Elastomer seals are built to handle a wide range of demanding hydraulic applications, however improper storage conditions can drastically reduce a seal’s potential shelf life. A seal’s design and material properties are crucial to performance, however there are other ways to safekeep seals, allowing storage for a longer period of time prior to installation.
10 Tips for Storing and Cleaning Elastomer Seals
1. Storage period. Shelf life is the storage period after manufacturing and before installation of elastomeric seals. Ideally, elastomer seals should be used within 24 months, however the recommended maximum storage period depends on the type of elastomer. The recommended maximum storage period per ISO and DIN guidelines for the following elastomers is:
Thermoplastic urethane (TPU): 4 years
Hydrogenated nitrile (HNBR), nitrile (NBR) and chloroprene (CR): 6 years
Ethylene propylene (EPDM): 8 years
Fluorocarbon (FKM), silicone (VMQ) and fluorosilicone (FVMQ): 10 years
Perfluorelastomer (FFKM): 13 years
2. Temperature. The preferred storage temperature for elastomer products is 15°C (59°F). Temperature should not exceed 25°C (77°F), and should not drop below -10°C (14°F). At lower temperatures elastomer products will stiffen, so seals should be handled with special care to prevent deformation.
3. Deformation. Seals must be stored without being subjected to strain, stretching (including hanging), twisting or compression, otherwise damage or cracking may result.
4. Humidity. Relative humidity in storage facilities should remain below 65%. Avoid humid rooms and condensation, but also extremely dry conditions.
5. Oxygen. Generally, elastomer seals should be protected against circulating air by suitable packaging, such as airtight containers. This is particularly important for very small seals with a large surface-to-volume ratio.
6. Radiation & light. Elastomer seals must be protected against sources of light with a high UV content that could damage the products, for example direct sunlight and intense artificial light. Additionally, avoid all types of radiation such as radioactive radiation or gamma.
7. Greases/solvents. Greases, oils and solvents may damage elastomer seals. Therefore, it is important to ensure that the seals do not come into contact with these in storage.
8. Contact with other materials. Just as elastomeric seals should not come in contact with liquids like fuels, greases, disinfectants and cleaning fluids, certain metals and alloys should also be avoided (in particular, copper, manganese, and iron) as they are known to damage elastomers. Finally, avoid contact between different elastomers and seals, and materials containing plasticizers (such as PVC).
9. Inspection after storage. Generally, elastomer products should be checked via visual inspection to ensure their proper condition prior to installation. The main characteristics to identify would be dirt deposits, cracks, hardening, softening, stickiness or discoloration. Following an inspection of these characteristics, the recommended maximum storage period may be extended. However, for small elastomer seals the inspection cycles should be shortened due to the greater surface-to-volume ratio and the resulting risk of oxidative attack.
10. Cleaning. Elastomer seals should be cleaned using a clean cloth and lukewarm water. Exceptions are fabric-reinforced elastomer seals which should avoid contact with water. Never use gasoline, benzene, turpentine or similar substances as cleaning fluids. Finally, avoid contact with sharp-edged or pointed objects such as steel brushes or sanding paper, and do not dry elastomer seals near radiators.
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