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8 Advanced Diploma of Mechanical Engineering Technology7 Advanced Diploma of Mechanical Engineering Technology DME-52884WA Student full name: I certify that the attached assessment is my own work and that any material drawn from other sources has been acknowledged. Copyright in assessments remains my property, however I grant permission to the Engineering Institute of Technology (EIT) to make copies of assessments for assessment, review and/or record keeping purposes. I note that the EIT reserves the right to check my assessment for plagiarism. Should the reproduction of all or part of an assessment be required by the EIT for any purpose other than those mentioned above, appropriate authorisation will be sought from me on the relevant form. Please place a tick () in the box below to indicate that you have read, understood, and certify the above statement. Please include this page in/with your submission. Any electronic responses to this submission will be sent to your Moodle account. AGREEMENT DATE: Marks (%) Satisfactory / Not Satisfactory Assessor: Date: Overall feedback: Guidelines for Students How is this module assessed? After completion of this assessment, you will be given a result of ‘Satisfactory’ or ‘Not Satisfactory’. The assessor will give you feedback via Moodle and you will have an opportunity to submit additional evidence, if you have received a ‘Not Satisfactory’ result. You will be allowed one (1) opportunity to resubmit the same assessment task, if required. For a ‘Satisfactory’ result in this assessment, all questions must be answered to a satisfactory standard and you must achieve an overall mark of 60% or above. Once all assessment tasks for this module have been completed, you will be given a final module result of ‘Competent’ or ‘Not Yet Competent’. If you are deemed ‘Not Yet Competent’ in a module after all resubmission attempts, you will be required to re-sit the module. How is this assessment task assessed? For a result of ‘Satisfactory’ in this assessment task, all module assessment criteria (as indicated on page 4) must be completed to a satisfactory standard. Where a critical question is identified, you must receive a mark of 100% for these questions before a ‘satisfactory’ result can be awarded, regardless of the overall mark achieved. At Advanced Diploma level, a ‘satisfactory’ standard, as stipulated by the Australian Qualifications Framework, means that you will demonstrate the application of knowledge and skills: · with depth in areas of specialisation, in contexts subject to change · with initiative and judgment in planning, design, technical or management functions with some direction · to adapt a range of fundamental principles and complex techniques to known and unknown situations · across a broad range of technical or management functions with accountability for personal outputs · personal and team outcomes within broad parameters Assessors also make decisions based on the following considerations: · all parts of this assessment have been completed to a standard that satisfactorily meets the requirements set out in the assessment criteria (as per the module outline). · the assessment evidence provided is the student’s own work, except as appropriately acknowledged by the use of referencing. · the evidence is recent and the student’s knowledge is up-to-date Assessment Instructions: 1. You must answer ALL questions. 1. Please ensure you complete your answers in a blue font (not red or black). 1. The best marks can be earned by giving concise, brief answers that address the questions. 1. You must reference all content used from other sources including course materials, slides, diagrams, etc. Do not directly copy and paste from course materials or any other resources. Refer to the referencing section of the EIT eLibrary on Moodle for referencing guides. 1. Use this document for completing your answers by typing the answers after each question without deleting the question. Make sure that you preserve the original question number format. 1. Do not add extra pictures, etc. as annexures; instead, paste them directly into this answer sheet. Hand-drawn sketches can be inserted after scanning but please ensure that the file size does not become big (more than 10 MB). You must refer to all diagrams and pictures, etc. that you have drawn or pasted in. 1. When saving your document (must be Word format), ensure you include your name in the title: COURSECODE_MODULE#_ASSESSMENTTYPE_VERSION#_YOURNAME E.g. DM_ M6_WrittenAssessment_v1.2_JohnSmith Module no. and name: DMEHYD609: Hydraulics Assessment type: Written Total marks: 120 Critical questions: Q1 and Q10. All critical questions must be answered correctly. Assessment Points: · You must submit this assessment along with the practical component. · You must answer all questions. Q1 This is a CRITICAL QUESTION. You must achieve 100% on this question. a) What does pressure refer to in relation to hydrostatics? b) What is it dependent on? (2 marks) A1 Student answer F1 Assessor feedback: (marks awarded) Q2 a) Figure below contains a depiction of an embossing press in which a single-acting cylinder is used for ejecting the processed parts. With the help of circuit diagrams, describe how this cylinder can be activated using 2/2 and 3/2 valves. b) Compare the two diagrams with regard to extension and retraction of the piston rod and draw your conclusions. c) Calculate the advancing pressure (p) for a piston rod whose diameter d = 60 mm and with a load weight F = 5 kN. Ignore the resistances for this calculation. (6 marks) A2 Student answer F2 Assessor feedback: (marks awarded) Q3 a) If 1kg of mass is taken to the moon, would it still have a mass of 1 kg on the moon? b) If the absolute pressure in a hydraulic system is 800 kPa, what is the gauge pressure? c) What is meant by the viscosity of a hydraulic fluid? d) For which two important hydrostatic principles is Pascal’s law used? e) Why is pressure lost when there is flow along a pipe? Where does the pressure go? (5 marks) A3 Student answer F3 Assessor feedback: (marks awarded) Q4 a) What is the function of a directional control valve? b) What are the three main types of pressure control valves? (2 marks) A4 Student answer F4 Assessor feedback: (marks awarded) Q5 a) A 4 kW motor is driving an oil pump with an efficiency of 95% down a 10 mm diameter pipe. If the velocity of the fluid down the pipe is 1.8 m/s. Calculate the flow rate that the pump would deliver. b) What is the pressure that the pump can deliver? c) If a 25 mm bore hydraulic cylinder is connected to the pipe, what would the forward stroke speed of the cylinder be? d) The viscosity of the oil is v = 0.00001 m2/s. Is the flow in the pipe laminar or turbulent? (4 marks) A5 Student answer F5 Assessor feedback: (marks awarded) Q6 a) What happens during transitional flow? b) What are the parameters required to determine Reynold’s number? (4 marks) A6 Student answer F6 Assessor feedback: (marks awarded) Q7 a) A double rod hydraulic cylinder with 50 mm diameter rod and a 100 mm diameter piston are shown in the figure, and 7000 kPa pressure is applied. A concrete wall stops the rod which prevents the piston from moving. Determine the force exerted on the wall by the piston. (2 marks) b) A hydraulic press has a ram of 25 cm diameter and a plunger of 4.0 cm diameter. Find the weight lifted by the hydraulic press when the force applied at the plunger is 400 N. (4 marks) (6 marks) A7 Student answer F7 Assessor feedback: (marks awarded) Q8 a) Explain Bernoulli’s Principle with regard to an aerofoil. (3 marks) b) The diameters of a pipe are 15 cm and 20 cm at sections 1 and 2 respectively. The velocity of water flowing through the pipe is 4 m/sec at section 1. Determine the discharge through the pipe and also the velocity of flow at section 2. (5 marks) (8 marks) A8 Student answer F8 Assessor feedback: (marks awarded) Q9 A pump delivers 40 litres/min to a 90 mm bore/30 mm rod cylinder to lift a load of 200 kg. a) What is the pressure exerted on the piston? b) What is the speed at which the load will be lifted? c) How much power is required to lift the load at this speed? (6 marks) A9 Student answer F9 Assessor feedback: (marks awarded) Q10 This is a CRITICAL QUESTION. You must achieve 100% on this question. a) What causes side loading in cylinders? b) How can it be minimized? (3 marks) A10 Student answer F10 Assessor feedback: (marks awarded) Q11 a) What is the basis for piston rod design? Explain the significance of area ratio. b) List 4 of the likely causes for slow or erratic motion of an actuator in a hydraulic equipment. (4 marks) A11 Student answer F11 Assessor feedback: (marks awarded) Q12 a) Give a graphic representation of the 6 different types of pressure control valves. (4 marks) b) The circuits below are an illustration of the working of a pressure reducing valve and a high-low system employing an unloading valve. Explain the operation of the valves. (8 marks) (12 marks) A12 Student answer F12 Assessor feedback: (marks awarded) Q13 In a direct acting pressure relief valve, 64 bar pressure is acting on the conical dart seating area and the dart is kept closed by a spring force of 50 kg opposing the pressure. a) Determine the bore diameter on the seat. b) What will the spring force be if a pressure of 3200 kPa is acting on diameter of 10 mm seating area? (3 marks) A13 Student answer F13 Assessor feedback: (marks awarded) Q14 Name 6 of the factors on which the designation of a directional control valve is normally based on. (3 marks) A14 Student answer F14 Assessor feedback: (marks awarded) Q15 a) Identify the actuation methods from the illustrated graphic. b) What are the key considerations in choosing the valve actuation method? (4 marks) A15 Student answer F15 Assessor feedback: (marks awarded) Q16 a) What is valve overlap? (2 marks) b) Why is some amount of valve overlap desirable? (1 mark) c) Define the term zero overlap. (2 marks) (5 marks) A16 Student answer F16 Assessor feedback: (marks awarded) Q17 a) Explain briefly the different valve configurations shown. (3 marks) 1) 2) 3) b) Name three typical applications in which Tandem centre spool configuration is used. (1.5 marks) c) What is the chief disadvantage associated with this configuration? (1.5 marks) (6 marks) A17 Student answer F17 Assessor feedback: (marks awarded) Q18 Explain in brief the working of pressure control valves. (3 marks) A18 Student answer F18 Assessor feedback: (marks awarded) Q19 a) List three of the primary causes for pressure surge in hydraulic systems. (2 marks) b) What is pressure override? (1 mark) c) Describe its effects on hydraulic components. (1 mark) (4 marks) A19 Student answer F19 Assessor feedback: (marks awarded) Q20 a) What is the main drawback with regard to the use of AC coils in proportional valves? (2 marks) b) Distinguish between force-controlled and stroke-controlled proportional solenoids. (3 marks) (5 marks) A20 Student answer F20 Assessor feedback: (marks awarded) Q21 a) What are proportional valves and where are they used? b) Name the different types of proportional valves. c) For which type of applications are Pilot-operated proportional pressure relief valves normally used? d) Describe in brief, the principle of working of a proportional flow control valve. (8 marks) A21 Student answer F21 Assessor feedback: (marks awarded) Q22 Explain the advantages associated with servo control using an example. (3 marks) A22 Student answer F22 Assessor feedback: (marks awarded) Q23 Describe the sequence of operations for the mechanical hydraulic servo system shown. (4 marks) A23 Student answer F23 Assessor feedback: (marks awarded) Q24 a) Name the common types of elements (4 fixed and 4 sensitive) used with pressure transducers. (2 marks) b) List some of the applications in which linear displacement transducers are used. (1.5 marks) c) What generates noise in amplifiers? (1.5 marks) (5 marks) A24 Student answer F24 Assessor feedback: (marks awarded) Q25 Consider the hydraulic lift system in the figure below, with 10 mm rod and 50 mm cylinder, used to lift a 500 kg load. a) A handpump is being used with a stroke of 7 cm3 per pump actuation. How many pump cycles would be required to lift the load 100 mm high? b) Assume you operate the hand pump at a speed of 0.3 Hz. How long would it take to lift the load 100 mm high? c) What is the work and power required from the pump operator? d) Assume now an electric motor is being used that pump at a rate of 3 litres / min. How long would it take to lift the load 100 mm? e) What is the work and power required from the electric motor? (5 marks) A25 Student answer F25 Assessor feedback: (marks awarded) END OF ASSESSMENT DME_DMEHYD609_WrittenAssessment_v1.1 50 mm 100 mm 70 bar 200 kg 30 mm 90 mm 40