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Everything you need to know about Manway Gaskets

When it comes to manway gaskets, we want to keep things simple, introducing them as the small sealing ring found in hatches/openings that are constructed for large tanks. Openings which give people access to the inside of the aforementioned tanks and vessels. The...

How Do You Recognise a Quality Gasket?

A gasket is a very simple item that is reasonably inexpensive. Considering how gaskets work, you may be facing a costly bill should a gasket fail. Choosing a quality gasket from Specialist Sealing Products helps to create a seal that will last until well after the...

5 Common Gasket Failures

Common Failure Causes  A blown head gasket in a vehicle is something that needs to be fixed promptly. If left untouched, you run the risk of seriously damaging your engine. Knowing what causes gasket failure or gasket problems is the key to gasket failure prevention,...

O-ring Size Guidelines

The performance of an O-ring seal depends largely on two factors— the right material and the right size. However, determining the right size O-ring is usually the hardest part when it comes to choosing the right O-ring for an application.   Unfortunately, selecting...

Tips for Proper O-Ring Installation

  An O-ring is a crucial component of a fluid system, and how it is installed can make or break that system. To ensure the success of an application, O-ring requires not only careful material selection and design but also proper installation procedures. A small...

Why Colour Matters When Choosing Gaskets?

Gasket manufacturers have turned to colour coding gaskets to make the selection and categorisation of the product more accessible.   It is possible to identify the winding and filler materials that were used for fabrication by the colouring of the outer top side of...

Materials that can be Used in Producing Gaskets

Seals and gaskets are meticulously manufactured to be able to withstand the exacting conditions under which they function. Not only does a gasket seal two distinct parts and allow the containment of extreme temperature fluids, steams and gases, but it must meld the...

Choosing the Perfect Gasket for Your Needs

The perfect gasket choice and fit is an essential component of engines, appliances, and industrial machinery projects. They are a fundamental part when engineering anything from power tools to oil drills. A high-quality manufacturer of gaskets and seals will use only...

Manufacturing of High-Quality Gaskets

A large number of engineering and machinery applications use gaskets. This mechanical seal is employed whenever gaps between two or more surfaces are joined together. This process is also required to prevent leakage and withstand the extremes of compression when...

O Ring Materials Selection

This is a quick overview of the various O-Ring materials that are available for applications and found at select UK O-Ring suppliers. When it comes to Specialist Sealing Products, it is a good idea to be clued into every option that is on the market. The materials can...

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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