can build up if the wrong seal is used or if it has been installed incorrectly. So it is important to know what to look for in your o-ring supplier.
This is not an extensive list of reasons why o-rings tend to fail but best practice to avoid failure is to seek expert advice from the initial enquiry, right through to the installation of the seal.
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