O-Rings are solid-rubber, doughnut-shaped seals used to block the passage of a gas or liquid when pressed between two mating surfaces.
They are amongst the most widely utilized seal designs in the world. Due to the number of ways they can be utilized, there are essentially an endless number of O-Ring sizes.
But despite the wide range of O-Ring sizes, every O-Ring has the same two dimensions: the inner diameter (ID), and the cross-section (CS). To attain an adequate seal, it must achieve proper compression, approximately 18-20% in the cross sectional characteristic. This creates a boundary to keep fluids in and contaminants out.
Article re-posted with permission from Parker Hannifin Sealing & Shielding Team.
Original content can be found on Parker’s Blog.
Sealing decisions are often left until the end of product development. By the time an email is sent to Gallagher Fluid Seals, the gland may already be fixed. This may not pose a problem in many applications, but it can often leave the seal engineer with few options. Having input from the seal expert in the early stages will allow for greater flexibility in choosing a seal and better chances at optimal sealing.