Top 5 Considerations When Choosing an Elastomer for an O-ring

There are several types of elastomer to take into consideration for your o-ring. The most popular are nitrile, propylene, silicone, fluorocarbon, polyacrylate, neoprene, fluorosilicone, aflas, hydrogenated nitrile and butyl. There are positive and negative aspects to all of these elastomers, which can make it difficult to choose the right one for your o-ring. This is why I have set out the top five considerations to take into account when making your decision.

Fluid Compatibility

The job of most seals is to block up fluids and prevent liquid damage. All elastomers can withstand a range of fluids, though some are better at resisting certain fluids than others. Seals made from the wrong elastomers for the required job can become damaged by the type of liquids they are blocking, resulting in either swelling or deterioration.

Differential Pressure Resistance

A seal will most likely function properly when there are equal amounts of pressure being applied to both of its surfaces. When the two pressures are different, the seal is likely to fail, as the higher pressure will extrude it from its groove. This can be avoided by using a harder elastomer, so that the pressure cannot push it around so easily.

o ring

Temperature Capabilities

When it comes to temperature, the elastomer you choose is vitally important. This is because o-rings are needed to perform in both extremely hot and cold climates, meaning that the elastomers used need to be able to withstand those conditions without being damaged or destroyed. For example, an elastomer designed for a hot temperature that is placed in a cold environment can become brittle and crack. Conversely, an elastomer better suited to cold conditions that is placed in a hot environment will lose its effectiveness much quicker than expected, so it will have to be replaced regularly.

Tear Resistance

If seals are used in a process that involves a lot of dynamic movement and action, they should be made from a tear resistant elastomer. If this does not happen, the seal can become cut and torn during the machineries operation. Elastomers that are tough and good for avoiding this wear-and-tear include hydrogenated nitrile, aflas and butyl.

Price

Of course, when buying a product, the price of it is always an important factor and like all other product ranges, the cost of elastomers varies between each one. Nitrile is typically the cheapest of the elastomers, whilst Fluorocarbon and Fluorosilicone can generally be found at the higher end of the price bracket.

This guest blog was brought to you manufacturing guest blogger Kevin Burns. Ke works on behalf of leading <a
href=”http://www.prepol.com/product-range/O-Rings“>O-rings manufacturers Precision polymer Engineering</a>.

Photo source: http://www.flickr.com/photos/attesmythe/2977899493/

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