CRYOGENIC

GRINDING

Presenting,

By;D YASHWANTH REDDY

IntroductionProblems faced in Conventional GrindingCryogenic Grinding TechnologyWorking Principle of CryoGrinderPerformance Data &Technical DataMerits & DemeritsField of applicationsConclusion

CONTENTS:

The term “CRYOGENICS” originates from Greek word which means creation {or} production by means of cold.

Cryogenics is the study of very low temperature {or} the production of the same, Liquid nitrogen is the most commonly used element in Cryogenics & is legally purchasable around the world.

Cryogenic Grinding technology can efficiently grind most tough materials & can also facilitate Cryogenic recycling of tough composite materials & multi component scrap.

The Cryogenic process also has a unique capability for recycling difficult to separate composite materials.

INTRODUCTION:

High heat generation. Introduction of tensile residual stress.Less tool life.Clogging and Gumming of the mill.Oxidation.Loss of Enteric oil in Spice grinding.

PROBLEMS FACED IN CONVENTIONAL GRINDING PROCESS:

HOW..???

Now….elimination of all these problems are

required……..But……….

Here comes the necessity of

CRYOGENIC GRINDING

…..also known as Freeze Grinding

CRYOGENIE GRINDING TECHNOLOGY:

For pulverizing many materials, Cryogenic Grinding Technology increases productivity & lower power cost.

Many elastic {or} “soft” materials are very difficult to pulverize(crush to fine particle),requiring long cycle times & high power/energy consumption.

Cryogenic grinding involves cooling a material below its embrittlement temperature with a cryogenic fluid, typically liquid nitrogen.

After cooling, the material is fed into an impact mill where it is reduced in size primarily by brittle fracture.

WORKING OF CRYO-GRINDER:

Schematic representation of Cryo-Grinder

Material is to be ground is cleaned manually & fed into the hopper.

From the exit of the hopper the material enters into the vibratory feeder, which is positioned with a small inclination towards the entry of the helical screw conveyor, It has ability to control the fed rate.

Liquid nitrogen from the storage container is sprayer into the screw conveyer, The time of stay of material in the conveyer can be maintained by varying the speed of the drive i.e., conveyer drive.

The sensors monitors material’s temperature in the conveyer.

When the mill is running, the material gets crushed between the studs & comes out through an optional sieve as a ground product.

To the bottom of the mill a collecting bin is housed where the ground product gets collected.

The vaporized nitrogen from the mill is sucked by a centrifugal blower & through the filter assembly is fed back to the mill, And the cyclic process is continued.

Schematic representation of CryoGrinder

Cryo-Grinding_mill_machine_operation_working_principle_.mp4

Performance Data Cryo-Mill

Field Of Application* Size reduction, Homogenation

Feed Material* Hard, Brittle, Soft, elastic & Fibrous

Feed size* Up to 8 mm

Final Fineness* Approx. 5micro-mm

Batch/Sample Volume* Max.20ml

Typical Mean Grinding Time* Pre-cooling:10 minsgrinding 1 minute

Memory for Parameter Combination* 1 nos

Technical Data Parameters

Power Consumption 160 Watts

W*H*D 385*370*570 mm

Net Weight Approx. 46 Kg

*depending on feed material & instrument configuration/setting.

MERITS: Increased throughput & power saving. Finer particle size. More uniform particle distribution. Lower grinding cost. No heat generation. Prevent oxidation.

DE-MERITS:High power consumption.High operation cost.Maintenance cost is above the range.Filtering of Screw Conveyer is Difficult.

MERITS & DE-MERITS:

CryoGrinding of Steel; The large amount of Heat is generated during machining/grinding at high

speed & feed rate raises the temperature at the cutting zones excessively.

To overcome this problem liquid Nitrogen is fed to the grinding spot. Thermoplastics & Thermo sets;

To which Nylon, PVC, Polyethylene, synthetic rubber are commonly used in powder form, but not limited to, a variety of applications such as adhesives, powdered coatings, fillers & plastic sintering & molding.

Adhesives & waxes; To avoid pliable & sticky of certain materials which is unable in

conventional grinding. Explosives;

To grind the explosive materials(TNT) below their Ignition Temperature. Spices;

To overcome the volatility of Etheric Oils (gives the taste & smell of spices).

FIELDS OF APPLICATION:

Hence We CAN CONCLUDE THAT....

THANK YOU

Presented by:

D YASHWANTH REDDYLINGADALLI PRAKASH