All mechanical seals leak to some extent, but the leakage should be kept to a minimum to avoid costly breakdowns. However, even minimal leakage may cause problems over time, especially for continuous-duty pumps and mixers. Accumulated leakage may require costly service actions, such as emptying the inspection chamber or the stator housing. In the worst case, it may cause motor or bearing failure. Preventing leakage into the drive unit increases sealing reliability and minimizes the risk for such service actions. The patented Active Seal functionality from Flygt does just that.