A seal that leaks after cleaning or sterilising may be telling you about a duty the original specification missed. The seal sees more than the product. It also sees the wash chemicals, rinse, hot water or steam, followed by cooling and sometimes vacuum. Those changes can affect both the elastomer and the seal faces.
First note exactly when the leak begins: during the hot stage, during cool down, or when the pump restarts. Check the actual chemical concentration, time, peak temperature and number of cycles. Look for a secondary seal that has swollen, hardened or taken a permanent set. Check the faces and support system too. A leak after CIP is not automatically an elastomer problem.
Do not sign off a substitute because the material family says EPDM or FFKM. Ask for the actual compound grade and evidence for the whole cycle, including the cleaning chemical and steam. If the process changed, update the seal specification and the maintenance record so the next replacement does not repeat the mistake.
Andrew Sykes | Acumen Seals & Pumps Limited | Independent mechanical seals and sealing specialist