ASTM D7718 Sampling Standard (topic presented at OilDoc2015)
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Transcript of ASTM D7718 Sampling Standard (topic presented at OilDoc2015)
Lubricant Sampling
• Oil analysis using valves and gravity
• Drop tube sampling
• Retrofit sampling mini-mess
• Importance of sample location
• Drop tube point of sample uncertain
Image from Noria Corporation
Grease Sampling
• Historically during disassembly following failure
• Using “popsicle stick”, screwdriver, cable ties
• Samples only available near access points, ports
• “Grab Sample” has similar limitations to “Drop Tube Sampling”
• ASTM Grease subcommittee initiates working group to develop sampling standard, 2009
• Projects initiated in USA and Denmark to test effectiveness of grease sampling in 2010, 2012
Motor Operated Valves (MOV)
• EPRI method using plastic tubing at gears
• Grease removed and visually inspected
• Kits made utilizing known consistency greases for comparison to obtained sample
• Questionable samples; very subjective analysis
Photos: Bolt, et. al. Machinery Lubrication Magazine. May 2003
Grease sampling devices
• Maintain purge function with little/no backpressure when threaded into machine
• Can be attached to T-handle for precise sample location adjacent to internal gears
• Design to optimize the analysis process
Sampling Techniques
• MOV Gearbox
1 2 3 4 5
• Electric Motor Bearing
1 2 3 4 5
• Pillow Block Bearing
1 2 3 4
MOV Test Stand-EPRI Project
•Actuators filled with in-service grease
•Cycled forward and backward
•Produced video of grease flow
•Data on consistency of wear levels
Wear monitoring
• Hall effect sensor counts total ferrous debris level of sample, not the variable amount through the body of grease
Method AverageStandard
Deviation
Relative Standard
Deviation
fdM+ 277 ppm 7 2.53
DR- 205 46 22.44
RDE 57 ppm 16 28.07
Method AverageStandard
Deviation
Relative Standard
Deviation
fdM+ 277 ppm 7 2.53
DR- 205 46 22.44
RDE 57 ppm 16 28.07
Wind Turbine grease sampling and analysis
• 2-year project conducted with DONG Energy and Vattenfall, two largest offshore wind operators in the world
• Dr. Kim Esbensen, internationally recognized expert in Theory of Sampling (TOS), Denmark
• Rich Wurzbach, MRG Labs, inventor of Grease Thief
• Systematic evaluation of grease heterogeneity, sampling methodology, and analysis validity and repeatability for wind turbine main bearings in on-shore and off-shore applications
• Results published at OilDoc, LUBMAT, and AWEA
Richard Wurzbach– OilDoc Conference 2015
Wind Main Bearing Sampling
• Grease flow dependent on temperature, bearing movement
• Grease Thief & T-handle used to capture flowing grease
• Revised T-handle developed for Denmark Off-shore Wind Research Project
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ASTM Standard Development
• Incorporation of grease sampling research
• Inclusion of historical methods for sampling with considerations and limitations
• Failed component sampling, care in obtaining sample or multiple samples
• Use of tubing, adequacy of suction alone, possibility of peripheral grease sampling
• Inclusion of new technologies for active and passive sampling
Richard Wurzbach– OilDoc Conference 2015
Scope and Terminology (ASTM D7718)
• Inservice grease samples, various components
• Requirements for multiple samples
• “Passive” and “Active” sampling
• “Actuate” to take core samples
• Hazards and Cautions
Active Grease-Sampling Device (shown as Fig. 1 in ASTM D7718)Passive Grease-Sampling Device (shown as Fig. 3 in ASTM D7718)
General Procedures (ASTM D7718)
• cleanliness of sampling tools
• homogeneity of samples
• uniformity and design of the sampling devices
• operator training and knowledge of equipment being
• shipping considerations and sample labelling
• containers and protective sleeves to prevent leakage and co-mixing of samples
Active Sampling• Introducing a device to the surface or inside of a
machine
• “Stinger probe” allows for the positioning of the device adjacent to target surface
• Use of an extending handle to reach set depth within machine
• Use of tubing to extract sample, possibly with suction
• Use of spatula or soft tool to extract from accessible surface (pillow block, open gear)
Active Sampling
• T-handle Coring with active or passive sampler
• Spatula and syringe on pillow block
• Syringe and tubine on slewing bearing
“Taking a sample” from Rothe Erde “Grease Sampling Set” instructions
Passive Sampling• Threaded or attached to machine
• Normal or initiated purging of reservoir displaces into sampler
• Must have provision for proper purge; overgreasing must be
avoided
• Sample prevents
contamination from
surroundings during
purge
Failure Analysis
• Proper handling of specimen
• Separation of external dirt/debris
• Removal of shields and seals
• Extraction of grease sample; need for multiple samples
• Correlation to observed conditions, history and metallurgy
Cautions and Concerns
• Use of plastic tubing may not properly suction all representative grease, point of sampling may vary, as in oil “drop-tube” sampling
• Samples must be taken from “live-zone” in the machine, understanding of flow dynamics important
• Sample must be properly labeled and protected during shipment
• Quantity must be sufficient for required tests
Acceptance and Use
• D7718 is basis for AWEA Recommended Practices for wind turbine sampling– 812 Grease Sampling - Main Bearing– 813 Grease Sampling - Generator Bearing– 814 Grease Sampling - Pitch Bearing– 815 Grease Analysis
• Used by largest operators in Danish Offshore Wind industry• Published by US Nuclear Industry in “Effective Grease Practices” NMAC Guideline• Analysis utilized by labs in Europe, Asia, North America
• Sampling kits used on six continents around the globe
Next Steps• Development of ASTM Standard for Grease Analysis
– Integrated Tester section of ASTM with a balloted Work Item
–Currently in Interlaboratory Study (ILS) in US labs for precision statement
– Laboratories in Asia, Europe and North America to participate in development of methods
• Development of “Slim” version of sampler to access rail locomotive wheel bearings, wind bearings
• Mini-lab development for “In-Sampler” Analysis, including ferrous debris, colorimetry
• Real-time particle counting in grease processed between two samplers
• Major lubricant manufacturers worldwide utilizing for support of customer base
Analysis Techniques
Sample is received. fdM+ is runDie extrusion is performed and substrate is made
Two strips are used to make
a dilution to run RDE/ICP.
One Strip is used
for FT-IR.
One Strip is Dissolved in Green
RULER solution to run RULER.
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Optical Spectroscopy
•Optical spectroscopy quantifies the appearance of grease
•Grease aging, contaminants, mixtures, chemometrics
27
Trends of moisture in bearings
0
100
200
300
400
500
600
700
800
900
Mo
istu
re, p
pm
314 Front
314 Rear
319 Front
319 Rear
Grease type: SKF LGWM1
• Thickener: Li
• Base oil: Mineral oil
• Viscosity @ 40C: 200 cSt
• NLGI-class: 1