Archive | September/October

187

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September 1, 2007
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Synthetic Lubricant Exchange

While the word synthetic often can be a negative term, implying something artificial or cheap, in lubrication, just the opposite is true. Synthetic lubricants, overall, have superior performance characteristics compared to their petroleum counterparts (see Table I). While they may be more expensive, in this case, “synthetic” means improved.

Defining synthetic lubricants In general, the synthetic designation applies to products whose basestocks have been manufactured as opposed to being extracted from naturally occurring petroleum. Synthetic lubricants are different from conventional petroleumbased oils because their molecular structures are custom designed and tailored to meet specific performance criteria.

Most petroleum-based and synthetic lubricants consist of a basestock and various additives selected to improve or supplement the lubricant’s performance. The basestock is the primary component—usually 70% to 90%—of the finished lubricant. Its structure and stability determines the flow characteristics of the oil, as well as its temperature range, volatility, lubricity and cleanliness. Since the basestock is the dominant component, one way to make a better lubricant is to start with a better basestock.

Basestock categories
The following list highlights the various types of basestocks used to formulate synthetic lubricants along with their principal applications.

  • Polyalphaolefins and dialkylated benzenes provide performance similar to mineral oils and are compatible with them. They are used as hydraulic fluids and gear, bearing lubricants and compressor lubricants.
  • Dibasic acid and polyol esters readily accept additives, which make them excellent compressor lubricants.
  • Polyglycols are used primarily for lubricating gears and bearings.
  • Phosphate esters provide fire resistance. Silicones are nontoxic, fire resistant and water repellant.

0907_interchangeability_img1

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Additives enhance basestock properties or add new ones, such as improved stability at high and low temperatures, modified flow properties and reduced wear, friction and corrosion. Basestocks and additives must be selected carefully and balanced to allow the finished lubricant to do its job—which includes protecting moving parts from wear, removing heat and dirt, preventing rust and corrosion, improving energy efficiency and extending lubricant life. Synthetic lubricants can provide economic advantages when used in place of petroleum-based lubricants. These benefits include:

  • Improved energy efficiency
  • Wider operating temperature range
  • Increased performance ratings
  • Reduced maintenance
  • Better reliability and safer performance

For best results, users should consult with the manufacturer prior to selecting synthetic lubricants. While they have outstanding performance characteristics, the proper choices must be made to ensure that the right product is chosen for any given application.

Joe Foszcz is a contributing editor to Lubrication Management & Technology. For more information, e-mail him directly: jfoz@atpnetwork.com

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201

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September 1, 2007
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Accurate, on-the-spot analysis, anywhere, anytime:Portable FT-IR Spectrometers Get Tough

Portable FT-IR Spectrometers Get Tough

2 Technologies has rolled out its new Mobility Series of Fourier Transform Infrared (FT-IR) spectrometers. Developed for use in the field, these rugged, selfcontained units are purpose-built to move FT-IR spectroscopy out of the conventional analytical laboratory and closer to the source of the sample. That means anywhere in the world.

0907_problem_solvers_img1Consisting of three systems, the MLp, the ML and the MLx, the intuitive Mobility series has been designed to survive in rugged environments and be operated with little to no training by the user. According to the manufacturer, this level of durability and simplicity of use makes these products ideal real-time process monitoring tools for lubrication condition monitoring and a variety of petrochemical, food and mining applications. With their ability to deliver accurate and precise information efficiently from even the most remote places on the planet, the three analyzers in the Mobility Series are powerful tools in the alleviation of problems associated with sample throughput and the minimization of bottlenecks.

Extending the capabilities of FT-IR technology 
Featuring an intuitive operating system and straightforward sample interface, spectrometers in the Mobility Series render traditional time-consuming sample preparation and transfer to and from a conventional lab obsolete. Users immediately obtain the type of actionable information that lets them make critical decisions on the spot. These spectrometers incorporate two new diamond-based sampling systems, one utilizing the principle of internal reflection and the other featuring a completely new type of transmission cell. Between these two systems, a broad range of liquids, solids, oils, gels and pastes can be easily and precisely analyzed.

A2 Technologies
Danbury, CT

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188

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September 1, 2007
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The Best And The Worst

ken_bannister

Ken Bannister, Contributing Editor

I recently delivered a lubrication fundamentals seminar to a group of maintainers, whose first language was not English. My opening slide depicted a 10-year-old child during the Industrial Revolution, whose job was to ensure all line shafts used to power textile mill machinery were lubricated effectively. The above Dickens quote framed the image and worked well to capture the essence of the period—or so I thought. Once I realized that the class participants were unfamiliar with Charles Dickens, A Tale of Two Cities and the Industrial Revolution, I had to explain to them my thinking behind the rhetoric and double meaning used in the slide. In doing so, I was forced to reflect on my rationale for using the slide and was surprised at just how timeless and meaningful the words and image are.

Dickens crafted his “best of times, worst of times” line—a line that became one of the most famous openings in English literature—as a way to set a tone for his portrayal of events leading up to the French Revolution. Interestingly, this historical novel was written as another important revolution was taking place—one of the greatest to date—the Industrial Revolution.

Although Dickens was alluding to the contrast between “modern” 18th century ways of life and thinking in London and Paris, and the “traditional” brutality and suppression carried out by nobility and peasants alike, his thoughts also were likely influenced by the sweeping industrial and technological changes swirling about him at the time. No wonder his words seem so profound and insightful, and that they continue to be as relevant today as when he wrote them. Take, for example, the changes occurring within our own Information Revolution.

Never before has the world witnessed such sophisticated levels of technology and communication. As a result, however, we have become so reliant on technology that we have for the most part forgotten the fundamentals, forcing ourselves into a pervasive “replace vs. repair” mentality. This approach, though, stops being a viable strategy once the technology becomes depreciated, with no more replacement parts available.

Although today’s communication is enacted at lightning speeds, the art of correspondence seems to be failing just as rapidly. While we appear to be enthralled by the amassing of vast stores of data, rarely do we take the initiative or time to turn this data into information through which true management decisions are made.

We also appear to have become so preoccupied with predicting failure that many have neglected— or have never learned—the basics of effective planning and scheduling to get the impending failure addressed prior to a catastrophic event. Likewise, cleanliness and lubrication, the cornerstones of virtually every new and existing physical asset management strategy, have never been better understood. Still, many companies today continue to neglect these most fundamental of machine care tactics.

Maybe now is the time to do things better. Let’s take a leaf out of the “lean” strategy manual. Let’s slow down the pace. Let’s really know what we are trying to achieve. Let’s build management strategies based on clear communication and the understanding of maintenance fundamentals when laying out our programs’ foundations. To borrow more words from Dickens, these from the final line of a Tale of Two Cities, “It is a far, far better thing I do… ” Today, we all can do better. Good luck!

Ken Bannister is lead partner & principal consultant for Engtech Industries, Inc. Phone: (519) 469-9173; e-mail: kbannister@engtechindustries.com

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159

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September 1, 2007
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Lubrication Management & Technology News

BEGELEY TO HEAD NEW GE ENTERPRISE SOLUTIONS 
Charlene T. Begley has been named president and CEO of GE Enterprise Solutions, a new business focused on helping GE’s global customers increase their productivity through superior information management and automation solutions. Begley has previously led GE’s Plastics, Transportation and GE Fanuc Automation units. She most recently served in a corporate role to help close the sale of GE Plastics to Saudi Basic Industries Corporation (SABIC). Begley and Jim Campbell, president and CEO of GE Consumer & Industrial, will report to GE vice chairman Lloyd Trotter through the end of 2007, when they will begin reporting to GE chairman and CEO Jeff Immelt.

GE Enterprise Solutions reportedly will have annual revenues of approximately $11.5 billion. The new business includes GE’s Equipment Services, Security, Sensing & Inspection, Multilin and Power Quality units, as well as the GE Fanuc Automation business. Enterprise Solutions also will work closely with the GE Energy Optimization and Controls business to broaden its current focus on the energy sector.

TIMKEN ANNOUNCES BIZ ALIGNMENT CHANGES 
The Timken Company has announced changes to align the organization around continued improvement in operational performance and acceleration of profitable growth. Under the new model, Timken will operate with two major business groups, the Steel Group and the Bearings and Power Transmission Group. Michael C. Arnold has been named as executive vice president and president, Bearings and Power Transmission Group. Salvatore J. Miraglia, Jr., will continue as president of the Steel Group.

Timken’s new Bearings and Power Transmission Group includes four divisions: Mobile Industries, composed of the rail, off-highway, agriculture, heavy truck and passenger car and light truck market sectors; Process Industries, which encompasses the heavy industry, power transmission and energy market sectors; Aerospace & Defense, serving the friction-management and power-transmission needs of commercial and military aviation customers through OEMs and the aerospace aftermarket; and Distribution & Services, which provides a full range of bearings, seals, grease, condition monitoring and other products and services through distributors worldwide.

On a related note, Timken also has announced the appointment of Jacqueline A. Dedo as senior vice president, Innovation and Growth. In this role, Dedo will be responsible for leading the company’s strategic initiatives to accelerate the pace of innovation and growth.

FUSS & O’NEILL PARTNERS WITH MICROMAIN CORPORATION 
MicroMain, a provider of asset and facility management software and services, and Fuss & O’Neill, a full service engineering consulting firm, have announced a new strategic partnership. Fuss & O’Neill provides services related to civil and environmental engineering, structural engineering, industrial plant services, building systems, manufacturing solutions, information technologies and design build. Headquartered in Manchester, CT, the company serves customers primarily on the East Coast. Under the terms of this new alliance, Fuss & O’Neill Technologies will integrate MicroMain™ software with other technologies including Geographic Information Systems and provide a data center for the operation of MicroMain software and other products. Fuss & O’Neill Manufacturing Solutions, which provides best practices training to maintenance organizations, will provide its services to customers using MicroMain’s computerized
maintenance management system (CMMS).

WESTMORELAND SELLS POWER OP & MAINTENANCE
Westmoreland Coal Company has closed the sale of its power operation and maintenance businesses to North American Energy Services (NAES). Included in the deal were operation and maintenance contracts for four power plants owned by Dominion Resources (Altavista, Hopewell, Southampton and Gordonville), as well as certain fixed assets of Westmoreland Technical Services. Westmoreland also has contracted with NAES to provide contract operation and maintenance services at the company’s 100%-owned ROVA power facility in North Carolina. Westmoreland previously had reported that it considers the transactions to be economically neutral. No further terms were disclosed.

MAINTENANCE TECHNOLOGY ANNOUNCES 2007 SALARY SURVEY
Just how much are you really worth in the reliability and maintenance arena? In today’s operating environments, where so much seems to be riding on so many companies being able to stay up and running at maximum capacity, Maintenance Technology is sensing that your knowledge, skills and experience probably have more value for an organization than ever before. To verify this, however, our editorial team needs to go far beyond the anecdotal and gather more concrete data regarding the actual state of the employment marketplace.

Of course, we can’t get the answers that we need without your help. That’s why we’re inviting you to participate in the 2007 Maintenance Technology Salary Survey. It’s a very simple process. Go to www.zoomerang.com/survey.zgi?p=WEB226T3XL7CSB (or the Salary Survey link on www.MT-Online.com) and answer a few basic questions about your particular role, responsibilities, etc.

Rest assured that you will not need to identify yourself. Your responses, though, along with those of others, will be compiled into a report that will be published in the December 2007 issue of Maintenance Technology. To have your input included, we ask that you complete this brief survey by October 31, 2007.

Please keep in mind that the time you take now to fill out our 2007 Salary Survey should help you and other Reliability and Maintenance Professionals on your career paths well into the future. We really look forward to your participation.

ASSOCIATION NEWS

ACEEE ANNOUNCES CHAMPIONS OF ENERGY 
The American Council for an Energy-Efficient Economy (ACEEE) has named three Champions of Energy Efficiency for 2007. Winners were selected based on demonstrated excellence in program implementation, leadership, R&D, energy policy, private sector initiatives and international initiatives. The selections were made by ACEEE’s Board of Directors from a field of 23 candidates nominated by their peers.

This year’s “Champions” include Byron Lloyd and Mark Hamann, who were honored for Industrial Leadership. Through a partnership between the Illinois Department of Commerce and Economic Opportunity (DCEO) and ComEd, Lloyd and Hamann were instrumental in enhancing the use of Envinta’s ‘One-2-Five’ software to create a holistic energy-efficiency evaluation tool. Their joint effort resulted in a new evaluation and implementation product known as the Manufacturing Energy Effi-ciency Program (MEEP).

David Zepponi also was honored for Industrial Leadership. As president of the Northwest Food Processors Association, Zepponi has implemented numerous projects to develop continued energyefficiency gains in his industry. Among these projects, he has created, populated and maintained an informative database of Best Practices that include information on system optimization, best-available commercial technologies, energy- and water-saving measures and other leading-edge energy and environment technologies.

Finally, United Technologies Corporation (UTC) was honored for Implementation & Deployment. As a diversified company with products ranging from home heating and air conditioning to aerospace and helicopters, UTC has met impressive energyefficiency goals. These include a 19% reduction in energy consumption, a 49% reduction in water consumption and a 44% reduction in air emissions from 1997-2006. As part of its latest set of environmental targets, UTC has set a goal to reduce absolute greenhouse gas emissions by 12% over the next four years and will invest $100 million toward co-generation and energy-conservation projects. To learn more about ACEEE and its Champions of Energy Efficiency, go to www.aceee.org

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4458

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September 1, 2007
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Storage Preservation Strategies

0907_equipment_reliability_img1In their quest for improved machinery reliability, many companies have rightly turned their attention to such opportunities as synthetic hydrocarbon lubricants, dry sump oil-mist lubrication and automated grease lubrication systems. To protect equipment bearings, Best-of-Class companies have taken steps to install the most advanced bearing housing protector seals. These rotating labyrinth seals are configured so as not to allow O-rings to contact the sharp edges of an O-ring groove. In some applications, Best-of-Class companies also use face-type, magnetically-closed housing seals. These are of great importance at facilities wanting to fully protect gearboxes in harsh surroundings (think: cooling tower fans), or in process plants where environmentally friendly closed-loop oil mist lubrication systems serve centrifugal pumps. All of these lube-related protective measures represent tangible, cost-justified steps in the direction of extending uptime and reducing failure risk. Nevertheless, despite the lubricant used and how a bearing housing design protects the lubricant against intrusion of external contaminants, if storage protection is ineffective—or lacking altogether—we still find dirty bearings. Frequently, dirt contamination begins with the way lubricants are transferred from storage to the equipment.

Use the right transfer method
0907_equipment_reliability_img2Studies by one of the world’s most competent and experienced bearing manufacturers, SKF, have shown the exponential decrease in bearing life due to what some—erroneously—consider “minor” contamination. All too often, this contamination comes from oil transfer containers with open spouts, missing filler caps and rust and caked-on dirt. Where dirty containers (see left portion of Fig. 1) and unacceptable work practices are still the norm, even the best lubricants and most advantageous bearing housing seals will be of no help in attaining high equipment reliability. Hence, the replacement of questionable transfer containers with rustproof, suitably proportioned and purposefully designed oil transfer tools (right portion of Fig. 1) should be a priority issue for modern industrial plants. A quick-action push-pull valve incorporated in the spout allows for the adjustment of oil flow to the particular task demanded. The lid and spout arrangement of purposefully designed containers keeps oil in, and contaminants out. It has been shown that payback periods often can be measured in days [Ref. 1].

That said, the cost-effectiveness of these lubricant containers is quite selfevident. Responsible reliability professionals consider them essential lubrication management tools. Indeed, it makes much economic sense to first ensure lube oil cleanliness before contemplating any of the other, more glamorous, high-tech approaches to optimized lubrication.

Beyond proper lubricant transfer methods, though, there also is the issue of storage adequacy that affects fitness for use of lubricated components. The first and foremost of these are rolling elements—older terminology: “anti-friction” —bearings.

Proper storage of bearings 
Spare parts protection should be among the priorities for sound asset management. Proper storage of parts—and lubrication while they are being stored—may vary depending on component and configuration. Most rolling element bearings can be stored in their original packages for several years, but the storage facility and mode of storage must be correct. There are four general requirements that must be observed:

  • The relative humidity in the storeroom should not exceed 60%.
  • The temperature should be stable within reasonable limits, although no quantitative numbers are available. Aiming for a range between 0 and 40 C (32 and 104 F) and not allowing the temperatures to fluctuate more than 10 degrees C (18 degrees F) per hour seems reasonable here.
  • Bearings must be laid down flat on the storage shelves. The loads acting on the rolling elements are now evenly distributed whereas, with “on edge” or standing storage, much of the load would act on just one or two of the bearing’s rolling elements. Moreover, the weight of the rings and rolling elements in the standing position might cause permanent deformation because the rings are relatively thin-walled. Think of an apple pie—it would not make sense to store it on edge.
  • Sealed or shielded bearings may have been pre-filled with grease whose lubricating properties are adversely affected by long-term storage. For these bearings, assume a twoyear shelf life, unless the grease (or bearing) supplier will certify a higher (or lower!) number that differs from the two-year rule. This issue then implies that reliability- focused users would refuse to purchase “surplus bearings.” More often than not, cheap surplus bearings are ones that someone else has discarded because of uncertain age, unwise storage method and unknown provenance. Since cheap surplus bearings are unsuitable for use in machines at reliability-focused facilities, they should be relegated to duties such as paperweights, doorstops and boat anchors.

0907_equipment_reliability_img3Protecting “inactive” machinery 
Machinery in storage must be protected from the elements. Painting, plating, sheltering, use of corrosion-resistant materials of construction and many other means are available to achieve the desired protection [Refs. 1, 2 & 3]. Although the protection of bearing housings is of primary importance in most fluid machines, a similar set of protection requirements applies to both “about-to-becommissioned” and “temporarily deactivated” equipment. The storage method discussed here refers to that “inactive machinery” category. The means or procedures chosen for the preservation or corrosion inhibiting of fully assembled, but inactive fluid machines will logically depend on the type of equipment, expected length of inactivity, geographic and environmental factors and the amount of time allocated to restore the equipment to service.

The basic and primary requirement of storage preservation is exclusion of water from metal parts that would form corrosion products—that means rust. These corrosion products could then find their way into bearings and seals. A secondary requirement might be the exclusion of sand or similar abrasives from close-tolerance bearing or sealing surfaces. All or any of the chosen storage preservation strategies must aim to satisfy these requirements.

Machinery preservation during pre-erection storage or long-term deactivation (mothballing) will have an effect on machinery infant mortality at the startup of a plant or process unit. Many times, machinery arrives at the plant site long before it is ready to be installed at its permanent location. Unless the equipment is properly preserved, scheduled commissioning dates may be jeopardized, or the risk of failure is greatly increased.

0907_equipment_reliability_img4Long-term storage preservation by nitrogen purging is well known in the industry. Generally, this method of excluding moisture is used for small components, such as hydraulic governors or large components, such as turbomachinery rotors kept in metal containers. Nitrogen consumption is governed by the rate of outward leakage of this inert gas and may be kept at a low, highly economical rate if the container is tightly sealed. Alternatively, the container could be furnished with an orificed vent to promote through-flow of nitrogen at very low pressure. This is called “nitrogen sweep” or “nitrogen blanketing.” Whenever the preservation of field-installed inactive pumps and their drivers is the primary objective, simply providing a moderate-cost oil mist environment will prove highly effective. Such oil mist preservation systems have contributed substantially to the flawless commissioning and operation of equipment in Best-of-Class or Best Practices plants. While it is, of course, feasible, applying a nitrogen purge will incur higher costs.

Oil mist preservation 

General setup… 

0907_equipment_reliability_img5An oil mist console like the one normally used to lubricate rotating equipment will be used to generate a preserving mist. A large and a small console are shown in Fig. 2. Since none of the equipment is rotating, a basic unit without all the supervisory alarms and back-ups often will suffice. It is recommended that air and oil heaters be used to ensure mixing effectiveness and maintaining the correct air/oil ratio. These heaters are mandatory if ambient temperatures during the period of storage drop below 50 F (10 C). Typical R&O (rust and oxidation inhibited) turbine oils (ISO Grade 32) can be used in the mist generator lube reservoir to provide oil mist at an approximate header pressure of 20″ of water column (~5 kPa).

A large oil mist console can serve hundreds of machines laid up in a temporary outdoor storage yard. One such location, often inundated by rain, is shown in Fig. 3. A storage yard in an arid part of the world will look no different (Fig. 4). A pipe header runs the length of the storage yard. Mounted along the way and at the top of the header are a number of manifolds (Fig. 5) into which reclassifiers are screwed. Plastic tubing connects the point of oil mist application at the machine to the reclassifiers. This is illustrated in Fig. 6, where plastic tubing leads to application points on a small turbine that is part of a lube oil skid. Note that even the oil reservoir is blanketed by oil mist.

It pays, however, to remember that actual on-site installed, spare or standby pumps and motors are being protected by oil mist. Oil mist both lubricates running equipment and protects non-running machines. This lubrication mode would gain even greater acceptance if these dual capabilities were being mentioned more often.

0907_equipment_reliability_img56Getting back to temporary storage, some owners have occasionally elected to construct covered temporary storage yards. Storage under cover, though, is probably more for the benefit and convenience of inspection personnel—it is neither required nor cost-justified for equipment protection. Needless to say, storage in a warehouse also is feasible. Fig. 7 depicts oil mist applied to the equipment inside a half-open crate located indoors.

Storage site preparation… A few common-sense considerations will assist in defining long-term storage measures either indoors or outdoors:

  1. Choose a site that has good drainage and is located out of the main stream of traffic. This will reduce possible mechanical damage from trucks, forklifts, cherry pickers and automobiles. A covered fenced storage area is preferred for the convenience of personnel, but it is not needed by the stored pumps, electric motors and other equipment.
  2. Position stored equipment on cribbing (pallets) if the storage site has not been paved or concreted. Arrange the equipment in an orderly fashion with access for lifting equipment.
  3. Install temporary overhead supports for the oil mist headers as per Figs. 2 and 3. Piping for the oil mist headers should be Schedule 40 screwed galvanized steel with minimum size of 1½”. All piping should be blown clean with steam prior to assembly to remove dirt and metal chips. All screwed joints are to be coated with Teflon sealant (no Teflon tape) prior to assembly to prevent oil mist leakage.
  4. Install laterals (½” min.) from top of mist header at each piece of equipment. Attach a distribution manifold to the header or to each lateral. Each distributor block typically has eight connection points in which to attach the ½” tubing. This should be sufficient to provide mist to most driver and pump combinations.

 

Pump and driver storage preparations… 
A typical connection sequence would include:

  1. Connect ½” plastic or copper tubing from distributor block to reclassifier fitting attached to pump bearing housings. (See Fig. 3).
  2. Connect ½” plastic or copper tubing from distributor block to reclassifier fittings located in pump and turbine suction flanges. If wooden, plastic or metal flanges are used, drill ½” hole through the suction flange protector to permit the insertion of the reclassifier fitting. Once reclassifier fitting and tubing are inserted in the suction flange, seal the hole with duct tape. This prevents moisture and dirt from entering the mechanical seal and wetted area of the pump by maintaining a positive pressure of oil mist. No vent holes are required because of normal leakage around flange protectors.
  3. Electric motors modified for oil mist lubrication should be stored with oil mist flowing through the smallest size reclassifier attached at each bearing cavity. Electric motor hookups are very similar to those shown in this article’s various illustrations. (Note oil mist venting from the steam turbine governor in the foreground of Fig. 3).
  4. Coat all exposed machine surfaces with an asphalt-based preservative purchased from a reputable lubricant supplier. Re-coat exposed machine surfaces every six months if needed. The preservative may be applied by either spray or brush.
  5. Rotate pump and driver shafts ¼ revolution each month to prevent brinnelling of anti-friction bearings and bowed shafts.

Oil mist generator maintenance

  1. Check weekly to ensure that air supply is dry.
  2. Refill mist generator oil reservoir weekly.
  3. Perform weekly checks of air and oil heaters on mist generator.
  4. Check oil mist header pressure daily. (Verify ~ 20″ of H2O.)

To re-emphasize 
Equipment preserved by oil mist blanketing can be stored for years with minimum maintenance and cost. The photograph in Fig. 7, dating from the early 2000s, shows the thoughtfulness and professionalism that have brought us to modern oil mist preservation. It is assumed that the internal surfaces of equipment stored in boxes and wooden crates will have been coated with a light film of preservative oil. For both indoor and outdoor storage, the various equipment-internal volumes are kept at slightly more than atmospheric (ambient) pressure. Oil mist through-flow is being achieved by providing a small vent at the bottom of the equipment casings blanketed with this oil mist environment.

Whenever possible, the equipment purchase documents should state that oil mist will be used as a long-term storage means. This might allow equipment vendors to select or predefine the most convenient oil mist inlet and vent locations.

Two final points deserve to be reemphasized:

  • Many bearings fail because unclean containers contaminate the lube oil as it is being transferred from storage drums to pump bearing housings. Reliability- focused equipment users will only use properly designed plastic containers for their lube replenishing and oil transfer tasks. Each of these containers will cost only a fraction of the cost of a single bearing failure. This is one product for which the payback has occasionally been measured in mere days.
  • Some plants make bearing procurement and storage decisions only on the basis of initial cost and schedule. This is inconsistent with a reliability focus. Proper storage and asset preservation are of great importance to plant reliability and profitability. Neglecting these issues is certain to deprive a facility of ranking among Best-of-Class producers.

References

  1. Bloch, Heinz P. & Alan Budris, Pump User’s Handbook: Life Extension, 2nd Edition, Fairmont Publishing Co., Lilburn, GA, 2006
  2. Bloch, Heinz P. & Abdus Shammim, Oil Mist Lubrication: Practical Applications, Fairmont Publishing Co., Lilburn, GA, 1998
  3. Bloch, Heinz P., Practical Lubrication for Industrial Facilities, Fairmont Publishing Co., Lilburn, GA, 2000

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284

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September 1, 2007
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Part I – Oil Cleanliness: The Key To Equipment Reliability

In today’s highly competitive global economy, equipment reliability is more critical than ever. Fluid cleanliness is key to that reliability and, ultimately, uptime. As a result, companies that recognize the importance of fluid cleanliness are more capable of delivering productivity and profits than those that ignore this issue.

Over 70% of equipment failures can be attributed to contamination. The best course of action is to minimize the introduction of contaminants. It is estimated that the cost to remove contaminants is 5 to 10 times the cost to keep them out in the first place. Thus, any World-Class lubrication program begins with good storage and handling practices and the minimization of ingressed contaminants from the environment through effective seals, desiccant breathers and other practices.

ISO Cleanliness Code 
Before cleanliness standards can be established, one has to understand how cleanliness is measured. Most common methods today measure amount and size of particles with an optical particle counter. As fluids move past a laser light, particles in the path block the light and create a shadow that is measured by a photo sensor. The sensor, which has been calibrated with a test dust, reports the number of particles by size per ml.

COPING WITH CONTAMINATION 
The three major contaminants affecting equipment are particles, water and air. This series of articles will address the area of solid contaminants and focus on proper cleanliness levels required by equipment type and proper filtration practices to achieve these targets. This month, Part I discusses cleanliness codes and basic filtration principles. Subsequent installments will cover the setting of cleanliness targets and the best way to achieve these targets, as well as proper filtration techniques and their effect on equipment reliability. Most people equate cleanliness with hydraulic systems. While it is true that hydraulics require clean oil to be effective, many other applications also require clean oil, including gearboxes, turbines, paper machine oils, rolling element bearings, etc. This series will include case histories of different components in different industries.

Dark fluids and water contamination will not give good results with an optical particle counter. With these fluids, methods such as direct counting of particles on a patch through a microscope are used. Another method for counting particles in solutions and dark liquids is pore blockage, which equates particles and size by flow decay through a sensor screen of certain size pores (like 10 micron, for example). This technique will give different results than an optical particle counter, but it can be used on certain fluids as a good trending device. (Note: Cleanliness standards discussed in this article will focus on optical particle count numbers.)

0907_contaminant_concerns_img1Prior to 2000, optical particle counters were calibrated with AC Fine Test Dust (ACFTD). Although a new calibration technique with a Medium Test Dust (MTD) that was traceable by National Institute of Standards and Technology (NIST) was established and approved in December 1999, it gave a major difference in the calibration. There is a signifi- cant difference between the two calibrations in particle size distribution as measured by an electron microscope. For example, there were significantly more particles below 10 micron with the NIST calibration versus ACFTD. In order to keep the same ISO Cleanliness Table, measured particle sizes were adjusted to reflect this difference. Previously the size ranges reported by ACFTD were ≥ 2μm, ≥ 5μm and ≥ 15μm. The new method reports ≥ 4μm[c], ≥ 6μm[c] and ≥ 14μm[c]. The letter “c” after the code indicates that the calibration was based on the NIST method. Today, most oil analysis laboratories have converted to the NIST method and use the three number designations.

Equipment cleanliness standards are established by use of ISO 4406 illustrated in Table I.

The ISO cleanliness code is reflected as a three-number designation: = 4µm[c], = 6µm[c] and = 14µm[c]. Notice that for every increase of one ISO range number the number of particles doubles. This is very significant since very small increases in the ISO range particle number can result in very large increases in the actual number of particles. Remembering one range number such as 11 (which is 10 to 20 particles) allows you to construct a table by doubling the numbers for every increase in range number. The following example on how to convert particle sizes and amounts to the three-number cleanliness designation is shown in Table II. Assume the following particle sizes and amounts were measured with an optical counter.

Let’s look at an example of how much dirt can pass through a system. Consider a fluid being pumped at 65 gpm that has an ISO cleanliness code of 22/21/18 (which is typical of new unfiltered hydraulic oil). In one year, 8800 lbs of dirt would pass through this pumping system. How long do you think a pump would last in that environment? If the fluid is cleaned to a 16/14/11 (which is the typical fluid cleanliness required in a hydraulic system), only 9 lbs of dirt would pass through the pump in one year. A six ISO code change resulted in a 1000-fold increase in particulate contamination. From this example, we can clearly see that even small changes in the ISO cleanliness rating results in large change in particulate contaminants.

0907_contaminant_concerns_img2

Filtration basics
Once the ISO cleanliness number has been established for a particular equipment type, the fluid needs to be cleaned to achieve that target through filtration. As noted in the opening sidebar, subsequent articles in this series will discuss how to set the cleanliness targets and filtration systems to achieve these targets. In the remainder of this article, however, we will be introducing basic filtration principles.

Fig. 1 illustrates the two major filter categories—surface filters and depth filters.

Surface filters are not particularly effective in systems with low-solid and large contaminants. They are usually made of woven wire or pleated paper with a consistent pore size that provides the fluid with a straight path.

Depth filters make it more difficult for a particle to pass through, thus they provides better filtration than surface filters. Depth filters incorporate cellulose, metal or glass fibers that are stacked to provide media height. Both glass and metal can have a graded (tapered) density in pore size to provide greater and more effective filter utilization. The use of finer fibers has resulted in major advances in filtration technology. Each fiber type provides different performance characteristics.

Filters can be rated either “Nominal” or “Absolute.”

  • The Nominal rating is normally used with paper filters. It is an arbitrary rating assigned by the manufacturer as to the largest particle that will pass through the filter (for example, a 10-micron nominal filter). These filters typically will only remove 50% of the particles in their size range. Since this rating is not based on actual laboratory data, it is not very useful in establishing equipment cleanliness standards.
  • The Absolute rating of a filter means that laboratory data was provided in the filter rating through the ISO 16889 Multi-Pass Filter Test shown in Fig 2. This test is used in filter development to measure the performance properties of different filters under laboratory conditions. It is used to calculate the Beta Ratio (as illustrated by Fig. 3) as follows:

0907_contaminant_concerns_img3Assume we are evaluating the filter in Fig. 3 on its ability to remove particles >10 microns and 400 particles in this size range enter the filter and two particles >10 microns pass through it.

The ISO 16889 Multi-Pass Test is conducted as follows:

  • Optical particle counters are installed both upstream and downstream of the filter to measure the number of certain sized particles entering and passing through the test filter. Circle 72 or visit www.LMTfreeinfo.com Fig. 2. The ISO 16889 Multi-Pass Filter Test (Source: HY-PRO Filtration)
  • NIST test dust is injected into a circulating fluid at an average rate of 3mg/l to 10mg/ml. Rates are varied by different filter manufacturers. A low-viscosity test fluid is circulated at 15-30 gpm.
  • All particles and their sizes are measured before and after the filter. Flow continues until the terminal pressure drop of the filter is reached, which varies by different filter manufacturers, and ranges from 60-100 psid. The terminal pressure drop is defined as when the OEM says this is the maximum drop across the filter before it is changed.
  • A Beta Ratio is calculated at every 10% of the terminal pressure drop and a weighted Beta Ratio is reported as the final result.
  • Dirt Holding Capacity, another important factor in filter performance, is calculated as the total amount of test dust the filter retained during the total run.
  • In order to better simulate actual field conditions, some filter manufacturers vary the flow rates during the test run.

Some filter manufacturers have varied the multi-pass test by varying the flow rate to more closely simulate actual hydraulic conditions. The efficiency of a filter is calculated as follows:

β – 1/β x 100

A filter with a Beta Ratio of 200 has an efficiency of 99.5%, while a filter with a Beta Ratio of 1000 has an efficiency of 99.9% This doesn’t sound like much of an increase for a five-fold increase in Beta Ratio, but with the large number of particles in most systems it can have a large effect on the ISO Cleanliness Rating.

The term today for the absolute rating of a filter refers to a Beta Ratio of at least 200 and filter manufacturers are moving to 1000. In the past, a filter was considered absolute if its Beta Ratio was 75. Today the most important factor in a filter’s performance is not its absolute rating, but how it performs in attaining a certain ISO Cleanliness Code.

Conclusion
Fluid cleanliness is vital in achieving equipment reliability and filtration is a key component in achieving cleanliness goals. Understanding basic filtration concepts is necessary in making decisions on how to achieve system cleanliness. The next article in this series will discuss setting and attaining cleanliness targets with filtration.

Acknowledgements 
The author wishes to thank Mike Boyd of Fluid Solutions and Aaron Hoeg of HY-PRO Filtration for their assistance in the preparation of this article.

Contributing editor Ray Thibault is based in Cypress (Houston), TX. An STLECertified Lubrication Specialist and Oil Monitoring Analyst, he conducts extensive training in a number of industries. E-mail: rlthibault@msn.com; or telephone: (281) 257-1526. LMT

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6:00 am
September 1, 2007
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How To Write An Effective Lubrication Procedure

0907_back_to_basics_img1The development of an effective lubrication procedure is the backbone of a successful, World-Class maintenance program. Once developed, this procedure can be expanded into the method by which all of the bearings in your unique process receive the proper lubrication.

A well-designed lubrication procedure must address three separate and distinct issues. Specifi cally, each bearing must receive the correct type of lubrication in the proper amount at the right time. If any one of these three factors is overlooked or approached incorrectly, the lubrication procedure has failed, and, as a result, the bearing will fail prematurely.

Type of lubrication…
Any Maintenance Manager worth his or her salt will be able to identify most or all of the offi cial lubricants on the plant site. Still, the authorized list of lubricants is only part of your maintenance reality. Most management-sanctioned lubricant lists contain redundant and unnecessary choices due to years of supplier and vendor recommendations combined with the preferences of your maintenance personnel. Additionally, a quick walk through the shop or lube room will, in all likelihood, lead you to discover a great deal more variety in lubricants than you thought you were using. And, if you check a few lockers and tool boxes, you will fi nd even more. Obsolete or out-of-date lubricants, unmarked oils, and unfamiliar and unapproved brands and types—if you fi nd any of these (and you will) your lubrication program is out of control.

As a general rule, the fewer lubricants it takes to sustain a manufacturing process, the better that process is. In other words, the fewer choices your millwrights and lube techs have, the fewer incorrect choices they can make.

It is important to reduce the number of lubricants to the lowest common denominator. Brand names and personal preferences do not matter. The only factors to consider in this selection are the properties of the lubricants and the specifi cations of the bearings that they are to lubricate. Ideally, you should strive to get down to two or three types of grease, one or two types of hydraulic oil, and no more than three types of other oils for your entire process. As a suggestion, have your Maintenance Planner or Reliability Engineer discuss this goal of lubricant consolidation with your lubrication vendor’s factory representatives, as well as with your bearing supplier’s fi eld engineers. Let these professionals be your experts.

0907_back_to_basics_img2Amount of lubrication…
At this moment somewhere in your mill or factory, there is a bearing running hot due to over-lubrication. Also at this moment, there is another bearing in your process running hot due to under-lubrication. Which of these conditions is worse—and which bearing will fail fi rst? The fact is that both conditions are equally as bad, since both are indications of a failed maintenance effort. Moreover, one is just as likely to occur as the other. That said, either condition will cause your process(s) to literally grind to a halt. The key to your maintenance success is to determine the maximum and minimum amounts of lubricant that you must maintain at each application, and then to design your lubrication procedures around those two fi xed points. As a fi rst step to controlling the amounts of lubrication applied to bearings, you will need to calibrate all of the grease guns in your plant. Since the lubrication procedures for bearings should be written in terms of how many shots of grease to apply, it is important to both defi ne and control how much grease is contained in a “shot.” Consistency between grease guns is the goal of calibration. It is important that all of your dispensing devices are applying the same amount of grease when your technician pulls the handle.

It also is important to thoroughly clean the guns inside and out to control contamination—and to discard any that are in poor condition. Each reconditioned and calibrated grease gun should be marked with the date before being placed back in service. You should set up a general PM in your CMMS to perform this function at least twice per year. (The calibration procedure is straightforward. For details, refer to the accompanying sidebar.)

Lubrication interval… 
It is the nature of lubricants that they use themselves up as they do their job. Thus, they must be replenished. If this replenishment occurs at the proper intervals, then the moving parts continue to move within specifi cations. But if the interval is not correct, if it is too long or not long enough, then over-lubrication or under-lubrication will be the result. Both conditions are the fi rst phases in the sequence of events that lead to machine failure.

The most accurate method available for determining lube interval is the predictive technology known as vibration analysis. If this methodology is not available or practical at your site, the OEM recommendations supplied with each bearing will be suffi cient to use as your beginning lubrication interval, provided you are not exceeding the bearing manufacturer’s specifi cations and ratings in your application.

Please note that if you are running your process in excess of its rated capacity, you will need to monitor your components with vibration analysis or thermal technology so that you can determine the point at which the component needs re-lubrication, even if you must hire an outside contractor to perform these analyses.

Developing your lube procedure 
As with any PM procedure, the lubrication procedure should be developed and written up with a specifi c machine in mind. Once you have developed the procedure for one machine, extrapolate the steps to include other machines in your process.

 

0907_back_to_basics_img3 Identify all of the lube points at the machine center. This step should be done in the fi eld by the individual who ultimately will be responsible for lubricating the machine. This individual will locate the zerks and lube points on the machineand will call them out to the Maintenance Planner, who will document the locations. Each lube point should be wiped, inspected and marked with a black or yellow paint pen so that they will be easy to locate.

 

 

0907_back_to_basics_img4 As the bearings are inspected, the Planner should make notations of any that have blown seals or that show other evidence of damage or failure. The bearings in question should be scheduled for replacement as soon as it is practical to do so. Any broken or defective grease zerks should be replaced at this time. Once the zerks have been located and cleaned, they should be covered to prevent contamination from entering the bearing or component. Push-on covers can be purchased for this purpose, or the tried-and-true method of putting a fresh daub of clean grease on the zerk can be used.

 

0907_back_to_basics_img5 Once the lube point identifi cation has been completed, compare the Planner’s notes to the machine’s drawings and manuals. The last thing that seems to be on engineers’ minds when they are designing machinery is the accessibility of lube points. Thus, it is entirely possible that there are lube points on your machine that have never received any grease at all. If this is the case, now is the time to rectify the problem. Identify any bearings that have been overlooked at this step.

 

0907_back_to_basics_img6 Bearing by bearing, calculate the manufacturer’s recommended lubrication intervals and amounts. A good tool to use when performing these computations can be found at the following web address: www.skf.com/skf/productcatalogue/jsp/calculation/ calculationIndex.jsp?&maincatalogue=1&lang=en. Be sure to convert your answer to “shots.”

 

0907_back_to_basics_img7 Bearing by bearing, write the procedure. Start at one end of the machine and take the bearings in order. Beside each bearing that you list on the lube document, leave a space for the technician’s initial, the number of shots applied and the date.

 

0907_back_to_basics_img8 Lubrication technicians must be trained in the proper methodology before being allowed to perform their work. As an introduction to their training, make them aware that the vast majority of bearing failures are the result of over-lubrication. Be certain that they are equipped with fresh grease, clean rags and a pocketful of replacement zerks when they go out into the fi eld. It is extremely important to build accountability into this training. Lubrication techs are not just grease monkeys. Their work may, in fact, be the most important maintenance function in the plant.

 

0907_back_to_basics_img9 Once you have performed your lubrication procedure, you must monitor the results. The most effi cient way to do this is with thermal technology. After the freshly-lubricated bearings have run for an hour or two, check them with a thermal camera. Any that are running hot have been over-lubed. If you determine that this condition is due to a lubrication error by your technician, retrain the individual and document the training. If you feel that the work was done as requested, then you will need to adjust the text of your lube PM accordingly.

Follow up 
As with most other maintenance functions, a lubrication PM is a living document. Each time your technicians perform such a procedure, follow up their work by checking the results. This fi nal important “step” is vital in the enhancement of your entire maintenance effort.

Ray Atkins, CPMM, CMRP, is a veteran maintenance professional with 14 years experience in the lumber industry. He is based in Rome, GA, where he spent the last five years as maintenance superintendent at Temple- Inland’s Rome Lumber facility. He can be reached at raymondlatkins@aol.com

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