Archive | Pumps

9

9:00 am
July 12, 2016
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Actuated Diaphragm Metering Pump

1607mtprod17pSeries MP7100 mechanically actuated diaphragm metering pump incorporates the ruggedness of a hydraulic diaphragm metering pump, eliminates the need for intermediate fluid or hydraulic oil to actuate the diaphragm, and reduces the potential for gearbox oil to contaminate the process. The result is a pump design said to provide reliable and accurate dosing of a wide range of mild to aggressive chemicals, including those used in municipal water and wastewater treatment. The pump has a maximum capacity range to 275 gph, pressures to 235 psi, and a suction-lift exceeding 20 ft. on water-like chemicals.

Neptune Chemical Pump Co.
North Wales, PA
neptune1.com

35

5:04 pm
July 5, 2016
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Expanded EnviroGear G Series Trounces Liquid-Transfer Pump Ills

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Grand Terrace, CA-based EnviroGear Pump (part of PSG, a Dover company) PSG Group, has announced the release of  G Series models G1-82, G1-133 and G1-222 (3-in, 4-in., and 6-in.) metal-sealed internal gear pumps.

Well suited, according to the manufacturer, for the most challenging and demanding transfer applications (thin and viscous fluids), the G Series lineup is available in cast iron, carbon steel, and stainless steel models. Delivering flow rates up to 500 gpm, they’re offered with both packing and mechanical seal options, and can be used for a wide range of application types, i.e. chemicals, adhesives, paints, coatings, food & beverage, and heat transfer, among others,

Features and Capabilities
G Series pumps provide positive, non-pulsating flow, and can operate equally in both directions. Features include enlarged bearing housings at the backside of the units that allow for convenient drive-end access to the shaft seal and single-point end-clearance adjustment.

EnviroGear notes that members of its G Series family are interchangeable with up to 95% of existing internal gear pumps on the market, with no modifications to piping, driver, coupling, or baseplate required. The pump casing can be easily rotated for multiple liquid porting positions, making for simple installation in existing applications.

For more information, CLICK HERE.

 

 

99

10:08 pm
June 13, 2016
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Optimize Pump Performance

Group of powerful pumps in modern boiler-house

If pump systems are not optimized, entire processes suffer.

While pumps may be the foot soldiers of the process industries, their quiet dedication means they’re often ignored. That’s a risky business strategy for any site: Components break down, pumps run below optimal efficiency levels, and entire processes suffer. Experts at SKF (Gothenburg, Sweden, and Lansdale, PA) highlight several proven strategies to help optimize your plant’s pump-fleet performance.

Select the right bearing.
Bearings in centrifugal pumps support hydraulic loads imposed on the impeller, the mass of the impeller and shaft, and loads due to couplings and drive systems. They also keep the shaft axial and radial deflections within acceptable limits for the impeller and shaft seal. The bearings often will face high axial loads, marginal lubrication, and high operating temperatures and vibration, all while attempting to minimize friction. If uncontrolled, friction can result in power loss, excessive heat generation, increased noise or wear, and early bearing failure. To optimize a pump’s performance, be sure to evaluate the unit’s bearings (types, designs, and arrangements) in the context of their anticipated operating environment. Suitable bearings are available to satisfy even the most difficult centrifugal-pump applications.

Ensure proper lubrication.
Improper lubrication accounts for more than 30% of bearing failures. Good lubricants prevent metal-to-metal contact and undesired friction. The common methods for the effective lubrication of pump bearings include grease, oil bath, oil ring, and oil mist and air-oil. Oil mist generates the least amount of friction (allowing rotational speed to be based on the bearing design instead of lubrication limitations) and creates a positive pressure within the bearing housing (fending off invasive contaminants). Regardless of lubrication method, always specify lubricants according to the demands on vertical shafts and resistance to solids, pressure, temperatures, loads, and chemical attack.

Seal the system.
Bearing seals in centrifugal pumps retain lubricants or liquids, exclude contaminants, separate fluids, and confine pressure. The choice of a seal for centrifugal-pump bearings depends on the unique demands and operating conditions of the application. Keep in mind, though, that the bearing and sealing arrangement represents an integrated system. Dynamic radial seals generally are the best choice for centrifugal pumps. These designs create a barrier between surfaces in relative motion. Seal selection ultimately must be based on a thorough review of application parameters and environmental factors. For example, seals in pumping applications are often exposed to relatively constant pressure differentials. That makes pressure seals, with their pressurized seal cavities, the preferred choice.

Keep in mind that seals usually have a much shorter service life than the components they protect. Don’t fall into the common habit of scheduling seal replacement only at intervals dictated by other components, such as bearings.

Monitor equipment health.
Regular measurement and analysis of key physical parameters, such as vibration and temperature, can detect pump-system problems before they occur. Basic instruments can assess and report on vibration, temperature, and other parameters. More advanced tools include online surveillance systems and software that can deliver real-time data. Many problems will manifest as vibration, which is widely considered the best operating parameter to judge pump-train condition. Vibration can detect problems such as imbalance, misalignment, bearing oil-film instabilities, rolling bearing degradation, mechanical looseness, structural resonance, and a soft foundation.

Don’t overlook the pivotal role operators can play in pump reliability. They can serve as “eyes and ears” in the detection of equipment faults before problems escalate and also perform basic maintenance tasks. MT

SKF is a global supplier of bearings, seals, mechatronics, lubrication systems, and services that include technical support, maintenance-and-reliability services, engineering consulting, and training. For more information on motor bearings and other technologies and topics, visit skf.com.

34

9:15 pm
June 13, 2016
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Making The Pump (Up)Grade

John Bollebakker is the manager of maintenance and facilities at Chromalloy’s gas-turbine-engine service operation in Tilgren, The Netherlands.

John Bollebakker is the manager of maintenance and facilities at Chromalloy’s gas-turbine-engine service operation in Tilgren, The Netherlands.

Optimizing existing AODD pumps with energy-efficient, air-distribution technology has helped Chromalloy improve its gas-turbine-engine service operations.

Founded in 1951, the technology company Chromalloy (chromalloy.com) is a leading provider of solutions that reduce manufacturing and operating costs and extend the life of gas-turbine engines for customers in the commercial-aviation, military, and power industries. One of Chromalloy’s major facilities, its 120,000-sq.-ft. site in Tilburg, The Netherlands, has been in operation since 1975. The components serviced there reflect a veritable who’s who of turbine-engine manufacturers.

“The Tilburg facility is a repair shop for parts used on airplane engines and in other applications,” explained John Bollebakker, the site’s manager of maintenance and facilities. “If an engine needs an overhaul, certain parts will be sent here, whereupon they will be inspected and repaired, and all necessary paperwork completed. We then deliver the part(s) back to the OEM in the shortest time possible.”

By upgrading its eight existing Wilden AODD pumps with the manufacturer’s Pro- Flo SHIFT air-distribution system (ADS), Chromalloy has been able to significantly reduce its operational costs.

By upgrading its eight existing Wilden AODD pumps with the manufacturer’s Pro- Flo SHIFT air-distribution system (ADS), Chromalloy has been able to significantly reduce its operational costs.

The need to improve

A key stage in the engine-repair process involves the continuous transfer of cooling fluids that help keep repair and refinishing machinery operating safely. Since 1998, Chromalloy has been relying on several Wilden Original Series (clamped) air-operated double-diaphragm (AODD) pumps to reliably facilitate the process.

As Bollebakker describes the process, a press pipe in one area introduces the cooling fluid into the process and from there it runs back to the tank where the Wilden pump pulls it out and sends it to the next installation. “In another area,” he said, “we are pumping with the main pumps to the machines and the Wilden gets the fluid to the tank and back to the filter where it is cooled. After that, the main pumps remove the fluid and pump it back to the machine again.” The Wilden units are used for cooling and filtering.

Bollebakker noted that the Wilden pumps had performed admirably during the 16 years since their installation. The only maintenance seemed to have been associated with seal replacements, “once a year or so.” Still, evolving operational demands regarding air usage, efficiency, noise levels, and overall operating costs had led him to consider ways that pump performance could be improved.

Although the Tilburg site was seeking more efficiency from its pumps, it also needed to consider safety issues. “We want a healthy work environment,” Bollebakker stated. “Therefore, we were looking at where we could improve environmental issues or create cost savings by doing whatever it takes to make our ROI the right percentage. From all aspects, we try to do the best thing we can for the company. It should fit into the complete organization, but also fit into the budget.”

In 2013, to help identify pumping technologies that could improve efficiency and cost effectiveness while making operations more “green,” Bollebakker contacted Chromalloy’s pump supplier, Holland Air Pumps, Oirschot, The Netherlands—specifically its commercial director Gerrit Klaassen.

Too good to be true?

Klaassen pointed out that Bollebakker’s search for a more efficient AODD pump came at an ideal time. In June 2013, Wilden introduced its Pro-Flo SHIFT air-distribution system (ADS), featuring an air-control spool that eliminates costly air “overfilling” at the completion of the pump stroke. According to the manufacturer, Pro-Flo SHIFT-equipped pumps lead to savings in air consumption of as much as 60%, while costing 50% less to operate than AODD units with traditional mechanical or electronically actuated ADS technologies.

Reports of that level of performance might have sounded “too good to be true” in some quarters. Committed to proving otherwise, Holland Air Pumps built a skid-based Pro-Flo SHIFT-equipped pump unit and transported it to actual customer sites where the technology was put to the test. Klaassen and others on the distributor’s team, including owner Leo de Haas, have fond memories of the traveling “road show” and its ability to clearly demonstrate how the new ADS worked and what it could do for customer operations. “When they saw it [in operation] for themselves and listened to the pump [as it ran],” he said, “they realized that they suddenly had 30% to 40% more capacity.”

Chromalloy’s Bollebakker was one of those customers. Klaassen conducted a test for him and a colleague at the Tilgren facility in Dec. 2013. Both were intrigued by what they saw. Later, when Wilden provided an overview projection of what the site could save by upgrading existing AODD units with the Pro-Flo SHIFT ADS, Bollebakker was convinced. At that point, he went on to convince the facility’s general manager, and the purchase was quickly approved.

The upgrade itself went smoothly. According to Bollebakker, removing the old ADSs from the site’s existing Wilden pumps and inserting the new Pro-Flo SHIFT ADSs was a simple task. In fact, there was negligible impact on the facility’s 16-hr. daily operating schedule.

“From a production point of view,” Bollebakker said, “I can’t allow myself to go without production for four or six or eight hours, because we have to run for 16. In reality, each of the eight pumps was out of production for only one or two hours. It was an easy job.”

Once the pumps with the new Pro-Flo SHIFT ADS were up and running, it wasn’t long before Bollebakker began to notice—and document—the cost savings. “We’ve taken four cents per cubic meter per hour (m3/hr.) off the operating cost, and at 16 hours per day, five days a week, we calculated that we will be saving €11,000 (US$12,020) per year for the eight pumps,” he marveled. (Translation: The Pro-Flo SHIFT ADS investment would pay for itself in 12 months.)

Seeing is believing

“The Tilgren plant has several areas where we try to improve our systems and look constantly for ways to do things quicker, better, faster,” said Bollebakker. “From the moment we rebuilt the air section on the Wilden pumps, there was an immediate reduction in air supply, but the flow remained the same. When the pump comes in and it’s working the way we want it to work, the case is closed.” MT

Wilden invented AODD technology in 1955. The business is now a brand of Oakbrook Terrace, IL-based PSG, a Dover company. For more information, visit wildenpump.com and psgdover.com.

40

4:41 pm
June 3, 2016
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White Paper | Pump Monitoring and What’s New with API Standard 682

160603ep_transmitterThis white paper from Emerson Process Management, released in July 2015, delves into the ramifications of the API 682 standard for pump sealing systems in the oil and gas and chemical industries. The standard provides new roadmaps for operations and maintenance (O&P) teams on how to move towards continuous monitoring of pump systems.

This paper examines asset management strategies, along with IIoT foundation solutions, as seen below from this except:

According to API Standard 682 Fourth Edition, offshore platforms, onshore wellheads, refineries, and petrochemical plants need to evaluate what pump monitoring measurements are in place, which measurements require manual field checks, and which should be automated or upgraded to a better option.

Due to the costs associated with monitoring the process using wired instruments, only a small percentage of a typical process facility’s pumps are monitored online. The balance of pumps are inspected only periodically by operations or maintenance personnel on field rounds.

Read the white paper >>

 

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>> Find more Industrial Internet of Things coverage at maintenancetechnology.com/iot

54

4:07 pm
April 12, 2016
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Injection Pumps Provide Reliability For Gas Producer

The BB3 API-standard bare-shaft pump offers “drop-in” installation that fits in existing infrastructure. Photos: Standard Alloys

The BB3 API-standard bare-shaft pump offers “drop-in” installation that fits in existing infrastructure. Photos: Standard Alloys

Horizontal split-case pumps transfer gas from storage wells to the pipeline.

By Bryan Orchard

The BB3 horizontally split-case API pump is used extensively by pipeline companies operating in the shale gas, liquefied-petroleum gas (LPG) and liquefied-natural gas (LNG) markets.

“BB3 pumps are used within terminals to transfer the gas into the pipelines from storage wells,” explained Richard Martinez, managing director at Standard Alloys Inc., Port Arthur, TX. “These pipelines employ pump stations at various intervals along their length, and many of these pumps are coming to the end of their service lives. There is no desire to replace redundant pumps with new units. The last thing that they want to do is change drivers, put in new foundations, and change piping connections to accommodate new designs.”

The most cost-efficient solution is to use a bare-shaft pump that can be easily dropped into the existing infrastructure where operators know that the nozzles, casing feet, and shaft couplings will fit.

A SUCCESSFUL APPLICATION

Targa Resources Corp., Houston, is a provider of midstream services in North America. In 2015, Targa installed a BB3 pump for the specific duty of injecting ethane propane mix (EP) into storage wells at the plant’s salt dome. The double volute, eight-stage split-case centrifugal pump is fitted with 10.187-in. closed impellers and provides a flow of 1,200 gpm running at 4,000 rpm, with a suction pressure of 260 psig, and a total developed head of 3,800 ft. The pump can graduate from moving a product of specific gravity 0.38 all the way up to 0.50, which gives them the ability to move heavier end products. Installed on an existing product train, the pump has been built specifically for this application.

“We were given the flow parameters and head capacities. We went into our database to see what we had that was closest to the specification,” Martinez said. “We found a closely-matched pump and used this as a platform to custom build the flow and head required. We produced a special package that went beyond the generic specification typically found in API-610. It had to fit the same foundation as the original pump, so a custom base was designed to facilitate a perfect fit.”

Martinez said his company had already supplied similar pumps for transfer duties, but this one was specifically engineered for well injection.

The rotating element is set inside the lower casing during manufacturing.

The rotating element is set inside the lower casing during manufacturing.

HIGH RELIABILITY

Steve Ferguson, Targa’s rotating-maintenance supervisor emphasized the importance of extreme reliability for this application. Regular maintenance inspections are implemented by Ferguson’s reliability team. The new injection pump has replaced a standby pump that had reached the end of its service life. For reasons associated with the casing, it had to be condemned.            “A problem with older pumps is that in the event of failure, weld repair from erosion will be required,” Ferguson said. “This is not possible because, over time, electrolysis leaches the carbon out of the material so the base metal will not accept the weld metal. Also, there is the problem of carbons leaching, which weakens the case. Pressure testing repairs cannot be performed. Therefore, replacement pumps are required.”

For years Standard Alloys’ core business was in manufacturing replacement pump parts. In 1992 this changed when the company made its first complete bare-shaft pump. Now they produce API qualified bare-shaft replacement pumps for brownfield and greenfield applications, exploiting opportunities where an existing pump may be obsolete or where material or engineering upgrades are needed.

“Our target is pump operators that may have seventh or eighth edition API pumps that need replacing with a direct ‘drop-in’ ,” Martinez said. “They don’t want to change the foundation due to the casing foot location or modify the suction and discharge nozzles. They also don’t want to relocate the drive unit. RP

Bryan Orchard is an independent journalist reporting for KSB Group.

58

8:17 pm
April 11, 2016
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My Take: Get Pumped

1014janemytakeBy Jane Alexander, Managing Editor

As mentioned in this column before, editing magazines is my second career. It started almost 17 years ago when I began covering all things related to the industrial-fluid-handling pump market.

Oh, what a big “room” that was! Thrown into it by accident, I soon learned that pumps, after electric motors, were the most purchased industrial items in the world. Pumping systems, i.e., pumps, seals, bearings, motors, controls, instrumentation, and the technologies that kept everything aligned and running as desired, became a major focus for me. As did pump-user workforce issues—something that was also capturing the serious attention of pump-using industries.

For me, the ongoing skilled workforce crisis that Maintenance Technology has been highlighting for the past decade first reared its ugly head in the pump world. Circa 1999, operations were already anguishing over the loss of seasoned pump pros from their ranks. The amount of “tribal knowledge” disappearing with the “old hands” was alarming, given the fact pump operation and maintenance courses typically weren’t a big part of engineering- or vocational-school curricula.

Granted, Dr. Dara Childs and the Texas A&M Univ. (TAMU) Turbomachinery Laboratory, College Station, were trying to keep practical pump education and knowledge transfer alive. The Advisory Board of the TAMU Pump Symposium (now in its 32nd year) was a veritable “Who’s Who” of the greatest living pump experts on the planet. Still, the timing and location of the annual Houston-based Symposium weren’t necessarily the best for all aspiring pump users across North America, and programs sometimes skewed toward the theoretical.

While pump-industry suppliers had always offered various training courses to meet growing demand, other opportunities—often hands-on in nature—began appearing around the country. One example that immediately comes to mind is the long-running Mid-Atlantic Pump Symposium, presented by the Baltimore/Philadelphia-based industrial-equipment distributor Geiger-Smith Koch.

There were other efforts as well, including a number of value-added, non-Houston-based, open training sessions and workshops. That’s how I met one of my favorite pump-training gurus, Sam Buckles, of Eli Lilly and Co., Indianapolis. He and his enormous working-pump rig appeared on my radar screen in one of the first such workshops I attended—and I continued to see him using the equipment to train new generations of pump users throughout industry (much like he did at Eli Lilly) several times thereafter.

Although Sam has retired, I understand his well-traveled pump-training equipment is still in service. I was delighted to learn of this at the 2016 Univ. of Tennessee Maintenance & Reliability Conference (MARCON) in Knoxville. That’s where I met an amazing woman named Rendela Wenzel.

As an Indianapolis-based consultant engineer in Eli Lilly’s Global Plant Engineering, Maintenance, and Reliability organization, Rendela has done—and continues to do—many interesting things. Among them, she implemented pump training courses for the masses at Eli Lilly, and now drives the company’s global pump, vacuum-pump, mechanical-seal, and basic and advanced lubrication-fundamentals training programs. Accordingly, she has become the keeper of Sam Buckles’ training rig. Having gotten to know her, I’m confident this equipment and the associated training programs, like everything else that she manages for Eli Lilly, are in good hands. To learn why, turn to page 17. 

Rendela Wenzel is the subject of this month’s “Voice from the Field” profile by contributing editor, Michelle Segrest (another veteran of the pump arena, BTW). My take is that you’ll be just as impressed with this industry “Voice” as we are.

On a related note, speaking of pumping systems and amazing women, check out April’s special “Reliable Pumping Section” that Michelle Segrest also produced. Beginning here and focusing on oil and gas matters, it’s the first in a series of sections on various pumping applications that we’ll run this year. Stay tuned. MT

jalexander@maintenancetechnology.com

470

1:51 am
April 11, 2016
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Solve Oil and Gas Pumping Maintenance Problems

Blackmer sliding-vane pumps stand ready to meet the needs of the rapidly growing oil and gas industry in the United States. Photo courtesy of Blackmer, a brand of Dover’s Pump Solutions Group.

Blackmer sliding-vane pumps stand ready to meet the needs of the rapidly growing oil and gas industry in the United States. Photo courtesy of Blackmer, a brand of PSG, a Dover company.

Experts describe some of the common maintenance issues that arise in oil and gas pumping systems, and demonstrate some of the ways to solve them.

By Michelle Segrest, Contributing Editor

In some parts of North America, you can still clearly see the oil and gas pumping industry hard at work. Fly over Texas and see a checkerboard of sucker-rod “donkey” pumps, nodding in unison, pulling up millions of barrels of oil from deep beneath the surface.

At hydraulic fracturing sites, gigantic “frac” pumps dominate the landscape and shake the earth—splitting the mud, shale, and rock into bits with enormous pressure. That’s how oil corporations and service companies capture the elusive black gold buried deep inside—the material that literally fuels the multi-billion dollar oil and gas industry.

You can’t see the pumps that dive thousands of feet below the ocean’s surface from offshore rigs, and the pumps that transport the oil and gas are not visible, either. Hidden inside about 140 huge refineries throughout the U.S. there are even more pumps that keep the oil and gas industry functioning. It is up to the experienced maintenance professionals to make sure all of these pumps are hard at work every second of every day.

The massive oil and gas industry relies on a wide variety of pumps to perform every stage of the process—including upstream, midstream, and downstream functions. According to The Freedonia Group, Cleveland, the United States demand for oil and gas infrastructure equipment is forecast to hit $12.1 billion through 2016, which makes this a market that is vitally dependent on equipment that runs efficiently.

Quickly identifying problems and solving them effectively is vital to this giant industry.

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(Click to enlarge.)

Common problems and solutions

Different pumps present different obstacles, especially within a market as diverse as oil and gas. Mark Dufrene is the general manager for Pump & Process Technologies, a division of CastleOak LLC in Longview, TX—a distributor of Blackmer, Pentair, EnviroGear, Aurora, Fairbanks, Myers, and other centrifugal, rotary-gear, positive-displacement, and reciprocating pump brands for oil and gas applications. Each pump for each application must be treated differently.

According to Dufrene, a 27-year veteran of the pump industry, “There is a tendency to treat centrifugal and positive-displacement pumps the same. Some people use a control system on centrifugal pumps and just throttle back on the valve to control the flow. You can’t do this with a positive-displacement pump because, when you throttle back on the discharge valve, you create more pressure. It becomes self-defeating.”

One of the biggest problems contributing to excessive pump maintenance in the oil and gas space involves having a pump that is improperly sized or misaligned, Dufrene said. “People sometimes think bigger is better, but this is not always the case,” he said. “This can be a system issue.”

Advancements in technology, such as variable-frequency drives (VFDs), have contributed greatly to the longevity of most oil and gas pumps and have helped keep the maintenance manageable. A VFD is a type of adjustable-speed drive used in electro-mechanical drive systems to control AC motor speed and torque by varying motor input frequency and voltage.

VFDs can optimize impeller diameter, which slows down the equipment and gives it longer life and less wear. “Instead of running the equipment at 1,800 rpm, with a maximum impeller diameter it can run at 1,400 rpm,” Dufrene explained. “This doesn’t sound like much, but it makes a big difference. It can extend the life of the pump and prevent it from running dry and cavitating. VFDs and other PLC controls can help to eliminate some of the misapplied and improperly sized equipment because you can use the speed control to compensate for errors made in pump selection.”

Changes are inevitable, and each change presents new maintenance concerns. “Every day is different,” Dufrene said. “If a guy has a mission to pump liquid from Point A to Point B, that is pretty simple—but it is not reality. When you dive into someone’s process and discover they want to pump from Point A to Point B to Point S to Point Z, it becomes more complicated. Every time they make a change, the system curve changes. Therefore, the pump curves change, but they may be using a fixed-speed piece of equipment to do all of the applications. This is not realistic, and it leads to problems. The pump does not always operate at the one design point. This is a dynamic system as opposed to a static system.”

A Griswold 811 series pump installed in a Lease Asset Custody Transfer (LACT) unit located in the Eagle Ford play in Texas. A LACT unit automatically measures, samples, and transfers the oil from a lease location in the oilfield into a pipeline. Photo courtesy of Griswold, a brand of PSG, a Dover company.

A Griswold 811 series pump installed in a Lease Asset Custody Transfer (LACT) unit located in the Eagle Ford play in Texas. A LACT unit automatically measures, samples, and transfers the oil from a lease location in the oilfield into a pipeline. Photo courtesy of Griswold, a brand of PSG, a Dover company.

Five pump-maintenance problems

Odessa Pumps, a DistributionNOW Company, has been providing equipment to the oil and gas market for more than 30 years with a full range of applications, including chemical injection and high-pressure injection pumps. Joe Lewallen, Jr. is the general manager of Applied Pumping Solutions for Odessa Pumps’ Irving, TX operation, and Brian Verdehem is director of sales. They describe their five most common maintenance problems and solutions for oil and gas pumping applications.

Improperly sized and installed equipment. “It’s a fact that the majority of centrifugal pumps installed today are oversized.” Verdehem said.  Pumps are often oversized for an application then operated in an unstable region of the centrifugal pump performance curve. “Operating in these unstable regions of the pump curve can result in lower mean time between repair (MTBR) on the seal and bearings, as well as the turned and cast components,” Verdehem said. “This is especially prevalent in pumps with higher suction specific speeds (>11,000 Nss), where the stability window on the curve is less forgiving. These factors can often be avoided by properly sizing the pump and configuring the pump package with a VFD. Operating in variable speed can ‘right size’ the pump performance curve to the current system variables. Having a pump supplier who knows pump hydraulics and who can evaluate the system head variables is essential to implanting a successful VFD system into a pump installation.”   

Screen Shot 2016-04-12 at 10.37.06 AMImproper installation and baseplate design. According to Lewallen, “After the pump is chosen for an application the next step is to provide the best possible base for the pumping unit. This involves engineering the pump skids and the use of advanced baseplate design for the pump units. Odessa Pumps provides Griswold ANSI pumps on our DurAlign baseplate to ensure the best possible motor-to-pump shaft alignment.” Machined pump and motor pads ensure that the manufacturer’s installation requirements can be met and maintained. “For the Blackmer rotary-vane packages, our engineers design and oversee the manufacturing of heavy duty baseplates with the same machined pads to ensure long trouble-free operation,” he said.

Contamination of lubrication leads to bearing failure. Bearing failure is the biggest cause of maintenance issues in pumping applications. Proper lubrication of the bearing is the simplest way to avoid it. “Changing and maintaining an optimal environment for the lubrication fluid by investing in labyrinth or magnetic type bearing isolators, can provide great benefits on extending the machine life on oil-sump designs, and avoiding unexpected failures. Investments in oil-mist systems are often an efficient way of lubricating multiple pump assets within a consolidated production or process unit,” Verdehem said.   

Improper mechanical-seal selection results in premature seal failure. Centrifugal pump units in the oil and gas sector also require an extensive knowledge of mechanical seals. “New sealing technology and proper material selection leads to longer operation before service is required,” Lewallen said. “Many customers and equipment providers omit this important part of pump application. Misapplication of the seal design is one of the most common areas of centrifugal pump failure, and once the seal fails, that can lead to loss of product, environmental contamination, and other maintenance issues.”

Incorrect material selection on pump material and gasket/elastomers, resulting in premature failure. “Liquid compatibility with the gaskets and elastomers in a pump’s construction are often overlooked by customers and inexperienced pump suppliers,” Verdehem said. Taking the extra time to ensure that your metallic and non-metallic pump components are compatible with the liquid during the pump-proposal stage, can help decrease the onset of premature and costly downtime. There are plenty of publications and compatibility charts available online for use in confirming compatibility on metallic and polymer based components. An experienced pump supplier will take a conservative approach on material selection if they have full transparency on the customer’s liquid properties and process conditions. It’s important that customers provide the pump supplier with this information at time of quote request.

Best maintenance practices

Preventive maintenance in oil and gas pumping applications is much the same as in other industries, Lewallen said. “On larger horsepower equipment a baseline vibration reading is taken when the equipment is commissioned. Our technicians provide a PM service for many of our customers. With an initial vibration reading by our technicians, subsequent readings can identify a problem early.” 

“Shaft alignment to the manufacturer’s specification is also crucial,” Lewallen said. “The proper use of shaft sealing technology is another important factor for equipment reliability. Preventive maintenance performed by properly trained personnel will ensure long run times and prevent premature failure.”

Another best practice, according to Verdehem, is a proactive maintenance culture. “It’s no different than changing the oil in your car as instructed by the owner’s manual,” he said. “Most centrifugal-pump failures are a result of bearing and seal failure, so it is important that these two areas are given the most concentration.”

Monitoring vibration on a regular basis and identifying changes in the vibration spectrum can warn of a pending failure. “This way you can plan the maintenance and shutdown of the equipment. Proactive machine-health monitoring can have tremendous benefits for most types of rotating equipment,” Verdehem said.

Horse-head pump jacks at a Canadian site. Photo courtesy of ExxonMobil.

Horse-head pump jacks at a Canadian site. Photo courtesy of ExxonMobil.

Maintenance Challenges

Oil and gas pump professionals face challenging maintenance obstacles daily. Here are four interesting case studies:

VFDs at a Blending Facility. VFDs were used to optimize positive-displacement pumps for two different functions at a blending facility—loading trucks and loading totes and drums. “We use the VFD systems and run them at different settings,” CastleOak’s Mark Dufrene said. “To load the truck involves pumping 150 gpm. To load drums and totes the pump should run at about half speed. The VFD switches on, slowly fills up the drum to a certain level, then it ramps down and shuts off the unit. Instead of having someone over there with a trigger, it’s all automated. To improve the life of the pump, over time we are regulating the speed to slow the unit down and match application conditions. This increases reliability and MTBF.”

Refinery Condition-Monitoring System. Dufrene said his refinery customer had a boiler system that would run effectively most of the time. But, in certain circumstances, the pump would cavitate and fail. “No one could pinpoint the problem,” he said. “You could stand there for two or three days and nothing would happen. But as soon as you went home, the upset condition would occur. So we added a monitoring system to measure the suction pressure, discharge pressure, and temperature.”

Dufrene’s team placed a probe on the bearing frame to measure the product temperature and discovered that when certain systems in the plant were running, the pump was oversized for the application. The plant was running at maximum capacity most of the time.

“When it went to half capacity, they started having problems,” he said. “Using the monitoring equipment, we were able to chart exactly when it occurred and found out how the plant was operating. This showed us where to look to solve the problem. This is an example of when you take a little time and a little thought process you can make a big difference beyond just fixing it.”

VFDs for Centrifugal Pumping Systems. In most pumping applications, trimming the impeller reduces pump efficiency, sometimes by as much as 20% to 25%, Dufrene said. Running the system at the optimum impeller diameter and controlling the speed dramatically increases efficiency. “As conditions like head and pressure change, the VFD can speed up and match the system, as opposed to running to the right or to the left, which actually causes more maintenance problems,” he said. “If you use a VFD, you can match the system you have and improve efficiency.”

Centrifugal Pump Running Dry. A centrifugal pump running dry can be a challenge in many applications, and especially in the oil and gas industry. This is particularly an issue in tank or rail car unloading applications, as well as
certain applications within the pipeline, Verdehem said. 

“Dry run is the Achilles heel for pumps that have metal-to-metal wear ring designs on the rotary and stationary ring configuration,” Verdehem said. “Failures in this mode can often cost as much or more than a new pump unit. In these applications, customers can move to a stationary wear-ring insert constructed of a fiber-reinforced fluoropolymer material, with low creep and high thermal resistance. These materials on the stationary ring will not allow excessive heat build up during dry-run anomalies. This saves the pump from catastrophic damage due to dry run.”

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Tools of the trade

A big concern in the oil and gas rotating-equipment industry is the knowledge and experience gap with new professionals entering the industry and the retiring workforce. “Tools and gadgets and automation can give us quicker and more accurate responses,” Dufrene said. “But we still need to have a deep understanding of the fundamentals of the problems.”

Verdehem said that investing in a quality and reliable alignment device can provide long-term benefits for installed equipment. “Without proper alignment, one is installing a bad actor at the time of installation,” he said. “A vibration analyzer capable of generating a full spectrum can be a worthy investment from a predictive-maintenance perspective.”

Remote monitoring has been one of the biggest developments in the past decade, Dufrene said. “A lot of this equipment is installed in remote sites, and you can’t go out there and monitor it regularly,” he said. “A monitoring system sends an alarm or shuts down the equipment. This is a big advantage instead of having to ride out to 100 fields every day to check the equipment.”

Also, partnering with pump suppliers who have the experience with proper pump selection, installation, operation, and maintenance can provide long-term benefits to the end user, the experts agree. “Many pump suppliers have implemented a business model of only selling the new equipment and parts at a low price,” Verdehem said. “Those who can do that, plus provide the field and consultative services after the sale, are the partners that reliability-savvy customers value the most.” RP

Michelle Segrest has been a professional journalist for 27 years and has covered the industrial processing industries around the globe. Reach her at michelle@navigatecontent.com.

Maintaining Hydraulic Fracturing Pumps

ExxonMobil engineers inspect an oil and gas hydraulic fracturing truck. Photo courtesy of ExxonMobil.

ExxonMobil engineers inspect an oil and gas hydraulic fracturing truck. Photo courtesy of ExxonMobil.

Hydraulic fracturing pumps used in oil and gas service work are highly engineered, expensive pieces of equipment that can generate pressures as high as 20,000 psi and can weigh as much as 9 tons. Today’s multi-stage frac jobs mean longer pumping times, according to Kevin Hunter, Equipment Builder Group Engineer, Global Products Technology, ExxonMobil. 

Shale reservoirs are the driver of much of the fracking work today and often require extremely high pressures, Hunter said. These factors have combined to force hydraulic fracturing pumps to work harder than ever.

“These critical pumps have to pump abrasive fluid in multiple stages on each job and there may be 15 or more frac trucks and pumps on a single frac job,” Hunter said. “Frac pumps have to operate almost continually for several days before moving to the next job. Uptime is critical as the locations are often several hours driving time from their support site, and they may have a series of consecutive jobs scheduled.”

Pump builders are constantly working to update designs to improve reliability. Optimum lubrication can also improve uptime and extend maintenance intervals.

Frac pumps are comprised of two key components—the power end and the fluid end. The power end includes a gear set that takes the power from an engine and transmits it to the crankshaft in the power end used to drive the plungers that push the frac fluid.

One oil in the power end not only has to lubricate the gear set—which may be a helical, planetary, or a worm gear—but it must also lubricate the roller bearings, main bearings, connecting rod bearings, and crosshead guides.

“This requires a lubricant that can protect these diverse components in severe service, and in all weather conditions as the seasons change,” Hunter said.  “In addition, the frac unit may be moved from one geographic area to another to meet demand as ambient conditions change. A lubricant that can deal with a wide range of temperatures is important. In addition, the oil needs to flow well during cold starts in winter weather, flowing to all parts of the power end while still providing protection during a long frac job, despite the elevated temperature, which reduces oil viscosity.”

Typically, the biggest failure mode in power ends is the bearings. 

The other key component of a frac pump is the fluid end where the plungers apply pressure to the frac fluid. One key maintenance issue for fluid ends is maximizing plunger-packing life. In addition to good design and manufacturing processes, lubrication contributes to maximum plunger packing life. 

Traditionally, rock drill oils delivered by a centralized lubrication system have been used in most pump designs. With ever-increasing environmental concern and reducing spills, many operators are migrating to grease for plunger lubrication.

“This requires a grease that can readily be pumped via the centralized lubrication system, which has relatively long lines leading to the fluid end of the frac pump,” Hunter said. “This requires a grease that pumps well while still providing good lubrication at the packing.”

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