Shaft seals are inconspicuous yet essential components in mechanical engineering. They are used in gearboxes, pumps and electric motors and are applied by companies in industries such as chemical processing, mechanical and pump engineering, as well as automotive and agricultural machinery manufacturing.

Shaft seals are the silent workers in the background – invisible, yet critically important. Their task is to retain oil and grease within the system while preventing dirt, dust, contaminants and water from entering, ensuring that machines continue to operate smoothly and reliably.

Components

Other common terms for shaft seals are “radial shaft seals” or “Simmerrings”. They consist of a metal casing and an elastomer sealing lip, also referred to as the sealing edge. This flexible sealing lip is in contact with the rotating shaft.

Selecting the Right Seal

Choosing the correct shaft seal depends on various criteria, including rotational speed, temperature and the media involved. These factors determine which material the sealing lip must be made of.

Different Sealing Lip Materials

NBR Seals

NBR seals (Nitrile Butadiene Rubber) are synthetic elastomer seals. They are the standard solution for many applications. They offer good mechanical properties and reliable resistance to grease and oils. They are cost-effective and ideal for use in gearboxes, mechanical engineering and hydraulic systems. Operating range up to approx. 100 °C, short-term up to approx. 120 °C.

FKM Seals

FKM seals (Fluoroelastomer), often known under the brand name Viton®, are shaft seals mainly used in the chemical industry, automotive engineering and high-performance machinery. These seals are used whenever the properties of PTFE and NBR are insufficient. They withstand continuous temperatures up to 200 °C and offer excellent service life as well as high chemical resistance. In addition, they feature low gas permeability.

PTFE Seals

PTFE seals (Polytetrafluoroethylene), often known under the brand name Teflon®, represent the high-end solution. Shaft seals made from this material perform exceptionally well even under extreme conditions. They are self-lubricating and highly suitable for applications with low friction coefficients. They also provide excellent sealing performance and are resistant to almost all chemicals, oils and aggressive media. Additional key advantages: they can operate under dry-running conditions and withstand temperatures up to 200 °C, and even up to 300 °C for short periods.

Application Characteristics

• Oil and grease: NBR
• Chemicals: FKM or PTFE
• Water and steam: EPDM
• Rotational speeds (standard): NBR
• Rotational speeds (high): FKM or PTFE

Temperatures

• Standard: NBR
• High: FKM
• Extreme: PTFE

Delivery Quantities

Shaft seals can already be ordered from a quantity of one piece via the poesia-group webshop of herzog dichtungen ag: https://shop.herzog-dichtungen.ch/de

Delivery Times

Most dimensions are available from stock at poesia-group, enabling short delivery times.

Conclusion

The shaft seals of the poesia-group ensure that machines operate cleanly and reliably. It is particularly important to determine which properties the shaft seal must fulfil so that it can perform its function perfectly. Therefore, it is essential to clarify the machine specifications accurately in order to make the correct selection. The seal must always be matched to the specific application and machine type. The right combination of design and material determines whether a machine operates efficiently, leak-tight and with a long service life.

• NBR: economical and proven
• FKM: high-performance and temperature-resistant
• PTFE: extremely durable and versatile

For all questions regarding shaft seals, the specialists of the poesia-group are happy to assist.