performance and reliability of machines – My Assignment Tutor

Department ofEngineering andMathematicsAssignmentSpecification27/09/21 Session: 2021-22Module learning outcomes to be assessed: Analyse the performance and reliability of machines. Design systems for maintenance, reliability and good performance. Propose and justify measurement and monitoring systems for plant. Predict the behaviour of mechanical engineering systems. Criticise the design and implementation of machine systems from costand efficiency standpoints.References/recommended reading:See Blackboard site – Support Resources for information and Reading ListsPlease ensure that all sources of information used are referenced. For guidancesee assessments are subject to SHU’s collusion and plaigiarism regulations.Please refer to: Module: 55-701475 Equipment Engineering and DesignModule Leader: David TipperAssignment number/title: Task 1Academic contact for guidance: D. Tipper , S. O’GradyMaximum word count : 2500 Words Maximum equally split between problems A and B.Percentage contribution to overall module mark: 50%Deadline for submission: 11/11/2020Method and Location for Submission: Blackboard SubmissionDeadline for return of feedback: 02/12/2020 Task 1 – (A) Factory Maintenance Problem (D. Tipper)Problem backgroundPart of a factory that manufactures extruded building products is shown in Fig. 2. Dust that isprocessed in another factory is loaded by a wheeled shovel into a hopper and is raised via aninclined conveyor and bucket elevator to the top of the system. The dust is then distributed tostorage hoppers by a large scraper chain conveyor.Each hopper is equipped with an extract conveyor which loads dust onto a collection conveyorand then onto the machine feed conveyor.The machine hopper acts as a surge hopper, allowing an even and controllable feed of dust tobe added to the mixer of the main extrusion machine.Much ancillary equipment has been excluded for clarity.Fig. 1The large making machine (Fig. 1) consists of a single shaft mixer where water and dust arecombined and then fed through a de-airing chamber into the extruder. None of the forming orhandling equipment is shown.Product from the extrusion machine is loaded onto refractory lined bogies and processedthrough a dryer and kiln, which is a continuous process. If the firing process is slowed orstopped, large scrap rates and a kiln fall could follow.The main extrusion process has to run 16 hours per day but this can fluctuate with demand.Because this is only part of a larger factory, if staff are not working on this system, they areemployed elsewhere.Two fitters and an electrician are always on duty within the factory as a whole.The TaskThe immediate task is to suggest a maintenance strategy for the equipment. The strategyshould contribute to a factory wide Reliability Centred Maintenance strategy. This includesmobile and electrical equipment. Full explanations must be given and related to thisequipment.Please note any suitable condition monitoring techniques that may be appropriate, which piecesof equipment they relate to and why.FMEA would not be appropriate as it is not expected that students have a full understanding ofthe equipment. Suggest and justify any modifications which would increase reliability of theplant. This may include changes to layout or maintenance policies.It is essential that any answers are very specific to this problem. Descriptions ofgeneral / generic design issues, management techniques etc. are not acceptable andwill lose marks; all discussions must be related to the problem and describe how theproposed changes would improve the current solution.Fig. 2 Plant nameDescriptionFunctionComplexityMaintenancedifficultyLarge wheeledloadingshovel.Bucket loader.Loads processeddust into thesystem.HighVery easyInclineconveyor.Belt conveyor withtroughing idlers. Driven byshaft mounted gearbox.Raises dust frombelow ground tohopper.LowVery easyBucketelevator.Rotating belt with pressedsteel buckets. Driven byshaft mounted gearbox.Raises dust to topof hoppers.LowReasonableScraper chainconveyor.300mm centre roller chainconveyor with scrapersattached to chain by Kbrackets. Driven by largeworm and wheel gearbox,direct coupled.Drags dust to eachhopper. Gate valvescan isolate hopperfrom scraper chain.Low tomediumDifficult on topof hoppers.Pooraccessibility tolarge drive.Dust hoppers.Hopper.Stores dust (100t ineach). Onlyrequires cleaninginternally.Very lowN/AExtractconveyor.Belt conveyor withtroughing idlers. Driven byshaft mounted gearbox.Removes dust fromhopper.LowEasyCollectionconveyor andmachine feedconveyor.Belt conveyor withtroughing idlers. Driven byshaft mounted gearbox.LowEasyMachine feedhopper andconveyor.Hopper. Reduces surgesgiving feed to the machine(1t capacity)Has simple extractconveyor to feedmixer.LowVery easyMakingmachinemixer.Single shaft mixer withhigh chrome steel blades.Mixes dust, waterand lime.Very highVery difficultMakingmachineextruder.High chrome steel wormsand liners.Extrudes product.Very highExtremelydifficult Table 1: Illustration of likely reliability and accessibilityCheck List This is a report, so only a short introduction is required. Do not restate the problem. Do not pad your report out with words that do notanswer the specific requirements of the case study. Word count must be shown on the cover sheet and is absolute. Do not explain what PM, CBM and breakdown maintenance is. It will be assumedthat they are terms known to all readers of the report. Do not describe specific maintenance tasks, although appropriate CM taskswould be appropriate. Remember this is about strategy. Do not attempt to do a Failure Mode Analysis; you do not have sufficientinformation. Do not try to add costs and hourly rates as you do not havesufficient information. The term management in this context relates to RMC. (Process management,spares inventory, information, some redesign at a system level etc.). Please use maintenance books, not web sources, on conveyor maintenance. Thisis about maintenance strategy, the mix of different maintenance types and thejustification. Work without discussion/justification is not acceptable. Please check your work, unintelligible grammar and English will not be accepted.Task 1 (B) – Hydraulic Industrial Case Study (S. O’Grady)Background (Refer to figure 3)You are the factory engineer working in a highly automated modern earthmovingequipment factory that has been in operation for some years. You are in charge of theequipment described below. The circuit shows a hydraulic system. The hydrauliccylinder (item 2) is one of several fully automatic clamping stations that hold largepieces of steel together while they are welded together.The cylinder operates and holds a nominal pressure of 175 bar for approximately 15minutes, then is off for approximately 2 minutes while the welded component isremoved and recharged with unwelded components. The relief valve (item 7) is set to200 bar. Materials for the production process are rigorously checked and are veryconsistent.When pressure is required for the welding process, the Programmable Logic controller(PLC) energises the 2 position, 2 port spring return solenoid valve (item 6).When the correct clamping pressure has been achieved, the pressure switch detectssystem pressure as being correct and the resulting signal is used by the PLC to signalvalve 6 via its solenoid to unload the pump. An accumulator is fitted to accommodateany equipment internal leakage.During the welding process; if the pressure switch (item 1) sees a drop in pressurebelow the pressure switch differential setting; valve 6 is re–energised, until correctclamping pressure is regained.The machine is capable of operating continuously as production requirements demand.The Hydraulic power-pack is outside the main machine guard and can be adjusted andvisually inspected safely while the machine operates (and is away from the weldingprocess). In general the plant is so well automated, personnel may manage a numberof different machines at any time.BS 2917-1:1993 ISO 1219-1 should prove useful.Remember circuits are always drawn in an ‘at rest position’.Figure 3A fixed speed AC motor is used to power the system. ItemDescription11Strainer (In tank Suction)10Fixed displacement gear pump approx. 5 l/ min capable of achieving210 bar9Fixed speed Motor (AC)8Pressure filter with bypass (opens at 2bar)72 stage Pressure Relief Valve cracks at 200 bar62 Position Directional Control valve5Non Return Valve4Accumulator: Nitrogen filled bag type33 Position Directional Control Valve2Hydraulic Cylinder1Pressure switch activated 175 bar, differential 5 bar Figure 3. LegendThe problemWhen you arrive in the morning the oil reservoir is so hot you cannot hold yourhand on it. This is not the normal state; the tank is usually at ambienttemperature.The oil level is correct and the regular oil sample checks show there to be noissue with contamination.The system seems to be losing its capability to operate correctly.What are the possible causes of the problem? These must be precisely defined.Suggest any improvements to the circuit that might protect against thisoccurrence in the future. You are not expected to suggest major hydraulicchanges as the circuit is a standard unloading circuit that works well and hasworked well for many years.Full explanations are required as to how you arrive at your conclusion, with anytheory being applied to the problem at hand. You must tell me how theissues/faults you identify have resulted in the symptoms being experienced.Please be brief, succinct and to the point. I see this as a technical report.Use your experiences gained from the seminars as well as reading on the subjectto inform your answer.All theory and discussions must be directed and related to this problem. Lists ofgeneral/generic ideas, issues, theories etc. are not acceptable and will losemarks; all discussions must be related to the problem at hand.You must use the correct terminology, such as relieving, unloading etc. and whenreferring to equipment in the case study, ensure the correct names andidentification numbers are always used.Do not re-state the problem in your answer.I think this hydraulic section of the case study can easily be completed inapproximately 1000 words – there is a maximum word count of 1200 words.There is no minimum word count, nut you will be heavily penalised if you do notconvey the information required to answer the problem.Report requirementsReports must be handed as electronic versions on Blackboard. Any work inexcess of word count will not be marked.Please check your work; unintelligible grammar and English will will be heavilypenalised.Please name your report with your last name and then your first name. No otherinformation to be added, i.e. Bloggs Joe.This is to be your work and your work only. Please reference work by othersfully and be aware we also check for collusion.These requirements are to help you develop a professional report writing style.Your report is to conform to the following: The report has to be a single document and in MS Word format. Images to be readable without having to rotate the document. Images should be cropped and arranged to give the clearest view of yourwork. Word limits must be observed. 12 pt Ariel font, 2.0 pt line spacing. Pages to be numbered. All figures/drawings/photos to be numbered and titled. Work of others (pictures, diagrams etc.) to be referenced.


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