Item Description
1 Seal face
2 Stationary seat
3, 3a O-Ring
4 Spring
5 Driver
5a Set screw



  • Single pusher-type seal
  • Unbalanced
  • Super-sinus spring
  • Independent of direction of rotation
  • Short length, according EN 12756 (L1KU).


The BT-C7 mechanical seal range has a robust design for universal application. The seal is bi-directional, unaffected by the direction of shaft rotation and is positively driven by set screws. With super-sinus spring.

Operating range

Shaft diameter:
d1 = 16 … 100 mm (0.79" … 3.94")
Pressure: p1* = 12 bar (16 bar) (174 PSI)
t* = -35 °C … +180 °C (-4 °F … +356 °F)
Sliding velocity: vg = 20 m/s (66 ft/s)

* Dependent on medium, size and material


Seal face: CrNiMo steel (G), Tungsten carbide (U)
Seat: Carbon graphite resin impregnated (B), Carbon graphite antimony impregnated (A), Tungsten carbide (U)
NBR (P), EPDM (E), FKM (V), FFKM (K)
Metal parts: CrNiMo steel 1.4401 (G)

Standards and approvals

  • KTW
  • W270
  • ACS
  • WRAS
  • NSF
  • FDA
  • DM 174/04


Seat ring of alternative seats can be supplied with short tail or with pin to block the seat and prevent seat rotation.

Product variants


Like the BT-C7, but seal face and seat made of brazed tungsten carbide (U). This version is suitable for media with abrasive characteristics.

Item Description
1 Seal face housing
1a Brazed seal face
2 Stationary seat housing
2a Brazed stationary seat
3, 3a O-Ring
4 Spring
5 Driver
5a Set screw