Crusher and Its Types

PARTICULATE TECHNOLOGY (PRACTICAL)
TRAINER: MIR MUHAMMAD BOZDAR
MAZHAR SHAFI 17-CH-10
CRUSHER:
A crusher is a multi dimensional machine which is designed to reduce large
size materials into smaller size materials. Crushers may be used to reduce the
size, or change the form of waste materials so they can be more easily disposed
of or recycled, or to reduce the size of a solid mix of raw materials (as in the
case of ore), so that pieces of different composition can be differentiated for
separation.
Crushers are normally low speed machines that are designed for breaking
large lumps of ores and stones, even aving a size with a diameter of over one
and half meter. The purpose of crusher is to reduce the size of the materials for
making them usable in construction or industrial use, or for extraction of
valuable minerals trapped within a ore matrix.
Crushing is the process of transferring a force amplified by mechanical
advantage through a material made of molecules that bond together more
strongly, and resist deformation more, than those in the material being
crushed do. Crushing devices hold material between two parallel or
tangent solid surfaces, and apply sufficient force to bring the surfaces together
to generate enough energy within the material being crushed so that its
molecules separate from (fracturing), or change alignment in relation to
(deformation), each other.
There are four basic ways to reduce material.
Impact
Attrition
Shear
Compression

IMPACT
In crushing terminology, impact refers to the sharp, instantaneous
collision of one moving object against another. Both objects may be
moving, or one object may be motionless. There are two variations of
impact, namely (i) gravity impact, and (ii) dynamic impact. Material
dropped onto a hard surface such as a steel plate is an example of
gravity impact. Gravity impact is most often used when it is necessary to
separate two materials which have relatively different friability. The
more friable material is broken, while the less friable material remains
unbroken. Separation can then be done by screening. Material dropping
in front of a moving hammer (both objects in motion), illustrates
dynamic impact. When crushed by gravity impact, the free-falling
material is momentarily stopped by the stationary object. But when
crushed by dynamic impact, the material is unsupported and the force
of impact accelerates movement of the reduced particles toward breaker
blocks and/or other hammers. Dynamic impact has definite advantages
for the reduction of many materials.
ATTRITION
It is a term applied to the reduction of materials by scrubbing it between
two hard surfaces. Hammer mills operate with close clearances between
the hammers and the screen bars and materials reduce by attrition
combined with shear and impact reduction. Though attrition consumes
more power and exacts heavier wear on hammers and screen bars, it is
practical method for crushing the less abrasive materials such as
limestone and coal.

SHEAR
It consists of a trimming or cleaving action rather than the rubbing
action associated with attrition. Shear is usually combined with other
methods. For example, single roll crushers employ shear together with
impact and compression. Shear crushing is normally called for under
the conditions when material is somewhat friable or when a relatively
coarse product is desired. It is usually employed for primary crushing
with a reduction ratio of 6 to 1.
COMPRESSION
As the name implies, crushing by compression is done between two
surfaces, with the work being done by one or both surfaces. Jaw
crushers using this method of compression are suitable for reducing
extremely hard and abrasive materials. However, some jaw crushers
employ attrition as well as compression and are not as suitable for
abrasive materials since the rubbing action accentuates the wear on
crushing surfaces. As a mechanical reduction method, compression is to
be used if the material is hard and tough, if the material is abrasive, if
the material is not sticky, and where the finished product is to be
relatively coarse.

TYPES OF CRUSHER
JAW CRUSHER:
One of the most commonly used crushing machine is the jaw crusher. It is a
heavy-duty machine that is generally used for crushing different kinds of raw
materials into smaller pieces. The jaw crushers can be seen in the mining and
disposal industry where large rocks need to be crushed into smaller pieces for
further use.
There are different jaw crushers on the market, but all of them are designed
and are consisted of fixed and moveable parts.
Fixed parts: the frame is the main fixed part of the jaw crasher. There are also
two mechanic build crafts: medium carbon steel and steel welding plate frame.
Moveable parts: jaw plate, eccentric shaft, bear, belt pulley and other
components.
The working principle of the jaw crushers is very simple. Powered by a diesel
or gas motor, the jaw crusher brakes materials in a crushing chamber. The
materials are pushed inside the chamber from the top opening and when
crushed they are released through the bottom opening. The crushing power of
the jaw crushers depends on the size of the chamber. The bigger the chamber,
the more powerful the jaw crusher. The crushing process can be basically
explained as a process where the materials are sandwiched between two jaw
plates. The movable jaw plates squeeze and crush the materials into several
small pieces.
There are two main types of jaw crushers: double toggle and overhead
eccentric jaw crusher. The only difference between these two crushers is the
location of the pivot joint. In the overhead eccentric jaw crushers, the pivot
joint is located at the bottom of the chamber, while at the double toggle

crushers, the pivot joint is on the top. The double toggle jaw
crushers are more preferred, simply because these crushers are described as
fuel-efficient and easy to operate machines.
The main technical features of the jaw crushers are:
Simple structure and convenient maintenance;
Stable performance and low operation cost;
Even particle and large crushing ration.

The jaw crushers can be used for crushing all kinds of hard
materials quickly and efficiently. Powerful and highly efficient, the jaw
crushers are essential pieces of equipment in the construction and mining
industry. They can be used in combination with other crushing machines for
more efficient performance. In most cases, the jaw crushers are used as
primary crushing machines in projects where high quality materials are not
needed.
GYRATORY CRUSHER
The gyratory crusher comprises a lined inverted conical crushing chamber
within which 'gyrate' an upright conical crushing member, the shaft and cone,
protected by a liner called the 'mantle'. The shaft does not rotate but 'gyrates' or
'processes' compressing material as it moves towards the wall of the chamber
and at the same time releasing material at the diametrically opposite point so
that crushed rock can descend through the chamber towards the discharge.
The frequency of this action is between 100 and 200 cycles per minute and
the movement or throws between 20 and 50mm. The crushers are usually
designated by the width of the feed opening and the diameter of the head. The
'gyratory' action can be created in several ways including: (i) a vertical shaft
running in upper and lower eccentric bushings supported by thrust bearings
or hydraulic means and (ii) the most common, a shaft located by an upper
fixed bearing within the spider and supported hydraulically, actuated by an
eccentric bushing at the lower point.
The principal advantage of the gyratory crusher is the much greater unit
capacity for any given 'gape' or maximum lump size assuming that this
capacity can be fully utilized to justify the substantially greater capital cost.
The reduction ratio is 4:1 to 6: 1 and the machine is suitable for all hard,

abrasive rocks but not for soft, porous material that may compact in the
chamber.
Gyratory crushers are sometimes employed at the secondary stage, where cone
crushers might be more usual, owing to their ability to accept larger lump
sizes

CONE CRUSHER:
Cone crusher and gyratory crusher work on the same principle. Both have the
same operation. If cone crusher differs then it is only from crushing chamber.
Cone crusher has a less steep crushing chamber and more parallel zone
between crushing zones.
Cone crusher parts
It breaks the rocks by squeezing it between the gyrating spindles. These
spindles are fully covered with resistant mantle and a manganese bowl liner
covers the hopper. Rocks get squeezed at the same moment when it enters in
between the bowl liner and mantle. Only one time breaking is carryout of
larger pieces of rocks from ore.
Broken pieces of rocks fall down to the next position where it is broken again.
Same process continues until the broken pieces become small enough so that it
can pass through the narrow opening that is at the bottom of the cone crusher.

ROLL CRUSHER:
The roller crusher is suitable for metallurgy, building materials,
refractory materials and other industrial sectors broken, higher
hardness of the material. The series of roll crusher is mainly
composed of the roller, the roller support bearings, compaction and
adjusting device and driving unit and other parts. The adjustment of
the discharging granularity: with a wedge or gasket between the two
roller adjusting devices, adjusting bolt, wedge at the top of the device
when the adjusting bolt will wedge pulled up, wedge rolling activity
to the top from the fixed wheel. The roll crusher will be broken
material feeding the mouth fall between two rollers, extrusion, and
finished product material nature. When the weather is good or not
broken, the roll crusher roller but by hydraulic cylinder or the role of
the spring automatic, make the roll gap. Increases, quality or broken
down, so as to protect the machine from being damaged. Relative
rotation of the two roll gap to a certain extent, change the gap, can
maximum discharging granularity control products. Double roll
crusher is the use of a pair of opposite rotating round roll; four roll
crusher is to use two opposite rotating round roll crushing
operations. The roll crusher (to roll crusher) applies to the cement,
chemical, electric power, mining, metallurgy, building materials,
refractory materials, coal and other industries of thick, brittle block
material intermediate crushing, it into the grain-size, discharging
granularity is adjustable, can fight pressure strength of 160 mpa or
less materials are broken. Especially in the coal industry, the use of
native raw coal fragmentation, as long as after iron, removing
impurity, without gangue removal, can be directly to broken, broken

out of material, granularity and the crushing rate is low, thereby
simplifying the coal preparation process, reduce the investment and
production cost.

IMPACT CRUSHER:
The word impact makes sense that in this particular type of crusher some
impaction is being used for crushing of rocks. In normal types of crusher
pressure is generated for the crushing of rocks. But, impact crushers involve
an impact method.
There is a hopper one side that takes the crushing material into the machine.
All material is carried only within a cage. This cage has an opening on the end,
bottom and on the side. These openings help in escaping the pulverized
material from the impact crusher. Normally such type of crusher is used for
crushing of materials that are not very hard say “soft material” and materials
that are non-abrasive. For example limestone, coal, gypsum, seeds etc.
Impact crusher description
ADVANTAGES OF IMPACT CRUSHER
1. Impact crusher has a blow bar that has very high chrome.
2. Impact crusher makes a very simple flow chart of crushing material.
3. Impact crusher has an ability to crush hard rocks.
4. It has high efficiency.

Hammer crusher
Hammer crusher consists of a high-speed, usually horizontally shaft rotor
turning inside a cylindrical casing. The crusher contains a certain amount
of hammers that are pinned to the rotor disk and the hammers are
swinging to the edges because of centrifugal force. Feed is dropped to the
crusher from the top of the casing and it is crushed between the casing and
the hammers. After crushing the material falls through from the opening in
the bottom.

IMPORTANCE OF WATER TREATMENT
IN INDUSTRIES:
Water treatment is an important industry requirement and comes under 4
main branches which include boiler water treatment, cooling water treatment,
water purification and the treatment of wastewater effluent. It is considered
that these cover the majority of Water treatment processes in the UK and
Internationally. Water treatment is often seen as an additional cost on top of
an already very expensive industrial processes and a bit of a business luxury if
the price is right. However water treatment can be hugely beneficial to your
business not least because it can save you tens of thousands of pounds per year
in operating costs but because of reduced maintenance it can also increase
efficiency and output. It is an industry which can quickly pay for itself and
give back in spades. As well as the financial benefits it is also important to
remember with use comes wear which is why it is hugely important with vast
operating plants to have your machinery operating efficiently and safely as not
only is your operation at risk but the safety and well-being of your employees
is too, efficiency and safety come hand in hand.
Boiler water treatment is a popular treatment process in industrial plants
because of the problem caused by scale formation and corrosion within the
system which comes with stream. This at best can cause increased energy costs
and a much decreased level of efficiency and a shorter plant life. At worst this
can lead to a catastrophic failure with the damage of machinery and more
seriously injury and loss of life. Boilers have to work with incredible pressures
as water heated in to steam expands in volume over 1000 times and has to

travel down narrow steam pipes at over 100 kilometres an hour.
Water treatment is an important aspect in making sure this process is kept safe
and efficient.
As with Boiler Water, Cooling Water processes also suffer from scale
formation and corrosion but also can be subject to fouling as they easily
become breeding grounds for harmful bacteria such as Legionella. This form
of pneumonia is the cause of Legionnaires Disease which comes with the
inhaling of water droplets which in most cases proves fatal. In addition to this,
untreated cooling water will more than likely reduce the efficiency of and
shorten your plant’s life, this can lead to unreliable and unsafe plant operation.
Left untreated you could be wasting £10,000s in energy, chemicals and water
charges every year. Specialised water treatment chemicals can prevent the
build-up of scale and corrosion thus preventing and reversing the effects on
industrial processes.
Chlorine Dioxide has these days become the favourite method of water
purification in industrial and commercial processes; this is because of a
number of the advanced and unique disinfection properties it carries. These
include its powerful, yet selective nature unlike Chlorine and Bromine ClO2 is
unaffected by changes in pH and is incredibly effective against biofilms. It can
readily permeate and penetrate biofilms that are normally resistant to most
disinfectants and chlorine. Legionella as stated before is a serious danger
should your water remain untreated and Chlorine Dioxide has been seen to be
extremely effective in the control and disinfection of the Legionella bacteria.
As you can see Water Treatment is a wide ranging industry and there is a need
for it in most industrial and many commercial sites, cost and safety are
inexplicably linked and in most theatres cost increases with investment in
safety but not with water treatment.

IMPORTANCE OF PARTICLE SIZE IN
INDUSTRIES:
The chemical, pharmaceutical, food and mining industries all rely on size
reduction. Its uses include grinding polymers for recycling, improving
extraction of a valuable constituent from ores, facilitating separation of grain
components, boosting the biological availability of medications, and producing
particles of an appropriate size for a given use. There are many types of size-
reduction equipment, which are often developed empirically to handle specific
materials and then are applied in other situations.
Knowing the properties of the material to be processed is essential. Probably
the most important characteristic governing size reduction is hardness because
almost all size-reduction techniques involve somehow creating new surface
area, and this requires adding energy proportional to the bonds holding the
feed particles together. A common way of expressing hardness is the Mohs
scale, on which talcum is a 1 and diamond is a 10. Also important is whether a
material is tough or brittle, with brittle materials being easier to fracture.
Other characteristics include particle-size distribution, bulk density,
abrasiveness, moisture content, toxicity, explosiveness and temperature
sensitivity. Flow properties can be major factors, too, because many size-
reduction processes are continuous, but often have choke points at which
bridging and flow interruption can occur. For instance, most size-reduction
equipment is fed by chutes, which might constrict flow. Often, the feed flows
adequately, but the crushed product will compact and flow with difficulty.
Intermediate storage bins might aggravate flow issues by causing compaction
andbridging.

For a given feed material, it is important to determine the desired particle-size
distribution of the product. In mining, for example, very fine particles can
interfere with separation processes, such as froth flotation, and might result in
loss of valuable components. In other operations, the objective might be to
produce very fine particles. Sometimes, as in sugar grinding, very fine particles
are agglomerated to increase the share of larger particles.
Many particle-size distributions can be represented by the Gaudin-
Schuhmann equation:
y = 100 (x/xm)Âª where y is the cumulative percentage of material that is
finer than size x, xm is the theoretical maximum size, and Âª is the distribution
modulus, which is related to hardness and has lower values for softer
materials (0.9 for quartz and 0.3 for gypsum, for instance). The equation
indicates that softer materials produce more fines
Nearly all size-reduction techniques result in some degree of fines. So unless
producing very fine particles is the objective, it usually is more efficient to
perform size reduction in stages, with removal of the desired product after
each operation.
Hardware options
Size-reducing equipment relies on compression or impact. Compression is
applied via moving jaws, rolls or a gyratory cone. The maximum discharge
size is set by the clearance, which is adjustable. Impact-based equipment
commonly uses hammers or media. The pros and cons of several types of size-
reduction equipment are shown in the table.
Rolls, in particular, can produce very fine particles. Rolls are used in flour
milling, where crushing yields different-sized particles, allowing separation of
purified flours. Moisture content is important so that, for example, the bran is
soft and remains in large pieces, whereas the endosperm is brittle and

fractures into small granules. Corn germ can be separated from
starch and fiber by roller milling because the germ selectively absorbs water
and is made
into flakes, whereas the starch fractures.
Impact mills use revolving hammers to strike incoming particles and to break
or fling them against the machine case (Figure 1). The hammers might be fixed
or, more commonly, pivoted. Typically, the hammers can be reversed to
provide added life before they need to be replaced.

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