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Basics of an O-ring

One of the most common (and simplest) types of seal is an O-Ring. Used for numerous applications, the O-Ring is a critical part of many machines as it seals two or more parts together. They have a simplistic donut-shaped ring with a circular cross-section. That is typically molded from an elastomer.

O-Ring Characteristics

O-Rings help seal parts together and can prevent liquids and/or gases from going in or out of a specific area. These seals can prevent leaks in various objects, from pumps to valves, to cylinders and much more. The O-Rings are installed in a groove which is molded into the surface that needs sealing. These seals can be made leak-proof in cases where the static pistons and cylinders have fluid pressure that goes up to 5000 psi. What makes an O-Ring an excellent seal is its ability to return to its original shape after use.


Although O-Rings are the optimal solutions for sealing, there are a few limitations that come with them. For O-Rings, a few exceptions include rotary speeds that exceed 1,500 feet per minute, an incompatible environment for any elastomeric material, insufficient structure. And incompatible temperature, pressure or fluid chemical compatibility.

Advantages of O-Rings

O-Rings come with many advantages, here are just a few of them:

  • Cost efficient
  • Will seal over broad ranges of temperature, pressure, and tolerances
  • Long lifespan and failure is usually gradual and can easily be identified
  • O-Rings are lightweight and can typically be reused
  • Won’t cause structural damage

Common O-Ring Terms

  • Extrusion: The flowing of the seal’s body into a clearance gap under pressure.
  • Conformability: The seal compound’s ability to fill the minute irregularities
  • Sealabiltiy: The ability a material has to conform to a specific surface to block the flow of liquids.
  • Stability: The seal’s ability to resist rolling, twisting or shifting.
  • Wear: When the O-Ring diminishes gradually by friction.

O-Rings are a great way to seal if you want to prevent fluid or gases escaping from valves, connectors and more. They can handle static and dynamic operation in pneumatic and hydraulic uses. For more information on O-Ring use and application, contact the knowledgeable team at Automated Gasket Corporation today!