Robust component in ensuring sterile vaccine production

HSMR double seal for foam breakers of a pharmaceutical company


Poor lubricating properties of the steam condensate lead to oxidation


Increase the service life of the seals, prevent contamination of the biocultures


Double seal HSMR with DiamondFace from EagleBurgmann


More than 100 agitators at the Belgian site of a multinational pharmaceutical company are equipped with mechanical seals from EagleBurgmann. The seals are installed in vessels with capacities of either 100 or 800 liters that the pharmaceutical company uses to produce biocultures for the production of vaccines.

The vessels are equipped with an agitator with bottom entry and a foam breaker with top entry. The foam breaker eliminates the foam that is generated by the bacteriological process on top of the liquid product in the vessel. Due to the increasingly stringent guidelines of the US Food and Drug Administration (FDA) for the production of vaccines, the pharmaceutical company decided to use the double seal HSMR from EagleBurgmann to seal the shafts of the foam breakers. At speeds of 1,500 revolutions per minute, these seals reliably prevent the product from entering the atmosphere via the shaft passage or outside microorganisms from entering the product. They are therefore an important component in ensuring sterile vaccine production.


Of great importance for biotechnical processes is the hygienic design of the seals. The HSMR double seals meet this high requirement with a smooth, dead space-free surface contour. In addition, the seals withstand temperatures of up to 121 °C (249.8 °F) during sterilization for periods of 20 to 60 minutes, since production is subject to the requirements of certified cleaning in place (CIP) and sterilization in place (SIP) processes.

SPU circulation pumps from EagleBurgmann supply buffer fluid to the mechanical seals. Only steam condensate, i.e. high-purity water, is permitted as a barrier medium for the production of the biocultures. Due to the low electrical conductivity, however, the steam condensate has poor lubricating properties. The sliding faces of the seal are therefore designed in hard/hard pairing and highly precise hydrodynamic grooves ensure better distribution of the steam condensate.

It was nevertheless unavoidable that the low electrical conductivity of the barrier fluid would lead to oxidation of the silicon carbide and thus to the destruction of the sliding faces. The challenge for EagleBurgmann now was to optimize the seal face and the seat made of the FDA-compliant material silicon carbide on the product side. A special silicon quality was found which prevents oxidation and silicon carbide particles from contaminating the biocultures. The materials for the O-rings and the seal were also optimized.


The result was not yet one hundred percent satisfactory. Therefore, the sealing specialist resorted to a technology that had been already developed in 2007 together with the Fraunhofer Institute for Coating and Surface Technology: Each seal face and seat was replaced by a version with a DiamondFace coating that protects against wear caused by dispersed solids in the product and partial dry running of the seal. This technology involves applying a microcrystalline diamond layer of up to 15 μm to the seal faces under vacuum and at temperatures of 2,000 °C (3,632 °F) by chemical vapor deposition (CVD). This extremely hard, thermally conductive and chemically robust coating gave EagleBurgmann control over the consequences of the low electrical conductivity of the steam condensate.

After all of these improvements, the service life of the mechanical seals at the foam breakers increased significantly.

At the Belgian site, the pharmaceutical company benefits above all from the technical support and documentation diligence of EagleBurgmann. This includes the analysis of system failures, repairs and the replacement of seals. EagleBurgmann maintains a workshop in Belgium exclusively for customers in the pharmaceutical industry and was audited by the customer with the Belgian production site. In accordance with quality standards, all service and repair steps are reliably documented at a high level.

Interested in learning more about our wide range of products & services for the pharmaceutical industry? 

EagleBurgmann provides extensive support in the field of sealing technolgogy. Read more.

  • Vessels with top and bottom entry
  • Shaft diameter: d1 = 40 mm (1.57")
  • Tank pressure: p1 = Vacuum ... 1 bar
  • Temperature: t = 4 °C … 128 °C (39.2 °F … 271.4 °F)
  • Foam breaker speed: n = 1,500 min-1
  • Medium: Biological cell cultures

Solution: Robust component in ensuring sterile vaccine production

HSMR double seal for foam breakers of a pharmaceutical company

PDF download - 158.0 KB

HSMR34 / SeccoMixR Product Leaflet

Mechanical seals for agitators, mixers, dryers, kneaders and other special machines. The true all-rounders when it comes to aggressive, sticky or viscous media or when solids content is high.

PDF download - 2.2 MB

Further reference projects

China, Mainland

10 years ahead

Between June 2017 and March 2019 the Hengli Group constructed an integrated refining and chemical complex in the Chinese harbor town Dalian where 20 million tons of crude oil are processed every year. EagleBurgmann advised the company Hengli concerning the selection of mechanical seals and supply systems for the whole plant and supplied more than 95 % of the components in use. 

Read the complete case study
KeyVisual_CaseStudy_National Grid
United Kingdom

10 years of reliability: Protecting the heart of Great Britain’s natural gas infrastructure from failure

In Great Britain, a shortage in natural gas supply has severe consequences: Since the country switched from coal-fired to gas-fired power stations, a gas supply shortage makes households and industrial consumers not only vulnerable to failing heating and gas stoves, but also to power outages. Companies along the value and transportation chain of natural gas are therefore especially dependent on reliable equipment.

Read the complete case study
Feuer und Flamme_DRO_Head3

100 percent performance at 300 degrees

Things get hot in rotary kilns, very hot in fact. In the production of cement, for example, the thermometer measures more than 1,000 degrees Celsius. Sealing systems from EagleBurgmann, a company of the Freudenberg Group and EKK, make sustainable contributions to environmental protection, energy efficiency and process reliability under these "fiery" high-temperature conditions.

Read the complete case study

A Partnership to build on

Our modern civilization is quite literally built upon cement. Today, building materials made from cement are used in buildings, roads, bridges, dams etc. Cement production is a heat-intensive process and causes thermal expansion in duct systems. To compensate this, Indian cement producer Ramco Cement needed fabric expansion joints with a diameter of several meters for two of their plants. On the basis of a close collaboration, EagleBurgmann was able to design components that increase the efficiency of the plant in the long run.

Read the complete case study

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
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.