Gene Vogel
Pump & Vibration Specialist
Electrical Apparatus Service Association
St. Louis, MO
In his presentation at the EASA Convention 2015, Gene Vogel addresses the critical factors affecting pump reliability, emphasizing the importance of proper application, assembly, and installation. Vogel outlines how neglecting these factors can lead to frequent pump failures, particularly in seals and bearings, which are the most sensitive components of a pump.
Vogel begins by discussing the significance of selecting the right pump for the job. Unlike electric motors, which can operate efficiently even when oversized, pumps must be precisely matched to the pressure and flow rate requirements of the application. Misapplication can result in cavitation, vibration, and erosion, all of which damage pump components and reduce reliability. Cavitation, in particular, occurs when suction pressure is too low, allowing vapor bubbles to form and implode, causing vibration and erosion.
The assembly of pumps is another crucial factor. Vogel highlights the precision required in assembling bearings and seals, noting that casting dimensions can vary significantly, while bearing journals and seal faces must adhere to extremely tight tolerances. Maintaining these tolerances, ensuring cleanliness, and following proper assembly procedures are essential for pump reliability.
Installation factors include the proper alignment of shafts, the support and configuration of piping, and the environmental effects on the pump. Misalignment and improper piping can introduce strains that distort bearing and seal alignment, increasing vibration levels and leading to premature failure. Vogel emphasizes the importance of ongoing maintenance, including inspection, monitoring, and lubrication.
Vogel also discusses the different types of pumps, including positive displacement and dynamic pumps, and their respective advantages and disadvantages. Positive displacement pumps provide constant flow rates and are self-priming, while dynamic pumps, such as centrifugal pumps, have flow rates that depend on system resistance and require external check valves to prevent backflow.
The presentation covers various pump configurations, such as end suction, in-line, close-coupled, submersible, vertical turbine, and double suction pumps. Vogel explains the principles of fluid mechanics, including capacity, pressure, specific gravity, power, efficiency, and viscosity, and how these parameters affect pump performance.
Pump curves are essential tools for understanding the relationship between flow rate and head, and Vogel explains how to interpret these curves to diagnose and troubleshoot pump issues. He also discusses the importance of operating pumps at or near their best efficiency point (BEP) to minimize radial load and vibration.
Vogel concludes by emphasizing the need for performance matching and testing to ensure pumps are properly engineered for their applications. Techniques such as trimming impellers, using variable speed drives, installing accumulators, and providing bypass systems can help match pump performance to system demands, improving efficiency and reliability.
Key Points Covered:
- Importance of proper pump application, assembly, and installation
- Effects of cavitation, vibration, and erosion on pump reliability
- Precision required in assembling bearings and seals
- Different types of pumps and their configurations
- Principles of fluid mechanics and their impact on pump performance
- Interpreting pump curves and operating at the best efficiency point (BEP)
- Techniques for performance matching and testing
Key Takeaways:
- Proper application, assembly, and installation are crucial for pump reliability
- Cavitation, vibration, and erosion can significantly damage pump components
- Precision in assembly and cleanliness are essential for maintaining tolerances
- Understanding pump types and configurations helps in selecting the right pump
- Fluid mechanics principles are key to diagnosing and troubleshooting pump issues
- Operating at or near the BEP minimizes radial load and vibration
- Performance matching and testing ensure pumps are engineered for their applications
Print
