Archive | Delivery Systems

181

6:23 pm
July 12, 2017
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Change Your Lubrication Mindset

Achieving desired goals requires an honest assessment of the status quo.

Oiling Gears Close-up

By Jane Alexander, Managing Editor

While physicians can diagnose health issues and recommend appropriate treatments, patients can often help themselves get better by changing some of their personal habits and/or lifestyle choices. Mike Gauthier of Trico Corp. (tricocorp.com, Pewaukee, WI) stated that the same holds true with equipment-lubrication issues. As he put it, most industrial operations “could gain a gold mine of benefits” through better management of lubricants and lubrication practices associated with critical equipment. “But only if they really want to change.”

According to Gauthier, if your plant is like countless others, with thousands of lubrication points spread out across multiple areas, the idea of changing its lubrication mindset, including simply getting started, might seem daunting. If that describes your situation, Gauthier suggests taking a graduated approach based, in large part, on an understanding of your organization’s current lubrication practices. He offers several tips for moving forward with this approach, along with sample questions from a 13-page self-assessment form that could help facilitate needed changes.

A graduated approach

“Sometimes,” Gauthier explained, “sites look at reliability programs on a scale of 1 to 10, and then fail to put a program in place because they could only hope to reach a 5.” The good news, he said, is that personnel don’t have to solve everything at once. Moreover, not every plant needs to achieve world-class status to realize a bottom-line boost in reliability.

A graduated approach can be a better option. It begins with identification of your most critical assets and the problems associated with them, establishment of key performance indicators (KPIs), and setting goals. If you can document the benefits of incremental reliability improvements, this typically creates all the buy-in necessary to get to the next level. “Start with one production line, building, or area,” Gauthier advised, “then build momentum from there.”

Before you can set reasonable goals and a plan to achieve them, however, you must fully understand your current practices. That’s why an honest self-assessment is an essential first step. To that end, Gauthier suggests taking a moment to consider your site’s current maintenance strategy. How would you characterize it?

1. (Poor) Reactive—running-to-failure and fixing things when they break down

2. (Fair) Preventive—preventing breakdowns by performing regular maintenance

3. (Good) Predictive—periodically inspecting, servicing, and cleaning assets

4. (Excellent) Proactive—predicting when equipment failure might occur

5. (Optimum) Condition Monitoring—continuously monitoring assets while in operation.

Once you’ve come to terms with the overall maintenance strategy, it’s time to dig deeper into how the site tackles lubrication. To simplify the process, Gauthier recommends going through a detailed, lubrication self-assessment exercise. Sample questions include:

1. Storage, handling, and disposal: What system best represents your current visual aid for lubricant management?

• We have adopted a color-coding system or a similar system using shapes.
• We only use one grease, one hydraulic fluid, and one gear oil. A color-coded visual-aid system is not necessary.
• No color-coding or labeling visual-aid system has been adopted.
• Not sure.

2. Lubrication and re-lubrication practices: How are equipment-oil changes determined in your facility?

• Oil changes are initiated based on oil analysis provided by a commercial partner or independent oil-analysis laboratory.
• Oil changes are initiated based on oil analysis conducted in the plant by certified lubrication technicians.
• Oil changes are performed based on a visual assessment done by our lubrication technicians.
• Oil changes are done on a calendar-based interval.
• Oil changes are done on an as-needed basis, due to a failure, a rebuild, or replacement.

3. Contamination control: What is the most common method for excluding contamination from sumps and reservoirs in your facility?

• Breather or vent originally installed by the OEM on the component.
• Normally closed, desiccating, and particulate-filtering breathers.
• No breathers of any type installed on any equipment.
• Standard, normally opened, disposable desiccant breathers.
• Standard particle filters on breather ports.
• Not sure.

4. Sampling technology: What location best describes where most oil samples are taken from your oil-lubricated equipment?

• Static oil reservoirs or sumps through the vent or fill ports.
• Turbulent zone in a representative location.
• Long runs of straight pipe.
• Downstream of system components and upstream of system filters.
• Not currently taking oil samples from any component or system at a regular frequency.

5. Lubrication-analysis program: Who is responsible for setting oil-analysis alarms and limits for the majority of your equipment?

• Not currently using oil analysis as a condition-based maintenance tool.
• Lab owned by our lubricant supplier sets all alarms and limits.
• We have not set any alarms or limits.
• We worked closely with a commercial laboratory to help define the most appropriate alarms and limits to help us achieve our reliability and production goals.

Often, according to Gauthier, the hardest part in improving management of lubricants and lubrication practices at a site is for personnel to be honest enough among themselves to acknowledge/admit to their current situation. “But if an organization is serious about changing its lubrication mindset,” he said, “this type of self-assessment will put it on the path to success.” MT

Mike Gauthier is director of Global Services for Trico Corp., Pewaukee, WI. To access the complete lubrication self-assessment described in this article, click here.

140

4:54 pm
July 12, 2017
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Move from Time- to Condition-Based Lubrication

Increasingly sophisticated machines and operations require more than legacy PM approaches.

With plant equipment and processes growing more sophisticated and demanding by the day, so must everything that keeps them up and running, including approaches to machinery lubrication. Integrated, proactive-maintenance technologies and strategies are key for fast-paced industrial operations that want to be competitive, and are easily justified in economic terms.

With plant equipment and processes growing more sophisticated and demanding by the day, so must everything that keeps them up and running, including approaches to machinery lubrication. Integrated, proactive-maintenance technologies and strategies are key for fast-paced industrial operations that want to be competitive, and are easily justified in economic terms.

By Ken Bannister, MEch Eng (UK), CMRP, MLE, Contributing Editor

The term “time-based maintenance” is well understood in industrial operations. The premise is simple. A regular maintenance/lubrication event is scheduled on the basis of a calendar anniversary, i.e., weekly, monthly, quarterly, yearly, or other interval, or on a machine’s run-time clock, i.e., 100, 250, 1,000 hr., or some other specified number of hours. Foundational to legacy preventive-maintenance (PM) programs, this type of event scheduling has served industry well for decades.

Plant equipment systems and processes, however, are becoming more complex and demanding by the day. In turn, they are requiring increasingly sophisticated maintenance approaches. Going forward, if they haven’t already done so, sites will need to adapt to an integrated, proactive-maintenance approach that maximizes machine availability and reliability. The economic justification is simple.

In a legacy time-based event, a forced machine downtime is usually scheduled to perform maintenance or lubrication, e.g., oil change. Older equipment designs usually dictate that a machine must be shut down and locked out to determine its status and conduct scheduled activities in a safe manner. This method obviously has an impact on an operation’s throughput capability.

Given today’s fast-paced operating environments, a forced two-hour downtime to change oil on a calendar schedule—whether it needs to be changed or not—is no longer acceptable. We still need to change oil, but we need to treat that oil as we would any asset and maintain it over an extended lifecycle. That means changing it only when conditions warrant change. This type of monitoring strategy reduces machine intervention and increases production throughput, as well as reduces costs related to the purchasing, handling, and disposal of lubricants at a site. It also fits perfectly in any corporate asset lifecycle or sustainability initiative.

Moving from a time-based to a condition-based lubrication program is an ideal change-management vehicle for transforming and improving an operation’s state of lubrication. Successful design and implementation of a condition-based lubrication program can manifest itself in different forms, depending on a plant’s industry sector and current state of lubrication. Several “conditional” strategies can help your site gear up for this move with little effort and expense.

Implementing conditional strategies

Two basic elements underpin a condition-based lubrication program. The first speaks to the integrated, proactive-maintenance approach through involvement of operators as the primary “eyes and ears” in performing daily machine condition checks. The second element assures consistency and accuracy in the execution of value-based condition checks and lubrication actions.

Some maintenance personnel might argue that the old PM job tasks stating “Fill reservoir as necessary” or “Lubricate as necessary” are perfect condition-based instructions. Not so fast: Those instructions, unfortunately, rely solely on maintainer experience. They will not deliver consistency and accuracy without controls that dictate how we assess a machine’s condition and take appropriate actions built into the “necessary” part of the work-task equation. That’s where implementation of the following conditional strategies pays off.

Strategy 1: Reservoir-fill condition

If a lubrication system is to deliver peak performance, it will require an engineered amount of lubricant. In re-circulating and total-loss systems alike, designated minimum and maximum fill amounts aren’t always clearly indicated on the reservoirs. In such cases, the first step is to ensure that a viewable sight gauge is in use, complete with hi-lo markers for manual checks.

For critical equipment, an advanced approach can utilize a programmable level control to electronically indicate the fill state to operators and maintenance personnel. Some equipment, of course, is designed with reservoirs inside the operating envelope that require machine shutdown to perform checks or fill up. These systems can be inexpensively redesigned with remote “quick-connect” fill-lines piped to the machine perimeter that will allow the reservoirs to be filled to correct levels while the machine runs. (For additional tips, see this article’s “Learn More” box at the bottom of this article.)

Strategy 2: Oil condition

When the term “condition-based” is used, oil analysis often comes to mind. The first stage in controlling the oil’s condition is to ensure the product is put in the reservoir at the correct service-level of cleanliness and that a contamination-control program is in place. This will require a number of things: an effective oil-receiving and -distribution strategy, operators and maintainers working together to keep the lubrication system clean, use of desiccant-style breathers, and remote, “quick connect” fill ports that can be hooked up to filter carts outside of a machine’s operating envelope. (For additional tips, see the “Learn More” box at the bottom of this article.)

The second stage is to monitor the oil’s condition for contamination, oxidation, and additive depletion through the use of oil analysis. Extracting oil samples for testing purposes is predominantly a manual process that can be conducted outside of a machine’s operating envelope through a remote-piped “live” re-circulating line or by using a remote-piped sight-level gauge with a built-in extraction port.

Based on a condition report, the machine’s oil can be cleaned by using a filter cart, with no downtime, or replaced at a conveniently scheduled time. An advanced alternative is to use an inline sensor to monitor and electronically indicate pre-set oil cleanliness and water-presence alarm levels. (For additional tips, see the “Learn More” box at the bottom of this article.)

Oil-temperature condition is important wherever ambient temperatures fluctuate and an oil might become too viscous to be pumped through a system. This situation can create a bearing-starvation effect. In environments where this could happen, a thermostat-controlled automotive block heater or battery blanket heater can be incorporated in the system to ensure lubricant usability and machine uptime.

Strategy 3: Machine condition

The ultimate lubrication-control is based on equipment running condition. Effectively lubricated machinery will require less power to operate and bearing life will be extended by as much as three times that of ineffectively lubricated machines. Correctly engineered and set up, automated, centralized lubrication-delivery systems ensure the right amount of lubricant is applied in the right place, at the right time. If your plant’s equipment is predominantly manually lubricated, investigate converting to automated systems that require less maintenance and return their investment in weeks or months. (For additional tips, see the “Learn More” box at the bottom of this article.)

Automated systems are highly adaptable to new IIoT (Industrial Internet of Things) protocols. The capability now exists to install bearing-heat sensors (that set temperature ranges of different bearings) for monitoring, amperage metering (needed because friction demands an increase in motive power that translates through amperage draw), and sensing of oil levels and cleanliness.

Condition signals can be sent to an automated system’s lubricator to turn on and off for a timed or actuation cycle, or to indicate an alarm state. These conditions can be monitored with software tools and used for computer-based automated decision making to reset a lubricator program based solely (and precisely) on condition needs of a machine within its ambient operating environment.

Remember this

Condition-based lubrication respects and treats the oils that a site relies on as integrated assets in equipment and process uptime. The condition-based approach is an excellent first step for a site that wants to shift its focus from legacy PM approaches to integrated, proactive-maintenance strategies. Regardless of industry sector, this type of maintenance is what plants of today and tomorrow require to be competitive. MT

Condition-based lubrication and system design are among the topics covered in contributing editor Ken Bannister’s 2016 book, Practical Lubrication for Industrial Facilities–3rd edition (Fairmont Press, Lilburn, GA), co-written with Heinz Bloch. Contact Bannister at kbannister@engtechindustries.com, or 519-469-9173.


learnmore2“All Sight-Level Gauges Aren’t Created Equal”

“Control and Avoid Lubricant Contamination”

“Put Portable Filter Carts to Work”

“Implement an Oil-Analysis Program”

“Practical Oil Analysis: Why and What For?”

“Tune Your Lubrication-Delivery System”

214

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.

338

8:39 pm
April 12, 2017
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Specify the Right Lube-Delivery Line

Fig. 1. Cost should not be a factor in your lubrication-delivery-line choices. While the steel-tubing in this progressive-divider-lubrication system block took more time to install than plastic lines, the additional, but small, up-front cost will pay long-term dividends, especially if leaks or blockages occur.

Fig. 1. Cost should not be a factor in your lubrication-delivery-line choices. While the steel-tubing in this progressive-divider-lubrication system block took more time to install than plastic lines, the additional, but small, up-front cost will pay long-term dividends, especially if leaks or blockages occur.

The wrong lubrication-delivery line can compromise the reliability of your production equipment.

By Ken Bannister, MEch Eng (UK), CMRP, MLE, Contributing Editor

During lubrication-training workshops, I ask participants to name the components that make up a centralized lubrication system. Most will answer in the context of an automated-delivery system by citing the pump, reservoir, metering devices, and pump controller. Rarely do they actually include the lube-delivery lines in their answers.

Lubrication-delivery lines are important and integral components within centralized lubrication systems—be they state-of-the-art automated designs or simple, manual arrangements. Specifying the wrong type can put machinery reliability at risk.

The function of a lubrication-delivery line is straightforward: It must connect a bearing point to a lubricant source (indirectly from a meter or gang block, or directly from the pump) and allow the lubricant to be contained within the line to flow without constriction. As lube-delivery systems are hydraulic in nature, the line must also be capable of withstanding pressures ranging from hundreds to, in some cases, many thousand of pounds-per-square-inch (psi) of pressure.

Listen to the latest in a series of monthly lubrication-related podcasts with Ken Bannister. This edition of the podcast focuses on lubrication-delivery line matters.

Line size and material

Correct choice of size and material is essential if a lubricant-delivery line is to provide reliable service. For the most part, the line plays a passive role within a centralized system and is typically fixed to the side of a machine (the exception being where a lubricated part moves independently of a piece of fixed machinery, in which case, the line is used to provide the flexible connection.) Before a delivery line can be specified, however, a number of basic questions regarding the overall lube-system design must be answered, including:

Fig. 2. The bundled plastic tubing in this progressive-divider system are difficult to individually trace from pump to the lube block. These types of lubrication-delivery lines are also difficult to physically attach to a machine’s frame and, consequently, more vulnerable to damage.

Fig. 2.
The bundled plastic tubing in this progressive-divider system are difficult to individually trace from pump to the lube block. These types of lubrication-delivery lines are also difficult to physically attach to a machine’s frame and, consequently, more vulnerable to damage.

Is this system automated or manual? The answer is crucial in assessing line material, diameter, and wall thickness, which relate specifically to the line’s material-burst pressure rating.

• Manual systems designed to “gang” grease nipples in a central block can be lubricated by grease guns capable of developing as much as 15,000 psi.

• Manual hand pumps and automated systems operate at much lower pressures (between 100 and 2,000 psi).

What type of automated/engineered delivery system is specified? Some system designs require a single line size throughout, whereas others require a main and secondary line of different diameters and flow rates. For example:

• Single-line-resistance and pump-to-point systems are low-pressure systems designed to deliver the total amount of lubricant in one pump cycle. In such systems, i.e., total-loss, single-size-diameter delivery lines are sufficient.

• Single-line positive-displacement-injector, dual-line-injector, and progressive-divider systems require multiple cycles of the pump connected to a larger diameter main line used to rapidly fill the injectors/main distribution blocks, and smaller-diameter secondary lines that connect the metering outlets to the lubrication points,

• Re-circulating-oil systems usually require single-size-diameter delivery lines and a larger-diameter, return-line system.   

How many lubrication points are included in the system and where are they located on the machine? This question is required to map out a central pump location and injector or delivery block locations so the line distances can be measured for material take-off amounts, and in the case of long line lengths, to calculate pressure drop so the correct line diameter(s) can be calculated.

What lubricant type and grade/viscosity are you planning to use? The fact that grease requires higher pressure than oil to move through blocks and lines will affect the choice of line material type and diameter.

Fig. 3. If single-chamfered compression fittings designed for nylon lines are mistakenly used on steel lubrication-delivery lines that require double-chamfered fittings, seals can be compromised, causing leaks at the fittings. (Courtesy Bijur Delimon International, Morrisville, NC, bijurdelimon.com.)

Fig. 3. If single-chamfered compression fittings designed for nylon lines are mistakenly used on steel lubrication-delivery lines that require double-chamfered fittings, seals can be compromised, causing leaks at the fittings. (Courtesy Bijur Delimon International, Morrisville, NC, bijurdelimon.com.)

In what type of working environment will the system be used? Ambient and working temperatures can affect line integrity. Furthermore, if unprotected, copper, brass, and plastic lines can be easily damaged in high traffic areas—especially where lift trucks are used regularly.

What is your budget? Cost should not be a factor in line choice. Figures 1 and 2 show progressive-divider blocks, one piped in correctly rated plastic tubing and the other in steel. While steel tubing (Fig. 1) takes considerably longer to install, the additional, but small, up-front cost can pay long-term dividends, especially when a problem, such as a leak or a blocked line, occurs. The plastic tubing (Fig. 2) is bundled together. making it difficult to individually trace a line from the pump to the lube block. In addition, these lines are difficult to physically attach to the machine frame and, consequently, more vulnerable to damage.

Although the steel lines used in Fig. 1 are dirty, they all have line-ID (identification) tags that make them easy to trace and troubleshoot. The steel-line system also looks more engineered and permanent in comparison with the bundled-plastic-line example.

Once you’ve gone through these six questions, present the answers to your lube-system designer or manufacturer/supplier. These resources can help you determine the best line material for a specific application.

Main problem causes

Problems in lubrication-delivery lines manifest as leaks or blockages. A leaking line will starve lubricant from one or many bearing points and seriously affect the associated production equipment’s reliability. Leaks are invariably found at connection points and line-bend areas. Keep the following in mind:

• Copper lines are very soft and can easily work-harden at bend points if significant machine vibration occurs.

• Nylon lines can be easily over-tightened or not cut square at the connection points. This can cause a leak at the compression fitting.

• If a single-chamfered compression fitting designed for nylon lines is mistakenly used on a steel line, which require a double-chamfered compression fittings (see Fig. 3), they can be compromised, causing a leak at the fitting.

• To reduce cost, nylon lines can be used as a substitute for flexible-hose lines in moving-bearing-point applications found on, among other things, machine slides and rams. Plastic lines, in most cases, are not rated for cyclic repetitive-movement duty.

Blockages in lubrication lines usually occur when they’re pinch-damaged from being hit by a foreign object that crimps or flattens the line shut. This situation causes a line backpressure that can blow the fitting or eventually stall an entire progressive-divider system, starving many bearings in the process. Steel lines offer the best defense against pinched lines.

Best practices

To ensure no bearing is starved after a lubrication-system implementation or line replacement, always pre-fill the lubricant line with the correct grease lubricant before final fastening to the bearing. Or, in the case of oil, operate the lube system and open all bearing points to ensure oil is flowing at each point before final tightening.

Finally, never forget that lubrication-delivery lines are a matter of choice. Reliable lube systems, in turn, depend on making the correct choice. MT

Contributing editor Ken Bannister is co-author, with Heinz Bloch, of the book Practical Lubrication for Industrial Facilities, 3rd Edition (The Fairmont Press, Lilburn, GA). As managing partner and principal consultant for Engtech Industries Inc. (Innerkip, Ontario), he specializes in the implementation of lubrication-effectiveness reviews to ISO 55001 standards, asset-management systems, and training. Contact him at kbannister@engtechindustries.com, or telephone 519-469-9173.

1476

3:23 pm
January 4, 2017
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Understand Motor and Gearbox Lubrication

1701flube01opto

Over-lubricated bearings will produce excess heat through internal fluid friction that can easily be detected with an infrared camera. Photo: Fluke Corp.

Among other factors, motor and gearbox lubrication programs require understanding and a controlled lubrication approach.

By Ken Bannister, MEch Eng (UK)CMRP, MLE, Contributing Editor

When a driven component is required to operate at a speed different than that of the attached motor (driver), a designer can choose from two basic power-takeoff speed-reduction/increaser methods. The first uses pulleys or sprockets of different diameters mounted to the motor and driven shaft, with power transmitted by a connective belt or chain. The second design connects the motor to the driven component through a gearbox, with the motor connected to the gearbox input shaft and the driven device connected to its output shaft.

When viewed in a maintenance-management-system database for lubrication purposes, belt/chain-drive motors and motor/gearbox units are rarely handled with separate PM work orders. Rather, the lubrication requirements are integrated as line items on a much broader machine PM work order. This is fine for sub-fractional and smaller horsepower motors. Larger, more expensive (and re-buildable), motors—usually 20 hp and more (there is no set rule to this)—require treatment as a separate entity from the parent machine, with their own asset numbers and PM/lubrication regimes, so as to compile work-history files. Furthermore, in the case of  motor/gearbox combinations there are two specific entities, one electro-mechanical (motor), the other purely mechanical (gearbox), that are best treated individually when assessing and managing lubrication needs.

Assuring motor and gearbox reliability is the result of good alignment practices and, more importantly, effective lubrication practices.

Bannister on Lubrication

Accompanying this article is the first of a new series of monthly lubrication podcasts with Ken Bannister. This month, he provides additional information about factors involved in lubricating motors and gearboxes.

Motor lubrication

Motors are electro-mechanical devices that turn electrical energy into mechanical energy. Motor magnets and windings are wound on and around a central shaft. This shaft is simply supported by two or more rolling-element bearings at each end of the motor frame and housing. These bearings are the only lubrication points on a motor, and are virtually always grease lubricated. With rare exception, fractional- and small-horsepower motors use sealed bearings and make no provision for external bearing lubrication. If the motor is balanced, aligned, and not overloaded, it should deliver a long life with no additional lubrication. This is not usually the case with larger motors, which are often subjected to heavier and often more variable loads, requiring larger bearings.

Depending on the motor design and manufacturer, external grease fittings usually are installed on motors rated at 5 hp and become much more prevalent on 20-hp units. When motors become more powerful and heavier, they place more load on the bearing points, therefore requiring grease replenishment on a more-frequent basis.

If a motor is to operate at peak efficiency, its bearing cavities (the available space between the balls, raceways, cage, and seals) need only be filled to 30% to 50% capacity, at any time. Because the bearings are hidden behind end plates, they are lubricated “blind” and are often subject to overfilling—especially with manual greasing. When this happens, the grease has nowhere to go except through the bearing cavity into the winding! Grease-filled windings lead to premature failure and a rapid decrease in motor energy efficiency, evident by the rise in motor’s amperage draw.

To alleviate this condition, larger motors are designed with a drain-plug or screw in the end cases that, once opened, will allow excess grease to flow through the bearing and out of the motor end case. If this is kept closed during the greasing process, excess grease will channel directly into the motor windings. If your motor has a grease fitting but no drain plug, use extreme caution not to over-lubricate, as the excess will make its way into the winding.

Over-lubricated bearings will produce excess heat through internal fluid friction that can easily be detected with an infrared camera. This can also be achieved by adding contaminated grease with a dirty grease nozzle or through cross contamination with a non-compatible grease.

Grease-gun inconsistency can be ironed out through use of a single-point auto lube (SPL) setup to deliver a small amount of lube on a continuous basis for as long as a year, depending on the size of bearing and lube reservoir.

SPL manufacturers have setup guidelines based on bearing size and altitude (atmospheric pressure is relational to constant-pressure grease flow) for initial setup, which can then be fine-tuned by monitoring amperage draw and/or bearing temperature. These signatures will be unique to each motor and will differ based on size and load.

Gearbox lubrication

Gearboxes are self-contained mechanical devices that allow power to be transmitted from an input shaft to an output shaft at different speeds through the meshing of different-sized gear sets held on each shaft. The gears and shafts are supported on bearings contained within a sealed “box” that also serves as a reservoir for the lubricating oil. Gearbox dimensions can range from palm-sized to room-sized. With few exceptions, all are oil lubricated.

Depending on the style and size, gearboxes employ a number of methods to move the lubricant over the gears and bearings, the most popular being:

• Splash lubrication. This is a common gearbox-lubrication method in which the reservoir is filled part way with lubricating oil to ensure partial coverage of all the lower mating gears. At speed, these gears use surface tension on their teeth to “pick up” lubricant and transfer to other gears and bearings through meshing and by “flinging and splashing” the lubricant in all directions within the sealed reservoir.

• Pressure lubrication. This method is frequently found on mid- to large-sized gearbox assemblies that use a gear-driven pump, typically located inside the gearbox, to work in conjunction with the “splash” method. Pressure-lubrication systems draw lubricant from the reservoir through a pickup-filter screen and pump oil at pressure through an internal piping system to bearings and gears that would be difficult to service with splash lubrication.

• Mist, or atomized, lubrication. This approach, reserved for the largest of gearboxes, uses a vane-style pump that picks up lubricant from the reservoir and “slings” it at a plate, causing it to atomize into a micro-drop mist. The mist saturates all of the mechanical components within the sealed gearbox.

In all three lubrication methods, choosing the correct oil viscosity and additive package is most important. Typical to all gearboxes is the need to ensure:

No cross-contamination of lubricants occurs during oil top-ups or change-outs. Label your gearbox with the correct oil specification.

No dirt or water contamination is allowed into the gearbox.

The drain, fill, and breather caps are always tightly in place.

The gearbox is regularly wiped clean of dirt and debris that will act as a thermal blanket and unnecessarily heat up the oil.

The gearbox is not over-filled creating churning (foaming) of the oil that can rapidly deplete the anti-foam additive, causing the oil to oxidize. This requires attaching low- and high-level markers to the gearbox sight gage.

If you have all of the above practices in check, make enquiries regarding the use of synthetic gear oils. These not only last longer but can cut your energy consumption as much as 4%. MT

Ken Bannister is co-author, with Heinz Bloch, of the recently released book Practical Lubrication for Industrial Facilities, 3rd Edition (The Fairmont Press, Lilburn, GA). As managing partner and principal consultant for EngTech Industries Inc. (Innerkip, Ontario), he specializes in the implementation of lubrication-effectiveness reviews to ISO 55001 standards, asset-management systems, and training. Contact him directly at kbannister@engtechindustries.com, or telephone 519-469-9173.


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Tune Your Lube-Delivery System

This mechanically actuated grease pump uses a pitman-arm control connected to a large-diameter rotating-machine shaft. The shaft attachment point is offset from the center to produce a reciprocating arm motion that produces a rocking motion at the pump shaft. This emulates the back-and-forth motion of the manual lever arm. Photo: EngTech Industries Inc.

This mechanically actuated grease pump uses a pitman-arm control connected to a large-diameter rotating-machine shaft. The shaft attachment point is offset from the center to produce a reciprocating arm motion that produces a rocking motion at the pump shaft. This emulates the back-and-forth motion of the manual lever arm. Photo: EngTech Industries Inc.

Optimizing a lubricant-delivery system is not difficult and the benefits are significant.

By Ken Bannister, MEch Eng (UK), CMRP, MLE, Contributing Editor

When a piece of rotating machinery is purchased, it almost always is delivered with a designed lubrication system or approach in place. The type of equipment can be as complex as a high-end, integrated, computer-controlled, automatic lubricant-delivery system that supplies each bearing point with a measured amount of lubricant based on time, cycle, or condition.

Or, if a site’s budget was tight during the initial specification and procurement process, its new machinery could arrive with a more modest form of lubrication technology involving inexpensive grease nipples and/or oiling points at each bearing point and the simplest of instructions in the operations and maintenance manual to “lubricate as necessary with a specified lubricant.”

Those examples represent the extremes in lubrication design and approach. Fortunately, from one extreme to the other and in between, maintenance-department personnel have the ability to tune lubrication-system setups to improve/optimize their particular lube-program deliverables. It’s not as daunting a task as it might seem.

Lubricant-delivery systems are typically designed with one or more areas of adjustability to allow tuning. Take advantage of this capability. Depending on the design mechanics of the system, tuning adjustability can be found in three major places: the metering devices, the pump, and the pump-control system.

Metering devices

Adjustable metering devices, such as those found in single-line, positive-displacement, injector (PDI) systems (oil or grease); dual-line injector systems (oil or grease); or pump-to-point box-cam systems (oil only) allow plant personnel to change the amount of lubricant charge that’s delivered to specified lubrication points. These types of systems are less expensive to design, as they require little or no initial design engineering and put the injector-calibration setup responsibility squarely on the user. The downside to this scenario is that it can easily lead to over- or under-lubrication if the user isn’t familiar with the equipment or doesn’t understand how to calculate a bearing’s lubricant requirements. Maintainers and machine operators can also tinker with settings at will if they feel a bearing requires more or less lubricant—a situation that doesn’t merely change the dynamic from adjustability to “tamperability.” It, too, can lead to over- or under-lubrication and, ultimately, premature bearing failure.

Tuning such systems necessitates calculating the hourly bearing requirement and determining the minimum-to-maximum lubricant output shot per cycle for each injector size/type. The accumulated total amount of lubricant is what must be pumped through the delivery system every hour, and the system must be set up accordingly. From this point on, with all injectors calibrated, any further adjustment is to be carried out at the pump.

Protecting these systems from tampering calls for controlled access. This can be accomplished in numerous ways, the simplest of which is “ganging” multiple injectors together, building a key-access lock-box around them, and allowing access only to designated lubrication or reliability personnel.

NOTE: Popular single-line-resistance and progressive-divider metering devices are non-adjustable. They depend on upfront engineering by the system supplier (incorporated in the cost of the system), before delivery to the machine builder or end user. Their setup adjustability is through pump-output calibration. 

Lubrication pumps, controllers

Lubrication pumps, which come in many configurations and sizes, can be powered manually, electrically, or pneumatically. The delivery rate for all of these can be adjusted on the pump itself or through a pump controller.

Manual pumps are mechanically actuated with a lever arm connected to a positive-displacement piston. The output delivery can be adjusted by restricting the length of the piston stroke with an adjustment at the lever cam. Lubricant is manually drawn into a single-acting piston chamber by moving the lever arm in a back-and-forth arc motion. The lubricant is then moved out of the pump through an internal check valve to the distribution lines and on to the metering devices. The pump is returned through opposite action on the lever or by a return spring.

If reciprocating or rotary machine motion is available, the lever arm of the manual pump can be replaced with a power-takeoff pitman-arm linkage attached to the motion device. The photo on the previous page shows a series-progressive distribution system with a mechanical pump attached to a pitman arm that’s connected to a large-diameter rotating-machine shaft. The shaft attachment point is offset from the center to produce a reciprocating (up and down) arm motion that produces a rocking motion at the pump shaft. This emulates the back-and-forth motion of the manual lever arm.

By changing the length relationship of the pitman-arm attachment point and arm, the degree of arc will change and speed up or slow down the number of pump strokes per hour. As evidenced by the surplus grease around the bearing in the photo, the pump setting is incorrect and needs to be recalibrated to reduce the amount of lubricant delivery.

Pneumatically or electrically powered lube pumps are sized according to the system output requirement per hour. For effective lubrication, smaller amounts of lubricant, delivered on a frequent basis, e.g., every 10, 15, or 20 min., are preferable to a large amount that’s delivered hourly. This approach allows the designer to use a smaller, less expensive output pump and control and provide the ability to adjust total delivery through the number of actuations or lubrication cycles per hour. Setup is accomplished through programming (adjusting) the on/off timer that controls power to the pump.

Pump-lubrication cycles can be controlled in other ways, including through counters that calculate the number of machine or production operations, or by a condition signal, such as an amperage-draw meter that indicates an increase in energy draw from the machine-system motor (due to a rise in mechanical friction that’s most often caused by lack of lubrication). This popular control mechanism is used in automotive-assembly plants to measure the amperage of conveyor-drive and take-up motors that activate and deactivate conveyor chain and pin lubricators.

In simple, modestly priced, manual-grease systems, a grease-gun acts as the pump and metering device, while control is regulated by the grease-gun user and the scheduled preventive-maintenance (PM) instruction. Optimization and setup involves a two-step process in which the grease-gun’s displacement must be determined to first ascertain the number of shots required to meet the bearings’ calculated needs and, second, the frequency of application that must be controlled by the PM schedule. The number of grease-gun shots or the PM schedule is used to fine tune any increase or decrease in the lubrication amount or frequency.

Keep in mind

Automated lubricant-delivery systems are much more accurate, consistent, and easier to set up and control than manual systems. As a result, bearings run cooler (due to less friction), require less energy, and have as much as three times the service life of their manually lubricated counterparts. In short, return on investment from the relatively small purchase and implementation cost of an automated system is quickly realized. 

Regardless of its design, a lubrication-delivery system should be evaluated on a bi-annual basis to assess its effectiveness. Those evaluations should include reviews of bearing-failure incidents, grease usage, changes in bearing running temperatures and energy draw, as well as checks for physical signs of over-lubrication and system neglect. As with the initial setup of these systems, a little adjustment later on—make that a little fact-based, correct adjustment—can pay enormous dividends. MT

Ken Bannister is co-author, with Heinz Bloch, of  Practical Lubrication for Industrial Facilities, 3rd Edition” (The Fairmont Press, Lilburn, GA). As managing partner and principal consultant for EngTech Industries, Innerkip, Ontario, he specializes in the implementation of lubrication-effectiveness reviews to ISO 55001 standards, asset-management systems, and training. Contact him at kbannister@engtechindustries.com, or telephone 519-469-9173.


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Battery-Driven Grease Gun

1607mtprod20pTLGB 20 battery-driven grease gun has an integrated grease meter to dispense the proper amount of lubricant for an application. A rechargeable 20-V lithium battery delivers extended service life. A built-in light illuminates the work area. The gun dispenses as many as 15 grease cartridges/battery charge and has two flow rates adjustable for specific application. Pressures to 10,000 psi can be achieved.

SKF USA Inc.
Lansdale, PA
skfusa.com

63

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

Screen Shot 2016-07-05 at 10.29.06 AM
Grand Terrace, CA-based EnviroGear Pump (part of PSG, a Dover company) PSG Group, has announced the release of  G Series models G1-82, G1-133 and G1-222 (3-in, 4-in., and 6-in.) metal-sealed internal gear pumps.

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

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

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

For more information, CLICK HERE.

 

 

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