Archive | Pumps

37

7:25 pm
April 13, 2017
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Surge Vessels Address Hydraulic Shock

Properly implemented surge vessels can optimize pump/piping-system performance and address hydraulic shock.

By Frank Knowles Smith III and Steve Mungari, Blacoh Fluid Controls Inc.

Damage to pumps and piping systems from hydraulic shock, also known as water hammer, can often result in catastrophic failure, along with expensive repair and downtime. 

In the world of petrochemical processes, hazardous conditions resulting from pump damage or line breaks can also bring about significant liability concerns, along with very negative publicity. With many plants and facilities currently in operation without protection against hydraulic shock, what can be done from a maintenance, repair, and operations (MRO) standpoint to avoid this inevitable problem? 

The issue

Under steady-state conditions, a plant’s pumping system will tend to operate near the nominal working pressure unless there is change of flow velocity. This change is defined as hydraulic shock and immediate mitigation efforts are needed to prevent damage from occurring. 

This fluid acceleration or deceleration can be attributed to several likely causes, with the most common being from either “pump trip,” or sudden valve closure. A pump trip, generated by sudden loss of power to the pump station or by a pump stop without warning, can drop the working pressures near the pump’s discharge side to negative levels and cause possible vapor-pocket collapse.

The sudden valve closure from electrical, hydraulic,  or mechanical failure, or from human action, can result in a dramatic increase in pressure at the inlet side of the closed valve. That pressure increase is experienced as high-velocity (potentially exceeding 4,000 ft./sec.) transient pressure waves that will oscillate throughout the piping network unless the transient wave energy can be suppressed. 

Pipes that shake violently, even occasionally with restrained piping, and with loud banging noises are the ones typically experiencing hydraulic shock. Pumps and motors are also likely to be damaged concurrently as the transient-pressure energy waves travel back through the pump until the check valve slams shut.    

Weak points in the piping network, such as flange connections and pipe elbows, tend to bear the brunt of the pressure wave’s damaging effect and are often the first to break.    

In a single-pump system, several transient-mitigation options are available to address the transient wave’s effects. Some of the most popular are surge vessels, air-release/vacuum valves, pressure-relief valves, surge-anticipator valves, and vacuum breakers. Even with an existing facility or pipeline, space is often readily available to accommodate which specific pieces of mitigation equipment are necessary to solve the problem. However, what does the facility do when the plant is pumping in series?

Case in point

A large oil-industry customer, involved with a chemical-process application, was looking for a way to protect their pumping system infrastructure from damage and repair expenses, along with reducing lost product costs from the breaks. 

For their application, a booster pump (which requires a minimum of 100 psi NPSH (net-positive suction head) is located approximately 10,000 ft. from a high-pressure injection pump. When power is lost at the booster pump’s location, with the high-pressure pump operating, a transient negative-pressure wave is generated. 

This wave causes a sudden pressure drop at the booster pump’s discharge side and travels at approximately 4,000 ft./sec., making contact with the high-pressure pump. In this situation, it’s important to protect the high-pressure pump from cavitation damage and maintain a minimum 100 psi NPSH on the booster pump.

Monitoring and protecting

Should the high-pressure pump trip when the booster pump is running, a high-pressure “up surge” transient pressure wave will be created at the inlet flange of the high-pressure pump. High pressure can also bypass the check valve and cause additional damage.

A properly sized surge vessel, with the sizing calculated through the use of computer surge-analysis software at the high-pressure pump, will accept energy from the pump trip. It will also be able to accept energy (compress vessel gas volume) on a high-pressure pump trip. 

On the high-pressure pump trip, the flow will stop, based on the system demand, and will pump dynamic head. However, there is a concern of reversal of flow back through the high-pressure pump from the up-surge transient wave due to check-valve closing time. 

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Fig. 1: Negative-pressure transient wave. Graph shows a transient negative-pressure wave on a pump’s discharge side that occurs when power is lost to a booster pump. Green shows booster-pump pressure and red shows high-pressure-pump pressure.

A properly sized surge vessel will accept the transient energy, but check-valve closing time will vary,  based on factors such as type of valve and pipe size. With the specific closing time a critical factor to the accuracy of the results from the computer surge analysis, this must be properly entered into the analysis. The results of the analysis can be verified at the time of commissioning using a report from a transient pressure-monitoring system, with the data being read and recorded at a minimum of 100 times/sec.

Fig. 2: Pressure variation without a surge vessel. Fig. 2 shows pressure variation in a system that is not equipped with a surge vessel. Green is the booster-pump pressure and red is high-pressure-pump pressure.

Fig. 2: Pressure variation without a surge vessel. Fig. 2 shows pressure variation in a system that is not equipped with a surge vessel. Green is the booster-pump pressure and red is high-pressure-pump pressure.

When evaluating how to size a surge vessel to deliver energy, or to keep the high-pressure pump’s NPSH correct in time to de-energize, further computer surge analysis is needed. In this example, the graph in Fig. 2 shows the booster pump tripped (pressure shown in green) while the high-pressure-pump suction pressure is shown in red. In monitoring the liquid level and pressure in the high-pressure pump’s suction-stabilizer surge vessel, the high-pressure pump can be successfully de-energized in 15 sec.

Fig. 3: Surge-vessel pressure at booster pump. Figure 3 shows the pressure inside of a surge vessel at the booster pump.

Fig. 3: Surge-vessel pressure at booster pump. Figure 3 shows the pressure inside of a surge vessel at the booster pump.

The pressure drop to the high-pressure pump’s minimum NPSH will keep the pump protected. Figures 3 and 4 show the change in pressure inside the surge vessel placed at the booster pump and at the high-pressure pump.

Fig. 4: Surge-vessel pressure at high-pressure pump. Figure 4 shows the pressure inside of a 106-ft3 surge vessel at a high-pressure pump.

Fig. 4: Surge-vessel pressure at high-pressure pump. Figure 4 shows the pressure inside of a 106-ft3 surge vessel at a high-pressure pump.

By making use of computer surge analysis to correctly assess the conditions with the booster and high-pressure pump conditions, the customer was able to understand how properly sized and placed surge vessels can assure optimize operational performance by confirming proof of design with transient monitoring of pressure and flow.

With the surge vessels properly located, potential damage to the pumps and piping network from hydraulic shock was eliminated. As a result, considerable time and equipment cost savings were realized.RP

Frank Knowles Smith III is executive vice president of the Surge Control team at Blacoh Fluid Controls Inc., Riverside, CA (blacoh.com). He has three decades of academic, design, and application experience. Steve Mungari is the business development manager at Blacoh. He has more than 20 years of process-control experience in the areas of fluid measurement and control technologies.

76

7:11 pm
April 13, 2017
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Pump OEMs Address Oil and Gas Trends

Pump suppliers discuss trends and challenges in the oil and gas industry involving smart technology, competitive delivery, and optimized equipment efficiency.

As the use of vapor-recovery units (VRU) at oilfield storage-tank facilities grows, so does the need to understand that proper skid-assembly installation will help guarantee their reliable performance.

As the use of vapor-recovery units (VRU) at oilfield storage-tank facilities grows, so does the need to understand that proper skid-assembly installation will help guarantee their reliable performance.

By Michelle Segrest, Contributing Editor

Speed, portability, and reliability are key factors in optimizing production times and the bottom line in the oil and gas industry, according to experts from major pumping technology companies.

Glenn Webb, senior product specialist for Blackmer, Grand Rapids, MI, a leading brand from PSG, (Oakbrook Terrace, IL) said that the most obvious positive manifestation of the ongoing oil and natural gas production boom in the United States can be seen on street corners across the nation. At the end of January 2014, the average price at the pump nationwide for a gallon of gasoline was $3.28. One year later, the price for a gallon of gas had plummeted to $2.04.

Increased production in such prominent shale fields as the Bakken in North Dakota, Eagle Ford in Texas, Niobrara in Colorado, and Marcellus and Utica in New York, Ohio, West Virginia and Pennsylvania, has increased the demand for gathering, transport, and terminal systems that can store raw crude oil and natural gas until it can be shipped by truck, train, or pipeline for refinement and consumption With these increased challenges come innovative solutions.

Smart instrumentation

Some companies offer valve and pump products with smart instrumentation to monitor factors such as motor vibration, pump vibration, inlet pressure, outlet or discharge pressure, pipeline temperature, gear-box oil temperature, voltage, amp draw, supply pressure to valve controllers, actuator blow by, and smart-wear monitoring of internal wear components, according to Todd Loudin, president of North American Operations and VP Global Sales for Flowrox Inc., Linthicum, MD.

Loudin said Flowrox has experienced three major challenges for the oil and gas industry:

The price of crude. Many oil producers, especially within shale regions, require a minimum of $30/barrel. But only about 50% of the wells in the Bakken or Permian Basin break even at $30/barrel. The other 50% break even at around $60/barrel. There are some wells that have difficulty breaking even at as high as $100.

Capital investment has been slashed by the industry. Of course, investments will occur that are imperative to continued production, but budgets have been constrained, Loudin said.

A significant reduction in work force. One solution that the oil industry has embraced, according to Loudin, is intelligent instrumentation and monitoring for the production and refining process. “Some of these systems are not ideal and useable to the people doing maintenance or rebuild work,” Loudin stated. “The main variables are typically displayed on a distributed-control system (DCS) with an operator who can provide information on pressure, temperature, flow, and other variables. However, the person in the field does not have easy access to this information. One way we are helping companies in all industries is through our Malibu Smartware. This system creates a 3D visual of the process and process equipment. Key operational information on a given asset can be viewed by an operator or maintenance person on their smart phone, tablet, or PC, wherever they are. They can be standing right in front of the asset and see operating parameters, maintenance videos, drawings, past work history on the asset and even can get confirmation about spare parts in stock for repair.”

This software captures data regardless of where it is stored in the facility or offshore rig and provides it at the device level with only one username and password. To further expand on the use of smart software, it can allow condition monitoring of all kinds of assets, Loudin added. Through predictive analytics, the system learns what a normal condition looks like. When anomalies occur, warnings are sent to maintenance personnel.

These solutions can be cloud based or housed on the owner’s servers or their own secure cloud. The system uses the same encryption as the Internet banking industry.  

Quality manufacturing

Mark Weidmann, vice president sales-Midstream/Downstream O&G at PumpWorks610, a DXPE Company (Houston) said that customers ask him everyday, “Do our pumps, products, and services address cost, quality, efficiency, and reliability issues?” He said the simple answer is “yes,” however, this doesn’t happen in a vacuum.

Weidmann explained that his company is experiencing seven key trends:

Speed of delivery. “The longer you wait for your pump supplier to get back to you with what you requested, the more money you lose,

“Investment in manufacturing efficiencies and getting pump selection information into the hands of customers is vital. The issue that we now face is that demand has outstripped supply. This is especially true in the case of centrifugal pumps engineered for specific applications and specifications.” 

Mergers and acquisitions. “We all see the acquisitions happening in the industry now,” he said. “The big companies get bigger and the lead times for projects are getting smaller and tighter. DXP Rotating Equipment Divisions’ ability to remain nimble and supremely focused on the engineering, manufacturing, testing, and delivery of these highly specialized centrifugal pumps remains key to our core values.”

Price. Material selection has become critical, Weidmann stated. “For example, carbon steel can save money over ductile iron,” he said. “But it’s not just about the quality of the metallurgy, it’s also about intangibles.” Companies who offer in-house engineering and testing, and extended warranties, are getting a competitive edge.

Supply and demand imbalances seem to be tightening. Most outlooks call for supply and demand equilibrium by early 2017.

Moderate demand. Global and U.S. oil demand continues to show moderate but steady growth.

LNG export. More U.S. LNG export capacity is expected to hit the market.

Cost control. Oil companies have learned how to operate in a lower-price environment, returning to a healthier focus on capital and operating cost discipline.

Weidmann said his company tackles these challenges with vertical integration of its manufacturing processes.

Vapor-recovery units

The increase in oilfield activity has also meant a corresponding increase in the amount of vapors that are created and emitted during production, transportation, and storage, according to Webb. To prevent the escape and loss of these vapors—which are saleable assets in addition to being potentially dangerous to the environment—many operators installing vapor-recovery units (VRUs) at their oilfield storage sites.

“The growth in the amount of vapors that are a by-product of oilfield production activities is not going away,” Webb said. “Neither is the attention that regulatory agencies will be paying to the levels of vapors that are emitted into the atmosphere and whether or not they can be harmful. That’s because many oilfield vapors have been classified as hazardous air pollutants or volatile organic compounds by the U.S. Environmental Protection Agency.”

Basically defined, a VRU is a system composed of a scrubber, compressor, driver, and controls designed to recover vapors that are formed inside completely sealed crude-oil or condensate storage tanks. During the VRU’s operation, the controls detect pressure variations inside the tank and turn the compressor on and off as the interior pressure exceeds or falls below pre-determined settings. When the compressor is running, it passes the vapors through the scrubber, where any liquid is trapped and returned to the tank, while the vapor is recovered and compressed into natural-gas lines.

As the oil and gas industry faces changing demand, low per-barrel prices, large supplies with varying extraction costs, and competition from renewable resources, producers are turning to manufacturers of pumps and related control equipment for increased reliability, efficient performance, and solutions for product handling and storage. Pump manufacturers are delivering, resulting in higher efficiency throughout the oil-and-gas handling process. RP

Michelle Segrest is president of Navigate Content Inc. She specializes in coverage of the industrial processing industries. Please contact her at michelle@navigatecontent.com.

124

8:52 pm
March 16, 2017
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Intelligent Water Making Strides towards Predictive Analytics

EXCEL XR metering pumps are designed for the specific chemical pumping requirements of municipal and industrial water treatment.

Last week, I ran across a Smart Water spending forecast from Bluefield Research and this week there’s an interesting post from Jim Gillespie, co-founder of Gray Matter Systems, a system integrator for cloud solutions and predictive analytics. All signs point to an increased spend in this sector for pump and motor sensors, but where will this investment come from?

According to Gillespie and his post on TechCruch, utilities may be able to sell “solutions” to other wastewater operations like the power industry has done. Gillespie cited how the District of Columbia Water and Sewer Authority has commercialized their intellectual property, giving them a new revenue channel. The water district is commercializing their water ammonia versus nitrate algorithm and selling it other treatment plants, according to Gillespie.

>> More || Smart Water Infrastructure Continues to Grow, but Real Challenges Persist

As I noted last week, new investment dollars are hard to come by but there’s are a lot of new use cases in the wastewater space, see below:

Another IIoT development, a new SaaS application that’s set to launch later this month, will calculate wastewater clarifier tank performance — providing quick analysis on a critical step in the wastewater process. The tool, called ClariFind, alerts utilities as they’re getting close to a failure before they experience it. ClariFind will predict when sludge will overflow and be released. This kind of problem causes EPA issues and fines that can run in the millions of dollars. It will also be able to predict a thickening failure, which is when the effluent doesn’t settle correctly and creates a costly sludge blanket in the tank. ClariFind is just one part of a water operations suite of productivity enhancers — solutions as a service.

Read the Full Post on TechCrunch >>


1601Iot_logoFor more IIoT coverage in maintenance and operations, click here! 

151

9:27 pm
January 13, 2017
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Improve Your Chemical-Pump Maintenance

Maintenance missteps in chemical-pumping applications can be catastrophic.

Maintenance missteps in chemical-pumping applications can be catastrophic.

Regardless of the industry, in chemical-pumping applications, it’s important to understand how the chemical reacts to heat, pressure, and flow. Just as crucial is the need to consider all system components in these applications. One maintenance misstep could be catastrophic.

Jim Raiders, senior technology engineer for Akzo Nobel Pulp and Performance Chemicals Inc., Chicago, offered the following advice for keeping chemical-processing pumps well maintained and reliable. MT

—Michelle Segrest, Contributing Editor

Common maintenance issues and solutions

• Wet-side seal integrity. Select materials and pump designs that offer improved hydraulic flow and the ability to prevent wet-area wear.

• Lubrication. Improve pump-sealing techniques to allow a wide range of operating conditions, without losing containment.

• Cavitation/inadequate flow conditions. Use self-contained lubrication systems and isolate the lubrication systems from process-chemical exposure.

• Corrosion. Use self-contained relief devices on positive-displacement pumps.

• Motor failure. Make better material selections, i.e., opt for quality materials instead of low-cost units.

• Improper mounting of pumps that creates secondary vibration nodes leading to pumping-system damage. Choose motors with improved insulation, bearings, and fan designs.

randmImportant preventive-maintenance steps

Regular inspections

Flow verifications

Vibration analysis and baselining

Power usage/thermal image baselining

Consideration of improved pump location in the process area.

Maintenance best practices

Use double mechanical seals with seal-guard monitoring for rotating pumps.

Place dosing pumps in a containment area to keep them protected from spills and sprays.

Place covers on rotating units for protection from processes.

Use power-line monitoring for loading indication of motor/pump wear.

Mount equipment properly with anchoring, grouting, and grounding.

Locate pumps in well-lit areas, if possible, for ease of monitoring.

Helpful tools

Vibration analysis

Offline and installed monitors

Thermal imaging

Process flow monitoring

CIP (clean-in-place) systems for automated cleaning when systems are offline.

For information about Akzo Nobel chemical-processing products and services, visit akzonobel.com/corporate-product/chemical-industry.

63

5:38 pm
December 22, 2016
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Maintenance Considerations For Servicing Remote Locations

Simplicity of design and availability of parts can increase the reliability and performance of chemical-processing and water-treatment pump equipment.

By Jeffrey Scott, Milton Roy

1612pumpcase02p

Water-treatment plants in rural areas strive to avoid unscheduled downtime at all costs. All images courtesy of LMI/Milton Roy.

Servicing and maintaining pumps in remote locations requires critical planning and automation.

Since 1979, Furrow Pump, has provided water-treatment equipment throughout the Pacific Northwest, in Montana, Idaho, Washington, Oregon, and Alaska. Specifically, the company provides metering pumps for potable and industrial applications, while offering design and implementation services for a range of chemical feed applications. They also provide service, repair, and maintenance services for customers located in some of the most remote corners of the United States.

When it comes to delivering chemical feed applications, Furrow offers a unique approach to each customer. In some cases, the company augments existing water treatment systems by adding specific pumps. In other cases, it designs and delivers complete solutions on skids that are assembled in its Wilsonville, OR, plant. Water-treatment applications and chemical-equipment solutions that are common across Furrow’s customer base include pH control, coagulation and flocculation, chemical neutralization and stabilization, and various measures for color and odor control.

Many of Furrow’s customers are running continuous (or near continuous) operations and many of them are in extremely remote locations. Furrow Pump president J.B. Leahy said his team is mindful of these considerations when planning predictive and preventative maintenance activities. They have identified a number of pre-sale/pre-install items that impact the pump’s efficiency, and that influence the amount of maintenance it will require throughout its lifetime.

Furrow’s customers include a mix of large industrial companies and small municipal water-treatment plants. Their constituents know a lot about their own businesses. However, they are not pump experts, so they rely on the expertise of a support network to keep their machinery running at peak efficiency.         

The industrial water-treatment side of Furrow’s business features high-tech silicon manufacturers, food processors, timber and logging companies, foundries, and oil and gas customers. All of these customers need metering pumps to manage problem areas such as scaling, corrosion, and the accumulation of microbiological activity that could diminish the quality of the products they manufacture. Once their process is complete, they also use metering pumps for pH control, and to clean wastewater prior to disposal. Many of these companies are large organizations, and some of them have their own maintenance teams.    

On the municipal water-treatment side, Furrow has carved out a niche servicing small towns in remote locations where the municipal water-treatment systems serve less than 10,000 connections. 

According to Leahy, servicing this type of market requires a high touch when it comes to maintenance. Some of these customers wear a number of different hats. “In some remote and rural areas, the city manager is also the one operating the water-treatment plant,” stated Leahy.  “But that’s fine, because our business is based on bringing expertise and reliable technology to customers who need it.”

Sizing and proper pump selection

EXCEL XR metering pumps are designed for the specific chemical pumping requirements of municipal and industrial water treatment.

EXCEL XR metering pumps are designed for the specific chemical pumping requirements of municipal and industrial water treatment.

For more than 40 years, Furrow Pump’s team has been amassing application knowledge that helps them design systems that last without excessive maintenance. Much effort is spent on analyzing application requirements, and customers are educated on the need to understand application limits, while always operating pumps at their best efficiency point (BEP).

An improper setup can substantially accelerate wear on the pump. As a simple example, chemical feed tanks should never be set below the pump. If they are, the pump will not function as though the tank were level with (or above) the pump with threaded suction. “Recognizing simple things like this can have a big impact on the longevity of systems,” said Leahy.

Because of Furrow’s expertise with many of their product lines—particularly LMI pumps—they know intimately which pumps are best suited for which jobs. It is not enough to look at a spec sheet and pick any diaphragm pump that fits the applications parameters. If the pump is sized properly, it can minimize the amount of required maintenance, which is critical for customers in remote locations.

Simplicity of design and availability of parts

Customers with limited access to repair shops should choose pumps with parts that are readily available. They should also select metering pumps that feature a simple design, where the liquid end can be easily swapped out and the diaphragm, seals, and check valves can be repaired quickly. When Furrow’s staff is alerted to a problem, they visit the customer site with parts on-hand. Their expertise with the LMI product line helps them quickly identify repair costs and estimate repair time (which in most cases is approximately an hour of bench time).

Furrow also maintains a large inventory of pumps that enables them to bring new replacement units on maintenance calls. This gives customers the option to repair existing units, or completely replace them. The ability to stock large inventories of complete pumps and replacement parts is critical for Furrow’s business.

“We’re not able to do that with every brand we carry,” added Leahy. “If it takes up to 24 hours to get a replacement part, that can cause problems for customers that run continuous operations. But that’s not an issue with the LMI product lines.”            

Dealing with off-gassing

One of the biggest issues that water-treatment applications must address is vapor locking. Chemicals like sodium hypochlorite can turn to gas when they heat up or become agitated. When a fluid gasifies, the pump can lock, causing it to stop pumping. This issue, more than any other, prompts service calls. Therefore, planning for and addressing this issue is a critical part of any effective preventive-maintenance program.

Customers should choose metering pumps with degassing valves that let gas escape in one direction and allow the process chemicals to flow as intended. Additional features such as auto-prime liquid ends, and front-scavenging technology assure high fluid velocity through the pump head and evacuate the entire liquid end with each stroke. This also helps to prevent air bubbles from accumulating and causing vapor lock.

“When it comes to dealing with vapor locking, an ounce of prevention is worth a pound of cure,” Leahy said. “In this case, it’s also worth several hours of maintenance.”         

Some of Furrow Pump’s customers are experts in making food, paper, silicon wafers, or potable water, but they are not necessarily pump experts, Leahy said. The metering pump is just a part of their machinery. Having access to a responsive network of repair technicians that can keep them up and running is the key to their success in the rural corners of the Pacific Northwest. The ability to quickly and efficiently meet these customer requirements can be a critical key to maintenance and reliability success. RP

Jeffrey Scott is part of Houston-based Milton Roy’s Global Water Team. He oversees the Western region and brings extensive application expertise to Milton Roy and LMI partners and customers. He can be reached at: Jeff.Scott@miltonroy.com. For more information on Furrow Pumps, please visit: furrowpump.com. For more information on LMI/Milton Roy, please visit: lmipumps.com.

274

5:32 pm
December 22, 2016
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Match Pump Specs to Chemicals

Marrying a specific product with the right equipment is crucial in chemical-processing pump maintenance.

This double-mechanically sealed, Plan 52 centrifugal pump is being used in a plywood-fabrication application. Photo: EnviroPump & Seal Inc.

This double-mechanically sealed, Plan 52 centrifugal pump is being used in a plywood-fabrication application. Photo: EnviroPump & Seal Inc.

By Michelle Segrest, Contributing Editor

The biggest problem a pump operator can face, especially when explosive, corrosive, and abrasive chemicals are involved is not having a structured maintenance program, according to Tim Mann, president of TKM Industries Inc., a Marietta, GA-based manufacturer of custom-engineered metering pumps for the chemical, wastewater, and mining industries.

“Sometimes the attitude is…if it works, don’t fix it,” Mann said. “This is absolutely the wrong approach. When working with chemical pumps, especially metering pumps, you are always pumping a specialty chemical. You have to be mindful of the product you are pumping because every chemical gives you a different problem. Many of them can be reactive to heat and pressure, for example. You have to design your maintenance program around those specifics.”

Chemicals that are non-viscous and non-corrosive may only require minimum scheduled maintenance, while those that are more aggressive require more frequent maintenance. “It’s important to consider the pump and the product you are pumping when designing the maintenance program,” Mann said. “It’s not one-size-fits-all. Every chemical creates a different challenge.”

Chemical-pump maintenance

To avoid some of the most common maintenance issues that occur in chemical-processing pumping systems, EnviroPump & Seal Inc.’s Monik Gandhi suggests insisting on a proper design from the beginning, ensuring a proper installation, and maintaining the pumps according to a strict schedule. EnviroPump & Seal Inc., Marietta, GA, is a manufacturer of ANSI process pumps and mechanical seals.

The top six maintenance issues and their solutions include:

Faulty or incorrect design. Verify the manufacturer’s recommendation using their pump curves and pump data sheets prior to purchase, Gandhi suggested. “Verify materials of construction used in the pump for any incompatibility. If the manufacturer has a distributor or manufacturer’s representative in the area, use them as a third party to verify the conditions of service required versus the pump curve and data sheets provided by the pump manufacturer.”

Manufacturing error. Look for pumps with the longest warranties or pump manufacturers with good references. “Those manufacturers that offer the longest warranties generally have more procedures in place to assure that the pump runs properly and efficiently for a longer time,” Gandhi said. “The standard pump warranty is for one year. Look for those manufacturers that offer warranties that are longer than that. The longest warranty currently available on a pump is three years.”

Assembly/installation errors or defects. Hire a millwright, or use the millwright who is staffed by the customer. “Follow all the manufacturer’s recommended installation and startup procedures,” Gandhi suggested. “Pay special attention to alignment, rotation, shimming, etc.”

“Live” process conditions different from base design. “This is a difficult problem to solve,” explained Gandhi. “It is looked at on a case-by-case basis. In some instances, the impeller trim can be changed, or the speed of the pump (among a list of other things). In other instances, the process flow is too different from the designed pump, and the pump must be replaced with a pump which can attain the desired conditions.”

Maintenance deficiencies and procedure neglect. Keep a daily check on all maintenance items (even those with instrumentation designed to alarm at a central location), Gandhi recommended. These items can include considerations such as cooling-water flow and basket-strainer cleaning.

Improper operation or operation not intended for the pump. Certain pump technologies can be used for only certain process streams, Gandhi said. “For instance, if you want a high turndown, you should use a pump which can acquire that, such as a peristaltic pump or a solenoid pump. If you want a pump that can pump very viscous materials, then a positive-displacement pump is the right solution. If there is high heat involved, then cooling accommodations must be made for the pump seals. If the wrong technology is used for the wrong process, the pump will never perform as needed by plant personnel. It is a good idea to do some industry research and/or rely on someone who is versed in the technologies to steer the customer toward the proper solution.”

A VIT-1000 centrifugal pump keeps product moving at a leading snack food manufacturer’s plant. Photo: EnviroPump & Seal Inc.

A VIT-1000 centrifugal pump keeps product moving at a leading snack food manufacturer’s plant. Photo: EnviroPump & Seal Inc.

Marrying chemical and equipment

All chemicals present specific challenges, making the marriage of the pump and the product it’s pumping of utmost importance, Tim Mann stated.

“Chemicals react differently at different speeds and pressures, and they also react differently depending on the type of pump,” he explained. “If you are using a progressive cavity or gear pump, for example, when they are spinning fast they create heat. Some chemicals don’t react well to heat, or they may be shear sensitive. By turning that kind of pump, you can create another kind of problem. The heat can cause the chemical to break down and, when this happens, it reacts in different ways. It could become sticky or more viscous or more abrasive, or less effective…it just depends on the chemical.”

Mann described a situation years ago when one of his customers made a slight formulation change to a chemical it was pumping. “We were using a gear pump that normally would last at least two years without any issues. This slight change caused the pump to break down at an alarming speed. We worked hard to figure out the problem and finally learned that the change in the chemical had caused it to become more reactive to heat, which was causing abrasion, which was wearing on the pump. We had to select a different piece of equipment and totally redesign the system to suit the product. Then the maintenance team had to determine a new maintenance schedule.”

According to Mann, the marriage of the pump and the chemical also relies on a strong partnership between the manufacturer and the operator.

“The technologies are changing so fast, and the chemical companies are always looking for an edge to make a better chemical,” he said. “Just a little bit of change in the formulation will cause maintenance and wear issues you didn’t expect. We work closely with the customer to make sure we understand the chemistry and which pump will work best with it. If I have any doubts, I always recommend a different pump to the customer. Marrying the equipment with the chemical is essential. If you don’t do it right, you are setting yourself up for failure.”

That symmetry extends to the components as well.

“It’s not just the pump,” explained Mann. “You have to also ensure the piping is running properly. The valves may need pulsation dampeners or relief valves. The pump requires maintenance, but so do all the other components. You have to be sure they are all functioning properly.”

Other considerations come into play. Some chemicals may create an off-gassing effect or introduce vapor in the lines, which can cause blockage. If vapor lock occurs, the pressure-relief valve must be working properly or the pump will be damaged or destroyed, Mann said.

Mechanical-diaphragm pumps use sodium hypochlorite to disinfect drinking water. Photo: Guardian Equipment, Sanford, FL

Mechanical-diaphragm pumps use sodium hypochlorite to disinfect drinking water. Photo: Guardian Equipment, Sanford, FL

Maintenance best practices

There is much education and critical research needed to maintain chemical-processing pumps. Chemicals are used in a variety of pumping applications, including wastewater, water, food and beverage, pulp and paper, oil and gas, pharmaceutical, and almost all other processing industries. The details matter, said Mann.

“When people talk high-tech, they think iPods or iPhones or electronic gadgets,” Mann said. “The chemical industry is very high tech and cutting edge. Chemicals have become much more active. Everyone is looking for an added advantage. When they do this, they often change the chemical. Sometimes the chemical companies provide the equipment because it’s always changing.”

This requires asking detailed questions, such as:

— What is the viscosity?

— What is the compatibility of materials?

— What is the specific gravity?

Answers to questions such as these can help to determine the right pump for the application. This leads to proper preventive-maintenance programs.

“You have to know your chemical,” Mann reiterated. “Customers and users should share all the information they can with the manufacturers. It’s a two-way street. We can’t walk in and tell the customer we understand everything about their chemical until we’ve taken the time to learn their chemical. At the same time, they don’t know 100% if your equipment is going to work to move that chemical unless they fully understand the type of pump and everything about it. In a metering pump, for instance, maybe you need a chemical that is more abrasive, so you want to use a harder metal component. This could increase the cost. It’s important to have this communication. It will save you unplanned maintenance down the road.”

It’s always a tradeoff between scheduling cost and time, Mann said.

“Some companies specialize in pumping certain chemicals. Some specialize in slurries. Others may pump a very clean, non-viscous material, close to water. Our plunger pump can pump very viscous materials, for example. Polymers are everywhere. But polymer is a very generic term. The type of polymer and the viscosities can vary greatly. We know we can pump this type of chemical without a problem. So some companies come to us for that specific reason.”

While the specifics are important, there are some common preventive-maintenance best practices, Gandhi said. “There are many things maintenance personnel can perform as preventive maintenance for the pumps in service as well as any spare units that may be in storage,” he explained. “Spares should be manually turned once every few weeks, keep all moving parts lubed to prevent lock up and rust.”

In Gandhi’s opinion, the most overlooked preventive-maintenance practice is to use common sense and all your senses.

“For a few minutes every day, it helps if a maintenance worker looks at the pump for items such as vibration or leaks, while listening to the pump for items such as cavitation or misalignment,” offered Gandhi. “Most of the issues that can arise with pump maintenance can be caught ahead of a catastrophic failure if the pump is monitored closely. In addition to eyes and ears, there are many forms of instrumentation that can remotely monitor critical elements of the pumping system.”

Technology, tools, tips

Mann and Gandhi recommended taking advantage of the many tools available to help with chemical-pump maintenance.

“There is a plethora of instrumentation that can help monitor your pump,” Gandhi said. “The most catastrophic pump failures can be caught before they become fatal to the pump. In addition to instrumentation, a daily visual/auditory check of all rotating equipment will increase pump life because the evaluator will see a problem when it is still manageable instead of when it becomes out of hand and the pump needs to be replaced.”

It’s important to use instrumentation. However, users should not to rely too much on technology, Mann suggested. “You can use a pressure gage or flow meter, but always feed back into the DCS or SCADA system and use the information to do your statistical process controls to [identify] your maintenance issues. Sometimes alarms go off so much and they are ignored and you don’t even hear them anymore. You see this all the time. In the control room an alarm goes off and the guy just reaches over and kills the alarm.”

Mann offered these additional tips:

— Ensure everything is working properly. “Routine checks make all the difference,” he said. “If you just follow the procedures, the equipment will last much longer. Less work, less money, less time. All good.”

— It only takes a minute to look at a gage or a pressure valve, so do not overlook this important step.

— Always make sure your safety procedures are in place and are followed.

— Be sure you have good preventive maintenance (PM).

— When you have shutdowns, make sure you properly clean the pumps and pipes.

— Make sure you are using good parts—the recommended parts—and that you have spares on hand.

— Always be ready to realize that it’s not just the pump, it’s the entire process line that needs maintenance. Take care of all the components.

— Have a checklist. If plants are running well, personnel generate good checklists and they follow the checklists. This will save you time and money and the equipment will run more smoothly. “PM doesn’t have to mean you have to tear the equipment down 100%,” Mann said. “PM may be just checking to make sure the oil levels are correct or everything is working. You may look at a pressure gage and everything is working fine but the pump has to work harder to keep the same pressures.” 

— Avoid complacency. Is someone checking to be sure the filter baskets are being cleaned as scheduled? Those kinds of small things can cause big problems. Some people don’t think they need a pressure-relief valve, so they just take it out or never check it because it always works.

— Don’t cut corners. Pay attention to the details.

“In the end, it is common sense,” Mann said. “It’s putting the procedures in place, and then following them.”

Mann described how overlooking something simple can cause dangerous problems when pumping chemicals.

“When I first started working in the industry, I was in a plant and an operator said he needed to change the filters,” Mann explained. “I was looking at it, and the gage was reading 50 psi. I asked him if we needed to relieve the pressure. He said no, because that gage doesn’t work… ‘It’s never worked,’ he said. I was skeptical enough that I backed up. He opened the filter and a chemical came pouring out and totally drenched him.

Fortunately it wasn’t an aggressive chemical, but it could have been. It was all over him. If he had checked the gage to see if it was working, and if he had been cleaning the filter baskets regularly, just routine maintenance, this would have been avoided. He did everything wrong. And he learned the lesson the hard way. It could have ended really badly. The only thing he did right was he was wearing safety glasses. The chemical ruined his clothes, but he was so lucky.”

Gandhi emphasized this point when he described a challenging maintenance issue.

“At one plant the seals on the centrifugal pump would continually fail within a week,” Gandhi said. “The pump was moving 450-degree thermal oil. The seals would overheat, and eventually fail. We decided to go with a Plan 52 cooling arrangement. We put cooling jackets on either side of the seal, as well as injected a barrier fluid (cooling as well) in between the seals. This greatly increased the run-time between failures for this particular plant.”

When working with chemicals, OSHA requires that every chemical supplier provide a Materials Safety and Data Sheet (MSDS). These can also be found online and will tell you whether a chemical is harmful/corrosive and provide additional information. This will help the operators  understand the chemicals and their potential hazards, but maintenance plans should be customized and flexible, Mann stated.

“A chemical pumping-maintenance plan is not something you create and then it’s good forever or works for every piece of equipment,” he said. “It’s always changing. In most plants, the chemistry is constantly changing. Everyone is always looking for a better way. You can’t create a maintenance plan and put it on the shelf and forget about it. It’s not that simple.”

Mann recommends creating a good work history to avoid reinventing the wheel on common problems. “You may fix one problem and create two more,” he said. “And, if it’s a really common problem, then you are not really fixing it.” RP

Michelle Segrest has been a professional journalist for 27 years. She specializes in the processing industries, and can be reached at michelle@navigatecontent.com.   

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6:02 pm
November 15, 2016
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Mechanical-Seal LCCs Hold Savings

Mechanical seals may represent the largest cost of operation in some facilities and their reliability is a direct proxy for overall pump reliability.

Mechanical seals may represent the largest cost of operation in some facilities and their reliability is a direct proxy for overall pump reliability.

The result of good reliability engineering is elimination of field failures, yet making the connection between reliability and prevention of these failures is not always obvious, according to Lloyd Dewey Lee, Jr., CMRP, MBA, CRL, Reliability & Asset Management SME, FacileX, Knoxville, TN.

During his presentation at the 24th Annual SMRP Conference in Jacksonville, FL, in Oct. 2016, Lee said communication issues that many reliability personnel have with management can limit exposure to justification of their programs.

He posed the question, “How does one show and promote the ongoing contribution to ROI to justify the reliability program?” A quick answer is that one of the biggest, most overlooked, contributions to maintenance costs for pumps (which are also one of the most prevalent equipment types found in manufacturing plants) is the mechanical seal.

Mechanical seals (depending on their piping plans) may represent the largest cost of operation in some facilities, and their reliability has a direct impact on overall pump reliability. Because of these factors, reliability personnel should be aware of the life-cycle costs (LCCs) of these seals.

randmTotal cost of ownership (TCO) involves, at a minimum, five factors:

Design — This includes considerations such as expected design life and service criticality. Studies show that as much as 80% of machinery reliability is determined in the design phase.

Acquisition — The acquisition cost of an individual mechanical seal is dependent upon many variables, including metallurgy, elastomers, shaft size, cartridge or single-spring type, face materials, whether it has single or double faces, and any ancillary equipment needed for a flush plan. Acquisition costs aren’t significant, compared with operational costs. Implementing an alliance program with a seal vendor can improve acquisition costs.

Operation — Far and away the costliest component of mechanical-seal usage is in the operation. This is where the real savings to LCC can be achieved. Numerous factors affect pump reliability from an operations point of view. Once operational life is underway, the optimum life of the pump and system will only be realized if the pump is operated near its best efficiency point (BEP).

Maintenance — The opportunity for repair should be viewed as a maintenance upgrade event. For example, an analysis of pump curves may reveal that a change in the impeller size could move the pump closer to its BEP. With regard to mechanical seals, it is a normal practice to remove the entire seal, document the failure mode on a travel ticket, and send the seal either to the seal manufacturer for an analysis and/or execute a core return if the plant is under an alliance contract.

Disposal — Failed mechanical seals are among the most frequent reasons for removing pumps from service for repairs. That’s because leaks are obvious visual evidence of a failure. Impending seal failure may also be indicated if pressure, temperature, or level-gauge alarms on ancillary equipment are active.

Single-face seals leak along one of five paths (dual-face designs have similar static and dynamic leak paths:

Seal face leakage is visible at the shaft exit of the gland or at the drain connections.

Dynamic secondary seal leakage is also visually noticeable where the shaft exits the gland or at the drain connections.

Static secondary seal leakage is visible at the point where the shaft exits the gland or at the drain connections.

Gland gasket leakage is visible at the gland-seal chamber interface.

Hook-sleeve gasket leakage or cartridge-sleeve secondary seal leakage is visible at the point where the sleeve ends outside of the seal chamber.

Number-crunching is essential to capturing equipment ROI. Many companies have not performed a thorough cost-benefit analysis on the preventive-maintenance function. Therefore, it is difficult to analyze, with financial credibility, the cost of preventive-maintenance tasks and the contribution of the reliability program to reducing costs.

Thus, reliability and maintenance personnel should understand and be able to apply key financial concepts regarding return on investment (ROI). Common methods for analyzing payback include:

Net Present Value (NPV) — The total present value (PV) of a time-series of cash flows.

Investment Yield — The internal rate of return (IRR) for an investment is the discount rate that makes the net present value of the investment’s income stream total to zero.

Payback Period — The time it takes the cash inflow from a capital investment project to equal the cash outflow is typically expressed in years. The payback period is a simple and well-understood metric by most personnel because it simply calculates the length of time for the cash flow or savings generated by the project to pay back the project’s cost.

Cost of Capital — This is an important financial metric to understand when discussing the payback on an investment. It is not unusual for an organization to use its weighted average cost of capital (WACC) as a discount, or “hurdle,” rate in the payback evaluation of capital expenditures. MT

—Michelle Segrest, contributing editor

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6:43 pm
October 15, 2016
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Hands-On Training Takes Center Stage at Geiger Mid-Atlantic Pump & Process Equipment Symposium XI

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geiger-symposium-logoCan you say “beehive of activity?” That’s what 830 Tryens Rd., in Aston, PA was like on Thurs., Oct. 6. 2016. It’s where 300+ industry professionals, representing more than 100 end-user organizations and leading suppliers, gathered for the Geiger Mid-Atlantic Pump & Process Equipment Symposium XI.

Maintenance Technology’s managing editor Jane Alexander and contributing editor Michelle Segrest were on the ground with the large crowd that included personnel from operations such as Dow, DuPont, D.C. Water, GAF, DELCORA, Air Liquide, Exelon, the U.S. Coast Guard, Kinder Morgan, American Sugar Refining, The Hershey Co., Perdue, Buckeye Partners LP, Chemours, Westway Group, Johns Manville, and Veolia Water; and vendors such as ITT Goulds Pumps, Viking Pump, Weir Specialty Pumps, Blacoh Surge Control, John Crane, Westech, and Verder.

logoPresented every two years by well-known industrial distributor Geiger Pump & Equipment (geigerinc.com), which has facilities in Aston and Baltimore, these popular day-long events feature a full slate of pump and process-equipment training (much of it hands-on); product displays; and plenty of food, drink, and networking. The 2016 installment didn’t disappoint.

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This special issue of Maintenance Technology was distributed to all attendees at the symposium. You can download a pdf version here.

From the start of this symposium series through this year, these free Geiger events have always attracted a wide range of attendees from end-user sites across the region. One of the biggest draws is the practical, expert-led, hands-on training that they incorporate. It’s an effective workforce-development and refresher model that’s very much needed, but not available everywhere. As an example, Geiger president Henry Peck and his team point to having trained more than 2,000 (unique individual) pump and process-equipment pros in this manner—just since 2004. Some individuals and teams, though, have returned more than once.

Classes at Symposium XI included hands-on exploration of pumping-system optimization, centrifugal pump maintenance, and installation and maintenance of mechanical seals. The breakdown on attendees included the fact that:

  • nearly 75% were first-timers
  • roughly 2/3 were from Industry, and 1/3 from municipalities or related consulting-engineer groups
  • more than 50% had 10+ years experience in their field
  • 67% were in plant operations and maintenance
  • almost 25% were in either plant process or consulting engineering.

To learn more about the day’s activities and also pick up some helpful equipment-maintenance tips, check out the videos and photos on this page.

Hands-on was the key learning tool at the Geiger Mid-Atlantic Pump & Process Equipment Symposium XI, held Oct. 6, 2016 in Aston, PA. Above are several images of attendees in action during the day. Images provided by Craig Fuller.

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