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Pocket Book Equipment Life Expectancy Factors 2 Sources of Contamination The Micrometre "µm" A study by Dr. E Rabinowicz at M.I.T. observed that 70% of component replacements or 'loss of usefulness' is due to surface degradation. In hydraulic and lubricating systems, 20% of these replacements result from corrosion with 50% resulting from mechanical wear. Presented at the American Society of Lubrication Engineers, Bearing Workshop, 1981. LOSS OF USEFULNESS OBSOLESCENCE (15%) ACCIDENTS (15%) SURFACE DEGRADATION (70%) MECHANICAL WEAR (50%) CORROSION (20%) ABRASION ADHESIONFATIGUE Built in contaminants from components: • Cylinders, fluids, hydraulic motors, hoses and pipes, pumps, reservoirs, valves, etc. Generated contaminants: • Assembly of system • Operation of system • Break-in of system • Fluid breakdown 'Micron' = micrometre = µm 1 micron = 0.001 mm (0.000039 inch) 10 micron = 0.01 mm (0.0004 inch) Smallest dot you can see with the naked eye = 40 µm Thickness of a sheet of looseleaf note paper = 75 µm The micrometre is the standard for measuring particulate contaminants in lubricating and fluid power systems. External ingression: • Reservoir breathing • Cylinder rod seals • Bearing seals • Component seals Contaminants introduced during maintenance: • Disassembly/assembly • Make-up oil Human hair (75 µm), particles (10 µm) at 100x (14 µm/division) Relevant Filtration & Contamination Standards ISO 2941 Filter elements - verification of collapse/burst pressure rating ISO 2942 Filter elements - verification of fabrication integrity and determination of the first bubble point ISO 2943 Filter elements - verification of material compatibility with fluids ISO 3722 Fluid sample containers - qualifying and controlling cleaning methods ISO 3724 Filter elements - determination of resistance to flow fatigue using particulate contaminant ISO 3968 Filters - Evaluation of differential pressure versus flow characteristics ISO 4021 Extraction of fluid samples from lines of an operating system ISO 4405 Determination of particulate contamination level by the gravimetric method ISO 4406 Method for coding the level of contamination by solid particles ISO 4407 Determination of particulate contamination by the counting method using an optical microscope ISO 10949 Guidelines for achieving and controlling cleanliness of components from manufacture to installation ISO 11170 Filter Elements - sequence of tests for verifying performance characteristics ISO 11171 Calibration of automatic particle counters for liquids ISO 11500 Determination of particulate contamination by automatic particle counting using the light extinction principle ISO 11943 Methods for calibration and validation of on-line automatic particle-counting systems ISO 16889 Filter elements - Multi-pass method for evaluating filtration performance of a filter element ISO 18413 Component cleanliness - Inspection document and principles related to contaminant collection, analysis and data reporting ISO 23181 Filter elements - determination of resistance to flow fatigue using high viscosity fluids SAE ARP4205 Filter elements - method for evaluating dynamic efficiency with cyclic flow 3 Fluid Analysis Methods for Particulate Method Units Benefits Limitations Optical Particle Number/mL Provides size Sample Count distribution. preparation unaffected by fluid time opacity, water and air in fluid sample Automatic Particle Number/mL Fast and Sensitive to ‘silts’, Count repeatable water, air and gels Patch test Visual comparison/ Rapid analysis of Provides and fluid cleanliness code systems fluid approximate contamination cleanliness levels contamination comparator in field. Helps to levels identify types of contamination Ferrography Scaled number of Provides basic Low detection large/small information on efficiency on non- particles ferrous and magnetic particles magnetic particles e.g. brass, silica Spectrometry PPM Identifies and Cannot size quantifies contaminants; contaminant limited above 5 µm material Gravimetric mg/L Indicates total Cannot distinguish mass of particle size. contaminant Not suitable for moderate to clean fluids. i.e. ISO 18/16/13 4 5 N um be r O f P ar tic le s G re at er T ha n S iz e P er M ill ili tr e 0.4 0.5 1.0 1.5 2.0 3.0 4.0 5.0 10 15 20 30 40 50 100 150 200 300 400 500 1,000 1,500 2,000 3,000 4,000 5,000 10,000 15,000 20,000 *Range Code Microscope particle sizes, μm2 5 15 APC particle sizes, μm (c)4 6 14 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 . 20,000 10,000 5,000 2,500 1,300 640 320 160 80 40 20 10 5 2.5 1.3 6 4 µm(c) 430 16 6 µm(c) 90 14 14 µm(c) 22 12 (c) designates 'certified calibration per ISO 11171, traceable to NIST Understanding the ISO Cleanliness Code Particle Count Summary * Note: each increase in range number represents a doubling of the contamination level. The ISO code references the number of particles greater than 4, 6 and 14 µm(c) in one millilitre of sample fluid. To determine the ISO Cleanliness code for a fluid, the results of particle counting are plotted on a graph. The corresponding range code, shown at the right of the graph, gives the cleanliness code number for each of the three particle sizes. Particle count per mL greater than size code ISO 4406 Range code 6 Sample Volume: 100 mL Magnification: 100x Scale: 1 division = 10 µm Particle Count Summary Size Particle Count ISO NAS1638 Range per mL 4406 (SAE Code AS4059) >4 µm(c) 160 - 320 15 6 >6 µm(c) 80 - 160 14 6 >14 µm(c) 20 - 40 12 6 Photo Analysis Little contamination is present. The visible contamination is silica. Sample Volume: 100 mL Magnification: 100x Scale: 1 division = 10 µm Particle Count Summary Size Particle Count ISO NAS1638 Range per mL 4406 (SAE Code AS4059) >4 µm(c) 40 - 80 13 4 >6 µm(c) 20 - 40 12 4 >14 µm(c) 5 - 10 10 4 Photo Analysis Very little contamination is present. The visible particle is silica. ISO 4406 Cleanliness Code 15/14/12 ISO 4406 Cleanliness Code 13/12/10 7 Sample Volume: 100 mL Magnification: 100x Scale: 1 division = 10 µm Particle Count Summary Size Particle Count ISO NAS1638 Range per mL 4406 (SAE Code AS4059) >4 µm(c) 5,000 - 10,000 20 10 >6 µm(c) 640 - 1,300 17 9 >14 µm(c) 160 - 320 15 9 Photo Analysis Little contamination is present. The visible contamination is silica and black metal. Sample Volume: 100 mL Magnification: 100x Scale: 1 division = 10 µm Particle Count Summary Size Particle Count ISO NAS1638 Range per mL 4406 (SAE Code AS4059) >4 µm(c) 640 - 1,300 17 7 >6 µm(c) 160 - 320 15 7 >14 µm(c) 40 - 80 13 7 Photo Analysis Very little contamination is present. The visible particle is black metal. ISO 4406 Cleanliness Code 20/17/15 ISO 4406 Cleanliness Code 17/15/13 8 Sample Volume: 100 mL Magnification: 100x Scale: 1 division = 10 µm Particle Count Summary Size Particle Count ISO NAS1638 Range per mL 4406 (SAE Code AS4059) >4 µm(c) 10,000 - 20,000 21 12 >6 µm(c) 5,000 - 10,000 20 12 >14 µm(c) 1,300 - 2,500 18 12 Photo Analysis The visible contamination is mainly silica with some metallic and rust particles. Sample Volume: 100 mL Magnification: 100x Scale: 1 division = 10 µm Particle Count Summary Size Particle Count ISO NAS1638 Range per mL 4406 (SAE Code AS4059) >4 µm(c) 5,000 - 10,000 20 11 >6 µm(c) 2,500 - 5,000 19 11 >14 µm(c) 640 - 1,300 16 11 Photo Analysis The visible contamination is mainly silica with some metallic and rust particles. ISO 4406 Cleanliness Code 21/20/18 ISO 4406 Cleanliness Code 20/19/16 9 Silica Hard, translucent particles often associated with atmospheric and environmental contamination, e.g., sand, dust. Types of Contamination Bright Metal Shiny metallic particles, usually silver or gold in colour, generated within the system. Generated contaminants are products of wear and often cause additional component wear and accelerated fluid breakdown. Black Metal Oxidized ferrous metal inherent in most hydraulic and lubricating systems; built-in contaminant and genereated within the system by wear. Rust Dull orange/brown particles often seen in oil from systems where water may be present, e.g., oil storage tanks. Fibers Contaminants most commonly generated from paper and fabrics, e.g., shop rags. Magnification: 100x Scale: 1 Division = 10 µm Cake of Fines Very large concentrations of ‘silt’-size particles coat the analysis membrane and build-up into a cake. The cake obscures the larger particles on the membrane making contamination evaluation impossible. Typical Dynamic (Operating) Clearances 10 *Data from STLE Handbook on Lubrication & Tribology (1994) “No system has ever failed from being too clean” To determine the recommended cleanliness level for a component use the 'Fluid Cleanliness Level Worksheet' on page 27. Component Details Clearances Servo 1 - 4 µm Valves Proportional 1 - 6 µm Directional 2 - 8 µm Variable Volume Piston Pumps Piston to Bore 5 - 40 µm Valve Plate to Cyl 0.5 - 5 µm Vane Pumps Tip to Case 0.5 - 1 µm Sides to Case 5 - 13 µm Gear Pumps Tooth Tip to Case 0.5 - 5 µm Tooth to Side Plate 0.5 - 5 µm Ball Bearings Film Thickness 0.1 - 0.7 µm Roller Bearings Film Thickness 0.4 - 1 µm Journal Bearings Film Thickness 0.5 - 125 µm Seals Seal and Shaft 0.05 - 0.5 µm Gears Mating Faces 0.1 - 1 µm Water Contamination in Oil 11 Water contamination in oil systems causes: • Oil breakdown, such as additive precipitation and oil oxidation • Reduced lubricating film thickness • Accelerated metal surface fatigue • Corrosion Sources of water contamination: • Heat exchanger leaks • Seal leaks • Condensation of humid air • Inadequate reservoir covers • Temperature reduction causes dissolved water to turn into free water W at er C o nc en tr at io n (P P M ) Oil Temperature (°C) 25 50 75 50 100 150 100 0 0 Oil Temperature (°F) 77 122 1670 Free Water Dissolved Water Ref: EPRI CS-4555 Turbine oil To minimise the harmful effects of free water, water concentration in oil should be kept as far below the oil saturation point as possible. 10,000 PPM 1% 1,000 PPM 0.1% 100 PPM 0.01% Operating Principle of Pall Fluid Conditioning Purifiers 12 Pall Fluid Conditioning Purifiers remove 100% of free water and entrained gases, and up to 90% of dissolved water and gases Typical Applications • Hydraulic oils • Lubrication oils • Dielectric fluids • Phosphate-esters • Quenching fluids Inlet contaminated fluid Outlet dry fluid Outlet exhaust air Vacuum: Expansion of air causes the Relative Humidity to decrease Inlet ambient air Principle: Mass transfer by evaporation under vacuum Free Water Dissolved Water Very thin film of oil Dry air Pvacuum -0.7 bar Pall HNP006 Oil Purifier Water Content Analysis Methods 13 Method Units Benefits Limitations Crackle Test None Quick indicator of Does not permit presence of free detection below water saturation Chemical Percentage or PPM A simple Not very accurate (Calcium hydride) measurement of on disolved water water content Distillation Percentage Relatively unaffected Limited accuracy by oil additives on dry oils FTIR Percentage or PPM Quick and Accuracy does not inexpensive permit detection below 0.1% or 1,000 PPM Karl Fischer Percentage or PPM Accurate at Not suitable for high detecting low levels of water. levels of water Can be affected (10 - 1,000 PPM) by additives Capacitive Sensors Percentage of Very accurate at Cannot measure (Water Sensors) saturation or PPM detecting dissolved water levels above water, 0 - 100% of saturation (100%) saturation. WS04 Portable Water Sensor WS08 In-line Water Sensor Monitoring and Measurement 14 Obtaining accurate and reliable fluid cleanliness data quickly in order to detect abnormal contamination is a key factor in ensuring the efficiency of industrial processes and reducing downtime. Reliable Monitoring Solutions... ............................................. ...Whatever the Conditions...Whatever the Fluid PCM400W Portable Cleanliness Monitor Provides an assessment of system fluid cleanliness • Proven multiple mesh blockage technology. • Results not affected by water or air contamination. • Designed for use with dark or cloudy fluids. • ISO 4406, NAS 1638 or SAE AS4059 data output. PFC400W Portable Particle Counter Measures the size and quantity of particles in industrial system fluids • Proven laser light blockage technology. • Measures the size and quantity of particles in industrial fluids. • ISO 4406, NAS 1638 or SAE AS4059 data output. Pall Water Sensor The next generation of in-line monitors for water contamination in system fluids • Measures dissolved water content as % of saturation(%sat) or PPM. • Portable and in-line models. PCM400W PFC400W WS08 WS04 Extraction Component Cleanliness Measurement 15 Component Cleanliness Cabinets facilitate the accurate, reliable and repeatable determination of component cleanliness. Extraction AnalysisAnalysis Process OptimizationProcess Optimization The Pall PCC 500 series cabinets combined extraction and analysis using filter blockage measurement techniques which are not affected by the presence of water or air in fluids. Blank Component Contamination • Developing optimization • Developing and validation of cleanliness standard • Cleaner fluids • Laboratory services Component Contamination Microscopic Analysis PCC041 All stainless steel cabinets feature: • Controlled extraction environment • Automated cleaning to ‘blank’ values • Pressurised solvent dispensing and recycling circuits. • Meet ISO 18413, ISO 16232 and VDA 19 procedures. PCC030 PCC500 Fluid Sampling Procedure 16 Method 1 Small ball valve with PTFE or similar seats, or a test point 1. Operate the system for at least 30 minutes prior to taking sample in order to distribute the particulate evenly. 2. Open the sampling valve and flush at least 1 litre of fluid through the valve. Do not close the valve after flushing. 3. When opening the sample bottle, be extremely careful not to contaminate it. 4. Half fill the bottle with system fluid, use this to rinse the inner surfaces and then discard. 5. Repeat step 4 a second time without closing the valve. 6. Collect sufficient fluid to fill 3/4 of bottle (to allow contents to be redistributed). 7. Cap the sample immediately and then close the sample valve. Caution: Do not touch the valve while taking the sample. 8. Label the sample bottle with system details and enclose in a suitable container for transport. Method 2 Valve of unknown contamination shedding capabilities 1. Operate the system for at least 30 minutes prior to taking sample in order to distribute particulate evenly. 2. Open the sampling valve and flush at least 3 to 4 Litres of fluid through the valve. (This is best accomplished by connecting the outlet of the valve back to the reservoir by using flexible tubing). Do not close the valve. 3. Having flushed the valve, remove the flexible tubing from the valve with the valve still open and fluid flowing. Remove the cap of the sample bottle and collect sample according to instructions 4 to 6 of Method 1. 4. Cap the sample immediately and then close the sample valve. Caution: Do not touch the valve while taking the sample. 5. Label the sample bottle with system details and enclose in a suitable container for transport. Introduction There are 4 methods for taking fluid samples. Method 1 is the best choice followed by Method 2. Method 3 should only be used if there is no opportunity to take a line sample, and Method 4 should only be used if all others are impracticable. DO NOT obtain a sample from a reservoir drain valve. Always take the sample under the cleanest possible conditions, and use pre-cleaned sample bottles. If there are no line mounted samplers, fit a Pall sampling device to the Pall filter. Fluid Sampling Procedure (continued) 17 Method 3 Sampling from Reservoirs and Bulk Containers Applicable only if Methods 1 and 2 cannot be used 1. Operate the system for at least 30 minutes prior to taking sample in order to distribute the particles evenly. 2. Clean the area of entry to the reservoir where sample will be obtained. 3. Flush the hose of the vacuum sampling device with filtered (0.8 µm) solvent to remove contamination that may be present. 4. Attach a suitable sample bottle to the sampling device, carefully insert the hose into the reservoir so that it is mid-way into the fluid. Take care not to scrape the hose against the sides of the tank or baffles within the tank as contamination may be sucked into the hose. 5. Pull the plunger on the body of the sampling device to produce vacuum and half fill the bottle. 6. Unscrew bottle slightly to release vacuum, allowing hose to drain. 7. Flush the bottle by repeating steps 4 to 6 two or three times. 8. Collect sufficient fluid to 3/4 fill the sample bottle, release the vacuum and unscrew the sample bottle. Immediately recap and label the sample bottle. Method 4 Bottle Dipping Least preferred method 1. Operate the system for at least 30 minutes prior to taking sample in order to distribute particulate evenly. 2. Clean the area of entry to the reservoir where sample will be obtained. 3. Ensure the outside of the bottle is clean by flushing with filtered solvent. 4. Remove cap from the sample bottle. Carefully fill the sample bottle by dipping it into the reservoir and then discard the fluid after rinsing the inside of the sample bottle. 5. Repeat step 4. Carefully fill the sample bottle, cap immediately and wipe the outside. 6. Secure any openings in the reservoir. Note: Incorrect sampling procedures will adversely effect the cleanliness level in the sample bottle. It is impossible to make a sample cleaner than the actual system but very easy to make it dirtier. Filter location 18 Flushing Filter • To remove particles that have been built-in to the system during assembly or maintenance before start-up. • To remove large particles that will cause catastrophic failures. • To extend 'in-service' filter element life. Pressure Line • To stop pump wear debris from travelling through the system. • To catch debris from a catastrophic pump failure and prevent secondary system damage. • To act as a Last Chance Filter (LCF) and protect components directly downstream of it. Return Line • To capture debris from component wear or ingression travelling to the reservoir. • To promote general system cleanliness. Air breather • To prevent ingression of airborne particulate contamination. • To extend filter element service life. • To maintain system cleanliness. Kidney loop/off-line • To control system cleanliness when pressure line flow diminishes (i.e. compensating pumps). • For systems where pressure or return filtration is impractical. • As a supplement to in-line filters to provide improved cleanliness control and filter service life in high dirt ingression systems. Additional filters should be placed ahead of critical or sensitive components • To protect against catastrophic machine failure (often non-bypass filters are used). • To reduce wear • To stabilize valve operation (prevents stiction). Return line filter Pressure line filter Kidney loop/off-line filterOil transfer filter cart Air breather Fluid Conditioning Purifier 20 Bulk Fluid Storage Minimised Waste Disposal Press Parts Washing Test Facility U N D E R S TA N D I N G T O TA L F L U I D M O V E M E N T Supply Machining Centres Injection Moulding Coolant Wash fluid PPaallll CCoonnddiittiioonn MMoonniittoorriinngg eeqquuiippmmeenntt The Pall concept of Total Cleanliness Management in practice