Large O-rings are the most massive sized O-rings available for sale.
Some are offered through sizing charts and mass produced, while others
must be custom made to fit certain dimensions. They are made out of
elastomeric rubber or thermoplastic materials like silicone, Teflon or
Viton, and exhibit the same properties.
Large O-rings are used in most process industries, specifically within the chemical, hydrocarbon, pharmaceutical, food processing, beverage and electronics industries. The multitude of applications for large o-rings includes thread tube fitting, which involves a third piece between two tubes that connects them, known as a union piece. This piece allows access for system check-ups and management of leaks and such. Fitting military gland designs, which are larger than most O-ring grooves, is also one example of how large o-rings are utilized. There is also the production of flat panel displays, which are built to support the weight of an object perpendicular to a wall. Such a display cannot shake or move and therefore requires the soft buffer of an o-ring between the wall and the mount part screwed into it. All of these applications require the use of a basic o-ring, except with a larger width, outside diameter and inside diameter, to support the proper magnitude of the product it is part of supporting. Large o-rings are usually rubber rather than metal, particularly in reference to the three applications just discussed.
There are several different methods to determine the size of an O-ring or the desired size for a specific application. O-ring gauges are devices that measure the size of any O-ring by placing the O-ring being measured around two halves of spindles until it is a tight fit. The spindles expand until tight, and a size is sown in a digital window. Digital calipers perform a similar way, but measure the O-ring by a size chart. Shadow graphs match an O-ring with its correct standard sizing by providing life-size drawings of O-rings. All O-rings have standardized sizes among different countries, the most popular of which is the AS568 O-rings. Large o-rings are often sold as a part of an o-ring kit, with a variety of o-ring sizes packaged together by an o-ring manufacturer. For companies that have a multitude of products or systems requiring o-rings, a kit including all the sizes they need would be a smarter investment then buying each o-ring size individually.
Large O-Rings - Allied Metrics Seals & Fasteners, Inc.