Water is an important resource commonly used in industrial cooling processes and other non API applications. Vertical pumps are commonly used due to their reliability in design. Vertical pumps are essential equipment for transporting high flow water in the entire water, petrochemical, and power generation industries. By optimizing the performance and efficiency of these important pumps, operating and maintenance costs can be significantly reduced.
1. Performance matching
Vertical pumps are easily overlooked during daily maintenance. The reliability of their design means that they are rarely affected by attention grabbing situations. However, over time, the wear and tear of various components can lead to a gradual decrease in efficiency, which may worsen if not properly maintained.
Maintaining hydraulic design for application conditions is crucial for the reliability and performance of pumps. Operating within the tolerance zone on either side of the best efficiency point (BEP) of the pump can increase its ability to withstand faults. Staying away from this area can lead to increased vibration, shortened bearing life, shortened mechanical seal life, increased random failures, and overall shortened pump life.
2. Adapt to constantly changing requirements
A common situation encountered is that the pump has been in use for many years, but during this period, the application situation has changed. For example, the flow rate is usually reduced by using a control valve downstream of the pump. This means that the pump can operate at less than 50% of its design flow rate, which increases operating costs and affects the service life of the control valve. Even worse, any loss in pump performance goes unnoticed; The operator may slightly open the control valve for compensation.
The solution is to adjust the hydraulic parameters of the pump to better match the modified application. This allows the control valve to be used for its intended purpose, rather than as a flow restrictor, and the pump can operate near its BEP. However, making a single change (such as trimming the impeller) may achieve an expected result, but it may also bring other challenges, so careful analysis is needed.
3. Ensure minimum flow rate
Another common issue encountered is focused around the system to maintain a minimum flow rate at the pump inlet. Circulating valves are used to ensure minimum continuous stable flow to protect the pump from low flow damage, but all water flowing through these valves is equivalent to waste. What makes this issue even more complex is that these systems are often set up incorrectly, and over time, this relatively small problem can have significant consequences, such as cavitation damage to the impeller.
The operator can replace the circulation valve, but does not have the knowledge or ability to ensure correct installation and setting. Since then, pumps that should have been protected may experience accelerated wear and tear.
4. New parts
Obviously, after years of use, pump components will wear out and eventually need to be replaced. At this point, it is important to understand the difference between recycled parts and redesigned parts, as well as how advances in materials, design analysis, and manufacturing processes enable new parts to provide higher performance and reliability.
Merely regenerating existing parts can lead to reduced efficiency, premature failure of bearings and seals, and increased vibration. The reason for these problems may be the lack of design engineering means, which means that new dimensions cannot be achieved, surface smoothness is lower than the standard, and gaps are not ideal.
By using the original parts as a starting point and applying current engineering standards to enhance the design, new parts with the best hydraulic model can be created. Minor modifications can also make improved bearing and seal designs a part of the project, thereby extending service life and reducing maintenance costs.
5. Bearings
The design of vertical pumps relies on good bearing design to achieve sustained performance. Therefore, it is necessary to fully understand the options for materials and lubrication systems to ensure the installation of the most suitable system. By matching the bearing design with the application, the service life of the pump can be extended and maintenance costs can be minimized.
In many cases, the wear of the bearing system determines the maintenance plan of the pump, so the choices made at this time will have a significant impact on the future. The use of composite materials helps prevent dry running and provides better wear resistance and corrosion resistance.
Each application has an optimal bearing design, including the lubrication technology used. In some cases, it is more suitable to use the bearing tube shell, while in other cases, the performance of lubricating the bearing with the product is better. It is important to understand the advantages of each system and collaborate with pump design experts to provide recommendations on the most suitable system.
6. Sealing system
When dealing with bearings, the sealing system must also be considered. Although packing has always been the main design in the past, it still holds a place in modern sealing systems. If maintained properly, it can complement the bearings, provide additional support, and help suppress vibrations.
Meanwhile, depending on the application, mechanical seals also have their place.
Correctly reinstalling the pump after completing the maintenance project is crucial for sustained reliability. The correct alignment of a vertical pump is one of the most important aspects in any maintenance procedure. This applies to the base plate and intermediate bearings. Assembly and installation procedures must be completed very carefully, otherwise the slightest deviation along the length of the pump may occur, which may significantly shorten the service life.
