Duo Cone Seals

Duo cone seals or face seals are specifically engineered for rotating applications in extremely harsh environments where they withstand severe wear and prevent entry of harsh and abrasive external media. It is also known as Heavy Duty Seal, Face Seal, Metal Seal,Floating oil seal,Seal group and etc.

There are mainly 3 different types of Mechanical Face Seals

DO Type

DO type is the most common form that uses an O-Ring as a secondary sealing element

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DF type has an elastomer with a diamond-shaped cross section as a secondary sealing element instead of the O-Ring

XY Type is a variety of DO type, which is mostly used for high load and high speed rotation machinery.

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All these 3 types consist of a pair of metal seal rings mounted in two separate housings face-to-face on a lapped seal face. The metal rings are centered within their housings by an elastomer element. As the shaft is set in motion, one half of the Mechanical Face Seal remains static in the housing, while the other half rotates with its counter face.

   Chamical Analysis (%)   
CSiMnPSCrMoNi
1.1~603.2~3.60.5~1.0<0.20<0.1014~162.0~4.01.0~2.0
        

Metal Ring Material

The primary metal material of duo cone seal is high chromium molybdenum alloy FC15Cr3Mo. Adding chromium, molybdenum, nickel and other elements can effectively improve the strength, wear resistance and corrosion resistance of the alloy. The most appropriate material should be selected based on the temperature, rotational speed, corrosive environment, and maintenance requirements of the specific equipment on-site.

FC15Cr3Mo Composition

The primary metal material of duo cone seal is high chromium molybdenum alloy FC15Cr3Mo. Adding chromium, molybdenum, nickel and other elements can effectively improve the strength, wear resistance and corrosion resistance of the alloy. The most appropriate material should be selected based on the temperature, rotational speed, corrosive environment, and maintenance requirements of the specific equipment on-site.

Technical Standards
Roughness (Ra)Max Line VelocityHardness
0.073m/sHRC65~72
Operation Conditions
TemperatureInternal Operation PressureRecommend Velocity
-45~115℃240~345kpa1.8m/s

 

The roughness of sealing surface is also critical for wear resistance, the general requirement is ≤ Ra0.2μm. This can be achieved by flat or spherical grinding. Latest research indicated that under boundary lubrication conditions, the fine surface texture can provide storage space for lubricating oil, which is more conducive to the formation of oil film on the sealing surface and has an anti-wear effect. Therefore, the materials produced by casting and powder hot forging have a uniformly dispersed microporous structure, are suitable for high linear speeds, and have a long service life. Additionally, techniques like electrochemical corrosion passivation are employed to achieve these textures to prolong the ring’s durability.

Elastomer Material

Regarding  elastomer components of duo cone seals, they need to be selected according to the temperature, sealing medium, environmental corrosion and equipment operating conditions. Nitrile rubber can be used on most occasions, with its variants like low-temperature nitrile, fluorine rubber, hydrogenated nitrile rubber, and silicone rubber being alternatives based on specific requirements.

Material hardness influences properties such as elastic modulus, tensile strength, and elongation at break, with softer materials (ShoreA50~70) preferred for their ease of installation and enhanced floating performance.

  • The right rubber ring should be chosen to meet the specific application requirements.
  • The most commonly used rubber ring materials are NBR and silicone.

The table below gives a brief comparison between available rubber rings for reference.

FeatureNBRLTNBRHNBRSiliconeViton
Lowest Temperature-25°C-45°C-40°C-55°C-10°C
Hightest Temperature+110°C+115°C+135°C+165°C+180°C
Tensile StrengthGoodGoodGoodPoorGood
Abrasion ResistanceExcellentExcellentExcellentPoorGood
Oil ResistanceExcellentExcellentExcellentpoorExcellent
CostLowLowMediumMediumHigh

Application  mining，agriculture,infrastructure,construction

  • Tracked vehicles, Excavators and Bulldozers
  • Rotary tiller,Harvester
  • Dredger
  • Conveyor Systems
  • Coal Cutter,Forced Mixer
  • Continuous Miners
  • Shearer
  • Tunnel boring machine
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