cryogenic grinding - WordPress.com

petnamelessΠολεοδομικά Έργα

15 Νοε 2013 (πριν από 3 χρόνια και 11 μήνες)

121 εμφανίσεις


CRYOGENIC GRINDING

1

2

OBJECTiVES


INTRODUCTION


PROBLEMS IN CONVENTIONAL GRINDING


WORKING


ADVANTAGES OF CRYO GRINDING


EXPERIMENTAL STUDIES


APPLICATION





CRYOGENICS

The

term



Cryogenics”

originated

from

the

Greek

word

which

means

creation

or

production

by

means

of

cold
.

Cryogenics

is

the

study

of

very

low

temperatures

or

the

production

of

the

same
..

Liquid

nitrogen

is

the

most

commonly

used

element

in

cryogenics

and

is

legally

purchasable

around

the

world
.



3

APPLICATIONS OF CRYOGENICS



In Gas Industry



As the source of gas



As Rocket propellant



In Biology



In Food Industry



In Electronics



In Medicines



In Grinding



4

GRINDING

The process is carried out with a grinding wheel made up of grits for
removing materials from work piece surface.

Grinding can be classified into two types

5




Grinding for material removal



Grinding for powdering


PROBLEMs IN CONVENTIONAL
GRINDING PROCESS


High heat generation


Introduction of tensile residual stress


Less tool life


Clogging and Gumming of the mill


Oxidation


Loss of Etheric oil in Spice grinding

6



Now….elimination of all these problems are required……..

But……….




HOW
..???

7

Here comes the
necessity

of

CRYOGENIC

GRINDING

…..
also known as

Freeze Grinding

8

Cryogenic grinding involves cooling a material below its
embrittlement temperature with cryogenic fluid. Typically
Liquid Nitrogen or in certain applications, liquid Carbon
Dioxide is used
.





CRYOGENIC
GRINDInG

9


This process has several benefits






Ability to process soft or elastic material



Increased productivity



Low Power Consumption



Smaller size particle





Minimal loss of volatile component


10

WORKING

11

06/09/2010

ADVANTAGES OF CRYOGRINDING



Increased throughput & power saving



Finer particle size



More uniform particle distribution



Lower grinding cost



No heat generation




Provides an inert atmosphere



Reduced grinding force



Provide clean and pollution free environment



Prevent oxidation



Possibility of fine grinding of difficult spices


12

































SL No.

Components

Cryoground
(%)

Conventional

ground
(%)

1

Moisture

13.00

11.00

2

Volatile oil


2.61

1.15

3

Flavour compounds

(relative concentration)

Alpha
pinene

limonene



1.40

8.30



0.29

1.18

RESULTS OF EXPERIMENTAL STUDIES

1. Volatile oil content & flavor component

Example : pepper

13

2. Throughput of the mill

Current required =6A

Working temperature =50
°
C

Throughput of conventional grinding =22kg/hr

Throughput of cryogenic grinding =50kg/hr

i.e. throughput for cryogenic grinding is 2.25 times more
than conventional grinding

14

APPLICATION OF CRYO
-
GRINDING



recycling of composite materials



Thermoplastics



Thermo sets



Adhesives & waxes




Explosives



Spices

15

Hence we can conclude …..

16

THank you …

17

QUESTIONS ? ?

18