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How choosing the correct gasket reduces risks

Health and Safety across any industry are vital, especially so in industrial facilities and settings.  Why?  Because harmful leaks and emissions must be avoided at all costs to avoid serious accidents or injury to your teams and property.  That’s why having the right...

How to tighten your bolts perfectly

How to tighten your bolts and which tools you should use to achieve the perfect seal is not as seamless and straightforward as we would like. Various factors come into play in these situations, such as bolt grade, size, and even application type.  Tightening torques...

Static and Dynamic o rings

A range of factors and application dynamics come into play when choosing a particular type of o ring.  You need to understand the type of seal exert you require, the dimensions, and even compounds.  Due to the nature of an o ring and its overall design, o rings use...

Gasket Sealants

Fortunately, no one gasket suits a range of applications, but rather we have a multitude of gasket sealants available to meet various specifications and requirements.  Ultimately, sealants are used to effectively ensure gasket seals.  Helping to extend a gasket's life...

Types of industrial gasket material

Different industry sectors will use different types of gaskets and different types of gasket materials.   And of course!  Different industrial gasket materials will be much better suited to some industrial processes and applications compared to others.  As different...

Keeping a close eye on the gaskets your applications use

Gaskets are vital elements to any piping system and application that requires creating the perfect seal in order to prevent leaks.  This is the main role of a gasket, to provide a good seal, with some gasket materials sealing better than others in certain...

O Ring Colour Identification

O rings come in various colours, and it's important to understand what these colours indicate as the o rings you choose will affect your overall process application.  Ultimately, different o ring colours are used to help differentiate between different materials. ...

Spiral Wound Gasket Compressibility and Pressure Ratings

In order to form a reliable seal, spiral wound gaskets do require a certain degree of pressure.   The applied pressure allows the gasket to be compressed tightly between the mating surfaces preventing any leaks from occurring.  Factors such as operating temperature...

Elastomeric Compounds

What is elastomer?  Elastomeric compounds are rubber seals produced using natural rubbers or manufactured by the chemicals industry.  Elastomeric sealing compounds consist of between 50-60% rubber; the remainder of the compound consists of fillers,...

Is there such a thing as the right flange gasket?

We cannot stress enough how important gaskets and seals can be. Gaskets are vital for an application's reliability and integrity, and trust us when we say, choosing the right gasket now can help you avoid costly issues in the future.  Taking a closer look at pipe...

BACK-UP RINGS

Also referred to as anti-extrusion rings, these are not actual seals themselves but are used in conjunction with ‘O’ Rings and are installed to prevent the extrusion of an elastomeric ‘O’ Ring in its housing groove under certain operating conditions. They can be used in all applications but primarily are used when higher pressures or pressure spikes, higher temperatures and / or larger extrusion gaps form part of the operating conditions. 

They are normally recommended for applications where; 

  • Fluid media pressure exceeds 10 MPa 
  • ‘O’ Rings of low strength elastomers are used 
  • Adverse mechanical conditions prevail 

Back-up Rings

Materials available

  • Virgin PTFE 
  • Filled PTFE – Fillers are sometimes added to the Virgin PTFE to improve some of its basic properties and characteristics, such as, enhanced compressive strength and thermal conductivity, reduced thermal expansion and reduced wear 
  • PEEK™ (from Victrex plc) 

This range of materials, the chemical resistance of which is almost universal, with the exception of molten alkali metals, fluorine gas and elemental fluorine, making them the ideal material choice for ‘O’ Ring Back-Up Rings. 

There are three main manufactured styles of Back-Up Rings 

Spiral Wound – A spiral of two turns is the most commonly used type of construction. This method of production allows the back-up ring to be easily opened to enable easy installation over a shaft and it also ensures the ‘O’ Ring is supported around its entire diameter. 

Solid – Generally used on very small diameters but can be difficult to install 

Endless Split  Single turn can also be supplied as an endless configuration to ensure good support. These can also be scarf split if required although we do not generally recommend this as extrusion can occur at the split 

Alternative Material Options 

Nitrile or Viton Back-Up rings are also available and have the following characteristics 

  • Molded in one-piece contoured design which enables the ‘O’ Ring to keep its shape under high pressure 
  • Can be stretched easily into place 
  • Do not cause the localised wear on ‘O’ Rings  

 

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