Free Fluid Flow Operations MCQs with Answers

• A. Filtering
• B. All A., B. & C.
• C. Drying
• D. Washing

Explanation: A rotary drum vacuum filter uses vacuum during cake formation, cake washing, and cake drying zones.

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

Explanation: For the same gape, feed, and product-size range, a gyratory crusher has a capacity of about 2.5 times that of a jaw crusher.

• A. 1.5-2.5
• B. 1.33-1.45
• C. 0.5-2
• D. 0.33-0.45

Explanation: A trommel is normally operated well below its critical speed, with the operating-to-critical speed ratio commonly about 0.33 to 0.45.

• A. Both A. & B.
• B. Bulk density
• C. Lump size
• D. Neither A. nor B.

Explanation: Lump size determines the minimum practical belt width, while bulk density affects the mass capacity and therefore the required belt speed.

• A. Cutting
• B. Compression
• C. Attrition
• D. None of these

Explanation: Attrition produces fines by rubbing particles against one another or against a surface, making it suitable for soft, non-abrasive…

• A. Jaw crusher
• B. Toothed roll crusher
• C. Impact crusher
• D. Cone crusher

Explanation: A cone crusher is commonly used as a secondary crusher for hard and tough stones after primary size reduction.

• A. Is suitable for mixing low viscosity liquids
• B. Produces axial flow
• C. Moves at very high speed
• D. None of these

Explanation: Paddle agitators are low-speed mixers suitable for low- to moderately viscous liquids.

• A. Ball mill
• B. Jaw crusher
• C. Fluid energy mill
• D. Rod mill

Explanation: Jaw crushers accept large lumps, commonly feed sizes of about 25 cm or more, and reduce them by compression.

• A. Blake-Plummer equation
• B. Leva's equation
• C. Kozeny-Carman equation
• D. None of these

Explanation: Flow through a deposited filter cake is treated as laminar flow through a porous medium, for which the Kozeny-Carman equation relates…

• A. Cake resistance decreases
• B. Filter medium resistance increases
• C. Filter medium resistance decreases
• D. All the resistances are constant

Explanation: In ordinary cake washing, the cake and filter-medium structure is assumed unchanged, so their hydraulic resistances remain constant.

• A. Compression
• B. Attrition
• C. Impact
• D. Cutting

Explanation: Coarse crushing of hard solids is best performed by compression, as in jaw and gyratory crushers.

• A. P/m = K/ √Dp
• B. P/m = K . ln D̅ sa/D̅ sb
• C. P/m = K . (1/ D̅ sb - 1/D̅ sa)
• D. None of these

Explanation: Rittinger's law states that energy or power per unit mass is proportional to the new surface area produced.

• A. Pebble
• B. Compartment
• C. Cage
• D. Tube

Explanation: Pebble, compartment, and tube mills are revolving mills in which the shell rotates.

• A. A batch filter
• B. Not suitable, if the liquid is the main product
• C. Having prohibitively high maintenance cost
• D. Not suitable for wide range of materials under varying operating conditions of cake thickness
• E. and pressure

Explanation: A filter press operates cyclically: filling, cake formation, washing if required, and cake discharge, so it is a batch filter.

• A. Roller crusher
• B. Hammer crusher
• C. Impact mill
• D. Fluid energy mill

Explanation: Roller mills apply compression and shear between rotating rolls, making them suitable for reducing wheat kernels to flour.

• A. Mixer-extruder
• B. Pug mill
• C. Banbury mixer
• D. Muller mixer

Explanation: A pug mill is designed to continuously mix and knead moist or plastic solids, so it can combine molten ammonium nitrate with ground…

• A. Grinder
• B. Crusher
• C. Ultrafine grinder
• D. Cutter

Explanation: A fluid energy mill uses high-velocity gas jets to produce intense particle-to-particle attrition, commonly yielding micron-sized powders.

• A. Gyratory crusher
• B. Toothed roll crusher
• C. Ball mill
• D. Tube mill

Explanation: A gyratory crusher is designed for primary crushing and can accept large, very hard lumps continuously under compression.

• A. Belt
• B. Screw
• C. Bucket
• D. None of these

Explanation: Screw conveyors are well suited to moving dry powdery solids over short or moderate distances in an enclosed trough.

• A. Apron conveyor
• B. Belt conveyor
• C. Screw conveyor
• D. Pneumatic conveyor

Explanation: A screw conveyor can move sticky or sluggish material because the rotating screw positively pushes it through an enclosed trough.