An Overview On How To Select The Best Material In Viton O-Rings For Specific Applications
Elastomer O-ring seals are mostly used to provide demountable vacuum seals. The appropriate selection of material, installation, and handling are vital to an effective vacuum design. The sealing integrity of vacuum systems, undoubtedly, is a critical component of vacuum technology, and demountable seals are an important element. A demountable seal can be taken as any seal that is capable of being opened or closed contrary to permanent seals, like, welded or brazed joints, which incorporates critical parts, for example, flanges and valves.
Viton O-Rings Has Advantage Over Metal Seals
Any deliberation and reflection of these components lead us directly and inflexibly to the topic of gaskets and gasket materials, which can be easily distinguished into two primary groups — metal and elastomer. Metal seals are naturally cleaner and more solid, however, their use has the overall disadvantage of being costly and more time and labor-intensive than elastomer gaskets, like Viton O-Rings. Subsequently, elastomer seals are used whenever possible in most applications, and they are typically applied in the form of O-rings.
Defining O-Ring Materials Is Tedious
Elastomers, all in all, are organic polymers that show an elastic resilience that lets them deform marginally when under compression, however with enough elasticity to prevent permanently deforming or flowing. In an O-ring seal, the material can create a seal between two smooth surfaces, for example, flanges, by flowing a little into infinitesimal imperfections in the flange and still retain an internally stored force, to maintain the seal when opened and closed over and over. It is helpful to imagine a “rubbery” material contrary to materials, like, Teflon that will flow into some other shape upon compression and maintain that shape when the compressive force is removed.
Ask any custom O-ring supplier and he will say that O-ring materials are hard to define, since they are not clearly defined chemical compounds. To make it more confusing, there are various potential varieties that are experienced within a single material category.
To put it simply, they are “compounded” of various component materials, for example, the basic resin, fillers to encourage resilience, plasticizers, and curing agents. Within a specific generic category, the actual compounding and the molding processes will have distinct variations and all of these versions will be taken as proprietary. For instance, the filler may be carbon black or it perhaps will be diatomaceous earth. What this indicates is that any properties of the materials will have a wide range of versions and that it’s important to contemplate this when using them or designing them into vacuum systems and processes.
Try To Find Best Material For Specific Applications
The most frequently applied generic categories of O-ring materials are nitrile, like, buna-N, butyl, fluoroelastomers, like, Viton and Fluorel, and perfluoro elastomers, like, Chemraz and Kalrez. Each of these categories has broadly variable vacuum related properties that make it tricky to make a generalized opinion regarding which is the best material. Rather, it is critical to try and find the best material for a specific application, where the specific properties of the elastomer will make it a better choice.
Bottom Line
The current vacuum processes usually involve the use of specific gases that can attack or, at least, alter the properties of the elastomer seals. In other words, no specific compound will be best for all applications. Rather, it’s important to use the chemical resistance tables collected from a Metric O-Ring supplier to determine the best material. Simultaneously, it’s also important to compare various vacuum properties that may impact the application. By and large, though, perfluoro elastomers turn out to be most resistant to chemical attack.
