Particle size range in which dust catcher (gravity settling chamber) works most effectively and efficiently is ______________ microns?

Related Mcqs:

1. A suspension of glass beads in ethylene glycol has a hindered settling velocity of 1.7 mm/s, while the terminal settling velocity of a single glass bead in ethylene glycol is 17 mm/s. If the Richardson-Zaki hindered settling index is 4.5, the volume fraction of solids in the suspension is_____________?

   A. 0.1
   B. 0.4
   C. 0.6
   D. None of these

2. A 30% (by volume) suspension of spherical sand particles in a viscous oil has a hindered settling velocity of 4.44 μm/s. If the Richardson Zaki hindered settling index is 4.5, then the terminal velocity of a sand grain is_________________?

   A. 0.90 μm/s
   B. 1 μm/s
   C. 22.1 μm/s
   D. 0.02 μm/s

3. Sphericity for a non-spherical particle is given by (where, V and S are volume and surface area respectively of one particle. and, D = equivalent diameter of particle)?

   A. 6.V/D.S
   B. V/6D.S
   C. D.S/V
   D. V/D.S

4. Sphericity is the ratio of the surface area of a spherical particle having the same volume as the particle to the surface area of the particle. Which of the following has the maximum value of sphericity ?

   A. Sphere
   B. Cube
   C. Cylinder (L/D = 1)
   D. Raschig rings

5. Dust collection efficiency of electrostatic precipitator can be as high as 99.9%. Maximum temperature and pressure of dust laden gas that can be cleaned in an electrostatic precipitator is respectively ?

   A. 200°C and 5 atm
   B. 1000°C and 10 atm
   C. 500°C and 50 atm
   D. 1000°C and 500 atm

6. In the cyclone separator used for separation of dust from dust laden gas, the gas ?

   A. Enters the cyclone from the top
   B. Is admitted tangentially at high velocity
   C. Develops a helical motion inside the chamber
   D. Both B. and C.

7. Metallic wire mesh is used as a filtering medium for the separation of dust from dust laden gas in case of a/an________________?

   A. Air filter
   B. Bag filter
   C. Venturi scrubber
   D. Hydrocyclones

8. Gravity settling process is not involved in the working of a________________?

   A. Hydrocyclone
   B. Classifier
   C. Dorr-thickener
   D. Sedimentation tank

9. The most suitable equipment for removing the fine dust particle (< 1 micron dia.) from air below its dew point will be a/an______________?

   A. Bag filter
   B. Electrostatic precipitator
   C. Cyclone separator
   D. Wet scrubber

10. The resistance offered by the filter used in a bag filter is proportional to (where, c = dust concentration, and s = particle size)?

    A. c/s
    B. s/c
    C. s . c
    D. 1/s . c