Discussion
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- Question
What is the critical rotation speed in revolutions per second, for a ball mill of 1.2 m diameter charged with 70 mm dia balls?
Options- A. 0.5
- B. 1.0
- C. 2.76
- D. 0.66
- Correct Answer
- 0.66
- 1. In a roll crusher, both the rolls
Options- A. have the same diameter.
- B. are rotated towards each other.
- C. run either at the same or different speeds.
- D. all (a), (b) and (c). Discuss
- 2. Dry powdery solid materials are transported by a __________ conveyor.
Options- A. belt
- B. bucket
- C. screw
- D. none of these Discuss
- 3. A centrifugal filtration unit operating at a rotational speed of w has inner surface of the liquid (density ?L) located at a radial distance R from the axis of rotation. The thickness of the liquid film is ? and no cake is formed. The initial pressure drop during filtration is
Options- A. ½w2 . R2 . ?L
- B. ½w2 . ?2 . ?L
- C. ½w2 . ??L (2R + ?)
- D. ½w2 . R . ?L(R + 2?) Discuss
- 4. Solid particles of different densities are separated by
Options- A. filters
- B. thickness
- C. cyclones
- D. sorting classifier Discuss
- 5. Optimum ratio of operating speed to critical speed of a trommel is
Options- A. 0.33-0.45
- B. 1.33-1.45
- C. 0.5-2
- D. 1.5-2.5 Discuss
- 6. The cake resistance increases steadily with the time of filtration in a plate and frame filter employing constant __________ filtration.
Options- A. rate
- B. pressure
- C. both (a) & (b)
- D. neither (a) nor (b) Discuss
- 7. As particle size is reduced
Options- A. screening becomes progressively more difficult.
- B. screening becomes progressively easier.
- C. capacity and effectiveness of the screen is increased.
- D. none of these. Discuss
- 8. Percentage of drum submerged in the slurry in case of rotary drum filter is
Options- A. 3
- B. 30
- C. 85
- D. 25 Discuss
- 9. Critical speed of rotation, N (in rps - rotation per second) of a trammel is equal to (where, g = acceleration due to gravity = 9.81 m/sec2 and, r = radius of trammel, metre. )
Options- A.
- B.
- C.
- D.
Discuss
- 10. Which of the following is a continuous filter?
Options- A. Plate and frame filter
- B. Cartridge filter
- C. Shell and leaf filter
- D. None of these Discuss
Mechanical Operations problems
Search Results
Correct Answer: all (a), (b) and (c).
Correct Answer: screw
Correct Answer: ½w2 . ??L (2R + ?)
Correct Answer: sorting classifier
Correct Answer: 0.33-0.45
Correct Answer: both (a) & (b)
Correct Answer: screening becomes progressively more difficult.
Correct Answer: 30
Correct Answer:
Correct Answer: None of these
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