In a roll crusher, the specific power consumption and the production rate is affected by the_________________?

Related Mcqs:

1. Half the angle of nip, (α), for a roll crusher is given by (where, dr, dp and df are diameters of crushing rolls, feed particles and rolls gap respectively) ?

   A. cos α = (dr + dp)/(dr + df)
   B. cos α = (dr + df)/(dr + dp)
   C. tan α = (dr + dp)/(dr + df)
   D. sin α = (dr + dp)/(dr + df)

2. Horsepower required for a roll crusher is directly proportional to its__________________?

   A. Reduction ratio
   B. Capacity
   C. Both A. & B.
   D. Neither A. nor B.

3. In a roll crusher, both the rolls_________________?

   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.

4. The capacity of a gyratory crusher is ______________ that of a jaw crusher with the same gape, handling the same feed & for the same product size range.?

   A. Same as
   B. 2.5 times
   C. 5 times
   D. 10 times

5. Which of the following crushers can be considered as a combination of a jaw crusher and a roller crusher ?

   A. Rod mill
   B. Fluid energy mill
   C. Gyratory crusher
   D. Ball mill

6. According to Taggart’s rule for selecting between a gyratory crusher and a jaw crusher; the later should be used, if the hourly tonnage to be crushed divided by the square of the gape expressed in cm is less than_______________?

   A. 0.00184
   B. 0.0184
   C. 0.184
   D. 1.84

7. Energy consumption in a crusher decreases with increase in the________________________?

   A. Size of the product (at constant feed size)
   B. Capacity of the crushing machine
   C. Size of feed (at constant reduction ratio)
   D. All A., B. & C.

8. Which of the following relationships between co-efficient of friction (μ) between rock & roll and a (half of the angle of nip) of the particle to be crushed is correct ?

   A. μ > tan α
   B. μ ≥ tan α
   C. μ > tan 2α
   D. μ ≤ tan α

9. Size reduction of _____________ is accomplished in steam heated rollers and roll crushers?

   A. Resins
   B. Gums
   C. Hard rubber
   D. Waxes

10. Pick out the wrong statement pertaining to the roll crushers?

    A. Maximum feed size determines the required roll diameter
    B. For hard material’s crushing, the reduction ratio should not exceed 4
    C. Both the rolls run necessarily at the same speed
    D. Reduction ratio and differential roll speed affect production rate & energy consumed per unit
    of surface produced