Pin Mills are the mills used for grinding variety of things. The working, advantages, disadvantages, specifications and applications of Pin Mills have been well described in the presentation.

1. PIN MILLS
BY:- PRATHAMESH KUDALKAR 13FET1011
MONTICA SAWANT 13FET1007

2. A PIN MILL

3. SIZE REDUCTION
 Raw materials often occur in sizes that are too large to be
used and, therefore, they must be reduced in size.
 Size reduction of solids is termed as grinding or cutting.
Grinding usually refers to reducing solids to fine particles
while cutting involves reducing solids to macroscopic
particles.
 Grinding involves reducing the size of solid materials by
mechanical action, dividing them into smaller particles.
 It is an energy intensive process, therefore the selection
of right grinder is important.

4. TYPES OF MILLS
 The different types of mills used in fine grinding are as
follows:
 The Hammer Mill
 High Impact Turbo Mill
 Pin Mill
 The Vibrating Mill
 Stirred Media Mill
 Fluid Energy Mill
 Here after, we will concentrate on Pin Mills.

5. PIN MILL
 Pin Mills are type of Disc Grinders.
 Also known as Centrifugal Impact Mills (CIM)
 Pin mills are a type of high-speed-impact mills consisting
of a feed inlet, a set of two disks with concentric rings of
pins and a product outlet.
 Particle size of as low as 2 µm can be achieved with the
use of finest quality Pin Mills.
 Pin mills are capable of very fine grinding without the
need for screens and provide a uniform product size.

6. PRINCIPLE Pin mill employs shearing and impact forces to produce fine
particles
 The grinding action within the Pin Mill is achieved by
impacting the product particles with a series of hardened steel
pins.
 The product enters through the eye of the machine and then
passes through rows of pins rotating at high speed between
stationary pins.
 The product particles are shattered into fragments as they
progress towards the outlet, progressive becoming smaller in
size as they approach the periphery(this is because the
distance between the pins decreases as we move radially
outwards)
 The machine’s grinding action can be controlled by altering the

7. WORKING
 Pin Mill consists of two round disks parallel to each other.
 Material is fed continuously in the gap between the rotating disks.
 Depending on the type of the machine, one or both disks can rotate.
In cases where both disks rotate, the second disk rotates in counter
direction.
 Feeding of the product is usually done by means of a chute, shifting
the product in the hole center of one of the two disks.
 To reduce the temperature increase, air is blasted during grinding or
in construction to avoid oxidation, cooled inert gas is used; Blast of
inert gas helps prevent accumulation of particles in between the pins
and on the disks

8. WORKING
•The disk has several metallic pins, placed symmetrically
and concentrically on the disk surfaces.

9. WORKING
 The centrifugal force causes the particles to accelerate
outward toward the disc edges and pass through the pins
on the discs.
 The exiting particles impact a stationary outer ring (called
an impact wall or liner) typically consisting of stator pins
or a smooth or corrugated wall, which further reduces the
particles.
 Sieve of the required particle size is placed on the lower
part of the mill. It acts as a barrier mechanism to ensure
no particle having size more than specified is found in
the output.
 Thus, ground particles are obtained as output.

10. TYPES OF PIN MILLS
Vertical Pin Mill Configuration Horizontal Pin Mill Configuration

11. SPECIFICATIONS
 When one disc rotates , the size of the
ground particles is 50-5 micro meter . If
both the discs counter rotate , the particle
size may be reduced to 2 micro meter.
 Pin mills may grind 0.05-6 tons/hr.
 Depending on the product end size of
particles and capacity , the energy
consumption may vary from 3 to more than
100 kW.
 The specific energy consumption is10-
100kWh/ton at peripheral velocities 100-
200m/s
 Usually the peripheral velocity of the pin
grinder is 80-160m/s
 The diameter of the disc is upto 1m.
 The fineness of final product depends on
distribution of pins, the circumferential
speed of the rotors, the feed rate, and the
physical properties of the material.
Tips for specifying a Pin Mill
 Specify right number and
arrangement of pins
 Appropriate pin arrangement (typically in
rows) for your pin mill discs helps produce
the final particle size distribution of choice
and controls narrowness of that
distribution to meet your product
requirements
 Specify high quality parts
 Any internal mill surface in contact with
the material during grinding is subject to
wear, and in a pin mill this includes the
pins, the wear plate (that is, the disc
surface on which the pins are mounted),
the rotor, and the impact wall at the disc
periphery. These parts can also be
subject to corrosion if your pin mill
handles a corrosive material.
 Order wear parts to keep on
hand

12. ADVANTAGES AND DISADVANTAGES
ADVANTAGES DISADVANTAGES
•Very fine grinding at relatively
reasonable energy consumption
•Little floor space required
•Low maintenance
•Gravity or pneumatic feed
•Dry or wet grinding
•Easy cleaning ensures higher
hygiene standards
•Noiseless operation
•Various internal components are
available to custom-design the Pin
Mill to the process
•Low Capacity
•High wear
•Narrow range of size
reduction
•Internal cooling may be
required(heat damages
products like cocoa)

13. APPLICATIONS
Spices Foodstuff Biotech & Pharma Chemical
Germ Salt Spaghetti Pill Ore Iron oxide
Curry Rice Red bean Collagen Rosin Talcum powder
Clove Oats Black bean Chitosan Sulfur Washing powder
Garlic MSG Green bean Medicine Shellac Chemical materials
Fagara Sugar Pearl barley Agar ager Ceramic Calcium carbonate
Crocus Xylitol Banana chip Monascus Dyestuff
Mustard Barley Healthy food Antibiotics Pigment
Starch Dry vegetable Yeast powder Gypsum
Wheat Glutinous rice Chinese herbs Feldspar
Soybean Polysaccharide Pesticides

14. REFERENCES
 Handbook of Food Preservation, Second Edition- Edited
by Shafiur Rahman
 Handbook of Food Processing Equipment, Gustavo V.
Barbosa-Canovas, Washington State University
 Unit Operations in Food Processing : By R.L.Earle &
M.D.Earle
 Dry processing technology - A Review, Mineral Industry
Research Organisation, Warren Spring Laboratory
 Brochures of miscellaneous Pin mill manufacturers.

15. THANK YOU!