When it Comes to Pump Problems, Treat the Causes, Not Symptoms

Experience shows that thorough investigation of pumping issues leads to long-lasting and cost-effective solutions.
When it Comes to Pump Problems, Treat the Causes, Not Symptoms
Graph indicates high frequency vibration, an indication of potential cavitation.

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A woman’s foot was killing her. She was an avid runner, but a sharp pain in her arch was keeping her away from the sport she loved.

The first two doctors she visited immediately zeroed in on the point of pain. “Let’s give you a cortisone shot,” offered Doctor 1. Doctor 2’s advice: “Put orthotics in your shoes and your arch won’t hurt so much.”

Doctor 3 offered a different solution: “Your foot isn’t the problem. It’s your posture.” A week after taking Doctor 3’s prescription, her foot pain disappeared.

What does a woman’s foot problem have to do with your treatment plant’s maintenance problems? In both cases, the focus too often is on the symptom, not the cause.

The Hydraulic Institute (HI) supports initiatives that can help facility operators get quickly to the root of pump problems and resolve them cost-effectively.

What’s that noise?

A recent event at a wastewater pump station in Pennsylvania illustrates perfectly. The pump system moves wastewater from a storage tank (wet well) to a discharge point at a gravity sewer a long distance from the pump station.

Two pumps are used most of time, pumping through a low-head force main. Three additional pumps are activated during high flows. These pumps discharge into a high-head force main with several high points and low points, traversing 11,000 feet to the gravity sewer.

But the system had a problem: When the high-head pumps kicked on, they occasionally emitted strange noises and vibrations. The maintenance team had some ideas about the cause of the intermittent problem, but their unanswered questions might sound familiar:

  • What’s wrong with these pumps?
  • Under what running conditions are they emitting these unsettling sounds?
  • What’s causing the problem?
  • How can we fix it?

Thorough investigation

ANSI/HI 9.6.5 Rotodynamic Pumps – Guideline for Condition Monitoring is an industry guideline developed by the Hydraulic Institute that can be used to help prevent critical pump and system failures before they occur.

The guideline specifies means of monitoring power, temperature, corrosion, leakage, pressure, vibration, periodic lubricant, shaft position, rate of flow, speed, bearing wear and other parameters. It also provides information on condition monitoring failure modes, indicators, vibration analysis, condition-based maintenance and a preinstallation hydrostatic test.

The guideline educates engineers and maintenance professionals on what type of monitoring and at what interval is appropriate to identify the cause of failure, or to predict failure, thus allowing for scheduled maintenance.

Since the pumps in the example were critical assets for which failures were costly, and because the failures were somewhat random, the guideline recommended that the appropriate monitoring equipment be installed, that data be monitored continuously and that an alarm indication be provided based on set operating parameters. Based on the recommendations of the guideline, the group needed to answer:

  • What data is appropriate to gather and with what type of instrumentation?
  • How can we monitor these pumps 24/7 and document the problem right when it happens?
  • How can we test various solutions without tearing apart the whole system?
  • What is the root cause of this problem?

Cost-saving approach

Based on the failure modes and indications, the group chose pump vibration and system pressures as conditions to monitor. Believing that identifying and solving the problem would likely cost a mint in engineering, monitoring equipment, installation and consulting and maintenance fees, the organization took a different approach.

They used wireless sensors for easy and flexible installation and lower cost than hardwiring. They also deployed a new pump system software simulation program and engaged groups of engineering students from The Pennsylvania State University (Penn State) looking for real-world experience.

Collaborating with sponsors, Penn State technicians and the University Area Joint Authority, student groups addressed pump system efficiency issues using Internet-based sensor technologies and simulation modeling software.

Two student teams sought engineering solutions to one of the biggest challenges in the industrial world: reducing pump inefficiencies that account for up to 20 to 40 percent of wasted electrical energy in industrial and building services. A third team designed and built a pump test loop that was so well done that the sponsoring company intends to continue its use.

Dramatic results

The wireless vibration and pressure sensors captured thousands of systemwide data points that would have been impossible for the maintenance staff to capture through traditional methods. The software simulation allowed the team to test hundreds of pump system adjustments without picking up a wrench. The students, by nature comfortable with big data and new technologies, discovered the root cause and developed a fix.

Although the pump station’s high-head pumps were emitting all kinds of worrisome signals, the pumps weren’t the problem. The real problem was an uphill/downhill, rising/falling pipe system that was siphoning its own flow and causing the pumps to cavitate.

Instead of “deadening” the pumps’ cavitation or increasing the suction pressure (two common suggestions), the students designed a simple circulation system at the highest point of elevation in the piping. This circulation system allows the fluid to catch up with itself before careening down the other side of the hill.

The fix cost $1,000, as opposed to either replacing damaged pumps ($45,000) or responding to a hazardous overflow situation ($100,000 or more).

Wise advice

The next time your pump system shows signs of poor health, look beyond the point where you see or hear a symptom. Ask yourself: What kinds of new wireless technology and software might help identify the cause of this problem? Where can I find a group of eager engineers with the technical savvy to put it all together?

Oh, and next time your foot hurts, check your posture.

About the author

Ben Lawrence (blawrence@kcftech.com) is vice president of KCF Technologies, a technology innovation company based in State College, Pennsylvania, that focuses on putting inventions to work in industrial applications.

About the Hydraulic Institute

The Hydraulic Institute (HI) is the largest association of pump industry manufacturers in North America. Founded in 1917 and based in Parsippany, New Jersey, it serves member companies and pump users by providing product standards and a forum for the exchange of industry information.

The institute has established itself as the leading voice for the North American pump industry. It offers a wide variety of programs and services tailored to member needs: standards development, networking, access to specific statistical data and economic reports, promotional opportunities, educational materials, breaking industry news, participation in industry initiatives and more.

HI’s current programs include a capstone design initiative. An early success of that initiative was a project funded by Flowserve Corporation at Penn State. Working to Flowserve’s specifications, students designed and built a pump loop for future training and testing purposes at the company’s facility in Bethlehem, Pennsylvania.

A team of capstone design students designed a piping layout, purchased construction materials, assembled the loop and then operated it using a pump and motor supplied by Flowserve. The team created a final report documenting all design decisions, appropriate drawings, proper instrumentation and assembly instructions.

“As a fellow engineer, I was impressed how quickly these mechanical engineering students learned to design a solid pump test loop with proper instrumentation using HI standards, with excellent results,” says Jessica Phillips, a Flowserve engineering manager.

The Penn State Capstone Projects are the start of an endeavor by HI and its members to work with manufacturers and engineering universities and colleges to implement diverse capstone programs related to pump systems optimization. Besides expanding awareness of pump system efficiency within the pumping industries, the projects will help to recruit mechanical and industrial engineering graduates to those industries.

“The support of industry for capstone design projects at our nation’s universities is a win-win proposition,” says Gary Koopmann, emeritus professor at Penn State. “Our young
engineers enter the workforce with real-world experience and, in turn, supporting industries are well positioned for early recruiting activities.”

For more about HI, visit www.pumps.org.


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