The Danger of DIY Inspection Screens
Missed Inspection Screen Causes $1.2 Million in Damage and Downtime
A flushing provider accidentally left a flange slip screen in place at the conclusion of a flush. The screen became plugged with contamination and starved the turbines HP T5 bearing of oil, causing $1.2 million in damage and downtime.
Easy-to-Spot Screens Could Have Prevented This Loss
Risk of serious system damage can be avoided by using easy to identify slip screens – like the ones sold at www.flushingscreens.com – and comprehensive procedures that list inspection points and require operator verification of removal.
A Turbine Turnaround with Costly Results
During a power generation plant start up activities the Steam Turbine tripped due to high vibration on the HP bearing. Disassembly and inspection of the bearing showed the HP T5 bearing had been wiped and a fine mesh screen installed on the orifice strainer, resulting in oil starvation to the bearing, and subsequent failure.
The fine mesh screen was installed in the T5 bearing orifice strainer during required turnaround flushing activities and was not removed prior to startup. The checklist for tracking fine mesh screens included only LP train T1-T6 and HP train T1 and T2. A final check of the T5 bearing orifice strainer was only for orientation. It was not expected that a fine mesh strainer was installed, and flange slip screen fine mesh screens can be difficult to identify visually.
Immediate actions that were taken, included:
- The T5 bearing was shipped to vendor to be re-spun
- The Turning Gear and T5 oil deflectors were shipped to vendor to be re-toothed
- The H2 seal casing required replacement
This event resulted in significant cost due to rework and repair of the T5 bearing, both oil deflectors and the H2 seal casing. The outage was delayed by 14 days.
The estimated total cost of poor quality (COPQ) for this event was $1,200,000.
How this Could Have Been Avoided
- Inclusion of a reinstatement checklist and verification signatures utilized in tracking removal of oil flushing inspection screens in every flushing activity
- Using easily identifiable flushing screens from flushingscreens.com that have obvious, brightly colored handles that are easily seen
- Performing a final walk through with OEM and a site representative when completing flushing activities
A Better Tool for Verifying API 614 Criteria Are Met
Never mistake your inspection screens for gaskets again! Screens fabricated in house can be mistaken for standard gaskets. Screens left in a system can eventually plug and starve the critical component from receiving necessary flow. With our custom handles it allows for easy identification, storage, installation, and removal. Purchase screens today at www.flushingscreens.com or call 800.770.4510
