According to the Oxford Dictionary, an o-ring is a round gasket that can contain a circular cross section which is often made of pliable material (rubber, plastic, etc.) that is used to create a tight seal in connections for pipes, valves, tubes, inlets, outlets, and much more. O-rings are one of the most common industry-used seals in machine design. This is because they are easy to make, cost effective, reliable, and are easy to install in many cases. O-rings can be designed and fabricated to operate in many conditions such as high or low temperature, under varying pressures, and for various media (the material flowing adjacent to the seal).
A Brief History of O-Rings
We have gone into the History of the Vulcanization of Rubber, without which o-rings would not be possible. O-rings were first patented in 1896 by J. O. Lundberg in Sweden. The patent for the o-ring in the United States would not come until 1937 when it was filed by a 72 year old Danish machinist, who also patented an air brake system for streetcars. During World War II, the U.S. government commandeered the patent and gave various factories the right to make it. The original patentee only received $75,000 for the patent in the 1950’s. According to the CPI Inflation Calculator, that is worth about $750,000 in today’s dollars for this billion dollar idea.
Like many components that are used in machinery, o-ring sizes come in both standard and metric. In the United States, we use an AS568 system and these rings are known as AS568 O-Rings. Metric o-rings are sized using millimeters.
Common Uses for O-Rings
If you have ever changed the oil on your car, you may notice a metal ring on the oil plug that is usually replaced when replacing the oil. This is an o-ring. O-rings are also used in various plumbing fixtures around your home that can be seen when disassembling a sink faucet, shower head, etc. In fact, if you were to take apart anything mechanical (even your wrist watch) you would find that it is laden with o-rings throughout.
When O-Rings Go Wrong
When an o-ring is incorrectly chosen, it can lead to premature seal failure, loss of media, and even damage to the equipment. The results can range from an inconvenience to something horrific. One of the most extreme examples of improper o-ring selection was a national disaster most Americans over a certain age vividly remember.
In January 1986, the Challenger space shuttle crashed due to an incorrectly chosen o-ring. The o-ring itself did not fail, but instead it was not designed to withstand the cold temperatures it would encounter on this particular launch. After the incident, Caltech professor Richard Feynman demonstrated how the o-ring used in the Challenger failed after subjecting it to cold temperatures and simple pressure.
See the video here:
An o-ring is one of the most common components that make things work in our industrialized world. Select the correct one and you have equipment that performs as it should and peace of mind. Select the wrong one and, as in the story of the Challenger crash, results can be catastrophic. We at Global O-Ring and Seal are dedicated to helping each and every customer select the optimum o-ring for every application. If you would like to learn more about o-rings or how Global O-Ring and Seal can help you, contact us – we’re here to help.