DiamondFace-coated sliding faces in boiler feed pumps

DF-SAF(P)I seals as a solution against electrical corrosion


Boiler feed pump in a nuclear power station in southern Germany


Complicated repair jobs and expensive downtimes due to destructive electrical corrision


EagleBurgmann mechanical seals DF-SAF(P)I with DiamondFace

KKW Isar 1_K0525089.JPG

Ever since October 2010, the world‘s first mechanical seal with diamond-coated sliding faces has been operating in a boiler feed pump at a nuclear power station in southern Germany, to the complete satisfaction of the operator, E.ON. EagleBurgmann is the first and only company to offer this convincing technological solution which has currently been used in the SAF(P)I seal type.

PPT-040-2012_EON Isar.png

Illustr.: Boiler feed pump at the power station operator E.ON, equipped with EagleBurgmann DF-SAFI.

The outstanding advantage of the DF-SAF(P)I is that it puts an end to the electrical corrosion that has a destructive effect on the silicon carbide rings. Even without conditioning the feed water, e.g. by injecting ammonia, the seal with coated seal face and seat achieves a significantly longer service life. Complicated repair jobs and expensive downtimes are both minimized as a result.

Tested under scientific conditions, proven in practical applications

Before the DiamondFace coating was used, it was tested under scientific conditions and with the original fluid as part of a project undertaken jointly by EagleBurgmann and the Technical University of Graz in Austria. After more than 10,000 hours of continuous operation without any signs of electrical corrosion on seal face or seat, it was then possible to go on to successful practical application of the seal solution together with E.ON.

DF-SAF5_006b.tiff CaseStudy_Grafik_SAF_Germany.jpg

Illustr. 1: Mechanical seal type DF-SAF
Illustr. 2: Yellow parts = rotating, blue = stationary, gray = housing


  • Cartridge design
  • Single seal
  • Balanced
  • Independent of direction of rotation
  • Integrated pumping device
  • Double pressure balanced
  • Stationary springs
  • Seal face and seat with DiamondFace coating


  • Seal resistant to deformation, for very high sliding velocities and pressures
  • Specifically developed for use with water that has a high electrical conductivity in conjunction with high sliding velocities
  • Resistant to electrical corrosion
  • Economy due to standardized internal components
  • High flexibility due to adaptation of the connecting parts to the pump installation space
  • Optimum heat dissipation due to integrated pumping device
  • Lower power consumption than conventional seals
  • Non sensitive to shaft movements due to stationary design
  • Quick and easy installation because it is a preassembled unit
  • Only a few seal components

The operator‘s expectations were met in full, and as a result he ordered additional DiamondFace seals for re-equipping another pump. In the meantime, orders for power stations operated by other customers in the USA, South Korea and Switzerland had been placed and completed. Reports on the experience at EagleBurgmann's reference customer, E.ON, were one of the decisive factors leading to these decisions.

Reliable partnership

EagleBurgmann has been working successfully and in a spirit of partnership with E.ON for more than 20.years, to the mutual benefit of both partners. This confirms that EagleBurgmann's success is determined not only by innovative technology but also by the commitment and customer orientation displayed by its employees.

  • Shaft diameter: d1 = 120 ... 200 mm (4.72" ... 7.87")
  • Pressure: p1 = 70 bar (1,015 PSI)
  • Temperature: t = 300 °C (572 °F)
  • Sliding speed: vg = 70 m/s (230 ft/s)
  • Axial movement: +/- 3 mm
  • Seal face and seat: Silicon carbide with diamond coating (DiamondFace)
  • Secondary seals: EPDM (E), FFKM (K)
  • Springs: CrNiMo steel (G)
  • Metal parts: CrNiMo steel (G)


Contact us


for more information

Show locations

DiamondFace-coated sliding faces in boiler feed pumps

Download the solution flyer

PDF download - 467.2 KB

Mechanical seals DF-SA

Download the brochure

PDF download - 1.5 MB

More about the DF-SA

Learn more about our diamond-coated high-performance DF-SA seal

Further reference projects


Clean gas despite fluctuating operating conditions

Frequent starts and stops are a severe test for gas-lubricated compressor seals. Installed in an Argentinean combined cycle power plant is an EagleBurgmann supply system that provides a continuous gas flow rate for the seals and adapts it to changing conditions. Since then, the operational reliability of the compressors has increased significantly.

Read on for the entire case study

Clean sealing solution for demanding crystal production

Seals are a risk factor in the production of liquid crystals. If there is even the slightest contamination of the liquid crystals, this will later affect the image quality of the display. Read on to see which sealing solution Merck KGaA uses in paddle dryers for the production of liquid crystals.

Read on for the entire case study
United States

Convincing high pressure seals for pipeline pumps

Reduce maintenance costs for seal supply systems and extend MTBR intervals - EagleBurgmann's task was to significantly improve the availability of unmanned pump stations in a gas pipeline in Texas with single seals for multifluid pumps.

Read on for the entire case study

Cruise liners with DiamondFace-coated mechanical seals

Cruise liners have to reduce their sulfur emissions in Emission-Controlled Areas (ECAs). To accomplish this, light fuel oil is used in coastal regions - with significant consequences for the ship's fuel supply.

Read the complete case study

DF-M7N DiamondFace for tank drainage pumps

The chemical company Global Amines is one of the worldwide leading manufacturers of special chemicals. The "Southeast Bavarian Chemical Triangle", near Altötting, Germany is the location of the Gendorf plant. Global Amines produces preliminary, intermediate and finished chemical products here. EagleBurgmann successfully converted a chemical standard pump from a competitor's seal to an EagleBurgmann DF-M7N DiamondFace mechanical seal and achieved significantly increased pump and system availability.

Read the complete case study

DF-MFLWTI DiamondFace mechanical seal for refinery pumps

The TOTAL refinery at the Leuna chemicals site is one of the most state-of-the art facilities of its type in Europe. It processes around 30,000 tonnes of crude oil every day, most of which is pumped in from Russia.

Read the complete case study
Show all references

Excellence in Practice

With our free e-mail newsletter „Excellence in Practice“, you will receive first-hand information about current products, services, references and worthwhile industry insights.