Engineering Questions with Answers - Multiple Choice Questions

# Mechanical Operations MCQ’s – Cyclone Separators

1 - Question

What is the speed of a horizontal belt filter?
a) 0.05 m/s
b) 0.1 m/s
c) 0.5 m/s
d) 10 m/s

Explanation: The speed of the belt is about 0.05 m/s and the distance over which slurry is applied is so adjusted to produce a suitable thickness.

2 - Question

In liquid-liquid operations, centrifugal force is employed in
a) Settling
b) Filtration
c) Sedimentation
d) Both setting and filtration

Explanation: In liquid-liquid operations, centrifugal force is employed in both settling and filtration, in both cases it replaces weaker force of gravity.

3 - Question

The prayon continuous filter, filters a surface of about ________
a) 1 to 20 m2
b) 2 to 40 m2
c) 30 to 40 m2
d) 100 to 150 m2

Explanation: Prayon filter is made in five sizes providing filtering surfaces from about 2 to 40 m2 , it consists of a number of horizontal cells held in rotating frame.

4 - Question

Prayon filter has _______ percent of effective area.
a) 85
b) 48
c) 47
d) 50

Explanation: A large filtering area, up to 85 percent of which is effective at any instant, low operating and maintenance cost and simple cloth replacement.

5 - Question

Any rotating machine in which centrifugal force is applied is called as _______
a) Mixer
b) Rotator
c) Centrifuge
d) Gravitate

Explanation: Any rotating machine in which the centrifugal force is applied to achieve a phase separation is called as a centrifuge, it consists of a rotor bowl and a drive shaft.

6 - Question

The following equation represents the _______
F=0.000341 WrN2
a) Magnitude of gravity
b) Magnitude of Centrifuge
c) Force of inertia
d) Force of tangent

Explanation: Magnitude of centrifugal force is given by the above equation, where F is force developed in lb, W I sweight of rotating assembly and r is radius.

7 - Question

What does the following equation represents?

4.11*10-9 N2 Db2 ρm

b) Stress force
c) Force of inertia
d) Force of tangent

Explanation: Stress (SS) in a centrifugal bowl is given by the above equation, where Db is the diameter of the bowl, N is the rotations and p is the density.

8 - Question

Calculate F, if weight of assembly is 100 lb. and 5 ft. in radius having 20 rpm speed?
a) 3.41
b) 5.21
c) 6.82
d) 2.323

Explanation: As we know that F = 0.000341 WrN2 = 0.000341*100*5*20 = 3.41 lb.

9 - Question

Calculate Ss, if Diameter is given as 10 inches and has 200 rpm also consider water as medium?
a) 0.005
b) 0.00822
c) 0.00026
d) 0.0058

Explanation: We already know that density of water is 1000 kg/m3, so 4.11*(10-9)*10*200 = 0.0082 p.s.i. i.e. self-stress Ss.

10 - Question

The speed at which frequency of rotation matches the natural frequency is called ____
a) Final speed
b) Optimum speed
c) Critical speed
d) Operating speed