Archive | Pumps

98

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

244

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.

57

2:28 pm
October 12, 2016
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Steady Pumping Equals Creamy Ice Cream

Ice cream mixes raise the requirements for volumetrically consistent pumping technology.

Faced with new recipes that were taxing the efficiency of the centrifugal pumps used in its manufacturing process, Ysco, a producer of private-label ice cream, knew that it needed a better pumping solution. With the help of engineering assistant Krist Levrouw (pictured), the company found a solution with the SLS Series eccentric-disc pump from Mouvex.

Faced with new recipes that were taxing the efficiency of the centrifugal pumps used in its manufacturing process, Ysco, a producer of private-label ice cream, knew that it needed a better pumping solution. With the help of engineering assistant Krist Levrouw (pictured), the company found a solution with the SLS Series eccentric-disc pump from Mouvex.

By Sueli Roel Backes, Mouvex and PSG

Most people are familiar with the 1920s novelty song titled “Ice Cream,” with its instantly recognizable refrain: “I scream, you scream, we all scream for ice cream.” All these years later, consumers still scream for their favorite dessert choice.

There is, however, screaming that is not desirable when it comes to discussing ice cream. These are the howls of frustration that can be heard coming from ice cream manufacturers who are confronted with an underperforming production process that is adversely affecting expected high product quality. Specifically, an inconsistency of flow rate, pressure, and speed when transferring mixes during production could result in the formation of ice crystals that are too large, which compromises the end product’s taste, visual appeal, and creamy sensation.

Ice cream production is actually a relatively straightforward process. An ingredient mix is pumped through a pipeline to a double-wall tube or tunnel freezer that is chilled by liquid ammonia to –22 F (–30 C). Inside the freezer, a slow-turning agitator, or scraper, forces the mix outward, where it briefly touches the frozen outer wall before it is turned back inward. This is when the ice crystals, which eventually become ice cream, are formed.

To achieve the required taste and expected creamy “mouth feel,” the ice cream mix can only spend a highly regulated amount of time in contact with the freezer’s outer wall. This is why the transfer flow and pressure have to be so accurate.

“If, during the transfer to the ice cream freezer, the flow is pulsating, then the time the mix spends on the wall isn’t under control,” explained Peter Van de Sompel, manager, Bellux for Spin Pompen, an Assen, The Netherlands-based specialized distributor of pumps and related equipment for use in the food, beverage, and pharmaceutical industries.

“When the flow is constant and optimized to the freezer requirement, then the ice cream coming out of there will have ice crystals that are impossible to detect by the eye and impossible to taste. It should be like a cream and solid at the same time, that’s what makes good ice cream.”

Achieving proper production within the freezer was once relatively easy. That has changed over the years, however, as ice cream has evolved from traditional compositions, such as vanilla, chocolate, and Neapolitan, to much more complicated recipes that can include flavors, nuts, and chunks of fruit or candy.

Not only does the SLS Series pump offer the standard features for which Mouvex eccentric-disc pumps have long been recognized, but the design has helped it earn approval from EC 1935/2004, along with 3A, FDA, and EHEDG, for use in food-processing applications.

Not only does the SLS Series pump offer the standard features for which Mouvex eccentric-disc pumps have long been recognized, but the design has helped it earn approval from EC 1935/2004, along with 3A, FDA, and EHEDG, for use in food-processing applications.

Mix makeup and viscosity

The combination of a strict manufacturing process and a change in the makeup and viscosity of the ice cream mixes has brought into question the effectiveness of the pumping technology that has been traditionally used in ice cream manufacture, namely centrifugal pumps.

“The ice cream freezer is very sensitive. It has to be fed with continuous pressure, which has to be maintained in a very narrow range,” said Van de Sompel. “That’s why the centrifugal pump was a good solution. But with higher viscosity you need a volumetric pump with a very stable flow that can be regulated in a very linear way. If you look at that, you need a pump with an equal flow and a 1:1 ratio of flow to speed.”

One company that has mastered the production of ice cream over the years is Ysco, Langemark, Belgium, which, since 1949, has been a major player in the production of private-label ice cream products for retail chains. From its production facilities in Langemark and Argentan, France, Ysco annually produces 41.2 million gallons (174 million liters) of ice cream in the form of 0.26 to 1.3-gallon (1- to 5-liter) tubs, cones, molded and extruded sticks, cakes, and small cups. That volume resulted in sales of more than $244 million (245 million euros) in 2015.

Ysco is part of Milcobel cvba, Kallo, Belgium, a farming cooperative that was formed in 2004 with the merger of BZU Melkaanvoer and Belgomilk. Today the cooperative collects, processes, and commercializes milk from 2,800 dairy farms, and is becoming Belgium’s largest dairy group. Ysco’s ice cream production accounts for 22% of Milcobel’s annual production volume.

The changes in ice cream recipes, however, were beginning to hamper Ysco’s ability to reliably produce finished products that met its demands and those of its customers. Namely, the higher-mix viscosities were incompatible with the operational capabilities of the centrifugal pumps being used to transfer the mix from the preparation vessels, through the pipelines, and into the ice-cream freezers.

That prompted Krist Levrouw, an engineering assistant who has been employed at the Langemark facility for 26 years, to initiate a search for a better pumping solution. “The classic centrifugal pump solution does not work properly with mixes in excess of 500 cP, often as high as 2,500 cP,” said Levrouw. “Under these circumstances, centrifugal pumps are unable to generate the pressure required to transfer the mix and feed the freezer properly. As a result, you can’t empty the vessels completely and you have too much waste.”

Flavor of the day

Some years ago, Ysco’s Argentan facility had begun using C Series eccentric-disc pumps from Mouvex, Auxerre, France, a product brand of PSG, a Dover company, Oakbrook Terrace, IL, USA, for its liquid-transfer operations. In talking to his colleagues at the Argentan plant, Levrouw learned of the success they had been experiencing with the Mouvex pumps, and reached out to Spin Pompen to see if they could suggest a solution for his needs.

“Of course, we knew that the Mouvex technology would solve his problem, which was covering the distance between the tanks and the ice cream generator in a controlled way, with constant flow and no pressure peaks, so that the product characteristics were respected,” added Van de Sompel.

The challenge was considerable because of the layout of the Langemark facility. The supply tanks are located unusually far from the ice cream freezers—720 ft. (220 m)— and that distance was putting additional strain on the centrifugal pumps. “If you’re pumping ice cream over 220 meters you don’t want pulsation, which will cause pressure peaks, which is not very beneficial for the generation of ice cream,” said Van de Sompel.

Addressing these operational challenges, Van de Sompel recommended to Levrouw the seal-less Mouvex SLS Series eccentric-disc pump. SLS Series pumps have been designed specifically for operation in food-and-beverage manufacturing applications. The seal-less design is ideal for hygienic applications because it reduces the risk of product contamination and leaks while avoiding messy spills, waste, and product spoilage.

The stainless-steel pumps feature a design that incorporates a double-wall bellows and pressure-switch monitoring. By mounting the pressure switch on the bellows flange, the bellows become an independent sub-assembly within the pump, resulting in easier and safer operation. The design has helped the SLS pumps get the required certifications from EC 1935/2004, 3A, FDA, and EHEDG, for use in food-processing applications. Because the pump has only two wear parts, maintenance is easy and can be performed while the pump is online.

Along with these advancements, the SLS Series pumps offer benefits for which Mouvex eccentric-disc pumps have long been recognized, including low shear rate, very low pulsation, very low slip, self-priming and dry-run capabilities, exceptional volumetric consistency, repeatability, and clean-in-place (CIP) capability.

“The reality for ice cream manufacturers is that one day they have ice cream mix as milk, then the next day they might have ice cream as thick as 500 cP, up to 2,500 cP,” said Van de Sompel. “The Mouvex pump shows very limited variation in flow rate under varying conditions of pressure and viscosity.”

“The pump is idiot proof, which is very important since we are running 24 hours and everyone has to handle it,” said Levrouw. “If the pump is too difficult to clean and maintain, then it’s a problem. It will be destroyed in a short time. Every step is complicated, but the Mouvex pump makes life easier. No stress.” RP

Sueli Roel Backes is with the Food & Beverage division of Moulvex, PSG. U.S. headquarters are in Oakbrook Terrace, IL. Backes can be reached at sueli.roel@psgdover.com.

20

2:20 pm
October 12, 2016
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Food-and-Beverage Pump Quick Facts

All pumps in food-and-beverage processing applications should meet the minimum Food and Drug Administration (FDA), Washington, requirements for materials of construction (fda.gov). Depending on the application, process use, and local plant sanitary guidelines, pumps may also have to meet 3-A Sanitary Standards (McLean, VA, 3-a.org) approval. On this page is a collection of facts and source information related to food-and-beverage pumping.

Food & Beverage Pumps Toolbox

This list contains the basic tools needed to maintain food-and-beverage processing pumps:

  • backstops
  • motor thermostats
  • run-dry and dead-head protection
  • detailed equipment specifications (one size does not fit all)
  • temperature gauges
  • electronic thermometer
  • variable-frequency drives
  • variable-speed drives
  • sprag (to ensure proper rotation)
  • tachometer
  • inductive tachometer
  • tape for shafts with reflective strip to read temperatures
  • cleaning chemicals.

Hygiene & Safety Standards

The hygiene and safety standards in the food-and-beverage industry have risen sharply in recent years. Pumps are used in almost all product processes and need to meet increased requirements for:

  • gentle handling, cleaning, and sterilization
  • absolute hygiene in all processes
  • operational safety, ease of maintenance.

Source: SEEPEX.com

3-A Sanitary Standards

3-A SSI, McLean, VA, is an independent, not-for-profit corporation dedicated to advancing hygienic equipment design for the food, beverage, and pharmaceutical industries. It represents the interests of regulatory sanitarians, equipment fabricators, and processors, three stakeholder groups with a common commitment to promoting food safety and the public health.

Today, 3-A SSI is an independent corporation dedicated to education and promoting food safety through hygienic equipment design in the rapidly changing food, beverage, and pharmaceutical industries.

Source: 3-a.org

FDA’s FSMA

The FDA Food Safety Modernization Act (FSMA), the most sweeping reform of food-safety laws in more than 70 years, was signed into law by President Barack Obama on January 4, 2011. It aims to ensure the U.S. food supply is safe by shifting the focus from responding to contamination to preventing it.

The public-health imperative:

  • Foodborne illness affects 48 million (1 in 6) Americans each year, hospitalizing 128,000 and killing 3,000.
  • Immune-compromised individuals (infants and children, pregnant women, elderly, those on chemotherapy) are most susceptible.
  • Foodborne illness is not just a stomach ache. It can cause life-long chronic disease, such as arthritis and kidney failure.

Why the law was needed:

  • Globalization has resulted in importing 15% of the U.S. food supply.
  • The food supply is more high-tech and complex with more foods in the marketplace and the introduction of previously unseen hazards.
  • About 30% of the population is especially at risk for foodborne illness.

Impact of the law

  • Creates a new food-safety system
  • Broadens the prevention mandate and accountability
  • Installs a new system of import oversight
  • Emphasizes partnerships
  • Emphasizes farm-to-table responsibility.

Source: fda.gov

Food-and-Beverage Pumps Market

In a recent report, Transparency Market Research (TMR), Albany, NY, estimates that the size of the global positive-displacement (PD) sanitary pumps market was $4.55 billion in 2015. TMR expects the market to expand at a CAGR (compound annual growth rate) of 10.1% from 2016 to 2024 and rise to a valuation of $10.65 billion by 2024. In terms of the varieties of rotary PD sanitary pumps available in the market, gear pumps accounted for more than 32% of 2015 market revenues in 2015.

(Source here.)

The EHEDG

The European Hygienic Engineering & Design Group (EHEDG.org), Frankfurt, Germany, is a consortium of equipment manufacturers, food industries, research institutes, and public health authorities, headquartered in Frankfurt, Germany. It was founded in 1989 to promote hygiene during the processing and packing of food products by improving hygienic engineering and design in all aspects of food manufacture.

96

2:13 pm
October 12, 2016
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Clean is the Top Food-Pump Priority

Food-and-beverage pumps are subjected to extensive and harsh cleaning procedures to assure that they meet all health regulations.

Wilden PS8 Saniflo FDA pumps (Wilden Pumps, Dover PSG, Oakbrook Terrace, IL) equipped with the Pro-Flo SHIFT air-distribution system and a full-stroke integral piston diaphragm provide maximum cleanability and energy savings for cap irrigation at Rodney Strong Vineyards, Healdsburg, CA. Photo courtesy Wilden.

Wilden PS8 Saniflo FDA pumps (Wilden Pumps, Dover PSG, Oakbrook Terrace, IL) equipped with the Pro-Flo SHIFT air-distribution system and a full-stroke integral piston diaphragm provide maximum cleanability and energy savings for cap irrigation at Rodney Strong Vineyards, Healdsburg, CA. Photo courtesy Wilden.

By Michelle Segrest, Contributing Editor

It can be as smooth and clear as water or wine, or as sticky and thick as cookie dough or peanut butter. Regardless the viscosity, one thing remains a top priority when pumping processed food and beverages—no corners can be cut when it comes to keeping the systems clean and hygienically safe.

“Keeping this equipment sanitary is no joke in our business,” said Mike Dillon, president of SEEPEX Inc., an Enon, OH, manufacturer of pumps that process milk and dairy products, wine and beer, fish, baking goods, sugar, fruit and vegetables, poultry and meat, and other food products. “I have seen manuals for one company that are more than 200 pages of procedures just for keeping the equipment clean. The guidelines are strict, and they should be. On every changeover, and also during production, we must ensure that this equipment is completely flushed of any bacteria or other residual material.”

Until the 1950s, closed systems were completely disassembled and cleaned manually after every shift and changeover. The advent of clean-in-place (CIP) procedures changed the industry. CIP is a method of cleaning the interior surfaces of pipes, vessels, process equipment, and associated fittings while the equipment remains online. Industries that rely heavily on CIP are those requiring high levels of hygiene, including dairy, beverage, brewing, processed foods, pharmaceutical, and cosmetics.

CIP is faster, less labor intensive, and more repeatable than COP (clean-out-of-place), which requires complete disassembly of the production line to clean it properly. CIP also poses less of a chemical-exposure risk to people. It started as a manual practice involving a balance tank, centrifugal pump, and connection to the system being cleaned. Since the 1950s, CIP has evolved to include fully automated systems with programmable logic controllers, multiple balance tanks, sensors, valves, heat exchangers, data acquisition, and specially designed spray-nozzle systems.

In addition to advanced CIP practices, this is an industry that is heavily and strictly monitored by many governing bodies, including, but not limited to:

  • Food and Drug Administration (FDA), Silver Spring, MD
  • European Hygienic Engineering & Design Group (EHEDG), Frankfurt, Germany
  • 3-A Sanitary Standards, McLean, VA
  • United States Dairy Association (USDA), Washington
  • National Sanitation Federation (NSF), Ann Arbor, MI
  • County, state, and federal health inspectors
  • U.S. Environmental Protection Agency (EPA), Washington.

Most large food-and-beverage manufacturers must have representatives from one or more of these agencies on site any time their equipment is running to perform scheduled and random checks of the sanitary discrepancy of the equipment.

Cleaning of plant process equipment, pumps, valves, heat exchangers, tanks, vessels, mixers, and other equipment with the proper chemicals and methods is determined by the individual plant’s sanitary departments. Some systems still use the COP method, while some food pumps are designed for sterilization-in-place (SIP), which provides sterilization with superheated steam during the cyclic operation of the pump.

A major beer manufacturer was having issues with the consistency of its finished product and was looking for a pump for its critical yeast-food and hop-color-dosing application process. The problem was solved by upgrading to Mouvex SLS Series pumps, manufactured by Mouvex Pumps, Dover PSG, Oakbrook Terrace, IL. The pumps use no seals and are highly reliable, volumetrically consistent, easy to clean, and require low maintenance. Photo courtesy Mouvex.

A major beer manufacturer was having issues with the consistency of its finished product and was looking for a pump for its critical yeast-food and hop-color-dosing application process. The problem was solved by upgrading to Mouvex SLS Series pumps, manufactured by Mouvex Pumps, Dover PSG, Oakbrook Terrace, IL. The pumps use no seals and are highly reliable, volumetrically consistent, easy to clean, and require low maintenance. Photo courtesy Mouvex.

Common CIP examples

Dillon explained that, before CIP was common practice, the procedure was much more complex.

“The way it used to be in dairy, for example, you would show up for your shift, run your process, and then you would tear down everything—all the piping, tri-clamp fittings, and the pumps,” Dillon said. “The shift that was leaving took all the parts and put them in these big cleaning troughs where they had to use bottle brushes to clean out the pipes. The next shift had to do all the cleaning and all the reassembly. Everything that was produced on the shift had a number on it to trace it to that shift. If, for some reason, salmonella, or something like that, showed up, they could eliminate or call back all the production on that shift.”

CIP processes are similar, but without the disassembly. “With CIP, they don’t tear down everything, but there is a series of chemical flushes,” Dillon explained. “They use high-speed, high-volume centrifugal pumps because you have to get up to seven feet per second in velocity on the cleaning chemicals for them to do their job. They also run at very high heat. They are going to run caustic soda at really high flow rates through the entire line, and they also run nitric acid through it to kill everything. They finally finish it off with hypochlorite solution to sterilize it,” he added.

This is typically performed at 180 degrees Fahrenheit for about 90 minutes, Dillon stated. “Some of these guys think hotter is better. Some procedures are so severe that if you had a dead mouse in the line it would be dissolved. It’s pretty rough. It is a very aggressive chemical at very high temperature, and it is designed to kill everything that is in that line.”

This means the pipes must also be able to handle the abrasiveness of the cleaning materials.

“You have to be so careful,” Dillon said. “You can’t run the equipment normally the way you run it during CIP. If you do, yogurt, for example, may come out looking like skim milk. You must change the operation parameters between CIP and regular operation.”

USDA and FDA inspectors may be on site to determine the cleanliness of the system after each CIP. “They don’t care how you clean it, but it must be cleaned to their standard,” Dillon said. “If you are in a dairy plant, you must clean the system at least three times a day. Other products, for example chocolate, have less-stringent regulations. It just depends on what you are pumping.”

Inspectors will take samples and record bacteria counts. “The food industry in this country is incredibly regulated,” Dillon said. “You may have five or six different regulators coming into your plant unannounced. So the procedures must be strictly written and followed.”

The USDA and FDA have set procedures for what will kill bacteria, Dillon said, and it is all based on temperature and time. “The sterilization procedure for CIP is 176 degrees Fahrenheit for 12 minutes. This ensures that anything such as salmonella is dead. Some guys will take it to 220 degrees because it’s in a pressured system, just to see what happens, but this is not a good idea. The problem is this extreme heat can hurt some of the other materials, like rubber, for example. Thinking hotter is better is a common problem. Dead is dead. Bacteria doesn’t need to be deader than dead.”

Once the equipment is flushed with the chemicals, it is then flushed with clear water, combined with some chlorine. The final step is the sanitation stage.

Eccentric-disc pumps, such as the SLS Series (pictured), from Mouvex Pumps, are designed without mechanical seals, packing, or magnets that are prone to leaks or contamination. This eccentric-disc pump replaced a circumferential piston pump that would leak a white-chocolate coating all over the floor each day. Thanks to the sealless pump, the baked-good manufacturer was able to eliminate this issue and save valuable product. Photo courtesy Mouvex.

Eccentric-disc pumps, such as the SLS Series (pictured), from Mouvex Pumps, are designed without mechanical seals, packing, or magnets that are prone to leaks or contamination. This eccentric-disc pump replaced a circumferential piston pump that would leak a white-chocolate coating all over the floor each day. Thanks to the sealless pump, the baked-good manufacturer was able to eliminate this issue and save valuable product.
Photo courtesy Mouvex.

Common maintenance issues

Experts in the industry describe four specific maintenance issues that can create havoc with food-and-beverage processing pumps.

Preprogrammed controls can be hard on CIP equipment. “Sometimes outside vendors who don’t understand this type of equipment are the ones who design the systems,” Dillon said. “For example, sometimes dead bands on tank levels in filling machines are set so tight that the motors are starting and stopping more often than they should. The pumps should be operating at varying speeds and never stopping.”

When the motor stops, it can cause backward motor operation, which can damage the mechanical seals in positive-displacement pumps. “There is much to consider, so it’s important to look at the system and how it operates and consider what you are pumping,” Dillon said. “Yogurt is more viscous than corn syrup, which is more viscous than carbonated water. Make sure the entire system is formatted to meet the needs of your product and the equipment you are using.”

Improper pump and material selection. “When a pump is not sized correctly, it can run too fast and with too much volume. This increases the wear and the cost of time and maintenance,” said Grant Gramlich, business development manager, Hygienic Americas for Dover Pump Solutions Group (PSG), Oakbrook Terrace, IL. “Improper system and piping designs on the pump inlet will cause cavitation, internal pump damage, premature wear, and failure.”

Dillon agrees this is a major issue. “One size does not fit all,” he stated. “What works well on a soft-drink-packaging line is not going to work well on a yogurt-packaging line. A standard CIP program for cleaning a positive-filtration pump will not necessarily work well for a lobe pump. Lobes need to be cleaned by hand. For progressive cavity pumps, you can only run the pump part of the time during CIP or it will shorten the life of the pump.”

Pumps running dry. “When a pump runs dry it can create wear on the seals, due to no lubrication between the seal faces,” Gramlich said. “This leads to excess heat and premature failure of the seals, which leads to downtime, and ultimately the loss of product, production, and profits.” 

Dillon agrees that no pump should ever run dry. “You need to ensure that fluid is in the line,” he stated. “A positive-displacement pump will continue to build pressure until something breaks. Pressure generates torque on the pipe and wear and tear on bearings and mechanical seals. You will pay for it in increased electric costs and maintenance.

Pump seal leaks. “In addition to affecting production, a leaking seal can create a safety hazard,” Gramlich said. “Seal leaks are also a path for contaminants to enter the pump, either by airborne exposure or from wash water from high-pressure hoses, or from external equipment cleaning of the pump-shaft seal zone.”

Gramlich recommends considering seal-less pumps in some food-and-beverage processing operations. “Seal-less technology is taking the complexity and cost out of the traditional style of pumps,” he said. “The fear of the unknown as to when the system may go down due to pump failure is virtually eliminated. It can also reduce the need for stocking additional parts, and seals can be very difficult to clean.”

Preventive-maintenance practices

When it comes to preventive maintenance, Gramlich recommends taking the first simple step of reading and understanding the operating manuals.

“Many plants have hundreds of pumps, and they are at different locations, and on different lines,” Gramlich said. “They are often forgotten pieces of equipment—until they fail. Then a production line goes down causing costly downtime. In addition to the manuals, it’s a good idea to have training videos on hand for the operators to use for training, but also during an emergency breakdown.”

Dillon and Gramlich agree that using the knowledge and expertise of channel partners is important. “The manufacturers’ distributors and service professionals know what they are doing and will come into your plant for maintenance training and product updates,” Gramlich stated. “This is part of what you pay for when you purchase the equipment, so use their expertise.”

It’s also a good idea to keep spare parts on hand in case of emergency breakdowns so the systems can be running again quickly, Gramlich said.

Case study 1: Sugar and Seals

Gramlich described a scenario in which a customer was producing a sugar-based ingredient with various colors using positive-displacement pumps with double mechanical seals and a water-flush system for the pumps.

“This is common since sugar is tacky and sticky,” Gramlich said. “Double-mechanical seals can help prevent the seal faces from gluing together when the pump is shut down after a batch or run. Double-mechanical seals are expensive since you have two per pump shaft and two shafts per pump, and they require multiple parts. Plus you have the cost and complexity of the water-flush system that must be turned on prior to pump starting and turned off after operation.”

The cost of the flush water is of great concern in today’s environment where all companies are seeking to reduce carbon footprints and save resources, he added. “The water for the flush seals is not reused. It goes down the drain and increases the sewer cost fees for the plant, so they pay for it twice,” he said. “When this plant had a seal failure, the color from the pump in which the seal failed would leak on the floor and create a mess and waste of ingredients. At initial moment of failure, the color at the leak point would squirt out of the seals as the pump shaft rotated, spraying a 360-degree stream of that color throughout the room. This contaminated the other colors, and caused more loss of production, waste of ingredients, and increased sewer and maintenance costs.”

The solution was to install a Mouvex seal-less pump. This modification eliminated the need for seal parts and the use of water for the double-mechanical seal-flush systems. “The water saving alone was enough to provide the payback on the project,” Gramlich said.  “Nobody, except the accounting department, thinks about the water bill, an often overlooked and wasted resource in facilities. Water waste is now being looked at, especially in areas such as California, that face water restrictions and higher rates.”

White-mass (plain yogurt) pumps at a major yogurt manufacturing plant are subject to a 90-minute clean-in-place (CIP) cycle after 8 hr. of operation. Each cycle involves flushing with nitric acid, sodium hydroxide, and sodium hypochlorite solutions, as well as clear water, and clear product to sanitize the operation to meet USDA, FDA, state agriculture, and local health department inspection standards. Photo courtesy SEEPEX Inc.

White-mass (plain yogurt) pumps at a major yogurt manufacturing plant are subject to a 90-minute clean-in-place (CIP) cycle after 8 hr. of operation. Each cycle involves flushing with nitric acid, sodium hydroxide, and sodium hypochlorite solutions, as well as clear water, and clear product to sanitize the operation to meet USDA, FDA, state agriculture, and local health department inspection standards. Photo courtesy SEEPEX Inc.

Case study 2: Yogurt and sterilization

“Yogurt is processed in a reactor and afterward it is sent to a sterile aseptic filling machine,” Dillon said. “This machine packages the yogurt in a totally sterile environment. The package has been sterilized. The air is sterilized. It’s like a little clean room.”

The yogurt is sent to the top of a volumetric filler. Every packaging operation has one of these, Dillon stated. “It looks like a carousel, and it works like a carousel,” he said. The piston goes up and down, and the cylinder is filled with the product. As it rotates, the piston goes down and pushes the yogurt into the cup.

“There is a tank at the top of this filling machine that is filled with yogurt, soda, cottage cheese, or whatever other food product is being processed,” Dillon said. “This tank has a level control that puts out a 4-to-20-milliamp signal and goes to a pump. As the level goes down, the pump speeds up. As the level goes up the pump slows down to try to keep the level constant in this machine. There is a detector that is basically a rod. The higher the resistance on the rod, the more it lowers. That electric signal is fed to the pump control to tell it how fast to go.”

The customer can set this level at what is called the dead band, which limits how far up and down in the tank the pump will go. “This determines the speed of the pump, and what you really want is for the pump to slow down and speed up,” Dillon said. “In this case, they set the level to be a very narrow range. The pump would go to a maximum speed very quickly and then shut off. This was tearing up everything. All the torque was causing a lot of bending and breaking. All kinds of terrible things can happen because of that high momentary load. You cannot run electric motors like that because they are rated for a certain amount of stops and starts. When this happens the production guys have set the levels, but the maintenance guys must live with the results.”

Dillon said the solution is simple—use variable-speed controls. “The VSDs will prevent the equipment from being subjected to high momentary loads and protect it from a severe reaction to the way the system was installed.”

Dillon offers simple advice when it comes to maintaining food-and-beverage process pumping systems. “In general, try to minimize the pressures,” Dillon said. “Pressure equals power, which equals wear on everything. Maximize pipe diameters and shorten the pipe runs. You pay for piping once, but you pay double for maintenance in the long run.” 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.   

205

2:00 pm
September 14, 2016
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Understand Design-Induced Pump Vibration

The system design is one cause of pump-vibration problems.

The system design is one cause of pump-vibration problems.

By Ron Eshleman, Vibration Institute

It’s no secret that many process pumps absorb massive amounts of vibration. Sooner or later, bearings, packing, or adjacent piping will fail and/or impellers will be damaged.

The five main causes of severe pump vibration include:

  • mass imbalance
  • resonance
  • piping design and installation
  • system design
  • pump design.

It should be noted that all but mass imbalance involve either facility or pump design issues. Typically, either the external-piping arrangement is inappropriate or the size of the pump doesn’t reflect the needs of the application. The following tips focus on these two issues with regard to centrifugal pumps.

randmPiping design

There are situations where a pump must fit into an awkward space, leading to an inlet condition that creates chaotic flow at the suction. Disturbances occurring at the inlet can change the direction and velocity of the flow due to piping enlargements, bends, branches, and tees. This type of situation gets the flow started through the pump at an angle that doesn’t interface well with the impeller. Such conditions produce separation-trailing vortices and turbulence, which extract energy from the flow that manifests as noise and vibration. This condition requires re-designing the inlet piping or implementing some form of flow straightening. To ensure laminar inlet flow, it’s recommended that 10 pipe diameters of straight pipe precede the pump inlet.

Pump-system design

Centrifugal pumps are designed to operate efficiently in a rather narrow flow range—recommended by the Hydraulic Institute (HI), Parsippany, NJ, as 70% to 120% of the equipment’s best efficiency point (BEP), as defined by its pump curve. Operating outside these parameters, a pump will not only be inefficient, it will excite damaging vibration. Thus, the system designer must be cognizant of the pumping requirements and make provisions if variable-flow conditions are expected. (Note: Designers must also remember that if multiple pumps will be operating in parallel, the curve and BEP will change.)

If low flow occurs due to high discharge pressure, the pumped fluid will recirculate at the suction and cause excessive vibrations. It’s not uncommon for plants to have different flow requirements during different times of the day, or to purchase oversized pumps in anticipation of future needs. Both situations fuel vibration problems.

Recirculation causes a large amount of random vibration that, in turn, may cause failures in the bearings and packing, even the impeller. Similarly, if a pump operates in the high-flow area of its curve due to low suction pressure, cavitation will occur. As cavitation bubbles pass through the pump, they explode, resulting in noise (sometimes above hearing pitch) and vibration that lead to inefficient pumping and internal pump damage.

The most practical solution for suction recirculation is to relieve the discharge pressure by rerouting some of the flow through a controlled recirculation line to the inlet. Although the pump will operate quietly, it will be doing more work than necessary—lowering its efficiency. This, however, is a reasonable approach in variable-flow applications.

An alternative, given the fact that cavitation indicates excessive flow in a pump, involves lowering the flow rate. A good way to do this is to increase the suction pressure well above the vapor pressure so that the net positive suction head (NPSHA) has a margin of 30% above the suction pressure required to avoid cavitation.

Keep in mind

Dealing with these issues may require serious redesign of systems or modification of operational modes. Remember, though, that such actions can help prevent serious damage to equipment and processes caused by vibration. MT

Ron Eshleman is technical director of the Vibration Institute, Oak Brook, IL. For more information, contact Dr. Eshleman at reshleman@vi-institute.org, or visit vi-institute.org.

310

2:03 pm
August 10, 2016
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Design Influences Rotary-Gear Pump Maintenance

Smart-sensing technology contributes to the predictive maintenance of wastewater and other facility pumps.

Pumping infrastructure represents an enormous investment for large facilities. All images courtesy of Pulsafeeder, a unit of IDEX Corp.

Pumping infrastructure represents an enormous investment for large facilities. All images courtesy of Pulsafeeder, a unit of IDEX Corp.

By Bobbie Montagno, Pulsafeeder Engineered Products

Pumping infrastructure represents an enormous investment for large processing facilities. In any given plant, thousands of pumps are needed to move liquids from point A to point B.

Some of the primary applications for which rotary-gear pumps are used in refineries and chemical-processing plants involve treating wastewater to be reused for cooling towers, boiler feeds, or to dilute chemicals that are required for other processes. For these applications, harsh chemicals such as bleaching chemicals, cleaning agents, and corrosion inhibitors are dispersed on a high-volume, continuous basis. Over time, this can take a toll on the pumping equipment, establishing the need for proper maintenance programs.      

The cost of maintenance

In most plants, annual maintenance costs for pumping infrastructure can range from 2% to 5% of the replacement value of the infrastructure. At first glance, that range seems minimal. But the delta between 2% and 5% can equal millions of dollars (or in some cases, tens of millions) throughout the life of the plant. Total maintenance costs must also be measured beyond the physical expense of the parts, the tools, and the engineers who wield them. Maintaining pumps in a chemical plant, refinery, or wastewater facility directly affects uptime, which in turn affects the bottom line.

Pumps that run regularly, feature wear items, and handle hazardous and corrosive chemicals will inevitably require maintenance. This can be a blessing and a curse.

Plant managers who get it right, in a preventive and predictive fashion, can streamline operations and maximize uptime. Those who let maintenance slip into a reactionary or “run to fail” approach can hinder operations and create ripple effects that shorten the life expectancy of equipment.

Access to the inner workings of a pump is another important design feature that affects maintenance.

Access to the inner workings of a pump is another important design feature that affects maintenance.

Predictive maintenance

Predictive maintenance requires a long-term view. It involves planning, scheduling, condition monitoring, analysis, and spare-parts management. Predictive maintenance for pumps is aided by smart-sensing technology that can alert engineers to dry-run conditions, temperature changes, increases in vibration, or decreases in pressure.

Today, sensors are readily available and their value (and deployment) will continue to expand as wireless communications connect plant infrastructure to maintenance personnel using tablets and smart phones across the Industrial Internet of Things (IIoT).

Predictive maintenance can also be done without advanced communications technology. Readily available information and historical pump performance can be used to schedule the replacement of wear parts with minimal disruption to plant operations and minimal investment in sophisticated cloud-based controls. 

Short-term reactive maintenance

Although predictive maintenance is always the goal, sometimes reactionary maintenance becomes the reality. When budgets are cut, maintenance is often considered a quick fix to address short-term financial constraints.

Reactive maintenance provides short-term savings, until equipment fails. When a failure occurs, the response relies on the skills of the on-site team and the availability of spare parts. If either fails to meet expectations, substantial losses can result from downtime and lost production.

Design impact

Maintenance starts with a simple design. Some pumps are designed for a limited life, and purchasing decisions are purely based on cost. Other pump designs seek to provide reliability over a longer life, while balancing the anticipated cost of repairs. Rotary-gear pumps are often deployed to pump harsh and aggressive chemicals, so sealless designs are easier to maintain because there is no leak point for the harsh chemicals to damage the pump or surrounding equipment.

When it comes to rotary-gear pumps, the number of spare parts should always be considered. Maintaining a sufficient inventory of gears, shafts, O-rings, and liners is critical. Spare-parts kits should contain every part that a pump requires, and kits should be easy to procure (with just a single part number). If tied to a proper design, spare parts should be simple and easy to install. Some pumps feature symmetrical parts that only fit in one way, making parts replacement mistake proof, and keeping time to repair at a minimum.

Access to the inner workings of a pump is another important design feature that affects maintenance. If the pump’s gears are not readily accessible, then engineers need to decouple the motor, close the valves, and remove piping at the suction and discharge ports of the pump. Pumps that feature a front pull-out design can be repaired in place. This minimizes downtime by eliminating the need to lock-out/tag-out the pump, and move it to the repair shop.

Maintenance ROI

Maintenance costs for a single repair will always be insignificant, compared with the costs associated with lost production and process restarts. The true return on investment associated with maintenance should be connected to a plant’s uptime. The simpler the equipment is to maintain, the faster it can be done. This gives plant operators more flexibility to schedule maintenance between shifts or whenever it is most opportunistic (or least disruptive).

Although the demographics for engineering staffs continue to change, the loss of vast experience is gradually being offset by new technology that can sense issues and alert engineers to problems before they occur. This type of sensing technology, coupled with simple designs, intuitive access, and fewer parts to maintain, forms the cornerstone of preventive-maintenance programs that keep plants up and running, and also provides management with the data it needs to make better decisions for capital budgets and long-term infrastructure improvements. RP

Bobbie Montagno is the aftermarket business line leader at Pulsafeeder Engineered Products, Rochester, NY. For the past 30 years, she has held leadership roles in application engineering, product management, and aftermarket. She can be reached at bmontagno@idexcorp.com.

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