Sometimes the simplest idea can have the biggest impact. So it was with a tiny, circular, rubber seal commonly referred to as the o-ring. This little gasket, designed to prevent the leakage of gas or liquid in machines, would go on to have big implications in the development of machinery of all kinds — from toilets to space ships — it is even credited with helping the US in a time of war. Knowing what o-rings are, their history, composition, and traits, means understanding that there’s an o-ring appropriate for practically any mechanical project, big or small, at home and at work today.
What Is an O-Ring
An o-ring is a small, circular gasket with a round cross-section center used in the groves of mechanical components to prevent the leakage of gas or liquids. The way the o-ring works is beautiful in its simplicity. The gasket fits within or between two components, creates a thin layer of lubrication, and seals the space between components preventing any leakage. That may not sound so special, but the invention of anything using a pump — from the espresso machine to the space shuttle — is due to the functionality of that tiny seal.
History of the O-Ring
Though o-rings were notably present in designs before the official patent in 1937, including Thomas Edison’s 1889 lightbulb, the seal was originally used in the manufacturing of motor vehicle brakes. Unfortunately, patent laws were not stringently followed in this era and Christensen’s design was ripped off and used mercilessly in any product requiring a small rubber gasket, while Christensen received no compensation for his invention. That was until the 1940s when the US government bought the patent outright for the lump sum of $75,000. O-rings were then 100 percent made in the USA to produce tanks, trucks, guns, and machinery to fight the Nazi regime in Europe.
The two basic kinds of o-rings are static and dynamic. Static o-rings are intended to stay fixed in position while dynamic o-rings move. Though the o-ring design is simple, there are important factors to think of when choosing the right one. The first is the composition — what is it made of? One reason why o-rings are so important is because they can be crafted from many different materials, making them applicable in countless machines. The most common materials available for the production of o-rings include nitrile, fluorocarbon, silicone, perfluoroelastomer, ethylene propylene, fluorosilicone, neoprene, ethylene propylene, chloroprene and polyurethane.
Selecting an O-Ring
But the material is not the only important factor. Consider the compressibility of the o-ring — how hard does it need to be? Additionally, what are the operational and environmental conditions the ring will be performing in? Will acids, oils, or steam be present? Lastly, the permeability and abrasiveness of the o-ring material should be evaluated when determining which type to use for your project. The integrity and performance of your project depend on those seals, so choosing the right o-ring for safety and functionality is imperative.
Just like how life is built around a tiny atom, much machinery is built around the tiny o-ring. Available in all sorts of sizes and materials, the o-ring came from humble beginnings in automobile brakes and went on to help the Allied Forces win WWII.
The o-ring has traveled the world, functioned in countless environments, and still shows up in your home today to help assist you in your daily mechanical projects.