What is the difference between O-ring and gasket?

O-rings and gaskets are often used to create a sealed mating surface between components. When multiple components are joined together, we can install an o-ring or gasket at the place where they meet, the individual components will seal the components so that they do not leak.

You can find o ring and gasket in everything from machines and motors to plumbing fixtures and gas pipelines. However, it is critical to know which one you should choose when replacing a seal.

As we have introduced what gasket it is in this article: What is a gasket and how to select it, so we don’t talk too much here.

1. What Is an O-Ring?

O-ring is also called packing joint or toric joint, it is a type of mechanical seal made of a circular-shaped elastomer material with a hollow center. All o-rings have the same shape and can be designed into multiple sizes. As they are cheap, easy to manufacture, reliable, and easy to install, o-rings have become one of the most common seals used in machine design.

O-rings are installed in the groove and compressed during the assembly process between two or more parts, creating a seal at the interface. Some O-rings can withstand pressures in excess of 5000 pounds per square inch (PSI). Even when exposed to severe pressure, the o-ring can maintain its integrity while preventing liquid, gas, or air from escaping using their respective components.

2. What is the difference between O-ring and gasket?

Both the gasket and the o-ring have the same basic function of preventing liquid or gas from entering or exiting. The o-ring is a simple circular gasket composed of elastomeric material, and the gasket is a flat seal composed of any material or shape.

When deciding if an O ring or a gasket is better for your equipment designing, the shape of the seal is a critical factor for your choice. In some cases, only gaskets can work well because O-rings must require a groove to sit in.

Another key factor is the working environment, including temperature and pressure. Both O-rings and gaskets can work in a wide temperature range, but the gasket is a better choice in extreme temperatures. At the same time, O-rings are an excellent choice in extreme pressure. To a certain extent, O-rings perform better with increasing pressure, while the effectiveness of the gasket will decrease.