Archive | Reliability & Maintenance Center

78

6:11 pm
May 15, 2017
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Slurry-Pump Tips: Extend Mechanical Seal Life

Selecting the right pump with the right type of mechanical seal is the first step toward slurry-pumping success. (Photo copyright ITT Goulds Pumps)

Selecting the right pump with the right type of mechanical seal is the first step toward slurry-pumping success. (Photo copyright ITT Goulds Pumps)

Although you may consider mechanical seals to be relatively small components in slurry-pumping systems, they can be the crucial bridge between failure and success. An incorrect or poor seal selection can cause major damage to the pumping system. The bottom line: If your operation wants to get the most from its slurry pumps, the choice of mechanical seals is crucial. Fluid-handling experts at Crane Engineering (Kimberly, WI, craneengineering.net) offer several tips for extending the life of these components.

— Jane Alexander, Managing Editor

Seal Considerations

As discussed in a recent blog post on craneengineering.net, increasing slurry-pump reliability starts with an understanding of the challenges involved in moving highly abrasive fluids such as manure, cement, and starch. These pumps clearly have their work cut out for them. Thus, when selecting a mechanical seal for slurry service, pay attention to these details:

randmRobust design characteristics. Heavy slurry usually involves a high solid content. A seal design that can withstand erosive impacts while protecting the seal faces is a must. Specially designed seals for slurry applications typically feature durable construction materials, hardened faces, and heavy-duty springs to ensure the seal faces have the correct pressure setting to seal the system.

Restriction bushings. When pumping a slurry mixture, process pressure will naturally drive the particle-filled fluid into the sealing interface, causing abrasion and accelerated wear. A restriction bushing isolates the mechanical seal from the harsh process so that the seal is mostly sealing the cleaner, cooler flush fluid.

Proper flushing. A proper flushing plan will keep abrasives away from the seal faces. Seal flushing also keeps things moving in the stuffing box to prevent solids stagnation and build-up. As with any pumping application, you should always avoid dry running conditions.

Additional Considerations

Choosing the proper seal for a slurry pump is just part of the equation. It’s also imperative to select the right pump for the job and to maintain it properly.

As with other pumping systems, poor equipment conditions caused by bad bearings, cavitation, excessive impeller loads, and misaligned shafts can lead to excessive vibration and shock to the mechanical seal. A slurry pump running under these conditions will generate more heat and more opportunity for abrasives to enter the sealing interface. MT

Lubricating Film Matters

According to Crane Engineering’s fluid-handling experts, regardless of your pumping application, a lubricating film at the sealing interface is always needed.

A film that is too thick will increase leakage and may allow particulate between the mechanical seal faces, increasing wear from abrasion. Conversely, a film that is too thin will generate heat and degrade materials. Keeping the sealing interface cool and clean will promote longer seal life.

Crane Engineering is a distributor of industrial-grade pumps, valves, filters, wastewater-treatment equipment, and other fluid-processing technology. Services include repair, corrosion-resistant coatings, and skid-system design and fabrication. For more information and instructional videos, visit craneengineering.net.

131

6:01 pm
May 15, 2017
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Use IR Switchgear Windows Properly

IR windows provide a measure of safety and reduce labor by allowing thermographers to inspect switchgear without opening panel covers. (Photo courtesy of Fluke Corp.)

IR windows provide a measure of safety and reduce labor by allowing thermographers to inspect switchgear without opening panel covers. (Photo courtesy of Fluke Corp.)

By Jim Seffrin, Director, Infraspection Institute

In an effort to reduce the risk of injuries associated with arc flash, many sites have installed infrared (IR) transmissive windows or ports that permit IR inspections of switchgear without the need to open panel covers. Although such devices can provide a measure of safety and help to reduce labor associated with those inspections, they pose unique challenges not associated with direct line-of-sight imaging.

Switchgear windows are typically constructed of a rigid frame with a fixed IR transparent material that enables an imager to view through them. Switchgear ports consist of a rigid frame with small openings through which an imager may be sighted. Depending upon type, some feature a single hole, others incorporate metal screens containing multiple holes.

randmIR windows will always attenuate infrared energy received by the imager. While this attenuation affects qualitative and quantitative data, the greatest challenge involves temperature measurement. Accurate temperature measurements can’t be obtained through a screened port. Furthermore, the ability to accurately measure temperatures through an IR window is possible only if the following conditions are met.

• The window opening must be larger than the imager’s lens objective.
• The target must be at or beyond the imager’s minimum focus distance.
• Values for window transmittance and target emittance must be known and properly entered into the imager’s computer.
• The imager’s lens must be kept perpendicular to and in contact with the window.

When it is not possible to meet all of the above conditions, imagery should be evaluated only for its qualitative value. As always, any inexplicable hot or cold exceptions should be investigated for cause and appropriate corrective action taken. MT

Words to the Wise: Beware Hidden Electrical Danger

Getting ready for an infrared inspection of electrical equipment often requires manual preparation of switchgear components, which could be a riskier endeavor than many people might think. Unwary thermographers and other personnel can, in fact, be injured through contact with cabinets or component surfaces that have become accidentally or unintentionally energized.

Switchgear enclosures and components are generally designed to prevent their surfaces from becoming energized. Under certain circumstances, however, enclosures and other dielectric surfaces can become unintentionally energized to significant voltage levels. This potentially lethal condition can be caused by improper wiring, faulty equipment, or contamination due to dirt or moisture.

When conducting infrared inspections on or near electrical equipment, always keep the following in mind:

• Only qualified persons should be allowed near energized equipment.
• Treat all devices and enclosures as though they are energized.
• Never touch enclosures or devices without proper PPE (personal protective equipment).
• Do not lean on or use electrical enclosures as work surfaces.
• Always follow appropriate safety rules.
• Know what to do in case of an accident.

Working alone near exposed, energized electrical equipment isn’t just dangerous, it’s a violation of federal law. Thermographers who perform infrared inspections on any electrical equipment should never work alone. Since CPR can’t be self-administered, at least two people trained in first aid and CPR must always be present when working near most exposed, energized equipment. Having a second CPR-trained person along not only satisfies OSHA requirements, it may save your life.

To paraphrase a time-honored electrician’s admonishment, remember that while there are old thermographers and bold thermographers, there are no old, bold ones.

Jim Seffrin, a practicing thermographer with more than 30 years of experience in the field, was appointed to the position of Director of Infraspection Institute (Burlington, NJ), in 2000. This article is based on several of his “Tip of the Week” posts on IRINFO.org. For more information on electrical systems, safety, and other infrared-related issues, as well as various upcoming training and certification opportunities, email jim@infraspection.com or visit infraspection.com.

41

5:48 pm
May 15, 2017
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Get Your Cybersecurity Off the Ground

Hacker HackerangriffImplementing cybersecurity defenses for industrial-control systems can seem intimidating. The right initial actions are crucial. Alexandre Peixoto, cybersecurity expert for the DeltaV distributed-control system from Emerson (Round Rock, TX, emerson.com), urges users to look closely at these seven key areas. They can offer a good defense-in-depth strategy in the short term:

• Workstation hardening: Ensure that the workstation configuration meets security policies.
• User-account management: Maintain unique user accounts and password-change routines.
• Patch/security management: Keep hardware and software up to date.
• Physical security/perimeter protection: Limit physical and electronic access to system networks.
• Security monitoring/risk assessment: Develop security policies and system-monitoring behavior.
• Data management: Develop guidelines for secure data creation, transmission, storage, and destruction.
• Network security: Ensure that system networks are properly segregated and protected.

For organizations wanting to get new cybersecurity programs off the ground fast, Peixoto recommends starting with the first three items on this list. Inexpensive to implement, they typically can be completed in-house.

—Jane Alexander, Managing Editor

randmWorkstation hardening

Workstations are usually the entry points to isolated networks. New installations run at peak security but, over time, changes intended for temporary use, such as a remote access or use of removable media, are not reversed. These changes increase the system’s attack surface, especially if the allowed remote connections aren’t monitored or periodically audited.

Cybersecurity isn’t a set-and-forget type of initiative. Operations should monitor and maintain all workstations using the initial configuration as a baseline. System administrators should keep records of their system’s security policies and develop policy guidelines surrounding what can and cannot be changed.

Dedicated applications are available to help audit essential files and services running on each control-system workstation. These applications can be valuable tools in assessing cyber-threats within an industrial control-system environment.

User-account management

Individual user accounts with appropriate permissions should be part of every organization’s security policy. Properly assigning user permissions also has a strong impact on cybersecurity. While it may seem easier to give every user high privilege access to the system, this approach increases the impact of a cyberattack, no matter which account is stolen. Developing and applying guidelines for user accounts is the first step, but setting a strategy for account management, based on those guidelines, is key to long-term control-system cybersecurity support.

Strict enforcement of password complexity and change routines will make it harder for unauthorized users to gain access using stolen passwords or brute-force attacks. A best practice is for each user to have a unique username and password for the control system that is distinct from those they use on enterprise business systems.

Patch/security management

Properly maintaining a control system means keeping hardware and software up to date. When a system is unpatched or outdated, the organization is exposed to cyberattacks.

Organizations need to keep track of operating system updates, antivirus updates, and software hotfixes that are available for their systems and regularly apply these patches. Unpatched systems are vulnerable to cyberattacks that are based on known vulnerabilities. Appropriate, timely patch management can be accomplished internally or by using support programs available from automation-system vendors.

Bottom line

Not only is it easy to overlook cybersecurity, it’s difficult for plants to justify allocating resources for it if they’ve never been attacked (or have been, but don’t know it). Unfortunately, when security vulnerabilities are exploited, the costs required to recover a system are high and the impact widespread.

Focusing on the right first steps today can help secure your industrial-control system and develop an internal cybersecurity posture in your organization. MT

For more information on cybersecurity, go to emerson.com/cybersecuritymanagement.

179

8:01 pm
April 13, 2017
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Listen Up: Stop Lube-Related Bearing Failures

Ultrasound technology can help reduce bearing and equipment failures associated with improper lubrication procedures.

Ultrasound technology can help reduce bearing and equipment failures associated with improper lubrication procedures.

Regardless of industry sector, lubrication methods are crucial to plant reliability and maintenance efforts. Consider the fact that lube-related failures account for 60% to 80% of premature bearing failures. While lack of lubrication and use of the wrong lubricant for an application have been cited as major causes of such failures, over- and under-lubrication are also harmful. Preventing those last two scenarios is one area where ultrasound technology can play an important role.

— Jane Alexander, Managing Editor

According to UE Systems (Elmsford, NY), by using an ultrasound instrument to listen to a bearing while applying lubricant and then monitor, i.e., watch, the decibel level, a technician can determine when adequate grease has been applied and, just as important, the threshold at which over-lubrication begins.

In short, when bearings aren’t lubricated properly, friction can cause damage and threaten processes. Ultrasound equipment can read the decibel levels of over- and under-lubricated bearings and indicate to maintenance personnel if adjustments are in order. Consistent dB levels let a technician know that the level of lubrication is where it should be.

Experts at UE Systems describe three tiers of acceptable lubrication practices and where ultrasound technology fits into them.

randmGood practice

The baseline lubrication practice is to follow the bearing manufacturer’s recommendations to determine the exact amount of lubrication necessary based on bearing size, speed, and type, and rely on runtime and operating conditions to develop a lubrication schedule. While “good” is a starting place, there is room to improve.

Better practice

The next level uses ultrasound equipment for more exact lubrication procedures. These tools tell maintenance technicians when to stop lubricating a bearing, rather than hoping the schedule is accurate and guessing at bearing condition. Ultrasound can also inform technicians if there are other problems with the bearing, unrelated to lubrication.

Best practice

A best lubrication practice is to combine a frequency schedule and ultrasound tools with data collection and trend analysis. By examining the history of lubrication with dB levels and other sound files, maintenance technicians can begin to predict when bearings may be approaching failure and take preemptive action. Alarm levels can be set to alert technicians when lubrication is approaching dangerously low levels.

The best ultrasound programs allow easy integration of data analysis with probes, listening devices, and lubrication tools. MT

How Ultrasound Technology Works

Air- and structure-borne ultrasound is high-frequency sound that human ears can’t hear. These high-frequency sounds travel through the air or by way of a solid. The ultrasound instrument senses and listens for the high-frequency sound, and then translates it into an audible sound that is heard through the inspector’s headset. The unit of measurement for sound is a decibel (dB) level, which is indicated on the display of the ultrasonic instrument.

Ultrasound can be used in conjunction with (and is supportive of) vibration analysis and other predictive-maintenance approaches. In addition to mechanical inspections of rotating equipment and associated condition-based lubrication programs, applications for ultrasound include detection of compressed air and gas leaks; inspection of energized electrical equipment to detect corona, tracking, and arcing; and inspection of steam traps.

For more ultrasound information and to download a printable infographic on “3 Ways to Incorporate Ultrasound in Lubrication Testing,” visit uesystems.com.

105

7:53 pm
April 13, 2017
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Prevent Cable Failure in Dynamic-Cable Tracks

Paying attention to these details can help you reduce the risk of unexpected and costly downtime.

Paying attention to these details can help you reduce the risk of unexpected and costly downtime.

Cable failure within a dynamic-cable track can lead to costly, yet, in most cases, easily avoided, downtime. David Smith of U.S. Tsubaki Power Transmission LLC (Wheeling, IL) points to several important considerations for maximizing the performance life of cables running through your plant’s power-transmission-equipment systems.

— Jane Alexander, Managing Editor

Proper cable selection

Incorrect cable designs are often installed in a dynamic-cable track. Given the high rates of motion and speed under which cable tracks perform, be sure to select and install a cable specifically designed to operate in your particular environment or application.

Proper cable-track sizing

To achieve maximum life from your cables, assure ample amounts of free space within the cable track. At a minimum, cables should have 10% free space around them, with a maximum fill rate within the cable track not to exceed 60%. As the speed and cycle rates of a cable track increase, the cables must have adequate space to operate properly.

It is also imperative for the cable track to have the proper bend radius. Dynamic cables are generally designed to operate with a bend radius that’s greater than 7.5 times the outside diameter of the cable. A tighter radius will reduce the performance life of your cables.

randmStrain relief

Every cable requires effective strain relief as it enters and exits the cable track. This strain relief ensures that proper cable length remains within the track as it cycles back and forth. Insufficient strain relief is one of the most commonly overlooked considerations during cable installation.

Proper strain relief often can be accomplished by simply zip-tying the cables to the strain-relief fingers that have been molded into the cable-track brackets.

Internal vertical dividers

Another often-overlooked consideration involves the use of internal dividers within the cable track. Vertical dividers between the cables ensure that each cable is confined to its proper location and spacing within the track and is unable to cross over or “tangle,” with the other cables. Keeping your cables in proper alignment will help extend their performance.

Cable-carrier material selection

Even with proper strain relief, relative motion between the cables and cable carrier crossbars can result in some scuffing of the cable jackets. By selecting a crossbar design/material that best interacts with the cable jacket material, you can reduce or eliminate that scuffing.

For example, a nylon cable track with aluminum crossbars is much friendlier to the PVC jackets of most electrical cables than a standard glass-fiber nylon cross bar. MT

David Smith is director of sales for the Milwaukee-based KabelSchlepp Division of U.S. Tsubaki Power Transmission LLC. For more information on dynamic-cable tracks and other power-transmission topics, visit ustsubaki.com.

148

7:42 pm
April 13, 2017
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Top Tips For Maintaining Air Compressors

Use these tips to improve air-compressor performance and increase uptime.

Use these tips to improve air-compressor performance and increase uptime.

Air compressors and their output are valuable assets on which countless plants depend for efficient daily operations. Regular attention to and proper management of the health of these critical equipment systems can save time and money in all manufacturing systems.

John Skalka, service manager for Sullair (Chicago) offers several tips for maintaining your site’s air compressors. According to Skalka, following these procedures to help monitor and maintain air-compressor performance can result in reliable equipment and reduced downtime.

—Jane Alexander, Managing Editor

Maintain filters and separators.

Proper maintenance of a compressor’s consumable filters and separator elements will not only help to ensure maximum unit uptime, but also maximize its efficiency and performance.

Air intake and oil-filter maintenance should be conducted every 2,000 hr. Monitor the oil filter for contamination and wear metals, leading indicators that air-end maintenance is required.

Air/oil separator elements should be changed every 8,000 hr., along with compressor fluid. Proper air/oil separator maintenance will ensure oil carryover stays within the manufacturer’s specifications.

Remember that use of OEM service parts and lubricants in compressor maintenance will help ensure optimal equipment performance.

randmSample oil.

Regularly acquiring and analyzing oil samples helps monitor the condition of the compressor lubricant, as well as the unit itself. A robust oil-sampling and monitoring program will alert the user to fluid degradation resulting from increased viscosity, ingestion of chemicals or particulate, and high water content. It can also identify the presence of wear metals, which is a sign of bearing degradation, prior to catastrophic failure.

Oil-condition monitoring makes it possible to change the lubricant only when necessary to maintain peak performance. Samples should be drawn quarterly, during routine service maintenance on a compressor.

Remember to always draw your samples through a clean oil-sample port or from the center of the oil sump. Doing so will ensure that the results are free from particulate contamination.

Keep variable-speed drives clean.

Many of today’s compressors are equipped with a variable-speed drive (VSD) that increases efficiency and reduces energy consumption. While VSDs are electrical components, they are not completely maintenance free.

Most VSDs contain cooling fans and heat sinks that can accumulate dust and dirt during regular operation. Maintenance activities will help them run cooler and prolong their service life.

Eliminate the guesswork.

For plants that are unable to ensure regular compressor maintenance with in-house resources, outside support is available. Check with your local air-compressor sales and service center about plans that allow skilled, factory-trained technicians to routinely service your compressor(s) and related air-system equipment.

Finally, keep in mind that proper maintenance will help you realize years of reliable service from your compressor. MT

Sullair, part of Accudyne Industries (Luxembourg and Dallas, accudyneindustries.com) has been developing and manufacturing air compressors since 1965. For more information, visit sullair.com.

150

7:33 pm
April 13, 2017
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Develop a ‘Profitable’ Reliability Strategy

Maximizing operational profitability requires maintenance and operations to approach reliability, efficiency, and profitability from a common strategic plane.

Maximizing operational profitability requires maintenance and operations to approach reliability, efficiency, and profitability from a common strategic plane.

Automation systems have primarily been focused on using real-time control to improve the efficiency of industrial operations. But, as process- and logic-control technology and techniques have advanced over the years, control strategies have improved significantly. As a result, plant assets are being pushed harder than ever before—something that’s had an understandably negative impact on their performance and reliability.

The effect of all of this, said Peter G. Martin, Ph.D., of Schneider Electric, Foxboro, MA, is that companies are now paying much more attention to and driving advancements in plant maintenance. Over the past two decades, traditional responsive maintenance has evolved to include preventive, predictive, and prescriptive strategies. According to Martin, while the results have been promising, some in the industry are beginning to realize that improving business performance requires maintenance and operations strategies that collaborate much more than they now do.

“If the ultimate objective is for both maintenance and operations to maximize operational profitability,” Martin wrote, “approaching reliability, efficiency, and profitability from a common strategic plane is essential. This collaborative approach is referred to as profitable reliability.”

randmDeveloping a profitable reliability strategy might seem daunting, but some fairly simple steps can help move industrial operations in the right direction. Martin outlines them here:

• Identify the critical equipment assets that represent the largest opportunity for performance improvement. Those units will frequently be found among your rotating equipment, since mechanical movement tends to wear them out over time.

• Determine what process and condition measurements are required to perform a complete asset-performance analysis. At the base equipment level, this can be a relatively simple exercise. The goal is to measure the maintained state of the equipment (how it is operating compared with its optimal operating condition) and the probability of failure over a specified time.

• Install the appropriate measurement on the asset. Typical process measurements, along with condition measurements, provide substantial reliability information. For example, the amount of process output based on a given energy input might decline as the asset nears failure.

• Use the process and condition measurements to calculate the asset’s maintained state and its probability of failure.

• Use the process and condition measurements, in conjunction with business data, to determine how much the asset contributes to real-time operational profitability. The goal is to maximize that profitability over a given time.

• Determine how much operational (control) freedom each asset has. For example, is the only operating action to turn the asset on and off or is it possible to operate the asset at a less-than-maximum level?

• Develop an asset-control scheme that includes integrated reliability and process-control strategies that maximize operational profitability. These strategies might include reducing the output of the asset to extend its time to failure so you can finish a run or a contract.

• Move the reliability measurement and control up to the next-level asset set (for example, the process unit) and perform the same control-strategy analysis. This analysis should be simpler to perform once the base equipment level assets are under control.

• Continue this process all the way up the asset hierarchy, until you have real-time control strategies in place for all your critical assets and asset sets. This would include process areas, plants, and even enterprises. MT

—Jane Alexander, Managing Editor

Peter G. Martin, Ph.D., is vice president, Marketing and Innovation, for Schneider Electric’s Process Automation business. For more information, visit Schneider-electric.com/processautomation.

241

3:16 pm
March 13, 2017
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‘Lean’ Your Way To Workplace Efficiency

03175srandmThe 5S process has proven to be a highly effective organizational tool for modern, Lean work environments. Are your operation’s plant-floor personnel taking full advantage of this methodology?

According to experts in storage, organization, and material-handling solutions at Akron, OH-based Akro-Mils (akro-mils.com), organizations that invest in a 5S process increase productivity, create higher-quality products, and lower operating costs through simple waste removal, visual identification, and efficient use of space. By incorporating a 5S Lean methodology, they note, facilities can:

• improve workflow and productivity
• develop a cleaner, more efficient environment
• create extra workspace
• increase safety
• reduce wasted time and effort
• boost worker morale
• ensure improvements remain intact.

A recent Akro-Mils blog post provided the following refresher on steps in the 5S process, along with some ways this Lean approach can lead to improved workplace efficiency.

— Jane Alexander, Managing Editor

randm1. Sort.

The first step in the 5S Lean methodology is eliminating items that are not needed for the current workflow. This step is crucial to reducing clutter, eliminating outdated or expired materials and supplies, and freeing up valuable real estate in your workspace. A key decision point in this step is determining which items stay and which items go. Unnecessary items are moved out of the workspace and either immediately disposed of or stored offsite and dealt with later.

2. Set in Order.

Frequently used workstation materials and tools should be arranged so that all needed items are readily accessible and easy to find. In this step, the workspace is reorganized and redefined for the most efficient use of space. All tools and supplies are labeled and organized, and a system is implemented to make sure they are always returned to their proper locations.

3. Shine.

When first implementing a 5S Lean process, all work areas receive a thorough cleaning and inspection. A formal cleaning and maintenance schedule is then developed to prevent dirt from accumulating and keep equipment in proper working condition.

4. Standardize.

Benchmarking and evaluation tactics should be used in your 5S Lean process to maintain a consistent approach for carrying out tasks and procedures. For example, standardizing the storage of supplies through color-coding is an effective way to provide helpful, easily recognizable visual indicators throughout an entire facility.

5. Sustain.

The last step is to continue maintaining efficient workflow and productivity with your 5S Lean system. The best way to do that is through education and empowerment of those using the system. Communicating the benefits of an ongoing 5S process will help ensure personnel’s continued adherence to it and, just as important, that there is no falling back into bad habits. Equipping workers with a well-designed 5S checklist does more than merely support the following of those procedures. It’s an effective way to create accountability and keep this valuable process going strong. MT

For more information on 5S and other workplace topics, and to download a copy of the Akro-Mils 5S Procedure Checklist, visit akro-mils.com.

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