Mechanical Engineering Quiz
33 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What type of valve is primarily responsible for regulating steam flow in a turbine governing system?

  • Overspeed governor
  • Sentinel valve (correct)
  • Governor valve
  • Hand speed control
  • What component contacts the shaft to prevent axial movement in turbine thrust bearings?

  • Labyrinth
  • Collar
  • Shaft sleeve
  • Shroud (correct)
  • What is a common reason for replacing shaft sealing carbon glands?

  • Material fatigue
  • Overheating
  • Erosion (correct)
  • Contamination
  • Which principle is most commonly utilized by steam turbine governing systems?

    <p>Lever principle</p> Signup and view all the answers

    In an impulse turbine, what happens to the steam pressure as it passes through the nozzles?

    <p>Pressure drops</p> Signup and view all the answers

    Which material is commonly used as a solid lubricant?

    <p>Molybdenum disulfide</p> Signup and view all the answers

    In which situation is grease not a suitable lubricant?

    <p>When corrosion protection is essential</p> Signup and view all the answers

    What indicates an oil's capability to support a load?

    <p>Viscosity</p> Signup and view all the answers

    What has the greatest impact on the viscosity of lubrication oil?

    <p>Temperature</p> Signup and view all the answers

    Which type of grease is the most commonly used and cost-effective?

    <p>Lithium based</p> Signup and view all the answers

    What is the correct action to take with the casing vent valve on a standby pump?

    <p>Close the casing vent valve</p> Signup and view all the answers

    Which configuration of valves is typical for a positive displacement standby pump?

    <p>Suction valve closed and discharge valve open</p> Signup and view all the answers

    Cryogenic pumps primarily operate at which condition?

    <p>Extremely low temperatures</p> Signup and view all the answers

    What is the primary function of a circulating pump?

    <p>To circulate fluid through a heat exchange system</p> Signup and view all the answers

    In which scenario would a multi-stage pump be preferred?

    <p>When the lift height is significant</p> Signup and view all the answers

    What is the ideal application for turbine pumps?

    <p>High capacity at high pressure</p> Signup and view all the answers

    Wear rings on an impeller are typically secured by what method?

    <p>Set screws or threading</p> Signup and view all the answers

    Which materials are most commonly used for constructing wear rings?

    <p>Bronze and cast iron</p> Signup and view all the answers

    What is one possible cause of a pump not functioning properly?

    <p>The impeller is plugged</p> Signup and view all the answers

    In which setting are compressed air machinery most likely used?

    <p>Coal mines</p> Signup and view all the answers

    What occurs to kinetic energy in a centrifugal compressor?

    <p>It is converted to potential energy in the volute</p> Signup and view all the answers

    Which type of air compressor prioritizes volume over pressure?

    <p>Rotary lobe compressor</p> Signup and view all the answers

    What type of air compressors are categorized as positive displacement?

    <p>Rotary compressors</p> Signup and view all the answers

    What is a characteristic of single stage reciprocating air compressors?

    <p>They provide a smooth discharge delivery</p> Signup and view all the answers

    Higher gearing is typically used in which type of compressor?

    <p>Rotary lobe units</p> Signup and view all the answers

    What do compressor unloaders do?

    <p>They can keep the suction valve open</p> Signup and view all the answers

    What is used to reduce air temperature between stages in an air compression system?

    <p>An intercooler</p> Signup and view all the answers

    What mechanism is crucial for lubricant efficacy in a cylinder where pistons move?

    <p>Sealing</p> Signup and view all the answers

    What is the minimum pipe size in mm for the valve fittings on a steam boiler according to ASME code?

    <p>51</p> Signup and view all the answers

    Why is a stop valve required at each boiler outlet in a multiple steam boiler heating system?

    <p>To allow boiler isolation from the system</p> Signup and view all the answers

    What type of valves are typically used as boiler outlet valves due to their low resistance to flow?

    <p>Gate valves</p> Signup and view all the answers

    What characteristic of an outside screw and yoke valve differentiates it from others?

    <p>It readily shows its operating position</p> Signup and view all the answers

    How much of a turn is required to operate the quick closing valves on the water gauge?

    <p>Half a turn</p> Signup and view all the answers

    Study Notes

    Turbine Components and Operation

    • The sentinel valve functions as a safety device in steam systems, preventing overpressure situations.
    • Turbine thrust bearings restrict axial movement of the spindle by contacting the shroud on the shaft.
    • Shaft sealing carbon glands require regular replacement due to erosion, typically on a monthly basis.
    • The majority of steam turbine governing systems employ the pneumatic system principle.

    Reaction Turbines

    • Reaction turbines utilize a pressure drop through both moving and stationary blades for energy conversion.
    • Velocity increases occur in the fixed blading of reaction turbines, conducive to efficient steam usage.

    Impulse Turbines

    • In impulse turbines, steam pressure is reduced in the nozzles, leading to increased velocity through the blades.
    • This turbine type ensures that every set of blades experiences a pressure drop.

    Pump Types and Operations

    • A positive displacement standby pump typically has the suction valve closed and the discharge valve open during operation.
    • Cryogenic material pumps usually operate as staged units to handle extremely low temperatures.
    • A multi-stage pump is necessary for great lift but does not necessarily increase the pumped volume.

    Pump Maintenance and Components

    • Wear rings on impellers protect against wear and reduce maintenance costs.
    • Stuffing boxes help manage leakage when the casing is under pressure, typically filled with packing.

    Compressed Air Systems

    • Compressed air is extensively used in agricultural applications and for driving tools in various industries.
    • In centrifugal compressors, kinetic energy converts to potential energy within the volute and diffuser.
    • Positive displacement compressors can be rotary or reciprocating and are adept at producing high discharge pressures.

    Lubrication and Oil Properties

    • Grease is inappropriate as a lubricant in applications requiring significant cooling or when moisture is prevalent.
    • The property indicating an oil's load-bearing capacity is viscosity, with a lower viscosity index signifying greater viscosity fluctuations with temperature changes.
    • High fluid friction arises from oils with a viscosity rating of 100 or higher.

    Boiler Systems

    • Each steam boiler must incorporate water gauge glasses connected through a minimum of 51 mm piping.
    • Multiple boiler systems require stop valves to facilitate isolation from the system and ensure flow control, typically utilizing gate or globe valves.
    • Quick-closing valves in water gauges necessitate only a quarter turn for complete closure or opening.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    Description

    Test your knowledge of mechanical systems with this quiz focused on governors, thrust bearings, and shaft sealing. Each question challenges your understanding of key concepts in mechanical engineering. Perfect for students and professionals alike!

    More Like This

    Use Quizgecko on...
    Browser
    Browser