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Feed ManufacturingFeed Manufacturing

Process Flow Diagram

Receiving

Grinding

Mixing

Processing

Premixing

Liquid receiving& Storage

Packaging

Ware House

Bulk Loadout

FEED MANUFACTURINGFEED MANUFACTURING

Screening Particle Size Computerize Batching Mixing & Mixibility Mash & Pellet

GrindingGrinding

Why Do We GrindWhy Do We Grind Expose greater surface area for digestion. Improve mixing characteristics of ingredients. Improve the potential for further processing. Satisfying customer preferences

GRINDINGDEFINITION:

The particle size reduction which increases both

The number of particles The amount of surface area

per unit of volume

Also modify the physical characteristics of ingredients

Access to nutritional comp. as starch & Protein

Grain Interior is exposed to

digestive enzymes

Enhanced breakdown improves absorption in the digestive tract.

ANIMAL PERFORMANCE

Mixing Conditioning Pellet Quality Pelleting efficiency Feed handling & transport.

GRINDINGMATERIALS

Majority of materials either Within the feed plant or Prior to receiving.

Most Common are Grains

Corn Sorghum Wheat

Meals Canola meal Soybean meal

GRINDING PARTICLE SIZE

In past, Terms used were Fine Medium Coarse

Thus Standard procedure

1) Series of sieves are used2) Grain Amount Retained on

Each sieve analyzed3) Mathematical calculation /

Formula is applied

Particle size uniformity in a particular sample

These are relative terms Little use in evaluating

research on the particle size

GMD (Geometric Mean Diameter) Measured in Microns “μ”

GSD(Geometric Standard Deviation)

GSD uniformity GSD uniformity

PARTICLE SIZE Particle size of ground material by hammer mill

Using different screens

S. #Screen Size GMD

CategoryInches mm μ (range)

1 1/8 3.18 540—630 Finer2 3/16 4.76 680—720 Fine3 1/4 6.35 720—880 Medium4 ? 7.94 About 970 Coarse 5 ? 9.59 About 1200 Coarser

PARTICLE SIZE EFFECT ON PELLET DURABILITY

The accepted principles

1. A finer grind results in a more durable pellet.

2. Fine or medium ground materials

Surface area for moisture absorption from steam

better lubrication and increased production rates.

3. Very coarse grinds or large particle size

provide natural breaking points in pellets

Creating more fines, lowering pellet quality.

PARTICLE SIZE EFFECT ON NUTRIENT COMPOSITION

CORN Different fractions based on Particle Size

have little or no effect on nutrient composition. [ Nir et al. 1994 ]

CONCLUSIONS In pelleted or crumbled diets

little effect on live performance, uniformity of nutrient content of feedOr the pellet quality produced

If grains are to be incorporated into mash,Finer particle sizes (less than 600 µ GMD) should be

avoided. Producers should adjust grinding size depending the form of diet to

be fed ( Mash / Pellet) using hammer mill and roller mill grinding.

GRINDING METHODS FOR PARTICLE SIZE REDUCTION

HAMMER MILL OPERATION ROLLER MILL OPERATION

Principle General design Components design & specificationFunctional Advantages & Disadvantages

Hammer MillHammer Mill Most common grinding device Versatile and efficient Half circle, full circle, tear top, fixed hammer,

free to swing, fixed impact bars.

Hammer Mill

HAMMER MILL OPERATION GENERAL DESIGN

1) A delivery device (For material introduction)

2) Rotor Assembly With series of disks Mounted on the horizontal shaft

3) Free-swinging hammers Suspended from rods

4) Perforated screen 5) Removal of ground product

Either gravity- or Air-assisted

Horizontal shaft

HAMMER MILL OPERATIONHammers

Rotor Plates

Rod

Rotor Shaft

Rotor Assembly

Outlet & Take Away

Air Assist

Motor

Screen

Inlet

HAMMER MILL INTERIOR

The Grinding Theory

Hammers

Rod

Rotor Shaft

Outlet

Motor & Belt

Screen

Grinding Zone

HAMMER MILL FUNCTIONING

Inlet

System Design Factors

Feed material characteristics Size (decide multistep grinding or single) Moisture contents (determine dust collector) Grindability (hardness, density etc..) Temperature sensitivity Hammer mill factors Operating requirements (capacity, horsepower,

hammer-tip speed) Safety requirements (magnets, exploisable, sensors )

Contamination and Cleaning Requirements Space Requirements Maintenance Requirements Related equipments Feeders Drives Sensor Monitoring

System Design Factors

HAMMER MILL OPERATION VARIABLES

a) # Of Hammers on shaft b) Size of Hammers used c) Arrangement manipulated d) The hammer Sharpnesse) Hammer Wear patternsf) Hammer-tip speedg) Screen design h) Screen hole sizei) Whether or not air assist is used.

GRINDING CAPACITY

APPEARANCE OF THE PRODUCT

4.06

2.84

1.63

0.85

0

1

2

3

4

5

Prod. Rate T/H

900 700 500 300

Partile size (Mirons)

Particle size & Rate of Production

HAMMER MILL OPERATION COMPONENTS DESIGN & SPECIFICATION1. DELIVERY DEVICE / FEEDERS

Screw feeders, Rotary vane pocket feeders, Vibratory feeders, Belt feeders, Drag feeders, "Pocket" feeder, Fitted with a Rotor

Considerations For Feeder Selection

Initial cost, Evenness of feed, Compatibility with product Physical size of the feeder, The estimated maintenance cost

Screw Feeder

Rotary vane pocket feeders

COMPONENTS DESIGN & SPEC.2. HAMMER DESIGN

Optimal hammer design Maximum contact with the feed ingredient.

SIZE: Rotor speed = 1,800 rpm, 10 In. Long, 2.5 In. Across & 0.25 In Thick Rotor speed = 3,600 rpm, 6 to 8 In Long, 2 In Across, & 0.25 In Thick

NUMBER: For 1,800 rpm = 1 for every 2.5 to 3.5 HorsepowerFor 3,600 rpm = 1 for every 1 to 2 Horsepower

DISTANCE:The distance b/w hammer & screen = 0.5 In For cereal grains.

HAMMER TIP SPEED:Tip speed of the hammers is critical for proper size reduction Tip speeds commonly Range Between 16,000b & 23,000 F/ M

COMPONENTS DESIGN & SPEC.3. SCREEN DESIGN:

Open area of screen Determines The particle size & Grinding efficiency.

DESIGNDesigned to maintain The Integrity & Greatest amount of open areaGenerally Screen openings (holes) aligned in a 60-dig. Staggered pattern

This method will result in a 40 percent open area Optimized open area while maintaining screen strength

OPEN SCREEN AREA TO HORSEPOWER.

Recommended ratio for grains = 8 to 9 square Inch per Horsepower. Not enough open Area / Horsepower generation of heat. Generated Heat Exceeds 120F to 125F (44C to 46C)

Capacity may be decreased as much as 50 percent.

COMPONENTS DESIGN & SPEC.4. GROUND MATERIAL REMOVAL

A critical design feature Directly affects the efficiency of operation

Also affects the particle size determination

AIR ASSIST SYSTEM Most newer hammermills are equipped

Draws air into the hammermill with the product to be ground. Provide Reduced pressure on exit side of the screen Disrupt the fluidized bed of material on the face of the screen

Allow particles to exit easily through screen holes.

HAMMER MILL OPERATION ADVANTAGES

Ability to grind wide variety of materials.

Produce a wide range of particle sizes

Work with any friable material and fiber

Less initial purchase cost compared to roller mills

Minimal maintenance expense

Uncomplicated Operation

DISADVANTAGES

May generate heat (source of energy loss)

Create noise pollution Create dust pollution Produce greater particle

size variability (less uniform)

ROLLER MILL OPERATION PRINCIPLE

SIZE REDUCTION Combination of Forces and Design Features. Rolls rotate at same speed,

Compression is the primary force used. Rolls rotate at different speeds,

Shearing + compression are the forces used Rolls are grooved,

Tearing & Grinding components introduced.Coarse grooves Less size reduction Finer grooves More size reduction

ROLLER MILL OPERATION GENERAL DESIGN

1) A Delivery Device To supply a constant and uniform amount of the material

2) Pair Of Rolls Mounted horizontally in rigid frame

3) One roll Fixed in position And Other is Moveable closer to or further from fixed roll

4) Rolls counter rotate either at same speed or one may faster

5) Roll surface may be smooth or have various grooves

6) Pairs of rolls may be placed on top of one another in a frame.

Rotor

1st Roll Pair Coarse Grooves

Coarse ground Material

Inlet Bin

2nd Roll Pair Fine Grooves

Fine Ground Material

ROLLER MILL OPERATION COMPONENTS DESIGN & SPECIFICATION

1. DELIVERY DEVICE / FEEDERS

The simplest feeder Bin hopper with an agitator located inside Possess manually set discharge gate. Best suited for coarse processing.

For grinding operations Roll feeder is suggested. Roll is located below the bin hopper and Possess automatic adjustable discharge gate.

COMPONENTS DESIGN & SPEC

2. ROLL SPECIFICATIONSIN A PAIR

Rolls are 9 to 12 inches in diameterRatio of length to diameter can be as great as 4:1.

ALIGNMENT Sizing dependent gap between the rolls along their length Non Uniform gap Increased maintenance costs & reduced out put,

Overall increased operation costs. Gap Adjusted automatically Through pneumatic or hydraulic cylinders operated by programmable

controller

COUNTER ROTATING SPEEDTypical differentials range from 1.2:1 to 2.0:1 (fast to slow)Typical roll speeds would be 1,300 feet per minute for a 9-inch to

3,140 feet per minute for a 12-inch roll.

ROTATING MOTOR Single motor is used to power a two roll pairWith either belt or chain reduction supplying the differential.

ROLLER MILL OPERATION ADVANTAGES

Energy efficient Uniform particle-size

distribution Little noise Less dust generation No Sig. Heat prod. Decreased fire risk Excellent physical

appearance Easy installation

DISADVANTAGES Little or no effect on

fiber

when required, maintenance can be expensive

may have high initial cost (depends on system design)

For coarse reduction of grain, a roller mill may have a significant advantage over a hammermill in terms of throughput/kwh of energy. For cereal grains processed to typical sizes (600 to 900 microns) for the feed industry, the advantage is about 30 to 50 percent. This translates into reduced operating expense.