| 1. Advice for Problem Heat Exchangers 2. Eight Causes of Bearing Failures
3. Alkaline Additives for Diesel Engines 4. How to Get Better Oil Analysis Results
| Today's Tip: Advice for Problem Heat Exchangers |
There are many reducers in an industrial environment that require heat exchangers. Along with the benefits of heat exchangers
comes the possibility of water leaks. Determine if the heat exchanger is truly necessary by noting the temperature of the reducer when the heat exchanger is valved off. If the reducer temperature is below the oil's highest temperature
runability, it may be a good idea to valve off the water to deter a possible water leak. If the reducer can't operate without the heat exchanger, then oil analysis should be performed
more frequently. It is important to frequently perform oil analysis on water-cooled equipment because a leak in the cooling system can be catastrophic to the equipment. (Submitted by
Hack Hensley, Predictive Maintenance, Mitsubishi Polyester Film. Thanks Hack.) Join us in New Orleans, LA for Oil
Analysis I & II training on Nov. 15-18. Followed by ICML MLA certification testing.
Each tip published will earn the sender $100. Submit
your tip.
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| Book Bits: Eight Causes of Bearing Failures |
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From "Machinery Failure Analysis and Troubleshooting"
The calculated life expectancy of any bearing is based on the assumption that good lubrication in proper quantity will always be available to that
bearing, that the bearing will be mounted without damage, that dimensions of parts related to the bearing will be correct, and that there are no defects inherent in the bearing. However, even when properly applied and
maintained, the bearing will still be subjected to one cause of failure: fatigue of the bearing material. Fatigue is the result of sheer stresses cyclically applied immediately below the load-carrying surfaces and is observed as
spalling away of surface metal. However, material fatigue is not the only cause of spalling. There are causes of premature spalling. So, although the observer can identify spalling, he must be able to discern between
spalling produced at the normal end of a bearing’s useful life and that triggered by causes found in three major classifications of premature spalling: lubrication, mechanical damage and material defects. Most bearing
failures can be attributed to one or more of the following causes: 1. Defective bearing seats on shafts and in housings
2. Misalignment
3. Faulty mounting practice
4. Incorrect shaft and housing fit
5. Inadequate lubrication
6. Ineffective sealing
7. Vibration while the bearing is not rotating
8. Passage of electric current through the bearing
More information about the book "Machinery Failure Analysis and Troubleshooting"
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Contamination control
for mobile equipment. The new Des-Case® Disposable Steel Breather is the ideal desiccant breather for mobile equipment. With 1-micron filtration and a rugged metal
housing, the DC-DS breather is durable, resistant to vibration, and can withstand high temperatures. The unit is available with several adapter options, including a proprietary design feature for
extreme humidity and high outflow applications, which creates a virtually sealed system. By prohibiting entry of dirt and moisture, mobile equipment operators can attain significant cost
reductions. Not only from extended oil drain intervals, but through prevention of premature component failure and by limiting rebuilds. www.des-case.com/DCDS_tech.pdf
E-mail: breathe@des-case.com |
| Lube Trivia: Alkaline Additives for Diesel Engines |
Test your knowledge and prepare for ICML
lubrication and oil analysis certification. QUESTION: Why are diesel engine oils compounded with alkaline additives and what is the function of the additive to which it is introduced?
Get the answer. |
| Q & A: How to Get Better Oil Analysis Results |
"We have a quarterly oil sampling program at our mill on many of our critical systems. We have installed sampling ports on our hydraulic and oil circulation systems but rarely see an advance warning of equipment problems.
Consequently, we have experienced unexpected failures on sampled systems. What can we do to improve our results?"
There are many factors that can influence the effectiveness
of an oil analysis program, including test slate selection, alarm levels, laboratory quality, sample frequency, sample location and equipment operational factors to name a few. Two common problems that programs encounter
include poor test selection and poorly selected sample port locations.
While both of these can confuse the outcome and minimize the effectiveness of analysis, a properly
selected sample location is vital for trending changing equipment condition. It is possible to review lubricant and contamination conditions with samples taken from many locations in most reservoirs. However, sampling
for evidence of mechanical problems requires a sample to be collected from a location that contains the highest concentration of 'evidence' of a problem. The evidence is of course the wear metals.
Samples are often collected from a pressure line after a filter, or from a drain line toward the floor of a reservoir. This is generally because these locations enable easy installation and access. However,
these common locations are far from ideal because the 'evidence' may be filtered or settled out of the lubricant, leaving the program with little more than fluid properties information. Sample ports must be configured to enable
collection of lubricant in close proximity to the mechanical components in question. We have heard the axiom about factors influencing real estate transactions: The top three factors in maximizing
real estate value are Location, Location and Location. The same concept applies to oil analysis-based equipment condition monitoring programs. Submit a question | Discuss
on Message Boards |
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