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Threaded Flange

Threaded flanges are probably the most recognisable of all flanges due to their screw thread design that is used to connect it to the pipe. Threaded flanges, also known as screwed flanges (for obvious reasons), require a male and female thread to create a connection...

Slip On Flange

A slip-on flange can also be known as a hubbed flange, which, as the name suggests, has a hub with a very low profile. Why is this important? Because this type of ring type joint gasket has an internal diameter larger than the connecting pipe, allowing you to slide it...

Weld Neck Flange

Also known as tapered hub flanges or high hub flanges, weld neck flanges are a specific type of gasket with a protruding ridge and long neck used to connect pipework and provide you with a high-quality seal. Weld neck flanges, in particular, are a popular choice when...

Nitrile vs Viton® – What is the Difference?

As you start to make a decision about what type of O-rings to purchase for your business, you might wonder what material is the most suitable for your unique needs. Every business operation has different requirements for their O-rings, such as the temperature,...

Aflas vs Viton

When it comes to choosing O ring suppliers in the UK, you’ll find that there are a wide range of materials on offer for you to choose from. Many people find that the options can seem quite overwhelming, with some materials having similar properties but offering...

EPDM Gasket

Both the automotive and construction industries have started to use EPDM gaskets more frequently in recent times. This rubber material is UV light resistant and has many fantastic properties that make this part highly effective for a wide range of processes. Keep...

Metal Gaskets

When comparing gaskets for use within your business processes, you’ll find that these can be made from a variety of materials. Metal gaskets are a very popular option, offering many advantages over other materials. When looking at sealing product options, make sure...

AFLAS o ring

O rings come in many different dimensions, thicknesses, and materials. And it is the various different materials that o rings can be manufactured from that make each o ring unique and suitable for specific applications. In fact, there are hundreds of different types...

O Ring Vulcanization Process

With years of o ring knowledge and experience in o ring vulcanization, we're one of the leading experts in providing the right sealing solution for you. To view our full range, visit our O-ring product page, with a wide selection and something to match every...

What is a Window Seal?

A window seal is something that nearly all of us will have seen in our homes or workplaces and is designed to help make your building more comfortable. Within our range of Sealing Specialist Products, we offer a selection of window seals designed for various...

See our latest catalogue for all the services we offer.

GRAPHITE MOULDED DIE
FORMED RINGS

Flexible graphite die-formed rings are valve stem packing rings manufactured from high purity flexible graphite foil with a corrosion inhibitor but without any binders, elastomers or fillersGraphite Moulded Sealing Rings are produced using a pre-determined length of flexible graphite tape which is then, using a mould, compressed to form a solid ring of precise density and size. For ease of installation, when the valve bonnet cannot be removed, split rings should be used. 

We have four model numbers of graphite moulded rings, Style 1, 3, 4 and 5 

Model 1, 3 and 4 are manufactured in exactly the same way and have the same main characteristics, only the purity of the graphite used changes.  

Model 1 – 98% is commercial grade and makes up the vast majority of usage for industrial applications. 

Model 3 – 99% conforms to Shell material specification MESC SPE 85/203 

Model 4 – 99.85% is exclusively specified by the Nuclear power industry 

 

  Model 1  Model 3  Model 4 
Graphite Purity – %  98  99  99.85 
Ash Content – %  2  1  0.15 
Density Range – g/cm³  1.4-1.8  1.4-1.8  1.4-1.8 
Sulphur Content – ppm  ≤300  ≤300  ≤300 
Chloride Content – ppm  ≤25  ≤10  ≤10 
Fluoride Content – ppm  ≤25  ≤10  ≤10 
Halogen Content – ppm  ≤100  ≤50  ≤50 
Oxidation rate in air at 670⁰C – %/hour  <5  <4  <4 
Passive corrosion inhibitor  Yes  Yes  Yes 

Valve Stem Duties 

  • Maximum Operating Temperature 
  • Steam : +650⁰C    Oxidising : +500⁰C    Non-Oxidising : +1000⁰C 
  • Minimum Operating Temperature -200⁰C 
  • Maximum system Pressure : 250 bar 

Typical Applications 

  • Valves and rotary equipment handling virtually any media 
  • High temperature steam 
  • Heat transfer media 
  • Petroleum products  
  • Demineralised water 
  • Inorganic and organic acids and alkalis, hot waxes and oils 

Material Properties 

  • Compatible with media in the range pH 0-14 
  • No loss of volatiles at high temperature 
  • Lower limiting temperatures apply when used with oxidising agents 
  • Thermal conductivity, ring of density 1.4g/cm³ : Axial 400W/mK : Radial 6W/mK 
  • Coefficient of friction to steel : 0.05 

Main features 

  • Outstanding sealing performance over long adjustment-free periods 
  • Excellent chemical resistance 
  • Very wide temperature range   

Model 5 

These rings use the 98% graphite purity of Model 1 but with the addition of a special low friction coating which has been sinter bonded to the graphite before the moulding process which helps ensure maximum service life.

  Model 5 
Graphite Purity – %  98 
Ash Content – %  2 
Density Range – g/cm³  1.4-1.8 
Sulphur Content – ppm  ≤300 
Chloride Content – ppm  ≤25 
Fluoride Content – ppm  ≤25 
Halogen Content – ppm  ≤100 
Oxidation rate in air at 670⁰C – %/hour  <5 
Passive corrosion inhibitor  Yes 

Valve Stem Duties 

  • Maximum Operating Temperature +350⁰C 
  • Minimum Operating Temperature -200⁰C 
  • Maximum system Pressure : 250 bar 

Typical Applications 

  • Valves that handle dry gases and other fluids where friction on standard graphite seals is unacceptably high. 
  • Valves that suffer judder, hesitation or erratic action due to carbon pick-up or high-spot friction on the spindle 

Material Properties 

  • Compatible with media in the range pH 0-14 
  • No loss of volatiles at high temperature 
  • Lower limiting temperatures apply when used with oxidising agents 
  • In comparative tests Model 5 displayed exactly half the friction coefficient of standard graphite and provided a continued low friction performance over more than 300 cycles 

Main features 

  • Greatly reduces the torque needed for efficient valve action 
  • Saves on power consumption and enables smaller actuators to be used 
  • Lowers the break out friction for smoother valve operation 
  • Retains exceptionally low friction characteristics  for up to 20,000 valve cycles 
  • Subsequent manual adjustment extends performance to 60,000 cycles 
  • Fire-safe capability enables rings to be used in plant subjected to fire rating tests 
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