DF-DGS6 Tandem seal
with intermediate labyrinth

1 Seal face
2 Seat
3 Thrust ring
4 Spring
5 Shaft sleeve
6 Intermediate sleeve
7 Housing
8 Clamping sleeve
9 Set screw
10 Adapter
11 Process side labyrinth
12 Internal labyrinth
F Flush - optional
CSV Containment seal vent
CSD Containment seal drain
GBI Gas buffer inlet



  • Dry gas seal for multiphase pump applications
  • DiamondFace sliding surface technology
  • Ideal for applications with Ethane, CO2, and similar media with low vapor margins
  • Shrouded rotating ring
  • Bi-directional
  • Ready-to-fit cartridge unit
  • Single, double, tandem, and tandem with intermediate labyrinth available


  • DiamondFace sliding surface technology for maximum operational performance under multiphase process conditions (liquid, vapor, supercritical)
  • Ideal upgrade solution for wet mechanical seals with dry running issues
  • Simple set-up: seal gas heating and nitrogen buffer are not required
  • Stiff sealing gap creates necessary heat and doesn´t require additional heating
  • Significantly lower leakage rate avoids icing problems with CO2 (Joule Thomson effect) and keeps emission rate low
  • High film stiffness in all operating modes
  • Proven reliable and economical solution
  • Adjustable to extreme narrow installation space - retrofits are easy to implement

Operating range

Shaft diameter:
D = 32 … 154 mm (1.26" … 6.06")

Pressure (static und dynamic):
DF-DGS6: p = 0 … 120 bar (1,450 PSI)
DF-PDGS6: p = 0 ... 250 bar (3,625 PSI)

DF-DGS6: t = -46 °C … +150 °C
(-51 °F … +302 °F)
DF-PDGS6: t = -100 °C ... +200 °C
(-148 °F ... +392 °F)

Sliding velocity:
vg = 0,6 … 140 m/s (2 … 459 ft/s)

For applications outside the standardized operating range mentioned, please contact us.


Primary seat and seal face: Silicon carbide with DiamondFace technology
Secondary seat and seal face: Silicon carbide with DLC coating (optional: DiamondFace technology)
Secondary seals: FKM, FFKM, PTFE (DF-PDGS6). Other elastomers available, depending on product gas composition
Metal parts: 1.4006 (410) and other stainless steels

Standards and approvals

  • NACE


Dimensions on request.

Sealing CO2 reliably with conventional mechanical seals is challenging due to the difficulty of maintaining the fluid in a phase appropriate for the seal type. With CO2, the phases range from liquid, supercritical to vapor, depending on the process parameters.

EagleBurgmann has performed extensive analysis, calculations, and testing, and developed with the DF-PDGS6 an effective and efficient sealing solution.

In our white paper "Advanced turbomachinery dry gas seal design solution for multiphase CO2 pump applications", we take a closer look at the special characteristics of CO2 and why they effect the safety and reliability of a seal. For more information, please feel free to contact us or download the whitepapger directly.

The DF-(P)DGS6 product brochure can be found in our Download Center.

Recommended piping plans

API Plan 76

API Plan 02
API Plan 12
API Plan 13
API Plan 32
API Plan 72
API Plan 75

Not recommended: Plan 11 and plans with cooler e.g. 21, 22, 23

Product variants



For multiphase pump applications (especially with CO2) with high pressure and both low and high temperature applications (see operating range). With U-cups and special dynamic sealing elements. Secondary seals made of PTFE.

Similar products

DF-SA DiamondFace

  • Cartridge design
  • Single seal
  • Balanced
  • Integrated pumping device
  • Stationary spring loaded unit
  • Inserted seal ring
  • Rotating mating ring
    (DiamondFace coated)


  • 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


  • Cartridge
  • Balanced
  • Independent of direction of rotation
  • Stationary multiple springs
  • Spring protection sleeve
  • Variant for operation with pressureless quench available (HRC2000N)
  • Dual seal with and without pumping screw (HRC3300NF, HRC3300N) available

Inquire about individual solutions

We develop and produce customer-specific special and individual solutions for every application.

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