Effective Methods to Enhance the Efficiency and Reliability of Vertical Pumps

Effective Methods to Enhance the Efficiency and Reliability of Vertical Pumps

Anhui Shengshi Datang will now give you a science popularization.Water is an important resource, commonly used in industrial cooling processes and other non-API applications. Due to their reliable design, vertical pumps are widely utilized. They are essential equipment in the water, petrochemical, and power generation industries for transporting large volumes of water. By optimizing the performance and efficiency of these critical pumps, operational and maintenance costs can be significantly reduced.

Performance Matching

Vertical pumps are often overlooked during routine maintenance. Their reliable design means they rarely attract attention under normal circumstances. However, over time, wear and tear on various components can gradually reduce efficiency, and without proper maintenance, this decline can accelerate.

Maintaining the hydraulic design conditions of the application is crucial for the pump's reliability and performance. Operating within the tolerance band on either side of the pump's Best Efficiency Point (BEP) enhances fault resistance. Operating outside this range can lead to increased vibration, reduced bearing life, shortened mechanical seal life, more frequent random failures, and an overall decrease in the pump's lifespan.

Adapting to Changing Requirements

A common scenario is that a pump has been in use for many years, but during this time, the application conditions have changed. For example, flow rates are often reduced by using control valves downstream of the pump. This means the pump may operate at as low as 50% of its designed flow rate, increasing operational costs and affecting the control valve's lifespan. Worse still, any loss in pump performance may go unnoticed; operators might simply open the control valve slightly to compensate.

The solution is to adjust the pump's hydraulic parameters to better match the modified application. This allows the control valve to serve its intended purpose rather than acting as a flow restrictor, and enables the pump to operate near its BEP. However, making a single change, such as trimming the impeller, might achieve the desired outcome but could also introduce other challenges, requiring careful analysis.

Ensuring Minimum Flow

Another common issue revolves around systems designed to maintain a minimum flow rate at the pump inlet. Recirculation valves are used to ensure the minimum continuous stable flow, protecting the pump from low-flow damage. However, all water flowing through these valves represents wasted energy. Compounding this issue, these systems are often improperly configured. Over time, this seemingly minor problem can lead to significant consequences, such as cavitation damage to the impeller.

Operators may replace recirculation valves but lack the knowledge or capability to ensure proper installation and setup. From that point onward, the pump, which was meant to be protected, may experience accelerated wear.

New Components

Clearly, after years of use, pump components will wear out and eventually need replacement. At this point, it is important to understand the difference between refurbished parts and redesigned parts, as well as how advancements in materials, design analysis, and manufacturing processes enable new components to deliver higher performance and reliability.

Simply refurbishing existing parts can lead to reduced efficiency, premature bearing and seal failures, and increased vibration. These issues may arise due to a lack of design engineering, resulting in failure to achieve new dimensions, substandard surface finishes, and non-optimal clearances.

By using original parts as a starting point and applying current engineering standards to enhance the design, new components with optimized hydraulic models can be created. Minor modifications can also incorporate improved bearing and seal designs as part of the project, extending service life and reducing maintenance costs.

Bearings

The design of vertical pumps relies on robust bearing design for sustained performance. Therefore, it is essential to fully understand the options in terms of materials and lubrication systems to ensure the most suitable system is installed. By matching the bearing design to the application, the pump's lifespan can be extended, and maintenance costs minimized.

In many cases, the wear on the bearing system dictates the pump's maintenance schedule, so the choices made at this stage have significant future implications. Utilizing composite materials can help prevent dry running and provide better wear resistance and corrosion resistance.

Each application has an optimal bearing design, including the lubrication technology employed. Some situations are better suited for bearing housing systems, while others perform better with product-lubricated bearings. It is important to understand the advantages of each system and collaborate with pump design experts to recommend the most suitable solution.

Sealing Systems

When addressing bearings, the sealing system must also be considered. While packing has been a traditional design, it still has a place in modern sealing systems. If properly maintained, it can complement bearings by providing additional support and helping to dampen vibration.

At the same time, mechanical seals have their place depending on the application, and innovative technologies such as Sulzer's Liqui-Seal can offer significant advantages, especially for water-cooled pumps.

After completing maintenance work, proper reinstallation of the pump is critical for ongoing reliability. Correct alignment of vertical pumps is one of the most important aspects of any maintenance procedure. This applies to both the baseplate and intermediate bearings. Assembly and installation procedures must be carried out with extreme care. Even the slightest misalignment along the pump's length can lead to a significant reduction in service life.