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Interesting Facts About O-Rings

Monday, July 23, 2018

Interesting Facts About O-Rings

O-rings are manufactured across the globe and are the most common seals used to contain fluid. They usually consist of a doughnut-shaped ring (the technical term for the shape is a toroid) made from a variety of pliable elastomers such as Neoprene or silicone. O-rings are widely used for sealing joints and connections in hydraulic and pneumatic systems, but their use extends far beyond the industrial industries. Here, we cover the O-ring’s interesting history and their vast range of applications, some that may be quite surprising.


The original U.S. patent for the O-ring belonged to Niels Christensen, an immigrant from Denmark who played with the idea of using rubber rings to seal the air brake system he was designing for streetcars. In 1936, he discovered that if a rubber ring was set in a groove that measured one and a half times the minor radius of the ring, it created the perfect seal for pistons and cylinders. Christensen was awarded his patent in 1939, but during World War II, the US government declared the O-ring a “critical war-related item” and the rights to manufacture them were handed over to many other companies. Christensen received a hefty compensation payment at the time but his heirs continued with litigations, resulting in a further payment from the government in 1971.

Common Applications

In the transportation, aviation and even aerospace industries, O-rings are a critical component for preventing chemical exposure, limiting vibration and protecting occupants from extreme exterior temperatures. In the medical field, syringes, pumps, filtration equipment and various connectors require special FDA-grade O-rings. For food and beverage dispensing, O-rings need to be specially made to the highest sanitary levels. And, of course, in the industrial markets, O-rings are key fixtures in valves, fittings, connectors, gas pumps and storage tanks. These types of O-rings need to be able to withstand extreme temperatures, hazardous chemicals and enormous pressure so they’re usually manufactured from specialised compounds designed for each unique application.

Surprising Applications

You may not have been aware before, but O-rings are used everywhere from your home appliances and office equipment to scuba gear and paintball guns! Some of the most surprising orders come from orthodontists, who use silicone O-rings in dentures to ensure that liquid doesn’t leak into the implants. O-rings are also used in tattoo guns to prevent noisy vibration and steadier operation. In paintball guns, it’s important that air doesn’t escape from the various gun components or it will malfunction. O-rings are replaced frequently in these units because they are such a vital part of the larger application.

So, as you can see, there is no denying the versatility and importance of these seemingly simple rubber rings. For more information on the various types of O-rings and which one is suitable for your specific application, don’t hesitate to get in touch with our knowledgeable team at Bearing Centre.

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