Tuesday, June 4, 2019

Design of Condition Monitoring (CM) system of a Case Study

Design of teach monitor (CM) system of a Case StudyTerm / AbbreviationDefinitionCBWContinuous Batch automatic washerCMCondition Monitoring blastDeutsches Institut fur Normung (German Institute for Standardization)FFTFast Fourier TransformFTIRFourier Transform Infrargond SpectroscopyIRInfra-RedOEMOriginal Equipment ManufacturerP-F potential drop to Functional FailurePMPreventive careSGSSpring Grove ServicesTANTotal Acid biteTBNTotal Base NumberTWFTime Wave FormWDAWear Debris digestSpring Grove Services has firm to embark on a Condition Monitoring approach for the alimony of its or so wax of life equipment.Criticality was established by carrying out a study on the main Utilities and deal systems/machinery.This report includes info and movies from a Thermography study, carried out at SGS, as this typeface of CM has already commenced. The findings identified in this exercise make up highlighted potential ushers of failure in the Novopac shrink-wrap lines.Lubrication and p alpitation Analysis studies take away yet to commence so lead be considered from a look-ahead perspective. The areas of focus present are the 18 decimal point CBW and the Kaeser air compressor respectively. in that respect will be predictions and estimates made on manageable findings and need follow-up actions.The report undertaken here confirms to the author the necessity of introducing CM for equipment that is central to the successful raceway of the SGS plant in Cork.Spring Grove Services is one of Irelands leading laundry rental service providers. SGS has four major processing sites in Ireland.The disdain model functions by supplying linen paper to customers on a rental basis. This is then collected later on use and cleaned before re-supply. Clients are supplied from a kitty-cat stock i.e. linen is non specific to any one client.The plant in Cork, which is featured in our case study, processes on average 330,000kgs of linen per calendar week which equates to approxi mately 660,000 individual pieces. Run hours are 85 per week. Its customers include Irelands biggest hotels and hospitals.There is a real time aspect to this industry in the sense that linen processed today may well be used in a hotel or hospital tonight. This same linen will probably have only arrived in the laundry this morning in a soiled state.Lengthy batch release times due to quality inspections do not feature as they would in the pharmaceutical and healthcare products industries. This does not mean that there are poor quality standards, it just means that there is a minimum of time to ascertain them.This super-lean model requires maximum availability of plant equipment so effective maintenance is parnitty-gritty. The operate context is also a cistron in the maintenance strategy equipment with many moving parts operating in a hot, humid and/or dusty environment.Preventive and Corrective Maintenance has historically been accepted practice with SGS but Condition Monitoring is c oming more to the forefront for the most critical equipment.SGS is part of the European wide Berendsen group.The for the first time step in the Condition Monitoring journey was to identify the most critical equipment. This would naturally become the focus of CM.Appendices A and B illustrate how Utilities and Process systems interact at SGS.Appendix C explains in detail, utilise a Criticality make headway Scheme (Wheelhouse, 2014), how the results in show 1 were attained.Figure 1 SGS Criticality CurveFigure 1 expressive styles criticality for the various Utilities and Process systems/equipment in Spring Grove Services.From Figure 1, we can deduce that the most critical assets are the CBWs, the Plastic Wrappers and the air Compressor. On further analysing the failure modes associated with this equipment, we can decide on where the exact focus of CM will be18 Stage CBW This machine is the work horse of the Wash House as it alone processes 50% of the linen. Its most critical piece of equipment is the drive beat back/ gear case assembly. We will apply Lubrication Analysis to the gearbox.Plastic Wrappers These pieces of equipment form the final stage of the laundering process. Failure here creates a severe bottleneck. We will apply Thermographic Analysis to the electrical control panels.Air Compressor If the compressor stops, production stops as there is no redundancy available. We will apply Vibration Analysis to the bearings as they are overdue replacement according to Original Equipment Manufacturer specification.3.1 Equipment DescriptionFigure 2 Lenze GST Geared beat back (Source Geared Motor Spares)Figure 2 shows the type of geared motor used to drive the 18 Stage CBW (Geared Motor Spares).Lenze GST Helical Gearbox actor 18.5kWSpeed 331rpmTorque 518NmRatio 4.4571 result Code GST09-2MVBR180C12Oil manufacture/type Shell Omala S4 GX 320Quantity of oil 4.8 litres3.2 exam OverviewThe main purpose of carrying out lubrication analysis on this gearbox is to fi nd out its health. The health of the lubricating oil itself is of secondary importance to SGS as it is a relatively inexpensive and easy task to replace. Because of these considerations our findings on Wear Debris Analysis (particle count) and suffice Analysis will be used to make an boilersuit estimation of system health.Where possible analysis performed through In-line or On-line methods is often preferable. only in this instance, neither of these options is possible so Off-line sampling will have to suffice.Off-line analysis does stock-still provide increased scope for evaluating a greater variety of debris (Pruftechnik, 2002).Figure 3 GST gearbox lubrication service points (Source Geared Motor Spares) Figure 3 illustrates the various lubrication service points on a Lenze GST type gearbox (Geared Motor Spares).To take an oil have, we will employ the side by side(p) procedureEnsure that the gearbox/oil is at normal operating temperature.It is not safe to take a sample while t he gearbox is in operation due to the proximity of hazardous moving parts. We will thereof instead stop the machine and take a sample as soon as the drive motor is safely isolated.100ml will be extracted using a vampire Pump and entering the gearbox through the Breathing/oil filler plug as displayed in Figure 3.This method of lineage is known as the Drop Tube Sampling Method.Figure 4 Drop Tube Sampling Method (Source Zidoune)Figure 4 shows a Vampire Pump extracting oil using the Drop Tube Sampling Method (Zidoune).Precautions when samplingRecord time, date and operating conditions.Oil must be at operating temperature.Ensure clean bottles and new tubing are used.Take oil from middle of gearbox i.e. not overly close to the bottom. A roiling zone is best.Samples should be sent for laboratory testing without delay.Poor sampling = poor results = poor decisions (Zidoune, 2013).3.3 Test FindingsVisual InspectionThis can be performed by onsite staff prior to laboratory analysis and obse rvations will be aimed at the followingFoaming an indication of contamination, passage through restricted openings or extravagant churning.Emulsion water has entered the gearbox.Darkening oxidation has occurred or oil has been exposed to excessive heat.Laboratory AnalysisOn receiving laboratory results, we will consider the following factors in estimating the health of the gearboxFTIR This provides information about oil chemistry and particulates. It can also determine if there has been a decrease in loveable content much(prenominal) as corrosion inhibitors.Viscosity This can tell us much about the lubricants condition. It can also give us an sixth sense into system health when considered alongside factors such as detergency and dilution.Metal Concentration This is a key health indicator. The presence of certain metals can point towards the defect location e.g. Lead and Tin detected in large amounts indicates wear of a white metal bearing.TAN/TBN Acid number determines am ount of oxidation present in the oil. Base number is an indication of the capacity to neutralise acids.Fault Level SettingsGearbox or oil manufacturers should be consulted, however setting useful alarm limits can be subjective as there are many variables in the operating context that it is not possible to account for in their specifications.Alarm limits are best set by initially estimating, based on specifications, and then gathering data over a period of time to tune the initial estimates. This will help reduce both false triggers and potential failures.As there are three CBWs in the wash house with identical drive systems, there is a likelihood that a gearbox will be fully overhauled in the not too distant future. We could use this opportunity to get data from perfectly healthy system i.e. a reconditioned gearbox with new oil.ISO CodingSample Standard Cleanliness sharpen for an Industrial Gearbox ISO 17/15/12 (Angeles, 2003)Table 2Table 2 contains hypotethical data that we would expect to see in an oil sample taken from a healty gearbox. Using ISO 4406 methods with this data would give us a code of 17/15/12.3.4 ConclusionTrendingIt is imperative that a trend is demonstrable from the successive analysis exercises. This will result in a graph curve which displays system health and allow for a timely maintenance hindrance when required.Recommended sampling oftennessCare must be taken here as 100ml test amounts will render the gearbox empty of oil after 48 samples.Topping up the gearbox after each sample is not recommended as introducing new oil dilutes the existing content and thus distorts WDA data. flow rate oil replacement interval is every 4 years.Initial sampling frequency will be every 6 months with the gearbox oil train topped up every 12 months.Quick winsSpurlock (n.d.) states that one of the most common points of ingress for contamination in a gearbox is the OEM breather. It is recommended that an aftermarket breather be used instead.4.1 Equipment DescriptionFigure 5 Novopac ANL 090 Wrapper (Source Bidspotter)Figure 6 Novopac BM2009 Heat shrinking Oven (Source Bidspotter)Figures 5 and 6 show examples of the Novopac Wrapper and Heat Shrinking Oven used in SGS (Bidspotter).Novopac ANL 090 Wrapper and BM2009 Heat Shrinking Oven (both function as a combined unit).Power 41kW.Output per min. 8/16 packs.4.2 Testing OverviewIt was decided that SGS would purchase a thermographic camera and have one of the maintenance technicians trained in its operation.The supervisor consulted with the technician immediately after the study was completed and again when the full report was completed.4.3 Test FindingsThere were two areas that were cause for concern the three phase power supply connecter and the DIN rail mounted contactors. leash Phase Power Supply ConnectionFigure 7 IR imageFigure 8 Standard imageTable 3Figures 7 and 8 show both an IR and a standard image of the three phase connection block. Table 3 lists the data recorded by the ca mera in this instance.Action taken The hot spot found in Figure 7 was found to be a give up connection on the DIN rail connection block. Tightening the same connector resolved the issue.DIN Rail Mounted ContactorsFigure 9 IR imageFigure 10 Standard imageTable 4Figures 9 and 10 show both an IR and a standard image of the DIN rail mounted contactors. Table 4 lists the data recorded by the camera in this instance.Action taken Figure 9 indicates that there is a temperature build up between the contactors. On consulting previous reports, it was found that the temperature readings were similar during the last thermographic study. At this point the contactors were actually located closer together. A pass was made at that time to space out the contactors to allow for extra cooling. However this has made no difference but since there has not been deadening in the state of the contactors, SGS has decided not to take any further action at present.4.4 ConclusionThe overall conclusion is that , beyond the tightening of the loose connection, there is no serious action required regarding repairs.However SGS has realised that there are shortcomings in the testing procedures which are mainly down to the technician not being trained to the proper standard. Listed below are the observations and recommendations relating to this viewpointThe approach being applied is a Qualitative one which is sufficient for identifying the presence of a fault. It is also effective as a comparative technique.A Qualitative approach measures the Blackbody Apparent Temperature. Neither reflected/ transfer radiation nor emissivity has been accounted for.To get a original temperature reading, a Quantitative approach would be required. This will not only identify the presence of a fault but also its severity.Reflected/transmitted radiation is accounted for by entering the ambient temperature in the IR Camera. This can be done using pre-measured or estimated values. A correct entry here would provide the Blackbody temperature.Emissivity can be accounted for by entering a pre-measured or library values. A correct entry here, combined with accounting for the reflected/transmitted radiation, would provide the actual temperature.5.1 Equipment DescriptionFigure 11 Kaeser CS76 (Source Synairgies)Figure 11 shows the type of Kaeser air compressor used in SGS (Synairgies).Kaeser CS76.Type Rotary screw wet.Power 45kW.Motor speed 3000rpm.Mains frequency 50Hz.Pressure 7.5bar.Year of manufacture 2004.Total running hours 53563.On-load running hours 42789.Recommended frequency for bearings replacement 35000 hours this activity has yet to be completed.5.2 Testing OverviewThe most likely cause of a screw compressor to fail is its bearings (KCF Technologies, n.d.).Accelerometer LocationsFor our Kaeser machine, we will apply shaking observe at the radial bearing positions of both the motor and compressor.This area will get a particular focus because OEM specifications suggest the bearings shou ld have already been replaced. SGS is hoping that vibration analysis will give a true indicator of bearing condition and thus inform of the optimum time for bearing change-out.Figure 12 Sensor locations (Source KCF Technologies)Figure 12 shows typical raise positions, in yellow, for sensors to measure vibration at motor and compressor radial bearings (KCF Technologies).Mounting techniqueAccelerometers will be stud mounted to help ensure the most accurate readings.Accelerometer selection and equipment set-upFrequencies associated with bearings usually occur in the 1 to 5 kHz range.For this application an accelerometer with 25 kHz natural frequency is required.Sampling frequency (fs) = 2.56 x 5000 = 12800 Hz.For Fast Fourier Transform Spectrum Analysis, to achieve a frequency resolution of less than 1Hzdf = fs/N 1N is the number of data points.N = 214 = 16,384fs/N = 0.78125Crest Factor or Kurtosis on Time Wave Form Acceleration signal can be employed to assist with diagnosis.Veloci ty and Acceleration will be the main focus for FFT.5.3 Test FindingsTWF and FFTFor fault diagnosis, we will refer to TWF and FFT graphs.Figure 13 TWF and FFT (Source Sinha)Figure 13 displays vibration acceleration measurement for a ball bearing in the initial fault stage (Sinha).Vibration Alarm and Fault level examplesTable 5 (Source Zargar)Table 5 lists vibration limits for a similar size and specification to the Kaeser CS76 (Zargar).5.4 ConclusionA successful vibration monitoring program can be most difficult to attain for screw compressors. This is because of the high frequencies associated with the bearings, gearbox, male and female rotors. The associated noise pollution of the compressor can cause additional monitoring problems (Zargar, 2013).For the Kaeser compressor, there is a risk that bearing wear is present because of the hours run by the machine. However we cannot draw a firm conclusion on this until we develop a trend based on several sets of analysis data.The ultimate goal is to capture the point at which the bearings begin to deteriorate and from there successfully monitor the P-F interval. This will enable a well-judged maintenance intervention.CM want to have If sufficient finance was available, a great option would be to invest in an Online monitoring system and have data fed back to a central PC. The software package could then issue periodic reports as well as alarm condition notifications.It is clear, I believe, from this report that embarking on a Conditioning Monitoring political platform would bring great benefit to SGS.As well as the immediate gains to be made on the above equipment, the following should also result as pleasant side effectsAn awareness will have developed among the key stakeholders of the advantages of CM over other types of maintenance.Technical staff will have an opportunity to upskill in either carrying out CM activities such as the Thermography study or be involved in interpreting results from Lubrication and Vibr ation analysis.There will be a willingness to roll out CM to other pieces of equipment. Thermography is an obvious contender as the equipment is already purchased.Downtime in the Wash House should be reduced as potential failures in the 18 Stage CBW drive gearbox will be identified before descending into functional failures. Again, as soon as this benefit is realised, this approach should carry crossways to other equipment.The criticality study which underpins the CM strategy will help focus technical resources on the most important equipment to the business.The expected success of the programme in the Cork plant should result in adoption of CM across the other sites in Ireland as there has always been close cooperation in terms of maintenance practices and parts sourcing.There will be an opportunity for the maintenance department to come to the forefront of the company when reporting the expected unafraid news stories to emerge from adopting this new maintenance approach.Continuo us improvement will organically develop from CM and bring kudos to the maintenance team.The general non-contact disposition of CM will enhance safe working practices.The non-intrusive nature of CM will result in less equipment stoppages and reduced maintenance induced failures.The maintenance team will be encouraged to work more closely with equipment and components suppliers. This will help better inform future selection of machinery.It should be the starting time of a new maintenance culture across the organisation.Angeles, R. (2003). Tables on Oil Analysis. Online. easy from http//www.rsareliability.com/Oil%20Analysis%20Tables.pdf Accessed 12 November 2016.Bidspotter (n.d.). Impianti Novo Pac heat shrink-wrap tunnel.Online. Available from https//www.bidspotter.co.uk/en-gb/auction-catalogues/es-group/catalogue-id-ed10487/lot-85e81420-d4ca-4279-8ccd-a64400d6ecc2 Accessed 08 November 2016.Geared Motor Spares (n.d.). Lenze GST Geared Motors.Online. Available from http//www.gearedmo torspares-lenzegst.co.uk/lenze-gst-gearbox-products/lenze-185kw/lenze-185kw-277rpm/lenze-gst-geared-motor-185kw-277rpm-619nm-c-16/ Accessed 08 November 2016.Geared Motor Spares (n.d.). L-force Geared Motors.Online. Available from http//www.gearedmotorspares-lenzegst.co.uk/media/1001/gst-gfl-gks-gkl-gkr-gss-operating-instructions.pdf Accessed 11 November 2016.KCF Technologies (n.d.). Vibration Monitoring of Compressors. Online. Available from https//kcftech.com/smartdiagnostics/resources/application%20briefs/Application%20White%20Paper%20Compressors%20web.pdf Accessed 16 November 2016.Pruftechnik (2002). An Engineers Guide to bang Alignment, Vibration Analysis, Dynamic Balancing Wear Debris Analysis. Online. Available from http//www.pruftechnik.com/fileadmin/pt/Downloads/Brochures-Flyers_SPECIAL/Engineers_Guide_ALI_CM/EngineersGuide2012.pdf Accessed 13 November 2016.Sinha, J. (2016). PG Course in Reliability Engineering and Asset steering, Unit M04Condition Monitoring. School of M echanical Aerospace and Civil Engineering. University of Manchester.Spurlock, M. (n.d.). Reducing Gearbox Oil Contamination Levels. Online. Available from http//www.machinerylubrication.com/Read/28393/gearbox-oil-contamination Accessed 11 November 2016.Synairgies (n.d.).Synairgies Compresseurs Doccasion.Online. Available from http//www.synairgies.com/pl/Air/Spr%C4%99%C5%BCarki-%C5%9Brubowe-smarowane/Kaeser/Kaeser-CS-CSD-CSDX/Kaeser-CS76-45kW-Ref12115.htmlAccessed 08 November 2016.Zargar, O. A. (2013). Hydraulic upset in Oil Injected Twin Rotary Screw Compressor Vibration Analysis. Online. Available from http//waset.org/publications/9997612/hydraulic-unbalance-in-oil-injected-twin-rotary-screw-compressor-vibration-analysis-a-case-history-related-to-iran-oil-industries-Accessed 17 November 2016.Zidoune, M. (2013). Lubricants Handling and Analysis. Online. Available from http//www.slideshare.net/marcpalud/tribologik-lubricant-handling-and-analysis-presentation Accessed 11 November 20 16.Wheelhouse, P. (2014). Exercise 3_5 Criticality, Unit M01 Asset Management Maintenance Strategy. School of Mechanical Aerospace and Civil Engineering. University of Manchester.8.1 Appendix AFigure 14 SGS Utilities SystemsFigure 14 shows the systems which form Utilities at SGS.8.2 Appendix BFigure 15 SGS Process System/EquipmentFigure 15 shows a high level view of process systems and equipment at SGS.8.3 Appendix CCriticality Scoring Scheme(Wheelhouse, 2014)The plant has decided on a criticality scoring scheme which consists of four different factors which will be multiplied together to give an overall score for equipment criticality. These factors are Redundancy, Failure Likelihood, Failure Duration Financial Impact. A scoring scheme has been devised for each factor as followsRedundancy = Number of units required / Number of units availableLikelihoodKeywordEvents per YearScoreNever00Very unlikely Unlikely 0.2 0.6 2Probable 1.0 1.5 3Almost certain 24DurationKeywordScoreHours1D ays2Weeks3Months4Financial ImpactKeywordScore jam cost only1Additional cost penalty2Potential loss of sales3Immediate loss of sales4Table 6 lists equipment criticalities as calculated at SGS.ReferencesAngeles, R. (2003). Tables on Oil Analysis. Online. Available from http//www.rsareliability.com/Oil%20Analysis%20Tables.pdf Accessed 12 November 2016.British Standards Institution (1999). BS ISO44061999. Hydraulic fluid power Fluids Method for coding the level of contamination by solid particles. create under the authority of the Standards Committee.Felten, D. (2003). Understanding Bearing Vibration Frequencies. Online. Available from http//electromotores.com/PDF/InfoT%C3%A9cnica/EASA/Understanding%20Bearing%20Vibration%20Frequencies.pdf Accessed 16 November 2016.Geared Motor Spares (n.d.). L-force Geared Motors.Online. Available from http//www.gearedmotorspares-lenzegst.co

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