What are O Rings?
You could argue that the o-ring is a bit of a "living fossil" in terms of manufacturing components. They were first brought to market way back at the dawn of the 20th century - and yet, for all their absolute simplicity and the very basic nature of the role they perform, they're still incredibly widely used today.
Furthermore, as fast as the worlds of engineering, manufacturing and component design have changed in the intervening 120+ years, o-rings have stayed more or less identical in both form and function. Some of the materials used in the manufacture of o-rings have of course become more high-tech over time, but essentially o-rings remain a beautifully straightforward and reliable solution to a problem that was first brought up more than a century ago.
How do O-ring seals work?
Whether sold individually, in large wholesale batches or - as is increasingly common - as part of a highly flexible range of o-ring kits, the basic form and role of o-rings are generally the same across the board.
Their name, as implied, simply refers to a classic doughnut or torus shape, and they exist purely to create a better, more leak-proof seal between two other components, with the aim usually being to prevent the unwanted escape of gases or liquids. In this sense, they're effectively a type of gasket - the main difference being that o-rings are more commonly used in very high-pressure environments, where a normal cork, paper or rubber gasket would likely be prone to failure.
In very basic terms, o-ring seals work by sitting in a groove or channel between two surfaces/components that are going to be mated or pushed together. The o-ring, generally made of some form of elastomer, sits in the join between these two parts, and becomes compressed in order to help form a tight seal. The more internal pressure is applied to this join, the more the o-ring is distorted inside its groove, which can improve its overall sealing force up to a point - but beyond a certain pressure, or under more dynamic workloads, this can cause failure of the seal. It's important to get the balance right between o-ring material, size and working environment in order to fulfil the role you need it to perform.
Compared with O rings, sometimes gasket rings are more suitable. When deciding whether a gasket or O-ring is best for your application, consider the environment and function of the seal. When choosing the best seal, look for features such as shape, temperature, and pressure.
When a non-circular joint requires a good Sealing Ring, an O-ring would be difficult to use because of its round shape. Gaskets can be customized to almost any shape, allowing them to work as a seal for a larger variety of applications. The operating temperature of equipment will determine the best material to use for manufacturing the O-ring or gasket. While both can withstand a wide range of temperatures, gaskets are best for extreme temperature situations. However, O-rings perform better than gaskets in applications with extreme pressure.