Up Time Magazine- August/September 2008

Table 4 - Typical Dynamic Clearances of Rotating Equipment Component Gears Journal Bearings Pump, Gear Tooth to Side Plate/ to Case Pump, Piston Piston to Bore Valve Plate to Cylinder Pump, Vane Vane Sides Vane Tips Rolling Element Bearings Valves Directional Spool to Sleeve Proportional Spool to Sleeve Servo Spool to Sleeve Table 5 - Effect of Fluid Cleanliness on Hydraulic System Life Life Extension Factor (LEF)* A/B 26/23 25/22 24/21 23/20 Dynamic Clearances 0.1 – 1.0 microns 0.5 – 100 microns 0.5 – 5.0 microns 5.0 – 40 microns 0.5 – 5.0 microns 5.0 – 13 microns 0.5 – 1.0 microns 0.1 – 1.0 microns 2.0 – 8.0 microns 1.0 – 6.0 microns 1.0 – 4.0 microns 2x 23/21 23/19 21/18 20/17 19/16 18/15 17/14 16/13 15/12 14/11 13/10 12/9 11/8 11/81 11/82 3x 22/19 21/18 20/17 19/16 18/15 17/14 16/13 15/12 14/11 13/10 12/9 4x 21/18 20/17 19/16 18/15 17/14 16/13 15/12 14/11 13/10 12/9 11/8 5x 20/17 19/16 19/15 17/14 16/13 15/12 14/11 13/10 12/9 12/8 6x 20/17 19/15 18/14 17/13 16/12 15/11 13/11 13/9 12/8 11/8 7x 19/16 18/15 17/14 16/13 15/12 14/11 13/10 12/9 11/8 8x 19/16 18/14 17/13 16/12 14/11 14/10 13/9 12/8 9x 18/15 17/14 16/13 15/12 14/10 14/10 12/9 11/8 10x 18/15 17/14 16/13 15/11 14/10 13/10 12/8 11/8 22/19 21/18 20/17 19/16 18/15 17/14 16/13 15/12 14/11 13/10 12/9 single repair and average repairs often valued at thousands of dollars, such upgrades have always proved cost-justified. The amounts and sizes of particles can be measured with a laser particle counter. The ISO 4406 Cleanliness Rating (Table 3) reports on the particle content of 1 ml (milliliter) of oil, approximately equal to the volume of one eye dropper and Table 4 shows typical dynamic clearances of rotating equipment. Similarly, the effect of fluid cleanliness on hydraulic system 1 - Life Extension Factor 1.5 2 - Life Extension Factor 1.45 * Example: Improving the ISO 4406 cleanliness level of a hydraulic oil from 20/17 to new level of 13/11 would increase bearing life by 6 (500 percent). life can be discerned from Table 5. Concern for the size and amount of solid particles that are > 2 microns becomes evident when examining typical mechanical clearances for equipment. Contaminant particles that are larger than the mechanical clearances of lubricated components greatly accelerate wear by abrasion. Conclusion Just as water in bearing lube oil is detrimental to long-term reliable equipment operation, solid contaminants (particulates) will degrade lube effectiveness and bearing life. Experience shows that most oils are simply not clean. They may not look dirty, but they are full of small particles in the 2 to 30 micron range that the eye cannot see. These particles consist mainly of fibers, silica (dirt), and metals. It is easy to cost-justify superior means of keeping out contamination and reducing bearing distress. All that needs to be done is compare the cost of a set of superior bearing housing protector seals with the value of even one avoided equipment outage or repair event. Heinz P. Bloch (hpbloch@mchsi.com) is a professional engineer with offices in West Des Moines, Iowa. He advises process and power plants worldwide on reliability improvement and maintenance cost reduction opportunities. Heinz is the author of 17 full-length texts and over 400 papers and technical articles. His most recent texts include “A Practical Guide to Compressor Technology” (2006, John Wiley & Sons, NY, ISBN 0-471-727930-8); “Pump User’s Handbook: Life Extension,” (2006, Fairmont Publishing Company, Lilburn, ISBN 0-88173517-5) and “Machinery Uptime Improvement,” (2006, Elsevier-Butterworth-Heinemann, Stoneham, MA, ISBN 0-7506-7725-2) 28 august/september 2008 http://www.bakerinst.com http://www.bakerinst.com

Table of Contents Feed for the Digital Edition of Up Time Magazine- August/September 2008

Up Time Magazine- August/September 2008 Contents Upfront Upclose Information Technology Lubrication Infrared Maintenance Management Motor Testing Precision Maintenance Reliability Ultrasound Vibration Upgrade

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