Oil analysis 02 2005

Vibration Institute Piedmont Chapter 14 Barry Schoch PREDICT Ferrography / Used Oil Analysis February 25, 2005 Phone 800-543-8786 www.predictusa.com “First Sample in your Trend” What your Lab can and cannot tell you Why Do Ferrography / UOA? To Identify Abnormal Wear Conditions Before They Become Significant Enough To Adversely Effect Component Life Used Lubricant Analysis Trends the physical properties of the lubricant Determines the chemical breakdown or contamination of the fluid Determines the concentration of dissolved elements & additives UOA Tests • • Oil Bath RDE Spectrometer  Viscosity  Elemental Concentration • FTIR Spectrometer • Titration – TAN & TBN  Oxidation, Nitrates, Sulfates, Water, Fuel, Glycol, Additive Degradation •  Acid & Base Level Trends Water – Crackle – Karl Fischer  Concentrations to 800ppm  Concentrations to 10ppm • Particle Count  NAS & ISO Cleanliness Ratings • • Gas Chromatography Flash Point  Fuel Dilution Observations • Large particles in sample – Likely to settle in sample bottle – Particles over 80 microns are easily visible to naked eye Observations • Crackle Test – Hot Plate set at 115-125C – Sensitive to between 800 and 1000 ppm depending on oil viscosity and additives Viscosity ASTM D-445 Constant Temp Oil Bath 40oC or 100oC Nametre Oscillation Viscometer Non-ASTM Test Ambient Temp • Measure of shear rate vs shear stress; i.e resistance to flow • Measured at constant temperature (40oC or 100oC) Emissions Spectrometer (ELEMENTAL SPECTROSCOPY) EXCITATION SOURCE ICP LIGHT EMISSIONS AA RDE DIFFRACTION GRATING DETECTORS SIGNAL PROCESSING FT-IR: Used Mineral Oil Spectrum Wear • Results from ordinary wear or equipment damage • Missing volume goes into the lube system in the form of fine particles • Wear is generated initially as small particles over time, not large chunks Wear • Since most of the wear debris is some form of steel, a magnetic field is used for separation • Debris is so small that a high gradient field rather than a steady field is required • Larger particles are affected more strongly than smaller ones, so a rough separation according to size is possible DR Ferrograph • Uses optics to determine concentration of wear debris • Is able to evaluate concentrations of magnetically attracted wear debris • Particle size limitation is 300 microns • Effective trending tool for most types of industrial equipment • Limitations are for extremely clean lube systems, i.e, hydraulics, some turbines DR Acceptance Limits WEAR PARTICLE CONCEN ACCEPTANCE LIMITS Vacuum Pumps WPC = 1-5 Boiler Feed Pumps WPC = 1-100 Gas Compressors WPC = 1-50 Turbines Fans Journal Bearings WPC = 1-20 Roller Bearings WPC = 5-100 Engines WPC = 10-150 Transmissions Extruder Gearboxes WPC = 100-600 Dragline Gearboxes WPC = 1,000-50,000 Hoist Gearboxes Analytical Ferrography • View slide made by FM • Several magnifications –Speed –Detail • Identify debris using –Reflected light –Transmitted light –Polarized light –Color filtered light BEARING WEAR Copper Alloy Steel Prior to Heat Treatment Low Alloy Steel Lead/Tin Babbitt Metal Analytical Ferrography Particle Classification •Size •Shape •Concentration •Composition Analytical Ferrography Rating Rating Rating Rating Rating Rating Rating Rating Rating Rating 10 Analytical Ferrography Correlation w/ DR Ferrograph WPC=10 WPC=50 WPC=100 WPC=500 WPC=1000 Equipment Condition Report Equipment Condition Report (cont) Summary First Sample Analysis Yes No • Detect Dissolved up to 8µm Particles • Problems detecting Onset of Abnormal Wear • Determine Lubricant Additive Depletion • Determining Sources of Wear (bearings, gears, seals, rings, etc.) • Detect Fluid Contamination • Determine Lube Physical • Reliable Estimate of Machine Wear Condition First Sample Analysis • Observation i.e., water, large particles • Viscosity Yes Yes • RDE Spectroscopy (21 metals) Limited w/ Ref First Sample Analysis • FT-IR Spectroscopy No • Water by Karl Fischer Titration Yes • TAN, TBN No • DR Ferrograph Limited • Analytical Ferrography Yes Questions ... at 115-125C – Sensitive to between 800 and 1000 ppm depending on oil viscosity and additives Viscosity ASTM D-445 Constant Temp Oil Bath 40oC or 100oC Nametre Oscillation Viscometer Non-ASTM Test... Machine Wear Condition First Sample Analysis • Observation i.e., water, large particles • Viscosity Yes Yes • RDE Spectroscopy (21 metals) Limited w/ Ref First Sample Analysis • FT-IR Spectroscopy... Conditions Before They Become Significant Enough To Adversely Effect Component Life Used Lubricant Analysis Trends the physical properties of the lubricant Determines the chemical breakdown or contamination