Utility Machinery exam (MDM 301) from BUTEX's 2024 Level-3 Term-I finals. Covers boiler mountings with heat balance sheets, summer air conditioning block diagrams, reciprocating compressors, refrigerant properties with ice plant numericals, and alternator phasors.
Level-3 Term-I, Final Exám-2024
Subject: Utility Machinery (Code: MDM 301)
Time: 3.0 Hrs. Full Marks: 72
(Use separate answer script for Part: A and Part: B)
(All parts of a question must be answered consecutively)
Part: A
(Answer any three questions)
1. (a) Draw a schematic diagram of a boiler plant with accessories.
(b) State the function of the following mountings:
(i) Safety valve (ii) Pressure gauge (iii) Water level indicator (iv) Steam stop valve.
(c) Draw the heat balance sheet of a boiler.
[4+4+4=12]
2. (a) Explain with a block diagram the working of a summer air conditioner. Describe the function of each component.
(b) Explain the significance of boiler draught in the efficient operation of boilers.
[8+4=12]
3. (a) List any three differences between axial flow compressor and centrifugal compressor.
(b) Explain the working principle of a single-stage reciprocating air compressor with the help of a neat sketch.
(c) When is multi-stage compression used for air? What are its advantages?
[3+6+3=12]
4. (a) State the properties of a good refrigerant.
(b) An ice plant produces 10 tonnes of ice per day at 0°C using water at room temperature of 20°C. Estimate the power rating of the compressor-motor, if the C.O.P of the plant is 2.5 and overall electro-mechanical efficiency is 90%.
(c) Define the following terms: (i) Coefficient of performance (ii) Tonne of refrigeration.