elastomeric seals

At Gallagher, we often receive unique requests for challenging projects, and customers who might be intimately familiar with elastomeric seals might have a better fit utilizing metal seals for their application. But, why might someone use a metal seal?

A metal seal is used when the application conditions are outside the specification limits of a polymer; extreme heat, extreme cold, extreme pressure, or a vacuum. With significant resilience coupled with the right material selection/coating for an application, a metal seal can be a very durable seal performing dependably year after year.

In order to understand metal seals a bit better, GFS thought it might be worthwhile to discuss metal seal terminology, and different profiles.

This is a short guide to reference common terms and profiles that may to new to end-users.

In this blog post, we will discuss the following:

• Common terms of metal seals
• Standard formed metal seals
  • O-rings
  • C-Rings
  • Spring energized C-Rings
  • U-Rings
  • E-Rings
  • Metal Wire Rings
  • Axial C-Seal
  • Boss Seal

But first, let's go over some common metal sealing terms.

The spectrum of elastomers range from very simple forms, like the natural rubber already in use in the 19th century, to modern, high performance elastomers from the second half of the 20th century.  They are continually being improved.

This blog article will be the first in a two-part series discussing the many different elastomer materials available today, as discussed in Freudenberg's The World of Freudenberg Sealing Technologies.

Natural Rubber (NR)
In its original form, latex is greasy and sticky. Natural rubber is an elastic polymer, built on isoprene as its monomer. To make it usable technically, the long polyisoprene chains of natural rubber are cross-linked with one another through vulcanization – which involves the addition of sulfur under pressure and heat.

In the process, sulfur atoms insert themselves between the double bonds of adjacent chain molecules – the majority of the double bonds are maintained. The result is a three-dimensional molecule network whose parts can only shift against one another within certain limits.

Gallagher Fluid Seals is a longtime partner of DuPont®’s, having specified thousands of DuPont perfluoroelastomer parts over the past few decades.

While elastomers were originally created as an alternative to natural rubber, they have expanded to include materials such as high-performance perfluoroelastomers for demanding applications.

These materials can also be used in place of plastics in most, if not all, applications. DuPont is at the forefront of perfluoroelastomer development, creating elastomers with properties that can help meet highly specific application requirements.

Read on to learn more from Dupont about the differences between elastomers and plastics, and how elastomeric seals perform compared to plastic seals.