Crushers Jaw crusher Gyratory crusher Roll crusher Cone crusher Impact crusher 2. Ball mill and Rod mill 3. Screens Revolving screens Shaking screens Vibrating screens 4. Log crusher

1. Prepared by
Prof. Ashish Makwana
Civil Engineering Dept. - MEFGI
1Prof. Ashish Makwana

2. PRESENTATION
OUTLINE…
• Equipments used for the production of
aggregate
– Crushers
• Jaw crusher
• Gyratory crusher
• Roll crusher
• Cone crusher
• Impact crusher
– Ball mill and Rod mill
2Prof. Ashish Makwana

3. PRESENTATION
OUTLINE…
– Screens
• Revolving screens
• Shaking screens
• Vibrating screens
– Log Crusher
3Prof. Ashish Makwana

4. EQUIPMENTS USED FOR
PRODUCTION OF AGGREGETE
1. Crushers
a. Jaw crusher
b. Gyratory crusher
c. Roll crusher
d. Cone crusher
e. Impact crusher
2. Ball mill and Rod mill
3. Screens
a. Revolving screens
b. Shaking screens
c. Vibrating screens
4. Log crusher
Prof. Ashish Makwana 4

5. 1. Crushers:
• Crushers are used to break stones into different
sizes of aggregates.
• Based on the stage of crushing crushers are
three types:
– Primary crusher
– Secondary crusher
– Tertiary crusher
• Stones obtained from quarry are fed into the
primary crusher which reduces the size of
stones.
Prof. Ashish Makwana 5

6. 1. Crushers: (continued…)
• Stones obtained from primary crusher are fed
into secondary crusher where sizes of stone is
further reduced.
• Therefore, to obtain desired size of aggregate,
the stones are passed through 4 to 5 crushers.
𝐑𝐞𝐝𝐮𝐜𝐭𝐢𝐨𝐧 𝐫𝐚𝐭𝐢𝐨 =
size of stone fed into the crusher
size of stone obtained from crusher
Prof. Ashish Makwana 6

7. (a) Jaw Crushers:
• It has two jaws, one is stationary and other is
moving.
• The surface of both jaw is flat/convex.
• The space between two jaws is wider at top and
narrow at the bottom.
• The size of jaw is 1.68 x 2.14 m.
• The stones are crusher by the pressure of two
jaws.
• Large size boulders can also be crushed using
this crushers.
• Power consumption is minimum.
Prof. Ashish Makwana 7

8. Fig. Single jaw crusherProf. Ashish Makwana 8

9. Fig. Double jaw crusherProf. Ashish Makwana 9

10. Single toggle jaw
crusher
Double toggle jaw
crusher
(i) In a single toggle jaw
crusher whole swing jaw
is lifted, hence require
higher power.
(i) Require lesser power.
(ii) Jaw plates wear out at
faster rate.
(ii) Jaw plates wear out at
slower rate.
(iii) Lower initial cost. (iii) Higher initial cost.
(iv) Used for non-abrasive
and non hard rocks.
(iv) Economical for
abrasive and hard rocks.
Prof. Ashish Makwana 10

11. Size of jaw crushers:
• Mouth opening of the jaws denotes the crusher
size. Thus, a jaw crusher having a mouth
opening of 1200 x 1000 mm is called a 1200 x
100 mm crusher.
• The size of stone piece is restricted to 70 to 80
% of the gap size. Thus, for 1200 x 1000 mm
crusher the feed size should be restricted to 700
to 800 mm (70 to 80% of 1000 mm).
Prof. Ashish Makwana 11

12. Jaw setting and jaw opening:
• The jaw setting is measured at the bottom of the
jaw plates with jaws in open position on the
bottom side.
• The jaw opening at the top determines the size
of the rock.
• The crusher will receive (70 to 80% of the small
opening size).
• The capacity of the crusher is dependent on the
area of the opening at the bottom of the jaws.
Prof. Ashish Makwana 12

13. Fig. Crusher jaw setting and jaw opening
Prof. Ashish Makwana 13

14. Wear limits:
• With use, the teeth of the jaws are worm out.
• When teeth plats gets worn out to about 1/3 of
the original corrugation height the jaw plates
must be turned end-to-end.
• Wear limit dead line is when there remained no
corrugation.
• When the entire crushing surface gets worn out,
the teeth plate should be replaced with new one.
Prof. Ashish Makwana 14

15. Fig. Wear limit of tooth plate
Prof. Ashish Makwana 15

16. Tips for optimum use of jaw crushers:
• The feed size should be 70 to 80% of the
minimum opening size at top. Do not allow
biggest pieces going to the crusher mouth.
• Material fed should not be of same size. Mixed
feed of all sizes of material gives best results.
• For best results ratio of gap to jaw setting should
be 5:1 to 7:1. Gap is the longer distance
between the two jaws.
• The ratio of gap to width of jaws is 1:1.6 in
primary crushers and 1:4.5 in the secondary
crushers.
Prof. Ashish Makwana 16

17. (b) Gyratory crusher:
• A cone or head is fitted at the top for grinding.
• A bowl shaped head is known as mandrel.
• Stones are broken by the impact of the head.
• The frame of equipment is strong.
• Head is made of iron alloy
.
(c) Roll crusher:
• This equipment consists of heavy iron frame with
two hard iron rolls. Two rolls are fitted on
different horizontal shafts.
• They can be rotated by v-belt or flat pulley.
Prof. Ashish Makwana 17

18. (c) Roll crusher: (continued..)
• Stones are broken into small pieces between roll
and grinding plate.
• The equipment is light in weight and is suitable
for second grinding.
Feed size:
• The maximum size of material that can be fed to
a roll crusher is directly proportional to the
diameter of the rolls.
• If the feed contains stones that are too large, the
rolls will not grip the material and pull it through
the crusher.
Prof. Ashish Makwana 18

19. Feed size: (continued..)
The angle of grip, which is constant for smooth
rolls, has been found to be 16̊ 45’.
The maximum size particles that can be crushed
are determined as follows.
R = radius of rools
B = angle of grip (16̊ 45’)
D = R cos B = 0.9575 R
A = maximum feed size
C = roll setting (size of finished product)
X = R – D A = C + 2X
= R – 0.9575 R = C + 2 (0.0425 R)
= 0.0425 R = C + 0.085 RProf. Ashish Makwana 19

20. Capacity of roll crusher:
The capacity of roll crusher depends upon:
Type of stone Width of rolls
Size of feed Speed at which rolls rotate
Size of finished product Uniformity of feeding
Capacity of roll crusher:
Q = CWV x 3600 x η cum/hr.
Q = Capacity in cum/hr.
C = roll setting in metre
W = width of rolls in metre
V = surface speed of roll in m/sec.
η = efficiency
Prof. Ashish Makwana 20

21. Type of roll crusher:
i. Both roll shells smooth
ii. Double toothed roll crusher
iii. One smooth and on corrugated shell
iv. Corrugated rolls
v. Spiked roll crusher
Prof. Ashish Makwana 21

22. i. Both roll shells smooth:
• These are used when required size of finished
product is less than 12 mm.
• These are widely used in quarrying industries,
mining, ceramic and metallurgical industries.
• Out of the two rolls one roll is fixed and other is
floating.
• Each roll is individually driven by 3-phase electric
motor via v-belt.
• The gap can be adjusted to suit the size of the
material.
Prof. Ashish Makwana 22

23. ii. Double toothed roll crusher:
• These are generally used for the production of
material over 25 mm size and for reduction of
coarse soft and medium hard, non-abrasive
materials like coal, slag, ore, limestone etc.
• The principle of working is the same as that of
smooth roll crusher.
iii. One smooth and one corrugated shell:
• These are used for materials of medium hard
qualities.
• They are used for producing the material between
12 to 25 mm size.
Prof. Ashish Makwana 23

24. Fig. One smooth and one corrugated shell
Prof. Ashish Makwana 24

25. iv. Corrugated rolls:
• The size of corrugation (pitch and depth) is
related to the product size, and hence the smaller
the product, the finer is the corrugation.
• These can take bigger feed size than plain rolls of
the same diameter.
v. Spiked roll crusher:
• These can take large feed size, even a slab of 1.2
m x 1.5 m x0.3 m size.
• These have one spiked roll and one adjustable
jaw and are used for coarse crushing of material
like coal.
Prof. Ashish Makwana 25

26. (d) Cone crusher:
• Cone crusher are used for second or third
grinding.
• Uniform size aggregates are obtained.
• A head of manganese iron is fitted on the vertical
shaft, which act as grinding surface.
• The second surface is concave.
• The rotation of shaft produces gyratory effect
which causes grinding of stones.
Prof. Ashish Makwana 26

27. Fig. Cone Crusher
Prof. Ashish Makwana 27

28. Salient features of Gyratory and cone
crushers:
• As moving parts are small in number, wear, tear
and maintenance is less.
• Longer life
• Dust has little effect.
• Hydraulic system enables finger tip control of the
machine.
• Wear is uniform and adjustment is simple.
• Cleaning by hydraulic system enables rapid
restart after a blockage during operation.
• These have devices to measure oil pressure, oil
temperature and oil circulation. In case of
abnormal condition there may be sound or visual
alarm. Prof. Ashish Makwana 28

29. (e) Impact crusher:
• Impact crushers are used where materials are too
hard and abrasive and finished product requirement
is for cubical shape well graded material.
• In this type of crusher, stones are broken by means
of impact and not by compression as in jaw crusher.
• Stone is normally fed into the top of a breaking
chamber and struck by rotating hammers while it is
in suspension.
• The hammers repeatedly throw the material against
breaker bars (repulsion plates) forming the roof of
the breaker chamber.
• Hammers are fixed to the rotor.
Prof. Ashish Makwana 29

30. Advantages:
• High reduction ratio
• Effective production of a high percentage of
fines
• Excellent shape i.e. free from flake
• High output per unit energy
• Better mechanical strength
• Lower initial cost
• Have fewer parts to maintain
• Produce well graded cubical shaped product
Prof. Ashish Makwana 30

31. Fig. Impact CrusherProf. Ashish Makwana 31

32. Points to be kept in mind while selecting
crusher:
1. Type of rock 2. Size of rock pieces
3. Method of feeding rocks
in the crusher
4. Required capacity of the
plant
Prof. Ashish Makwana 32

33. Fig. Portable – aggregate processing plant flow dia.Prof. Ashish Makwana 33

34. Fig. Portable – aggregate processing plant flow dia.
Prof. Ashish Makwana 34

35. Crushing plant:
• Crushing plants with capacities upto 1000 tons
per hour are being manufactured by various
manufacturers all over the world.
• These plants are either stationary or portable.
Crushing plant
Primary crushing units
e.g. Jaw crusher Impact crusher
Reduces the rocks to sizes
Between 75 to 250 mm
Secondary crushing units
e.g. Jaw crusher Cone crusher
Impact crusher
Reduces the rocks to sizes
Between 5 to 50 mm
Prof. Ashish Makwana 35

36. Fig. Flow diagram of aggregate mixing plantProf. Ashish Makwana 36

37. 2. Ball mill and rod mill:
• A rod mill consists of an iron cylindrical shell with
hard mineral coating on the inner surface.
• A number of iron rods are kept inside the cylinder.
• The length of rods is kept slightly smaller than the
length of cylinder.
• Stone pieces are fed from inlet and sand size fine
aggregates are obtained at the other end.
• The mill can be operated in dry or wet condition.
• The size of mill can be expressed in terms of
diameter and length of the cylinder, e.g. 2.5 m x 3.5
m.
• If steel balls are charged in the cylinder instead of
iron rods, it is called ball mill.
Prof. Ashish Makwana 37

38. Fig. Section through a rod mill
Prof. Ashish Makwana 38

39. Fig. Section through a ball millProf. Ashish Makwana 39

40. 3. Screen:
• Screens are used to separate aggregates
according to different sizes.
• The size of aggregate is expressed as range,
e.g. passing 12 mm screen and retained on 6
mm screen.
Types of screen:
a. Revolving screens
b. Shaking screens
c. Vibrating screens
Prof. Ashish Makwana 40

41. a. Revolving screens
• They are more advantageous when they are
used to wash and screen sand and gravel.
• The operating action is slow and simple.
• Maintenance and repair costs are low.
• If the aggregate to be washed contains silt and
clay, a scrubber can be installed near the
entrance of a screen to agitate the material in
water.
• At the same time, streams of water can be
sprayed on the aggregate.
Prof. Ashish Makwana 41

42. b. Shaking
• In this type, the screen is kept inclined at 15̊ to
20̊ with horizontal.
• The screen is agitated in the direction of length
for a distance of about 15 cm at the rate of 100
strokes per minute.
• Fine material fall below the screen while coarse
material fall at the end of the screen.
Prof. Ashish Makwana 42

43. c. Vibrating screens:
• This type of screens are more frequently used
for screening of aggregate.
• They consists of one or more layers or ‘decks’ of
open mesh wire cloth mounted one above the
other in a rectangular metal box.
• The vibration is obtained by means of an
eccentric shaft, a counterweight shaft or
electromagnets attached to the frame or to the
screens.
• A unit may be horizontal or inclined with slight
slope (20̊ or less) from the receiving to the
discharge end.
• The vibration, 850 to 1250 stokes per minute
causes the aggregate to flow over the surface of
the screen. Prof. Ashish Makwana 43

44. 4. Log washer:
• When natural deposits of aggregate, such as
sand and gravel, or individual pieces of crushed
stone contain deleterious material, it will be
necessary to remove these materials before
using the aggregate.
• One method of removing the material is to pass
the aggregate through a machine called a “log
washer”.
• This unit consists of a steel tank with two electric
motor driven shafts, to which numerous
replaceable paddles are attached.
Prof. Ashish Makwana 44

45. 4. Log washer: (continued..)
• When the washer is erected in a plant, the
discharge end is raised.
• The aggregate to be processed is fed into the
unit at the lower end, while a constant supply of
water flows into the elevated end.
• As the shafts are rotated in opposite directions
the paddles move the aggregate toward the
upper end of the tank, while producing a
continuous scrubbing action between the
particles.
• The stream of water remove the undesirable
material and discharge it from the tank at the
lower end, whereas the processed aggregate
will be discharged at the upper end.
Prof. Ashish Makwana 45

46. Prof. Ashish Makwana 46