In This Issue:

• Up Front: Bewildered by Baseline Results

• Book Bits: Reservoir Best Practices

• Today's Tip: Dodge Disasters with Details on Dipsticks

• Q & A: Getting More Accurate With Grease

Up Front

Bewildered by Baseline Results

We recently installed a new 1-MW diesel standby generator in a large central office. In accordance with our oil sampling policy, an oil sample was taken right away to establish a baseline for this engine.

To our surprise, the results indicated very high silicon and high iron; results that appeared suspiciously like poor filtration.

Maintenance personnel quickly found the cause and stopped the accelerated wear that appeared to be taking place. Soon after a precautionary oil and filter change was accomplished, silicon and iron again tested high.

Further investigation revealed that the engine block is a sand casting and high silicon and iron are normal readings for the first 100 to 200 hours of the break-in process. (Submitted by Robin Kurth, technical support manager - Power, SBC. Thanks Robin!)

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Book Bits

Reservoir Best Practices

From "Lubrication Fundamentals".

The bottom of an oil reservoir should slope more than 1 in 25 (4 percent) toward a drain connection, which should be located at the lowest point in the reservoir. This construction promotes the concentration of water and settled impurities and permits their removal without excessive loss of oil. In addition, it permits more complete removal of flushing oil or solvents used in cleaning operations prior to startup or during an oil change. Where oil is taken directly from the reservoir for purification, it should be removed close to the low point but above the water and settled impurities. An opening or openings above the oil level, adequate for inspection and cleaning, should be provided. Large reservoirs should have an opening large enough for a person to enter. These and any other openings should have well secured, dust tight covers.

A connection should be provided at the highest point in the reservoir for ventilation. Proper ventilation results in the removal of moisture laden air and thereby reduces condensation on cooler surfaces above the oil level and subsequent rusting of these surfaces. Ventilation fixtures should be designed with air filters to prevent entrance of airborne contaminants. Instead of natural ventilation, where a source of water contamination is common - for example, large steam turbine systems - medium and large size reservoirs should be provided with a "vapor extractor," or exhauster, capable of maintaining a slight vacuum in the air space above the oil level. Too high a vacuum should be avoided, however, since it may have the effect of pulling plant atmospheric contaminants into the lubrication system.

More information about "Lubrication Fundamentals".

Today's Tip

• Label each dipstick by stamping or engraving into them the equipment identification and type of oil used to avoid possible confusion by operators or maintenance personnel. (Submitted by Russell Engelhard, U.S.Navy. Thanks Russell!)
  

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Q & A

Getting More Accurate With Grease

"How critical is the volume pumped for each stroke of a grease gun? On this site, we have a large maintenance force and many different models of grease guns. Most of our PMs are done by telling the tradesman how many shots of grease to pump. We calculated the amount per shot based on one style of grease gun using OEM or bearing calculations for total volume. How critical are these given volumes? Is it worthwhile to require the site to use one style of grease gun?"

You are right to be concerned about the variability in volumes dispensed by different grease guns. As you point out, while different models and styles of grease gun are most likely to dispense varying volumes, even nominally the same make and model of grease gun may have shot-to-shot variability.

Rather than throwing out grease guns to standardize on one type, you would likely be better-served by calibrating each gun. To do this, simply dispense 10 or 20 shots of grease from each gun and weigh how much is dispensed. Then divide by the number of shots to obtain a calibration constant for each specific grease gun.

This information can then be laminated and affixed to the gun so that whenever a PM is issued (now in ounces or grams), the lube technician can use the calibration constant for that gun to convert the prescribed grease volume in ounces on the work order, to shots based on the grease gun he or she is using.

One alternate solution may be to investigate the use of feedback tools such as ultrasonics to direct regreasing volumes rather than relying upon OEM or bearing manufacturer calculated volumes.

Mark Barnes, Senior Technical Consultant, Noria Corporation

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