Choosing the right rubber seal is crucial for reliable pump operation. During overhaul and maintenance projects, we regularly see that the wrong choice of material leads to leaks, chemical corrosion, or premature wear. Viton® FPM, EPDM, and NBR are the most commonly used elastomers, but each material has specific properties and limitations. In this article, we explain when to choose which type and when not to.
Seals prevent fluid from escaping past rotating or stationary parts. They must also be resistant to the medium, temperature, and mechanical stress. The right choice directly determines the service life of bearings, mechanical seals, and pump housings. Errors in material selection are one of the most common causes of unwanted overhauls.
NBR is the most commonly used sealing material in industrial pumps. It offers a good balance between cost, chemical resistance, and wear resistance.
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\n\n\n\nIn overhaul work, we often see that NBR is used where there is actually only light chemical exposure. This leads to hardening or cracking, resulting in leakage.
EPDM is highly resistant to water, steam, and many chemicals. It is widely used in process installations, irrigation systems, and pumps that handle more aggressive water.
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\n\n\n\nEPDM is sometimes incorrectly chosen for systems containing lubricants or oil-containing products. This causes rapid swelling and loss of elastic properties.
Viton is a fluoroelastomer with high chemical and thermal resistance. It is used where standard rubbers fail due to aggressive media or high temperatures.
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\n\n\n\nIn practice, Viton® FPM is sometimes seen as “always better,” but that is not true. In hot-water pumps or steam applications, EPDM actually performs better than Viton.
Every application requires a suitable solution. Is your question not addressed in this article, or would you like to discuss your specific situation? Please contact one of our specialists. We are happy to assist you with expert advice and practical support.
No, Viton® FPM isn’t always the best choice. In applications involving water and steam, Viton® FPM can degrade relatively quickly, making the seal less reliable. In such situations, EPDM is often a more suitable alternative.
No, EPDM is not suitable for all water applications. The material performs well with water and steam, but is less resistant to oils, greases, and fuels in the medium.
No, NBR is versatile, but not universal. With certain chemicals and aggressive media, chemical degradation can occur more quickly than is often assumed.