Scribd
Upload
2K views4 pages

Hammer Mill

This document provides instructions for setting up and operating a hammer mill. It describes the main components of the hammer mill including the cylindrical casing that houses high-speed rotating hammers. Material is broken initially by hammer impact and further reduced by the hammers and liner plate through shearing and impact forces. Particle size of the product can be adjusted by changing screens. The document outlines procedures for an experiment to determine the power required to grind a 5kg feed sample using the hammer mill. Key steps include measuring feed size, grinding time, energy meter revolutions with and without load, and analyzing the product size distribution. Calculations are provided to determine the power required and grinding efficiency based on measured values and Bond's law.

Uploaded by

instrutech
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as DOCX, PDF, TXT or read online on Scribd
2K views4 pages

Hammer Mill

This document provides instructions for setting up and operating a hammer mill. It describes the main components of the hammer mill including the cylindrical casing that houses high-speed rotating hammers. Material is broken initially by hammer impact and further reduced by the hammers and liner plate through shearing and impact forces. Particle size of the product can be adjusted by changing screens. The document outlines procedures for an experiment to determine the power required to grind a 5kg feed sample using the hammer mill. Key steps include measuring feed size, grinding time, energy meter revolutions with and without load, and analyzing the product size distribution. Calculations are provided to determine the power required and grinding efficiency based on measured values and Bond's law.

Uploaded by

instrutech
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as DOCX, PDF, TXT or read online on Scribd
You are on page 1/ 4

INSTRUCTION MANUAL.

HAMMER MILL
SET UP
DESCRIPTION
SPECIFICATIONS
INSTALLATION REQUIREMENTS
INSTALLATION AND CONNECTIONS
PRECAUTIONS
TROUBLE SHOOTING

EXPREMENTATION
THEORY
OPERATING PROCEDURE
SYSTEM CONSTANTS
OBSERVATION TABLE
CALCULATIONS

AIM: To study the hammer mill


THEORY:

It consists of cylindrical casing which contain the high speed rotary


HAMMERS. A set of SIX hammers are FITTED to the disks. When feed is
introduced, they are initially broken by impact of hammer.

They then

strike against the liner plate where further size reduction is carried out.
These broken particles are further reduced by speed of hammer mill
hammers. These broken particles are further crushed by shearing action.
No grinding takes place on the surface of the screen. Screen is meant for
screening out of the particle which is fine.

The size of the product

obtained can be changed by changing the screen. The screen contains a


support plate so that the screen can be removing and thus particle size
can be changed
. The product obtained from this mill is up to 200 meshes.
PRINCIPLE:
It works on the principle of impact and shear.
PROCEDURE:
1. Note down feed size by screening.
2. Note down weight of feed. (5 kg.)
3. Switch of Hammer mill an note down time required for one
revolution of energy meter under no load condition.
4. Feed sample to hammer mill and calculate time taken for crushing
as well as time taken by energy meter for one revolution as well as
for crushing total sample i.e. feed.
5. Tabulate date and calculate power required at no load and load
condition.
6. Take a screen analysis of product and calculate crushing
OBSERVATION:
a) Initial size of feed L

= -------- cm. (80% feed pass through screen

of size x)
b) Energy meter constant ( w) = --------- Rev / KwH
c) Time for one revolution of energy meter under no load condition f1
= ----sec.
Power for no load condition E1= f1
X w -------------KW
d) Time for grinding (To) = -------- sec.

e) Time for one revolution under load condition of energy meter f2= --sec.
f) Power for load condition E 2 =

f2 X w ---------kw

g) Power required for GRINDING E 2 E1 = --------- kw


h) Feed rate (T) / 3600 = ----------- Tonn / Min.
i) H.P. required P = --------- H.P.(1 hp = 750 w or .750 kw)
P
j) E = T = ----------- H.P. ton /hr.

Sr.
no.

OBSERVATION TABLE:
Mesh no.
Aperture No.
Dp (mm)

Mean
Dp

dia

Feed size

Product
size

CALCULATION:
E2 = --------- = --------------KW
E1 = --------- = --------------KW
E2- E1 = --------------- KW
P
E = ------- = ----------- HP tonne/hr
T
Initial particle size Dpb = --------- = cm (80% product passes through
screen size)
Final particle size Dpa =----------cm (80% product passes through screen
size)
Bonds law:

P Wi
=
M 10
=

1
1

Dsb D sa

P
=0.3162 Wi
M

Example:
Data given:

1
1

Dsb Dsa

Feed 0.5 cm.


Product - .03 cm
Feed rate 100 kg/hr.=0.1 t/hr. = 0.1/60 = .001 t/min
Work index 12.74. from reference book.
Find out p power required to grind sample.

=.0016*0.3162*12.74
=0.00644(5.88-0.516)
= 0.03 Kw

1
1

.03 3.75

You might also like