Are you Listening to the Heartbeat of your Equipment?

June 19, 2018

In most cases, when equipment is in failure mode, it begins to make sounds that are not commonly heard during normal operation conditions. Once this sound is heard a defect (at least one) is already present in the equipment.

Using our vibration tools can assist in detecting the defect before that sound is heard with the naked ear.

Think of a vibration sensor as a stethoscope that allows a vibration instrument to listen to the heartbeat of the equipment. The heartbeat is then recorded and data can be viewed historically for that equipment. The data can then be compared to other readings collected on the equipment to quickly see if any changes have occurred.

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3 Practical Tips for Ultrasound Leak Detection

June 12, 2018

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!

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Three Things That Kill Your Reliability And What You Can Do About Them Now

June 5, 2018

As Published by Solutions Magazine March/April 2018 issue

Ana Maria Delgado, CRL
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.

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Machine Life Expectancy – What Should the Maintenance Organization Focus on?

May 29, 2018

Guest post by John Lambert at Benchmark PDM

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.

Fig 1. The P to F Interval Curve.

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.

Fig 2. You may see the P to F curve compartmentalized like this one (see sections below). However, the whole curve is the life expectancy of the machine and we monitor it using Condition Based Maintenance techniques.

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.

Fig 3. The most important part of the life expectancy of a machine is the design and installation of the machine.

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?

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6 Signs your Lubrication Program is on Track

May 22, 2018

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.

 

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