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 1 = -------- 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.

OBSERVATION TABLE:Sr. no. Mesh no. Aperture No.

Dp (mm)Mean dia Dp Feed size Product size

CALCULATION:

E2 = --------- = --------------KW E1 = --------- = --------------KW E2- E1 = --------------- KW PE = ------- = ----------- 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) Bond’s law:

PM

=Wi

√10 ( 1

√D sb

−1

√Dsa )= PM

=0.3162Wi( 1

√Dsb−

1

√D sa)

Example:Data given:Feed – 0.5 cm.Product - .03 cmFeed rate – 100 kg/hr.=0.1 t/hr. = 0.1/60 = .001 t/minWork index – 12.74. from reference book. Find out p – power required to grind sample.

=.0016*0.3162*12.74[ 1

√ .03− 1

√3.75 ]=0.00644(5.88-0.516)= 0.03 Kw