Case Study: Increasing Centrifugal Pumps Reliability by Redesign of Critical Spare Parts

Abstract Machinery Reliability is a built-in feature dictated by its original design. Once a brand-new machine is in service and exposed to its service conditions, maintenance efforts cannot improve Reliability, but instead, only maintain the asset up to its originally designed Reliability level. For assets facing frequent failures, additional maintenance efforts can be implemented to support the asset availability and try to increase as much as possible the uptime, however, the original low reliability cannot be addressed unless a redesign is performed. This case study is related to centrifugal pumps (API, multi-stage, vertically suspended) facing premature failures since commissioning and the steps taken to significantly improve the pump's inherent reliability by the redesign of some internal components. As initial approach the pump's OEM (Original Equipment Manufacturer) was consulted to sort out a technical solution. Several trials were conducted with OEM guidance without any measurable benefit. Due to the failure of the first approach, a formal RCA was initiated to understand the failure mechanism and identify a list of feasible and cost-effective solutions. Centrifugal pumps redesign is a feasible solution to extend the expected life. This paper shows details of the critical spare parts selected for a redesign, including varied materials of fabrication, upgraded materials surface treatments and changes on spare parts shape/dimensions. Results obtained after several trials showed a significant extension of pump life (Mean Time Between Failures was extended up to twenty times), lower spare parts cost and lower overall maintenance cost for thirty centrifugal pumps. The results show how the redesign of critical spare parts can increase the pumps original Reliability and at the same time, offer cost-effective solutions with significant improvements in the asset availability (machinery uptime, higher production rates) and cost savings in OPEX budget (lower maintenance cost in the long-term). Similar studies can be conducted at other Oil & Gas operators where similar challenges could be affecting the company goals in terms of availability, production, or maintenance cost.