elastomers

The static seals used in large energy and industrial facilities can be challenging to install and difficult to replace. They must, therefore, function flawlessly for periods longer than 20 years. Up until now, the existing tools used to calculate the long-term performance of sealing materials for these kinds of applications have often led to the components being larger than actually necessary.

Freudenberg Sealing Technologies has now developed a method that takes into account the material changes at the molecular level when predicting the long-term durability of seals. The new methodology is more reliable than previous models and ensure fewer materials to be used.

The seals used in plant engineering must have a very long service life. Once they are installed – to protect offshore wind turbine towers from salt corrosion, for example – customers typically require that they perfectly fit for more than 20 years. The service life of a seal is limited based on two things: First, by setting or stretching (physical relaxation). And second, chemical changes cause the material loses its elasticity over time.

Under the influence of atmospheric oxygen or ozone, two basic effects that influence the aging of seals can be observed: First, the polymer chains and networks can fracture under mechanical stress, and second, additional oxygen bridges can develop in the network as a result of oxidation processes. Both effects influence important properties of relevance for seals such as stiffness, contact pressures or the ability to regain their original shape after deformation, also referred to as resistance to deformation.

Extrapolation with the Arrhenius Equation

To determine whether a material actually meets the requirements for a specific application, engineers usually conduct so-called “storage tests” in which the test specimen is exposed to temperatures well over 100° C for a longer period of time – usually 1,000 hours – to predict temperature-dependent aging. Engineers typically extrapolate the measured values using the Arrhenius Equation, a method named after the Swedish chemist and Nobel Prize winner Svante August Arrhenius.

Article re-posted with permission from Parker Hannifin Sealing & Shielding Team.

Original content can be found on Parker’s Website and was written by Fred Fisher, Technical Sales Manager for Parker O-Ring & Engineered Seals Division.

ASTM Elastomer Compounds

When looking at drawings to define a specific application or elastomer requirement: Is there value in using an ASTM elastomer compound

The popularity of multi-flavor drink dispensers, those touch screen wonders that offer dozens of beverage and flavor options to consumers, has grown during the past decade. Manufacturers are installing these complex machines in venues and locations throughout the world.

Elastomers and flavor transfer

But what’s great for an individual customer – a cherry-ginger-lime cream soda, for example – can play havoc with the elastomer seals inside the machine. Add in hygienic cleaning requirements and proper food contact certifications and equipment manufacturers can find themselves spending months chasing challenges like flavor transfer, leaks and material compliance approvals.

Freudenberg-NOK Sealing Technologies, a leading specialist in advanced sealing applications, has a portfolio of solutions to resolve these issues. The company, which runs the business operations for Freudenberg

Gallagher recently released our High Performance Elastomer Seals for the Instrumentation Industry White Paper.  This was written by Russ Schnell, an Elastomer Consultant contracted by Gallagher Fluid Seals, and a former Senior Application Engineer with the Kalrez® perfluoroelastomer parts business at DuPont.  This white paper is now available for download on our Resources page.

Below is the third and final section of the white paper, which will discuss the importance of proper seal and groove design.

Proper Seal & Groove Design

Proper seal design is a necessity for elastomer seals to perform reliably over the long term. Many of the instrument applications mentioned above use o-ring seals. The suggested compression for an elastomer o-ring seal to perform properly is typically a minimum of 16%, and a maximum of 30%. However, this range must also take into account the thermal expansion of an elastomer at elevated temperatures as well as any swell due to chemical exposure. Many of the elastomer seals used in instruments are small o-rings, which can create design issues. This is especially true for perfluoroelastomer parts which have a relatively high coefficient of thermal expansion (CTE). Fluoroelastomers have a lower CTE, making seal design easier at elevated temperatures.

Gallagher Fluid Seals recently posted our new Fluoroelastomer Basics webinar on gallagherseals.com.  This is the third and final section of our webinar, focusing on Considerations When Choosing a Fluoroelastomer. The full video is now available on our Resources page.

This video discusses considerations when choosing a fluoroelastomer, including temperature performance range, performance in harsh chemical exposure, and the need to take caution when using fluoroelastomer blends.

[embed]https://youtu.be/ETuFwz88SB0[/embed]

Gallagher Fluid Seals recently posted our new Fluoroelastomer Basics webinar on gallagherseals.com.  This is the second section of our webinar, focusing on Fluoroelastomer Materials. The full video is now available on our Resources page.

This section of the video discusses different fluoroelastomer materials, along with their mechanical and physical properties, and in which applications they're normally found.

[embed]https://youtu.be/pukqRYUXtbw[/embed]

Gallagher Fluid Seals recently posted our new Fluoroelastomer Basics webinar on gallagherseals.com.  This is the first section of our webinar, focusing on the Basic Understanding of Fluoroelastomers. The full video is now available on our Resources page.

In this snippet, learn the differences between elastomers and fluoroelastomers, and how the amount of fluorine in an elastomer affects it's chemical resistance and properties.

[embed]https://youtu.be/vb-HIQfrJM8[/embed]

Gallagher recently published its Failure Modes of Elastomers in the Semiconductor Industry White Paper, now available for download on our site.  This white paper discusses common issues that occur with elastomer seals in the semiconductor industry. The excerpt below is the fourth and final section of our new white paper, discussing Volatiles (offgassing) and Particle Generation.  To download the white paper in its entirety, visit our Resources Page, or click on the image to the right.

Failure Modes of Elastomers in the Semiconductor Industry

High performance elastomers are found in many applications in the semiconductor industry (see paper titled Perfluoroelastomers in the Semiconductor Industry). Though perfluoroelastomer (FFKM) seals are formulated to meet the highest performance requirements of integrated circuit (chip) manufacturers, even these elastomers can’t solve every sealing application nor will they last forever in service. Additionally, end users need to understand subtle performance differences between perfluoroelastomers in the same product line. For example, one product may be better at minimizing particle generation while another may be better for high temperature services.

Gallagher recently published its Failure Modes of Elastomers in the Semiconductor Industry White Paper, now available for download on our site.  This white paper discusses common issues that occur with elastomer seals in the semiconductor industry. The excerpt below is the third section of our new white paper, discussing O-Ring Stretch, Chemical Attack, Plasma Cracking, and Permeation.  To download the entire white paper, visit our Resources Page, or click on the image to the right.

Failure Modes of Elastomers in the Semiconductor Industry

High performance elastomers are found in many applications in the semiconductor industry (see paper titled Perfluoroelastomers in the Semiconductor Industry). Though perfluoroelastomer (FFKM) seals are formulated to meet the highest performance requirements of integrated circuit (chip) manufacturers, even these elastomers can’t solve every sealing application nor will they last forever in service. Additionally, end users need to understand subtle performance differences between perfluoroelastomers in the same product line. For example, one product may be better at minimizing particle generation while another may be better for high temperature services.

Gallagher recently published its Failure Modes of Elastomers in the Semiconductor Industry White Paper, now available for download on our site.  This white paper discusses common issues that occur with elastomer seals in the semiconductor industry. The excerpt below is the first section of our new white paper, discussing groove design and seal leakage.  To download the entire white paper, visit our Resources Page, or click on the image to the right.

Failure Modes for Elastomers in the Semiconductor Industry

High performance elastomers are found in many applications in the semiconductor industry (see paper titled Perfluoroelastomers in the Semiconductor Industry). Though perfluoroelastomer (FFKM) seals are formulated to meet the highest performance requirements of integrated circuit (chip) manufacturers, even these elastomers can’t solve every sealing application nor will they last forever in service. Additionally, end users need to understand subtle performance differences between perfluoroelastomers in the same product line. For example, one product may be better at minimizing particle generation while another may be better for high temperature services.