# Solve the following (each for 2 marks)

Mechanics

Feb 22, 2014 (4 years and 4 months ago)

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Chapter
-
1.
INTRODUCTION

Solve the following

(each

for 2
marks)

1)

Define electro
-
osmosis.

2)
State the application of electrodialysis
.

3
)

Why size reduction is required in an industry?

4
) Give the principle of sedimentation and filtration.

5
) N
ame

two mechanical operations used for solid
-
liquid separation
.

6
Define

Mechanical operations. Give any two examples.

7) List out the Mechanical operations used in sugar industry.

8 List the mechanical operations in water treatment plant.

9) Define
Unit Operation.

Attempt the following

(
each for
4 marks)

1.

With

neat sketch explain desalination operation.

2.

State

the principle of decanter and explain it’s application.

3.

Differentiate

between filtration and sedimentation.

4.

State

specifi
c principle involved in following operation:

i) Decantation ii)
Sedimentation.

5

Differentiate

between Sedimentation

and centrifuge (two points).

6
)
Differentiate

between filtration &
sedimentation. (2

points)

7
) How desalination of sea water is carried
out?

8) Give the classification of unit operation.

9) Define

1) Mixing 2) Sedimentation.

2. SIZE REUCTION

Attempt the following

(
each for
2 marks)

1)
Name the equip
ment in which size reduction is brought about by compression.

2)List the
type of size reducing equip
ment used in
chemical i
ndustry.

3) Define critical
speed of a ball mill
.

4)What is approximate size

of product obtain from a crusher and grinder.

5) Define cut diameter
.

6)
Define centrifuging of a ball mill
.

7)Write down the expression for critical speed of ball mill, and explain the term involved.

8) State
K
ick’s law
.

9) Give

wet grinding
in ball mill
.

10) Define cut diameter. What is its approximate
value?

11) State Rittinger’s law.

12)
State

the principle of size reduction by crushing

13)
List

any four types of size
reducing equipment
.

14) Define cut diameter. H
ow oversize and undersize fraction are
denoted?

15) Why crushing efficiency is always
less?

16) Define work index.

Attempt the following

(
e
ach for
4

marks)

1)
State Ritt
i
nger’s Law, write its equation and explain the term involved.

2) Differentiate black and dodge crusher and following point
.

a
)

Pivotation

of movable jaw

b
)

C
hance of blocking of the equipment and reason for it.

3
)Define angle and nip and draw
the sketch indicating the same.

4
)Draw a neat diagram

of a hammer mill and describe its working.

5) Classify the different size reduction equipment used
.
Write its principle and give

one example
of
each
.

6
)What should be the diameter of a set of roll to take feed of size equipment to

38mm sphere and
crush them to 12mm. The
coefficient of friction

is 0.35
.

8
)
Find the operating speed of the ball mill from the following data:

Diameter of ball mill

= 500mm

Diameter of ball

= 50mm

Operating speed of the mill is 35% of critical speed
.

14)Draw the diagram of a black jaw crusher and name the parts.

16)Give various principles by which size reduction is done.
Give example of each
.

17)Find out the critical spee
d of the ball using following data.

Diameter of ball mill = 450mm

Diameter of ball = 25mm

18)A certain set of crushing rolls has rolls of 1000mm diameter by 375mm. Width of Face. They
are set so that the crushing

surface are 12mm apart at the narrowest Point . the angle of nip is 30
0
What is the m
aximum permissible size of f
eed.

23)Derive an expression for calculating the critical speed of a ball mill.

26
) For crushing rolls derive equ
ation cosα

=

(r

+

d)

/

(r

+

R).

2
7
) A crushing roll 1m in dia. Are set so that crushing surface are 12.5 mm apart and angle of nip is
31°.What is the maximum size of particles which should be fed in the rolls ?

2
8
)

Draw neat diagram of open circuit and close circuit grinding .

29
) Derive an expression for calculating the critical speed of a ball mill.

3
0
)
Write

expression for calculating the critical speed of a ball mill and state the meaning of variable in it .

3
1
) Derive expression for calculating angle of nip.

Attempt the following

(
each for
8 marks)

1
)Draw a labelled diagram of an open circuit and closed circuit grinding

and describe their relative

2
) a
) For crushing rolls derive the equation cos ά = (r + d ) / (r + R ).

b) A crushing rolls 1 meter in diameter are
seeing

so that

the crushing surfaces

are 12.5 mm part &

angle

of nip is 31°, what is the maximum size of particles which should be fed in the rolls.

3
)

Explain principle
,
construction and working of ball mill
.

4) Derive an expression for calculating critical speed of ball mill. Elaborate the concept o
f critical speed

with suitable example.

5) Calculate the operating speed of ball mill from following dat
e
:

i) Dia. Of ball mill = 675 mm

ii)Dia. of Ball = 55 mm

if i) Operating speed is 75% less than critical speed

ii) Operating speed is
50% less than critical speed.

6) What is the power required in kW to crush 100 ton/h of limestone if 80 % of the feed passes a 2’ screen
and 80 % of the product passes through a 1/8” screen.?

7) It is required to crush 350 T/h of ore. The range of feed siz
e is that 80% of the feed passes through an
opening of 18’’. The product is such that 80% of the product passes through an opening of 4”. What types of
crusher may be used. Estimate the power consumption per ton of feed.
(Assume

work
index 12.84
)

8) A
material is crushed in jaw crusher and avg. size of particle reduced from 50 mm to 10 mm with
consumption of energy of 13 kw/(kg/s). What will be the consumption of energy needed to crush the same
material of the average size 75 mm to an average size 25
mm
?
a) Assuming Rittinger’s law b)
Assuming
Kick’s law.

9) Describe the principal, construction and working of Hammer mill.

10
) Discuss

Open circuit grinding & closed circuit grinding w.r. t. Following points:

a. Concept
of open

circuit grinding and closed circuit grinding

b.

Necessity
of open and closed circuit grinding

c.

10)

Describe the principal, construction and working of Hammer mill.

3. SIZE SEPARATION OF
SOLIDS

1)Define

capacity and effectiveness of screen.

2)Give difference between actual screen and ideal screen.

3)Describe with neat diagram construction and working of
Trammel
.

4)Write a note on screen analysis.

5)A mixture of 50mesh; 100 me
sh and 150 mesh size particles are to be separated. Give
trammel

arrangements for this with diagram.

6)Write note on ‘’std. Screen series’’.

7)What are the factor affecting the performance of screen.

8)Derive an expression to
calculate effectiveness of screen .

9)Describe working of
trammel
.

1)mesh number

10)Describe cumulative oversize analysis of a screening exptt. conducted in laboratory.

11)Define mesh and screen aperture.

12)Write the equation for

finding the overall effectivene
ss of screen.

13)Why cumulative analysis is more efficient than differential analysis.

14)A 100 mesh screen is used for size separation. The ratio of overflow to underflow is 0.75.
Analysis of
two fraction shows the overflow contain 89% over size material and underflow contain
27% oversize material. Calculate the overall effectiveness of the screen. Also calculate % of oversize
and % undersize in the feed.

15)Compare

ideal screen and actual screen. Draw graph to explain the same.

16)Write the overall material balance, material balance based on oversize and undersize particle for
screening operation.

17 )State the principle of screening .Gi
ve the name of four equipment used for screening.

18)Write down the expression for effectiveness of screen and explain term.

19) Define:

1) oversize and undersize particle in screening .

2)

Mass

number

20)Derive

the expression for effectiveness of screen.

21)E
xplain how screen analysis is done.

22)
With neat diagram explain the construction and working of grizzlies.

23) Define

oversize and undersize
i
n

screening .

24) W
hat
is
screen

effectivene
ss .

25)

Define Electro
-
osmosis.

26)
D
ifferentiate between actual screen and ideal screen on basis of efficiency and

fg
separation ef
fectiveness .

27)Draw diagram of trammel for separation of different size particles.

28)Describe various method of screen analysis.

Q .1) Write down expression for screen effectiveness of screen and explain the term involved.

Q.2) Explain di
fferential method of screen analysis with suitable example and necessary graph.

Q.3) Explain standard screen with suitable example .

Q.4 Define ideal screen

Q.5) What is mesh number ?

Q.6) Differentiate between ideal screen & actual screen on the basis of

efficiency & separation
effectiveness.

Q.7) A mixture of 50 mesh , 100 mesh & 150 mesh size particles are to be separated. Give trammel
arrangement for this with diagram.

Q.8) Draw two graphs to represent various methods of screen analysis.

Q.9) describe
Cumulative screen analysis method.

4. Methods of separation of solid based on specific properties

1) Give the principle of working of cyclone separator.

2) Explain the working of cyclone separator.

3) Explain the working of hydraulic
jig.

4) Which properties is used for separation of solid mixture in hydraulic jig.

5) What is promoter and collector.

6)

Explain Dorr classifier.

7) Describe with neat diagram construction and working of Dorr thickener.

8) Explain:

a) Mecha
nically agitated vessel for gas
-
liquid system.

b) Sigma.

9) Describe construction and working of cyclone separator with neat diagram.

10) Explain

Ball
-
Norton magnetic separator.

11) What is the forth flotation?

12) Draw neat diagram of m
agnetic head pulley and label the parts.

13) What is the used of cyclone separator? Explain working with neat diagram.

14) Draw neat diagram of a hydraulic jig and describe its working
.

15) State the principle of forth flotation operation.

16) What is the
role of promoter in forth flotation?

17) State the principle of jigging.

18) Explain the working of rake classifier.

19)

Give the principle of involved in electrostatic separation .List various method used for

Charging particle.

Explain the working of plate and pipe type electrostatic precipitator.

20) Which properties is used in separation of solid
-
mixture by forth flotation cell.

21)

Write down principle involved in

separation of solid mixtures by electrostatic

Precipitator.

22) Describe the principle involved in hydraulic jig.

23) Describe the any two mixers used for mixing.

24) Describe gas
-
solid
separation of cyclone.

25) Describe with neat diagram working of magnetic separator.

26) Describe construction and

working of any filtration equipment.

5.

Filtration

1) Define pressure filtration.

2)Give example of two filter acid used in filtration.

3)Why hot
slurries are not filtered in rotary drum vacuum filter.

4)Explain the factor which affects the rate of filtration.

5)Draw the diagram of washing and non washing type of plate and frame filter press

With flow diagram.

6
)
derive the equation for calculating time for constant pressure filtration.

7)Filter are neither operated under constant pressure nor under constant rate: Give

Reason.

8)Explain the working of pressure sand filter.

9)State the principle of filtration.

10)Draw a neat diagram of non washing type of plate and frame filter press.

11)describe four factors affecting the rate of filtr
ation.

12)

Draw a neat diagram of a top driven basket centrifuge.

13)Calculate the operating speed of a ball mill from the following data:

1)diameter of ball mill = 675mm

2) diameter of ball = 55mm

If

a)
operating speed is 75% less than critical speed.

b) operating speed is 50% less than critical speed.

14)Describe the following of a washing type of plate and frame filter press.

15) Define

a) constant rate filtration.

16)
Differentiate between pressure filter and vacuum filter with respect to upstream

And downstream side pressure.

17)Draw a neat diagram of vacuum drum filter and name its parts.

18)Explain the effect of following term on

rate of filtration:

1)Area of filtration.

2)Viscosity of filtrate.

19)Draw a neat diagram of basket centrifuge and name its part.

20)Draw neat diagram of continuous rotary filter.

21)Draw neat diagram

of plate and
frame filter press.

22)Sate the equation for constant rate and constant pressure filtration. Explain

term involved it.

23)Name tow filter media used in filtration.

24)Explain rotary vacuum filter.

25) Sate and Explain type of

filtration.

27)

Draw neat sketch of washing type plate and frame filter press.

6.

SEDIMENTATION

1) Define free settling.

2)State the function of thickener. Draw the

diagram of Dorr thickener, showing

The various zone in it.

3)

Give application of sedimentation in industry.

4)
Describe with diagram. Flow patterns in an agitated vessel. What is vortexing? How

Is it.

5) Describe batc
h sedimentation test.

6) Differentiate free setting and hindered settling by giving example of each type.

7) Name various zones in a laboratory setting test.

8) Draw a neat labelled diagram of gravity settling tank and write it’s working.

9)Descri
be construction of a batch thickner with diagram.

10) Draw a neat diagram of sequential steps taking place in a batch settling sedimentation

test (5 sketches).

11) Describe
the effect of change in concern of a slurry on the rate of

settling.

12) State and define type of settling.

13)Describe with neat diagram construction and working of dorr thickener.

14)Explain batch sedimentation experiment perform in laboratory.

15)State function of coagulates in sediment
ation.

16)
Describe method to avoid vortex formation during mixing.

17)What is sedimentation ? What is principle.

18)Define terminal settling velocity.

19)Explain the working of dorr thickener.

20)Draw the diagram representing batch

sedimentation test in lab.

21) Define:

(1) Free settling

(2) Hindered settling

Which type of settling take place in a concentrated slurry.

22.why coagulants are used in sedimentation ?

)

2)Differentiate free setting and hindered settling by giving example of each type.

7.

MIXING

1)Draw any two impellers used for mixing.

2)Explain the construction and working of sigma mixer.

3)Explain the working of ribbon blender.

4)Define mixing.

5)Describe any two mixer used for mixing.

6)Give method of prevention of swirling and vortex formation.

7)Explain n
ecessity of mixing.

8)What are type
of impellers used in mixing.

9)Give the application of sigma mixer.

10)Name the equipments used for solid
-
solid mixing. Describe any one of them.

11)Write the equation for finding out power consumption in a mixer. Explain the

term.

12)Explain the working of ribbon
blender.

13)What is function of baffles in an agitated vessel.

14)Define mixing and draw two type of imp
ellers used in a chemical industry.

15)Describe working of a sigma mixer with a neat diagram.

16)Describe two method of propeller mountings in an agitated vessel.