A Validated Industrial Case Study Demonstrates a Practical Maintenance Intervention for Centrifugal Pump Mechanical Seals Under Supply-Chain Constraints

Mechanical seal failure is a significant cause of unplanned downtime in centrifugal pumps used in large water and process industries, particularly where reliance on imported original equipment manufacturer (OEM) spare parts results in extended procurement lead times. This paper presents an industrial case study on the emergency in-situ restoration of a damaged stationary ceramics mechanical seal face in an ultrafiltration (UF) backwash pump (Tag: 50-P-007B, capacity 1100 m³/hr) at Dangote Fertiliser Limited, Nigeria. Following seal face chipping and the unavailability of replacement components with OEM lead times of 6–18 weeks, an epoxy-based composite material (M-Seal) was used as a contingency repair. The repair methodology involved controlled surface preparation, epoxy composite application to rebuild the sealing interface, finishing to restore functional flatness, and a monitored 24-hour curing period before recommissioning. On start-up, leakage ceased completely within minutes of operation. The pump was subsequently monitored under normal UF backwash operating conditions. Field evidence confirms that the repaired seal remained in continuous service for over four years without observable leakage, abnormal wear, or performance degradation. A comparative economic assessment indicates substantial reductions in downtime duration and maintenance cost relative to OEM seal replacement. The study demonstrates that controlled epoxy-based restoration of stationary mechanical seal faces can provide a reliable and cost-effective contingency maintenance strategy for benign water-based services, enhancing equipment availability and operational resilience under supply-chain constraints.