Guide to Preventive Pump System Maintenance
Many applications depend on pumps operating correctly, and, in certain cases, an unreliable pump can even cause catastrophic damage to a pumping system. For example, a pump in a cooling system that breaks down can cause overheating that then leads to system failure, while in systems that pump lubricants, this can result in the seizing of mechanical implements that then ruin equipment. In other cases, failed pumping mechanisms can cause significant loss in productivity, as would be the case in the petrochemical or energy industries.
Without pumps, many industrial facilities would not be able to operate. As a result, pump systems are often designed to safeguard against system failures, with engineers adding pump capacity via oversized pump systems. As a result, maintenance expenditure increases, as these larger pumps generally use more energy, increasing wear on valves, piping, and other system components. To mitigate problems within pump systems, maintenance that prevents breakdowns from occurring is more efficient than reacting to them.
Types of Pump Systems Maintenance
Pump system design often works from the “best efficiency point,” a strategy that seeks to keep pumping at or as near peak efficiency as possible. Performance declines as components within the pump’s system wear, accelerating issues like cavitation, deteriorating bearings, excessive heat, seal wear, and unwanted vibrations. While the problems often only begin gradually, failure to maintain pump systems adequately can result in costly equipment failure and significant downtime.
The three primary categories of maintenance are:
- Reactive maintenance is done only once problems are noted.
- Preventive maintenance involves scheduled servicing to prevent issues from occurring.
- Predictive maintenance uses monitoring devices and sophisticated software to predict when maintenance is necessary.
When it comes to pumping systems, maintenance is necessary before performance dips too sharply. Not promptly addressing mechanical and other pump performance issues leads to underperforming and inefficient pump systems. Maintenance helps restore a pumping system’s full functionality, keeping performance at or around its highest point.
Reactive Pump Systems Maintenance
Sometimes referred to as corrective or breakdown maintenance, reactive maintenance involves reacting to a failure once it has already occurred. Maintenance personnel may be called upon for minor issues with pump systems, often involving a slowdown or a brief downtime while the issue is being resolved. When it comes to more advanced problems, an outside vendor specializing in pump repair may be needed.
Reactive maintenance for pump systems may occur in situations involving:
- Leaking fluids
- Motor tripping
- Pump stoppage
These situations require urgent action, with each incident potentially costing thousands of dollars in lost production due to unplanned downtime. As such, reactive maintenance is often the most expensive option and should be avoided whenever possible.
Preventive Pump Systems Maintenance
Typically, this involves a maintenance plan or strategy and regularly conducted inspections. These are often done at specified times – such as daily, weekly, monthly, or annual equipment checks – or based on the number of hours equipment has been running. These regular assessments entail brief periods of planned downtime where the pump system is evaluated internally and externally. This will normally involve inspecting seals, gaskets, and other pump parts and replacing them when sufficiently worn.
Generally, preventive pump systems maintenance involves checking the following:
- Barrier fluid: Also known as a mechanical seal, this barrier should be inspected for contamination; this may include checking:
- Excessive fluid temperatures while operating
- Component tolerances: As parts wear, their design tolerances may fall outside acceptable parameters, so a vernier should be used to measure tolerances, including the fit of the bearings at the shaft, outside diameter of the shaft, impeller’s diameter, and casing thickness.
- Corrosion and erosion: Deterioration of components like casing plugs, flanges, impeller, or even the main body of the pump can result from the fluid’s chemical makeup (corrosion) as well as the velocity and flow of the liquid (erosion).
- Differential pressure: This involves calculating differences between the pump’s outlet and inlet pressures to determine the pump’s ability to lift fluids from one level to another, ensuring that it’s operating within normal parameters.
- Gaskets: Surfaces should be checked for irregularities and wear or leaks at the casing.
- High temperatures: This may be a problem with the motor, casing or bearings; cameras designed for thermal imaging can reveal excessive temperatures without requiring a halt to operations.
- Motor: Look at the current being drawn, lubricant levels, whether bearings require renewing, and condition and continuity of windings.
- Vibration: Most commonly caused by bent shafts, contact between parts, and reaction forces affecting fluid pressure, along with misaligned and unbalanced equipment, vibrations must be kept to a minimum and within design limits.
- Noise: Should fall within design parameters, though gravelly, grinding or squealing sounds may indicate a major problem; causes of pump noise might include:
- Cavitation caused by imploding internal gaseous bubbles within the pumped fluid.
- Contaminated lubricant that can cause the pump to knock when the motor starts, stops or changes speed.
- Equipment that’s improperly secured, which causes rattling or banging.
- High flow rates at low pressure can cause noise but no immediate issues.
- Worn cam bearings attached to pump motor or seals that have formed leaks.
For pump systems, maintenance should ideally fall into what’s known as the “6 to 1 rule,” which states the preferred ratio of preventive maintenance to reactive maintenance. This means that one case of reactive maintenance should occur for every six preventive maintenance inspections. Above this ratio means assessments are occurring too frequently, whereas assessments are being made too infrequently below this ratio.
The reason for this ratio is that though preventive pump systems maintenance will help avoid incidents of unplanned downtime and the high costs associated with reactive maintenance, there are high labor costs associated with dismantling complex pump systems. In many cases, maintenance inspections by third-party pump specialists can help keep costs down.
Predictive Pump Systems Maintenance
Regarding pump systems, maintenance is ideal when it contributes to replacing components before failure. It shouldn’t replace parts that have only experienced a fraction of wear. This type of pump maintenance requires monitoring devices that collect data to prevent failure. Modern monitoring systems can achieve an accuracy of up to 95 percent, with the ability to predict failure up to a year in advance.
Monitoring devices for pump systems maintenance should offer capabilities that include:
- Artificial intelligence (AI) helps forecast a pump’s health into the future based on gathered data, enabling better allocation of resources and more accurate repair decisions.
- Data collection across a broad range and at high frequencies to detect abnormalities in equipment early, with more expensive models allowing for longer lead times before predicted failures.
- Real-time reporting that tracks minimum and maximum performance factors like:
- Torque increasing due to motor failure
- Pump blockages and leaks
- Data sampling over long enough lengths to warrant enough time to identify issues.
In predictive maintenance, these features work harmoniously to ensure proactive rather than reactive measures are taken to maintain pump systems. Maintenance done this way also largely eliminates downtime and unnecessary replacement of components that haven’t reached the end of their lifecycle.
Hayes Pump: Systems Maintenance Provider
Hayes Pump Inc. provides 24/7 service for pumps throughout New England (CT, MA, ME, NH, NJ, NY, RI, VT) for emergencies. We additionally offer regular pump maintenance programs to keep your downtime to a minimum, with our professional personnel trained to maintain all sorts of pump systems. Maintenance can also benefit from our predictive solutions for monitoring indicators like lubricant levels, machine speed, pressure, temperatures, and vibrations.
As experts in pump systems maintenance, we understand that this post merely touches the surface. For a more comprehensive guide on maintaining pump systems, here is a link to Improving Pumping System Performance: A Sourcebook for Industry, which was put out by the US Department of Energy (DOE). For answers to any questions about pump systems maintenance – or anything to do with pumps – contact the pump professionals at Hayes today.