Engineering Questions with Answers - Multiple Choice Questions

Mechanical Operations MCQ’s – Thickeners

1 - Question

When washing is difficult, the cake can be ________
a) Charged
b) Discharged
c) Compressed
d) Decompressed

View Answer

Answer: b
Explanation: When washing becomes difficult, the unwashed cake may be discharged and then mixed with the wash liquid to form a fresh slurry.

2 - Question

When cake is difficult to separate then, a ________ is employed.
a) High pressure
b) String discharge
c) Extra force
d) Compressor

View Answer

Answer: b
Explanation: When the cake is difficult to remove or when it is desirable to deliver it intact, a string discharge is employed.

3 - Question

Careful adjustment of the doctor knife is essential.
a) True
b) False

View Answer

Answer: a
Explanation: There is an essential need to make adjustment in the doctor’s knife, for it is set too close to the drum the cloth may get damaged.

4 - Question

What is the thickness range for a cake of rotary drum?
a) 50 to 60 mm
b) 3 to 100 mm
c) 100 to 200 mm
d) 500 to 1000 mm

View Answer

Answer: b
Explanation: Cake of varying thickness can be built up by the altering speed of rotation of the filter, the usual range is given as 3 to 100 mm.

5 - Question

The rotary disc consists of the number of ______ filter mounted.
a) Rectangular
b) Circular
c) Triangular
d) Spherical

View Answer

Answer: b
Explanation: The rotary disc filter consists of the number of circular leaves mounted on a heavy horizontal tubular shaft.

6 - Question

A rotary drum filter is _______
a) Continuous vacuum filter
b) Continuous pressure filter
c) Discontinuous pressure filter
d) Discontinuous vacuum filter

View Answer

Answer: a
Explanation: The rotary drum is a continuous type of vacuum filter, the vacuum is applied to suck the cake from the slurry feed.

7 - Question

Filter aids are added to the slurry prior to filtration in order to form _______
a) Compact cakes of low porosity
b) Cakes of increased porosity
c) Crystalline cakes
d) Baked cake

View Answer

Answer: b
Explanation: Filter aids are the media that are used to increase the rate of cake formation and it also makes the cake porous thus increasing efficiency.

8 - Question

In a filter bed, the liquid flow ________
a) Is laminar
b) Is turbulent
c) Is between laminar and turbulent
d) Cannot be predicted

View Answer

Answer: a
Explanation: The flow in the filter bed is generally kept laminar because as the flow becomes turbulent the formation of eddies take place and result in choking of cake.

9 - Question

 In S.I. system, the unit of filter medium resistance is _______
a) kg /m2S
b) m2/S
c) kg /m3S
d) m-1

View Answer

Answer: d
Explanation: As per the formulation and the unit basis the filter medium resistance has the unit of meter inverse i.e. m-1.

10 - Question

The moore filter, operates under _______
a) High pressure
b) Low pressure
c) High head
d) Low head

View Answer

Answer: b
Explanation: The filter operates under reduced pressure, so that pressure difference is limited and hot liquid cannot be filtered.

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