Item Part no.
DIN 24250
1.1 472 Seal face
1.2 520 Sleeve
2 412.1 O-Ring
3 474 Thrust ring
4 477 Spring
5 475 Seat (G11)
6 412.2 O-Ring
7 412.3 O-Ring
8 441 Housing

Direction of installation: - from the impeller side HR10 - from the bearing side HR11



  • Single seal
  • Balanced
  • Independent of direction of rotation
  • Multiple springs stationary
  • Seat rotating
  • Seat arranged directly behind the impeller
  • Spring protection sleeve
  • Variant with cylindrical spring and acc. EN 12756 (HRZ1) available
  • Variant as cartridge with/without guide sleeve for application with/without quench (HR2, HR3)
  • Dual seal as cartridge unit (HRKS-D) available


  • Especially for application in solids containing media without external flush or internal product circulation. Solids content 40 % (single seal) and 60 % (double seal)
  • Operation under vacuum without seat locking possible
  • Pumping screw for increased circulation available
  • Springs are protected from product and leakage

Operating range

Shaft diameter:
dN = 36 ... 270 mm (1.4" ... 10.63")
Pressure: p1* = 16 bar (230 PSI)
t = -20 °C ... +160 °C (-4 °F ... +320 °F)
Sliding velocity: vg = 10 m/s (33 ft/s)

* For operation under vacuum it is necessary to arrange for quenching on the atmosphere side.


Seal face: Silicon carbide (Q1, Q2)
Seat: Silicon carbide (Q1, Q2)

Standards and approvals

  • EN 12756


Direction of installation:
  • From the impeller side: HR10
  • From the bearing side: HR11

Product variants

Cartridge-type single seal with guide sleeve (Item no. 2) for use with quench. Insert (Item no. 1) either metal or silicon carbide.
Cartridge-type single seal. Insert (Item no. 1) either metal or silicon carbide. Optional without maintenance rinsing.
Double seal in cartridge design for operation in barrier or buffer pressure (does not open if barrier pressure fails), available alternatively with a pumping screw for a higher rate of circulation. Torque transmission e.g. by shrink disk.
Single seal with cylindrical spring and type G76 seat. For installation in covers with installation dimensions according to EN 12756 B or U. Installation length l11 corresponds to max. l1k. Intermediate sizes on request.