Bearings vs. Lubricants_ Regreasing
Commenting to Ana Maria Delgado CRL with LUDECA, about the bearings and the lubricants that keep them operating, it occurs to me to write about a point of view that few people observe.
Simon is a condition monitoring specialist from a local oil refinery. He contacted SDT for advice on predicting flexible coupling failures. Currently, they perform condition monitoring on their pumps and motors using vibration analysis. They identified most bearing failures in time but could not detect coupling defects; there was no safe place to mount a contact sensor. Several unexpected failures caused shaft damage and unplanned downtime.
Within the facility they identified 58 pump systems considered “A Critical”, meaning if they go down, the plant goes down. I suggested ultrasound as a fast, safe, and affordable coupling monitoring solution. The model I recommended not only provided Simon with a means to observe couplings, it also measures vibration, eliminating the need to carry two data collectors.
Vibration analysis performs poorly on flexible couplings for two reasons. First, there is no suitable contact point for an accelerometer. Second, the primary defect symptoms of a defective coupling are friction and impacting. These are best detected with ultrasound. An airborne sensor placed near the coupling quickly detects problems. If necessary, Simon can capture a dynamic measurement and trend the defect as it worsens. The SDT270DU gives Simon two choices. He can periodically check for defects (Good) or Simon can integrate all 58 couplings into his established bearing routes (Best).
I explained to Simon how several clients already trend couplings using the Flexible Wand. The SDT270 collects a STATIC ultrasound measurement that gives four indicators of condition. The first two – Overall RMS and Max RMS – indicate the level of friction produced by the defect. When these indicators rise, maintenance may consider corrective alignment during a planned shutdown. The second two – Peak and Crest Factor – identify the emergence of impacting. Together, all four indicators establish a lifecycle trend for each coupling.
Once impacting appears, the Peak indicator increases in step with Overall RMS. Since Crest Factor (CF) is a ratio between RMS and Peak, a rising CF indicates that the window for simple maintenance has narrowed. At this stage inspectors collect a DYNAMIC measurement. The DYNAMIC measurement gives a visual representation of friction and impacting severity using the time view. For both STATIC and DYNAMIC measurements, it’s important to define the signal acquisition time.
User defined signal acquisition time, available exclusively on SDT instruments, is a luxury that lends ultrasound technicians the highest level of precision. Without the ability to set the sample time, inspectors must guess when to pull the measurement trigger, and then question the validity of their data. Simon explained that all 58 pumps turn at speeds above 1800 RPM. Accordingly, he should set his SDT270’s signal acquisition time to between one and three seconds. This guarantees data samples over 30-90 shaft revolutions.
Shaft couplings are guarded for safety and ultrasound inspectors working around rotating equipment must follow company safety policies. SDT designs safety considerations into their solutions. The Flexible Wand’s 10mm diameter sensor allows access to couplings without the need to remove safety guards. The 21” long sensor sports a comfortable, ergonomic grip that keeps inspector’s hands at a safe distance.
Simon seemed convinced but wanted to #HearMore. Since this solution was already working well at a nearby paper mill, I introduced Simon to the plant manager, Sunil, and invited them both to lunch. Sunil and Simon connected on many common reliability issues that afternoon. He confirmed the affordability of this solution based on coupling failures alone but went on to explain how their mill was rolling out ultrasound for acoustic lubrication, steam trap monitoring, electrical inspection, and air leak management. Simon and Sunil continued their conversation well into the afternoon. They agreed that ultrasound, with its 8 applications pillars for reliability, represented a fast, safe, and affordable technology with the potential to revolutionize reliability culture. I sat back, happily watching two passionate specialists strategize about reliability culture. I love my job.
by Diana Pereda
Repost from Benchmark PDM Maad Blog
Let us review this case study on a common issue when working on a pump and motor alignment done by Brian Franks, Owner and Field Service Technician of JetTech Mechanical.
He begins in the normal manner entering the distances of the machine. As you can see this is not a small machine (see Figure 1 below) – there are 57 inches between the motor’s feet and if you add all the measurements together you have 87 inches from the Stationary laser detector unit and the back foot of the movable machine (motor). Notice also that it is a spacer coupling.
He continues doing the alignment work by taking a soft foot measurement on each of the machines and as you can see, there is very little, so we know it’s a stable base that the machine units are sitting on.
An important note is that they would need the coupling open/loose and the pipe disconnected in order to do this correctly.
The new ANSI standard (ANSI/ASA S2.75-2017/Part 1) allowable soft foot tolerance is two thousandths (0.002 thou or 2.0 mils) of shaft deflection and he is below this, so he is good to go. He documents it for his report.
He now performs the machines’ shaft to shaft alignment.
Notice that he’s removed most of the bolts from the coupling in order to allow the coupling to flex. This is a stiff coupling so you don’t want it locking up during the alignment and you also want to make as few moves as possible. So, this is a good practice. This also tells me they know what they are doing which is good.
The tool they are using is an Easy-Laser XT770 which is a dot laser system that can read in the horizontal and vertical plane.
by Diana Pereda
Commenting to Ana Maria Delgado CRL with LUDECA, about the bearings and the lubricants that keep them operating, it occurs to me to write about a point of view that few people observe.
When we talk about lubricants, and regularly when referring to bearings, we talk about grease. Where the grease really performs its work, is at the point of contact of the ball or roller and the inner or outer race. The rest of the grease in the bearing housing does not perform lubricant work. The problems begin when we have to re-grease it, the regreasing of bearings is very particular, the type of grease, the correct amount, at the right time. This is something we hear in lubrication training, particularly on the way to World Class Lubrication. However, when you know the tools of Lean Six Sigma, you are always looking for the True Root Cause.
But at some point we have thought about the bearing housing, where the grease enters the housing, what is the route to the bearing, and more importantly where the grease residues damaged by time and temperature leave, not counting current discharges in the case of electric motors. In that passage, it is important that the grease that enters displaces the grease inside the cavity, that the grease that enters pushes the grease that is between the ball and the track, thereby relieving the bearing load. Not being less important that the grease that has finished its useful life goes outside, it does not lead to the winding in the case of electric motors.
If we stop to think about the cavities of the bearings, there are many readings about it, but a writing from Heinz P. Bloch P.E. comes to mind, for a Pump Symposium in 2015, “Lubrication Delivery Advances For Pumps and Motors Drivers”, One of the best writings on the topic of bearing lubrication, thanks to H. P. Bloch, I recommend you read it. This paper puts you to think about the importance of the passage of grease through the bearing and how it has to be allowed to evacuate the grease that has ended its useful life inside the bearing housing.
Of all types of bearing housing, only the one that allows cross-flow of grease when lubricating is ideal. When add grease to a bearing the grease under hydraulic pressure of the gun will move through all possible cavities, but if we give a relief on the opposite face of the bearing where the grease entry is, then it will do its job, to remove the spent grease and accommodate the new grease between the ball and the inner and outer race, extending the useful life of the bearing, avoiding maintenance interventions, improving productivity.
Reading the letter of Mr. Heinz P. Bloch, reminds of an old friend his beginnings in the industry, when he just graduated from college, he was in probation and have to go through the different facets of Manufacturing, and then Maintenance, he had to work directly with an industrial mechanic, who did not like to teach, therefore he had to learn by looking, without asking questions, he forced it, “which he thank him ”, to look at all the details in the mechanical assets, how many threads the screws have, the size of the pipe, if the bearings were balls or rollers, where the grease enters the bearings in the electrical motors, the right tool for the job, etc.
He forced him to speak the language of the bearings, to touch them carefully and capture the operating temperature, to make contact with the nail and appreciate the vibration, to listen and smell the condition of a rotating asset, it is interesting.
The grease has to come into contact with the ball and the track, if the Bearing Housing does not allow the new grease to displace the old grease and come into contact with the ball and the track, the bearing will fail, it will be long term but the fatality will occur, or you will have unwanted mechanical interventions of rotating assets. The training of technicians who perform the lubrication task is very important, for them to understand this.
by Diana Pereda
Our colleges at Benchmark PDM recently had a request from a customer to do some pump alignment. When we normally think about pump alignment, we usually think of shaft to shaft alignment. In this case, they wanted bore alignment. They were installing a brand-new pump and when they rotated the shaft, they could hear grinding.
After further inspection one of the techs could see that the bearing housing had been moved – either during shipment or when it was stored. They could see that the dowel pin had been damaged.
If you pop the lid off this style of pump (See Figure 1 – photo courtesy of KSB Pumps Canada), we see the shaft and the center mounted impeller. On each side of the impeller we have the wear rings, which sit in the bores. Outside of that we have two stuffing boxes or seal bores and outside of these we have the bearing Journals which are also bores. All of these bore centers need to be colinear, meaning in a straight line.
The old traditional methods for doing this type of work was done using piano wire or a mandrel. They would use the stuffing box or the wearing bores as reference points then measure to see if the bearing bores where in alignment. This method was “hit and miss” because its so difficult to set up and measure in this way. It also took a very long time.
Using a laser-based measurement system has significantly reduced the time taken to do bore alignment. More importantly, it has improved the accuracy significantly. There are now automatic reports that go with the final bore alignment that has been completed – a documented history of the work is very important.
There are many different applications where bore alignment is done using lasers. For example, extruder barrels that need to be aligned to a gearbox in the plastic industry, crankshaft bearing journal bores in diesel/natural gas engines or compressors in the oil & gas and energy industries and stern tube alignment in the shipping industry. These are just three examples that show how varied the type of alignment work is.
by Diana Pereda
I’m sure you have heard how important precision maintenance is to the health of your equipment, but have you ever seen the real impact it has? Recently, to show this point within my company, we did some training to demonstrate how restoring a machine into a precision state can make a real difference.
We divided a training class into five groups. Each group focused on bearing installation, alignment, fastener torquing, balancing, belt alignment and other precision maintenance practices on machinery. The chart shows the impact of precision maintenance and why it is so important. Notice how the vibration, temperature and amperage was reduced as each machine was brought into a precision operating state.
Red values are the as-found measurements for each machine/group and green is the as-left condition after the precision maintenance activities were completed. These were not large machines, but this clearly shows how taking a little extra time and care with equipment will reduce the operational stresses, reduce wear and failure conditions, save energy and improve reliability.
Often we focus much of our time on defect identification, planning, scheduling and elimination (repair) of equipment defects. These practices must be executed properly. However, we tend to overlook the importance of restoring and keeping our equipment in a precision operating state so defects are not created in the first place.
Visit LUDECA Learning Center where you can download procedures for Precision Alignment, Bearing Installation, and Balancing.
by Diana Pereda
by Diana Pereda
When you are working with nature, you treat it with respect. And that’s what this dam facility on the Kootenay River in British Columbia does (image, above left). When you harness the power of a river you need your control systems to work. The spillway gates control the level of the dam and in this example, it is lifted and lowered by two Worm Drives that are approximately 33 feet apart, so it’s a large gate. Pictured (above right) is one of the worm drives.
The drive motor and gearbox are mounted in the middle and the complete system is being replaced. As with any machinery installation work there will be a lot of alignment work required, including the two drive shafts which are 176 inches in length.
Chad Hansen of CH Mechanical was asked to do the shaft alignment work on the complete drive. Chad owns an EASY LASER XT660 shaft alignment tool which can cover a measurement distance of over 66 feet. He is confident he can do this work however, as the largest span from worm drive to worm drive is 33 feet. But the work doesn’t start on site, it starts back in the shop.
This is the drive assembly (image below) for the two jackshafts that drive the worm drives, which opens/closes the gate. A new base had been fabricated, which in its self is a nice piece of work! Notice that it has four different levels with machine components attached. That’s 8 mounting foot pads, one for each mounting bolt. Each of these mounting surfaces should be flat. Each set of mounting pads should also be coplanar; for example, the four foot pads for the motor should be flat. I could go on about the importance of base flatness but i’ll leave that for another post!)
Now let’s look at the machine’s components. A good-sized motor with standard mounting feet has a shaft coupled with a chain coupling. This connects to the short spacer shaft supported by two pillow block bearings. This is coupled with a flange-mounted rigid coupling which then connects to a drum brake that is mounted on the gearbox input shaft. Now for the gearbox. The one output shaft is obvious, coming out of the front side of the gearbox (left side of image) with the shaft parallel to the motor shaft. The other shaft is harder to see, on the opposite side, under the drum brake pedestal running underneath the motor. The motor and pillow block base will be removed during the installation but this pre-assemble is to make sure it all fits without being bolt-bound or base-bound.
The most important aspect of this machine’s installation is mounting the gearbox and setting the brake, and that where Chad starts. The gearbox input shaft must be parallel with the mounting surface of the brake. This can be achieved by shimming the gearbox and/or the brake. It’s usually a combination of both to get the optimum move but its time well spent. The end goal is that there is no gearbox shaft deflection when the brake is applied. This means no angle or offset. Next, the spacer shaft is aligned to the gearbox shaft. This is a rigid coupling, so it is best to do this with the coupling open (separated). This is done by using the two built-in electronic inclinometers in the measuring units and either the 9-12-3 measurement method or EasyTurn measurement method. Either way you get a high accuracy, repeatable alignment.
After this you can align the motor to the spacer shaft. With the Easy-Laser XT660 Shaft Alignment tool Chad has different measurement method options because this alignment work is important. Here, he can use the multipoint measurement method and take a series of measurements. He can align the motor to the spacer shaft then go over the top to align the motor to the gearbox shaft, his choice. He can use the new ANSI standard tolerances which is in the display and will be shown in the report.
The whole gearbox and drive assembly are installed on site. However, the bearing pedestal, motor, and motor base has been removed for easy access (image, below left).
The right-side jackshaft is installed first, that’s the one closest to the dam. You can see the moveable laser/detector unit mounted on the output shaft just below the drum brake. The worm drive (image, above right) will be the stationary machine with the other laser/detector mounted. The laser alignment data is collected using EASY-LASER’s EasyTurn measurement method with the results showing the amount of misalignment and in which direction they need to move the machine.
The alignment work is completed. There is a little wiggle room at the worm drives however, most of the corrections are made by moving the drive assembly. CH Mechanical uses the new ANSI alignment tolerance for spacer/jackshafts. They are well within spec so it’s a job well done. The actual numbers remain the property of the Dam, so we won’t publish them. However, there is a lot of margin on a 176-inch shaft length. That’s not to say that it’s a quick job, its not. Its actually a very complex job made easy by Chad Hansen and his EASY-LASER XT660 shaft alignment tool.
Thank you John Lambert with Benchmark PDM for sharing this successful story with us!
by Diana Pereda
Ultrasound is a guide to precision grease replenishment in motor bearings. It is also known for its versatility for leak detection, valve assessment and electrical fault detection.
Acoustic lubrication is an integral component of ultrasound programs. Fewer than 95 percent of all roller bearings reach their full engineered life span, and lubrication is the culprit in most cases. In fact, poor lubrication practices account for as much as 40 percent of all premature bearing failures. Yet, when ultrasound is used to assess lubrication needs and schedule grease replenishment intervals, that number drops below 10 percent. What would 30 percent fewer bearing related failures mean for an organization? Download our 5-STEP Acoustic Lubrication Procedure – An effective lubrication procedure to grease bearings right
To understand the role precision lubrication plays in bearing life extension, it helps to understand basics of bearings, their lubrication mechanism and how ultrasound helps.
The insides of a bearing consist of four components. The inner and outer raceways form a path for the rolling elements to glide on a thin film of lubricant. A metal cage separates the rolling elements, keeping them evenly spaced to distribute the load and stop them from crashing into one another. These components move in concert producing frictional forces from rotational inertia, surface load, misalignment, imbalance and defects. Zero friction is impossible, but optimal levels of friction are achievable with correct installation techniques and proper amounts of lubricant. Download our Induction Heating Procedure – Bearing Mounting – A simple and safe procedure for proper bearing installation
Ultrasound works on the FIT principle—it responds well to defects that produce friction, impacting and turbulence (FIT). For motor bearings, two of these phenomena apply: friction and impacting. Ultrasound detects high-frequency signals produced when two surfaces slide together or come in contact with any force. Stage 1 bearing failures happen at the micro level. Because ultrasound ignores low-frequency audible signals, it forms the perfect companion for measuring, trending and analyzing defects despite high levels of noisy interference encountered on the factory floor.
Ultrasound detectors detect friction and impacting as acoustic energy from rolling friction and defect impulses. When lubricant levels are optimum, the energy created is at its lowest. As frictional forces increase, so does the acoustic energy. Ultrasound instruments measure friction and impacting as energy using the scaled value dBµV (decibels/microvolt). The results are presented as condition indicators, and there are four of them:
Condition indicators are most responsible for transforming ultrasound technology from a simplistic, “point the gun and pull the trigger” gadget, to being recognized as analysis and trending technology. Condition indicators add validity to trending by going beyond the single decibel. If a user currently uses an ultrasonic gun that does not have condition indicators, they should question the data. Click here to read the entire article “Use Ultrasound to Optimize Grease Replenishment”
by Diana Pereda
Understanding the Key Components of an Effective Lubrication Program
Lubrication is often overlooked in organizations. Why it is overlooked, I am unsure. Maybe it is because it is considered to be a basic job, given to the apprentice, or it is just too simple to not to do it correctly.
However, with a focus on lubrication, many failure mechanisms can be reduced and the equipment life prolonged. But implementing an effective and world-class lubrication program is not simple. It requires a dedicated focus to implement and sustain. Below is my list of what I look for when evaluating a lubrication program.
Effective lubrication takes many of the practices mentioned above and provides a governance framework to support and ensure it is executed as designed. With an effective lubrication program, the organization should see an increase in uptime, a reduction in lubrication consumption and a reduction in the number of lubricants on site. These changes enable the organization to operate more efficiently.
To begin the journey to improve your lubrication program, you do not need a full assessment and massive project. Take one of the items above, learn more about it and start a pilot. Make sure to build a business case with your pilot to capture the benefits and use that as a basis to build the business case for the larger project.
Thank you James Kovacevic with Eruditio LLC for sharing this informative article with us!
by Diana Pereda
We used to assume that once equipment is installed and aligned, it will remain in the same position forever. But this is not always the case.
The alignment should be checked periodically. This valuable information will help you to find problems like pipe stress, unstable foundations, weak frames and loose bolts, among other problems. All the efforts to align your equipment and keep it within tolerance will be worthless if your machinery can’t keep its position. Therefore, the repeatability of the alignment check is your best ally to see how the equipment behaves.
How often should you check?
There are guidelines for how often the alignment should be checked. According to John Piotrowski in his Shaft Alignment Handbook, for newly installed machinery the alignment should be checked after 500 to 2000 hours of intermittent operation, or 1–3 months of continuous operation. If there was no apparent shift in the alignment, then next check should be made at between 4500 and 9000 hours of intermittent operation or 6 months to 1 year of continuous operation. If no apparent shift occurred at any time, then checks should be made every 2–3 years. This interval can of course be influenced by factors such as equipment criticality etc.
If a moderate shift in alignment occurred at any time, then the equipment should be realigned to within acceptable tolerances. If a radical shift occurred, then additional investigation should begin to determine what is causing the shift – a root cause analysis. For example, any indication of excessive wear and tear will also be an indicator of a “non-healthy” machinery installation.
The importance of documentation.
To have properly documented alignment checks is essential to avoid repeating the same installation errors, or to discover and follow up on recurring problems. Of course, there is no exact answer to the headline question. But the documentation will give you a very good understanding of what happens along the way, and help you keep your machinery aligned as long as possible.
Thank you Roman Megela with Easy-Laser for sharing this informative article with us!
by Diana Pereda
We’ve all read about it: leak detection should be a top priority since leaks can account for up to 30 to 40% of consumed volume… So, why is this issue still on the table? Why is it difficult to change things in the field?
In industry, one of the most common applications for ultrasonic detectors is to search for leaks to achieve greater energy savings. For both service providers and maintenance engineers, the hardest task is not so much to localize the leaks, which is child’s play if you have the appropriate tool, but to generate a report of the problems found, organize the required repairs and communicate the resulting savings to management and others within the company. A company-wide cost reduction program will be efficient only if all stakeholders are involved. When the implementation of an efficient program aiming at minimizing the energy costs related to compressed air fails, it is not due to technology, which almost never fails, but to human factors. All surveyed companies that had initiated a leak detection program that did not last over the long term had something in common: a lack of communication.
The successful implementation of an energy-saving strategy relies on good communication between all stakeholders, directly or indirectly. What you need to do is involve five different persons or groups, each having a very specific role to play in this campaign. The first person is the Ultrasound Inspector: he/she knows the network and where to find the losses. The second person is the Purchasing Officer: he/she buys the equipment required to manage the program and possibly negotiates power supplies. The third person is the Maintenance Planner: he/she will schedule the repairs to be done after inspection of the network. The fourth group is the Maintenance Supervisor and Technician(s) who will repair the defects that have been localized. The fifth person involved is the most important one: he/she is the Executive Sponsor whose role is to motivate and drive the project and communicate the savings achieved to all concerned. By highlighting these savings within the company, he/she will make the project come alive with visible and measurable results.
It’s easy to say, but in reality takes a lot of time and organization. However, since the advent of smartphones, tablets and other connected devices in the maintenance world, you can now use free assistance tools available as iOS/Android applications to measure leak-induced costs and document them with pictures. These applications can also be used to assist the various stakeholders and monitor the different steps to complete the implemented program (e.g., LEAKReporter, LeakSurvey). These tools are now able to automatically assess the costs of the defects detected over an entire year. Communication between all departments affected, directly or indirectly, by the program is now simple and natural.
In 2018, we worked with a company located in the North of Manchester, England, which, for many years, has used measuring instruments to detect leaks. However, no energy savings have been observed nor measured. As a result, the team was experiencing a loss of motivation and had given up on its cost reduction strategy. Thus, our customer’s request was simple: give a new life to their projects. The first steps consisted in clearly redefining everyone’s role. The second step was to train the team in the use of newly available tools: leak detector and mobile applications. The third step was to set up a “think tank” inviting all stakeholders to reflect on the best approach to adopt to manage and organize a leak detection campaign before, during and after our intervention (see diagram below). Finally, the fourth step was to celebrate our results with all the persons involved in the project. After two days on site, everyone precisely knew what was expected of him/her. 17 leaks were localized, representing potential yearly savings of 3,934 GBP (4,481 EUR or $5,111 US) and, after the quick repair of 7 leaks; actual savings of 1,648 GBP (1,877 EUR or $2,142 US) were quantified. As a result, the inspector has a better control of his/her network and of compressed air losses and actual needs; the purchasing officer can calculate the return on investment; the technician feels valued by the savings generated from his/her work; and finally, everyone is thankful to the sponsor for (re)establishing communication between the different departments.
Automatic savings sheet and automatic work order were generated by the SDT LEAKREPORTER mobile application.
Loss (£/year) = $249 US
We also share with you our LEAK MANAGEMENT: FIND-AND-FIX LEAKS PROCEDURE: An effective way to survey your systems and detect leaks.
Thank you Benoît Degraeve with SDT Ultrasound Solutions for sharing this case study with us!
by Diana Pereda
It is important to ensure that the top cover mounting surface, machine sole plates and rails, and main bearing “landings” of a compressor frame are installed as flat as possible. This ensures that the main bearing bores and internal components remain undistorted and aligned as per their factory specifications.
Ariel Compressors have a strict tolerance for the top rail alignment, and their ER-82 document discusses this in detail. Essentially, if the top rails are flat, the main bores will be as well, and provide a proper run condition for the crankshaft and bearings. There are many ways to perform a flatness check so long as the equipment used meets the Ariel guideline for accuracy. Some people have chosen an inclinometer-based system but systems like the Easy-Laser XT770G add a new dynamic in versatility. When checking a large frame like an Ariel KBB the XT770G gives the user consistent, reproducible measurements they can trust to make critical adjustments. By looking at the elevation of individual points, instead of the rise-over-run between them, the actual repair is made much easier.
The initial setup of the XT770G for a top rail measurement is simple. Because the Laser Transmitter is on a magnetic tilt table, the system can be put anywhere within line-of-sight for the rails to be measured— even on the rails themselves. Either a plate or a tripod may be used to position the laser. Before placing the sensor on the rail via magnet, you want to make sure the rails are clean and free of debris or excess oil. Once the rails have been cleaned the XT770G is bucked-in, to establish a plane that is reasonably parallel to the surface of the compressor. The system is now ready to take measurements for the required points. The number of points is determined by Ariel, based on the frame model.
Once set up, measurements with the XT770G take less than 5 minutes on a KBB frame or other large scale compressors, due to the freedom of a powerful Bluetooth connection. With the measurement data recorded, adjustments can be made by viewing the information in the rugged XT11 computer or the free iOS and Android applications. Several options are available for referencing the data, such as an All Points Negative, All Points Positive, Best Fit Around Zero, or even Custom Reference Points. These numbers can be plugged into the ER-82 spreadsheet. Reporting may also be done in the field through the USB option, or sent directly to an email address using the Wi-Fi embedded in the XT11 computer. The PDF report is ready to be imported into any work flow management software, keeping all measurements easily documented and ready to archive.
by Diana Pereda
The SDT270 system was used to collect ultrasound data at a methane plant for start-up and commissioning of newly installed equipment to get a baseline condition on the motor’s and gear reducer’s bearings and gears. We were immediately able to pinpoint a defect in the drive end motor bearing using the SDT270 as well as collect and record a sound file (play below) and present it to the customer.
After removal and inspection of the motor bearing it was found that the motor had been stored in a basement and got water into it through the electrical conduit during a monsoon storm that flooded the facility in late summer, causing the bearings to rust and corrode. It was also found that the electrical disconnect box for the motor had water in it as well.
Pump: Progressive Cavity Seepex Pump
Motor: WEG 75HP 1775 RPM
Not only were we able to identify a bearing fault but also the “smoking gun” root cause, thereby thwarting further damage in the electrical system.
After troubleshooting the entire facility we were able to save several other motors stored in the basement that had also had water exposure through the electrical conduits.
Thank you Brian Franks with JetTech Mechanical LLC for sharing this success story with us!
by Ana Maria Delgado, CRL
A couple of months ago, we were hired to perform an alignment on a motor/gearbox setup with a 9-foot spacer coupling in between. The obstacle this time around was that the spacer coupling was going through a steel support beam. The coupling is round but the hole in the beam was square, just big enough for the coupling to go through. With a circle going through a square, only the corners of the hole were open. This meant that line-of-sight between the two lasers was limited. Because of the obstruction there was no way to obtain data with a continuous reading. Using our dual-laser XT660 system, we decided to take readings in each available corner. We could have taken one point at each 45 degree position. However, taking more points is always beneficial. We decided to take three points (close together) in each of the corners. With two rotations, we obtained excellent repeatability. Once we had repeatable readings, we moved the machine according to the calculated alignment results and aligned it to our customer’s customized tolerances.
Many times we are faced with awkward alignment situations. It is helpful to have an alignment tool that is very easy to use, yet versatile to adapt to these situations. It helped that the Easy-Laser® XT660 allowed us to change measurement modes (in this case to Multipoint mode). It also helped that the tool allowed us to adjust our tolerances to the customer’s particular needs. The customer did not want to use the built-in Easy-Laser tolerances, nor the ANSI standard tolerances that are included in the system. Instead, they were looking to align the machines to within 0.1 thou/inch (or 1.0 thou/10 inches) of angular misalignment at each flex plane. So we created a custom tolerance instantaneously within the tool for this job. The customer was satisfied with the alignment and the report generated with their tolerances.
Learn more about Precision Alignment from Adam Stredel at our Rethink Maintenance Training Roadshows
by Ana Maria Delgado, CRL
December 2018 – EFFICIENT PLANT
The recently released Alignment Standard (ANSI/ASA S2.75-2017) from the American National Standards Institute, Washington (ansi.org) took nearly three years to develop. A committee of alignment experts discussed every aspect from safety procedures to the mathematics involved in defining the new standard. Alan Luedeking, CMRP, CRL, of Ludeca Inc., Miami (ludeca.com) a member of that committee, has been involved in the development of alignment standards for significantly longer than three years.
Luedeking remembers the “old days” well. Back then, personnel simply aligned components to the best of their abilities with straightedges or dial indicators. “Those alignments,” he said, “usually weren’t that good, due to sag, span limitations, obstructions to rotation, or whatever. But you did the best you could, and that was good enough because it was all you could do.”
In 1982, Ludeca introduced the world’s first computerized dial indicator alignment system (from the now-defunct Industrial Maintenance Systems Inc.), followed in 1984 by the world’s first laser-alignment system. With the improved measurement resolution and accuracy afforded by the laser sensor, a more precise definition of what constituted a good alignment became necessary. So, according to Luedeking, after poring through the sparse alignment literature that existed, Ludeca developed tolerance tables for short and spacer couplings, which, for lack of anything better, end users readily accepted. “Over time,” he noted, “these tolerance values came to be accepted as the U.S. industry standard and were adopted as the official tolerance standard by various corporate and government entities, including NASA and the U.S. Navy.”
So what are alignment tolerances, and why are they important? As Luedeking described them, “Tolerances exist because absolute perfection does not. No matter how hard you try and how long you work, you will never get a shaft alignment absolutely perfect.” He offered the following detailed discussion as to why, along with some expert advice on the meaning of the new standard and how it can help you improve your operations. Read the entire article “Alignment Tolerances Carved in Stone”
Check out the Easy-Laser XT Series, the only laser alignment platform on the market today with the new ANSI alignment tolerances built-in giving the user the freedom to choose between traditional tolerances, the new ANSI standards, or custom tolerances of the user’s own choosing.
by Ana Maria Delgado, CRL
We just returned from performing a stern tube bearing carrier alignment on a large container vessel currently in construction at a leading US shipyard. The one-meter diameter bearing carriers needed to be set to specific tolerances with respect to an established datum line along the longitudinal axis of the ship. Historically, this was accomplished using optics, piano wire and depth gauges. The procedure was time consuming and considering the sizes of some of the vessels being fabricated, performing an alignment was tedious and time consuming work. Sunlight on the hull can cause considerable movement; therefore a faster alignment process would be desirable. Therefore, we were asked to bring in the Easy-Laser E950-B bore alignment system. The quick setup and operation of this wireless laser alignment system made taking bore straightness readings a breeze, saving valuable time on a warm sunny morning in dry dock. The client was pleased with the speed with which the job was performed and the ease of understanding results—a testament to the straightforward design of the E-Series software.
by Yolanda Lopez
Guest Post by Bob Dunn from I&E Central, Inc.
I had the opportunity use the Easy-Laser XT440 to assist a customer aligning a machine that had perpetually given them problems, with bearings always running hot. They had recently aligned the machine with dial indicators, but when we checked, it was off by .007, and this on a 3600 RPM motor. We removed their old shims and did a soft foot check indicating .032 under one of the feet. Further inspection showed an angular gap under one foot. It turns out that when new, someone had ground down the feet on the motor to better align to the pump – obviously not a precision job. We step-shimmed to fill the angular gap, then aligned the machine in a single move. Several of the techniques we used were unfamiliar to these mechanics.
by Ana Maria Delgado, CRL
As Published by Solutions Magazine March/April 2018 issue
by Ana Maria Delgado, CRL and Shon Isenhour, CMRP CAMA CCMP, Founding Partner at Eruditio LLC
During the many root cause analysis (RCA) investigations we facilitate and coach, we notice some themes that continue to manifest themselves in the findings. Often, they are grouped under the heading of precision maintenance or lack thereof. Let’s take a look at some of them and determine if they are also killing your reliability.
The six killers are grouped into three areas: Lubrication, Misalignment and Undiagnosed Wear.
Click here to read the full article.
by Ana Maria Delgado, CRL
Recently I have been seeing the P to F interval curve popping up a lot on my LinkedIn feed and in articles that I have read. It was a concept that I was first introduced to when I was implementing Reliability Centered Maintenance into the Engineering and Maintenance department at the plant where I worked at the time. It was a great idea, that if done correctly is maintenance benefit. Why, because its cost savings and cost avoidance. Let me explain this.
The P to F curve was used as a learning tool for Condition Based Maintenance. The curve is the life expectancy of a machine, an asset. The P is the point when a change in the condition of the machine is detected. The F is when it reaches functional failure. This means that it is not doing the job it was designed to do. For example, if it were a seal that is designed to keep fluids in and contamination out and is now leaking, its in a state of functional failure. Will this put the machine down? Probably not, but it depends on the importance of the seal and the application. This is an important point because the P (potential failure) is a fixed point when you detect the change in condition but the F (failure) is a moving point. Not all warnings of failure put the machine down very often you have options and time. Consider this: If I have a bucket that has a hole in it, it is in a functional failure state. But can I still use it to bail out my sinking boat? You bet I can!
Failure comes at us in many ways and obviously we have many ways to combat it. If you detect the potential failure early enough (and it can be months and months before actual failure) it means that you can avoid the breakdown. You can schedule an outage to do a repair. It’s not a breakdown, the machine hasn’t stopped, it’s not downtime. This is cost avoidance and the plant can save on the interrupted loss of production because of downtime costs.
There are a lot of examples of cost avoidance and also of cost savings. For instance, at the plant I worked at we used ultrasound to monitor bearings. We detected a very early warning in the sound level and were able to grease the bearing and the sound level dropped. We saved the bearing of any damage, we saved a potential breakdown so this is cost savings. Even if there is some bearing damage, the fact that we are aware and monitoring the situation lets us avoid any secondary damage.
It’s one price to replace a seal and its more if you have to replace a bearing in a gearbox. However, it can be very expensive to have to replace a shaft because the bearing has sized onto it ruined it. Secondary, ancillary damage can mount up very quickly if you don’t heed the warning you are given with the P of potential failure. This warning of potential failure gives you time before any breakdown. The earlier the detection, the more time. Time to plan, view your options. And what people tend not to do is failure analysis while the machine is still in service. A failure analysis gives you a great start on seeking out the root cause but start right away, not when the machine is down.
Condition monitoring or as its often called Condition based maintenance (CBM) does work. However, for me there is a down side to this and I will explain why shortly. CBM is based on measurement, which is good because we all know to control a process we must measure.
Consultants (and I’m guilty) like to put labels on things and you may see:
1. Design, Capability, Precision Maintenance
2. CBM, Predictive Maintenance
3. Preventive Maintenance
4. Run to Failure, Breakdown Maintenance
For me the P to F interval curve starts when the machine starts. That means Design and Precision Maintenance is not in the curve and this happens before startup. A small point but it takes away from the interval meaning.
We use predictive maintenance technologies in CBM. Vibration, Ultrasonic, Infrared, Oil Analysis, NDT (i.e. pipe wall thickness) and Operational Performance. They are all very good technologies, yet it is a combination of cross-technologies that works best. As an example, vibration may give you the most information yet ultrasound may give you the earliest warning on a high-speed bearing. And then there is oil analysis which may be best for a low-speed gearbox. It all depends on the application you have which dictates what’s best for you. A lot of time and effort was placed on having the best CBM program and to buy the right technology.
This, I believe, lead to the maintenance departments putting the focus on Condition based maintenance! This I think is wrong because we still have failure. This means that CBM is no better than Predictive Maintenance. This doesn’t mean that I don’t recommend CBM, I do. To me it’s a must have but it does not improve the maintenance process because you still have machine failure. Machine failures fall into three categories Premature failure, Random failure and Age-related failure. We want the latter of these. We know from studies that say that 11% of machine assets fail because of age-related issues. They grow old and wear out. This means that 89% fail because of some other fault. This is a good thing because it gives us an opportunity to do something about them.
These numbers come from a very famous study by Nowlan and Heap (Google it!) that was commissioned by the US Defense Department. It doesn’t mean these numbers are an exact refection for every industry but the study but it has stood the test of time and I believe it has lead to the development of Reliability Centered Maintenance. But let’s say its wrong and let us double the amount they say is age related (full machine life expectancy). That would make it 22% and 78% would be the amount of random failures. Even if we quadruple it its only 44% meaning random is at 56% and we are still on the wrong side of the equation. The maintenance goal has to be to get the full life expectancy for all their machine assets.
In order to get the full life expectancy for a machine unit I think you have to be assured of two things. One is the design of the unit which includes all related parts (not just the pump but the piping as well). The other is the installation.
If you’re like me, and you believe that Condition Based Maintenance starts when the machine starts then you understand that there is a section of the machines life that happens before. You could make an argument that it starts when you buy it because, as we all know, how we store it can have an effect. However, what is important at this stage is the design and installation of the machine. In most cases, we do not design the pump, gearbox or compressor but we do size them so that they meet the required output (hopefully). We do quite often design the piping configuration or the bases for example. All of which is very important but the reality is that maintenance departments maintain already-in-place machine assets. So, although a new installation, requiring design work is not often done, installation is. Remove and Refit is done constantly. And the installation is something that you can control. In fact, it’s the installation that has the largest influence on the machines life. The goal is to create a stress-free environment for the machine to run in. No pipe strain, no distorted bases, no thermal expansion, no misalignment, etc.
Precision Maintenance was a term I first heard thirty years ago. Its part of our M.A.A.D. training program (Measure, Analyse, Action and Documentation). It’s simple, it means working to a standard. Maintenance departments can set their own standards. However, all must agree on it and adhere to it. This is the only way to control the installation process. This is the way to stop random failure and get the full life expectancy for your machine assets. The issue is that we do not have a general machinery installation standard to work to. Yes, we can and use information from other specific industry sources such as the American Petroleum Institute (API) or the information from the OEM (both of these are guidelines) however nothing for the general industry as a whole. Well this is about to change. The American National Standard Institute (ANSI) has just approved a new standard which is about to be published. I know this because I worked on it and will be writing about it shortly.
If you look at the life cycle of a machine, we need to know and manage the failure as best we can. If we only focus or mainly focus on the failure, we will not improve the reliability of the machine. We cannot control the failure. What we can control is the installation and done correctly this will improve the process giving the optimum life for the machine.
I sell laser alignment systems as well a vibration instruments. If a customer were to buy a vibration monitoring tool before they bought a laser system. I would think their focus is on the effect of the issue not the cause. What do you think?
by Ana Maria Delgado, CRL
Guest post by Bob Dunn at I&E Central, Inc.
I was working with a customer to align sheaves using their Easy-Laser E180 sheave alignment tool. This is a new blower that had been installed by a contractor. Obviously the contractor did not check alignment before drilling the mounting holes. The horizontal angular error was about 1.25 degrees and required a move of about 1/4″ more than was available given the placement of the bolt holes. Thanks to the digital measurement of the E180, they knew exactly what correction was needed at the feet to align this machine.
Unfortunately, the solution will be to drill out the holes in the base, then complete the sheave alignment. What should have been a 30-minute job now becomes a much larger project – time and money wasted. My guess is that the contractor checked alignment with a string (or maybe not), which did not get him close enough. Using the right sheave alignment tool makes a difference.
Thanks to Bob Dunn for sharing this case study with us!
by Yolanda Lopez