Back to Lube-Tips™ Back Issues.

Machinery Lubrication Magazine Reliable Plant Magazine Motor Oil Selection Guide Synthetic Oil Resources

In This Issue:

• Readers Challenge: Oil Analysis Without Particle Counting?

• Today's Tip: No-mess Filter Removal

• Book Bits: Water Contamination Causes Turbine Failure

• Lube-Trivia: Name That Wear Mode

• Q & A: Quick Test for Water Demulsibility

Readers Challenge

Oil Analysis Without Particle Counting?

A large power generation company uses a central laboratory for oil analysis. It performs routine particle counts using an optical particle counter on lubricants sampled from critical equipment (compressors, hydraulics, turbine oils).

Recently the lab manager recommended that the particle counting activity be discontinued. His reason was their fluids were always clean (fewer than one percent reportable) and therefore there was no justification for spending the time and money. What would you do if you were in charge of reliability at these power plants?

Submit your answer at http://www.noria.com/challenge.asp before Tuesday, November 25, 2003. Lube-Tips editors will choose the best answer and the $100 recipient will be announced next week.

Today's Tip

No-mess Filter Removal

• This technique will help avoid a mess when changing your vehicle's oil and filter. Horizontally cut a recycled two-liter plastic pop bottle in two pieces, about halfway up. Slide either half over the loosened filter and spin the filter until it is unthreaded and drops off. Hold the cupped filter in position for a minute or two in order to catch any leakage from the filter housing before removing. I have found that it has eliminated most of the mess even on a nearly horizontally mounted filter. (Submitted by Elias Shewchuk MLT 1, Lubrication Initiatives, Tolko Manitoba Kraft Papers. Thanks Elias!)

Each tip published will earn the sender $50. Submit your tip.

Book Bits

Water Contamination Causes Turbine Failure

From "Practical Lubrication for Industrial Facilities"

For corrosion to occur, water must be present. Free water, in particular, will settle on machinery surfaces and will displace any protective surface oil film, finally corroding the surface. Emulsified water and dissolved water may vaporize due to frictional heat generated as the lube oil passes through bearings. Very often, though, the water vapors recondense in colder pockets of the lube oil systems. Once recondensed, the free water continues to work away at rusting or corroding the system.

Larger particles generated by corrosion slough off the base metal surface and tend to grind down in the various components making up the lube system, i.e. pumps, bearings, control valves, and piping. The mixing of corrosion products with free and emulsified water in the system results in sludge formation which, in turn, can cause catastrophic machinery failures. Suffice it to relate just one of many examples of water-related damage to major machinery.

When a steam turbine at a medium-sized U.S. refinery failed catastrophically, the initial problem was attributed to coupling distress and severe unbalance vibration. When the coupling bolts sheared, the steam turbine was instantly unloaded and the resulting over-speed condition activated a solenoid dump valve. Although the oil-pressurized side of the trip piston was thus rapidly depressurized, the piston stem refused to move and the turbine rotor sped up and disintegrated. The root cause of the failure to trip was found to be water contamination of the turbine control oil. Corrosion products had lodged in the trip cylinder and, although enveloped in control oil, the compression spring pushing on the trip piston had been weakened by the presence of water.

More information about the book "Practical Lubrication for Industrial Facilities"

Lube-Trivia

Name That Wear Mode

Test your knowledge and prepare for ICML lubrication and oil analysis certification with Lube-Trivia.

QUESTION: What is the name of the wear mode associated with scratch marking from particle contamination?

For the answer, visit: http://www.lube-tips.com/trivia/20031119.asp

Q & A

Quick Test for Water Demulsibility

"How do I check to see if my aged hydraulic and/or lubricating oils can still shed water effectively?"

This is an issue of demulsibility, which is the measure of an oil's ability to release water. Of course, if you have time, your lab can run a specific test (ASTM D1401) to measure the remaining demulsibility potential.

For a quick Pass/Fail test, measure an equal amount new lubricant and water (1 pint each), and fill a blender. Heat to 100 degrees F (38 degrees Celsius), or whatever temperature closely resembles the operating temperature of the sump. Thoroughly mix the oil with the water. Measure the amount of time it takes to separate. Also measure how much of the mixture does not separate (the emulsion is called the "cuff"). Now repeat the test with the aged lubricant.

If it takes more than 20 percent longer to separate, then consider having a lab run the test according to the lab procedure. If the results indicate that the demulsibility capacity is diminished, then consider how to best address the problem, particularly if the sump is prone to moisture contamination.

Submit your question here.

Please Forward This Issue to a Friend

If you haven't already done so, please forward this issue to one or two of your friends or business associates. Thanks so much!