Food Processing Unit Operations Multiple Choice Questions on “Drying Equipments”.
1. Which of the following dryer is used for pureed raw ingredients that are dried at relatively low temperatures over rotating?
a) Fluidized bed dryer
b) Drum dryer
c) Cabinet tray dryer
d) Pneumatic dryer
Answer: b
Clarification: In the drum dryer, the pureed raw ingredients are dried at low temperatures over rotating. The additional advantage of this drier is that product is milled to produce powder or flakes form.
2. Which of the following dryer is used to produce powder from the solution?
a) Spray dryer
b) Cabinet tray dryer
c) Pneumatic dryer
d) Fluidized bed dryer
Answer: a
Clarification: Spray dyer is used to produce powder from the solution. It dries the solution stream and separates the solute and evaporates the solvent and forms vapor. The solid particles are collected in a cyclone or drum.
3. Who invented spray dryer?
a) Samuel Percy
b) Fritz Winkler
c) John A
d) Jacques-Arsened’Arsonva
Answer: a
Clarification: Samuel Percy invented spray dryer. Fritz Winkler invented fluidized bed dryer. John A invented drum dryer. Jacques-Arsened’Arsonva invented freeze dryer.
4. What is the alternative name for batch-in-bin dryer?
a) Flat bed dryer
b) Cabinet tray dryer
c) Pneumatic dryer
d) Fluidized bed dryer
Answer: a
Clarification: Batch-in-bin dryer is also known as flat bed dyer. Its capacity is of 1-3 tons per day with 6-12 hours of drying times. The batch-in-bin dryer is easy to construct and is inexpensive and simple to operate and require unskilled labor.
5. What is full form of LSU dryer?
a) Louisiana State University dryer
b) Low simple universal dryer
c) Low and slow unit dryer
d) Level steady unit dryer
Answer: a
Clarification: In Louisiana State University dryer, the drying section contains vertical compartment across which rows of air channels are fitted. Alternate rows are closedwhere the moving stream of grain from the top descends thus providing considerable mixing.
6. Which of the following statements about LSU dryer are correct?
Statement 1: LSU dryer is mainly used to dry the grains.
Statement 2: LSU is a continuous flow mixing type of dryer.
a) True, False
b) True, True
c) False, True
d) False, False
Answer: b
Clarification: LSU is a continuous flow mixing type of dryer. LSU dryer is mainly used to dry the grains. It is popular in India and USA. The capital investment is high. The recommended air flow rate is 60-70m3/ min/ ton.
7. What does Fritz Winkler invented?
a) Fluidized bed dryer
b) Drum dryer
c) Spray dryer
d) Freeze dryer
Answer: a
Clarification:Samuel Percy invented spray dryer. Fritz Winkler invented fluidized bed dryer. John A invented drum dryer. Jacques-Arsened’Arsonva invented freeze dryer.
8. Which dryer is used to dry the material almost instantaneously in a turbulent stream of hot air?
a) Fluidized bed dryer
b) Drum dryer
c) Cabinet tray dryer
d) Pneumatic dryer
Answer: d
Clarification: In pneumatic dryer, the material is dried almost instantaneously in a turbulent stream of hot air. This can also acts as conveyor system. It is applicable to powdered, granular, and flaky materials.
9. Which of the following dryer is the convectional drying equipment with enclosed insulated chambers?
a) Fluidized bed dryer
b) Drum dryer
c) Cabinet tray dryer
d) Pneumatic dryer
Answer: c
Clarification: Cabinet tray dryer is conventional drying equipment with enclosed insulated chambers. The trays are placed on top of each other in a trolley. The mode of heat transfer is forced convention.
10. What type of dryer is used for the drying of substances which are hygroscopic?
a) Fluidized bed dryer
b) Drum dryer
c) Cabinet tray dryer
d) Vacuum dryer
Answer: d
Clarification: Vacuum Tray dryer is the most commonly used batch dryer. Vacuum Tray Dryer is used for drying of hygroscopic substances and heat sensitive materials, which are dried to very low residual moisture content level.