How important are o-rings? Like the atom, the tiny o-ring has a significance many times its size. In fact, nuclear plants depend on elastomer o-ring seals to maintain the integrity of pumps and seals crucial for the safe operation of plant cooling systems, says Power Engineering International. Case in point: the Indian Point nuclear power plant in Buchanan, New York, recently had to shut down in order to repair an o-ring used to connect the lid of the reactor to the body of the reactor vessel used for nuclear fission, Lohud reports.
As this illustrates, o-rings usually only get attention when something goes wrong. But most of the time, they’re quietly working behind the scenes making sure everything works correctly, the unsung heroes of technology. Here’s a look at four ways the humble o-ring has revolutionized the history of technology and changed the world.
Bringing Water to Homes
Before o-rings were called “o-rings,” their prototypes were already helping bring water to homes. As the Industrial Revolution advanced, indoor plumbing began to be added to wealthy homes in the 19th century. In order to seal piping counter-bores effectively, plumbers began using gaskets constructed from large cross-section rings made of india rubber, which had recently come into widespread use.
Since then, o-rings have come to play a prominent role in plumbing. For example, kitchen faucets use o-rings to keep water from leaking near their base. Wax o-rings also seal the toilet flange that connects your toilet to the drainpipe in the floor of your bathroom to prevent leaking.
Lighting Up the World
Shortly, after india rubber rings were introduced into piping, the prolific inventor Thomas Edison began finding other uses for them. In 1882, Edison included rubber rings in two of his invention patents. One was for a gas sealing ring in a water faucet. This was evidently inspired by the current use of india rubber rings in water pipes.
Edison’s other use of rubber rings was far more innovative. In another 1882 patent, Edison used a round rubber ring at the neck of a glass light bulb to seal the mercury in and keep the air out. This was necessary because oxygen caused the carbon filament in the bulb to burn up. By using a rubber ring to seal the bulb from air, Edison was able to develop a longer-lasting, more practical light bulb, which eventually brought indoor lighting to the world.
Empowering Air Travel
While Edison’s rubber rings served a function similar to o-rings, they were not very efficient compared to later o-rings. The first recognized o-ring patent was filed in 1896 by Swedish inventor J.O. Lundberg. However, today’s o-rings descend from a design created in the 1930s by Danish-American inventor Niels Christensen, reports ThomasNet.com.
Christensen had previously designed an airbrake system for use in electric streetcars. While on airbrake ideas, Christensen discovered that he could seal a piston cylinder by inserting a rubber ring into a groove a little larger than the ring’s minor radius. Christensen applied for a patent for his idea in 1937. He intended to license it to United Aircraft for use in hydraulic cylinders in planes, but after Pearl Harbor, the U.S. government seized his patent, deeming it essential for the war effort. Christensen received $75,000, later supplemented by another $100,000 to his heirs, and his design passed from proprietary use into general application. Today, o-rings are an essential part of aircraft and spacecraft design, supporting hydraulic systems for brakes, landing gear and wing flaps.
Supporting Medical Devices
Today, one of the most important applications of o-rings is used in medical seals. Medical devices such as syringes, insulin pumps, and surgical tools frequently require liquids and gases to be pumped, drained, contained or handled in other ways. Leaking can introduce contamination, potentially damaging both devices and patients. O-rings protect medical devices from contamination.
To serve this function, o-rings must be made to very precise specifications. Manufacturers who make medical seals offer over 7,000 o-ring sizes to fit the wide range needed for medical devices. Medical o-rings are also made out of special materials such as medical grade elastomers, designed to be resistant to heat, chemical change, and gas permeation, so that they are less susceptible to alteration and damage that can allow contamination. Thanks to medical o-ring providers, devices such as syringes are safe to use, saving countless lives.