Useful Predictive Maintenance Technologies for Manufacturing Facilities

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Useful Predictive Maintenance Technologies
for Manufacturing Facilities
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• Predictive Maintenance or PdM is defined as
  efforts that are designed to detect the onset of
  a means of degradation with the goal of
  correcting the degradation prior to significant
  deterioration of the equipment or component.
• Simplified, PdM is an effort to find problems and
  correct them before something catastrophically
  fails, and removes a facility, machine or
  production line from effective operation.

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• The diagnostic capabilities of Predictive
  Maintenance Technologies have increased in recent
  years, largely due to new sensor advancements. I
  have been in the Predictive/Preventive
  maintenance business for almost 30 years. The
  innovation and enhancement of PdM/Reliability
  practices has truly been a continual improvement
  process.

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• Any truly effective PdM effort utilizes Vibration
  Analysis as the cornerstone of the program.
  Vibration Analysis is paramount to such an
  effort.
• However, the challenges of implementing a
  successful facility-wide Vibration Analysis
  program are numerous.

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• Cost vs. perceived benefit
• Lack of understanding of the technology
• It is not a go/no go technology, and requires a
  well trained analyst to be effective
• Lack of management buy-in
• Lack of training if attempted in-house
• Maintenance resists being proactive and remains
  in a comfort zone of fighting fires

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• And the list continues. But lets move beyond
  Vibration Analysis and discuss some of the other
  PdM technologies, and diagnostic tools that could
  be of immediate, if not extreme value to your
  facility.

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• The Predictive Maintenance Technologies for
  discussion today are
• Infrared Thermography
• Ultrasonic Scans
• Oil Analysis

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Infrared Thermography

• Infrared (IR) Thermography is the process of
  generating visual images that represent
  variations in IR radiance of the surfaces of
  objects. This IR radiance of the object is
  proportional to its existing temperature. This is
  accomplished with an Infrared Imager (camera).

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• The principal value of this type of inspection
  deals with In-Plant Electrical Systems and
  components. Electrical problems are known to be a
  fire hazard and many Facility Insurance providers
  demand proof of IR electrical testing scans or
  give a discount for providing such evidence.
• IR scans are successful in identifying problems
  with electrical, mechanical, process, roof,
  insulation, and sometimes moisture issues.

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Infrared Thermography Case Studies

• The following picture shows a fuse block with
  three 100 amp 600 volt fuses.
• To the naked eye all seems fine.

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• The Infared Thermography Scan tells a completely
  different story. The top clamp on the third fuse
  was very loose with a temperature of almost 300
  degrees! Fire hazard? Failure waiting to happen?
  Probably both.
• This is a disconnect for an industrial fan. The
  fan was temporarily idled, locked out and a
  qualified Electrician repaired the clip.
  Afterwards this same scan had temperature
  readings that were no greater than 98 degrees.

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• This is a photo of a motor and pump combination
  in a manufacturing facility. Again to the naked
  eye there does not seem to be a problem. It is
  very doubtful that a Mechanic or an Electrician
  walking by on a PM would suspect a problem.

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• However the IR scan shows that the motor was
  running at an elevated temperature of over 200
  degrees. This temperature is detrimental to the
  insulation, the iron, the windings and the grease
  in the bearings.
• The motor was shutdown and a redundant pump that
  was put into service. During the motor rebuild
  the motor repair shop said that the motor had
  been pumped full of grease. The added value
  here was that the plants lubrication program was
  amended to assure that this did not happen again.

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Ultrasonic Inspections

• Ultrasonic or ultrasounds are sound waves that
  have a frequency of greater than 20 kHz. These
  frequencies are not perceived by the human ear.
  Non-contact Ultrasonic Detectors are utilized in
  PdM to detect airborne ultrasound. Contact probes
  are used for diagnostics with bearings, steam
  traps, etc.

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Ultrasonic detectors are useful in identifying
problems in

• Compressed gas (air) leaks
• Compressed fluid leaks
• Vacuum leaks
• Steam trap failures
• Bearing condition monitoring
• Electrical arcing/tracking or corona testing

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• Lets focus on Compressed Air leaks, as this is
  the proverbial low-hanging fruit in most
  facilities.
• Compressors that generate compressed air for a
  facilitys demand are inherently expensive to own
  and expensive to operate. They are a major source
  of the Electricity costs associated with
  operating most facilities. If there are leaks in
  the compressed air system, the compressor is
  operating, degrading, and utilizing electricity
  while providing no value to the facility. The
  leaking air is simply a source of cost to the
  facility, both immediately and in the future.

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• I have never heard of a single compressed air
  leak survey that resulted in finding zero air
  leaks. On the contrary a typical survey will
  identify dozens of sources of leaks and at times
  that number is greater than one hundred. Some
  facilities are acutely aware of this and have
  their compressed air system surveyed several
  times a year. Due to the inherent cost/benefit
  ratio, it is my opinion that an annual survey
  should be a minimum.

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Compressed Air Leak Case Studies

• A manufacturing Plant in the southeast had two
  compressors at the plant site. Both compressors
  were continually operating. Plant management had
  assumed that there was then a need for a third
  compressor and had budgeted capital dollars to
  install a third unit. Before the purchase and
  installation of the third compressor, a
  Compressed Air Leak Survey was performed in the
  plant. This survey identified 107 air leaks that
  were tagged for repair.

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• Subsequent to the repair of the tagged leaks the
  two existing compressors were capable of handling
  the needs of the plant with capacity to spare,
  and only one compressor was operating for much of
  the day. Calculated at .05/kilowatt/hour to
  operate the compressors, and the fact that the
  plant operated 24 hours a day it is estimated
  that the Energy savings were over 70,000.00 per
  year. That savings is in addition to the fact
  that they did not have to spend the capital
  dollars to buy, install, and operate another
  compressor .

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• This is a real example, folks. It may be an
  extreme example, but true. Lets look at an
  example from another senario.
• Lets assume that all the air leaks in your
  facility combined equate to an opening of 1/4.
  Thats all of the cracked tubing, all of the
  loose fittings, all of the threaded connections
  that are leaking-by, etc.
• Lets also say for this example that the facility
  only operates 8 hours a day, 5 days a week.

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• That 1/4 total air loss would result in
  2,000.00 in Energy savings per year _at_ 8/5
  operation.
• If the plant is operating 24/7 the estimated
  savings would be 8,000.00 annually.
• So, is this Low Hanging Fruit? No machinery to
  replace, no energized components to work on, no
  hot work permit, just some fittings, sealing,
  tubing replacement, etc. Rudimentary maintenance,
  if they know what to fix.

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Oil Analysis

• Oil Analysis or Tribology is one of the oldest
  PdM technologies that is still used today. It
  dates back to just after World War II and was
  first utilized by the railroad industry to
  monitor the health of diesel engines in
  locomotives.
• Oil Analysis is used to determine three basic
  machine conditions relating to the machines
  lubrication or its lubrication system.

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• The first condition is that of the oil. That is,
  will its current condition lubricate as per
  design? This is determined by the viscosity of
  the oil.
• The second is the condition of the machine
  itself. By analyzing wear particles present in
  the lubricant, machine wear can be evaluated and
  quantified.

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• The third is assessing the lubrication mechanism
  itself. Have the physical boundaries of the
  lubricant been compromised or contaminated? Water
  is the main culprit, but other contaminates could
  be intrusive depending on the operating
  environment.

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• Oil analysis is most often an outsourced
  function. Oil Analysis Labs typically provide oil
  sample bottles and labels with mailing
  instructions that the plant utilizes to gather
  and ship the oil samples.
• Oil analysis is performed on machines and
  components such as

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• Oil lubricated motor/pump/fan bearings
• Antifriction (sleeve) bearings
• Oil lubricated Ball Bearings
• Oil Lubricated Roller Bearings
• Gearboxes
• Hydraulics
• Any system where the condition of the oil is
  directly related to decreased equipment wear,
  longer lubricant life, or improved equipment
  reliability

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• Oil analysis is another potential for a good
  return on the investment. Oil samples are
  typically analyzed for 30 to 100 per sample
  depending on the level of analysis required. Most
  facilities are effectively supported with the
  lower end of this analysis range.
• The costs are high when machinery and components
  fail. Equipment replacement cost, labor cost, the
  lead time in acquiring replacements and
  downtime/loss of production associated with a
  bearing or gearbox failure can be tremendous.

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Oil Analysis Case Histories

• Oil Analysis was performed on a large electric
  motor with antifriction or sleeve bearings. The
  oil analysis showed that wear particles as large
  as 30 microns were suspended in the oil sample.
  The bearings were flushed and new oil was added.
• Also, a new set of bearings were acquired due to
  the oil sample analysis and report.

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• Several weeks later the motor was scheduled for
  downtime. The existing bearings were rolled out.
  There was visible damage in the babbitt of each
  of the plain bearings.
• The new bearings in-hand were installed and the
  plant averted a shutdown due to a bearing
  failure.

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Oil Analysis Case Histories

• An oil lubricated Cooling Tower gearbox was found
  to have a breakdown in the lubricating properties
  of the oil as well as being contaminated with
  water.
• Due to the Oil Analysis report, further
  inspection of the gearbox was performed. This
  effort revealed a damaged seal that was allowing
  the intrusion of water.

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• The seal was replaced and the gearbox was spared
  an untimely death as the water would have
  continued to invade if the oil analysis had not
  lead to the mechanical inspection of the gearbox.

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In Conclusion

• I began this discussion with useful. Maybe
  cost-effective or of-value would be better
  descriptions for this discussion, but the fact
  remains that some Predictive Maintenance
  applications may be difficult to quantify in
  regards to the return on your investment.

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• Vibration Analysis, being the foundation of
  Equipment Reliability Based Technology is
  certainly useful and of extreme value if managed
  properly.
• However, it is but one of several tools to help
  keep plants from unscheduled downtime as well as
  in capturing cost savings. And maybe the costs
  savings from some of the other PdM Technologies
  discussed today could help justify a Vibration
  Analysis Program! ?

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• J. Scott Glover, President
• The ADVANCED Team, Inc.
• 126 Periwinkle Lane
• Mooresville, NC 28117
• 800-732-2890 toll-free
• 704-528-3628 fax
• scott_at_theADVANCEDteam.com