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Installation tips

Important considerations for correctly fitting seals

Seals are vital for keeping your machinery protected from external environmental conditions and contamination as well as keeping lubricant or media in the system. However, if you perform installation incorrectly, this can lead to a host of problems throughout a seal’s service life. Here, I provide some key insights into how to install them correctly.

So, what’s the first thing to consider when mounting your seals? For me, the first factor actually comes before you start installation. Depending on how your seals were stored affects how effective they will be when in operation. If they have been stored in poor conditions, they could already be contaminated or damaged. This means that your seals could be defective before they’ve entered operation – making the installation process pointless, as it must be repeated. I advise ensuring that your warehouse is clean and suitable for storage. If excessive moisture, UV irradiation, grit, or solvents are present, for example, you’re likely to have a problem. Additionally, you should check before installation that your seals have been properly packaged.

All seals and applications are different and have different demands. However, basic preparation and adherence to best practices set you up for success.

Heimo Rehschützecker

My second key consideration is lubrication. I often hear that clients are having trouble fitting their seals. This is frequently due to inadequate lubrication. In fact, I’ve even come across seals being damaged or completely destroyed as a result. As is the case with poor storage, inadequately lubricated seals can be defective before they are used in the application. I advise wiping the shaft and seal with the lubricant that is to be retained. However, make sure that you use a lubricant that is compatible with your seal material. This is also key for avoiding premature damage.  

The variety of common sealing materials show completely different installation behavior. Metal cased seals or PTFE compounds, for example, have very limited or no elasticity. This typically demands either open accessible housings or the use of special mounting tools. Rubber compounds and thermoplastic polyurethane elastomers show much better elasticity and can therefore more easily be snapped into seal housing grooves or stretched into piston housings. As an example, a hydraulic rod seal made of polyurethane can normally be easily mounted by hand, except if the cross-section of the seal in comparison to its diameter is too large. In such cases, mounting tools are recommended. In this context, it also could be helpful to carefully warm up the seal (ideally in the media to be sealed in order to assure compatibility). 

For some applications, split seals can be designed to avoid installation issues. Such solutions are typically used on larger, heavyduty equipment to avoid long periods of downtime. For these seals, special mounting instructions are available. 

My final tip for rotary shaft seals is to also consider the usage of wear sleeves to provide an optimized counter surface for the seal. When mounting these wear sleeves, special mounting tools and instructions are available.  

In general, instruction manuals, including health and safety aspects, will provide you with the information you need when it comes to seal installation and should be read in depth before beginning any work. 

And these are my simple tips for installing seals correctly. What’s your experience with this? Maybe you have some experience of your own. Let us know your findings in the comments section below.  

Author: Heimo Rehschützecker