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Chemical Engineering :: Mechanical Operations

  1. Carbon black is pulverised in a

  2. A.
    hammer crusher
    B.
    ball mill
    C.
    roll crusher
    D.
    gyratory crusher

  3. The most efficient equipment for the removal of sub-micronic dust particles from blast furnace gas is the

  4. A.
    venturi atomiser
    B.
    gravity settling chamber
    C.
    electro-static precipitator
    D.
    cyclone separator

  5. The filtrate flow rate in constant pressure filtration

  6. A.
    continuously increases.
    B.
    continuously decreases.
    C.
    remains constant throughout.
    D.
    may increase or decrease ; depends on the pressure.

  7. Theoretical capacity of crushing rolls in tons/hr is given by (where, V = peripherial velocity, m/sec. W = width of rolls, m Dr = distance between rolls ρ = density of material to be crushed, kg/m3 here, VN.D where, N = speed of the rolls in rotation per second (rps) D = diameter of rolls, m)

  8. A.
    3.6 V.W.Dr
    B.
    3.6 V.W. ρ
    C.
    3.6 W.Dr
    D.
    3.6 V.W.Dr

  9. Vibrating screens are used for handling large tonnages of materials. The vibrating motion is imparted to the screening surface by means of

  10. A.
    electromagnets
    B.
    cams or eccentric shafts
    C.
    unblanced fly wheels
    D.
    either (a), (b) or (c).

  11. The inlet pressure in a constant rate filtration

  12. A.
    increases continuously
    B.
    decreases gradually
    C.
    remains constant
    D.
    none of these

  13. Size reduction of moulding powders, waxes, resins & gums are done in a __________ mill.

  14. A.
    cage
    B.
    hammer
    C.
    both (a) & (b)
    D.
    id) neither (a) nor (b)

  15. Particle size range in which dust catcher (gravity settling chamber) works most effectively and efficiently is __________ microns.

  16. A.
    < 5
    B.
    10 to 25
    C.
    < 74
    D.
    > 1000

  17. __________ centrifuge is the most suitable for separation of non-friable crystals.

  18. A.
    Tubular bowl
    B.
    Disc-bowl
    C.
    Perforated horizontal basket continuous
    D.
    Suspended batch basket

  19. For benefication of iron ore, the most commonly used method is

  20. A.
    flocculation.
    B.
    froth floatation.
    C.
    jigging & tabling.
    D.
    none of these.