Blog

As Published by Maintworld March 2018 issue

CRISTAL UNION (CU) is an agroprocessing cooperative company ranking among the top European sugar and alcohol producers.
Most of its facilities are established in France (18 sites). The BOURDON site in AULNAT (in the Puy-de-Dôme département) has a production capacity of 4,500 tons of beets per day.

The company contacted SDT Ultrasound Solutions regarding the implementation of a preventive maintenance program based on the collection and analysis of ultrasonic signals. This project dealt with about 400 rotating machines.

Background
After purchasing an SDT270 ultrasonic data collector and its analysis software tool, SDT and CU have defined the outline of a training program suited to the monitoring of rotating machines. The first step consisted in creating a database containing all 300 machines and then, performing the first data collection in order to determine the initial mechanical condition of each bearing. After simple on-site analysis (ultrasonic listening) and more detailed analysis (overall or static measurements and spectral or dynamic measurements), 1 800 thresholds were defined (pre-alarm, alarm and danger).

Using these background data, technicians were then able to identify, at a glance, the machines having an alarm condition.

Click here to read the full article.

by Yolanda Lopez

While we’ve been using calendars and calculators to determine grease replenishment requirements in bearings for a long time, this science is wrong. Most bearings never reach their L10 engineered life, and poor lubrication practices are attributed as the primary failure cause.

Bearings fail when they are over-greased. We lubricate them too often, and we use too much grease.

Change Your Thinking.
We lubricate bearings to manage friction, but over time, grease gets old and needs replenishment. The first sign is when friction levels increase. Ultrasound performs well at sensing and measuring changing in friction levels. It’s the perfect technology to guide lube technicians during the lubrication-replenishment task.

Lubrication Solution
We want to grease bearings correctly. That means using the right grease, at the right location, following the right procedures and intervals, injecting the right amount, and receiving the right feedback when the task is done. New technologies from SDT are engineered to do just that.

The days of relying on calendars and calculators are over. Use our 5-Step Acoustic Lubrication Procedure  and start greasing bearings the right way!

Download our Ultrasound Lube Technician Handbook to learn more!

by Yolanda Lopez

  1. Prevent metal-to-metal contact (which creates wear particles) by using condition-based lubrication through ultrasound. Ensure the proper oil viscosity and additive package is selected and that the bearing load does not exceed its design capacity through proper installation, alignment, balancing and operation.
  2. Use desiccant breathers.
  3. Adopt an aggressive fluid management program that establishes acceptable ISO cleanliness targets for new oil by machine type. Take care to use methods of adding and sampling oil that minimize contamination ingress. These include quick connect couplers and point-of-use filtration. Install an oil recirculation system to remove particles as soon as they are created and introduced.

by Yolanda Lopez

Compressed air is the fourth most commonly used source of energy in industry. Walk through any facility and see miles of pipe transporting this house-made energy source to its point of use. On this journey its fate is undecided. Will it arrive to deliver the intended value? Or is it lost along the way?

Why Do We Tolerate Leaks?
On average, 40% of compressed air goes to satisfying the false demand of leaks. Why do we tolerate this waste in an otherwise efficient economy? Lots of reasons.

  1. Low Safety Risk?—Compressed air Leaks are rarely considered a risk. Odorless and colorless, they don’t make a mess on the floor, and we can’t hear them over plant noise.
  2. Lack of Education—Many believe compressed air is free. Yet a leak costs a thousand times more than lights that are left on.
  3. Complacency—The reliability culture does not always extend to the compressor room. Energy efficiency must be written into an organization’s aims and objectives.

Facts and Figures Don’t Lie.
Air is free. Compressed air is not. It requires another energy source to compress it. How much energy? Here’s the cost breakdown of a typical compressor system:

  • 13% CAPEX
  • 12% Maintenance
  • 75% Energy
    A small compressed air leak can cost $2,000+/year. Consider that hundreds of leaks may exist in your facility. What are you waiting for?

Leak-Management Solution
Manage your leaks with ultrasound. Their turbulent flow produces sounds that generate peaks in the 35kHz to 40kHz range—exactly where SDT’s ultrasound detectors are engineered to perform. SDT pinpoints leaks at their source, regardless of background noise.

Use our Airborne Ultrasound Leak Management: Find-and-Fix Leaks, and start reducing waste plus save money!

Download our Leak Surveyors Handbook to learn more!

by Yolanda Lopez

Are you adding grease to a bearing and not hearing any changes from your ultrasound equipment? If so, start wondering where the grease is going. It is a fact that if grease gets into a bearing the ultrasound decibel will either go down on a bearing that needs grease or go up on a bearing that is already over-lubricated.

Look for a blocked grease tube. Grease may be going into the windings on an electric motor. Do you see grease on the tube of the grease gun? Maybe a greaseable bearing was replaced with a sealed bearing at the motor shop after a repair. These are just some of the things you need to consider if you get no ultrasonic decibel change after injecting grease to a bearing.

Download 5-Step Acoustic Lubrication Procedure

by Yolanda Lopez

The diesel engine is the heart of heavy construction equipment and replacement costs are in the millions. Ingress of dust due to leaky air intake systems shreds components in short order.  The SDT TIGHTChecker quickly and easily pinpoints leaks in the air intake system.

Dust is no friend to a diesel engine. But when the integrity of the air breather and turbo charger is compromised by leaks, microscopic grains of silica and other contaminants are sucked inside. There, they wreak havoc on the engine’s internal components costing organizations millions of dollars in premature wear and downtime.

Worse yet, you may not even realize you have dust ingress unless you are conducting regular oil analysis. These leaks are nearly impossible to find using conventional methods. Visual inspection takes hours and is often unsuccessful. Production does not have the patience to wait. They need that asset back in the field, leaks or not.

But what if there was a way to identify those leaks in minutes, instead of hours? SDT Ultrasound Solutions teamed up with mining giant Rio Tinto in Labrador, Newfoundland to devise a simple procedure for identifying turbo leaks in the engines of their huge loaders.

Using SDT ultrasound technology, a transmitter is placed inside the air filter basket. The high frequency sound waves are contained inside the piping unless there is a leak. Any microscopic air gap in the pipe is instantly recognized by the handheld flex ultrasound detector.

An 8 hour inspection that often ended in frustration is now a worldwide success story that continues to save Iron Ore Company of Canada $8 million per year.

by Yolanda Lopez

Guest Tip by Bob Dunn from I&E Central, Inc.

In some environments, reflected sounds can make it difficult to locate a leak.  If you are in a confined area (a smaller room, or beneath/inside a machine), the leak can seem to be almost anywhere.  A good solution is to adjust the sensitivity downward.  Ultrasonic sounds will reflect, but lose energy each time they reflect.  By reducing sensitivity, the reflected sounds drop into the background, allowing you to locate the actual source of the leak.

Note that SDT inspection tools have separate adjustments for sensitivity and headphone volume, so you can manage sensitivity without affecting your ability to hear!

Download our Find-and-Fix Leaks with Airborne Ultrasound Infographic!

by Ana Maria Delgado, CRL

Question: When is it OK to over-lubricate your bearing?

Answer: NEVER!!!!, (almost) the exception is when high vibration exists.

If you attended the SDT/LUDECA Acoustic Lubrication Workshops then you now understand grease as a lubricating mechanism. You understand that the Churning Phase of the lubrication task is inevitable, and long-term, detrimental to the health of the grease. Therefore, we want to move as quickly as possible from the Churning Phase to the Bleeding Phase. This is the natural progression of precision lubrication.

Grease is not a robust grease mechanism. It is actually quite fragile compared to an oil only system. But we need grease as a lubricating mechanism in bearings because the properties of grease help to keep the lubrication in and around the warzone while sealing out contaminants.

Vibration is inherent in every machine system. Excessive vibration however, negatively impacts the ability of grease to lubricate. Some machine systems are intentionally vibrated as part of their function and process. Other equipment vibrated excessively because of a defect such as imbalance, misalignment, poor installation, or poor workmanship. For these machines, it might be best practices to over-grease their bearings.

I know that sounds counter to what we teach and know, but consider this. It is better to have thickener and oil in the warzone of the bearing, than it is to set up a bleeding mechanism and have the reservoir destroyed because of high vibration. If we let this happen we may never get any oil where it’s needed.

High vibration? Slightly over grease your bearing and allow a little thickener to exist in the warzone. It is the best compromise.

Download our 5-Step Acoustic Lubrication Procedure.

by Yolanda Lopez

There are 3 techniques that can facilitate your work in the field: the shielding technique, the covering technique and reflection management.

Shielding technique protects sensor from parasite ultrasound

1. Shielding technique

This technique greatly reduces the influence of interfering leaks. It consists in using a piece of cardboard or foam(*)… to create a barrier between the “parasitic” leak noise and the location where you want to detect/locate a leak.

(*) Any material will work. It will reflect approximately 90% of the energy coming from the interfering leak.

Practical advice: the precision indicator tip placed on the internal or flexible sensor acts as a shield. This technique is very useful when leaks are very close to one another.

Covering technique blocks a known leak from disturbing detection of other leaks in proximity

2. Covering technique

This technique also greatly reduces the influence of interfering leaks. It consists in:

Either covering an interfering leak with a rag or glove while you inspect an area.

Or covering the sensor with a rag or glove in the zone you want to inspect.

A leaking valve body can be conveniently covered with a cardboard carton too.

Ultrasound signal reflecting off a wall or hard surface can be tricky

3. Reflection management

When searching for leaks, we sometimes get the impression that a leak is coming from a place where there is clearly no compressed air, such as a wall or a partition. This is due to the phenomenon of reflection. Ultrasounds from the leak are bouncing off the reflective surface. You will find the leak by following the angle of reflection. The angle of reflection is equal to the leak’s angle of origin relative to the reflection surface.

Download SDT Leak Surveyors Handbook to learn more!

by Yolanda Lopez

1. A Change in the Quantity of Grease Consumed
Maintenance departments track their grease consumption to monitor and control costs. A change in consumption is a sure sign that your lubrication program is on the right track.
Most organizations are guilty of over-lubricating. Expect lower grease consumption as your program matures. Bad procedures lead to bearings routinely receiving more grease than they’re designed to handle. The excess ends up being pushed into the motor casing or purged onto the floor.
Over lubrication happens when re-greasing intervals are scheduled based on time instead of condition. Control lubrication tasks with ultrasound to monitor condition and maintain optimal friction. The time between greasing intervals increases, resulting in less grease used per bearing.
2. Fewer Lube-Related Failures
Do you track failures and perform root cause analysis?
Organizations with optimized greasing programs experience fewer lube-related failures. Less fixing and fire-fighting translates to more creative time for maintenance. Use that time to bring more machines into the greasing program.
Additionally, with ultrasound you find many non-trendable defects. For example, broken or blocked grease pipes and incorrectly fitted grease paths prevent grease from reaching the bearing.
3. Optimized MRO Spares Management
Your new and improved lubrication program is delivering wins; better control of grease consumption, fewer failures, and more productivity for maintenance. Use this time to study trends and better manage your storeroom.
A decrease in bearing related failures improves spares optimization. Share your ultrasonic lubrication data with your MRO Stores manager to create a plan to reduce the number of emergency parts on hand.
Since you’re taking stock, why not shift some burden to your suppliers? Ask them to confirm your emergency parts against their own stock. If it can be supplied on the same day then it doesn’t need to be on the balance sheet.

4. Increased Number of Machines Monitored
One benefit of an effective lubrication program is time.
• Time allotted to monitoring machines instead of fixing them.
• Time allotted to correctly assessing the real needs for lubrication.
• Time to look at the big picture.
Take for instance, criticality assessment. Many lubrication programs begin with small steps. All the “A” critical machines receive priority, rightly so. But what about the rest? With more time to plan, organize, and schedule, the number of machines acoustically monitored for optimal lubrication increases.
5. Save Time. Combine Acoustic Lubrication and Condition Monitoring
You worked hard for these results. It’s time to use your data for more than just lubrication.
Acoustic lubrication is the proven method to ensure precise bearing lubrication. New technology from SDT, LUBExpert, combines the power of on-board lubrication guidance with Four Condition Indicators for bearing condition assessment.
The time savings from assessing bearing condition during the lubrication process is beyond valuable and another sign your acoustic lubrication program is on the right track.
6. Inspector Confidence at an All-Time High
Reliable machines are the product of an effective lubrication program. You have:
• Managed grease consumption
• Fewer grease related bearing failures
• Optimized MRO spares
• More machines under watch
• Increased data collection intervals
The power of adding ultrasound to your greasing program delivers win after win for reliability. Reliability breeds confidence. More confident inspectors making the right calls and infecting a positive culture throughout the organization.
 

by Allan Rienstra - SDT Ultrasound Solutions


Plant Engineering, celebrating its 30th anniversary of the Product of the Year award program, announced the results for the 2017 entrants. SDT’s innovative LUBExpert, an ultrasound solution designed to help grease bearings right, was awarded the GOLD medal! The award is remarkable considering the excellent company of peers in the running for Silver and Bronze.
Alex Nino of LUDECA, was on hand at the award ceremony, and looked marvelous! LUDECA is the exclusive distribution partner for SDT Ultrasound Solutions in the USA and were instrumental in architecting this recognition. Chosen from numerous submissions from around the world, Plant Engineering subscribers reviewed and voted on the finalists. LUBExpert received the most votes for this 30th anniversary Grand Award. Congratulations to LUDECA, SDT, and LUBExpert for the GOLD.
Poor greasing practices is a leading cause of bearing failure. LUBExpert is an ultrasound solution designed to precisely guide lube-techs during the lubrication replenishment process. It helps avoid over and under lubrication, while instructing the technician on which grease types, grease guns, grease quantities, and replenishment intervals to use. LUBExpert’s intelligence lends confidence to the task of grease replenishment and is a true innovation for ultrasound technology.

Winning GOLD validates our decision to work with industry leaders such as SDT,” states Ana Maria Delgado, Marketing Manager at LUDECA. “The LUBExpert compliments our full line of predictive and proactive solutions. Its clever innovation supports the leadership position of all our solutions.”

About LUDECA
LUDECA is the premier provider of reliability solutions to USA industry. Their years of experience and wealth of knowledge make it possible to offer the very best service and support to their customers. Their commitment here strengthens their reputation as the very best in our fields. SDT is delighted to be aligned with LUDECA. Our companies share the same principles, philosophies, and values.
About SDT
SDT provides ultrasound solutions that help our customers gain a better understanding about the health of their factory. We help them anticipate failures, control energy costs, and improve product quality while contributing to the overall reliability of their assets.

by Allan Rienstra - SDT Ultrasound Solutions

A proven method to assess gearbox condition is to collect a DYNAMIC ultrasound signal. If possible, you want to capture at least 3-5 revolutions of the gearbox. From there, analysis is straightforward. Use Ultranalysis (UAS2) software to view the signal in the time waveform and spectrum displays. Use the software’s many analysis tools to determine the exact nature of any defects. Just remember these three keys for successful ultrasonic condition monitoring.

1. Collect the best data you can, using a high quality ultrasonic data collector.
2. Consistent sensor placement must fundamentally be observed.

Figure 1 – Time waveform and Ultrasonic Enveloping Power Spectrum of a damaged gearbox from SDT270 and UAS

3. Identifying boundaries that impact data transmission is imperative.
Ultrasound is Shy… It Keeps Boundaries
Think of ultrasound as the quiet introvert. It prefers to stay in, and rarely mixes well with ultrasounds from other places. We call this “boundary behavior” and it’s another characteristic that makes ultrasound such an attractive condition monitoring technology. Ultrasound signals remain isolated to their source, making it easy to pinpoint defects without interference from other elements of the machine.
Sensor Placement
Inspectors tempted to place their ultrasound sensor directly on the gearbox cover, should reconsider. This common mistake affects data integrity. A gasket seals the cover plate to the gearbox housing. The specific acoustic impedance of the gasket material differs greatly from the cast metal of the gearbox. The change in materials a boundary barrier through which bashful ultrasound is reluctant to is pass. A better option is to place the sensor on a bolt head, which is directly connected to the gearbox housing. The result is crystal clear ultrasound signals for listening, trending, and condition assessment. HearMore: Click here to listen to Damaged Gearbox.

Figure 2 – Place sensor on bolt head

Special thanks to our partner Allan Rienstra from SDT Ultrasound Solutions for sharing his great knowledge with us!

by Allan Rienstra - SDT Ultrasound Solutions

Why We Ignore Leaks
Compressed air is a misunderstood utility. As such, it tends to be misused and even abused. Leaks continue to be the biggest problem; often overlooked because they are difficult to detect, don’t smell bad, don’t make a mess on the floor, and rarely stop production.

The Real Cost of Leaks
One of your factory’s highest operating expenses is the energy consumed by your compressed air system. Only 25% of the cost of a compressed air system is capital cost and maintenance. The remaining 75% is energy, and as much as 35% of that energy is wasted satisfying leaks.

Additional Impacts
Compressed air leaks create fluctuations in system pressure, which negatively impacts product quality. Compressors work overtime to compensate, leading to early degradation of the asset. Eventually, the compressor system can’t keep up with demand. What can you do? Buy yet another compressor for more capacity? Or optimize the capacity you already have by finding and fixing leaks?

With so much at stake, why are compressed air leaks managed so poorly, and why doesn’t every organization have an air leak management program?

Where to Look for Leaks
Every component has the potential to leak, but we can hasten our search by focusing on common failure points. Usual problem areas are branch line connections, automatic drain traps, desiccant filters, regulators, coalescent filter assemblies, quick couplers, valves, hoses, fittings, pneumatic cylinders and thread sealants. Most leaks occur at points of use, so begin your search there.

How to Find Leaks
Locating air leaks in a loud factory floor is next to impossible with a human ear. The best, and easiest, way to find air leaks is with an ultrasound leak detector. Ultrasound detectors allow you to hear the minute hissing noise produced by leaks, despite the roaring noise of a production area. Ultrasound detectors are portable, easy to use and require little training to get started.

How to Manage Leaks
It’s not enough to just find leaks. Fixing and documenting savings is a necessary part of the program. One way to justify the labor costs and capital expense is to track them with SDT’s LEAKReporter, a mobile smartphone App available for iOS and Android. LEAKReporter is focused, simple and free. It saves inspectors time and money by documenting leaks in pictures, estimating their cost impact and creating fast comprehensive leak reports.

Being competitive has never been more important than it is today. Energy costs directly impact your bottom line. There is no easier way to reduce energy waste than to tackle the “low hanging fruit” in your compressed air system.

by Tristan Rienstra

Using ultrasound to locate compressed gas leaks is relatively easy, but it occasionally it can present some challenges. The reason ultrasound is so successful is that it is a high frequency, short wavelength signal that does not like to penetrate 2nd mediums. While performing compressed gas leak inspections, keep in mind that strong ultrasonic signals can bounce off most materials leading to false indications.
To overcome this challenge, turn your ultrasonic detector 180° and see if the signal is stronger coming from that direction.
Download Find-and-Fix Leaks Procedure

 

by Paul Klimuc CRL - SDT Ultrasound Solutions

Simon is a condition monitoring specialist from a local oil refinery. He contacted my office for advice about predicting flexible coupling failures. Currently, they perform basic vibration analysis on their pumps and motors using an overall meter. They have some success predicting bearing failures but the same cannot be said for couplings. Several unexpected failures shut them down this year.

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 solution. Specifically, the SDT270DU offered him best value. Not only could Simon use it to monitor couplings with ultrasound; it also takes vibration measurements, thus eliminating the need for Simon to carry two data collectors.

With SDT270 Simon trends bearings with vibration, replenishes lubrication with ultrasound, and finds worn and misaligned couplings.

By placing an airborne sensor near to the coupling Simon can quickly trend an evolving defect. The SDT270DU gives Simon the choice to either spot check for defects – good – or integrate all 58 couplings into his established bearing routes – best.

Find worn and misaligned couplings with SDT’s Flexible Sensor.

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 life cycle trend for each coupling.

Once impacting appears, the Peak indicator increases in step with Overall RMS. Crest Factor (CF) is a comparative ratio between Overall RMS and Peak. As CF trends higher it warns that the window for simple maintenance has narrowed. Inspectors may choose to collect a DYNAMIC measurement when CF alarms are triggered. The DYNAMIC measurement provides a visual representation of friction and impacting severity. For both STATIC and DYNAMIC measurements it’s important to define the signal acquisition time.

Without the ability to define user time, pulling the measurement trigger (M) misses key events
Instead, set the signal acquisition time to suit the asset. This slow speed example used 20sec to capture all defect data. Why use an ultrasound instrument that overlooks the importance of user defined 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 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. One to three seconds at 1800 RPM samples the coupling for 30-90 revolutions.

Shaft couplings are guarded for safety. Any ultrasound inspector working around rotating equipment must be required to demonstrate an understanding of company safety policies. Safety considerations are engineered into SDT sensors. The Flexible Wand’s 10mm diameter sensor is designed to access the coupling with the safety guard in place (see figure 2). The 21” long sensor sports a comfortable, ergonomic grip that allows an inspector to collect danger-free data.

Simon seemed convinced but wanted to Hear More. 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 so 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 primary applications for reliability, represented a fast, safe, and affordable technology with the potential to revolutionize reliability culture. I sat back, happily watching two impassioned specialists strategize about reliability culture. I love my job!

by Allan Rienstra - SDT Ultrasound Solutions

Condition Monitoring Expert Tip #5 by Mobius Institute
Now this is a tricky question to answer… We have a few contenders: high frequency vibration analysis, regular vibration analysis, ultrasound, oil analysis, wear particle analysis, and infrared analysis. Let’s start by ruling a few of them out.

Infrared analysis is used to detect heat in a bearing, which is a late stage fault condition, so that’s not your best option. Regular oil analysis can detect the presence of the wear metals within the bearing, but wear particle analysis is a better tool for that. Regular vibration analysis (i.e. velocity spectra) provide very clear indications of bearing faults, however the high-frequency detection techniques provide an earlier warning. That leaves high-frequency vibration analysis, ultrasound, and wear particle analysis.

Ultrasound is easiest to use. Push the probe against the bearing and listen carefully and you will hear if the bearing is in distress. (You can also record and analyze a waveform, but now you may as well be performing vibration analysis). Many would argue that high-frequency vibration analysis (such as enveloping, PeakVue, shock pulse, and others) provide a clearer indication of the nature and the severity of the fault. But it does require more training and potentially a more expensive system to perform the collection and analysis.

And that leaves wear particle analysis. Let’s just say that if you own critical gearboxes, you absolutely must perform wear particle analysis. Performed correctly, you will detect the first signs of wear, and complex gearboxes provide a greater challenge for the vibration analyst and the ultrasound tools.

Although I haven’t really answered the question, I am hoping to have put you in a position to make the right decision for your situation.
Thank you Mobius Institute for this valuable tip!

by Yolanda Lopez

Condition Monitoring Expert Tip #4 by Mobius Institute

This tip is sponsored by IMVAC (International Machine Vibration Analysis Conference)

There is no doubt that technologies such as vibration analysis, oil analysis, ultrasound and infrared are very powerful. They can tell you a great deal about fault conditions in rotating machinery, electrical systems, and more. But if the criticality warrants it, you will be in a much stronger position if you have multiple technologies indicating that a fault condition exists rather than relying on just one.

For example, if vibration analysis indicates there is a problem in a gearbox, oil analysis can confirm the fault with the presence of wear particles. In the case of vibration analysis, you can utilize high frequency analysis, spectrum analysis, time waveform analysis, and phase analysis to enable you to validate your diagnosis.

There can be a great deal at stake when you make a diagnostic call on a piece of equipment. More so if it is critical equipment. At the very least, a false diagnosis may lead to equipment failure (if you miss the fault condition) or it can lead to unnecessary work and downtime. What’s more, your reputation is at stake. Sadly, people often forget when you make the right call, but it can take years for people to forget when you make the wrong call.

Thanks Mobius Institute for sharing such valuable information with us!

by Ana Maria Delgado, CRL

I often hear the question, “what can I detect with ultrasound?”. The fact is, ultrasound is such a versatile condition monitoring technology we tend to ask it to do things beyond its capabilities. And that’s fine because I firmly believe every technology should be pushed beyond its limits. It’s how we get better.
But to help answer the question, “what can I detect?”, I ask a simple question in return. Is your application FIT?
Now you’re asking “what does he mean by is it FIT”?
Let me explain. FIT is an acronym for Friction, Impacting, and Turbulence. Basically, if the defect you are searching for generates any of these three phenomena, then ultrasound is a solution FIT to solve your problem.
Let’s try a super easy example. You are tasked with finding compressed air leaks in your factory. Air lines run every which way throughout your deafeningly noisy plant so you can’t hear the leaks. You could run your hand along all the pipes and anywhere you feel cool air rushing out you’d know you found a leak. Or you could spray soapy water on the pipe joints and look for bubbles. A third solution could be to wait for a plant shutdown and listen for the turbulent flow of air leaks when everything is quiet.

The BEST solution is to ask, “do compressed air leaks produce Friction, Impacting, or Turbulence?”. That’s it! Due to the difference in pressure on either side of the compressed air line, anywhere there is a leak there is turbulent flow. Ultrasound detectors are really good at detecting turbulent flow in high noise environments. There’s no need to run your hand along the pipe, reach for the bubble solution, or wait for a shutdown. Go grab your SDT Detector and start tagging leaks today.

by Allan Rienstra - SDT Ultrasound Solutions

Reposted from ReliabilityWeb

One method of detecting vacuum leaks is to use airborne ultrasound detection, a technology already widely used for positive leak detection in compressed air systems. But finding vacuum leaks is not as straightforward as finding pressure leaks, and often times, the method is abandoned in frustration.

One problem here is the quality of the ultrasonic instrument which can vary significantly from one manufacturer to another. Lesser quality detectors cannot function well in high noise situations.  They simply have difficulty differentiating a leak sound from ambient plant noise. Since vacuum pumps already generate a lot of background noise, rarely will an inspector perform vacuum leak inspections in a quiet atmosphere.  Another problem is lack of inspector training which really plays a role when searching for vacuum leaks in high noise environments.

Just like positive pressure leaks, vacuum leaks produce a rushing, whooshing ultrasonic signal with peaks around 35-40 kHz. The ultrasound is caused by turbulent flow of air molecules at the leak site. Positive pressure leaks, such as those found in compressed air systems, push the turbulent flow outward making them easily detectable from several feet with a quality ultrasound tool. Vacuum leaks behave quite the opposite, drawing the turbulent flow inward, decreasing the distance of detection as compared with positive pressure leaks. Most of the telltale leak sound is contained within the body which means inspectors must diligently trace an entire installation leaving no stone unturned in the search for ingress.

Read the full story by Allan Rienstra – SDT International and Karl Hoffower – Failure Prevention Associates including details and photos for a Vacuum Leak Inspection on Multiple Effect Evaporator at major Pacific Northwest Pulp & Paper Mill.

by Allan Rienstra - SDT Ultrasound Solutions

For rotating machines, it is necessary to reduce friction most of the time to increase efficiency, decrease power losses and support loads. The element of choice is the well known team of bearing and lubricant. Bearings, in their different configurations, are one of the most efficient ways to reduce friction between a stationary and a rotational part of a mechanism.

Two broad classes of bearings exist: plain bearings and rolling contact bearings. Which type of bearing is used depends on several factors related to the design of the machine and its process. Sometimes both types are used in the same machine doing different jobs. For this article, the focus is on plain bearings.

Choosing the best technology to monitor friction and condition in plain bearings is a challenge. Due to the physical characteristics of plain bearings, using vibration analysis (VA) is more effective for rolling contact bearings and less so for plain bearings. Ultrasound (US) is trending more frequently for condition monitoring of rolling contact bearings and it also shows promise for plain bearings. Understanding the physical differences between the two bearing categories is critical for developing condition monitoring strategies for plain bearings using ultrasound.

Read on to find out more about plain bearing types, failure modes and how to monitor.

by Ana Maria Delgado, CRL