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API Standard 682 seal

Mechanical seals for pumps
Metal bellows seals
  • Compact design
  • Longer seal life
  • Suited for applications with extreme high andlow temperatures
  • Absence of dynamic O-Ring eleminates/reduces seal face hang-up
  • Bellows design minimizes variation in faceload due to shaft expansion or face wear
  • Resistant to abrasive particles in the medium, no shaft or sleeve fretting
  • Also available in double ply design


  • API 682 Category 2&3, Type C, Arrangement 1/2/3 seal
  • Balanced
  • Cartridge unit
  • Rotating metal bellows single/tandem seal
  • Shrink fitted seal ring and solid mating ring

Product specification example

Standards and approvals

API 682 / ISO 21049


Seal ring: Blister resistant carbon,
Silicon carbide SSiC (Q1), RBSiC (Q2)
Mating ring:
Silicon carbide SSiC (Q1), RBSiC (Q2)
Bellows: Inconel® 718 (M6)
Secondary seals: Graphite (G)
Metal parts: CrNiMo steel 316 (G), Carpenter® 42 (T4)

Operating range

Pressure single ply bellows: p = vacuum … 25 bar (… 363 PSI)*
Pressure double ply bellows: p = vacuum … 35 bar (… 508 PSI)
Temperature: t = -75 ºC … +400 ºC
(-103 ºF … +752 ºF)
Sliding velocity: vg … 23 m/s (… 75 ft/s)
Viscosity: … 1,000 mPas
Solids content: … 0.5 wt.%
* p >20 bar (290 PSI) on request.

Recommended applications

Refining technology
Oil and gas industry
Petrochemical industry
Chemical industry
Power plant technology
LPG plants
API 610 / ISO 13709 pumps
Process pumps

Recommended piping plans

Process side:
01, 02, 03, 11, 12, 13, 14, 21, 22, 23, 31, 32, 41
Between seals:
52, 53A, 53B, 53C, 54, 55
Atmospheric side*:
51, 61, 62, 65A, 65B, 66A, 66B
* Throttle bushing for tandem seal on request

Applicable ranges shown in the product introduction are limit values for each standard material.
Applicable ranges, performance data and figures can serve only as a guide for selection and therefore in actual use there will be some cases where general specifications cannot be applied due to unknown factors or constraints.
Please check the applicability before use.
The contents are subject to change without notice for improvement.


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