Ready to cut your maintenance costs and eliminate downtime nightmares?
Every plant relies on smooth-running equipment to avoid halting production. Breakdowns are costly no matter where they occur in the operation. But here’s the punchline…
Unplanned downtime costs average $260,000 per hour according to the Aberdeen Group. We’re sure that will make the hair on the back of your neck stand up.
The good news?
All of these unexpected failures are entirely preventable with the right maintenance strategy. Piston pumps can last 40 years or more when properly maintained. Neglect them, and you’ll pay in spades.
In this guide, you will find:
- Piston Pump 101
- Four Failure Modes
- Maintenance Methods
- Troubleshooting
- Maintenance Schedule
Piston Pump 101
We’ve got a confession to make…
Piston pumps are different than the centrifugal pumps used to move liquids around. These precision pieces of equipment need to be maintained meticulously.
Centrifugal pumps can be abused and still work. On the other hand, positive displacement piston pumps must have no slop in the system. Piston pumps are precision machines that need to be treated as such. They create flow by moving liquids from a suction port into an inlet check valve, which is closed by an outlet check valve, and finally into a discharge check valve as they recede. The most important thing to remember is all components must work flawlessly for optimal performance.
Here’s another tip…
Reliability and efficiency are what make piston pumps a great choice for your operation. They easily handle high-pressure applications while providing consistent flowrates no matter how much system pressure varies. If your application requires precision, piston pumps are a must.
Four Failure Modes
Here’s a fun fact…
Industry statistics indicate that four failure modes account for over 90% of piston pump breakdowns. If you can master the following four failure modes, you can extend the life of your equipment exponentially:
Oil Contamination
Oil contamination is the number one enemy of piston pumps. Once contaminated, oil can cause:
- Valve plate scoring, which reduces pump efficiency.
- Vertical scratches on the piston barrel.
- Excessive wear on saddle bearings.
- Plugged orifices leading to restricted flow.
- Piston seizure inside the cylinder bore.
The fix? Make sure you have a comprehensive oil analysis program in place and keep your hydraulic systems immaculate.
Pressure Spike Fatigue
These milliseconds-long pressure spikes will destroy your pumps. Broken pistons, shaft failures, and damaged yokes with cracks in the cylinder barrel are all from pressure spike fatigue events. The number one problem? You’ll never see pressure spikes without special monitoring equipment because they last a fraction of a second.
Blocked Inlet Conditions
Pumps that are starving for flow won’t last long. Here are some of the most common reasons for blocked inlet conditions and what they lead to:
- Cavitation damage on valve plates
- The dreaded “marble sound” while running
- Vapor-filled voids that collapse and cause erosion
- Accelerated wear and tear all around
Case Over-Pressurization
Cases that experience over-pressurization will fail quickly. This can be the result of blocked drain lines or incorrect system design.
Maintenance Methods
Here’s what we love the most about Piston pump maintenance:
If you have the correct plan in place, you can predict when maintenance is required. It’s completely predictable and straightforward. Here’s how to do it:
Preventive Maintenance Scheduling
Plan maintenance activities based on the hours of operation rather than on a calendar date. For example, a pump running continuously will require different service levels than one running only part-time.
Typical maintenance tasks include:
- Scheduled oil sampling and analysis
- Seal inspections and replacements
- Timing checks on valves
- Pressure adjustments
- Vibration monitoring
Condition Based Monitoring
Condition-based monitoring using sensors that detect early warning signs of potential problems. This includes:
- Vibration analysis to detect bearing wear
- Temperature changes to identify friction issues
- Pressure monitoring to reveal valve problems
- Oil analysis trending to identify contamination
Proactive Replacement
Don’t wait for equipment failure before replacing components. Be proactive and change them out on a regular schedule based on:
- Manufacturer recommendations
- Severity of operating conditions
- Historical performance trends
- Predictive maintenance data
Troubleshooting
Here’s the fastest way to troubleshoot piston pump problems:
Problem: Reduced Flow Rate
- Inspect piston rings for wear that could cause internal leakage.
- Check check valves for damage that could prevent proper sealing.
- Verify valve timing is correct for efficient pump operation.
- Ensure system pressure does not exceed the pump’s capabilities.
Problem: Excessive Noise
- Investigate cavitation due to inadequate inlet conditions.
- Check bearings for wear that could cause mechanical noise.
- Inspect mounting for looseness that could cause vibration.
- Examine internal components for damage.
Problem: Overheating
- Confirm adequate lubrication to reduce friction.
- Check system pressure, as excessive pressure can cause heat.
- Ensure good ventilation around the pump housing.
- Inspect for internal leakage, which can increase energy use.
Problem: Erratic Pressure
- Check for air entrainment in the hydraulic system.
- Inspect pump internals for wear that could cause bypass.
- Test the pressure relief valve for proper operation.
- Monitor system contamination, which can affect valve function.
Maintenance Schedule
Research indicates that eighty percent of companies that connect to computerized maintenance management systems experience an increase in productivity. Let’s look at a maintenance schedule:
Daily
- Visual leak inspection
- Verify normal operating temperatures
- Check for unusual noises
- Read pressure gauges
Weekly
- Check oil level and condition
- Inspect and clean filters
- Confirm belt tension is correct
- Check coupling alignment
Monthly
- Perform vibration analysis
- Take oil samples
- Assess seal condition
- Test system pressure
Quarterly
- Disassemble and inspect the entire pump
- Replace any worn components
- Measure and record clearances for precision
- Conduct performance tests and calibration
Maximizing Equipment Life
Maintenance methods don’t stop at the fundamentals; there are advanced techniques to consider as well. Here are some tips to help you get the most life out of your equipment:
Always use quality replacement parts. Cheap parts have been found to cost more over the long haul, not just through reduced reliability but also because they typically have shorter service intervals.
Train your maintenance staff. The right maintenance procedures are vital. Using your regular maintenance team is good, but only if they are trained properly on pump-specific procedures. Piston pumps have different requirements than general mechanical equipment, so ensure your team has specialized knowledge.
Document and optimize. Accurate records can help determine patterns and help refine maintenance intervals for greater efficiency. What gets measured, gets managed.
Buy the right tools for the job. Precision assembly and measuring tools are needed for accurate tolerances. Basic tools just won’t do.
Putting it All Together
The secret sauce of plants with excellent maintenance programs isn’t complicated – they just follow the same successful maintenance strategies year after year. What’s equally important is your perspective.
Don’t think about maintenance as an expense; think of it as an investment in your business. Maintenance provides a return on your investment, by preventing catastrophic failures and keeping your plant running reliably and safely. In fact, according to industry research, the purchase price is only 10% of total life cycle costs for any equipment. Energy consumption is the largest component of life cycle costs at 40%, and maintenance accounts for another 25% of total expenses.
Preventive maintenance isn’t complicated, and it’s a long-term payback. The places to start are the basics like clean oil and proper lubrication, regular inspections, and timely repairs. From there, many plants have enhanced their maintenance programs by adding condition monitoring, analysis, and other predictive maintenance technologies. However, don’t get too far ahead of yourself.
The worst thing you can do is wait until your pumps start making noise or giving other symptoms of failure. By the time that happens, a lot of expensive damage has already occurred. So don’t wait; prevention is always less costly than the cure.
