How Do Rotary Seals Work?

Rotary Seals are used primarily in high-pressure applications – specifically lubricant rotating control devices. They work by pushing the lubricant into the lip and shaft. This sealing is helped by the hydrodynamic action caused by the rotating shaft’s pump-like actions.

The shaft seals actually provide a good amount of protection, aiming to retain the bearings and lubricant. The seal works both ways, and can also exclude materials that could potentially damage or contaminate the system lubricant.

Depending on the application it’s used for, some of the common contamination types include water or moisture buildup, dust and even sand or grit. These can greatly affect the system, especially if the work conditions are dirty.


Essentially, the stronger your seal’s ability to maintain system lubricant, the longer your service life will be for those pieces of equipment. Not only can the seal reduce exposure to harmful materials, but it can prevent friction heat if the rotary shaft device is running at high speeds. This sliding movement contacted between lip and shaft seal does create friction heat, which over time will lead to corrosion and breakdown.

It is important to note that the heat generated depends on lots of factors, anything from your shaft surface to speed, pressure, and lubricant type. A sudden rise in temperature can increase pressure inside the casing.

What Are The Important Factors?

Some of the most important aspects to consider if you’re thinking of choosing a rotary seal would be how much frictional heat it can maintain, compression amount, operation temperature limits, and of course the shaft itself.

Due to the extremely low friction properties of rotary seals, they are built to last in many difficult rotational process scenarios.

Hopefully, this blog gave you some insight on how rotary seals actually work, and if you enjoyed the read, please feel free to check out some of our other blogs here: https://www.beldamcrossley.co.uk/blog/

Alternatively, you can contact us for any questions or more information! https://www.beldamcrossley.co.uk/contact/